CAT4139

CAT4139 22 V High Current Boost White LED Driver Description The CAT4139 is a DC/DC step−up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a fixed switching frequency of 1 MHz allows the device to be used with small value external ceramic capacitors and inductor. LEDs connected in series are driven with a regulated current set by the external resistor R1. The CAT4139 is ideal for driving parallel strings of up to five white LEDs in series or up to 22 V. LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power−down mode with “zero” quiescent current. In addition to thermal protection and overload current limiting, the device also enters a very low power operating mode during “Open LED” fault conditions. The device is housed in a low profile (1 mm max height) 5−lead TSOT−23 package for space critical applications. Features http://onsemi.com 5 1 TSOT−23 TD SUFFIX CASE 419AE PIN CONNECTIONS 1 SW GND FB (Top View) SHDN VIN • • • • • • • • • • • • Switch Current Limit 750 mA Drives LED Strings up to 22 V Up to 87% Efficiency Low Quiescent Ground Current 0.6 mA 1 MHz Fixed Frequency Low Noise Operation Soft Start “In−rush” Current Limiting Shutdown Current Less than 1 mA Open LED Overvoltage Protection Automatic Shutdown at 1.9 V (UVLO) Thermal Overload Protection TSOT−23 5−Lead (1 mm Max Height) These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant MARKING DIAGRAM TPYM TP = Specific Device Code Y = Production Year (Last Digit) M = Production Month (1−9, A, B, C) ORDERING INFORMATION Device CAT4139TD−GT3 (Note 1) Package TSOT−23 (Pb−Free) Shipping 3,000/ Tape & Reel Applications • GPS Navigation Systems • Portable Media Players • Handheld Devices 1. NiPdAu Plated Finish (RoHS−compliant) © Semiconductor Components Industries, LLC, 2010 February, 2010 − Rev. 1 1 Publication Order Number: CAT4139/D CAT4139 VIN 5V C1 4.7 mF VIN CAT4139 OFF ON SHDN GND L: Sumida CDRH6D28−220 D: Central CMSH1−40 (rated 40 V) FB R2 (300 mV) 1 kW L 22 mH C2 SW 1 mF 35 V IOUT 180 mA R1 1.62 W D VOUT 9 strings at 20 mA Figure 1. Typical Application Circuit Table 1. ABSOLUTE MAXIMUM RATINGS Parameters VIN, FB Voltage SHDN Voltage SW Voltage Storage Temperature Range Junction Temperature Range Lead Temperature Ratings −0.3 to +7 −0.3 to +7 −0.3 to +40 −65 to +160 −40 to +150 300 Units V V V _C _C _C 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 (Typical application circuit with external components is shown above.) Parameters VIN SW pin voltage Ambient Temperature Range (Note 2) Range up to 5.5 0 to 22 −40 to +85 Units V V _C 2. TSOT23−5 package thermal resistance qJA = 135°C/W when mounted on board over a ground plane. http://onsemi.com 2 CAT4139 Table 3. DC ELECTRICAL CHARACTERISTICS (VIN = 3.6 V, ambient temperature of 25°C (over recommended operating conditions unless otherwise specified)) Symbol IQ ISD VFB IFB ILED VIH VIL FSW ILIM RSW ILEAK TSD THYST VUVLO VOV−DET VOCL DC Parameter Operating Current Shutdown Current FB Pin Voltage FB pin input leakage Programmed LED Current SHDN Logic High SHDN Logic Low Switching Frequency Switch Current Limit Switch “On” Resistance Switch Leakage Current Thermal Shutdown Thermal Hysteresis Under−voltage lock out (UVLO) Threshold Over−voltage detection threshold Output Clamp voltage Maximum duty cycle Minimum duty cycle “Open LED” 23 VIN = 3.6 V VIN = 5 V ISW = 100 mA Switch Off, VSW = 5 V R1 = 10 W R1 = 3 W Enable Threshold Level Shutdown Threshold Level 28.5 30 100 0.8 0.7 1.0 Test Conditions VFB = 0.2 V VFB = 0.4 V (not switching) VSHDN = 0 V 9 x 3 LEDs, IOUT = 180 mA 285 Min Typ 0.6 0.1 0.1 300 Max 1.5 0.6 1 315 1 31.5 1.5 1.3 Units mA mA mV mA mA V MHz mA 1.0 1 150 20 1.9 24 29 92 16 2.0 5 W mA °C °C V V V % 0.4 0.8 600 750 http://onsemi.com 3 CAT4139 TYPICAL CHARACTERISTICS (VIN = 5.0 V, IOUT = 180 mA, TAMB = 25°C, with typical application circuit unless otherwise specified.) 