Patent ID: 6040737
Filing Date: 2000-03-21
Classification: H03K

Abstract:
A circuit for compensating an integrated circuit chip to account for variations in process and operating conditions, the circuit comprising:a resistor having a first end coupled to a first voltage, and having a second end for supplying a control voltage;a transistor having a first port coupled to the second end of the resistor, a second port coupled to a second voltage, and a third port for controlling the amplitude of a current flowing between the first and second ports;an operational amplifier having a first input coupled to the second end of the resistor for receiving the control voltage, a second input coupled to a reference voltage between the first and second voltages, and an output coupled to the third port of the transistor for providing a compensation voltage thereto, with the compensation voltage maintaining said current in the transistor at a substantially constant amplitude;a second transistor having a fourth port coupled to the output of the operational amplifier for receiving the compensation voltage, a fifth port coupled to the second voltage, and a sixth port for supplying a flow of current at an amplitude responsive to the compensation voltage; andcircuitry having an effective resistance, the circuitry providing a third end and a fourth end, the third end coupled to the sixth port of the second transistor for receiving the flow of current, the fourth end coupled to the first voltage for supplying said flow of current thereto, with the voltage drop across the circuitry providing a second compensation voltage at the third end of the circuitry.