Mos tube switch circuit diagram

In the figure, the positive power of the battery is connected to the source of pin 2 of field effect transistor Q1 through switch S1. Since Q1 is a P-channel tube, its pin 1 gate provides a positive potential voltage through the R20 resistor, so it cannot be powered and the voltage cannot be Continue to pass, the input pin of the 3v voltage stabilizing IC does not get voltage, so it cannot work or turn on!

At this time, if we press the SW1 power-on button, positive electricity is added to the base of transistor Q2 through the button, R11, R23, and D4. The base of transistor Q2 gets a positive potential, and the transistor is turned on (when talking about the transistor earlier) (already mentioned), since the emitter of the transistor is directly connected to the ground, the conduction of the transistor Q2 is equivalent to the gate of Q1 being directly connected to the ground. The voltage applied to it through the R20 resistor directly enters the ground, and the gate of Q1 switches from high to high. The potential becomes low, Q1 is turned on and the power is added from Q1 to the input pin of the 3v voltage stabilizing IC. The 3v voltage stabilizing IC is the 3v working voltage vcc that U1 outputs to supply to the main control. The main control clears it to 0 through reset, and reads Take a series of actions such as firmware program detection, input a control voltage to PWR_ON, and then send it to the base of Q2 through R24 and R13 to divide the voltage, keeping Q2 in the conducting state, even if you release the power button to disconnect the base of Q1 At this time, the control voltage sent by the master is maintained, so Q2 can always be in the on state, and Q1 can continuously provide working voltage to the 3v voltage stabilizing IC!

SW1 also divides the voltage of the two resistors R11 and R30 to send control signals of different lengths and times to the main control PLAYON pin. The main control identifies play, pause, power on, and shutdown through the firmware and outputs different results to the corresponding control points to achieve different working states!