DEMO MANUAL DC1007C LTC4088 High Efficiency Battery Charger/Power Manager DESCRIPTION Demonstration Circuit 1007 is a high efficiency USB power battery and eases thermal issues in space constrained manager with PowerPath control and Li-Ion/Polymer applications. battery charger featuring the LTC 4088. It includes a syn- An ideal diode ensures that the system power is available chronous switching input regulator, a full featured battery from the battery when the input current limit is reached or charger and an ideal diode. Designed specifically for USB if the USB or wall supply is removed. The optional external applications, the LTC4088s switching regulator automati- P-channel MOSFET supplements the internal ideal diode cally limits its input current to either 100mA, 500mA or by reducing R and increasing efficiency. ON 1A for wall-powered applications via logic control. There A CHRG LED indicates four possible states of the battery are also 2.5mA and 500A suspend modes to prevent the charger. Charging is indicated when the LED is steady-ON. battery from running down when the product is connected Not charging is indicated by a steady-OFF. A NTC fault is to a suspended USB bus. indicated by a slow blinking rate (1.5Hz) and a bad battery The switching input stage provides power to VOUT where is indicated by a fast blinking rate (6.1Hz). power sharing between the application circuit and the The LTC4088 is available in the low profile 14-Lead battery charger is managed. Unlike linear PowerPath 4mm 3mm 0.75mm DFN surface mount package. controllers, the LTC4088s switching input stage can use nearly all of the 0.5W or 2.5W available from the USB port Design files for this circuit board are available at with minimal power dissipation. This feature allows the DEMO MANUAL DC1007C QUICK START PROCEDURE Demonstration circuit 1007 is best evaluated using a Li- 4. Connect a 0mA to 25mA adjustable load in series Ion/Polymer battery. When using a battery simulator for with an ammeter between the 3.3V and GND termi- evaluation, oscillations must be verified with a real battery nals. Connect a voltmeter between the 3.3V and GND at the same conditions because it is difficult to match the terminals. impedance of a real battery, which is required for battery 5. Connect a 0A to 2A adjustable load in series with an charger stability. ammeter between the VOUT terminal and the GND Refer to Figure 1 for the proper measurement and equip- terminal. Connect a voltmeter between the VOUT and ment setup and follow the procedure below. GND terminals. 1. If using an external supply, connect a 0V to 6V, 1.5A 6. Connect a partially charged (~3.6V) lithium-ion bat- supply with voltage adjusted to 0V between the VBUS tery with the positive lead to the BAT terminal and the and GND terminals. Connect a voltmeter across the negative lead to a GND terminal. Connect the positive VBUS and GND terminals. If using the USB input op- lead of a voltmeter to the BAT terminal and the nega- tion, have cable ready to plug in when all loads and tive lead to the GND terminal. Connect the positive jumpers are set. Do not use the USB input and an terminal of a voltmeter to PROG and the negative external supply at the same time. terminal to GND to measure the current flowing into the battery. The voltage on PROG will read 1V when 2. Set JP1, NTC jumper to INT to use the demo board the maximum charge current is reached. The voltage resistor. To use an external NTC resistor, connect an on CLPROG will read 1.188V when the input current NTC resistor between J2 - J3 and the GND terminal. is reached. Observe VOUT and the 3.3V output. Then set the NTC jumper to EXT. V PROG 3. Use Table 1 to set JP2, JP3, and JP4 (D0, D1, and D2 I = 1031 BAT R respectively) to select the desired input current limit PROG and charger status. V CLPROG I =I + h +1 ( ) VBUS BUSQ CLPROG Table 1. Controlled Input Current Limit R CLPROG D0 D1 D2 CHARGER I LIM 0 0 0 ON 100mA (1) See the data sheet for the proper values of I and BUSQ 0 0 1 OFF 100mA (1) h in the 1, 5 and 10 modes. CLPROG 0 1 0 ON 500mA (5) 7. If using the USB input, plug in the USB cable and ob- 0 1 1 OFF 500mA (5) serve the charge current, VOUT, and the 3.3V output. 1 0 0 ON 1A (10) If using an external power supply, slowly increase the 1 0 1 OFF 1A (10) supply and observe that the LTC4088 starts to use 1 1 0 OFF 500A (SUSP) the VBUS input power as the VBUS reaches 4.35V. 1 1 1 OFF 2.5mA (SUSP) dc1007cf 2