QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1088A-A & B DUAL INPUT STANDALONE LI-ION BATTERY CHARGERS LTC4096/LTC4096X DESCRIPTION Demonstration circuits DC1088A-A and -B are com- LTC4096X does not have trickle charge mode and plete standalone linear chargers that are capable of charges at full charge current when the battery is be- charging single cell Li-Ion or Li-Polymer batteries. low 2.9V. The LTC4096/LTC4096X will detect and automatically The charger may be disabled by setting the SUSP select the appropriate input a USB port or a 5V wall jumper, JP1, to the HI position. The CHRG LED indi- adapter input. The Input Power Present (PWR) pin cates when the charger is in charge mode. indicates when sufficient input power is available and Design files for this circuit board are available. Call can drive up to 120mA. The charge current is auto- the LTC factory. matically set to 500mA with the USB input and 1A with the wall adapter input. The charge cycle termi- LTC is a trademark of Linear Technology Corporation nates when the charge current decreases to 50mA. The LTC4096 operates in trickle charge mode (10% charge current) when the battery is below 2.9V. The Table 1. Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Adapter Input Voltage Range DCIN 4.25V 5.5V USB Input Voltage Range USBIN 4.25V 5.5V Output Float Voltage V Constant Voltage Mode 4.200V ( 0.6%) BAT Charge Current I Adapter Input Power Constant Current Mode 1A BAT Charge Current I Adapter Input Power Trickle Charge Mode (LTC4096 Only) 100mA BAT Charge Current I USB Input Power Constant Current Mode 500mA BAT Charge Current I USB Input Power Trickle Charge Mode (LTC4096 Only) 50mA BAT V Full Charge Current 1V IDC V Full Charge Current 1V IUSB QUICK START PROCEDURE The charger may be evaluated using an actual Li-Ion Refer to Figure 1 for proper measurement equipment battery, a bi-polar supply, or a battery simulator. setup and follow the procedure below. A battery simulator consists of an adjustable supply 1. Set the SUSP jumper, JP1, to the HI position. with a load resistor across the supply output. A 2.5 2. With the power supplies adjusted to 0V, connect 10W resistor value will provide a 1A load at 2.5V. This the USB Input, Adapter Input, and Battery Simula- will allow the power supply to sink and source current tor with series ammeters as illustrated in Figure 1. similar to a battery, but allows the battery voltage to An ammeter or a 100m current sense resistor be changed quickly or remain at the same value in- may be used to measure the battery charge cur- definitely. rent. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1088A-A & B DUAL INPUT STANDALONE LI-ION BATTERY CHARGERS 3. Connect voltmeters as shown in Figure 1 across 11. Slowly decrease the Battery Simulator voltage USB Input and Ground, across the Adapter Input, until the CHRG LED illuminates. This indicates that and Ground, and across the Battery Output and the BAT voltage reached the recharge voltage Ground. These voltmeters may also be used to threshold. measure the voltage on the IDC, IUSB, ITERM, and 12. Set the Adapter Input to 0V and slowly decrease PWR terminals. the USB Input until the CHRG LED turns off. The 4. Turn on the Battery Simulator supply to 2.5V and USB Input voltage is at the falling USB Under Volt- set the SUSP jumper to the LO position. age Lockout threshold and the PWR pin is equal to 0V. 5. Increase the Adapter Input until the CHRG LED illuminates and observe the Adapter Input voltage 13. Set the Battery Simulator voltage to 2.5V. Slowly and charge current. The Adapter Input voltage is at increase the USB Input voltage until the CHRG LED the rising DCIN Under Voltage Lockout threshold. illuminates. The USB input is at the rising USB Un- The PWR voltage is approximately equal to the der Voltage Lockout and the PWR voltage is ap- Adaptor Input voltage. The LTC4096 will be in proximately equal to the USB Input voltage. The trickle charge mode with a trickle charge current of LTC4096 is in trickle charge mode with a trickle 100mA. The LTC4096X will be in full charge mode charge current of 50mA. The LTC4096X is in full with a charge current of 1A. charge mode with a charge current of 500mA. 6. Increase the battery simulator supply to 3V and 14. Increase the USB Input voltage to 5V and slowly observe that the LTC4096 charge current will jump increase the Battery Simulator voltage to 3V. The to full charge with a charge current of 1A. The LTC4096 jumps to full charge mode with a 500mA LTC4096X charge current will remain at 1A. charge current. The LTC4096X charge current re- mains at 500mA. 7. Set the USB Input supply to 5V and slowly de- crease the Adapter Input until the charge current 15. Slowly increase the Battery Simulator until the suddenly drops to 500mA. The Adapter Input volt- charge current starts to decrease. The charger is age is at the falling DCIN Under Voltage Lockout now in constant voltage mode. threshold and the PWR voltage is approximately 16. Slowly increase the Battery Simulator voltage equal to the USB Input voltage. while observing the charge current. Observe that 8. Increase the Adapter Input voltage until the when the charge current decreases below the charge current jumps back to 1A. The part is now 50mA termination current, the charge cycle termi- utilizing the Adapter Input power and the PWR nates. voltage is approximately equal to the Adapter Input 17. Slowly decrease the Battery Simulator voltage voltage. until the CHRG LED illuminates. This indicates that 9. Set the Adapter Input voltage to 5V and slowly the BAT voltage reached the recharge voltage increase the Battery Simulator voltage until the threshold. charge current starts to decrease. The charger is 18. Set the SUSP jumper the HI position. This dis- now in constant voltage mode. ables the charger and puts the part into shutdown. 10. Continue slowly increasing the Battery simulator 19. Set the Adapter Input supply to 5V and observe voltage while observing the charge current. Ob- the Adapter Input current and the current to the serve when the charge current decreases below the Battery Simulator. The part remains in shutdown 50mA termination current, the charge cycle termi- with the SUSP jumper in the HI position. nates. 2