Temperature compensation of voltage controlled resistor

Claim 2

A temperature compensating circuit for a field effect voltage controlled resistor having a temperature sensitive channel of semiconductor material and a gate forming a PN junction with said channel; said circuit comprising: means for developing a control voltage which varies with a first voltage drop across the emitter-base junction of a bipolar transistor subjected to substantially the same temperature conditions as said voltage controlled resistor and also varies with a second voltage drop across a temperature responsive resistor also subjected to said temperature conditions; said emitter-base junction having a contact potential substantially the same as the contact potential of said junction of said voltage controlled resistor and said temperature responsive resistor having substantially the same voltage sensitivity as said channel; and means for applying said control voltage as part of a reverse bias potential between said gate and said channel so as to cause said first voltage drop to compensate for changes in said contact potential of said voltage controlled resistor and said second voltage drop to compensate for changes in resistance of said channel produced by changes in temperature of said voltage controlled resistor.

Claim 3

A temperature compensating circuit for a field effect voltage controlled resistor having a temperature sensitive channel of semiconductor material and a gate forming a PN junction with said channel; said circuit comprising: means for developing a control voltage which varies with a first voltage drop across the emitter-base junction of a bipolar transistor subjected to substantially the same temperature conditions as said voltage controlled resistor and also varies with a second voltage drop across a temperature responsive resistor also subjected to said temperature conditions; said emitter-base junction having a contact potential substantially the same as the contact potential of said junction of said voltage controlled resistor and said temperature responsive resistor having substantially the same voltage sensitivity as said channel; and means for applying said control voltage as part of a reverse bias potential between said gate and said channel so as to cause said first voltage drop to compensate for changes in said contact potential of said voltage controlled resistor and said second voltage drop to compensate for changes in resistance of said channel produced by changes in temperature of said voltage controlled resistor.

Claim 4

A temperature compensating circuit for a field effect voltage controlled resistor having a temperature sensitive channel of semiconductor material and a gate forming a PN junction with said channel; said circuit comprising: means for developing a control voltage which varies with a first voltage drop across the emitter-base junction of a bipolar transistor subjected to substantially the same temperature conditions as said voltage controlled resistor and also varies with a second voltage drop across a temperature responsive resistor also subjected to said temperature conditions; said emitter-base junction having a contact potential substantially the same as the contact potential of said junction of said voltage controlled resistor and said temperature responsive resistor having substantially the same voltage sensitivity as said channel; and means for applying said control voltage as part of a reverse bias potential between said gate and said channel so as to cause said first voltage drop to compensate for changes in said contact potential of said voltage controlled resistor and said second voltage drop to compensate for changes in resistance of said channel produced by changes in temperature of said voltage controlled resistor.

Claim 5

A temperature compensating circuit for a field effect voltage controlled resistor having a temperature sensitive channel of semiconductor material and a gate forming a PN junction with said channel; said circuit comprising: means for developing a control voltage which varies with a voltage drop across the emitter-base junction of a bipolar transistor subjected to substantially the same temperature conditions as said voltage controlled resistor and also varies with voltage drop across a temperature responsive resistor also subjected to said temperature conditions; said emitter-base junction having a contact potential substantially the same as the contact potential of said junction of said voltage controlled resistor and said temperature responsive resistor having substantially the same voltage sensitivity as said channel; means for applying said control voltage as part of a reverse bias potential between said gate and said channel so as to compensate for changes in resistance of said channel produced by changes in temperature of said voltage controlled resistor; said circuit means includes means connecting the emitter-collector circuit of said bipolar transiStor in a series circuit with said temperature responsive resistor and also connecting said series circuit in series with a current source and means for connecting said series circuit between said gate and said channel.

Claim 6

A temperature compensating circuit for a field effect voltage controlled resistor having a temperature sensitive channel of semiconductor material and a gate forming a PN junction with said channel; said circuit comprising: means for developing a control voltage which varies with a voltage drop across the emitter-base junction of a bipolar transistor subjected to substantially the same temperature conditions as said voltage controlled resistor and also varies with voltage drop across a temperature responsive resistor also subjected to said temperature conditions; said emitter-base junction having a contact potential substantially the same as the contact potential of said junction of said voltage controlled resistor and said temperature responsive resistor having substantially the same voltage sensitivity as said channel; means for applying said control voltage as part of a reverse bias potential between said gate and said channel so as to compensate for changes in resistance of said channel produced by changes in temperature of said voltage controlled resistor; said circuit means includes means connecting the emitter-collector circuit of said bipolar transiStor in a series circuit with said temperature responsive resistor and also connecting said series circuit in series with a current source and means for connecting said series circuit between said gate and said channel.

Claim 7

The temperature compensating circuit of claim 2 which also includes: means for applying an adjustable forward bias between the base and emitter of said bipolar transistor to adjust the voltage between said collector and emitter of said bipolar transistor to thereby adjust the compensating effect of said control voltage on the resistance of said channel.

Claim 8

The temperature compensating circuit of claim 3 which also includes: means for adjusting said current source to adjust the current through said series circuit and the voltage drop across said temperature responsive circuit to thereby adjust the resistance of said channel.

Claim 9

The temperature compensating circuit of claim 2 in which the channel of said voltage controlled resistor has its gate arranged symmetrically with respect to its channel so as to cause the control of the resistance of said channel by a reverse bias potential between said gate and channel to be independent of the direction of current flow through said channel and in which said channel is connected between the emitters of a pair of bipolar transistors forming part of a paraphase amplifier having said emitters of said pair of transistors each connected through a current source to a source of potential.

Claim 10

The temperature compensation circuit of claim 5 in which: said control voltage is effectively applied between the gate of said voltage controlled resistor and the midpoint of a resistance circuit connected between the ends of said channel of said voltage controlled resistor.