Shandong GD36 charger circuit

Shandong GD36 charger circuit

Shown is the Shandong GD36 charger circuit. This charger is a half-bridge charger, with main performance indicators: input voltage, 170~
260 V; output voltage +44V (adjustable); maximum charging current 18 A; float charging current 200-100 mA.
    The charger circuit is mainly composed of mains rectification and filtering, self-excited plus separately excited half-bridge conversion, PWM control, voltage control, current control , output rectification and filtering, etc.     The whole e filter circuit is the mains power 220v50 FIz which is rectified by bridge type diode DI-D4 and filtered by capacitor C5--C7 to obtain a DC voltage of about 310 V, which is used as the power supply of the switching converter.     The self-excited plus separately excited half-bridge conversion circuit is mainly composed of Ql, Q2, B2, B3 and other devices.     PWM control is composed of TL494 as the core. C12, R19 and the internal circuit form or oscillate. When the parameters of these two resistor-capacitor components are the values ​​shown in the icon, the oscillation frequency is about 50 kHz. @pin is connected to +5 V,. The impulse output mode is set to push-pull output, and the push-pull width modulated pulses output by pins ⑧ and @ are amplified by the driver channel and then sent to the half-bridge output stage.     Voltage and current control: R26 and R27 are voltage negative feedback sampling resistors. R26 and R27 divide the voltage to sample the output voltage and add it to the ① pin of TIA94 for voltage control. R3 is a current sampling resistor, and the sampling voltage is added to the @ pin of TL494 through R13 for current control. The essence of current control is also to control the output voltage .