Electronic system, semiconductor integrated circuit and termination device

Claim 2

The electronic system as claimed in claim 1, wherein the first and second parts of said termination voltage circuit are connected in series.

Claim 3

The electronic system as claimed in claim 1, wherein: the second part comprises an operational amplifier having a first input terminal receiving a divided voltage derived from the first voltage, a second input terminal, and an output terminal connected to the second input terminal; and the second voltage is output via said output terminal and is equal to the first voltage.

Claim 4

The electronic system as claimed in claim 1, further comprising second resistors connected to branch points, the plurality of electronic circuits being coupled to the branch points of the bus via said second resistors.

Claim 5

The electronic system as claimed in claim 4, wherein the second resistors have resistance values which produce driving currents for driving the output circuits, said driving currents being equal to those obtained if the second resistors are omitted and the power supply voltage supplied to the output circuits is increased.

Claim 6

The electronic system as claimed in claim 1, further comprising a second resistor which connects at least one electronic circuit to the bus, the remaining electronic circuits being directly connected to the bus.

Claim 7

The electronic system as claimed in claim 6, wherein: driving currents for driving the output circuits of the remaining electronic circuits directly connected to the bus have a first driving current value viewed from the bus; driving circuits for driving the output circuit of said at least one electronic circuit connected to the bus via the second resistor has a second driving current value; and the first driving current value is equal to or nearly equal to the second driving current value.

Claim 8

The electronic system as claimed in claim 1, wherein a value of a characteristic impedance of a wire connecting a second resistor and one of the plurality of electronic circuits connected to the bus via the second resistor is equal to or less than a resistance value of the second resistor and half of a value of a characteristic impedance of the bus.

Claim 9

The electronic system as claimed in claim 1, wherein at least one of the plurality of electronic circuits directly connected to the bus provides an output signal via a second resistor disposed closed to the output circuit of said at least one of the plurality of electronic circuits.

Claim 10

The electronic system as claimed in claim 9, wherein said second resistor has a negative temperature coefficient.

Claim 11

The electronic system as claimed in claim 9, wherein said second resistor is arranged in a package of said at least one of the plurality of electronic circuits.

Claim 12

The electronic system as claimed in claim 1, wherein the first voltage generated by said first part depends on operation temperatures of the output circuits of some or all of the plurality of electronic circuits, and has a positive temperature coefficient.

Claim 13

The electronic system as claimed in claim 12, wherein the second voltage generated by said second part depends on operation temperatures of the output circuits of some or all of the plurality of electronic circuits, and has a positive temperature coefficient.

Claim 14

The electronic system as claimed in claim 1, further comprising a temperature sensor provided at least one of the plurality of electronic circuits, wherein the first part generates the first voltage so as to be varied in response to a temperature sensed by the temperature sensor, and has a positive temperature coefficient.

Claim 15

The electronic system as claimed in claim 14, wherein the second part generates the second voltage so as to be varied in response to the temperature sensed by the temperature sensor, and has another positive temperature coefficient.

Claim 16

The electronic system as claimed in claim 1, wherein: at least one of the plurality of electronic circuits is connected to the bus via a second resistor; the first voltage generated by the first part depends on temperatures of some or all of electronic circuits directly connected to the bus, and has a positive temperature coefficient.

Claim 17

The electronic system as claimed in claim 16, wherein the second voltage generated by the first part depends on the temperatures of some or all of electronic circuits directly connected to the bus, and has another positive temperature coefficient.

Claim 18

The electronic system as claimed in claim 1, further comprising a temperature sensor provided at least one of the plurality of electronic circuits directly connected to the bus, wherein the first part generates the first voltage so as to be varied in response to a temperature sensed by the temperature sensor, and has a positive temperature coefficient.

Claim 19

The electronic system as claimed in claim 18, wherein the second part generates the second voltage so as to be varied in response to the temperature sensed by the temperature sensor, and has another positive temperature coefficient.

Claim 20

The electronic system as claimed in claim 1, wherein each of the output circuits of the plurality of electronic circuits comprises a pull-up element of a first transistor formed of a p-channel insulation gate type field effect transistor, and a pull-down element of a second transistor formed of an n-channel insulation gate type field effect transistor.

Claim 21

The electronic system as claimed in claim 20, further comprising a first inverter of a complementary type driving the first transistor, and a second inverter of the complementary type driving the second transistor, wherein the first and second inverters are supplied with a power supply voltage equal to the sum of the first voltage and the second voltage.

