Integrated circuit for high side driving of an inductive load

Claim 2

A semiconductor integrated circuit device comprising: a voltage external terminal; a ground external terminal; an input terminal; an output terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current at said internal ground potential node to said ground external terminal; a unidirectional element electrically connected to pass a current flowing from said internal ground potential node of said internal circuit to at least one of said input and output terminals; and a unidirectional element electrically connected to pass a current flowing from said internal ground potential node to the other of said input and output terminals.

Claim 3

A semiconductor integrated circuit device according to claim 1, wherein said unidirectional elements are transistors in the form of diodes.

Claim 4

A semiconductor integrated circuit device according to claim 1, including an isolation region isolating said unidirectional elements from each other and connected at said internal ground potential node.

Claim 5

A semiconductor integrated circuit device according to claim 1, and a unidirectional element electrically connected to transmit current from said voltage external terminal to said internal operating voltage node; and a unidirectional element electrically connected to pass a current flowing from at least one of said input and output terminals to said internal operating voltage node.

Claim 6

A semiconductor integrated circuit device according to claim 4, including a unidirectional element electrically connected to transmit a current flowing from the other of said input and output terminals to said internal operating voltage node.

Claim 7

A semiconductor integrated circuit device according to claim 5, wherein said unidirectional elements are transistors in the form of diodes.

Claim 8

A semiconductor integrated circuit device according to claim 5, including an isolation region isolating said unidirectional elements from each other and connected at said internal ground potential node.

Claim 9

A semiconductor integrated circuit device comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current from said voltage external terminal to said internal operating voltage node; a unidirectional element electrically connected to pass a current flowing from at least one of said input and output terminals to said internal operating voltage node; and means, including said unidirectional elements, for increasing the dynamic voltage range of said at least one of said input and output terminals by permitting the internal circuit operating voltage node to follow the potential at said at least one of said input and output terminals rising above the voltage applied at said voltage external terminal.

Claim 10

A semiconductor integrated circuit device comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current from said voltage external terminal to said internal operating voltage node; a unidirectional element electrically connected to pass a current flowing from at least one of said input and output terminals to said internal operating voltage node; and means, including said unidirectional elements, for increasing the dynamic voltage range of said at least one of said input and output terminals by permitting the internal circuit operating voltage node to follow the potential at said at least one of said input and output terminals rising above the voltage applied at said voltage external terminal.

Claim 11

A semiconductor integrated circuit device comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current from said voltage external terminal to said internal operating voltage node; a unidirectional element electrically connected to pass a current flowing from at least one of said input and output terminals to said internal operating voltage node; and a unidirectional element electrically connected to transmit a current flowing from the other of said input and output terminals to said internal operating voltage node.

Claim 12

A semiconductor integrated circuit device comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current from said voltage external terminal to said internal operating voltage node; a unidirectional element electrically connected to pass a current flowing from at least one of said input and output terminals to said internal operating voltage node; and a unidirectional element electrically connected to transmit a current flowing from the other of said input and output terminals to said internal operating voltage node.

Claim 13

A semiconductor integrated circuit device according to claim 9, wherein said unidirectional elements are transistors in the form of diodes.

Claim 14

A high side inductive load driving circuit, to be connected between a voltage source and an inductive load, comprising: voltage external terminal means for connection to the voltage source; output terminal means for connection to the inductive load; input terminal means for connection to a switching input signal; a ground external terminal means for connection to a ground common with a low side of the inductive load; and active internal circuit means operatively connected to said input terminal means, said output terminal means, said voltage external terminal means and said ground external terminal means for selectively connecting said voltage source at said voltage external terminal means to a high side of said inductive load at said output terminal means in response to the switching input signal at said input terminal means, the active internal circuit means including a power transistor having a transistor output terminal connected to said output terminal means, a transistor terminal connected to said voltage external terminal means, and a transistor control terminal, a control transistor operatively connected to said input terminal means for receiving said switching input signal as a control voltage for selectively directly connecting the control terminal of said power transistor with the output terminal of said power transistor so that said switching input signal can be used to effectively control the power transistor, a semiconductor unidirectional element connected between said control transistor at a circuit ground node and said ground external terminal means to conduct current from said circuit ground node to said ground external terminal means and prevent damage to the circuit elements in the event that the supply voltage is accidentally reversely connected between said voltage external terminal means and said ground external terminal means, and a semiconductor unidirectional element connected between said circuit ground node and the output terminal of said power transistor for conducting current from said circuit ground node to said output terminal of said power transistor for permitting the circuit ground potential to drop below the ground potential at said external ground terminal means when counter electromotive force is generated at said output terminal means, due to said power transistor turning off the power to said inductive load, for correspondingly reducing the voltage below external ground at the control terminal of said power transistor to prevent clamping of voltage at the output terminal means in the internal circuit so that the turning off of the power transistor is guaranteed, thereby increasing the external voltage range of said output terminal means.

