DEMO MANUAL DC1229B LT3650EDD-4.2/LT3650EDD-4.1 2A Monolithic Li-Ion Battery Chargers Description DC1229B is a 2A monolithic Li-Ion battery charger featur- a signal if the battery doesnt respond to preconditioning. ing the LT 3650EDD-4.2/LT3650EDD-4.1. The LT3650 is a The LT3650EDD is available in a 12-lead (3mm 3mm) complete mid-power Li-Ion battery charger that can operate DFN surface mount package with an exposed pad. over a wide input voltage range. The circuit provides CC/CV Design files for this circuit board are available at charging with a maximum charge current externally pro- DEMO MANUAL DC1229B o Ating p The LT3650 can use a charge-current based C/10 termina- voltage, the LT3650 engages an automatic charge cycle tion scheme, which ends a charge cycle when the battery restart. The IC also automatically restarts a new charge charge current falls to 1/10th the programmed maximum cycle after a bad battery fault once the failed battery is charge current. The LT3650 also contains an internal charge removed and replaced with another battery. cycle control timer, for timer-based termination. When using The LT3650 contains provisions for a battery temperature the internal timer, the IC combines C/10 detection with a monitoring circuit. This feature monitors battery tem- programmable time constraint, during which the charging perature during the charging cycle using a thermistor, cycle can continue beyond the C/10 level to top-off a and suspends charging and signals a fault condition if battery. The charge cycle terminates when a specific time the battery temperature moves outside a safe charging elapses, typically 3 hours. When the timer-based scheme range of 0C to 50C. is used, the IC also supports bad-battery detection, which The LT3650 contains two digital open-collector outputs, triggers a system fault if a battery stays in precondition which provide charger status and signal fault conditions. mode for more than 1/8th of the total charge cycle time. These binary-coded pins signal battery charging, standby Once charging is terminated and the LT3650 is not actively or shutdown modes, battery temperature faults, and bad charging, the IC automatically enters a low-current standby battery faults. mode where supply bias currents are reduced to < 100A. If the battery voltage drops 2.5% from the full-charge float q Uick st Art proce DU DC1229 is easy to set up to evaluate the performance of 4. Increase PS2 until V is 3.6V. Verify the input cur- BAT the LT3650EDD-4.2/LT3650EDD-4.1. rent, IIN, is between 700mA and 850mA, the battery current, I , is between 1.875A and 2.225A and that BAT Use a blocking diode on the input supply connection, and the CHRG LED is on. short twisted pair leads for the power connections. With all loads and power supplies off, refer to Figure 1 for the 5. Increase PS2 until V is 4.25V. Verify the battery BAT proper measurement and equipment setup. charging current, I , is less than 5mA and that the BAT CHRG LED is off. Follow the procedure below: 6. Decrease PS2 until V is 3.9V. Verify the battery BAT 1. Jumper and Power Supply Setting: current, I , is between 1.875A and 2.225A and that BAT JP1 = 1 PS1 = OFF the CHRG LED is on. JP2 = 1 PS2 = OFF 7. Decrease PS2 until V is 3.6V. Connect a 10k resistor BAT JP3 = C/10 from the RNG/SS pin to ground. Verify the charging 2. Turn on PS2 and slowly increase the voltage until V BAT current, I , is between 850mA and 1.0A. Verify the BAT is 2.7V while monitoring the current into the BAT pin. voltage, V , on the RNG/SS turret is between 450mV RNG If the current is less than 5mA, turn on PS1. Increase and 550mV and the voltage V on the NTC turret is NTC PS1 until V is 5V while monitoring the input current. IN between 1.8V and 1.9V. Remove the 10k resistor from If the current is less than 5mA, increase PS1 until V IN the RNG/SS pin to ground. is 12V. 8. Set JP1 to SHDN. Verify the charging current, I , is BAT 3. Verify that the battery charging current, I , is between BAT less than 5mA and that the FAULT LED and the CHRG 200mA and 300mA. The CHRG LED should be on and LED are off. the FAULT LED should be off. dc1229bf 2 re rinciples per