Claim 22

The electronic system as claimed in claim 1, wherein: each of the output circuits of the plurality of electronic circuits comprises a pull-up element of a first transistor formed of an n-channel insulation gate type field effect transistor, and a pull-down element of a second transistor formed of a p-channel insulation gate type field effect transistor; and a threshold voltage of the first transistor is equal to or higher of a low-level output signal output from each of the output circuits, and is lower than a threshold voltage of the second transistor.

Claim 23

The electronic system as claimed in claim 1, wherein: each of the output circuits of the plurality of electronic circuits comprises a pull-up element of a first transistor formed of an n-channel insulation gate type field effect transistor of a depletion type, and a pull-down element of a second transistor formed of a p-channel insulation gate type field effect transistor of an enhancement type; and a threshold voltage of the first transistor is equal to or higher than a low-signal level output from each of the output circuits.

Claim 24

The electronic system as claimed in claim 1, further comprising a packaged termination device having the first termination resistors.

Claim 25

The electronic system as claimed in claim 1, further comprising a packaged termination device having the first termination resistors, at least one of the plurality of electronic circuits and said packaged termination device being arranged on a circuit board in a stack formation.

Claim 26

The electronic system as claimed in claim 24, wherein the packaged termination device has a reference voltage output terminal via which the termination voltage is output as a reference voltage used in the plurality of electronic circuits.

Claim 27

The electronic system as claimed in claim 3, further comprising a packaged termination device having the first termination resistors and said second part of the termination voltage circuit.

Claim 28

The electronic system as claimed in claim 3, further comprising a packaged termination device having the first termination resistors and the second part of the termination voltage circuit, wherein at least one of the plurality of electronic circuits and the packaged termination device are arranged on a circuit board in a stack formation.

Claim 29

The electronic system as claimed in claim 27, wherein the packaged termination device has a reference voltage output terminal via which the second voltage is output as a reference voltage used in the plurality of electronic circuits.

Claim 30

The electronic system as claimed in claim 3, wherein said operational amplifier comprises: a first differential amplifier circuit supplied, as a power supply voltage, with said first voltage and comprised of driving transistors formed of first and second n-channel insulation gate type field effect transistors; a second differential amplifier circuit supplied, as a power supply voltage, with said first voltage and comprised of driving transistors formed of first and second p-channel insulation gate type field effect transistors; and an output circuit supplied, as a power supply voltage, with said first voltage and comprised of a pull-up element driven by said first differential amplifier circuit and formed of a third p-channel insulation gate type field effect transistor and a pull-down element driven by said second differential amplifier circuit and formed of a third n-channel insulation gate type field effect transistor, wherein: a connection node at which a gate of the first p-channel insulation gate type field effect transistor and a gate of the first n-channel insulation gate type field effect transistor are connected together is connected to said first input terminal; a connection node at which a gate of the second p-channel insulation gate type field effect transistor and a gate of the second n-channel insulation gate type field effect transistor are connected together is connected to said second input terminal; and an output terminal of said output circuit of the operational amplifier forms the output terminal of the operational amplifier.

Claim 31

The electronic system as claimed in claim 1, wherein one of the first termination resistors has a resistance value greater than an effective characteristic impedance of the bus and smaller than a characteristic impedance of the bus obtained when no load is connected to the bus.

Claim 32

An electronic circuit comprising: an output circuit having a first pull-up element formed of a first p-channel insulation gate type field effect transistor, and a first pull-down element formed of a first n-channel insulation gate type field effect transistor; a first inverter having a second pull-up element formed of a second p-channel insulation gate type field effect transistor, and a second pull-down element formed of a second n-channel insulation gate type field effect transistor; and a second inverter having a third pull-up element formed of a third p-channel insulation gate type field effect transistor, and a third pull-down element formed of a third n-channel insulation gate type field effect transistor, a power supply voltage supplied to said first and second inverters being the same as power supply voltage supplied to said output circuit.

Claim 33

The electronic circuit as claimed in claim 32, wherein the power supply voltage supplied to said output circuit is supplied, as a back bias voltage, to the second and third p-channel insulation gate type field effect transistors.

Claim 34

An electronic circuit comprising: an output circuit having a first pull-up element formed of a first n-channel insulation gate type field effect transistor, and a first pull-down element formed of a second n-channel insulation gate type field effect transistor, the first n-channel insulation gate type field effect transistor has a threshold voltage equal to or higher than a low-level signal output from said output circuit and is lower than a threshold voltage of said second n-channel insulation gate type field effect transistor.