Claim 15

A high side inductive load driving circuit, to be connected between a voltage source and an inductive load, comprising: voltage external terminal means for connection to the voltage source; output terminal means for connection to the inductive load; input terminal means for connection to a switching input signal; a ground external terminal means for connection to a ground common with a low side of the inductive load; and active internal circuit means operatively connected to said input terminal means, said output terminal means, said voltage external terminal means and said ground external terminal means for selectively connecting said voltage source at said voltage external terminal means to a high side of said inductive load at said output terminal means in response to the switching input signal at said input terminal means, the active internal circuit means including a power transistor having a transistor output terminal connected to said output terminal means, a transistor terminal connected to said voltage external terminal means, and a transistor control terminal, a control transistor operatively connected to said input terminal means for receiving said switching input signal as a control voltage for selectively directly connecting the control terminal of said power transistor with the output terminal of said power transistor so that said switching input signal can be used to effectively control the power transistor, a semiconductor unidirectional element connected between said control transistor at a circuit ground node and said ground external terminal means to conduct current from said circuit ground node to said ground external terminal means and prevent damage to the circuit elements in the event that the supply voltage is accidentally reversely connected between said voltage external terminal means and said ground external terminal means, and a semiconductor unidirectional element connected between said circuit ground node and the output terminal of said power transistor for conducting current from said circuit ground node to said output terminal of said power transistor for permitting the circuit ground potential to drop below the ground potential at said external ground terminal means when counter electromotive force is generated at said output terminal means, due to said power transistor turning off the power to said inductive load, for correspondingly reducing the voltage below external ground at the control terminal of said power transistor to prevent clamping of voltage at the output terminal means in the internal circuit so that the turning off of the power transistor is guaranteed, thereby increasing the external voltage range of said output terminal means.

Claim 16

The circuit according to claim 11, wherein each of said transistors is a MOSFET.

Claim 17

The circuit according to claim 12, constructed entirely as an integrated circuit on a single substrate, with the drain of said power transistor being the substrate and the voltage external terminal means being directly connected to said substrate.

Claim 18

The circuit according to claim 11, providing a boost voltage means between said transistor terminal of said power transistor and said control terminal of said power transistor, for supplying an added control voltage of a value at least substantially greater than the threshold voltage of said power transistor, so that the voltage at said output terminal means will not be substantially reduced from the voltage source at said voltage external terminal means.

Claim 19

The circuit according to claim 12, including an external ground connected to said ground external terminal means and an inductive load operatively connected between said external ground and said output terminal means; and a positive supply voltage connected to said voltage external terminal means.

Claim 20

The circuit according to claim 15, further including a voltage clamping circuit connected across said inductive load for clamping the counter electromotive voltage from said inductive load when said power transistor is turned off, with the counter electromotive voltage thereby being clamped across the gate to source of said power transistor for proportionally decreasing the turn off time of said power transistor.

Claim 21

The circuit according to claim 16, wherein said clamping circuit includes a diode connected to transmit current from ground to said output terminal means in series with an oppositely connected zener diode, so that the clamping voltage will be the threshold voltage of said diode and the zener voltage of said zener diode, so that the external energy of the inductive load is used to increase the switching speed of the power transistor.

Claim 22

An input circuit, comprising: voltage external terminal means for connection to a voltage source; output terminal means for connection to a load; input terminal means for connection to an input signal; ground external terminal means for connection to a ground external of the circuit; active internal circuit means operatively connected to said input terminal means, said voltage external terminal means, said ground external terminal means and said output terminal means, and including an input transistor having a control terminal directly connected to said input terminal means; a unidirectional device electrically connected between the output terminal of said transistor and said ground external terminal means for conducting current toward said ground external terminal means and establishing a circuit internal ground node at said output terminal of said transistor; a second unidirectional device operatively connected between said internal circuit ground node and said transistor control terminal for conducting current only from said internal circuit ground node to said transistor control terminal; and said unidirectional devices together comprising means to enlarge the input dynamic range of an input signal applied to said input terminal means to below the external ground potential without voltage clamping said input signal at the input terminal means and thereby lowering the internal ground node lower than the external ground applied at said external ground terminal means.

