CAT3224 4 Amp Supercapacitor Flash LED Driver Description http://onsemi.com TQFN−16 HV3 SUFFIX CASE 510AD RF VIN CP RT LEDB FLAG LEDA CAP FLASH CAP TORCH RC CHRG 2 Channels at 2 A Each in Flash Mode 2 Channels at 200 mA Each in Torch Mode Adjustable Charge Current Limit up to 1000 mA Flash/Torch Current Separate Adjustment Dual−mode 1x/2x Charge Pump Dual Cell Supercapacitor Balancing Flash Safety Timer and Ready Flag Supercapacitor Continuous Charging Shutdown CAP Leakage 3 mA “Zero” Current Shutdown Mode 80 mA Standby Current (IVIN) Over−voltage, Over−current Limiting Thermal Shutdown Protection Small 3 mm x 3 mm, 16−pad TQFN Package This Device is Pb−Free, Halogen Free/BFR Free and RoHS Compliant 1 BAL Features • • • • • • • • • • • • • • • CN PIN CONNECTIONS GND The CAT3224 is a very high−current integrated flash LED driver which also supports the charging function for a dual−cell supercapacitor applications. Ideal for Li−ion battery−powered systems, it delivers up to 4 A LED flash pulses, far beyond the peak current capability of the battery. Dual−mode 1x/2x charge pump charges the stacked supercapacitor to a nominal voltage of 5.4 V, while an active balance control circuit ensures that both capacitor cell voltages remain matched. The nominal charging current to be drawn from the battery is set by an external resistor tied to the RC pin. The driver also features two matched current sources. External resistors provide the adjustment for the maximum flash mode current (up to 4 A) and the torch mode current (up to 400 mA). A built−in safety timer automatically terminates the flash pulse beyond a maximum duration of 300 ms. In addition to thermal shutdown and overvoltage protection, the device is fully protected against external resistor programming faults and fully supports reverse output voltage for all conditions. The device is packaged in the tiny 16−pad TQFN 3 mm x 3 mm package with a max height of 0.8 mm. (Top View) MARKING DIAGRAM JAAT JAAT = Specific Device Code ORDERING INFORMATION Device Package CAT3224HV3−GT2 TQFN−16 (Pb−Free) Shipping 2,000/ Tape & Reel Note: NiPdAu Plated Finish (RoHS−compliant) Applications • High Power LED Flash • Systems with High Peak Loads © Semiconductor Components Industries, LLC, 2009 December, 2009 − Rev. 0 1 Publication Order Number: CAT3224/D CAT3224 1 mF CP VIN (2.5 V to 5.5 V) 1 mF CAP CAT3224 CAP FLAG + 0.55 F BAL CHRG LEDA FLASH TORCH RC RF 261 W 826 W Dual−Cell Supercapacitor 1 mF CN VIN – LEDB RT GND 2A 2A 562 W GND Figure 1. Typical Application Circuit Table 1. ABSOLUTE MAXIMUM RATINGS Parameter Rating Unit VIN, RC, RF, RT voltage GND−0.3 to 6 V CAP, CP, CN voltage GND−0.3 to 7 V CHRG, FLASH, TORCH, FLAG voltage (Note 1) GND−0.3 to 6 V GND−0.3 to CAP+0.3 V Storage Temperature Range −65 to +160 _C Junction Temperature Range −40 to +150 _C Lead Temperature 300 _C ESD Rating HBM (Human Body Model) 2000 V ESD Rating MM (Machine Model) 200 V BAL, LEDA, LEDB Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Table 2. RECOMMENDED OPERATING CONDITIONS Parameter Rating Unit VIN 2.0 to 5.5 V Ambient Temperature Range −40 to +85 _C LEDA, LEDB current (in flash mode) up to 2 A LEDA, LEDB current (in torch mode) 10 to 200 mA Input Current Limit up to 1 A FLAG pull−up resistor current 0 to 10 mA 1.3 to 4.2 V Range Unit 42 _C/W Range Unit 7 _C/W LED Forward Voltage Range (Vf) Table 3. PACKAGE THERMAL IMPEDANCE Parameter TQFN 3 mm x 3 mm 16−Lead qJA (Note 2) Table 4. PACKAGE TRANSIENT THERMAL IMPEDANCE Parameter TQFN 3 mm x 3 mm 16−Lead Transient qJA (Note 3) (100 ms pulse) 1. Pins can be driven above VIN with no leakage current or change in operation. 