WLED Driver
The Future of Analog IC Technology
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION-TCL USE ONLY
DESCRIPTION The MP4012 is a current mode controller designed for driving the high brightness Light Emitting Diodes (LEDs) from extremely wide input voltage 8V~90V. It can be used in Boost, Buck, Buck-boost and SEPIC topologies. The MP4012 drives external MOSFET with fixed frequency/constant off-time architecture to regulate the LED current, which is measured through an external current sense resistor. Its feedback voltage can be adjusted by the external DC bias voltage. The MP4012 can work in constant frequency operation mode or constant off time mode, which contains the programmable slope compensation and optimizes the control loop regulation and avoids sub harmonic oscillation. The MP4012 implements high frequency PWM Dimming with external disconnect MOSFET. And achieves analog dimming by adjusted the feedback voltage. The MP4012 has synchronous function, which makes Multiple ICs synchronize each other by connecting SYNC pins together. The MP4012 includes under-voltage lockout, over voltage protection, open and short hiccup mode protection, overload protection and thermal protection to prevent damage in the case of fault condition. The MP4012 is available in a 16-pin SOIC package. FEATURES
• Constant-current WLED Driver • 8V~90V Input Voltage • Constant Frequency Mode Or Constant Off Time Mode • Programmable Switching Frequency or Off-time • Leading Edge Blanking for Current Sense • High Frequency PWM Dimming and Analog Dimming • Output-to-Input Disconnect in Shutdown Mode • Synchronization function • Programmable Over Voltage Protection • Open Load Hiccup Mode Protection • Short Load Hiccup Mode Protection • Programmable Current Limit • UVLO, Thermal Shutdown • Soft Start • Available in 16-pin SOIC package APPLICATIONS • LED Lamp applications • DC/DC LED Driver applications • General Illumination • Industrial Lighting • Automotive/ Decorative LED Lighting “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. ADAM (Analog Digital Adaptive Modulation), AAM (….) areTrademarks of Monolithic Power Systems, Inc. The MP#### is covered by US Patents #,###,###, #,###,###, #,###,###. MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
TYPICAL APPLICATION
L1
D1
VINCINM1VINGATER1R2COUTCDDVDDCSRCS2RCS1PWM DIMCCOMPPWMGNDSYNCOVPCOMPFAULTM2CREFREF7FBRFBISETSLRSET2RSET1CLRTRSLRCL2RTRCL1MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
ORDERING INFORMATION Free Air Temperature (TA) Part Number* Package Top Marking MP4012ES SOIC16 –20°C to +85°C * For Tape & Reel, add suffix –Z (eg. MP####XX–Z); For RoHS, compliant packaging, add suffix –LF (eg. MP####XX–LF–Z). PACKAGE REFERENCE TOP VIEW VIN116FBVDD2GATEGNDCSSLRTSYNC34567815ISET14COMP13PWM12OVP11FAULT109REFCL ABSOLUTE MAXIMUM RATINGS (1) VIN............... ...... ... .... .................–0.5V to 100V VDD................................................–0.5V to 13.5V VGATE, VFAULT...................... ..–0.5V to VDD+0.3V All Other Pins ..............................–0.3V to 6.5V Junction Temperature...............................150°C Lead Temperature....................................260°C (2) Continuous Power Dissipation (TA = +25°C) ..........................................................TBD W Thermal Resistance (4)θJA θJC PACKAGE ...........................TBD...TBD.°C/W 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-to-ambient 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 PCB.
Recommended Operating Conditions IN Supply Voltage VIN .........................8V to 90V Operating Junction Tempe.....–20°C to +125°C
(3)MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
ELECTRICAL CHARACTERISTICS VIN =24V, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Min TypMaxUnitsOperating Input Voltage VDD Voltage Supply Current (Shutdown) VDD Under Voltage Lockout Under Voltage Lockout Hysteresis VDD(external) Internal Regulator Reference Voltage Reference Line Regulation Reference Load Regulation PWM Dimming PWM Low Threshold PWM High Threshold PWM Pull-down Resistance Gate GATE Short Circuit Current GATE Sink Current GATE Output Rise Time GATE Output Fall Time Current Sense Leading Edge Blanking Delay to Output of COMP Comparator Delay to Output of CLIMIT Comparator Comparator Offset Voltage Oscillator Oscillator Frequency Oscillator Frequency Maximum Duty Cycle SYNC Input High SYNC Input Low SYNC Output Current Slope Compensation Current Source Out of SL Pin Internal Current Mirror Ratio Over Voltage Protection OVP Threshold OVP Threshold Hysteresis MP4012 Rev. 0.1 8/4/2010
VIN VVDD ISD UVLO 8 90 V VIN > 8V, VEN = 3V 7.25 7.758.25V VPWM = 0V 1.0 1.5 mAVDD Rising 6.65 6.907.20V 500 mV=Connect external DC voltage 12 V ===VREF 1.225 1.251.275V 0.1uF bypassed capacitor, 0 20 mVVREFLINE IREF=0 VDD=7.25-12V 0.1uF bypassed capacitor, 0 10 mVVREFLOAD IREF=0-500uA VPWMI-LO VPMWI Falling 0.8 V VPWMI-HI VPMWI Rising 1.5 V RPWM 50 100150k Ω ISOURCE VGATE=0V, VDD7.75V 0.2 A ISINK VGATE=7.75V, VDD7.75V 0.4 A TRISE CGATE=1nF, VDD7.75V 50 85 ns TFALL CGATE=1nF, VDD7.75V 25 45 ns TBLANK TDELAY1 TDELAY2 VOFFSET 100 250ns 200ns 200ns -10 10 mVfOSC1 RT=96kΩ 510 580650kHzfOSC2 RT=500kΩ 99 106118kHzDMAX 87 90 93 % VSYNCH 1.5 VSYNCL 0.8 ISYNC 18 uA ISLOPE GSLOPE ISLOPE=50uA, RSL=1k Ω VOVP-TH 0 100uA 1.8 2.0 2.2 1.215 1.25 1251.285 V mV4
