Voltage-to-current converter
First Claim
1. A voltage-to-current converter including (1) a differential amplifier having non-inverting and inverting inputs, and (2) associated circuitry for (a) applying an input voltage signal to the converter and (b) deriving from the associated circuitry an output signal current for driving a load;
- a sensing resistor series connected with the load and having opposite first and second terminals for respectively applying voltages to first and second feedback loops;
the loops being respectively associated with the non-inverting and inverting inputs of the differential amplifier;
each of the loops including (a) an intermediate tap connected to a respective input of the differential amplifier, and (b) a first branch including a first resistor connected between the intermediate point associated with the particular feedback loop and the terminal of the sensing resistor associated with the particular feedback loop;
whereby the sensing resistor is connected between the first branches of the first and second feedback loops;
each of the loops also including a second branch having a second resistor connected between the intermediate point associated with the particular feedback loop and an input port of the converter circuit;
the first resistors in the feedback loops have resistance values that are of the same order of magnitude and are substantially higher than the resistance values of the sensing resistor and the load;
whereby the current adapted to flow across the sensing resistor is an output current signal directly proportional to the input voltage signal applied between input ports of the second branches of the first and the second feedback loops.
4 Assignments
0 Petitions
Accused Products
Abstract
A load responds to a voltage-to-current converter including a differential amplifier. A sensing resistor is series connected with the load and first and second feedback resistors, respectively included in first and second voltage dividers having taps connected to non-inverting and inverting inputs of the amplifier. One divider is connected between a first terminal of the sensor resistor and one voltage responsive input terminal of the converter. Another divider is connected between the second terminal of the sensor resistor and a second converter input terminal, that can be grounded or voltage responsive. The feedback resistors have the same value that is much greater than the sensor resistor value. The first divider can be connected to the first or second terminal of the sensor resistor and vice versa for the second divider.
13 Citations
33 Claims
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1. A voltage-to-current converter including (1) a differential amplifier having non-inverting and inverting inputs, and (2) associated circuitry for (a) applying an input voltage signal to the converter and (b) deriving from the associated circuitry an output signal current for driving a load;
- a sensing resistor series connected with the load and having opposite first and second terminals for respectively applying voltages to first and second feedback loops;
the loops being respectively associated with the non-inverting and inverting inputs of the differential amplifier;
each of the loops including (a) an intermediate tap connected to a respective input of the differential amplifier, and (b) a first branch including a first resistor connected between the intermediate point associated with the particular feedback loop and the terminal of the sensing resistor associated with the particular feedback loop;
whereby the sensing resistor is connected between the first branches of the first and second feedback loops;
each of the loops also including a second branch having a second resistor connected between the intermediate point associated with the particular feedback loop and an input port of the converter circuit;
the first resistors in the feedback loops have resistance values that are of the same order of magnitude and are substantially higher than the resistance values of the sensing resistor and the load;
whereby the current adapted to flow across the sensing resistor is an output current signal directly proportional to the input voltage signal applied between input ports of the second branches of the first and the second feedback loops. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a sensing resistor series connected with the load and having opposite first and second terminals for respectively applying voltages to first and second feedback loops;
- 10. The converter of claim 10, further including a ramp signal generator for selectively applying to the input port of one of the second branches of one of said first and second feedback loops a ramp signal for gradually reducing said output current signal.