Claim 23

An input circuit, comprising: voltage external terminal means for connection to a voltage source; output terminal means for connection to a load; input terminal means for connection to an input signal; ground external terminal means for connection to a ground external of the circuit; active internal circuit means operatively connected to said input terminal means, said voltage external terminal means, said ground external terminal means and said output terminal means, and including an input transistor having a control terminal directly connected to said input terminal means; a unidirectional device electrically connected between the output terminal of said transistor and said ground external terminal means for conducting current toward said ground external terminal means and establishing a circuit internal ground node at said output terminal of said transistor; a second unidirectional device operatively connected between said internal circuit ground node and said transistor control terminal for conducting current only from said internal circuit ground node to said transistor control terminal; and said unidirectional devices together comprising means to enlarge the input dynamic range of an input signal applied to said input terminal means to below the external ground potential without voltage clamping said input signal at the input terminal means and thereby lowering the internal ground node lower than the external ground applied at said external ground terminal means.

Claim 24

A semiconductor integrated circuit device, comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current at said internal ground potential node to said ground external terminal; a unidirectional element electrically connected to pass a current flowing from said internal ground potential node of said internal circuit to at least one of said input and output terminals; and means, including said unidirectional elements, for increasing the dynamic voltage range of said at least one of said input and output terminals by permitting the internal circuit ground potential node to follow the potential at said at least one of said input and output terminals dropping below ground potential applied at said ground external terminal.

Claim 25

A semiconductor integrated circuit device, comprising: a voltage external terminal; a ground external terminal; an input external terminal; an output external terminal; an active internal circuit operatively connected electrically to all of said terminals and having an internal ground potential node and an internal operating voltage node; a unidirectional element electrically connected to transmit current at said internal ground potential node to said ground external terminal; a unidirectional element electrically connected to pass a current flowing from said internal ground potential node of said internal circuit to at least one of said input and output terminals; and means, including said unidirectional elements, for increasing the dynamic voltage range of said at least one of said input and output terminals by permitting the internal circuit ground potential node to follow the potential at said at least one of said input and output terminals dropping below ground potential applied at said ground external terminal.

Claim 26

The circuit according to claim 11, wherein said unidirectional elements are the emitter to base terminals of respective sense transistors; and further said sense transistors being means for flowing sense current between the collector and emitter of said unidirectional elements so that the sense current determines relative voltage values of said emitter to base terminals.

Claim 27

The circuit according to claim 11, integrated on a single semiconductor chip, and said circuit further including additional active components having a separate second independent internal ground node connected to said external ground terminal means through an additional unidirectional element, so that the second internal circuit ground node potential does not follow a negative swing of voltage at said at least one input and output terminals.

Claim 28

The circuit according to claim 11, completely formed as an integrated circuit on a single substrate; said power transistor being a MOSFET in source follower configuration; said substrate being N-type, forming the drain region of aid power MOSFET and being directly connected to said voltage external terminal means; a P-type region formed within said substrate as the channel region of said power MOSFET, and an N-type source region being formed with said P-type channel region; a P-type isolation region being formed within said substrate and spaced from said power MOSFET; N and P-type regions being formed within said isolation region for constituting said unidirectional elements; a large parasitic diode being formed between said P-type isolation region and said N-type substrate; and said P-type isolation region being connected to said external ground terminal means only through said unidirectional element formed within said P-type isolation region so that reversal of power and ground supply will not produce a high flow of current through said parasitic diode.

Claim 29

The circuit according to claim 22, wherein said circuit ground node is connected directly to said isolation P-type region.

Claim 30

The circuit according to claim 22, including a further isolation region of N-type within said P-type isolation region and having therein active circuit elements formed; and said P-type isolation region and N-type isolation regions being directly connected together at internal circuit ground potential thereby preventing the formation of a parasitic transistor between said N-type substrate, P-type isolation region and N-type isolation region.

Claim 31

A circuit for providing high side driving of an inductive load, comprising: output terminal means for connection to the high voltage side of an inductive load; input circuit means providing a control voltage input signal in active on, inactive off form; supply voltage input terminal means for connection to an external supply voltage; ground terminal means for connection to an external ground; a power MOSFET having its drain connected to said supply voltage input terminal means and its source connected to said output terminal means, and having a gate; first unidirectional means connected between said ground terminal means and an internal ground node, connected to transmit current from the internal ground node to the ground terminal means; second unidirectional means connected between said internal ground node and said power MOSFET source, connected to transmit current from said internal ground node to said power MOSFET source and said output terminal means; first control transistor means connected across said gate and source of said power MOSFET and having a control terminal, and operatively connected to providing sufficient voltage for said power MOSFET gate to turn on when said first control transistor means is turned off and reducing the voltage at the power MOSFET gate sufficiently to turn off said power MOSFET when said first control transistor means is on; second control transistor means operatively connected between said internal ground node and said power MOSFET gate and having a control terminal for turning on and thereby turning off said power MOSFET and thereby sufficiently reducing the voltage at the source of said power MOSFET that said first control transistor means can turn on in response to said input signal; said input circuit means supplying the input signal to the control terminal of each of said first and second control transistor means at a voltage substantially lower than the source voltage of said power MOSFET when said power MOSFET is on; said input circuit means providing a high pulse signal as the active input signal for turning on said first and second control transistor means and selectively providing a low signal as the inactive input signal for turning off said second control transistor means with a stair step ramp; third unidirectional means electrically connected between the gate of said power MOSFET and said second control transistor means for preventing feed of said pulse signal to the gate of said power MOSFET; and said first control transistor means being parallel connected to said second unidirectional means, said second control transistor means and said third unidirectional means.