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
ELECTRICAL CHARACTERISTICS (CONTINUED) VIN =24V, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Min TypMaxUnitsOutput Short Circuit Protection Gain for Short Circuit Comparator GSC 1.9 2.0 2.1 ISET=200mV, FB=450mV, Propagation time for short circuit TOFF 250ns detection FAULT goes form high to low 330pF capacitor at FAULT Fault Output Rise Time TRISE 300ns pin 330pF capacitor at FAULT Fault Output Fall Time TFALL 200ns pin Short Circuit Detecting Blanking Time TSC_BT 500 700ns Current Source/Sink at COMP Pin for 5.0 uA IHICCUP Hiccup Mode Protection Thermal Shutdown (5) Notes: 5) Guaranteed by design 150 °C MP4012 Rev. 0.1
8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
PIN FUNCTIONS Pin # 1 Name IN Pin Function Input Supply Pin. It is the input of internal linear regulator. Must be locally bypassed. The Internal Linear Regulator Output Pin. VDD provides power supply for the external2 VDD MOSFET gate driver and the internal control circuitry .Bypass VDD to GND with a ceramic capacitor. 3 GATE External MOSFET Gate Driver Pin. 4 GND Ground. Current Sense Input Pin. It is used to sense the current of the external power FET. It has5 CS a built-in 100ns (min) blanking time. Slope compensation Pin for current sense. Connected a resistor between SL and GND 6 SL programs the slope compensation. In case of constant off-time mode of operation, slope compensation is unnecessary and let this pin open. Switching frequency/off-time set Pin. A resistor connected between this pin and GND or 7 RT GATE sets the frequency/off-time. Synchronization Pin. Connecting the multiple MP4012SYNC pins together to achieve the 8 SYNC synchronous working mode. Current Limit Set Pin. This pin set the external MOSFET current limit. The current limit can 9 CL be set by using a resistor divider from the REF pin to GND. Soft start can also be implemented on this pin. Reference Output Pin. A ceramic capacitor should be connected to bypass this pin to 10 REF GND. Fault Indication Output Pin. Thispin is pulled down to GND in case of short circuit 11 FAULT condition or over voltage condition. It is also used to driver the external MOSFET to disconnect the load from Vin for boost converter. Over Voltage Protection Input Pin. Connect a resistor divider from output to this pin to 12 OVP program the OVP threshold. When the voltage of this pin reaches 1.25V, the MP4012 triggers over voltage protection. PWM Dimming Input Pin. Apply a PWM signal on this pin for brightness control.The 13 PWM GATE is disabled when PWM signal is low. The GATE is enabled when PWM signal is high. Converter Compensation Pin.This pin is used to compensate the regulation control loop. Connect a capacitor or a series RC network from COMP to GND. COMP pin is also used 14 COMP for fault timer. When IC start up or short protection is triggered, the 5uA current source charge COMP pint untilreached 5V, then 5uA current sink discharge COMP voltage, IC is active when COMP voltage reduce to 1V. LED Current Set Pin. Connect a resistor divider from REF pin to set the LED current 15 ISET reference. The analog dimming function can be achieved through adjusting thevoltage on ISET pin. Feedback Input Pin. The MP4012regulates the voltage across the current sense resistor. 16 FB Connect a current sense resistor from FB to GND. The regulation voltage is set by ISET pin. MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
OPERATIONThe MP4012 drives external MOSFET with current mode architecture to regulate the LED current, which is measured through an external current sense resistor. Figure 1 shows the functional block diagram. MP4012 employs a special circuit for regulating the internal power supply, which covers a wide input voltage from 8V to 90V. The 7.75V linear regulator provides all the power for internal circuits and external MOSFET gate drive energy. MP4012 has a 2% accurate 1.25V reference, which is used as the reference for LED current. The reference is also used to set the current limit and over voltage threshold. GATE pin sets the off time for CT mode. For constant switching frequency mode, MP4012 includes a slope compensation section to ensure the converter stability when duty cycle is greater than 0.5. For synchronization, the SYNC pins of multiple MP4012 can be connected together, and may also be connected to the open drain output of a master clock. When connected in this manner, the oscillators will lock to the device with the highest operating frequency. MP4012 has two high-speed current comparators. One is used during normal operation, which contains an internal 100ns blanking time to MP4012 can be programmed as constant prevent the current spike from mis-triggering the switching frequency (CF) or constant off time (CT) comparator. The other is used to limit the operation. Connecting a resistor between RT pin maximum input current, which is programmable and GND sets the switching frequency for CF by connecting a resistor mode. Connecting a resistor between RT pin and divider from REF. REFVbgLinear RegulatorPORSSVINVDDSSCLGATERCSQFAULTBlankSSlope CompensationQRSSQSPORThermal ProtectionGNDSC1.25VOVPFBISETBlankRTOne ShotCOMPDimming/Hiccup ProtectionSYNCPWM2 Figure 1—Functional Block Diagram
MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
Start up
The start up process is shown in figure 2. During start up, the COMP is charged to 5V first, then it is discharged by an internal current source, MP4012 is active until the COMP voltage is VINdischarged to 1V. The high level Fault turns on the external disconnected MOSFET. The output current is regulated by the converter. VCC5VCOMP1VFaultIoutFigure 2— Start up Process Analog Dimming Analog dimming can be accomplished by varying the voltage at the ISET pin. This can be done either by using resistor divider from the REF pin or by applying an external DC voltage at the ISET pin. disconnecting MOSFET can prevent the output voltage from being discharged, which helps to achieve the high frequency PWM dimming with better linear dimming performance. Protection MP4012 includes short circuit protection and over PWM Dimming voltage protection, If the fault conditions are PWM dimming can be achieved by applying a detected (either short circuit or open circuit), the square wave signal on PWM pin. The PWM COMP pin is disconnected from the internal EA signal controls the internal error amplifier (EA), and the Gate and Fault pins are pulled down to FAULT output and GATE output. When the PWM disable the LED driver, once the fault is remove, signal is high, the GATE and FAULT pins are the COMP pin is charged by an internal current enabled, and the output of the EA is connected to source until it reaches 5V, then the COMP is the external compensation network. So the LED discharged by an internal current source. When it current is regulated accurately. When the PWM reaches 1V, the current source is disconnected signal goes low, the GATE signal is disable. And from COMP pin and the internal EA is connected the FAULT pin is pulled down to GND to turn off to it, the Fault pin starts to go high and the Gate the disconnecting MOSFET. Meanwhile the pin is allowed to switch. output of the EA is disconnected from the compensation network. Thus, the COMP voltage can be hold by external capacitor. And the
MP4012 Rev. 0.1 8/4/2010
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
The short circuit threshold current is internally set to 200% of the steady state current. When the output current becomes higher than the short circuit threshold after some delay, the short circuit protection circuit is activated. See the figure 3. This allows the LED drive system auto-restart in a accident short condition without having to reset the IC. The open load protection is achieved though detecting the OVP pin voltage. When open load fault occurs, the output voltage rises as the output capacitor is still charged. The over voltage protection turns off the MP4012 and takes FAULT
Short Loadto GND when the OVP pin exceeds 1.25V The converter turns on when the output voltage falls below the falling OVP threshold. MP4012 will repeat the process until the open load fault is removed. When recovering from the open load condition, the output current might have some spike which caused by the high output voltage, and trigger the short load protection. But it can enter normal work mode when output voltage is close to the normal value. See figure 4. OutputVoltageOpen LoadOpen Load RecoverOVP-HOVP-LVout-normalOutput CurrentShort Load RecoverNormal Current5V5VCOMP1VCOMP1VOutput CurrentNormal CurrentFaultHiccup Time Figure 3— Hiccup Mode Short Load ProtectionFault Figure 4— Open Load Protections MP4012 Rev. 0.1 8/4/2010 www.MonolithicPower.com
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MP4012 HIGH-VOLTAGE, HIGH-CURRENT ACCURACY WLED DRIVER
PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION- TCL USE ONLY
PACKAGE INFORMATION
SOIC16 0.386( 9.80)0.394(10.00)1690.063(1.60)0.150(3.80)0.157(4.00)0.228(5.80)0.244(6.20)0.024(0.61)0.050(1.27)PIN 1 ID0.213(5.40)18TOP VIEWRECOMMENDED LAND PATTERN0.053(1.35)0.069(1.75)SEATING PLANE0.013(0.33)0.020(0.51)0.050(1.27)BSC0.004(0.10)0.010(0.25)SEE DETAIL \"A\"0.0075(0.19)0.0098(0.25)FRONT VIEWSIDE VIEW0.010(0.25)x 45o0.020(0.50)GAUGE PLANE0.010(0.25) BSCNOTE: 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 AC. 6) DRAWING IS NOT TO SCALE.0o-8o0.016(0.41)0.050(1.27)DETAIL \"A\"
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications. 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.
MP4012 Rev. 0.1 8/4/2010
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