2. qJA (Junction to Ambient thermal resistance) is calculated with 2 square inches of copper connected to package exposed pad. 3. Transient qJA is calculated for a 100 ms pulse at 5 watts with 2 square inches of copper connected to package exposed pad. http://onsemi.com 2 CAT3224 Table 5. ELECTRICAL OPERATING CHARACTERISTICS (VIN = 3.6 V, EN = 1.3 V, TAMB = 25°C unless otherwise stated.) Symbol Name Conditions IQVIN Quiescent Current on VIN pin (IIN – 2 x IOUT) CAP Charged & idle 80 mA CAP Charging 2x Mode 6 mA CAP Charged & idle 10 mA Shutdown mode 3 mA Shutdown, VIN = 0 V 3 IQCAP Quiescent Current on CAP pin Min Typ IQSHDN Shutdown Current GFLASH Flash Gain (IFLASH / IRF) IFLASH = 2 A 900 GTORCH Torch Gain (ITORCH / IRT) ITORCH = 200 mA 120 Input Current Limit Gain (ICHRG / IRC) ICHARGE = 400 mA 400 GCHARGE VRX CHRG = FLASH = TORCH = 0 V RSET Regulated Voltage (VRF VRT VRC) IRX_MAX Rset Current limit (IRF IRT IRC) IRX = 0.1 mA 0.59 0.6 Max Units mA 1 mA 0.61 V VRX = 0 V 3.5 mA IIN_MAX Input current limit in charge mode VRC = 0 V 1.4 A VC_OFF CAP Charge off voltage RC = 2 kW 5.4 V VC_HYST CAP Charge Hysteresis 0.2 V VF_ON CAP voltage FLAG pulled low 5.2 V VF_HYST CAP voltage FLAG Hysteresis 0.2 V RLEDAB LEDA/B Combined Dropout Resistance IFLASHAB = 4 A 110 mW 1x mode 2 W 2x mode, VIN = 3.5 V 4 W Charge Pump Frequency 800 kHz TFLASH Flash Timeout Duration 300 ms VFLAG Flag low voltage threshold (Open Drain) REN VEHI VELO CHRG, FLASH, TORCH Pin Internal Pull−down Resistor Logic High Level Logic Low Level VBAL Active Balance Control (VCAP / 2) TSD Thermal Shutdown 150 °C THYS Thermal Hysteresis 20 °C VUVLO Undervoltage lockout (UVLO) threshold 1.9 V RCP FOSC Charge Mode Resistance FLAG Driven low 100 mA pull−up 0.2 V 0.4 kW V V +2 % 150 1.3 ±5 mA Load on BAL http://onsemi.com 3 −2 CAT3224 Cap Voltage and Flag Output The timing diagram in Figure 2 shows the CAP output voltage and the FLAG output in charge mode (with CHRG input high). CAP VOLTAGE VC OFF VC HYST VF ON VF HYST TIME Charge Current 0A FLAG FLASH LED Current 0A Figure 2. Supercapacitor Charge Timing Diagram http://onsemi.com 4 CAT3224 TYPICAL CHARACTERISTICS (VIN = 3.6 V, C = 0.55 F, TAMB = 25°C, typical application circuit unless otherwise specified.) 100 1.0 ICHARGE (A) IQVIN (mA) 90 80 70 60 3.0 3.5 4.0 4.5 5.0 0.1 5.5 RC (kW) Figure 3. Idle Quiescent Current vs. Input Voltage Figure 4. Charge Current vs. RC 10 ITORCH (mA) 1,000 1.0 0.1 1.0 100 10 10 0.1 1.0 RF (kW) RT (kW) Figure 5. Flash LED Current vs. RF Figure 6. Torch LED Current vs. RT 20 15 RDSON (W) IFLASH (A) 1.0 INPUT VOLTAGE (V) 10 0.1 0.1 10 5 0 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) Figure 7. FLAG RDSON vs. Input Voltage http://onsemi.com 5 5.5 10 CAT3224 TYPICAL CHARACTERISTICS 630 630 620 620 610 610 VRC (mV) VRF (mV) (VIN = 3.6 V, C = 0.55 F, TAMB = 25°C, typical application circuit unless otherwise specified.) 600 600 590 590 580 580 570 0 0.5 1.0 1.5 570 2.0 0 0.2 0.4 0.6 0.8 IFLASH (A) ICHARGE (A) Figure 8. VRF vs. IFLASH Figure 9. VRC vs. ICHARGE 630 1.0 6.0 620 5.5 VC_OFF (V) 600 590 5.0 4.5 580 570 0 50 100 150 4.0 200 0 0.5 1.0 1.5 2.0 ITORCH (mA) RC (kW) Figure 10. VRT vs. ITORCH Figure 11. VCAP idle vs. RC 500 400 IOUT (mA) VRT (mV) 610 300 200 Vled = 2.9 V 100 0 3.0 3.5 4.0 4.5 5.0 VCAP (V) Figure 12. Torch Output Current vs. VCAP http://onsemi.com 6 5.5 2.5 3.0 CAT3224 TYPICAL CHARACTERISTICS (VIN = 3.6 V, C = 0.55 F, TAMB = 25°C, typical application circuit unless otherwise specified.) CHRG 5V/div CHRG 5V/div CAP 2V/div CAP 2V/div Input Current Input Current 1A/div 500mA/div 1s/div 2s/div Figure 13. Charge Cycle, 1 A Input Current Figure 14. Charge Cycle, 500 mA Input Current CHRG 5V/div FLASH 5V/div CAP 2V/div LED Current 1A/div Input Current 500mA/ div 4s/div 40 ms/div Figure 15. Charge Cycle, 300 mA Input Current Figure 16. FLASH Transient Response CHRG 5V/div Input Current 500mA/div CAP 2V/div FLAG 5V/div 2s/div Figure 17. Charge Cycle with FLAG http://onsemi.com 7 CAT3224 Table 6. PIN DESCRIPTION Pin # Name Function 1 RF Flash Current Setting Resistor terminal 2 BAL Active Supercapacitor Balance Control 3, 4 CAP Supercapacitor Positive Connection 5 CHRG Charge Supercapacitor Enable 6 FLASH Flash Enable 7 TORCH Torch Enable 8 FLAG Flash Ready Flag output, Open drain (Active low) 9 LEDB LED B channel anode (+) connection 10 LEDA LED