MP1519DQ

TM MP1519 1x, 1.5x, 2x High Efficiency Charge Pump 4 White LED Driver The Future of Analog IC Technology TM DESCRIPTION The MP1519 is a fully automatic driver for powering four white LEDs, with up to 4V forward voltage, from a single Li-Ion or three NiMH cells. The driver performs all of the sensing and control to run the LEDs at an optimum charge pump ratio for efficiency without an expensive inductor. The driver allows PWM operation to support brightness control. The tiny 3mm x 3mm QFN16 package and small external capacitors allow for the most compact white LED solution available. FEATURES • • • • • • • • • • • • • • • • 2% LED Current Matching High Efficiency (>93%) Current Source Outputs No Ballast Resistors Required 1x, 1.5x and 2x Automatic Modes Constant Frequency Operation Automatic LED Detection High and Low Frequency PWM Capability 2.5V to 5.5V Operation Less than 1µA Leakage during Shutdown Detects Changes in Battery Level No External Schottky Diode Required Soft-Start and Soft Switching Operation Cell Phones PDA or Hand Held Computers White LED Application at 3.6V Supply EVALUATION BOARD REFERENCE Board Number EV0042 Dimensions 2.4”X x 1.9”Y x 0.4”Z APPLICATIONS “MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MP1519 BATT ENABLE 5, 13 BATT C1A 4 Efficiency vs Supply Voltage 100 90 80 EFFICIENCY (%) 12 EN C1B 7 VLED = 3.35V @ 20mA ILED=5mA ILED=20mA 11 RADJ C2A 6 70 60 50 40 30 20 10 0 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) 4.5 ILED=10mA GND 3, 10 GND C2B LED1 LED2 9 14 15 16 1 8 LEDC LED3 LED4 LED4 LED3 LED2 LED1 MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 1 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER PACKAGE REFERENCE PIN 1 ID ABSOLUTE MAXIMUM RATINGS (1) VBATT to GND .............................................. 6.5V Power Dissipation (QFN) ........................... 1.0W Logic Inputs to GND ................... –0.3V to +6.5V Storage Temperature ..............–65°C to +150°C Junction Temperature...............................150°C TOP VIEW LED3 LED2 LED1 BATT 16 15 14 13 12 11 10 9 5 BATT LED4 NC GND C1A 1 2 3 4 6 C2A EN RADJ GND C2B Recommended Operating Conditions (2) Input Voltage VBATT ...................... 2.5V to 5.5V Operating Temperature .............–40°C to +85°C 7 8 Thermal Resistance (3) C1B LEDC EXPOSED PAD CONNECT TO PIN 8 3x3 QFN16 ............................. 60 ...... 14... °C/W Temperature Notes: 1) Exceeding these ratings may damage the device. 2) The device is not guaranteed to function outside of its operating conditions. 3) Measured on approximately 1” square of 1 oz copper. θJA θJC Part Number* MP1519DQ * Package QFN16 (3mm x 3mm) –40°C to +85°C For Tape & Reel, add suffix –Z (eg. MP1519DQ–Z) For RoHS Compliant Packaging, add suffix –LF (eg. MP1519DQ–LF–Z) ELECTRICAL CHARACTERISTICS VBATT = 5V, TA = +25°C, unless otherwise noted. Parameter Input Supply Voltage VBATT at 1x to 1.5x Mode Switch VBATT at 1.5x to 2x Mode Switch VBATT at 2x to 1.5x Mode Switch VBATT at 1.5x to 1x Mode Switch Supply Current Supply Current Shutdown Current Matching (4) Enable Voltage, High Enable Voltage, Low Enable Pin Leakage Charge Pump Frequency Time to Standby Mode (5) Enable Pin PWM Frequency Limit LED Current Symbol VBATT VBATT 1x-1.5x VBATT 1.5x-2x VBATT 2x-1.5x VBATT 1.5x-1x IBATT IBATT SHDN ILED MATCH VEN (HIGH) VEN (LOW) IEN FCP TOFF FHPWM ILED Condition ILED = 20mA, VBATT Decreasing, VLED = 3.35V @ 20mA ILED = 20mA, VBATT Decreasing, VLED = 3.35V @ 20mA VBATT Increasing, VLED = 3.35V @ 20mA VBATT Increasing, VLED = 3.35V @ 20mA 4 LEDs at 20mA, 2x Mode, VBATT = 2.5V VEN = 0V ILED = 20mA 0.8 VEN = 5V VBATT = 3.3V Enable Switched Low RSET = 1.54kΩ 1.0 Min 2.5 Typ 3.6 2.8 3.1 3.8 164 0.1 1.5 2.0 1.0 0.1 1.3 30 50 20 180 1 5.0 2.2 1 1.6 Max 5.5 Units V V V V V mA µA % V V µA MHz µs KHz mA 18 22 Notes: 4) Matching is defined as the difference of the maximum to minimum current divided by the sum of the maximum and minimum currents. 