Claim 35

An electronic circuit comprising: an output circuit having a first pull-up element formed of a first n-channel insulation gate type field effect transistor of a depletion type, and a first pull-down element formed of a second n-channel insulation gate type field effect transistor of an enhancement type, the first n-channel insulation gate type field effect transistor has a threshold voltage equal to or higher than a low-level signal output from said output circuit.

Claim 36

A termination device applied to an electronic system comprising: a plurality of electronic circuits each having a signal input and output function; and a bus to which the plurality of electronic circuits are connected, said termination device comprising: termination resistors connected to ends of the bus; and a member packaging said termination resistors.

Claim 37

The termination device as claimed in claim 36, further comprising a termination voltage circuit packaged by said member and composed of a first part generating a first voltage and a second part generating a second voltage, a sum of the first voltage and the second voltage being supplied, as a power supply voltage, to output circuits of the plurality of electronic circuits connected to the bus, the second voltage being supplied to the first termination resistors as a termination voltage.

Claim 38

The termination device as claimed in claim 37, further comprising a reference voltage output terminal via which said second voltage is output as a reference voltage used for the plurality of electronic circuits.

Claim 39

The termination device as claimed in claim 37, wherein the termination resistors and at least one of the plurality of electronic circuits are arranged in a stack formation.

Claim 40

An electronic system comprising: a plurality of electronic circuits having a signal input and output function and a push-pull type output circuit; a bus to which the plurality of electronic circuits are connected; and a termination device having a first nonlinear element having a rise characteristic, and a second non-linear element having a rise characteristic, the first non-linear element being connected between a termination voltage line and said bus in a forward direction, the second non-linear element being connected, in the forward direction, between the bus and a voltage line carrying a voltage lower than a termination voltage supplied via the termination voltage line, no current flowing in the bus when no signal is transmitted via the bus.

Claim 41

The electronic system as claimed in claim 40, wherein said first and second non-linear elements are diodes.

Claim 42

The electronic system as claimed in claim 40, wherein said first and second non-linear elements are series circuits, each having a diode and a resistor connected in series.

Claim 43

The electronic system as claimed in claim 40, wherein said first and second non-linear elements are insulation gate type field effect transistors which are diode-connected.

Claim 44

The electronic system as claimed in claim 40, wherein: said first non-linear element comprises an n-channel insulation gate type field effect transistor having a drain receiving the termination voltage, a source connected to the bus, and a gate supplied with a first bias voltage; and said second non-linear element comprises a p-channel insulation gate type field effect transistor having a source connected to the bus, a drain connected to said voltage line via which the voltage lower than the termination voltage is supplied, and a gate supplied with a second bias voltage.

Claim 45

The electronic system as claimed in claim 44, wherein a value obtained by subtracting the second bias voltage from the first bias voltage is less than a sum of a threshold voltage of the n-channel insulation gate type field effect transistor and an absolute value of a threshold voltage of the p-channel insulation gate type field effect transistor.

Claim 46

The electronic system as claimed in claim 44, further comprising: a first bias voltage generating circuit including a first operational amplifier and generating said first bias voltage; and a second bias voltage generating circuit including a second operational amplifier and generating said second bias voltage.

Claim 47

The electronic system as claimed in claim 46, wherein said first operational amplifier comprises: a first differential amplifier circuit having driving transistors formed of first and second n-channel insulation gate type field effect transistors; a second differential amplifier having driving transistors formed of first and second p-channel insulation gate type field effect transistors; and a first output circuit having a pull-up element driven by the first differential amplifier circuit and formed of a third p-channel insulation gate type field effect transistor, and a pull-down element driven by the second differential amplifier circuit and formed of a third n-channel insulation gate type field effect transistor, the first operational amplifier having a first input terminal corresponding to a first connection node at which a gate of the first p-channel insulation gate type field effect transistor and a gate of the first n-channel insulation gate type field effect transistor are connected together, a second input terminal corresponding to a second connection node at which a gate of the second p-channel insulation gate type field effect transistor and a gate of the second n-channel insulation gate type field effect transistor are connected together, and an output terminal corresponding to an output terminal of said first output circuit, the output terminal of the first operational amplifier being connected to the first input terminal thereof, the second input terminal being supplied with a reference voltage, said first bias voltage being obtained at the output terminal of the first operational amplifier, and wherein said second bias voltage generating circuit comprises: a third differential amplifier circuit having driving transistors formed of fourth and fifth n-channel insulation gate type field effect transistors; a fourth differential amplifier having driving transistors formed of fourth and fifth p-channel insulation gate type field effect transistors; and a second output circuit having a pull-up element driven by the third differential amplifier circuit and formed of a sixth third p-channel insulation gate type field effect transistor, and a pull-down element driven by the fourth differential amplifier circuit and formed of a sixth n-channel insulation gate type field effect transistor, the second operational amplifier having a first input terminal corresponding to a third connection node at which a gate of the fourth p-channel insulation gate type field effect transistor and a gate of the fourth n-channel insulation gate type field effect transistor are connected together, a second input terminal corresponding to a fourth connection node at which a gate of the fifth p-channel insulation gate type field effect transistor and a gate of the fifth n-channel insulation gate type field effect transistor are connected together, and an output terminal corresponding to an output terminal of said second output circuit, the output terminal of the second operational amplifier being connected to the first input terminal thereof, the second input terminal being supplied with the reference voltage, said second bias voltage being obtained at the output terminal of the first operational amplifier.

