CONSONANCE Figure 5 Adjusting Regulation Voltage in Constant Voltage Mode In Figure 5, the regulation voltage in constant voltage mode will be given by the following equation: VREG ＝ 4.2＋3.707×10-6×Rx Where, VREG is in volt Rx is in ohm Setting Charge Current The formula for the battery charge current in constant current mode is: ICH = 1188V / RISET Where: ICH is the charge current in ampere RISET is the total resistance from the ISET pin to ground in ohm For example, if 1000mA charge current is required, calculate: RISET = 1188V/1A = 1.18kΩ For best stability over temperature and time, 1% metal film resistors are recommended. If the charger is in constant-temperature or constant voltage mode, the charge current can be monitored by measuring the ISET pin voltage, and the charge current is calculated as the following equation: ICH = (VISET / RISET) × 986 Combine Two Power Inputs Although the CN3165 allows charging from a solar power supply, a wall adapter or a USB port can also be used to charge Li-Ion/Li-polymer batteries. Figure 6 shows an example of how to combine 2 power inputs. A P-channel MOSFET, M1, is used to prevent back conducting into the 2nd power supply when the 1st power supply is present and Schottky diode, D1, is used to prevent 2nd power supply loss through the 1kΩ pull-down resistor. www.consonance-elec.com 8 REV 1.0
