DEMO MANUAL DC1362A-A/-B LT3651EUHE-4.2/-4.1 4A High Voltage Li-Ion Battery Charger DESCRIPTION Demonstration circuit 1362A-A/1362A-B is a 4A high voltage signal if the battery doesnt respond to preconditioning. The Li-Ion battery charger featuring the LT 3651EUHE-4.2/ LT3651EUHE is available in a 36-lead (5mm 6mm) QFN LT3651EUHE-4.1. The LT3651 is a complete, high power surface mount package with two exposed thermal pads. Li-Ion battery charger that can operate over a wide input Design files for this circuit board are available at voltage range. The charger is a constant-current, constant- POWER LOSS (W) DEMO MANUAL DC1362A-A/-B OPERATING PRINCIPLE Charge termination can occur when charge current de- battery temperature moves outside the safe charging range creases to one-tenth of the programmed maximum charge of 0C to 40C the charging cycle suspends and signals current (C/10 termination). Alternately, termination can a fault condition. be timer based through the use of an internal program- The LT3651 contains two digital open-collector outputs, mable charge cycle control timer. When using the timer which provide charger status and signal fault conditions. termination, charging continues beyond the C/10 level These binary coded pins signal battery charging, standby to top off a battery. Charging typically terminates three or shutdown modes, battery temperature faults and bad hours after initiation. When the timer-based scheme is battery faults. used, bad battery detection is also supported. A system A precision undervoltage lockout is possible by using a fault is triggered if a battery stays in precondition mode resistor divider on the shutdown pin (SHDN). The input for more than one-eighth of the total charge cycle time. supply current is 17A when the IC is in shutdown. Once charging is terminated and the LT3651 is not ac- tively charging, the IC automatically enters a low current 86 4.4 V = 3.9 standby mode in which supply bias currents are reduced BAT E FF to <85A. If the battery voltage drops below 2.5% from the 85 4.0 full charge float voltage, the LT3651 engages an automatic 84 3.6 charge cycle restart. The IC also automatically restarts a new charge cycle after a bad battery fault once the failed 83 3.2 battery is removed and replaced with another battery. 82 2.8 After charging is complete, the input bias current lines 81 2.4 P connected to the battery are reduced to minimize battery LOSS discharge. 80 2.0 5 10 15 20 25 30 32 The LT3651 contains provisions for a battery temperature DC1362ab F01 V (V) IN monitoring circuit. Battery temperature is monitored by Figure 1. Efficiency and Power Loss vs V IN using an NTC thermistor located with the battery. If the QUICK START PROCEDURE Demonstration circuit 1362A-A/1362A-B is easy to set 2. Turn on PS2 and slowly increase the voltage to 2.7V while up to evaluate the performance of the LT3651EUHE-4.2/ monitoring the current into the BAT pin. If the current LT3651EUHE-4.1. is less than 5mA, turn on PS1. Increase the voltage on PS1 to 4V while monitoring the input current. If the Using short twisted pair leads for any power connections, current is less than 5mA, increase PS1 to 12V. with all loads and power supplies off, refer to Figure 2 for the proper measurement and equipment setup. 3. Verify that the battery charging current, IBAT is between 400mA and 600mA. The CHRG LED and ACPR LED Follow the procedure below: should be on and the FAULT LED should be off. 1. Jumper and power supply setting: JP1 = RUN PS1 = OFF JP2 = C/10 PS2 = OFF dc1362aabfa 2 EFFICIENCY (%)