Claim 48

The electronic system as claimed in claim 40, wherein said termination device includes an integrated circuit having the first and second non-linear elements, and a termination voltage generating circuit connected to the termination voltage line.

Claim 49

The electronic system as claimed in claim 40, wherein said termination device has an integrated circuit having the first and second non-linear elements, and a reference voltage output terminal via which the reference voltage is output.

Claim 50

The electronic system as claimed in claim 40, wherein the termination device and the plurality of electronic circuits are arranged on a circuit board in a stack formation.

Claim 51

The electronic system as claimed in claim 40, further comprising: a third non-linear element having a rise characteristic; and a fourth non-linear element having a rise characteristic, the third non-linear element being connected between the termination voltage line and said bus in the forward direction, the fourth non-linear element being connected, in the forward direction, between the bus and the voltage line carrying the voltage lower than the termination voltage supplied via the termination voltage line, a reference voltage necessary for operations of input circuits of the plurality of electronic circuits is output via a connection node at which the third and fourth non-linear elements are connected in series.

Claim 52

The electronic system as claimed in claim 51, wherein said third and fourth non-linear elements comprise diodes.

Claim 53

The electronic system as claimed in claim 51, wherein said third and fourth non-linear elements comprise series circuits, each having a diode and a resistor connected in series.

Claim 54

The electronic system as claimed in claim 51, wherein said third and fourth non-linear elements comprise insulation gate type field effect transistors which are diode-connected.

Claim 55

A termination device comprising: a first non-linear element having a rise characteristic; and a second non-linear element having a rise characteristic, the first non-linear element being connected, in a forward direction, between a bus and a termination voltage line via which a termination voltage is supplied, the second non-linear element being connected, in the forward direction, between the bus and a voltage line via which a voltage lower than the termination voltage is supplied.

Claim 56

The termination device as claimed in claim 55, further comprising a termination voltage generating circuit connected to the termination voltage line, the termination voltage generating circuit generating the termination voltage.

Claim 57

The termination device as claimed in claim 55, wherein said first and second non-linear elements comprise diodes.

Claim 58

The termination device as claimed in claim 55, wherein said first and second non-linear elements comprise series circuits, each having a diode and a resistor connected in series.

Claim 59

The termination device as claimed in claim 55, wherein said first and second non-linear elements comprise insulation gate type field effect transistors which are diode-connected.

Claim 60

An electronic circuit comprising: a plurality of logic decision circuits, each having a first load element having a first end connected to a power supply line supplying a power supply voltage, and a first n-channel field effect transistor of an insulation gate type having a drain connected to a second end of the first load element, a gate supplied with an inner reference voltage via a first input protection circuit, and a source receiving a transmitted signal, an output signal obtained by making a logic decision on the transmitted signal being output via the drain; and an inner reference voltage generating circuit having a second load element having a first end connected to said power supply line, a second n-channel field effect transistor of the insulation gate type having a drain connected to a second end of the second load element, a gate connected to the drain of the second n-channel field effect transistor and the gate of the first n-channel field effect transistor, and a source receiving a reference voltage via a reference voltage input terminal and a second input protection circuit, the reference voltage being used to make said logic decision, and a capacitor having a first end connected to the gate of the second n-channel field effect transistor and a second end connected to the second input protection circuit, said inner reference voltage being obtained at the gate of the second n-channel field effect transistor, the plurality of logic decision circuits and said inner reference voltage generating circuit forming input circuits of electronic circuits connected to the bus through which the transmitted signal passes.

Claim 61

The electronic circuit as claimed in claim 60, wherein the first and second load elements comprise p-channel insulation gate type field effect transistors having sources corresponding to the respective first terminals, drains corresponding to the respective second terminals, and gates receiving a bias voltage.

