DEMO MANUAL DC1583A LTC3625/LTC3625-1: 1A High Efficiency 2-Cell Supercapacitor Charger with Automatic Cell Balancing DESCRIPTION Demonstration circuit 1583A is a 1A high efficiency 2- Cell supercapacitor charger with automatic cell balancing featuring the LTC3625/LTC3625-1. The LTC3625/LTC3625-1 are programmable supercapacitor chargers designed to charge two supercapacitors in series to a fixed voltage of 5.3V/4.8V (LTC3625) or 4.5V/4.0V (LTC3625-1) from a 2.7V to 5.5V input supply. Automatic cell balancing is achieved during the charging phase, preventing overvoltage damage to either supercapacitor while maximizing charge rate. High efficiency, high charging current, low quiescent current and low minimum external parts count make the LTC3625/LTC3625-1 ideally suited for small form factor backup or high peak power systems. Charging current/maximum input current level is programmed with an external resistor. When the input supply is removed and/or the EN pin is low, the LTC3625/LTC3625-1 automatically enters a low current state, drawing less than 1μA from the supercapacitors. The LTC3625/LTC3625-1 are offered in a 12-lead (3mm × 4mm × 0.75mm) DFN package. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY Typical Specifications (25°C) LTC3625 Input Voltage Range: VCC 2.7V to 5.5V Charge Current 1.0A VOUT 4.8V or 5.3V Dependant on JP1 Setting Typical Specifications (25°C) LTC3625-1 Input Voltage Range: VCC 2.7V to 5.5V Charge Current 1.0A VOUT 4.0V or 4.5V Dependant on JP1 Setting OPERATING PRINCIPLES The LTC3625/LTC3625-1 are dual cell supercapacitor chargers. Their unique topology charges two series connected capacitors to a fixed voltage with programmable charging current preventing overvoltage damage to either of the cells, even if they are severely mismatched. No balancing resistors are required. The LTC3625/LTC3625-1 include an internal buck converter between VIN and VMID to regulate the voltage on CBOT (the bottom capacitor) as well as an internal boost converter between VMID and VOUT to regulate the voltage on CTOP (the top capacitor). The output current of the buck converter is user-programmed via the PROG pin while the input current of the boost converter is set to 2A (typical). dc1583Af 1 DEMO MANUAL DC1583A OPERATING PRINCIPLES The LTC3625/LTC3625-1 contains various functions that are digitally controlled. The CTL pin is a control function that sets the device into a two inductor mode (low) or a single inductor mode (high). The CTL pin must be hard tied to either VIN or GND. A logic high on the VSEL pin sets VOUT to 5.3V/4.5V while a logic low sets VOUT to 4.8V/4.0V. The EN pin will enable the device with a logic high while a logic low disables the device and VOUT becomes high impedance. Charging Two 2:1 Mismatched Supercapacitors Buck Output Current vs RPROG 2500 IPROG CLAMPED 6 VIN = 3.6V VMID = 2V CTL = 0V IBUCK (mA) 1500 100 CTOP = 50F CBOT = 100F RPROG = 61.9k CTL = 0 VSEL = 0 5 VOLTAGE (V) 2000 Buck Efficiency vs IBUCK 4 95 90 VOUT 3 VMID 1000 2 500 1 EFFICIENCY (%) 3000 An internal undervoltage lockout (UVLO) circuit monitors VIN and keeps the LTC3625/LTC3625-1 disabled until VIN rises above 2.90V/2.63V if VSEL is high or 2.63V/2.63V if VSEL is low. Hysteresis on the UVLO turns off the LTC3625/ LTC3625-1 if VIN drops approximately 100mV below the UVLO rising threshold. When in UVLO, only current needed to detect a valid input will be drawn from VIN or VOUT. 85 80 75 70 65 60 55 0 0 0 50 100 150 200 250 300 350 400 450 500 RPROG (kΩ) 0 20 40 60 80 100 120 140 160 180 200 TIME (SECONDS) VIN = 3.6V VMID = 2V CTL = 0V 50 200 700 1700 1200 IBUCK (mA) 2200 QUICK START PROCEDURE Using short twisted pair leads for any power connections and with all loads and power supplies off, refer to Figure 1 for the proper measurement and equipment setup. Jumper and Load Settings to start: Connect Jumper from VOUT to VPULLUP JP1 (VSEL) = 5.3V/4.5V JP2 (ENABLE) = OFF LOAD1 = OFF 1. Set VIN to 3.3V and verify that the input current is less than 10mA. Verify that VOUT is less than 2.0V indicating that the supercapacitor is in a low charge state. 