DC654A

DC654A demonstration circuit is a simple single Li-Ion battery charger featuring the LTC4057ES5-4.2. Maximum charge current is 600mA. The LTC4057 provides the constant current, constant voltage source required to charge Li-Ion batteries. The LTC4057 does not terminate charging, that is the responsibility of the system. The LTC4057 does however indicate battery-charging current on the PROG pin, which simplifies the task for the external terminator. Demonstration circuit 654 implements a constant current, constant voltage charge algorithm suitable for Li-Ion batteries. Deeply discharged batteries are trickle charged at 10% of full charge rate. Once the battery voltage reaches 2.9V normal full rate charging will begin. Full charge current is set by the value of the resistor on the PROG pin of the LTC4057.

• 4.25V minimum input voltage
• 6.5V maximum input voltage
• 4.2V ±1% float voltage at VIN = 5V
• 600mA±7% maximum output current at VIN = 5V, 2.9V <VBAT <4.1V
• 25-85mA trickle charge current at VIN = 5V, VBAT <2.8V
• 1.6mV/mA prog/monitor voltage at VIN = 5V