200 VFB = 0.4 V QUIESCENT CURRENT (mA) 5.5 QUIESCENT CURRENT (mA) 1.5 2.0 150 1.0 100 0.5 50 3.0 3.5 4.0 4.5 5.0 0 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Figure 2. Quiescent Current vs. VIN (Not Switching) 303 302 FB PIN VOLTAGE (mV) FB PIN VOLTAGE (mV) 305 301 300 299 298 297 −50 0 50 TEMPERATURE (°C) 100 150 290 80 310 Figure 3. Quiescent Current vs. VIN (Switching) 300 295 100 120 140 160 180 200 OUTPUT CURRENT (mA) Figure 4. FB Pin Voltage vs. Temperature 1.2 SWITCHING FREQUENCY (MHz) SWITCH RESISTANCE (W) 2.0 Figure 5. FB Pin Voltage vs. Output Current 1.1 1.5 1.0 1.0 0.9 0.5 0.8 3.0 3.5 4.0 4.5 5.0 5.5 0 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Figure 6. Switching Frequency vs. Supply Voltage Figure 7. Switch ON Resistance vs. Input Voltage http://onsemi.com 4 CAT4139 TYPICAL CHARACTERISTICS (VIN = 5.0 V, IOUT = 180 mA, TAMB = 25°C, with typical application circuit unless otherwise specified.) 200 180 160 140 120 100 2.0 1.5 IOUT VARIATION (%) 5.5 LED CURRENT (mA) 1.0 0.5 0 −0.5 −1.0 −1.5 3.0 3.5 4.0 4.5 5.0 −2.0 4.5 4.7 4.9 5.1 5.3 5.5 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Figure 8. Output Current vs. Input Voltage 95 95 Figure 9. Output Current Regulation 90 EFFICIENCY (%) EFFICIENCY (%) 90 IOUT = 120 mA 85 85 IOUT = 180 mA 80 80 75 80 100 120 140 160 180 200 75 4.5 4.7 4.9 5.1 5.3 5.5 OUTPUT CURRENT (mA) INPUT VOLTAGE (V) Figure 10. Efficiency vs. Output Current Figure 11. Efficiency vs. Input Voltage Figure 12. Power−up at 180 mA Figure 13. Switching Waveform http://onsemi.com 5 CAT4139 TYPICAL CHARACTERISTICS (VIN = 5.0 V, IOUT = 180 mA, TAMB = 25°C, with typical application circuit unless otherwise specified.) 300 MAX OUTPUT CURRENT (mA) SHUTDOWN VOLTAGE (V) 250 VOUT = 9 V 200 150 VOUT = 14 V 100 50 0 1.0 0.8 −40°C −25°C 0.6 85°C 125°C 0.4 3.0 3.5 4.0 4.5 5.0 5.5 0.2 3.0 3.5 4.0 INPUT VOLTAGE (V) 4.5 5.0 INPUT VOLTAGE (V) Figure 14. Maximum Output Current 900 SWITCH CURRENT LIMIT (mA) 850 800 VOUT = 12 V 750 700 650 600 VOUT = 9 V Figure 15. Shutdown Voltage 4.5 4.7 4.9 5.1 5.3 5.5 INPUT VOLTAGE (V) Figure 16. Switch Current Limit http://onsemi.com 6 CAT4139 Pin Description VIN is the supply input for the internal logic. The device is compatible with supply voltages down to 2.8 V and up to 5.5 V. It is recommended that a small bypass ceramic capacitor (4.7 mF) be placed between the VIN and GND pins near the device. If the supply voltage drops below 1.9 V, the device stops switching. SHDN is the shutdown logic input. When the pin is tied to a voltage lower than 0.4 V, the device is in shutdown mode, drawing nearly zero current. When the pin is connected to a voltage higher than 1.5 V, the device is enabled. GND is the ground reference pin. This pin should be connected directly to the ground plane on the PCB. SW pin is connected to the drain of the internal CMOS power switch of the boost converter. The inductor and the Schottky diode anode should be connected to the SW pin. Traces going to the SW pin should be as short as possible with minimum loop area. An over−voltage detection circuit is connected to the SW pin. When the voltage reaches 24 V, the device enters a low power operating mode preventing the SW voltage from exceeding the maximum rating. FB feedback pin is regulated at 0.3 V. A resistor connected between the FB pin and ground sets the LED current according to the formula: I LED + 0.3 V R1 The lower LED cathode is connected to the FB pin. Table 4. PIN DESCRIPTIONS Pin # 1 2 3 4 5 Name SW GND FB SHDN VIN Function Switch pin. This is the drain of the internal power switch. Ground pin. Connect the pin to the ground plane. Feedback pin. Connect to the last LED cathode. Shutdown pin (Logic Low). Set high to enable the driver. Power Supply input. VIN SW C1 1 MHz Oscillator – + + – Thermal Shutdown & UVLO Current Sense PWM & Logic Driver ILED Over Voltage Protection VOUT C2 Ref 300 mV Figure 17. Simplified Block Diagram http://onsemi.com 7 – SHDN + VIN RS GND FB CAT4139 Device Operation The CAT4139 is a fixed frequency (1 MHz), low noise, inductive boost converter that provides a constant current with excellent line and load regulation. The device uses a