2. Set JP2 to the ON position. Verify that VOUT is less than 3.5V and that PGOOD is low. 3. Monitor PGOOD and VOUT. When PGOOD goes high, verify VOUT is ~5.0V/4.1V. 4. Verify VOUT when the input current drops to less than 10mA indicating a fully charged capacitor. Monitor PFO, verify PFO is high. Verify VOUT is ~5.3V/4.5V. 5. Turn on Load1 and set to 950mA. Monitor PGOOD and VOUT. When PGOOD goes low, verify VOUT is ~5.0V/4.1V. 6. Set JP2 to OFF, monitor PFO and PGOOD, verify both are low. Allow the supercapacitor to discharge to 1.5V, then turn off Load1. Note: Once JP2 is placed in the OFF position, VOUT will drop quickly. 7. Set JP1 to 4.8V/4.0V. Set JP2 to the ON position. Verify that VOUT is less than 3.0V and that PGOOD is low. dc1583Af 2 DEMO MANUAL DC1583A QUICK START PROCEDURE 8. Monitor PGOOD and VOUT. When PGOOD goes high, verify VOUT is ~4.5V/3.7V. 9. Verify VOUT when the input current drops to less than 10mA indicating a fully charged capacitor. Verify VOUT is ~4.8V/4.0V. 10. Turn on Load1 and set to 950mA. Monitor PGOOD and VOUT. When PGOOD goes low, verify VOUT is ~4.3V/3.5V. 11. Set JP2 to OFF and allow the supercapacitor to discharge to 1.0V, then turn off Load1. Figure 1. Proper Measurement Equipment Setup GND VIN Figure 2. Measuring Input or Output Ripple dc1583Af 3 DEMO MANUAL DC1583A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURERS/PART NUMBER Required Circuit Components 1 2 C1, C2 CAP, CHIP, X5R, 10μF, 20%, 6.3V, 0805 Murata, GRM21BR60J106E39L 2 2 C5, C6 CAP, CHIP, X5R, 22μF, 20%, 6.3V, 0805 Murata, GRM21BR60J226ME39L 3 2 C3, C4 CAP, CHIP, X7R, 0.1μF, 10%, 16V, 0402 Murata, GRM155R71C104KA88D 4 1 C9 Supercapacitor, 1.2F, 5.5V, 39mm × 17mm CAP-XX, HS230F 5 2 L1, L2 Inductor, 3.3μH, 3.0A, 20mΩ, 7mm × 7mm Coiltronics, DR73-3R3-R 6 1 R1 Res., CHIP, 1Ω, 1/16W, 1%, 0402 Vishay, CRCW04021R00FKED 7 1 R2 Res., CHIP, 100k, 1/16W, 1%, 0402 Vishay, CRCW0402100KFKED 8 1 R4 Res., CHIP, 71.5k, 1/16W, 1%, 0402 Vishay, CRCW040271K5FKED 9 2 R5, R6 Res., CHIP, 1M, 1/16W, 1%, 0402 Vishay, CRCW04021M00FKED 10 1 U1 1A High Efficiency 2-Cell Supercapacitor Charger with Automatic Cell Balancing LTC3625EDE Optional Demo Board Circuit Components 1 0 C7-1 - C8-1 (OPT) Supercapacitor, 10.0F, 2.7V, 10mm × 30mm Illinois CAP, 106DCN2R7Q 2 0 C7-2 - C8-2 (OPT) Supercapacitor, 25.0F, 2.7V, 16mm × 25mm Illinois CAP, 256DCN2R7Q 3 0 R3 (OPT) RES., CHIP, 1/16W, 1%, 0402 User Selectable 4 0 U1 1A High Efficiency 2-Cell Supercapacitor Charger with Automatic Cell Balancing LTC3625EDE-1 Hardware For Demo Board Only 1 5 E1 - E5 Turret, 0.09 DIA MILL-MAX, 2501-2 2 4 E6 - E9 Turret, 0.061 DIA MILL-MAX, 2308-2 3 2 JP1, JP2 Header, 3 PINS, 2mm Samtec, TMM-103-02-L-S 4 2 JP1, JP2 Shunt, 2mm Samtec, 2SN-BK-G dc1583Af 4 A GND E2 E1 VIN 2.7V - 5.5V R1 1 C2 10uF 6.3V 0805 4.8V / 4.0V 5.3V / 4.5V 1 3 VSEL 2 JP1 OFF ON ENABLE 1 3 2 JP2 * Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. U1 LTC3625EDE LTC3625EDE-1 -B 6 SW1 VOUT 13 GND PFO PGOOD VMID 4.5V - 4.0V 5.3V - 4.8V PROG R4 71.5k EN VSEL CTL PFI 8 9 10 1 R6 1M R5 1M 1 Unless noted: Resistors: Ohms, 0402, 1%, 1/16W Capacitors: uF, 0402, 6.3V 3.3uH L2 3.3uH L1 12 11 VOUT SW2 2 VIN -A 5 4 3 7 * U1 ASSY TYPE R3 OPT R2 100K 3 BAL V+ CUSTOMER NOTICE C6 22uF 6.3V 20% 0805 C5 22uF 6.3V 20% 0805 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. J. DREW SCALE = NONE NC PCB DES. APP ENG. APPROVALS C9 HS230F 1.2F 39mm x 17mm 5.5V LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. C4 0.1uF 16V C3 0.1uF 16V 2 1 C1 10uF 6.3V 0805 1 C8-1 10F OPT C7-1 10F OPT C8-2 25F OPT C7-2 25F OPT PFO PGOOD V PULL-UP GND GND VMID * VOUT DATE 06-15-10 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only E9 E8 E7 E6 E5 E4 E3 J. DREW APPROVED DATE: SIZE Monday, August 23, 2010 SHEET 1 OF 1 1A HIGH EFFICIENCY 2-CELL SUPERCAPACITOR CHARGER WITH AUTOMATIC CELL BALANCING IC NO. LTC3625EDE / LTC3625EDE-1 REV. N/A 2 DEMO CIRCUIT 1583A-A/B TECHNOLOGY + + DESCRIPTION 2 REVISION HISTORY PRODUCTION FAB REV TITLE: SCHEMATIC + + ECO A DEMO MANUAL DC1583A SCHEMATIC DIAGRAM dc1583Af 5 DEMO MANUAL DC1583A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1583Af 6 Linear Technology Corporation LT 1110 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2010