Semiconductor operational amplifier device and semiconductor sensing device

Abstract

Semiconductor operational amplifier devices and semiconductor sensing devices are described herein. The semiconductor operational amplifier device includes: a main operational amplifier circuit including a first BJT and a second BJT configured to receive a differential input signal; and an input current compensation circuit including a third BJT Transistors, clamped op amps, and current mirrors. The clamping operational amplifier is configured to operate the third BJT at the same bias as the first BJT and the second BJT. A current mirror is coupled between the first node and the bases of the first bipolar junction transistor, the second bipolar junction transistor and the third bipolar junction transistor, and the current mirror is configured to feed the first bipolar junction transistor respectively The bases of the junction transistor, the second bipolar junction transistor and the third bipolar junction transistor provide bias currents proportional to each other. This semiconductor operational amplifier device realizes low-noise amplification of weak input signals with high precision.

Description

technical field [0001] Embodiments of the present disclosure relate generally to semiconductor devices, and more particularly to low input current low noise operational amplifier devices and sensing devices under a BiCMOS process. Background technique [0002] High-precision sensors usually need to process weak current signals. High-precision sensors include, for example, optical observation sensors, which require a current-to-voltage converter to amplify the weak current signal of the photodiode into a voltage signal that can be processed later. Current-to-voltage converters typically consist of low-noise op amps with low input leakage or input bias current and resistors. [0003] In CMOS technology, low-noise operational amplifiers are usually implemented using chopper technology (Chopper) or auto-zero technology (AZ). However, both techniques produce output ripple and introduce input leakage current at the input terminals of the op amp. Input leakage current degrades p...

AI Technical Summary

Problems solved by technology

In this scheme, the matching degree of the mirror compensation current is easily changed with the input common mode of the operational amplifier and the power supply voltage, resulting in a change in the input residual leakage current

In addition, this scheme uses a CMOS current mirror to compensate the input leakage current of the op amp, which will deteriorate the noise specification of the op amp

Images