high−voltage CMOS power switch between the SW pin and ground to energize the inductor. When the switch is turned off, the stored energy in the inductor is released into the load via the Schottky diode. The on/off duty cycle of the power switch is internally adjusted and controlled to maintain a constant regulated voltage of 0.3 V across the feedback resistor connected to the feedback pin (FB). The value of the resistor sets the LED current accordingly (0.3 V/R1). During the initial power−up stage, the duty cycle of the internal power switch is limited to prevent excessive in−rush Application Information External Component Selection Capacitors currents and thereby provide a “soft−start” mode of operation. In the event of an “Open LED” fault condition, where the feedback control loop becomes open, the output voltage will continue to increase. Once this voltage exceeds 24 V, an internal protection circuit will become active and place the device into a very low power safe operating mode. Thermal overload protection circuitry has been included to prevent the device from operating at unsafe junction temperatures above 150°C. In the event of a thermal overload condition the device will automatically shutdown and wait till the junction temperatures cools to 130°C before normal operation is resumed. The CAT4139 only requires small ceramic capacitors of 4.7 mF on the input and 1 mF on the output. Under normal condition, a 4.7 mF input capacitor is sufficient. For applications with higher output power, a larger input capacitor of 10 mF may be appropriate. X5R and X7R capacitor types are ideal due to their stability across temperature range. Inductor forward voltage should be as low as possible. The response time is also critical since the driver is operating at 1 MHz. Central Semiconductor Schottky rectifier CMSH1−40 (1 A rated) is recommended for most applications. LED Current Setting A 22 mH inductor is recommended for most of the CAT4139 applications. In cases where the efficiency is critical, inductances with lower series resistance are preferred. Inductors with current rating of 800 mA or higher are recommended for most applications. Sumida CDRH6D28−220 22 mH inductor has a rated current of 1.2 A and a series resistance (D.C.R.) of 128 mW typical. Schottky Diode The LED current is set by the external resistor R1 connected between the feedback pin (FB) and ground. The formula below gives the relationship between the resistor and the current: R1 + 0.3 V LED current Table 5. RESISTOR R1 AND LED CURRENT LED Current (mA) 20 25 30 100 300 R1 (W) 15 12 10 3 1 The current rating of the Schottky diode must exceed the peak current flowing through it. The Schottky diode performance is rated in terms of its forward voltage at a given current. In order to achieve the best efficiency, this http://onsemi.com 8 CAT4139 Open LED Protection In the event of an “Open LED” fault condition, the CAT4139 will continue to boost the output voltage with maximum power until the output voltage reaches approximately 24 V. Once the output exceeds this level, the internal circuitry immediately places the device into a very low power mode where the total input power is limited to about 6 mW (about 1.6 mA input current with a 3.6 V supply). The SW pin clamps at a voltage below its maximum rating of 40 V. There is no need to use an external zener diode between VOUT and the FB pin. A 35 V rated C2 capacitor is required to prevent any overvoltage damage in the open LED condition. Schottky 40 V (Central CMSH05−4) L VIN 22 mH C2 1 mF D VOUT C1 4.7 mF VIN SW CAT4139 OFF ON SHDN GND FB R1 15 W Figure 18. Open LED Protection Circuit Figure 19. Open LED Disconnect and Reconnect 2.5 35 Figure 20. Open LED Disconnect INPUT CURRENT (mA) OUTPUT VOLTAGE (V) 3.0 3.5 4.0 4.5 5.0 5.5 30 2.0 25 1.5 20 1.0 15 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Figure 21. Open LED Supply Current Figure 22. Open LED Output Voltage http://onsemi.com 9 CAT4139 Dimming Control There are several methods available to control the LED