DEMO CIRCUIT DC1132A Quick Start Guide LTC3566EUF: High Efficiency USB Power Manager Plus 1A Buck-Boost Converter DESCRIPTION Demonstration Circuit 1132A is a high efficiency USB Power/Li-Ion battery manager plus a 1A Buck-Boost regulator. The LTC3566EUF is available in a 24-pin (4mm x 4mm) QFN surface mount package. L, LTC, Burst Mode, Bat-Track are registered trademarks of Linear Technology Corporation. PowerPath and SwitcherCAD are trademarks of Linear Technology Corporation. Other product names may be trademarks of the companies that manufacture the products. PERFORMANCE SUMMARY Specifications are at TA = 25C SYMBOL VBUS VOUT VBAT IBAT VOUT1 IOUT1 PARAMETER Bus Input Voltage Range Output Voltage Range Output Float Voltage Output Charge Current Buck-Boost Output Voltage Buck-Boost Output Current CONDITIONS Range is mode and load dependant Constant voltage mode Constant current mode MIN 4.35 3.5 TYP 4.2 0.5 3.25 MAX 5.5 4.6 1 3.30 1 OPERATING PRINCIPLES The LTC3566EUF is a full featured USB Power Manager and Li-Ion battery charger with a 1A Buck-Boost DC/DC regulator. The Bat-TrackTM battery charger pre-regulator ensures the charger operates at the highest possible efficiency. The LTC3566EUF is composed of 5 functional blocks, all working together: USB Power Manager, Pre-regulator, Battery Charger, Ideal Diode, and 1A Buck-Boost DC/DC regulator. USB Power Manager The USB Power Manager is used to manage the load that the LTC3566EUF system presents to the USB interface. The load current can be programmed by changing the CLPROG resistor (R2), and by setting the operating mode to 1X, 5X or 10X with the ILIM1, ILIM0 jumpers. Buck-Boost Regulator Efficiency UNITS V V V A V A QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF Pre-Regulator The pre-regulator is a high efficiency buck regulator that produces a voltage at VOUT equal to the battery voltage plus 0.3V. By reducing the voltage across the charger to 0.3V the dissipation in the charger is greatly reduced, as compared with a linear charger. Battery Charger The battery charger operates in constant current mode, until the battery voltage rises to approximately the FLOAT voltage, of 4.2V, and then the charger switches to constant voltage mode. The charge current is programmed by the PROG resistor (R3), and has been set to 500mA, on DC1132A, with a 2.00k resistor. The battery charger implements trickle charging, for initial battery voltages less than 2.85V. It also implements a charge termination timeout of 4 hours, and a bad cell charging timeout of 30 minutes. An NTC input is used to determine if the battery temperature is suitable for charging, too hot or too cold. The Buck-Boost is implemented with a full H-bridge switch, and proprietary control algorithm. VOUT1 EN1 Figure 1. VOUT1 startup IOUT1 = 100mA The status of the charger, as well as any faults, are signaled with the CHRG pin. Ideal Diode The Ideal Diode block is composed of an internal Ideal Diode implemented with an on die MOSFET, as well as a MOSFET gate driver that allows the use of a parallel external MOSFET. When the voltage on VOUT drops more than 15mV below the voltage at BAT, the Ideal Diode becomes active. This will happen when VBUS is not present, or the load on VOUT exceeds the power available from VBUS. Figure 2. SWAB1 switching IOUT1 = 100mA 1A Buck-Boost DC/DC regulator The Buck-Boost DC/DC regulator provides a regulated output that can be above and below the input voltage. The battery voltage will vary from VFLOAT (4.2V) to as low as 2.5V. The Buck-Boost regulator can supply a regulated 3.3V output over this entire battery voltage range. Figure 3. SWCD1 waveform 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF APPLICATIONS INFORMATION The parasitic inductance in some USB cables may cause the VUSB voltage to overshoot at plug in. If this is the case it is recommended that the network of C1,R1 and C2 be added to the board to damp out this overshoot. While, at first glance, it may appear that C1 + C2 exceeds the USB specification for capacitive load on VUSB, in fact this is not the case. For most MLCC capacitors, with X7R/X5R dielectric the capacitance will be below 4.7F, for DC biases of 5V. The battery charger must see low impedance to ground, which is the case when a battery is attached. In the event that a battery emulator is being used, or the impedance to ground is above 0.5, the circuit of C5 and R8-10 is recommended. The Buck-Boost regulator should be compensated with a Type III compensator, as shown on the schematic. The Buck, Buck-Boost and pure Boost regions of operation have different poles/zeroes and PWM gains. In particular, the BuckBoost and pure Boost regions have a RHP zero, that must be accommodated. It is recommended that the stabilization be verified in all three regions of operation, with minimum and maximum load. 