5) Standby mode switches to shutdown when the output voltage on LEDC drifts back to GND. MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 2 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER TYPICAL PERFORMANCE CHARACTERISTICS Voltage Ripple in 1.5x Mode 4 x 10mA LEDs VBATT 20mV/div. VLEDC 20mV/div. 400ns/div. Startup in 1.5x Mode 4 x 10mA LEDs Startup in 1x Mode 4 x 10mA LEDs VEN 5V/div. VEN 5V/div. IBATT 100mA/div. IBATT 100mA/div. Analog Dimming 16 14 LED CURRENT (mA) Circuit of Figure 3, VBATT = 3.6V 12 11 10 9 8 7 LED Current Matching LED4 LED3 12 10 8 6 4 2 0 0 1 2 DC VOLTAGE (V) 3 LED CURRENT (mA) LED2 LED1 6 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) 4.5 MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 3 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER PIN FUNCTIONS Pin # 1 2 3, 10 4 5, 13 6 7 8 9 11 12 14 15 16 Name Description LED4 NC GND C1A BATT C2A C1B LEDC C2B RADJ EN LED1 LED2 LED3 #4 LED Driver. Connect the #4 LED between LED4 and LEDC, with the anode at LED4, and the cathode at LEDC. If the #4 LED is not used, leave LED4 unconnected. No Connect. Ground. Charge Pump Capacitor #1 Positive Node. Connect the positive side of the #1 charge pump capacitor to C1A. Typical applications require C1 to be 1µF. Battery Power Input. Connect the 2.5V to 5.5V input source between BATT and GND. Bypass BATT to GND with a 1µF or greater capacitor. Charge Pump Capacitor #2 Positive Node. Connect the positive side of the #2 charge pump capacitor to C2A. Typical applications require C2 to be 1µF. Charge Pump Capacitor #1 Negative Node. Connect the negative side of the #1 charge pump capacitor to C1B. LED Common for the Cathodes. Connect the cathodes of the LEDs to LEDC and to a 4.7µF bypass capacitor. Do not connect to any other ground, supply or pin. Note: Exposed pad on backside is connected to this pin. Do Not Ground. Charge Pump Capacitor #2 Negative Node. Connect the negative side of the #2 charge pump capacitor to C2B. LED Current Adjust Input. Connect a resistor between RADJ and GND to set the LED current. All of the LEDs regulate at the same current. See Setting the LED Current. Enable Input. Drive EN high to turn on the MP1519, drive EN low to shutdown the MP1519. To use burst-mode brightness control, drive EN with a PWM signal. See Burst Mode Dimming. #1 LED Driver. Connect the #1 LED between LED1 and LEDC, with the anode at LED1, and the cathode at LEDC. If the #1 LED is not used, leave LED1 unconnected. #2 LED Driver. Connect the #2 LED between LED2 and LEDC, with the anode at LED2, and the cathode at LEDC. If the #2 LED is not used, leave LED2 unconnected. #3 LED Driver. Connect the #3 LED between LED3 and LEDC, with the anode at LED3, and the cathode at LEDC. If the #3 LED is not used, leave LED3 unconnected. MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 4 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER OPERATION The MP1519 is a charge pump that drives 4 LEDs from a 2.5V to 5.5V input voltage. It automatically switches between 1x, 1.5x and 2x charge pump modes to optimize efficiency while maintaining LED current regulation. Four drivers independently regulate the current through the LEDs, therefore matching LEDs are not required. The MP1519 employs soft switching and soft-start to prevent overloading the battery source at turn-on and charge pump mode switching. While operating, the MP1519 continually monitors the LED current and battery voltage and automatically switches between charge pump modes to retain LED current regulation through all LEDs as the battery voltage fluctuates. BATT BATT 5, 13 FAULT BATTERY SENSOR CURRENT SOURCE LED1 14 FAULT CURRENT SOURCE LED2 15 ENABLE EN 12 CONTROLLER FAULT CURRENT SOURCE LED3 16 SHUTDOWN FAULT LED ENABLE CURRENT SOURCE LED4 1 RADJ 11 CURRENT GENERATOR ISET LED4 LED3 LED2 LED1 PUMP SOFT MODE START LEDC 8 C1A 1.25V BANDGAP REFERENCE CHARGE PUMP 4 C1B 7 C2A GND 3, 10 6 C2B 9 Figure 1—Functional Block Diagram MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 5 