Claim 32

A circuit for providing high side driving of an inductive load, comprising: output terminal means for connection to the high voltage side of an inductive load; input circuit means providing a control voltage input signal in active on, inactive off form; supply voltage input terminal means for connection to an external supply voltage; ground terminal means for connection to an external ground; a power MOSFET having its drain connected to said supply voltage input terminal means and its source connected to said output terminal means, and having a gate; first unidirectional means connected between said ground terminal means and an internal ground node, connected to transmit current from the internal ground node to the ground terminal means; second unidirectional means connected between said internal ground node and said power MOSFET source, connected to transmit current from said internal ground node to said power MOSFET source and said output terminal means; first control transistor means connected across said gate and source of said power MOSFET and having a control terminal, and operatively connected to providing sufficient voltage for said power MOSFET gate to turn on when said first control transistor means is turned off and reducing the voltage at the power MOSFET gate sufficiently to turn off said power MOSFET when said first control transistor means is on; second control transistor means operatively connected between said internal ground node and said power MOSFET gate and having a control terminal for turning on and thereby turning off said power MOSFET and thereby sufficiently reducing the voltage at the source of said power MOSFET that said first control transistor means can turn on in response to said input signal; said input circuit means supplying the input signal to the control terminal of each of said first and second control transistor means at a voltage substantially lower than the source voltage of said power MOSFET when said power MOSFET is on; said input circuit means providing a high pulse signal as the active input signal for turning on said first and second control transistor means and selectively providing a low signal as the inactive input signal for turning off said second control transistor means with a stair step ramp; third unidirectional means electrically connected between the gate of said power MOSFET and said second control transistor means for preventing feed of said pulse signal to the gate of said power MOSFET; and said first control transistor means being parallel connected to said second unidirectional means, said second control transistor means and said third unidirectional means.

Claim 33

The circuit according to claim 25, completely formed as an integrated circuit on a single substrate except for said input circuit means.

Claim 34

The circuit according to claim 26, further including a zener diode between the output terminal means and the control terminal of said first control transistor means and a zener diode between the output terminal means and the control terminal of said second control transistor means for preventing destruction of said first and second control transistor means by the breakdown voltage of the zener diodes in the event that a turning off of the inductive load would pull the output terminal means voltage far below ground.

Claim 35

The circuit according to claim 27, diode means operatively between the control terminal of said first control transistor means and said input circuit means for preventing high voltage at said output terminal means from feeding current back.

Claim 36

The circuit according to claim 28, further including a resistor connected in parallel across said zener diode of said first control transistor means for providing drain of control terminal voltage when said first control transistor means is turned off.

Claim 37

The circuit according to claim 25, further including a zener diode between the output terminal means and the control terminal of said first control transistor means and a zener diode between the output terminal means and the control terminal of said second control transistor means for preventing destruction of said first and second control transistor means by the breakdown voltage of the zener diodes in the event that a turning off of the inductive load would pull the output terminal means voltage far below ground.

Claim 38

A high side load driving circuit, to be connected between a voltage source and a load, comprising: voltage external terminal means for connection to the voltage source; output terminal means for connection to the load; input terminal means for connection to a switching input signal; a ground external terminal means for connection to a ground common with the low side of the load; active internal circuit means operatively connected to said input terminal means, said output terminal means, said voltage external terminal means and said ground external terminal means for selectively connecting said voltage source at said voltage external terminal means to a high side of said load at said output terminal means in response to the switching input signal at said input terminal means, and having a power switching device having a switch output terminal connected to said output terminal means, a switch terminal connected to said voltage external terminal means, and a switch control terminal; a control device operatively connected to said input terminal means for receiving said switching input signal as a control voltage for selectively directly connecting the switch control terminal of said power switching device with the switch output terminal of said power switching device so that said switching input signal can be used to effectively control the power switching device; a semiconductor unidirectional element connected between a circuit ground node and said ground external terminal means to conduct current from said circuit ground node to said ground external terminal means; a semiconductor unidirectional element connected between said circuit ground node and the switch output terminal of said power switching device for conducting current from said circuit ground node to said switch output terminal of said power switching device; and means, including said semiconductor unidirectional elements, for increasing the dynamic voltage range of said output terminal means by permitting the circuit ground node to follow the potential at said output terminal means dropping below ground potential applied at said ground external terminal means.

