MP2480DN-LF-Z

MP2480 5V―36V Input, 3A High Power LED Driver The Future of Analog IC Technology DESCRIPTION FEATURES The MP2480 is step-down switching regulator that delivers a constant current of up to 3A to high-power LEDs. It integrates a high-side, high-voltage power MOSFET with a current limit of 4.3A. The wide 5V to 36V input range accommodates a variety of step-down applications, making it ideal for general lighting and LCD backlighting applications. Hysteretic current-mode control helps provide for a very fast response, which makes the 20kHz dimming frequency possible. MPS’s proprietary feedback control minimizes the number of external components while delivering an LED current with a typical accuracy of ±3%. • • • • • • • • • The switching frequency goes up to 2MHz, thus permitting smaller components. Thermal shut down, and short circuit protection provide reliable fault-tolerant operation. A 160µA quiescent current allows for use in batterypowered applications. • • • The MP2480 is available in SOIC8-EP with an exposed pad on the bottom. • • Wide 5V to 36V Operating Input Range Up to 95% Efficiency Hysteretic Control with No Compensation No Output Capacitor Required ±3% LED Current Accuracy Up to 2MHz Switching Frequency Up to 20kHz Dimming Frequency 200mV Reference Voltage Short-Circuit Protection with Integrated High-Side MOSFET Thermal Shut Down Available in SOIC8-EP APPLICATIONS High Power LED Driver General Lighting and LCD Backlighting Constant Current Source All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 1 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER ORDERING INFORMATION Part Number Package Top Marking Free Air Temperature (TA) MP2480DN* SOIC8-EP MP2480 -40°C to +85°C * For Tape & Reel, add suffix –Z (e.g. MP2480DN–Z); For RoHS compliant packaging, add suffix –LF (e.g. MP2480DN–LF–Z) PACKAGE REFERENCE TOP VIEW SW 1 8 BST DIM 2 7 VIN EN 3 6 NC GND 4 5 FB EXPOSED PAD ON BOTTOM CONNECT TO GND SOIC8-EP (4) ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Supply Voltage (VIN)......................-0.3V to +40V Switch Voltage (VSW).......... -0.5V to (VIN + 0.5V) BST to SW ......................................-0.3V to +6V All Other Pins ..................................-0.3V to +6V Junction Temperature ...............................150°C Continuous Power Dissipation (TA = 25°C) (2) SOIC8-EP ................................................. 2.5W Lead Temperature ....................................260°C Storage Temperature............... -65°C to +150°C SOIC8-EP ...............................50 ...... 10 ... °C/W Recommended Operating Conditions (3) Supply Voltage VIN ..............................5V to 36V EN and DIM Voltages ...........................0V to 5V Maximum Junction Temp. (TJ) ..................125°C MP2480 Rev. 1.01 1/25/2013 θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ(MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD(MAX)=(TJ(MAX)TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7 4-layer board. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 2 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER ELECTRICAL CHARACTERISTICS VIN = 24V, TA= 25°C, unless otherwise noted. Specifications over temperature are guaranteed by design and characterization. Parameter Symbol Condition VIN UVLO threshold VIN UVLO hysteresis Shutdown supply current Quiescent supply current Upper switch on resistance (5) Upper switch leakage current Current limit EN up threshold EN threshold hysteresis EN input current EN sinking current DIM up threshold DIM threshold hysteresis RDS(ON) ISWLK IPK VENH VENHY IENI IENS VDIMH VDIMHY DIM input current IDIM Feedback voltage threshold high (5) VFBH Feedback voltage threshold low (5) VFBL FB pin input current Max duty cycle (5) Thermal shutdown IFB VEN = 0V No load, VFB = 250mV VBST – VSW = 5V VEN = 0V, VSW = 0V VFB = 0.15V