Circuit for auto-zeroing a high impedance CMOS current driver

摘要

An improved auto-zeroing circuit for reducing offset currents from high impedance CMOS current drivers. The Auto zero circuit of the present invention contains means to disconnect the output of the current driver from its low impedance load, means to substantially simultaneously connect a capacitor to the output of the current driver, and means to use the output voltage of the current sources during the zeroing mode to adjust the voltage on the capacitor. The capacitor voltage is then used to adjust either of the two output current sources to reduce the offset currents.