TP4055 Lithium Battery Charger IC | 500mA

Open Drain Charge Status Output When the battery is being charged, the CHRG pin is pulled low by the internal switch to indicate that charging is in progress; otherwise, the CHRG pin is in a high-impedance state.

Battery Connection Pin This pin provides the charging current to the battery and adjusts the final float voltage to 4.2V. An accurate internal resistor divider for this pin sets the float voltage, which in the shutdown mode, the internal resistor divider is disconnected

Positive Input Supply Voltage This pin supplies power to the internal circuit. Vcc varies from 4V to 9V and should be bypassed by at least one 10μF capacitor. When Vcc drops to within 30mV of the BAT pin voltage, TP4055 enters low power sleep mode, dropping BAT pin’s current to less than 1uA.

Charge current setting, charge current monitoring and shutdown pin A precision of 1% of the resistance RPROG between the pin and ground to set the charge current. When in constant charge current mode, the voltage of the pin is maintained at 1V. The PROG pin can also be used to turn off the charger. Setting the resistor to ground, a 2.5uA current internally pulls the PROG pin high. When the pin voltage reaches the shutdown threshold voltage 2.7V, the charger enters shutdown mode, charging is stopped and the input supply current to 40μA.Re-connecting RPROG to ground will cause the charger to return to normal operation.