Provided by the present application are a differential circuit, a capacitance detection circuit and a touch detection device, which may reduce the noise of a differential circuit, improving the signal to noise ratio of an output signal, and which may improve the accuracy of capacitance detection when the differential circuit is applied to the capacitance detection circuit. The differential circuit comprises a front end circuit and a processing circuit; the front end circuit comprises a control circuit and a PGA circuit; the control circuit is connected to a power supply, two capacitors and the PGA circuit, and is used for controlling the power supply to charge the two capacitors, controlling the two capacitors to discharge power to the PGA circuit in a first stage, and controlling the PGA circuit to charge the two capacitors in a second stage; the PGA circuit is used for respectively converting capacitance signals of the two capacitors into voltage signals and differencing the same in the first and second stages to obtain difference signals of corresponding voltages of the two capacitors in the first and second stages; the processing circuit is connected to the front end circuit, being used for determining target difference signals of corresponding voltages of the two capacitors according to the difference signals outputted by the front end circuit in the first and second stages.
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