Typ Max Units 3.6 4.0 0.4 2 160 150 0.01 4.3 1.55 320 0.01 2 1.15 300 4.4 1 -1 V V µA µA mΩ µA A V mV µA µA V mV µA µA 3.5 1.4 VEN =5V VEN =2V 0.8 VDIM =5V VDIM =0V 5V < VIN < 36V, VFB rising from 0V until VSW < 30V 5V < VIN < 36V, VFB falling from 0.25V until VSW > 30V VFB=5V or 0V DMAX (5) Min Hysteresis = 20°C -1 -5 5 220 1 1.7 1 3 1.5 220 225 230 mV 170 175 180 mV 100 nA -100 98 % 150 °C Note: 5) Guaranteed by design. MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 3 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER PIN FUNCTIONS SOIC8-EP Pin # Name 1 SW Switch Node. Output from the high-side switch. Requires a low-VF Schottky rectifier. Place the rectifier close to the SW pins to reduce switching spikes. 2 DIM PWM Dimming Input. Pull this pin below the specified threshold to turn dimming off. Pull this pin above the specified threshold to turn dimming on. If there is no need for dimming, connect DIM and EN pins together. 3 EN Enable Input. Pull this pin below the specified threshold to shutdown the chip. Pull this pin up above the specified threshold or leave it floating to enable the chip. 4 5 6 7 8 Description GND, Ground. Connect as close as possible to the output capacitor. Avoid the high-current Exposed switching paths. Connect exposed pad to GND plane for optimal thermal performance. pad Feedback. Input to hysteretic comparators. Connect an external current sensing resistor FB in series with the LEDs to GND. Connects with the feedback voltage; regulated at +200mV with 25% ripple. NC Not connected Input Supply. Supplies power to all the internal control circuitry, including both bootstrap VIN regulators and the high-side switch. Place a decoupling capacitor to ground close to this pin to minimize switching spikes. Bootstrap. Positive power supply for the internal floating high-side MOSFET driver. BST Connect a bypass capacitor between this pin and SW pin. MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 4 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER BLOCK DIAGRAM VIN IENS Internal Regulators Reference UVLO EN Control Logic and Protection Circuits DIM VFBH R FB S IPK SW Q VFBL 200mV BST Adaptive Threshold Adjustment Circuit GND VFBH VFBL Figure 1—Functional Block Diagram MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 5 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER TYPICAL CHARACTERISTICS RDS_ON vs. Temperature Current Limit vs. Temperature 5 4.5 250 4 200 3.5 3 150 2.5 100 2 1.5 1 50 0.5 0 -50 -30 -10 10 30 50 70 90 110 130 IQ vs.Temperature 0 -50-30 -10 10 30 50 70 90 110130 Average Voltage of FB vs. Temperature 208 175 170 204 165 160 200 155 150 196 145 140 135 -50 -30 -10 10 30 50 70 90 110 130 MP2480 Rev. 1.01 1/25/2013 192 -50 -30 -10 10 30 50 70 90 110 130 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 6 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER TYPICAL PERFORMANCE CHARACTERISTICS L=47μH, VIN=30V, ILED=2A, 7 LED Load, TA=25°C, unless otherwise noted. Efficiency vs. LED Number VIN=36V 2 100 1.8 98 1.6 96 1.4 94 EFFICIENCY (%) LED CURRENT (A) PMW Dimimg Cure 1.2 1 0.8 2kHz 200Hz 0.6 0.4 0.2 0 0 92 90 88 86 84 82 0.2 0.4 0.6 0.8 1 8 1 2 PMW DUTY 4 5 6 7 8 9 LED NUMBER VSW 20V/div. VSW 20V/div. VSW 20V/div. VIN 20V/div. VIN 20V/div. VIN 20V/div. VLED 20V/div. VLED 20V/div. VLED 20V/div. ILED 1A/div. ILED 1A/div. ILED 1A/div. VSW 20V/div. VSW 20V/div. VSW 20V/div. VEN 5V/div. VEN 5V/div. VDIM 2V/div. VLED 20V/div. VLED 20V/div. ILED 1A/div. ILED 1A/div. MP2480 Rev. 1.01 1/25/2013 3 VLED 20V/div. ILED 1A/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 7 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER TYPICAL PERFORMANCE CHARACTERISTICS (continued) L=47μH, VIN=30V, ILED=2A, 7 LED Load, TA=25°C, unless otherwise noted. VSW 20V/div. VSW 20V/div. VEN 2V/div. VIN 20V/div. VLED 20V/div. VLED 20V/div. ILED 1A/div. MP2480 Rev. 