- Jan 09, 2018 -
The principle of fast charger circuit
AC220V city electricity through the transformer T1 depressurization, after the D1-D4 full wave rectification, supply charging circuit work. When the output terminal is connected to the set of charged bottles according to the correct polarity, if the half wave peak value of the rectifier output pulsation voltage exceeds the output voltage of the battery, then the thyristor SCR is triggered by the collector current of Q, and the current is charged by the thyristor to the battery. When the pulsating voltage is close to the voltage of the battery, the thyristor is turned off and the charge is stopped. Adjusting the R4, it can adjust the conduction voltage of the transistor Q. In general, the R4 can be adjusted from large to small to the Q conduction can trigger the thyristor (conduction). The light emitting tube D5 is used as a power indicator, and D6 is used as a charging indicator.
The mobile phone to realize fast charge function needs to meet the three elements, the three are indispensable. Charger, battery, charge IC. The charger needs to satisfy enough output current and output voltage, because the charger has large parasitic resistance. If we want to achieve a large charging current, the output voltage of the charger needs to be higher.