Claim 39

A high side load driving circuit, to be connected between a voltage source and a load, comprising: voltage external terminal means for connection to the voltage source; output terminal means for connection to the load; input terminal means for connection to a switching input signal; a ground external terminal means for connection to a ground common with the low side of the load; active internal circuit means operatively connected to said input terminal means, said output terminal means, said voltage external terminal means and said ground external terminal means for selectively connecting said voltage source at said voltage external terminal means to a high side of said load at said output terminal means in response to the switching input signal at said input terminal means, and having a power switching device having a switch output terminal connected to said output terminal means, a switch terminal connected to said voltage external terminal means, and a switch control terminal; a control device operatively connected to said input terminal means for receiving said switching input signal as a control voltage for selectively directly connecting the switch control terminal of said power switching device with the switch output terminal of said power switching device so that said switching input signal can be used to effectively control the power switching device; a semiconductor unidirectional element connected between a circuit ground node and said ground external terminal means to conduct current from said circuit ground node to said ground external terminal means; a semiconductor unidirectional element connected between said circuit ground node and the switch output terminal of said power switching device for conducting current from said circuit ground node to said switch output terminal of said power switching device; and means, including said semiconductor unidirectional elements, for increasing the dynamic voltage range of said output terminal means by permitting the circuit ground node to follow the potential at said output terminal means dropping below ground potential applied at said ground external terminal means.

Claim 40

The circuit according to claim 31, wherein said switching device is a source follower power MOSFET.

Claim 41

The circuit according to claim 32, constructed entirely as an integrated circuit on a single substrate, with the drain of said power MOSFET being the substrate and the voltage external terminal means being directly connected to said substrate.

Claim 42

An integrated driving circuit having a first external terminal for receiving a first supply voltage, a second external terminal for receiving a second supply voltage lower than the first supply voltage, a third external terminal for receiving an externally generated input signal and a fourth external terminal for providing an internally generated output signal, the integrated driving circuit being for use with an inductive load coupled to the fourth external terminal to receive the internally generated output signal and coupled to receive the second supply voltage, the inductive load generating counter electromotive force therein when an operation state of the inductive load is changed from an on-state to an off-state in response to the internally generated output signal, and means coupled to the fourth external terminal for releasing energy of the counter electromotive force in the inductive load when the operation state of the inductive load is changed from the on-state to the off-state, the integrated driving circuit comprising: a power MOSFET having a source-drain path coupled between the first and fourth external terminals and a gate; a control circuit coupled to the third external terminal and the gate of the power MOSFET for driving the power MOSFET in response to the externally generated input signal, the control circuit having a first node coupled to the first external terminal and a second node; first diode means, coupled between the second external terminal and the second node, for transmitting a current from the second node to the second external terminal when the first diode means is turned on; and second diode means, coupled between the second node and the fourth external terminal, for transmitting a current from the second node to the fourth external terminal when the second diode means is turned on.

Claim 43

An integrated driving circuit having a first external terminal for receiving a first supply voltage, a second external terminal for receiving a second supply voltage lower than the first supply voltage, a third external terminal for receiving an externally generated input signal and a fourth external terminal for providing an internally generated output signal, the integrated driving circuit being for use with an inductive load coupled to the fourth external terminal to receive the internally generated output signal and coupled to receive the second supply voltage, the inductive load generating counter electromotive force therein when an operation state of the inductive load is changed from an on-state to an off-state in response to the internally generated output signal, and means coupled to the fourth external terminal for releasing energy of the counter electromotive force in the inductive load when the operation state of the inductive load is changed from the on-state to the off-state, the integrated driving circuit comprising: a power MOSFET having a source-drain path coupled between the first and fourth external terminals and a gate; a control circuit coupled to the third external terminal and the gate of the power MOSFET for driving the power MOSFET in response to the externally generated input signal, the control circuit having a first node coupled to the first external terminal and a second node; first diode means, coupled between the second external terminal and the second node, for transmitting a current from the second node to the second external terminal when the first diode means is turned on; and second diode means, coupled between the second node and the fourth external terminal, for transmitting a current from the second node to the fourth external terminal when the second diode means is turned on.

