This solution uses the high-performance current-mode PWM controller EG1253 as the main control chip, which greatly improves cost-effectiveness compared to the traditional UC3842 solution, mainly focusing on the following advantages: significantly reduced number of external components; external NTC temperature protection function; optocoupler open-circuit protection; light-load frequency reduction and burst mode; built-in slope compensation; low quiescent current, etc. The three-stage charging management chip uses EG4321, which integrates constant voltage, constant current, and lamp control modules, as well as dual-LED charge indicators and fan drive circuits.

The LLC half bridge resonant power supply scheme based on EG6599 and EG4328 chips, with an input voltage of AC 220 ± 10%, can achieve intelligent charging management of 60V12A lead-acid batteries (also customizable as lithium batteries), with multiple protection functions, charging status indication, and heat dissipation design. The circuit parameters are set in a specific way, suitable for the charging field of electric tricycles and four-wheel vehicles.