Claim 62

An electronic circuit comprising: a plurality of logic decision circuits, each having a first load element having a first end connected to a power supply line supplying a power supply voltage, and a first n-channel field effect transistor of an insulation gate type having a drain connected to a second end of the first load element, a gate supplied with an inner reference voltage via a first input protection circuit, and a source receiving a transmitted signal, an output signal obtained by making a logic decision on the transmitted signal being output via the drain; and an inner reference voltage generating circuit having a second load element having a first end connected to said power supply line, a second n-channel field effect transistor of the insulation gate type having a drain connected to a second end of the second load element, a gate connected to the drain of the second n-channel field effect transistor and the gate of the first n-channel field effect transistor, and a source receiving a reference voltage via a reference voltage input terminal and a second input protection circuit, the reference voltage being used to make said logic decision, and an operational amplifier having a non-inverting input terminal connected to the source of the second n-channel field effect transistor, an inverting input terminal connected to an output terminal thereof and the gate of the first n-channel field effect transistor, said inner reference voltage being obtained at the output terminal of the operational amplifier, the plurality of logic decision circuits and said inner reference voltage generating circuit forming input circuits of electronic circuits connected to the bus through which the transmitted signal passes.

Claim 63

The electronic circuit as claimed in claim 62, wherein the first and second load elements comprise p-channel insulation gate type field effect transistors having sources corresponding to the respective first terminals, drains corresponding to the respective second terminals, and gates receiving a bias voltage.

Claim 64

An electronic circuit comprising: a plurality of logic decision circuits, each having a first load element having a first end connected to a power supply line supplying a power supply voltage, and a first n-channel field effect transistor of an insulation gate type having a drain connected to a second end of the first load element, a gate supplied with an inner reference voltage, and a source, and a first variable impedance element having a current input terminal connected to the source, a current output terminal set to a group potential, and a control terminal receiving a transmitted signal via which a transmitted signal input terminal and a first input protection circuit, an output signal obtained by making a logic decision on the transmitted signal being output via the drain of the first n-channel field effect transistor; and an inner reference voltage generating circuit having a second load element having a first end connected to the power supply line, a second n-channel field effect transistor of the insulation gate type having a drain connected to a second terminal of the second load element, a gate connected to the second terminal and the gate of the first n-channel field effect transistor, and a source, and a second variable impedance element having a current input terminal connected to the source of the second n-channel field effect transistor, and a current output terminal set to the ground potential, and a control terminal receiving a reference voltage via a reference voltage input terminal and a second input protection circuit, the reference voltage being used to make the logic decision on the transmitted signal, the inner reference voltage being obtained at the gate of the second n-channel field effect transistor.

Claim 65

The electronic circuit as claimed in claim 64, wherein the first and second variable impedance elements respectively comprise p-channel insulation gate type field effect transistors having sources corresponding to the respective current input terminals, drains corresponding to the respective current output terminals, and gates corresponding to the respective control terminals.

Claim 66

The electronic circuit as claimed in claim 64, wherein the first and second variable impedance elements respectively comprise n-channel insulation gate type filed effect transistors having drains corresponding to the respective current input terminals, sources corresponding to the respective current output terminals, and gates corresponding to the respective current control terminals.

Claim 67

The electronic circuit as claimed in claim 66, wherein the n-channel insulation gate type field effect transistors are of a depletion type.

Claim 68

The electronic circuit as claimed in claim 64, wherein the first and second load elements comprise p-channel insulation gate type field effect transistors having sources corresponding to the respective first terminals, drains corresponding to the respective second terminals, and gates receiving a bias voltage.

Claim 69

An electronic circuit comprising: a differential amplifier circuit supplied with an input signal on which a logic decision should be made, and a reference voltage used to make the logic decision; and an input circuit including a current control circuit which controls said differential amplifier circuit so that a variation in a current flowing in the differential amplifier circuit with respect to a change of the reference voltage within a predetermined range.

Claim 70

The electronic circuit as claimed in claim 69, wherein said differential amplifier circuit comprises: first and second loads respectively having first ends connected to a first power supply line via which a first power supply voltage is supplied; a first transistor formed of an insulation gate type field effect transistor having a drain connected to a second end of the first load, a gate supplied with the input signal, and a source; a second transistor formed of an insulation gate type field effect transistor having a drain connected to a second end of the second load, a gate supplied with the reference voltage, and a source connected to the source of the first transistor; and a variable resistance circuit having a first end connected to the sources of the first and second transistors, and a second end connected to a second power supply line via which a second power supply voltage is supplied, an output signal of said electronic circuit being output via at least one of the drains of the first and second transistors.