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER APPLICATION INFORMATION COMPONENT SELECTION Startup When power is applied to the BATT, driving EN high will enable the MP1519. The MP1519 begins by checking for open LEDs and determining the optimum charge pump mode. The lowest charge pump mode that allows the programmed LED current in all LEDs is set. This will occur during initial turn-on or during analog mode and burst mode dimming. Shutdown Driving EN low for more than 30µs will disable the MP1519. For safety the MP1519 runs a small supervisory circuit in standby to protect the charge pump output LEDC. The circuit shuts down when the charge pump output returns to zero volts (this can take a few seconds). The MP1519 is in true shutdown mode when LEDC is zero and the 30µs time interval has passed. The supply current should be less than 1µA. Setting the LED Current The LED regulation current is set through the resistor R1 (refer to the typical application circuit on page 1). The voltage across R1 is fixed at 1.25V, and the current through that resistor sets the current through the LEDs. Figure 2 shows LED Current (ILED) vs. R1 with VBATT = 3.6V. 25 LED CURRENT (mA) Choose R1 for the desired LED current according to the equation: R1 = 31.25 ILED Where R1 is in kΩ, and ILED is in mA. Suitable values for R1 are greater than 1.2kΩ. Soft-Start During startup and mode switching, an internal soft-start prevents excessive input current, preventing excessive loading of the battery or input power source. Burst Mode Dimming To dim the part using burst mode, drive EN with a PWM signal. Each time EN is driven high, the MP1519 goes through the initial startup routine and checks for open LEDs, and the charge pump step-up mode is reset. When EN goes low, the LED current immediately goes to zero. After EN is held low for 30µs or longer, and LEDC falls below GND, the MP1519 operating current drops below 1µA to improve battery life. Maintain the frequency of the PWM signal between 50Hz and 50KHz. Going above 50KHz the accuracy of the PWM signal will be degraded due to the startup time, and below 50Hz, the LED flicker will be evident to the eye. Ideally, the LED current increases proportionally with the duty cycle of the PWM signal and is independent of the dimming frequency. Analog Mode Dimming Analog dimming can be accomplished with the circuit in Figure 3. The circuit provides 1mA to 15mA dimming with VDC = 0 to 3V. The minimum LED current the MP1519 can regulate is approximately 1mA. LEDC Do not drive or force LEDC as it may be shorted to ground or may be pumped down by the controller in the MP1519 at any time. Excessive capacitance on the LEDC node can cause the internal controller to time out before the charge pump can be ready. Missing the timeouts will cause excessive pumping and a loss of efficiency. The MP1519 requires C1 and C2 be of the same value and type. 6 20 15 10 5 0 0 5 10 15 20 Figure 2—ILED vs. R1 MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER TYPICAL APPLICATION CIRCUITS MP1519 BATT ENABLE VDC 0V to 3V GND 5, 13 BATT C1A 4 12 EN C1B 7 11 RADJ C2A 6 3, 10 GND C2B 9 LED1 14 LED2 8 15 LEDC LED3 LED4 16 1 LED4 LED3 LED2 LED1 Figure 3—Analog Dimming Circuit MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 7 TM MP1519 – 1X, 1.5X, 2X CHARGE PUMP 4 WHITE LED DRIVER PACKAGE INFORMATION QFN16 (3mm x 3mm) 2.90 3.10 PIN 1 ID MARKING 0.18 0.30 PIN 1 ID INDEX AREA 2.90 3.10 0.50 BSC 9 0.30 0.50 13 1.50 1.80 16 PIN 1 ID SEE DETAIL A 1 1.50 1.80 4 12 8 5 TOP VIEW BOTTOM VIEW PIN 1 ID OPTION A 0.30x45º TYP. 0.80 1.00 0.00 0.05 PIN 1 ID OPTION B R0.20 TYP. 0.20 REF SIDE VIEW DETAIL A 2.90 1.70 0.70 0.25 NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX. 4) DRAWING CONFORMS TO JEDEC MO-220, VARIATION VEED-4. 5) DRAWING IS NOT TO SCALE. 0.50 RECOMMENDED LAND PATTERN NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP1519 Rev. 1.9 7/27/2006 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2006 MPS. All Rights Reserved. 8