Chopping stable instrument amplifier

Abstract

The invention relates to a chopping stable instrument amplifier, comprising a low-gain high-frequency closed circuit, a high-gain low-frequency closed circuit, and a residual RRL (Ripple Reduction Loop); wherein the low-gain high-frequency closed circuit consists of an operational amplifier Gm3 and an operational amplifier Gm4; the high-gain low-frequency closed circuit consists of a chopper CH1,an operational amplifier Gm1, a chopper CH2, an operational amplifier Gm2, a switched capacitor notch filter NOTCH and the operational amplifier Gm4; and the residual RRL consists of induction capacitors C41 and C42, a cascode buffer Cascade Buffer 1, a chopper CH3, a cascade buffer Cascade Buffer 2, an integrating capacitor Cint, and an operational amplifier Gm5. The chopping stable instrument amplifier of the invention has the beneficial effects that: through the low-gain high-frequency closed circuit and the high-gain low-frequency closed circuit, offset voltage and 1 / f noise of a circuit can be effectively eliminated, and bandwidth of the circuit can be greatly raised, on that basis the RRL is introduced to effectively reduce the amplitude of the ripple output by the circuit, thus thewhole circuit noise is optimized, low-noise output is achieved, thereby improving circuit accuracy.

Description

technical field [0001] The present invention relates to a chopper stabilized instrumentation amplifier. Background technique [0002] With the rapid development of the Internet of Things in recent years, more and more practical applications require low-frequency signal measurement devices, such as electric eye (EOG), electroencephalogram (EEG), electrocardiogram (ECG) and electromyography (EMG) and other biological signals , all need sensors to convert these biological signals into electrical signals for detection. These biological signals are very weak, as small as tens of μV to tens of mV, and the frequency range provided is only from DC to hundreds of Hz. At such a low frequency, flicker noise (1 / f noise ) and offset voltage and other non-ideal factors, this non-ideal factor has been proved to be quite unfavorable to the signal acquisition, so it is necessary to adopt corresponding technology to eliminate these non-ideal factors, and at the same time deal with the weak b...

AI Technical Summary

Problems solved by technology

Due to the trade-off between residual offset and residual ripple amplitude in the traditional chopper-stabilized structure, in order to solve this problem, a ripple reduction loop RRL (Ripple reduction loop) is introduced to achieve lower residual offset performance while reducing the output Ripple amplitude

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