Claim 71

The electronic circuit as claimed in claim 70, wherein: the first and second transistors are of an n-channel type; and the current control circuit increases a resistance value of the variable resistance circuit when the reference voltage is relatively high and decreases the resistance value of the variable resistance circuit when the reference voltage is relatively low.

Claim 72

The electronic circuit as claimed in claim 71, wherein: the first load comprises a third transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a drain connected to the drain of the first transistor, and a source; and the second load comprises a fourth transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate, and a drain connected to the gate of the fourth transistor and the gate of the third transistor.

Claim 73

The electronic circuit as claimed in claim 71, wherein said variable resistance circuit comprises a third transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the second power supply line, and a gate controlled by said current control circuit.

Claim 74

The electronic circuit as claimed in claim 71, wherein said variable resistance circuit comprises: a third transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the second power supply line, and a gate controlled by said current control circuit; and a fourth transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the second power supply line, and a gate supplied with said reference voltage.

Claim 75

The electronic circuit as claimed in claim 73, wherein said current control circuit comprises: a fourth transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; and a resistance element having a first end connected to the drain of the fourth transistor, and a second end connected to the second power supply line, the first end of said resistance element connected to the drain of the fourth transistor being connected to the gate thereof.

Claim 76

The electronic circuit as claimed in claim 74, wherein said current control circuit comprises: a fifth transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; and a resistance element having a first end connected to the drain of the fifth transistor, and a second end connected to the second power supply line, the first end of said resistance element connected to the drain of the fifth transistor being connected to the gate thereof.

Claim 77

The electronic circuit as claimed in claim 73, wherein the current control circuit comprises: a fourth transistor of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; and a fifth transistor of an n-channel insulation gate type field effect transistor having a gate, a drain connected to the gate of the fifth transistor and the drain of the fourth transistor, and a source connected to the second power supply line, the drains of the fourth and fifth transistors being connected to the gate of the third transistor.

Claim 78

The electronic circuit as claimed in claim 74, wherein the current control circuit comprises: a fifth transistor of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; and a sixth transistor of an n-channel insulation gate type field effect transistor having a gate, a drain connected to the gate of the sixth transistor and the drain of the fifth transistor, and a source connected to the second power supply line, the drains of the fifth and sixth transistors being connected to the gate of the third transistor.

Claim 79

The electronic circuit as claimed in claim 73, wherein said current control circuit comprises: a fourth transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; a fifth transistor having a drain connected to the drain of the fourth transistor, a gate supplied with said reference voltage, and a source; and a sixth transistor having a drain connected to the drain of the fifth transistor, a gate connected to the gate of the fourth transistor, and a source connected to the second power supply line, the drains of the fourth and fifth transistors being connected to the gate of the third transistor.

Claim 80

The electronic circuit as claimed in claim 74, wherein said current control circuit comprises: a fifth transistor having a source connected to the first power supply line, a gate supplied with said reference voltage, and a drain; a sixth transistor having a drain connected to the drain of the fifth transistor, a gate supplied with said reference voltage, and a source; and a seventh transistor having a drain connected to the drain of the sixth transistor, a gate connected to the gate of the fifth transistor, and a source connected to the second power supply line, the drains of the fifth and sixth transistors being connected to the gate of the third transistor.

Claim 81

The electronic circuit as claimed in claim 73, wherein said current control circuit comprises: a monitor circuit which monitors the current flowing in the variable resistance circuit; and a feedback control circuit which controls a gate voltage of the third transistor so that the current monitored by the monitor circuit is maintained at an approximately constant level.

Claim 82

The electronic circuit as claimed in claim 81, wherein said monitor circuit comprises: a resistor having a first end connected to the first power supply line, and a second end; fourth and fifth transistors respectively formed of n-channel insulation gate type field effect transistors respectively having gates having gate widths equal to 1/m of that of each of the first and second transistors where m ≧ 1, drains connected to the second end of said resistor, and sources connected to each other, the reference voltage being supplied to the gates of the fourth and fifth transistors; and a sixth transistor formed of an n-channel insulation gate type field effect transistor having a gate having a gate width equal to said 1/m, a drain connected to the sources of said fourth and fifth transistors, and a source connected to the second power supply line, said feedback control circuit comprising a differential amplifier circuit including: a first input terminal connected to the drains of the fourth and fifth transistors; a second input terminal supplied with a predetermined voltage; and an output terminal via which an output voltage in phase with a voltage applied to said first input terminal is provided, the output terminal of said feedback control circuit being connected to the gate of said third transistor.