1.01 1/25/2013 ISHORT 1A/div. VSW 20V/div. ISHORT 1A/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 8 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER OPERATION Hysteresis Current Control with Adaptive Threshold Adjustment MP2480 operates in a hysteretic current-control mode to accurately regulate the LED current. The sensing resistor (RFB) connects to the FB pin to sense the LED current. The power MOSFET turns on and remains on until the voltage on the FB pin rises to the upper threshold of 225mV. The power MOSFET then turns off and remains off until FB pin falls to the lower threshold of 175mV. The two thresholds are adaptive and adjust to compensate for circuit delay. This regulates the LED current very accurately with an average of 200mV at the FB pin. Enable Control The MP2480 has a dedicated enable-control pin (EN) with positive logic. Its falling threshold is 1.23V, and its rising threshold is 1.55V (320mV higher). When floating, EN pulls up to about 3.0V by an internal 1µA current source so it is enabled. Pulling down a floating EN requires a current capability of 1µA.. Under-Voltage Lockout (UVLO) Under-voltage lockout (UVLO) protects the chip from operating at insufficient supply voltage. The UVLO rising threshold is about 4.0V while its falling threshold is a consistent 3.6V. Thermal Shutdown Thermal shutdown prevents the chip from operating at exceedingly high temperatures. When the silicon die temperature rises above its upper threshold, the chip shuts down. When the temperature falls below its lower threshold, the chip is enabled again. LED Short Protection The LED current is within its limits and wellregulates while FB pin voltage is 200mV, as long as RFB has not failed. If the LED sensing resistor has failed or the output has shorted to GND, the voltage of FB pin falls. VIN charges the inductor. When the inductor current reaches the current limit value, the power MOSFET turns off. MP2480 will retry the operation after about 300µs delay. Floating Driver and Bootstrap Charging The floating power MOSFET driver is powered by an external bootstrap capacitor. This floating driver has its own UVLO protection, with a rising threshold of 2.2V and a falling threshold of 150mV. The dedicated internal bootstrap regulator charges and regulates the bootstrap capacitor to around 5V. In case the internal circuit does not have sufficient voltage and the bootstrap capacitor has insufficient charge, extra external circuitry can ensure that the bootstrap voltage is in the normal operational region. Refer to External Bootstrap Diode in the Application section. MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 9 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER APPLICATION INFORMATION COMPONENT SELECTION Input Capacitor CIN Setting the LED Current The input current to the step-down converter is discontinuous, and therefore requires a capacitor to supply the AC current to the stepdown converter and maintain the DC input voltage. Use low-ESR capacitors for best performance, especially for high-switching– frequency applications. RFB is connected in series to the LEDs and sets the LED current, ILED. The FB pin connects to the voltage on the sensing resistor RFB, where. ILED = VFB RFB For example, for ILED = 700mA, RFB = 286mΩ. Inductor Selection and Frequency Setting The inductor L supplies a constant current to the LED. The inductor value is related to the switching frequency (fs) setting: fs = (VIN − VOUT ) ⋅ VOUT VIN ⋅ L ⋅ ILED ⋅ 25% Where VIN is the input voltage, and VOUT is the output voltage that drives the LEDs. A largervalue inductor will result in smaller switching frequency. The peak inductor current is about: ILP = ILED ⋅ 1.125 Choose an inductor that will not saturate under the maximum inductor peak current. Output Rectifier Diode The output rectifier diode supplies the current to the