Programmable gain amplifier capable of adjusting signals

Abstract

The invention provides a programmable gain amplifier capable of adjusting signals. The programmable gain amplifier adopts a PGA circuit and comprises: an operational amplifier circuit, an input end, an output end, a first feedback capacitor, a second feedback capacitor, a first switch and a second switch, wherein the first feedback capacitor is connected between the output end of a reserve input end of the operational amplifier circuit, one end of the second feedback capacitor is connected with the reserve input end of the operational amplifier circuit, and the other end of the second feedback capacitor is separately connected with the output end and a reference voltage through the first switch and the second switch. The programmable gain amplifier reduces the number of the used capacitors, thereby saving the area; the number of the input voltages is decreased, thereby simplifying the circuit design; meanwhile the area, the power consumption and the noise are reduced; the feedback coefficient of the PGA circuit is increased, the design difficulty of the operational amplifier circuit is reduced, and meanwhile the power consumption is reduced; and the programmable gain amplifier can be configured to be the PGA circuit that only has an amplification function, thereby being more flexible.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a signal-adjustable and programmable gain amplifier. Background technique [0002] Programmable Gain Amplifier, referred to as PGA, is an analog amplifier circuit that amplifies the input analog voltage signal by a set multiple and then outputs it. The amplification factor is determined by the ratio of the sampling capacitor to the feedback capacitor. The PGA circuit implemented by the switched capacitor method is fully compatible with the current standard CMOS process technology, so it is widely used in the current standard CMOS chip to amplify the analog voltage signal. [0003] figure 1 It is a typical PGA circuit schematic diagram. After the analog voltage signal is amplified by the set multiple after the PGA circuit, it is output to the analog-to-digital conversion ADC circuit. After being converted into a digital signal by the ADC circuit, it is output to the d...

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Problems solved by technology

[0008] image 3 The circuit shown can achieve signal amplification and regulation, but it has several obvious disadvantages: 1. Compared with the traditional PGA, a capacitor Cos is added, which increases the area; 2. Two reference voltages Vos1 and Vos2 are added, The complexity of the circuit has been increased, and t

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