CHOPPER-STABILIZED AMPLIFIER AND MAGNETIC FIELD SENSOR

摘要

A chopper stabilized amplifier comprises first and second front-end amplifiers (306, 318), each having a signal input (306a, 318a), a feedback input (306b, 318b) and an output (308, 320), a first switching circuit (310), first and second back-end amplifiers (314, 326) and a feedback path comprising a feedback circuit (328) and a second switching circuit (332). When applying an input signal (302a, 302b) comprising a desired AC component and an unwanted DC offset, both components are amplified by the first and second front-end amplifiers. The amplified components are than applied to the first switching circuit (310) which converts the undesired DC offset component into an undesired high-frequency signal, while the desired AC signal is converted into a desired DC signal. By connecting a suitable low-pass filter at the output of the chopper stabilized amplifier, the undesired high-frequency signal (former DC offset component) is removed.