Overall circuit module design of wireless charging system

　　The process of receiving electrical energy from an external circuit and converting it into chemical energy of the battery. After the battery consumes its energy through discharge, it can be restored through charging and discharged again, forming a charge-discharge cycle. Generally, it is charged with direct current (also with asymmetric alternating current or pulse current). Different charging methods are used in different situations, such as constant current charging, constant voltage charging, floating charging, trickle charging, rapid charging or a combination of these methods.

　　Circuit principle: 892051 is used to detect the negative slope of charging, MCI4066 determines which battery to sample, and U3A-C forms a charging constant current source. Q3 and TL431 form a constant current source to charge C5. When the voltage of C5 rises to the sampling voltage, U3D flips to generate an interrupt INT0 to stop the internal timer of 2051. The timer gets the voltage. When the voltage drops continuously, Q4, Q5 or Q6 is saturated to stop charging.