QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1189A HIGH EFFICIENCY BATTERY CHARGER/USB POWER MANAGER WITH REGULATED OUTPUT VOLTAGE LTC4088-1 DESCRIPTION Demonstration Circuit 1189 is a high efficiency USB or if the USB or wall supply is removed. The external P- TM power manager with PowerPath control and Li- channel MOSFET supplements the internal ideal diode ion/Polymer battery charger featuring the LTC 4088-1. by reducing R and increasing efficiency. ON The LTC4088-1 includes a synchronous switching input A CHRG LED indicates four possible states of the bat- regulator, a full-featured battery charger and an ideal tery charger. Charging is indicated when the LED is diode. Designed specifically for USB applications, the steady-ON. Not charging is indicated by a steady-OFF. LTC4088-1s switching regulator automatically limits its A NTC fault is indicated by a slow blinking rate input current to either 100mA, 500mA or 1A for wall- (1.5Hz) and a bad battery is indicated by a fast blink- powered applications via logic control. ing rate (6.1Hz). The switching input stage provides power to VOUT where power sharing between the application circuit and The LTC4088-1 is available in the low profile 14-Lead the battery charger is managed. Charge current is auto- 4mm 3mm 0.75mm DFN surface mount package. matically reduced to maintain a regulated 3.6V VOUT during low battery conditions. As the battery is charged, VOUT tracks VBAT for high efficiency charging. This fea- Design files for this circuit board are available. Call ture allows the LTC4088-1 to provide more power to the the LTC factory. application and eases thermal issues in constrained applications. , LTC and LT are registered trademarks of Linear Technology Corporation. PowerPath is a trademark of Liner Technology Corporation. An ideal diode ensures that system power is available from the battery when the input current limit is reached Table 1. Typical Specifications (25C) Input Voltage Range, VBUS 4.35V to 5.5V VOUT 3.5V to 4.7V (Mode and load dependent) 3.3V 3.3V (Load and VOUT dependent) Output Float Voltage V (constant voltage mode) 4.2V BAT Output Charge Current I (constant current mode) 0.5A (R equals 2.00KW) BAT PROG QUICK START PROCEDURE Refer to Table 1 for a listing of the inputs and outputs Refer to Figure 1 for the proper measurement and of the 1189 Demo Circuit. Demo Circuit 1189 is best equipment setup and follow the procedure below. evaluated using a Li-Ion/Polymer battery. When using 1. If using an external supply, connect a 0 to 6V, a battery simulator for evaluation, oscillations must be 1.5A supply with voltage adjusted to 0V be- verified with a real battery at the same conditions tween the VBUS and GND terminals. Connect a because it is difficult to match the impedance of a Voltmeter across the VBUS and GND terminals. real battery, which is required for battery charger If using the USB input option, have cable ready stability. to plug in when all loads and jumpers are set. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1189A HIGH EFFICIENCY BATTERY CHARGER/USB POWER MANAGER WITH REGULATED OUTPUT VOLTAGE LTC4088-1 Do not use the USB input and an external sup- ply at the same time. 2. Set JP1, NTC jumper to INT to use the demo board resistor. To use an external 100kOhm NTC resistor, connect the NTC resistor between J2-3 and the GND terminal. Then set the NTC jumper to EXT. 3. Use Table 2 to set JP2, JP3, and JP4 (D0, D1, and D2 respectively) to select the desired input See the datasheet for the proper values of I and BUSQ current limit and charger status. h in the 1X, 5X and 10X modes. CLPROG TABLE 2. Controlled Input Current Limit 6. If using the USB input, plug in the USB cable D0 D1 D2 CHARGER I LIM and observe the battery charge current and 0 0 0 OFF 100mA(1x) VOUT. If using an external power supply, slowly 0 0 1 ON 100mA(1x) increase the supply and observe that the 0 1 0 OFF 500mA(5x) LTC4088-1 starts to use the VBUS input power 0 1 1 ON 500mA(5x) as VBUS reaches 4.35V. 1 0 0 OFF 1A(10x) 7. Discharge the battery to 2.5 volts. If Charger 1 0 1 ON 1A(10x) mode is on, observe it is charging in trickle 1 0 1 OFF 2.5mA(Susp High) charge mode and the charge current is 50mA. 1 1 1 OFF 500uA(Susp Low) As the battery voltage increases above 2.85V observe that the charger goes into full constant 4. Connect a 0 to 2A adjustable load in series with current mode. Observe that VOUT stays above an ammeter between the VOUT terminal and the 3.6V when the input current limit is not ex- GND terminal. Connect a Voltmeter between the ceeded. Remove the NTC jumper on JP2. Ob- VOUT and GND terminals. serve the CHRG LED slow blinking rate. Also observe the 35KHz pulse with varying duty cy- 5. Connect a partially charged (~3.6V) Lithium ion battery with the positive lead to the BAT termi- cle between 4.7% and 95.3% on the CHRG nal and the negative lead to a GND terminal. terminal with an oscilloscope. Reinstall the NTC Connect the positive lead of a Voltmeter to the jumper. BAT terminal and the negative lead to the GND 8. Increase the VOUT load and observe when the terminal. Connect the positive terminal of a input current starts to limit (V =1.188 V). CLPROG Voltmeter to PROG and the negative terminal to When input current limit is reached, VOUT GND to measure the current flowing into the drops from 300 mV above the BAT voltage to battery. The voltage on PROG will read 1 Volt 15mV below the BAT voltage and the additional when the maximum charge current is reached. load transitions to the battery through the ideal The voltage on CLPROG will read 1.188 Volts diode. Due to the high efficiency of the switch- when the input current limit is reached. Ob- ing regulator, the charge and load current may serve VOUT. be significantly above the input current depend- ing on the voltage on the BAT pin. 2