Claim 44

The integrated driving circuit according to claim 34, wherein the power MOSFET is of an n-channel, wherein the second supply voltages is at a ground potential, and wherein a potential on the fourth external terminal becomes a negative potential lower than the ground potential when the counter electromotive force is generated.

Claim 45

A switching system comprising: an integrated driving circuit including: a first external terminal for receiving a first supply voltage; a second external terminal for receiving a second supply voltage lower than the first supply voltage; a third external terminal for receiving an input signal; a fourth external terminal for providing an output signal; a power MOSFET coupled to have a source-drain path coupled between the first and fourth external terminals and a gate; a control circuit coupled to the third external terminal and the gate of the power MOSFET for driving the power MOSFET in response to the input signal, the control circuit having a first node coupled to the first external terminal and a second node; first diode means, coupled between the second external terminal and the second node, for transmitting a current from the second node to the second external terminal when the first diode means is turned on, and second diode means, coupled between the second node and the fourth external terminal, for transmitting a current from the second node to the fourth external terminal when the second diode means is turned on, an inductive load coupled to the fourth external terminal for receiving the output signal and coupled to receive the second supply voltage, the inductive load generating counter electromotive force therein when an operation state of the inductive load is changed from an on-state to an off-state in response to the output signal; and means coupled to the fourth external terminal for releasing energy of the counter electromotive force in the inductive load when the operation state of the inductive load is changed from the on-state to the off-state.

Claim 46

A switching system comprising: an integrated driving circuit including: a first external terminal for receiving a first supply voltage; a second external terminal for receiving a second supply voltage lower than the first supply voltage; a third external terminal for receiving an input signal; a fourth external terminal for providing an output signal; a power MOSFET coupled to have a source-drain path coupled between the first and fourth external terminals and a gate; a control circuit coupled to the third external terminal and the gate of the power MOSFET for driving the power MOSFET in response to the input signal, the control circuit having a first node coupled to the first external terminal and a second node; first diode means, coupled between the second external terminal and the second node, for transmitting a current from the second node to the second external terminal when the first diode means is turned on, and second diode means, coupled between the second node and the fourth external terminal, for transmitting a current from the second node to the fourth external terminal when the second diode means is turned on, an inductive load coupled to the fourth external terminal for receiving the output signal and coupled to receive the second supply voltage, the inductive load generating counter electromotive force therein when an operation state of the inductive load is changed from an on-state to an off-state in response to the output signal; and means coupled to the fourth external terminal for releasing energy of the counter electromotive force in the inductive load when the operation state of the inductive load is changed from the on-state to the off-state.

Claim 47

The switching system according to claim 36, wherein the power MOSFET is of an n-channel, wherein the second supply voltage is at a ground potential, and wherein a potential on the fourth external terminal becomes a negative potential lower than the ground potential when the counter electromotive force is generated.

Claim 48

The switching system according to claim 36, wherein the inductive load includes one of a motor and a solenoid.

Claim 49

The switching system according to claim 36, wherein the inductive load includes a solenoid employed for an electronic fuel injection in an automobile.

Claim 50

The circuit according to claim 1, further comprising means, including said unidirectional elements, for increasing the dynamic voltage range of said at least one of said input and output terminals by permitting the internal circuit ground potential node to follow the potential at said at least one of said input and output terminals dropping below ground potential applied at said ground external terminal.

Claim 51

A circuit for providing high side driving of an inductive load, comprising: output terminal means for connection to the high voltage side of an inductive load; input circuit means providing a control voltage input signal in active on, inactive off form; supply voltage input terminal means for connection to an external supply voltage; ground terminal means for connection to an external ground; a power MOSFET having its drain connected to said supply voltage input terminal means and its source connected to said output terminal means, and having a gate; first unidirectional means connected between said ground terminal means and an internal ground node, connected to transmit current from the internal ground node to the ground terminal means; first control transistor means connected across said gate and source of said power MOSFET and having a control terminal, and operatively connected for providing sufficient voltage for said power MOSFET gate to turn on when said first control transistor means is turned off and reducing the voltage at the power MOSFET gate sufficiently to turn off said power MOSFET when said first control transistor means is on; second control transistor means operatively connected between said internal ground node and said power MOSFET gate and having a control terminal and for turning on and thereby turning off said power MOSFET and thereby sufficiently reducing the voltage at the source of said power MOSFET that said first control transistor means can turn on in response to said input signal; said input circuit means supplying the input signal to the control terminal of each of said first and second control transistor means at a voltage substantially lower than the source voltage of said power MOSFET when said power MOSFET is on; said input circuit means providing a high pulse signal as the active input signal for turning on said first and second control transistor means and selectively providing a low signal as the inactive input signal for turning off said second control transistor means with a stair step ramp; second unidirectional means electrically connected between the gate of said power MOSFET and said second control transistor means for preventing feed of said pulse signal to the gate of said power MOSFET; and said first control transistor means being parallel connected to said second control transistor means and said second unidirectional means.

