This paper introduces a high current (up to 1a) lithium battery charging circuit which can be set with charging current. It is simple and easy to make, and has charging indicator light and full indicator light. After full charge, the whole circuit can automatically be in micro power consumption and power saving mode. The input voltage range of the charging circuit is 4.5-6v, and the lithium battery can be charged by the mobile phone charger.
The circuit is shown in the figure above. Tp4056 is a special IC for single lithium battery charging. Its working voltage range is 4-8v, and the typical value is 5V (in fact, the voltage should not reach the limit value of 8V to avoid damaging the IC). The charging current can be set by the external resistance, and the charging termination voltage is 4.2V. The IC also has a charging control terminal. When the control terminal is low power level, the circuit stops charging and is in the state of micro power consumption and power saving. In addition, the charging output stage of tp4056 is p-channel MOS FET, so it is not necessary to connect anti backflow diode between the ⑤ pin of charging output terminal and lithium battery in use. When the input charging voltage is removed, tp4056 will automatically enter the micro power consumption state, and the current of lithium battery flowing into tp4056 is not more than 2 μ a.