Low offset current sensing circuit based on switched-capacitor

Abstract

Presents a low offset current sensing circuit based on switched-capacitor, in which resistance sensing technique is used. Under the control of clock switch, the switched-capacitor integrator could feed the operational amplifier offset voltage back to major circuit as a negative feedback regulator periodically to reduce the influence from the offset to the output. It is shown in the HSPICE simulation that the whole offset voltage would be lowered down to the level below 0.08 percent through the circuit. Furthermore, the circuit has already been applied in a reality 16-channel power management chip based on 0.36um process and proved to be efficient.