Programmable gain amplifier, chip and electronic equipment

The embodiment of the utility model provides a programmable gain amplifier which comprises an operational amplifier which comprises an input end and an output end; the at least one signal input module is connected to the input end of the operational amplifier and is used for providing a corresponding input signal according to the input analog signal and inputting the input signal to the operational amplifier; the at least one resistance switch module is connected between the input end and the output end of the operational amplifier, and the resistance switch module comprises a first switch circuit connected with the input end of the operational amplifier and a first resistor connected with the first switch circuit; through the above mode, the first switch circuit is added in the resistance switch module, the resistance of the resistance switch module is increased, and the problems of gain error increase and poor waveform linearity of the programmable gain amplifier caused by conduction impedance change of a s