A channel anode (+) connection 11 RC Charge Current Setting Resistor terminal 12 RT Torch Current Setting Resistor terminal 13 VIN Positive supply connection to battery 14 CP Bucket capacitor Positive terminal 15 CN Bucket capacitor Negative terminal 16 GND Device ground connection TAB TAB Connect to GND on the PCB Pin Function RF is connected to a resistor (RF) to set the current in the LED channels in flash mode. The voltage on the pin is regulated to 0.6 V in flash mode (FLASH high). RT is connected to a resistor (RT) to set the current in the LED channels in torch mode. The voltage on the pin is regulated to 0.6 V in torch mode (TORCH high). RC is connected to a resistor (RC) to set the current limit on VIN when charging the supercapacitor. The voltage on the pin is regulated to 0.6 V in charge mode (CHRG high). CHRG is the charge mode enable pin. When high, the 1x/2x charge pump is enabled and allows to charge the supercapacitor and monitors its voltage. FLASH is the flash mode enable pin. When high, the LED current sources are enabled in flash mode. If FLASH is kept high for longer then 300 ms typical, the LED channels are automatically disabled. TORCH is the torch mode enable pin. When high, the LED current sources are enabled in torch mode. FLAG is an active−low open−drain output that notify to the microcontroller that the supercapacitor is fully charged by pulling the output low. When using the flag, this pin should be connected to a positive rail via an external pull−up resistor. VIN is the supply pin for the device and for the supercapacitor charger circuit. A small 1 mF ceramic bypass capacitor is required between the VIN pin and ground near the device. GND is the ground reference for the charge pump. This pin must be connected to the ground plane on the PCB. TAB is the exposed pad underneath the package. For best thermal performance, the tab should be soldered to the PCB and connected to the ground plane. CAP is the positive connection to the supercapacitor. Current sinks or sources from this pin to the capacitor depending on the mode of operation. CP, CN pins are connected to each side of the ceramic bucket capacitor used in the 2x charge pump mode. LEDA, LEDB are connected internally to the current sources and must be connected to the LED anodes. Each output is independently current regulated. These pins enter a high−impedance ‘zero’ current state whenever the device is placed in shutdown mode or FLASH and TORCH are low. BAL is connected to the center−point between the two supercapacitor cells. An active circuit forces the BAL pin to remain at half of the voltage of the CAP output. http://onsemi.com 8 CAT3224 Block Diagram Figure 18. Functional Block Diagram http://onsemi.com 9 CAT3224 Basic Operation The CAT3224 integrates in a single device two main functions: a dual cell supercapacitor charger and an LED driver. Two LED channels provide accurately regulated and matched current up to 2 A per channel. The charging mode is activated when the CHRG control input is pulled high and can remain active even during torch or flash mode. This allows continuous torch mode operation. The two modes, torch and flash, are activated using separate control inputs repectively TORCH and FLASH. current should be less than half the charging current. If the requested torch current is greater than half the input current, the LEDs will dim progressively according to the input current. Flash Mode When the FLASH input is set high, the driver is in flash mode and the LED channel current is set according to the external resistor connected between the RF pin and ground. The flash mode LED channel current can be calculated by the following equation (approximation). Charge Mode When the CHRG input is set high, the driver is in charge mode and the input supply current cannot exceed the current limit set by an external resistor connected between the RC pin and ground. The charging current limit is calculated by the following equation (approximation). I IN [ 400 I RC + 400 V RC + 400 RC I FLASH [ 900 0.6 V RC LED Current per Channel [A] RF [W] 1 549 1.5 360 2 261 The maximum flash duration where the LED current is regulated depends on the initial CAP voltage, capacitor value, LED forward voltage and the LED flash current setting. The flash pulse duration can be calculated as follows. T FLASH + C DV CAP I FLASH where C is the total supercapacitor value, ΔVCAP is the drop in the CAP voltage during the flash. See the Capacitor Selection section for more details. The RF pin has a current limit of 3.5 mA typical. If the RF pin is shorted to ground, the maximum flash LED current is 1000 x 3.5 mA or 3.5 A. During flash mode, the LEDs stay in regulation as long as their forward voltage does not exceed a maximum voltage calculated as follows: V Fmax + V CAP * IOUT The torch mode allows the LEDs to run for extended time duration but at a lower current than in the flash mode. When the TORCH input is set high, the driver is in torch mode and the LED channel current is set according to the external resistor connected between the RT pin and ground. The torch mode LED current per channel follows the equation: V RT + 120 RT 0.6 V RF Table 7. RSET Resistor Settings Torch Mode I RT + 120 V RF + 900 RF Table 7 shows some standard resistor values for RF and the corresponding LED channel current. If the CAP output voltage is lower than the charge threshold, the charging cycle starts. The driver charge pump initially starts in 1x mode and remains there as long as the supply voltage VIN is high enough to drive the CAP output voltage directly. In 1x mode, the output current charging the supercapacitor is approximately equal to the input current. The driver enters the 2x charge pump mode when the CAP pin voltage approaches VIN (VCAP ≈ VIN – 0.3 V). In 2x mode, the output current is approximately half of the input current. The charge cycle stops when either the CHRG input is pulled low or when the CAP output reaches the “CAP charge off voltage” threshold. As soon as the CAP output reaches the “CAP voltage FLAG pulled low” threshold, the FLAG output is pulled low. There is an hysteresis on the FLAG output which is illustrated in the timing diagram on Figure 2. The charge time is a function of the input voltage, input current setting, supercapacitor value, final CAP voltage. The RC pin has a current limit of 3.5 mA typical. If the RC pin is shorted to ground, the maximum charge current is 400 x 3.5 mA or 1.4 A. I TORCH [ 120 I RF + 900 ǒRCAP−ESR ) RLEDABǓ where IOUT is the CAP total output current, RCAP−ESR is the supercapacitor ESR (equivalent series resistance), and RLEDAB is the LEDA/B combined dropout resistance of the CAT3224. The transient waveform in Figure 19 shows the CAP output voltage during a 4 A flash pulse (2 A per LED channel) with CHRG low (not in charge mode). The initial drop on the CAP voltage (Vesr) is due to the supercapacitor ESR. In this example, it is calculated as follows. 0.6 V RT How long the LED current is regulated depends on the initial CAP voltage, capacitor value, the charge current, LED forward voltage and the LED torch current setting. In order to maintain regulation in 2x mode, the torch output Vesr + 2 http://onsemi.com 10 I LED R CAP−ESR + 2x 2A 0.1 W + 0.4 V CAT3224 To support 4 A flash pulses, we recommend using the 0.55 F supercapacitor HS206F from CAP−XX with a voltage rating of 5.5 V and a low ESR of 85 mΩ. In addition to the supercapacitor, a small 1 mF ceramic capacitor is recommended on the CAP output in order to filter out the charge pump switching noise due to the ESR of the supercapacitor. If a single cell supercapacitor is used, it is recommended to connect a small 1 mF ceramic capacitor between the BAL pin and GND. This will prevent any oscillation on the BAL pin and keep the quiescent current low. Thermal Dissipation Thermal dissipation occurs in the CAT3224 device due to the high current flowing in charge mode, as well as in torch or flash mode. During charge mode, in