brightness. PWM Signal on the SHDN Pin Filtered PWM Signal LED brightness dimming can be done by applying a PWM signal to the SHDN input. The LED current is repetitively turned on and off, so that the average current is proportional to the duty cycle. A 100% duty cycle, with SHDN always high, corresponds to the LEDs at nominal current. Figure 23 shows a 1 kHz signal with a 50% duty cycle applied to the SHDN pin. The recommended PWM frequency range is from 100 Hz to 2 kHz. A filtered PWM signal used as a variable DC voltage can control the LED current. Figure 24 shows the PWM control circuitry connected to the CAT4139 FB pin. The PWM signal has a voltage swing of 0 V to 2.5 V. The LED current can be dimmed within a range from 0 mA to 20 mA. The PWM signal frequency can vary from very low frequency and up to 100 kHz. VIN SW CAT4139 PWM Signal 2.5 V 0V VIN SHDN GND RA 3.73 kW C3 0.22 mF RB 3.1 kW FB VFB = 300 mV R2 1 kW LED Current R1 15 W Figure 24. Circuit for Filtered PWM Signal A PWM signal at 0 V DC, or a 0% duty cycle, results in a max LED current of about 22 mA. A PWM signal with a 93% duty cycle or more, results in an LED current of 0 mA. 25 Figure 23. Switching Waveform with 1 kHz PWM on SHDN LED CURRENT (mA) 20 15 10 5 0 0 10 20 30 40 50 60 70 80 90 100 PWM DUTY CYCLE (%) Figure 25. Filtered PWM Dimming (0 V to 2.5 V) http://onsemi.com 10 CAT4139 Board Layout The CAT4139 is a high-frequency switching regulator. The traces that carry the high-frequency switching current have to be carefully laid out on the board in order to minimize EMI, ripple and noise in general. The thicker lines on Figure 26 show the switching current path. All these traces have to be short and wide enough to minimize the parasitic inductance and resistance. The loop shown on Figure 26 corresponds to the current path when the CAT4139 internal switch is closed. On Figure 27 is shown L VIN SW VIN CAT4139 SHDN C1 GND Switch Closed VIN CAT4139 FB C2 R1 C1 SHDN Switch Open D V OUT VIN SW the current loop, when the CAT4139 switch is open. Both loop areas should be as small as possible. Capacitor C1 has to be placed as close as possible to the VIN pin and GND. The capacitor C2 has to be connected separately to the top LED anode. A ground plane under the CAT4139 allows for direct connection of the capacitors to ground. The resistor R1 must be connected directly to the GND pin of the CAT4139 and not shared with the switching current loops and any other components. L D VOUT FB C2 R1 GND Figure 26. Closed−switch Current Loop Figure 27. Open−switch Current Loop Figure 28. Recommended PCB Layout http://onsemi.com 11 CAT4139 PACKAGE DIMENSIONS TSOT−23, 5 LEAD CASE 419AE−01 ISSUE O SYMBOL A A1 A2 b c D E1 E E E1 e L L1 L2 0.30 0.01 0.80 0.30 0.12 0.15 2.90 BSC 2.80 BSC 1.60 BSC 0.95 TYP 0.40 0.60 REF 0.25 BSC 0.50 0.05 0.87 D e MIN NOM MAX 1.00 0.10 0.90 0.45 0.20 θ TOP VIEW 0º 8º A2 A q b A1 L1 L c L2 SIDE VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-193. END VIEW http://onsemi.com 12 CAT4139 Example of Ordering Information (Note 5) Prefix CAT Device # 4139 Suffix TD −G T3 Company ID (Optional) Product Number 4139 Package TD: TSOT−23 Lead Finish G: NiPdAu Tape & Reel (Note 7) T: Tape & Reel 3: 3,000 / Reel SERIES LED DRIVERS Part Number CAT4137 CAT4237 CAT4238 CAT4139 CAT4240 Description CMOS Boost Converter − White LED Driver ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Á High Voltage CMOS Boost White LED Driver High Efficiency 10 LED Boost Converter 22 V High Current Boost White LED Driver 6 Watt Boost LED Driver 3. 4. 5. 6. 7. 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: orderlit@onsemi.com 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 All packages are RoHS−compliant (Lead−free, Halogen−free). The standard lead finish is NiPdAu. The device used in the above example is a CAT4139TD−GT3 (TSOT−23, NiPdAu, Tape & Reel, 3,000/Reel). 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. ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative http://onsemi.com 13 CAT4139/D