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13. A circuit comprising an output terminal for connection to a load;
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
first and second voltage dividers;
a sensing resistor connected between the circuit output terminal and the amplifier arrangement output terminal;
a first feedback path connected between the output terminal of the amplifier arrangement and one of the input terminals of the amplifier arrangement;
a second feedback path connected between the output terminal of the circuit and the other input terminal of the amplifier arrangement;
the first feedback circuit being included in a first resistive voltage divider connected between the circuit input terminal and the output terminal of the amplifier arrangement;
the second feedback circuit being included in a second resistive voltage divider connected between a further terminal and the circuit output terminal;
the first voltage divider having a first tap connected to drive the first input terminal of the amplifier arrangement;
the second voltage divider having a second tap connected to drive the second input terminal of the amplifier arrangement;
the voltage dividers having voltage division factors and the sensing resistor having a value for causing the current flowing through the circuit output terminal into the load to be directly proportional to the difference in the voltages at the circuit input terminal and the further terminal;
the resistance of the first voltage divider between the output and first input terminals of the amplifier arrangement and the resistance of the second voltage divider between the circuit output terminal and the second input terminal of the amplifier arrangement being on the same order of magnitude and much greater than the resistance of the sensor resistance. - View Dependent Claims (14, 15, 16)
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
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17. A circuit comprising an output terminal for connection to a load;
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
first and second voltage dividers;
a sensing resistor connected between the circuit output terminal and the amplifier arrangement output terminal;
a first feedback path connected between the output terminal of the amplifier arrangement and one of the input terminals of the amplifier arrangement;
a second feedback path connected between the output terminal of the circuit and the other input terminal of the amplifier arrangement;
the first feedback circuit being included in a first resistive voltage divider connected between the circuit input terminal and the output terminal of the amplifier arrangement;
the second feedback circuit being included in a second resistive voltage divider connected between a further terminal and the circuit output terminal;
the first voltage divider having a first tap connected to drive the first input terminal of the amplifier arrangement;
the second voltage divider having a second tap connected to drive the second input terminal of the amplifier arrangement;
the voltage dividers having voltage division factors and the sensing resistor having a value for causing the current flowing through the circuit output terminal into the load to be directly proportional to the difference in the voltages at the circuit input terminal and the further terminal;
the first and second input terminals being respectively the non-inverting and inverting input terminals of the amplifier arrangement. - View Dependent Claims (18, 19, 20, 21, 22)
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
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23. A circuit comprising an output terminal for connection to a load;
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
first and second voltage dividers;
a sensing resistor connected between the circuit output terminal and the amplifier arrangement output terminal;
a first feedback path connected between the output terminal of the amplifier arrangement and one of the input terminals of the amplifier arrangement;
a second feedback path connected between the output terminal of the circuit and the other input terminal of the amplifier arrangement;
the first feedback circuit being included in a first resistive voltage divider connected between the circuit input terminal and the output terminal of the amplifier arrangement;
the second feedback circuit being included in a second resistive voltage divider connected between a further terminal and the circuit output terminal;
the first voltage divider having a first tap connected to drive the first input terminal of the amplifier arrangement;
the second voltage divider having a second tap connected to drive the second input terminal of the amplifier arrangement;
the voltage dividers having voltage division factors and the sensing resistor having a value for causing the current flowing through the circuit output terminal into the load to be directly proportional to the difference in the voltages at the circuit input terminal and the further terminal;
the laser diode having first and second electrodes respectively connected to be responsive to the voltage of a non-grounded terminal of a DC voltage source and the circuit output terminal, the DC voltage source polarity and the laser diode polarity being such that DC current is adapted to flow between the DC voltage source ungrounded terminal and the circuit output terminal via the laser diode. - View Dependent Claims (24, 25, 26)
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
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27. A circuit comprising an output terminal for connection to a load;
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
first and second voltage dividers;
a sensing resistor connected between the circuit output terminal and the amplifier arrangement output terminal;
a first feedback path connected between the output terminal of the amplifier arrangement and one of the input terminals of the amplifier arrangement;
a second feedback path connected between the output terminal of the circuit and the other input terminal of the amplifier arrangement;
the first feedback circuit being included in a first resistive voltage divider connected between the circuit input terminal and the output terminal of the amplifier arrangement;
the second feedback circuit being included in a second resistive voltage divider connected between a further terminal and the circuit output terminal;
the first voltage divider having a first tap connected to drive the first input terminal of the amplifier arrangement;
the second voltage divider having a second tap connected to drive the second input terminal of the amplifier arrangement;
the voltage dividers having voltage division factors and the sensing resistor having a value for causing the current flowing through the circuit output terminal into the load to be directly proportional to the difference in the voltages at the circuit input terminal and the further terminal;
the resistance (R1) of the first voltage divider between the output and first input terminal of the amplifier arrangement being of the same order of magnitude as the resistance of the second voltage divider between the circuit output terminal and the second terminal of the amplifier arrangement, the resistance (R2) of the first voltage divider between the first input terminal of the amplifier arrangement and the circuit input terminal being of the same order of magnitude as the resistance between the second input terminal of the amplifier arrangement. - View Dependent Claims (28, 29, 30, 31, 32, 33)
- an amplifier arrangement having an output terminal and inverting and non-inverting input terminals, the amplifier arrangement being arranged for deriving at the output terminal thereof an output voltage having a magnitude directly proportional to the difference in the voltages at the inverting and non-inverting output terminals;
Specification