QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 654 LI-ION BATTERY CHARGER IN SOT23-6 WITH EXTERNAL TERMINATION LTC4057ES5-4.2 DESCRIPTION Demonstration circuit 654 is a sim- sibility of the system. The ple single Li-Ion battery charger LTC4057 does however indicate bat- featuring the LTC4057ES5-4.2. tery-charging current on the PROG Maximum charge current is 600mA. pin, which simplifies the task for The LTC4057 provides the constant the external terminator. current, constant voltage source Design files for this circuit board required to charge Li-Ion batter- are available. Call the LTC fac- ies. The LTC4057 does not termi- tory. nate charging, that is the respon- Table 1. Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Minimum Input Voltage 4.25V Maximum Input Voltage 6.5V Float Voltage V V = 5V 4.2V 1% IN Maximum Output Current V = 5V, 2.9V <V <4.1V 600mA 7% IN BAT Trickle Charge Current V = 5V, V <2.8V 25-85mA IN BAT Prog/Monitor Voltage V = 5V, 1.6mV/mA IN OPERATING PRINCIPLES Demonstration circuit 654 imple- thermal loop will reduce charge ments a constant current, constant current from the programmed value. voltage charge algorithm suitable Otherwise, programmed charge cur- for Li-Ion batteries. Deeply dis- rent will flow into the battery un- charged batteries are trickle til the battery voltage begins to charged at 10% of full charge rate. approach the final float value. As Once the battery voltage reaches the battery reaches full charge the 2.9V normal full rate charging will LTC4057 enters constant voltage begin. Full charge current is set mode, and the charge current begins by the value of the resistor on the to taper. The LTC4057 does not PROG pin of the LTC4057. In the terminate the charging process and event that full charge current will remain in the float condition would result in excessive tempera- indefinitely. Charge termination ture rise, due to some combination is left to the user. Grounding the of input voltage, battery voltage, SHDN pin will terminate the charg- ambient temperature or PCB thermal ing cycle. Charge current informa- characteristics, the LTC4057s tion is provided to the user at the 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 654 LI-ION BATTERY CHARGER IN SOT23-6 WITH EXTERNAL TERMINATION PROG pin. 100% charge current is 0V at 0% charge current. 1.00 volt, decreasing linearly to QUICK START PROCEDURE Demonstration circuit 654 is easy 4. Vary the voltage on the simulated to set up to evaluate the perform- battery and note the charge cur- ance of the LTC4057. Refer to rent, and the voltage on the Prog Figure 1 for proper measurement pin. equipment setup and follow the pro- 5. Move the Charger enable jumper cedure below: (JP1) to OFF to simulate an ex- 1. With power off, connect the input ternal termination signal. power supply, output load and me- ters as shown in Figure 1. 2. Turn on the power at the input. NOTE: Make sure that the input voltage does not exceed 6.5V. 3. Set the Charger enable jumper (JP1) to ON 2