Claim 52

A circuit for providing high side driving of an inductive load, comprising: output terminal means for connection to the high voltage side of an inductive load; input circuit means providing a control voltage input signal in active on, inactive off form; supply voltage input terminal means for connection to an external supply voltage; ground terminal means for connection to an external ground; a power MOSFET having its drain connected to said supply voltage input terminal means and its source connected to said output terminal means, and having a gate; first unidirectional means connected between said ground terminal means and an internal ground node, connected to transmit current from the internal ground node to the ground terminal means; first control transistor means connected across said gate and source of said power MOSFET and having a control terminal, and operatively connected for providing sufficient voltage for said power MOSFET gate to turn on when said first control transistor means is turned off and reducing the voltage at the power MOSFET gate sufficiently to turn off said power MOSFET when said first control transistor means is on; second control transistor means operatively connected between said internal ground node and said power MOSFET gate and having a control terminal and for turning on and thereby turning off said power MOSFET and thereby sufficiently reducing the voltage at the source of said power MOSFET that said first control transistor means can turn on in response to said input signal; said input circuit means supplying the input signal to the control terminal of each of said first and second control transistor means at a voltage substantially lower than the source voltage of said power MOSFET when said power MOSFET is on; said input circuit means providing a high pulse signal as the active input signal for turning on said first and second control transistor means and selectively providing a low signal as the inactive input signal for turning off said second control transistor means with a stair step ramp; second unidirectional means electrically connected between the gate of said power MOSFET and said second control transistor means for preventing feed of said pulse signal to the gate of said power MOSFET; and said first control transistor means being parallel connected to said second control transistor means and said second unidirectional means.

Claim 53

The circuit according to claim 41, completely formed as an integrated circuit on a single substrate except for said input circuit means.

Claim 54

The circuit according to claim 42, further including a zener diode between the output terminal means and the control terminal of said first control transistor means and a zener diode between the output terminal means and the control terminal of said second control transistor means for preventing destruction of said first and second control transistor means by the breakdown voltage of the zener diodes in the event that a turning off of the inductive load would pull the output terminal means voltage far below ground.

Claim 55

The circuit according to claim 43, diode means operatively between the control terminal of said first control transistor means and said input circuit means for preventing high voltage at said input circuit means from feeding current back.

Claim 56

The circuit according to claim 44, further including a resistor connected in parallel across said zener diode of said first control transistor means for providing drain of control terminal voltage when said first control transistor means is turned off.

Claim 57

The circuit according to claim 41, further including a zener diode between the output terminal means and the control terminal of said first control transistor means and a zener diode between the output terminal means and the control terminal of said second control transistor means for preventing destruction of said first and second control transistor means by the breakdown voltage of the zener diodes in the event that a turning off of the inductive load would pull the output terminal means voltage far below ground.

Claim 58

A semiconductor integrated circuit device for driving an inductive load, the semiconductor integrated circuit device, comprising the following elements: a semiconductor substrate; a first terminal for receiving a first supply voltage; a second terminal for receiving a second supply voltage lower than the first supply voltage; an input terminal for receiving an input signal; an output terminal to which the inductive load is to be coupled; an output transistor having an on state and an off state and a control terminal, the output transistor having a current path coupled between the first terminal and the output terminal so that the inductive load generates counter electromotive force therein when an operation state of the output transistor changes from the on state to the off state; a control circuit coupled to the input terminal and responsive to the input signal on the input terminal for providing a driving signal to the control terminal of the output transistor, and the control circuit further having a first node coupled to the first terminal and a second node; first means for coupling the second node to the second terminal when the first and second terminals receive the first and second supply voltages, respectively, and uncoupling the second node to the second terminal when the first and second terminals receive the second the first supply voltages, respectively; second means coupled to the output terminal for feeding a voltage on the output terminal to the control terminal of the output transistor when the inductive load is generating the counter electromotive force therein, and for thereby maintaining a voltage across the output terminal and the control terminal of the output transistor sufficient for maintaining the off state of the output transistor during the generation of the counter electromotive force by the load; said first and second means increasing the dynamic voltage range of said output terminal by permitting the control terminal to follow the potential at the output terminal dropping below the second supply voltage at the second terminal; and all of the elements being formed on the semiconductor substrate.

