Successive approximation analog-digital converter, analog-digital conversion method and sensing signal processing device

Abstract

The invention discloses a successive approximation analog-digital converter, a successive approximation analog-digital conversion method and a sensing signal processing device. A first compensation capacitor is additionally arranged on the output end of a first digital-analog converter; compensation voltage to zero drift voltage is applied to the first compensation capacitor through a second digital-analog converter; simultaneously, a second adjustable compensation capacitor is connected between the output end of the existing successive approximation type first digital-analog converter and a zero-voltage end; reference voltage performing analog-digital conversion practically can be adjusted by adjusting the second compensation capacitor; therefore, the zero drift voltage can be compensated in the analog-digital converter; the reference voltage of the analog-digital converter can be adjusted according to requirements; therefore, the residual zero drift voltage of an amplification circuit and the zero drift voltage of devices of the analog-digital converter itself can be adjusted; the reference voltage of the analog-digital converter is adjusted, such that sensors having different sensitivities have same output values in the event of having the same sensing input; and sensing inputs of sensors can be correctly reflected.

Description

technical field [0001] The invention relates to integrated circuit technology, in particular to a successive approximation analog-to-digital converter, an analog-to-digital conversion method and a sensing signal processing device. Background technique [0002] In a general sensor signal conditioning system, such as figure 1 As shown, the output signal of the sensor 1 is amplified by the amplifier circuit 2, and the amplified signal is collected by the analog-to-digital converter 3 (ADC) and converted into a digital signal, and the digital signal is sent to the digital signal processor 4 (DSP) for further processing. data processing. The analog-to-digital converter 3 is an important component in the system, and the successive-approximation analog-to-digital converter is one of the commonly used types. The output value of the analog-to-digital converter 3 reflects the ratio and polarity relationship between the input voltage and its reference voltage. [0003] Due to the di...

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Problems solved by technology

The zero drift voltage will also be amplified by the amplifier circuit 2 and collected by the analog-to-digital converter 3, which will also cause the output of the analog-to-digital converter 3 to be inaccurate

And, due to the existence of the zero drift voltage, the input and output dynamic range of the amplifier circuit 2 will be reduced

In the prior art, a zero-drift voltage adjustment circuit is usually added to the amplifier circuit 2, but due to the limitation of precision, the zero-drift voltage cannot be completely eliminated

Moreover, the amplifying circuit 2 and the analog-to-digital converter 3 themselves also have a zero-drift voltage, if not adjusted, the dynamic range of sensor detection will be reduced

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