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF QUICK START PROCEDURE Using short twisted pair leads for any power connections and with all loads and power supplies off, refer to Figures 4 and 5 for the proper measurement and equipment setup. Follow the procedure below: 1. Set PS1 to 5V, and PS2 to 3.6V. 2. Observe IVBUS (AM1). The USB input current limit is programmed for 1X (100mA), but the battery charge current is programmed to 500mA. So the USB input current limit is activated, and the charger cannot get enough current to charge at 500mA. Consequently, VCLPROG is at ~1.15V, but VPROG cannot rise to 1V. 3. Set ILIM1 (JP2) to "HI" and ILIM0 (JP3) to "HI". Observe IVBUS (AM1). The USB input current limit is now 5X (500mA), and the charger can get enough current to charge the battery at 500mA. Consequently, VCLPROG is nearly 1.15V, and VPROG is at 1V. 4. Set ILIM1 (JP2) to "LO". Observe IVBUS (AM1), VCLPROG (VM6) and VPROG (VM5). The USB input current limit is now 10X (1A), and the charger can get enough current to charge the battery at 500mA. Consequently, VCLPROG is at 0.6V (0.5 * 1.15V), and VPROG is at 1V. 5. Set PS1 to 0V, and LOAD1 to 1A. Observe VOUT (VM2) and V(BAT,OUT). Verify that 3.55V < VOUT < 3.60V, and (VBAT - VOUT) < 0.05V. The USB input voltage is off causing VOUT to fall. When VOUT falls to 15mV below VBAT, the LTC3566 activates the ideal diode and supplies current to VOUT from the BAT pin. 4 6. Set LOAD1 to 400mA and PS1 to 5V. Observe VOUT (VM2), VCLPROG (VM6) and VPROG (VM5). The USB input current limit is 10X (1A), and the charger can get enough current to charge the battery at 500mA. In addition, VOUT is being loaded at 400mA, producing an aggregate load at VBUS of nearly 860mA. Consequently, VCLPROG is nearly 1.15V, and VPROG is at 1V. 7. Observe VOUT (VM2) and VOUT1 (VM4). The Buck-Boost regulator has been enabled at no load. The nominal output voltage on the Buck-Boost regulator is 3.3V. 8. Leave LOAD1 at 400mA, and set LOAD2 to 400mA. Observe VOUT (VM2), VOUT1 (VM4) and VCLPROG (VM6). The USB input current limit is 10X (1A), and the charger can get enough current to charge the battery at 500mA. In addition, VOUT1 is being loaded at 400mA, producing an aggregate load at VBUS of nearly 860mA. Consequently, VCLPROG is nearly 1.15V, and VPROG is at 1V. 9. Set CHRGEN (JP4) to "HI". Set LOAD2 to 1A. Observe VOUT (VM2), VOUT1 (VM4), and VCLPROG (VM6). The USB input current limit is 10X (1A), and the charger is off. In addition, VOUT1 is being loaded at 1A, producing an aggregate load at VBUS of nearly 860mA. Consequently, VCLPROG is nearly 1.15V, and VPROG is at 1V. 10. Set LOAD2 to 0A, and CHRGEN (JP4) to "LO". Set NTC (JP6) to "EXT". CHRG LED should flash. The charger is now enabled, but the voltage is indicating that the battery temperature is very cold. 11. Set NTC (JP6) to "INT" and EN1 (JP1) to "ON". QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF AM2 - + - + VM2 - + LOAD1 0V-5V 2A - + AM1 - + VM3 + PS1 + 0V-6V supply 2A - AM3 + 3.6 - VM1 - PS2 0V-5V supply 2A - VM4 + - VM6 - VM5 - + Figure 4. Proper Measurement Equipment Setup for DC1132A GND VIN Figure 5. Measuring Input or Output Ripple - + + 5 + AM4 + - LOAD2 0V-5V 2A GND Figure 6. DC1132A Schematic E6 GND E5 E4 E3 E2 PROG NTC ID D+ GND TP2 TP3 3 4 5 TP1 2 1 D+ ID D- R1 1.0 5% SUSPEND (500uA) 1 0 1 0 1 1 R5 100K 1A (10X) 0 R6 0 PWM INT JP6 NTC EXT R4 100K VBUS 100mA (1X) ILIM0 0 CURRENT LIMIT LO JP5 MODE ILIM1 500mA (5X) LO JP3 ILIM0 LO JP2 ILIM1 OFF JP1 EN1 JP4 CHRGEN C1 10uF 16V 0805 INPUT CURRENT LIMIT SETTINGS USBMINI-B CLPROG USB D- VBUS J1 VBUS R7 0 BURST HI HI HI ON VOUT R2 3.01k C4 0.1uF 16V R3 2K C3 22uF 6.3V 0805 C2 10uF 16V 0805 3 15 2 8 23 13 14 24 9 NTC 21 GND 25 6 VBUS GND PROG CLPROG MODE CHRGEN ILIM0 ILIM1 EN1 VIN1 LTC3566EUF U1 VBUS 12 GND 19 5 4 7 11 10 18 16 20 22 1 L2 3.3uH C6 330pF 5% R11 15k C7 10pF +/-0.5pF L1 2.2uH LPS4018-222MLC LPS4018-332MLC Unless noted: Resistors: Ohms, 0402, 1%, 1/16W Capacitors: uF, 0402, 10%, 50V 17 GND BAT VC1 FB1 SWAB1 SWCD1 VOUT1 GATE CHRG VOUT SW LDO3V3 C9 22uF 6.3V 0805 20% TP5 R17 0 OPT R13 121k C8 33pF 5% R12 105k R14 324k TP4 INJ R15 20 5% C10 22uF 6.3V 0805 20% C11 1uF 10V R8 1.0 5% 1 2 3 R9 1.0 5% C5 100 6.3V 1206 20% R10 1.0 5% Q1 Si2333DS R16 1k 5% 0603 D1 GREEN CHGR VOUT 1 6 2 E1 VBUS 4.35V-5.5V CHRG GND 1A NTC-EXT GND BAT J2 E7 GND DF3-3P-2DSA OPT 3 2 1 E8 BAT VFLOAT=4.2V 500mA E9 E10 VOUT1 3.3V E11 E12 GND VOUT 3.5V-4.6V 1.25A E13 E15 LDO3V3 3.3V 25mA E14 GND QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC1132A HIGH EFFICIENCY USB POWER MANAGER PLUS 1A BUCK-BOOST CONVERTER LTC3566EUF Figure 7. DC1132A BOM 7