inductor when the high-side switch is off. To reduce losses due to the diode’s forward voltage and recovery times, use a Schottky diode. The RMS current through the diode is about: ID = ILED ⋅ 1 − VOUT VIN Choose a diode with a maximum reverse voltage rating greater than the maximum input voltage, and a current rating greater than the maximum diode current. MP2480 Rev. 1.01 1/25/2013 The RMS current through the input capacitor is about: ID = ILED ⋅ VOUT ’ VIN With low ESR capacitors, the input voltage ripple can be estimated as: ΔVIN = ⎛ V V ⎞ ILED × OUT × ⎜ 1 − OUT ⎟ fs × CIN VIN ⎝ VIN ⎠ Choose the input capacitor with a high-enough RMS current rating and enough capacitance for a small input-voltage ripple. Include a small high-quality ceramic capacitor (0.1μF) placed as close to the IC as possible when using electrolytic or tantalum capacitors. Output Capacitor COUT The output capacitor (COUT) is not necessary to reduce the LED ripple current: The LED ripple current (peak-to-peak value) is about 15% of the LED DC current. However, the output capacitor can be used to further reduce the LED ripple current. Use low-ESR capacitors to limit the output ripple voltage. The output ripple voltage can be estimated by: ΔVOUT = VOUT ⎛ V × ⎜ 1 − OUT fS × L ⎝ VIN ⎞ ⎞ ⎛ 1 ⎟ ⎟ × ⎜ RESR + 8 × fS × COUT ⎠ ⎠ ⎝ Where RESR is the equivalent series resistance (ESR) value of the output capacitor. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 10 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER External Bootstrap Diode Layout Consideration An external bootstrap diode may enhance the efficiency of the LED driver. For the cases listed below, add an external BST diode is from a 5V rail to the BST pin: Place the input decoupling capacitors and the catch diode as close to MP2480 (VIN pin, SW pin and PGND) as possible, with short, wide traces. This reduces the voltage spike on the SW node and lowers the EMI noise level. z There is a 5V rail available in the system; z VIN ≤ 5V; z 3.3V < VOUT < 5V; Add a diode for high duty cycle operations (when VOUT/VIN > 65%), and for very-high– frequency (over 1.5MHz) applications. The bootstrap diode can be low-cost, such as a IN4148 or BAT54. Run the feedback trace as far away from the inductor and noisy power traces as possible. Try to run the feedback trace on the opposite side of the PCB to the inductor, with a ground plane separating the traces from the inductor. To improve thermal conduction, create a grid of thermal vias right under the exposed pad. Use small vias (15mil barrel diameter) so that the holes fill during the plating process. Very large holes can cause ‘solder-wicking’ problems during the reflow soldering process. Use a pitch (distance between the centers) of around 40mil to space the vias. Figure 2—External Bootstrap Diode MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 11 MP2480 – 36V INPUT, 3A HIGH POWER LED DRIVER PACKAGE INFORMATION SOIC8-EP 0.189(4.80) 0.197(5.00) 0.124(3.15) 0.136(3.45) 8 5 0.150(3.80) 0.157(4.00) PIN 1 ID 1 0.228(5.80) 0.244(6.20) 0.089(2.26) 0.101(2.56) 4 TOP VIEW BOTTOM VIEW SEE DETAIL "A" 0.051(1.30) 0.067(1.70) SEATING PLANE 0.000(0.00) 0.006(0.15) 0.013(0.33) 0.020(0.51) 0.0075(0.19) 0.0098(0.25) SIDE VIEW 0.050(1.27) BSC FRONT VIEW 0.010(0.25) x 45o 0.020(0.50) GAUGE PLANE 0.010(0.25) BSC 0.050(1.27) 0.024(0.61) 0o-8o 0.016(0.41) 0.050(1.27) 0.063(1.60) DETAIL "A" 0.103(2.62) 0.138(3.51) RECOMMENDED LAND PATTERN 0.213(5.40) NOTE: 1) CONTROL DIMENSION IS IN INCHES. DIMENSION IN BRACKET IS IN MILLIMETERS. 2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. 4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.004" INCHES MAX. 5) DRAWING CONFORMS TO JEDEC MS-012, VARIATION BA. 6) DRAWING IS NOT TO SCALE. 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. MP2480 Rev. 1.01 1/25/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 12