Claim 83

The electronic circuit as claimed in claim 72, wherein said variable resistance circuit comprises a fifth transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the second power supply line, and a gate controlled by said current control circuit, wherein said monitor circuit comprises: a sixth transistor formed of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the third transistor where m ≧ 1, a source connected to the first power supply line, and a drain; a seventh transistor formed of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the fourth transistor, a source connected to the first power supply line, and a drain connected to the gate of the seventh transistor and the gate of the sixth transistor; an eighth transistor formed of an n-channel insulation gate type field effect transistor having a gate width equal to 1/m of that of the first transistor, a drain connected to the drain of the sixth transistor, and a source; and a ninth transistor formed of an n-channel insulation gate type field effect transistor having a gate width equal to 1/m of that of the second transistor, a drain connected to the drain of the seventh transistor, and a source connected to the eighth transistor, the gate of the ninth transistor receiving said reference voltage; and a tenth transistor formed of an n-channel insulation gate type field effect transistor having a gate width equal to 1/m of that of the fifth transistor, a drain connected to the sources of the eighth and ninth transistors, and a source connected to the second power supply line, said feedback circuit comprising a differential amplifier circuit comprising: a first input terminal connected to the drains of the sixth and eighth transistors; a second input terminal receiving a constant voltage; and an output terminal outputting a voltage in phase with a voltage applied to the first input terminal, said output terminal of the differential amplifier circuit being connected to the gates of the fifth and tenth transistors.

Claim 84

The electronic circuit as claimed in claim 69, wherein: the first and second transistors are of a p-channel type; and the current control circuit decreases a resistance value of the variable resistance circuit when the reference voltage is relatively high, and increases the resistance value of the variable resistance circuit when the reference voltage is relatively low.

Claim 85

The electronic circuit as claimed in claim 84, wherein: the first load comprises a third transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the second power supply line, a drain connected to the drain of the first transistor, and a source; and the second load comprises a fourth transistor formed of a p-channel insulation gate type field effect transistor having a source connected to the second power supply line, a gate, and a drain connected to the gate of the fourth transistor and the gate of the third transistor.

Claim 86

The electronic circuit as claimed in claim 71, wherein said variable resistance circuit comprises a third transistor formed of a p-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the first power supply line, and a gate controlled by said current control circuit.

Claim 87

The electronic circuit as claimed in claim 85, wherein said variable resistance circuit comprises: a third transistor formed of a p-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the first power supply line, and a gate controlled by said current control circuit; and a fourth transistor formed of a p-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the first power supply line, and a gate supplied with said reference voltage.

Claim 88

The electronic circuit as claimed in claim 86, wherein said current control circuit comprises: a fourth transistor formed of an n-channel insulation gate type field effect transistor having a source connected to the second power supply line, a gate supplied with said reference voltage, and a drain; and a resistance element having a first end connected to the drain of the fourth transistor, and a second end connected to the first power supply line, the first end of said resistance element connected to the drain of the fourth transistor being connected to the gate thereof.

Claim 89

The electronic circuit as claimed in claim 86, wherein the current control circuit comprises: a fourth transistor of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate and a drain connected to said gate thereof; and a fifth transistor of an n-channel insulation gate type field effect transistor having a drain connected to the drain of the fourth transistor, a source connected to the second power supply line, and a gate supplied with the reference voltage, the drains of the fourth and fifth transistors being connected to the gate of the third transistor.

Claim 90

The electronic circuit as claimed in claim 86, wherein the current control circuit comprises: a fourth transistor of a p-channel insulation gate type field effect transistor having a source connected to the first power supply line, a gate and a drain; and a fifth transistor of a p-channel insulation gate type field effect transistor having a source connected to the drain of the fourth transistor, a gate supplied with the reference voltage and a drain; and a sixth transistor of an n-channel insulation gate type field effect transistor having a drain connected to the drain of the fifth transistor and the gate of the fourth transistor, a source connected to the second power supply line, and a gate supplied with the reference voltage, the drains of the fifth and sixth transistors being connected to the gate of the third transistor.

Claim 91

The electronic circuit as claimed in claim 86, wherein said current control circuit comprises: a monitor circuit which monitors the current flowing in the variable resistance circuit; and a feedback control circuit which controls a gate voltage of the third transistor so that the current monitored by the monitor circuit is maintained at an approximately constant level.

