Precision voltage clamp with very low temperature drift

摘要

A precision voltage clamp is provided that displays virtually no temperature dependence, and maintains a clamp voltage that varies by about 1 my for input voltages ranging from the onset of clamping to several volts above this input. In particular, a current mirror is used to ensure that the current densities in the clamping transistor, and the bias correcting transistor, are very close to equal once the clamping action begins. A small current may be injected into the programming side of the mirror which will turn on the mirror and the biasing transistor, making it much easier for the clamp to clamp and settle.