Electronic switch for an operational amplifier circuit

Claim 2

An electronic circuit for controllably supplying current to a load, comprising: An amplifier having an input, an output and at least one power supply line, a switching element connected in the output line of said amplifier for connecting said output line to a fixed potential, whereby current flowing in said at least one power supply line varies in proportion to a signal at the amplifier input when the switching element is turned on while substantially no current flows in said at least one power supply line when the switching element is turned off, and means for sensing current flow in the voltage supply line and driving said load with a current proportional thereto.

Claim 3

An optical scanning instrument, comprising a point radiation detector which generates a time varying electrical signal in proportion to the intensity of radiation incident thereon, a rotating mirror system for scanning the horizontal aspects of an object radiation field image across said point detector, said horizontal scanning system including a motor for driving said system at substantially a uniform angular velocity, an angularly rotatable mirror positioned to scan the vertical aspects of the object radiation field image across said detector, a torque motor for angularly rotating said vertical scanning mirror, an electronic circuit for synthesizing a voltage function for driving said torque motor, thereby to drive said vertical scanning mirror in accordance with said function, an amplifier having an input, an output and at least one power supply line, said amplifier input being connected to the voltage waveform synthesized by said electronic circuit, a switching element positioned in the output circuit of said amplifier for connecting its output to a fixed potential when the switching element is turned on and alternatively allowing the amplifier to float when the switching element is turned off, whereby current in said at least one power supply line to the amplifier varies in proportion to the vertical mirror driving signal at its input when the switching element is on and whereby current in said at least one power supply line is substantially zero when the switching element is turned to its off condition, and means for sensing current flow in said amplifier power supply line and for driving said torque motor in response thereto.

Claim 4

An optical scanning instrument, comprising a point radiation detector which generates a time varying electrical signal in proportion to the intensity of radiation incident thereon, a rotating mirror system for scanning the horizontal aspects of an object radiation field image across said point detector, said horizontal scanning system including a motor for driving said system at substantially a uniform angular velocity, an angularly rotatable mirror positioned to scan the vertical aspects of the object radiation field image across said detector, a torque motor for angularly rotating said vertical scanning mirror, an electronic circuit for synthesizing a voltage function for driving said torque motor, thereby to drive said vertical scanning mirror in accordance with said function, an amplifier having an input, an output and at least one power supply line, said amplifier input being connected to the voltage waveform synthesized by said electronic circuit, a switching element positioned in the output circuit of said amplifier for connecting its output to a fixed potential when the switching element is turned on and alternatively allowing the amplifier to float when the switching element is turned off, whereby current in said at least one power supply line to the amplifier varies in proportion to the vertical mirror driving signal at its input when the switching element is on and whereby current in said at least one power supply line is substantially zero when the switching element is turned to its off condition, and means for sensing current flow in said amplifier power supply line and for driving said torque motor in response thereto.

Claim 5

The optical scanning instrument according to claim 2 wherein the switching element includes; means for sensing when electrical energy is first applied to the horizontal scanning rotating mirror assembly driving motor, means for holding the switching element in an off state for a period of time at least as great as that required for the horizontal scanning assembly driving motor to bring the horizontal scanning assembly up to its substantially uniform angular velocity and for switching the switching element to its on state after said period of time, whereby the vertical scanning mirror torque motor is energized by said amplifier means.

Claim 6

An electronic circuit for controllably supplying current to a two terminal load, comprising, an operational amplifier having an inverting input, a non-inverting input, an output, a positive voltage supply terminal and a negative voltage supply terminal, a resistor connected between the positive voltage amplifier supply terminal and a positive voltage source, a resistor connected between the negative voltage amplifier supply terminal and a negative voltage source, a switching element connected to the output of said operational amplifier for controllable connection thereof to a reference potential, means sensing a voltage drop across at least one of said positive voltage circuit or negative voltage circuit resistors for supplying current to one terminal of said load that is proportional to the voltage sensed, a resistance connected between a fixed potential and the other terminal of said load, said other terminal of the load also being connected to the inverting input of said amplifier, whereby a load current proportional to voltage at the non-inverting amplifier input is supplied to said load and whereby the switching element in the amplifier output circuit will shut off current to the load.

