Pop-free headset detection circuit

A pop-free headset detection circuit, used for detecting and determining the type of a headset, comprising:

• a socket unit, having a first pin, a second pin, a third pin, a fourth pin, a power supply pin and a driving pin;
• a first operational amplifier, having an output end connected to the first pin, having an inverting input end connected to a left-channel audio source and having a non-inverting input end receive a first reference voltage;
• a second operational amplifier, having an output end connected to the second pin, having an inverting input end connected to a right-channel audio source and having a non-inverting input end receive a second reference voltage;
• and
• a detection and control circuit, connected to the third pin, the fourth pin and the driving pin;
• wherein the detection and control circuit is further connected to an enable end of the first operational amplifier and an enable end of the second operational amplifier, and when a headset plug of the headset is plugged into the socket unit, the detection and control circuit controls the first operational amplifier and the second operational amplifier to be in a Hi-Z state and determines the type of the headset according to the voltage at the fourth pin;
• wherein the first pin is a TIP pin, the second pin is a RING1 pin, the third pin is a RING2 pin and the fourth pin is a SLEEVE pin.