Claim 92

The electronic circuit as claimed in claim 91, wherein said monitor circuit comprises: a fourth transistor of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the third transistor where m ≧ 1, a source connected to the first power supply line, and a drain; fifth and sixth transistors respectively formed of p-channel insulation gate type field effect transistors respectively having gates having gate widths equal to 1/m of that of the second transistor, drains connected to each other, and gates receiving the reference voltage; and a resistor having a first end connected to the drains of the fifth and sixth transistors, and a second end connected to the second power supply line, said feedback control circuit comprising a differential amplifier circuit including: a first input terminal connected to the drains of the fifth and sixth transistors; a second input terminal supplied with a predetermined voltage; and an output terminal via which an output voltage in phase with a voltage applied to said first input terminal is provided, the output terminal of said feedback control circuit being connected to the gates of said third and fourth transistors.

Claim 93

The electronic circuit as claimed in claim 85, wherein said variable resistance circuit comprises a fifth transistor formed of a p-channel insulation gate type field effect transistor having a drain connected to the sources of the first and second transistors, a source connected to the first power supply line, and a gate controlled by said current control circuit, and wherein said monitor circuit comprises: a sixth transistor formed of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the third transistor where m ≧ 1, a source connected to the first power supply line, and a drain; a seventh transistor formed of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the third transistor, a source connected to the drain of the sixth transistor, and a drain, the reference voltage being applied to the gate of the seventh transistor; an eighth transistor formed of a p-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of that of the third transistor, a source connected to the drain of the sixth transistor, and a drain, the reference voltage being applied to the gate of the eighth transistor; and a ninth transistor formed of an n-channel insulation gate type field effect transistor having a gate having a gate width equal to 1/m of the fourth transistor, a source connected to the second power supply line, and a drain connected to the drain of the eighth transistor, said feedback circuit comprising a differential amplifier circuit comprising: a first input terminal connected to the drains of the seventh and ninth transistors; a second input terminal receiving a constant voltage; and an output terminal outputting a voltage in phase with a voltage applied to the first input terminal, said output terminal of the differential amplifier circuit being connected to the gates of the fifth and sixth transistors.

Claim 94

An electronic circuit connected to a first powers supply line via which a first power supply voltage is supplied, said electronic circuit comprising: a first transistor formed of a p-channel insulation gate field effect transistor having a source connected to a second power supply line via which a second power supply voltage equal to or lower than the first power supply voltage is supplied, a drain connected to an output terminal of the electronic circuit, and a gate supplied with a first signal switchable between a high level corresponding to the second power supply voltage and a low level corresponding to a ground voltage; a second transistor formed of an n-channel insulation gate field effect transistor having a drain connected to the second power supply line, a source connected to the output terminal, and a gate supplied with a second signal switchable between a high level corresponding to said first power supply voltage and a low level corresponding to the ground voltage; and a third transistor formed of an n-channel insulation gate field effect transistor having a drain connected to the output terminal, a source connected to the ground, and a gate supplied with a third signal switchable between a high level corresponding to the first power supply voltage and a second level corresponding to the ground voltage.

Claim 95

The electronic circuit as claimed in claim 94, wherein the second power supply voltage has a lower limit value of 0.84 V.

Claim 96

The electronic circuit as claimed in claim 95, wherein the second power supply voltage has an upper limit value equal to the first power supply voltage.

Claim 97

An electronic circuit comprising: an output control circuit having a power supply terminal connected to a first power supply line via which a first power supply voltage is supplied and outputting first and second signals each switchable between a high level corresponding to the first power supply voltage and a low level corresponding to a ground voltage; a first inverter having a power supply terminal connected to a second power supply line via which a second power supply voltage equal to or lower than the first power supply voltage, an input terminal supplied with the first signal, and an output terminal outputting a signal switchable between a high level corresponding to the second power supply voltage and a low level corresponding to the ground voltage; a second inverter having a power supply terminal connected to the first power supply line, an input terminal supplied with the second signal, and an output terminal outputting a signal switchable between a high level corresponding to the first power supply voltage and a low level corresponding to the ground voltage; a first transistor formed of a p-channel insulation gate type field effect transistor having a drain connected to the second power supply line, a source connected to the output terminal, and a gate connected to the output terminal of the first inverter; a second transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the second power supply line, a source connected to the output terminal, and a gate supplied with the first signal; and a third transistor formed of an n-channel insulation gate type field effect transistor having a drain connected to the output terminal, a source grounded, and a gate connected to the output terminal of the second inverter.

Claim 98

The electronic circuit as claimed in claim 97, wherein the second power supply voltage has a lower limit value of 0.84 V.

Claim 99

The electronic circuit as claimed in claim 98, wherein the second power supply voltage has an upper limit value equal to the first power supply voltage.