Diode and varistor simulator
AssigneeGTE Automatic Electric Labs Inc.
InventorCarl B. Branson
Life of this patent
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Abstract
An active circuit for modeling desireable diode and varistor characteristics in signal limiting circuits. The circuit includes a resistor arrangement for setting the desireable threshold voltage to an operational amplifier, the other input of which is connected to a reference voltage level. The amplifier output is tied back to the circuit input and to one input of a second amplifier. A second input is connected to the reference voltage level to act as a current sensor to vary the threshold level in response to the current flow.
Claims3
A two terminal varistor simulator circuit having an input and a reference terminal comprising a first and a second diode simulator circuit each further comprising:
- a resistive voltage divider having a first end terminal connected to said input terminal and a second end terminal and an adjustable tap terminal,
- a first and a second operational amplifier each having a first and a second input means and an output means,
- a first resistor having a first and a second terminal,
- means connecting said resistive voltage divider tap terminal to said first input means of said first operational amplifier operating in an inverting mode to thereby select a voltage reference, and said second end terminal to said first resistor first terminal,
- said first operational amplifier second terminal and said first resistor second terminal connected to said reference terminal,
- a diode and a second resistor connected in series and between said input terminal and said first operational amplifier output terminal to limit said operational amplifier to half wave operation,
- said second operational amplifier output terminal connected to said resistive voltage divider second terminal,
- a variable resistor connected across said second operational amplifier first input terminal and said output terminal to adjustably set the requisite gain,
- said first operational amplifier output terminal further connected to said second operational amplifier second input terminal,
- said second operational amplifier first input terminal connected to the junction of said diode and second resistor placing said second operational amplifier inputs across said second resistor to thereby respond to the current flow of said first operational amplifier.
Dependencies are inferred from the claim text.