Claim 7

An electronic circuit for controllably supplying current to a two terminal load, comprising, an operational amplifier having an inverting input, a non-inverting input, an output, a positive voltage supply terminal and a negative voltage supply terminal, a resistor connected between the positive voltage amplifier supply terminal and a positive voltage source, a resistor connected between the negative voltage amplifier supply terminal and a negative voltage source, a switching element connected to the output of said operational amplifier for controllable connection thereof to a reference potential, means sensing a voltage drop across at least one of said positive voltage circuit or negative voltage circuit resistors for supplying current to one terminal of said load that is proportional to the voltage sensed, a resistance connected between a fixed potential and the other terminal of said load, said other terminal of the load also being connected to the inverting input of said amplifier, whereby a load current proportional to voltage at the non-inverting amplifier input is supplied to said load and whereby the switching element in the amplifier output circuit will shut off current to the load.

Claim 8

An electronic circuit according to claim 4 wherein the switching element includes a three terminal semiconductor device having a control terminal whose voltage determines whether the switching element is in its on state or in its off state.

Claim 9

An electronic circuit according to claim 5 additionally comprising an electronic circuit connected to the control terminal of the semiconductor switching element for controlling whether said switch is in its on state or its off state, said circuit including: means for turning on said semiconductor switch after a predetermined delay from the time that a change in a voltage from a first level to a second level is sensed, and means for turning the semiconductor switching device into its off state substantially instantaneously with detection of a change in said voltage level from its second level back to its first level.

Claim 10

An electronic switching circuit for changing an output between two electrical levels in response to an external voltage changing between high and low levels, comprising: a capacitor normally connected to be charged to a voltage proportional to the external voltage level through a series charging resistance, means sensing the voltage across the capacitor for driving said circuit output to one level when the voltage is below a certain threshold and to a second output level when the capacitor voltage is equal to or greater than said threshold voltage level, and means for connecting a discharge resistance across said capacitor when the external voltage is at a low level, said discharge resistance having a value significantly less than said series charging resistance.

Claim 11

An electronic switching circuit for changing an output between two electrical levels in response to an external voltage changing between high and low levels, comprising: a capacitor normally connected to be charged to a voltage proportional to the external voltage level through a series charging resistance, means sensing the voltage across the capacitor for driving said circuit output to one level when the voltage is below a certain threshold and to a second output level when the capacitor voltage is equal to or greater than said threshold voltage level, and means for connecting a discharge resistance across said capacitor when the external voltage is at a low level, said discharge resistance having a value significantly less than said series charging resistance.

Claim 12

An electronic circuit for controllably supplying current to a load, comprising: an amplifier having an input, an output and at least one power supply line, a signal source connected to said amplifier input, a power supply connected to said at least one power supply line, a fixed potential terminal, a switching element connected between the amplifier output and said fixed potential terminal, said switching element having conductive and non-conductive states in response to a control signal, means independent of the amplifier input signal level for developing said control signal, and means for sensing current flow in the voltage supply line and driving said load with a current proportional thereto, whereby current to said load is turned off when said control signal causes the switching element to go into its non-conductive state.

Claim 13

An electronic circuit for controllably supplying current to a load, comprising: an amplifier having an input, an output and at least one power supply line, a signal source connected to said amplifier input, a power supply connected to said at least one power supply line, a fixed potential terminal, a switching element connected between the amplifier output and said fixed potential terminal, said switching element having conductive and non-conductive states in response to a control signal, means independent of the amplifier input signal level for developing said control signal, and means for sensing current flow in the voltage supply line and driving said load with a current proportional thereto, whereby current to said load is turned off when said control signal causes the switching element to go into its non-conductive state.

Claim 14

The electronic circuit of claim 8 wherein said control signal developing means includes means responsive to a power supply level to said signal source for holding the switching element in its non-conductive state for a period of time after power is first applied to the signal source, whereby the load does not receive current during a warm-up period of said signal source.

Claim 15

The electronic circuit of claim 9 wherein said control signal developing means additionally includes means responsive to said power supply level of the signal source for rapidly causing the switching element to become non-conductive after power is first removed from the signal source, whereby the load does not receive current during transients within the signal source that may follow removal of power therefrom.