Claim 59

A semiconductor integrated circuit device for driving an inductive load, the semiconductor integrated circuit device, comprising the following elements: a semiconductor substrate; a first terminal for receiving a first supply voltage; a second terminal for receiving a second supply voltage lower than the first supply voltage; an input terminal for receiving an input signal; an output terminal to which the inductive load is to be coupled; an output transistor having an on state and an off state and a control terminal, the output transistor having a current path coupled between the first terminal and the output terminal so that the inductive load generates counter electromotive force therein when an operation state of the output transistor changes from the on state to the off state; a control circuit coupled to the input terminal and responsive to the input signal on the input terminal for providing a driving signal to the control terminal of the output transistor, and the control circuit further having a first node coupled to the first terminal and a second node; first means for coupling the second node to the second terminal when the first and second terminals receive the first and second supply voltages, respectively, and uncoupling the second node to the second terminal when the first and second terminals receive the second the first supply voltages, respectively; second means coupled to the output terminal for feeding a voltage on the output terminal to the control terminal of the output transistor when the inductive load is generating the counter electromotive force therein, and for thereby maintaining a voltage across the output terminal and the control terminal of the output transistor sufficient for maintaining the off state of the output transistor during the generation of the counter electromotive force by the load; said first and second means increasing the dynamic voltage range of said output terminal by permitting the control terminal to follow the potential at the output terminal dropping below the second supply voltage at the second terminal; and all of the elements being formed on the semiconductor substrate.

Claim 60

The semiconductor integrated circuit device according to claim 47, wherein the output transistor is an N channel power MOSFET, wherein the current path of the output transistor is a source-drain path of the power MOSFET, and wherein the control terminal of the output transistor is a gate of the power MOSFET.

Claim 61

The semiconductor integrated circuit device according to claim 48, wherein the first means is a diode.

Claim 62

The semiconductor integrated circuit device according to claim 49, wherein the semiconductor substrate includes an isolation region in which the diode is formed, and wherein the second node is constructed of the isolation region.

Claim 63

The semiconductor integrated circuit device according to claim 48, wherein the second means is a diode.

Claim 64

The semiconductor integrated circuit device according to claim 48, wherein the first means is a first diode, and wherein the second means is a second diode.

Claim 65

The semiconductor integrated circuit device, according to claim 52, wherein the semiconductor substrate includes an isolation region in which the first and second diodes are formed in isolation from each other, and wherein the second node is constructed of the isolation region.

Claim 66

A semiconductor integrated circuit device, comprising: a semiconductor substrate; a first terminal for receiving a first supply voltage; a second terminal for receiving a second supply voltage lower than the first supply voltage; an input terminal for receiving an input signal; an output terminal to which an inductive load is to be coupled; an internal active circuit coupled to the input terminal and responsive to the input signal on the input terminal for providing an output signal to the output terminal, the internal active circuit further having an output transistor with a control terminal, a first node coupled to the first terminal and a second node; means for coupling the second node to the second terminal when the first and second terminals receive the first and second supply voltages, respectively, uncoupling the second node to the second terminal when the first and second terminals receive the second and first supply voltages, respectively, and increasing the dynamic voltage range of said control terminal by permitting the control terminal to follow the potential at the output terminal dropping below the second supply voltage at said second terminal; and the semiconductor substrate including an isolation region in which the means for coupling is formed; and wherein the second node is constructed of the isolation region; and all of the elements being on the one semiconductor substrate.

Claim 67

A semiconductor integrated circuit device, comprising: a semiconductor substrate; a first terminal for receiving a first supply voltage; a second terminal for receiving a second supply voltage lower than the first supply voltage; an input terminal for receiving an input signal; an output terminal to which an inductive load is to be coupled; an internal active circuit coupled to the input terminal and responsive to the input signal on the input terminal for providing an output signal to the output terminal, the internal active circuit further having an output transistor with a control terminal, a first node coupled to the first terminal and a second node; means for coupling the second node to the second terminal when the first and second terminals receive the first and second supply voltages, respectively, uncoupling the second node to the second terminal when the first and second terminals receive the second and first supply voltages, respectively, and increasing the dynamic voltage range of said control terminal by permitting the control terminal to follow the potential at the output terminal dropping below the second supply voltage at said second terminal; and the semiconductor substrate including an isolation region in which the means for coupling is formed; and wherein the second node is constructed of the isolation region; and all of the elements being on the one semiconductor substrate.

Claim 68

The semiconductor integrated circuit device according to claim 54, further including: second means coupled to the output terminal for feeding a voltage on the output terminal to the control terminal of the output transistor when the inductive load is generating a counter electromotive force therein, so that the off state of the output transistor continues for the generation of the counter electromotive force.