case the input voltage is high and the driver operates in 2x charge pump mode, the power dissipation may increase significantly. In torch and flash modes, the power dissipation is proportional to the difference between the CAP and LEDA/B pin voltages. If the junction temperature exceeds 150°C typical, the device goes into thermal shutdown mode and resumes normal operation as soon as the temperature drops by about 20°C. To improve the thermal performance, the TQFN exposed pad should be connected to the PCB ground plane underneath. Figure 19. CAP Output Transient during 4 A Flash Flash Rate Between two consecutive flash pulses, the supercapacitor needs some time to recharge. The supercapacitor time needed to fully recharge after a flash pulse is a function of the flash current and duration, and the charging current. Assuming the driver is in 2x mode, the charging time is calculated as follows. I OUT IIN T CHARGE + 2 T FLASH where IOUT is the total LED current, TFLASH is the flash duration and IIN is the input current. For example, a 60 ms 4 A flash pulse with a charge current of 300 mA corresponds to a recharge time: 4A 0.3 A T CHARGE + 2 Recommended Layout The ground side of the three current setting resistors, RC, RT, RF, should be star connected back to the GND of the PCB. In charge pump mode, the driver switches internally at a high frequency. Therefore it is recommended to minimize trace length to all four capacitors. A ground plane should cover the area under the driver IC as well as the bypass capacitors. Short connection to ground on capacitors CIN and COUT can be implemented with the use of multiple via. A copper area matching the TQFN exposed pad (TAB) must be connected to the ground plane underneath with a via. In order to minimize the IR drop in flash mode, the traces between the supercapacitor and the CAP pins, and between LEDA/LEDB pins and the LED(s) should be kept as short as possible and wide enough to handle the high current peaks. The supercapacitor negative terminal and the LED cathodes need to be connected to the ground plane directly. 0.06 s + 1.6 s Capacitor Selection The supercapacitor size depends on the flash requirement including flash duration, LED current and LED forward voltage. The minimum supercapacitor value is calculated as follows. C+ I OUT T FLASH V CAP * I OUTǒR CAP−ESR ) R LEDABǓ * V F where VCAP is the initial CAP voltage (5.2 V typical), and VF is the LED forward voltage. Any interconnection parasitic resistance is assumed negligible in the calculation. For example, for a 4 A flash with 0.1 s duration and 3.1 V LED VF, the minimum capacitor value is: C+ 4A 0.1 s 5.2 V * 4 Aǒ0.1 W ) 0.1 WǓ * 3.1 V ^ 0.3 F http://onsemi.com 11 CAT3224 PACKAGE DIMENSIONS TQFN16, 3x3 CASE 510AD−01 ISSUE A A D e b L E E2 PIN#1 ID PIN#1 INDEX AREA A1 TOP VIEW SYMBOL MIN SIDE VIEW NOM A 0.70 0.75 0.80 0.00 0.02 0.05 0.20 REF b 0.18 0.25 0.30 D 2.90 3.00 3.10 D2 1.40 −−− 1.80 E 2.90 3.00 3.10 E2 1.40 −−− 1.80 e L BOTTOM VIEW MAX A1 A3 D2 A FRONT VIEW 0.50 BSC 0.30 0.40 A3 A1 0.50 Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MO-220. http://onsemi.com 12 CAT3224 Example of Ordering Information (Note 4) 4. 5. 6. 7. 8. Prefix Device # Suffix CAT 3224 HV3 −G T2 Company ID (Optional) Product Number 3224 Package HV3: TQFN Lead Finish G: NiPdAu Tape & Reel (Note 8) T: Tape & Reel 2: 2,000 / Reel The device used in the above example is a CAT3224HV3−GT2 (TQFN, NiPdAu, Tape & Reel, 2,000 / Reel). All packages are RoHS−compliant (Lead−free, Halogen−free). The standard lead finish is NiPdAu. For additional package and temperature options, please contact your nearest ON Semiconductor sales office. For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. 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This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: [email protected] N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5773−3850 http://onsemi.com 13 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative CAT3224/D