MP3302(MP3302).pdf-资料库

第1页 / 共11页

第2页 / 共11页

第3页 / 共11页

第4页 / 共11页

第5页 / 共11页

第6页 / 共11页

第7页 / 共11页

第8页 / 共11页

The Future of Analog IC Technology MP3302 1.3A Fixed Frequency White LED Driver MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY Internal Power MOSFET FEATURES • • Drives up to 10 Series White LEDs • Up to 87% Efficiency • 1.3MHz Fixed Switching Frequency • Open Load Shutdown • Low 195mV Feedback Voltage • UVLO, Thermal Shutdown • Internal 1.33A Current Limit • Available in TSOT23-5 and QFN8 2mm x 3mm Packages APPLICATIONS • 5” ~ 7” LCD Panels • Handheld Computers and PDAs • Digital Still Cameras • Small LCD Displays “Monolithic Power Systems”, “MPS”, and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. DESCRIPTION The MP3302 is a step-up converter designed for driving up to 27 white LEDs, 3 WLEDs in series 9 strings, all from a single cell Lithium Ion battery. The MP3302 uses current mode, fixed frequency architecture to regulate the LED current, which is measured through an external current sense resistor. Its low 195mV feedback voltage reduces power loss and improves efficiency. The MP3302 is turned off if an over-voltage condition is present due to an open circuit condition. The MP3302 includes under-voltage lockout, current limiting and thermal overload protection preventing damage in the event of an output overload. The MP3302 is available in small 5-pin TSOT23 and 8-pin QFN (2mm x 3mm) packages. TYPICAL APPLICATION VIN 3.3V - 6V Enable/ Dimming Control String 1 ... String 9 LED1 LED2 LED3 SW IN EN MP3302 GND FB LED25 LED26 LED27 Efficiency vs Input Voltage 3 WLEDs,9 Strings 3 4 5 INPUT VOLTAGE(V) ) % ( I Y C N E C F F E I 95 90 85 80 75 70 65 60 1 6 MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved.

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY PACKAGE REFERENCE TOP VIEW SW GND FB 1 2 3 5 IN 4 EN TOP VIEW GND IN NC EN 1 2 3 4 8 7 6 5 SW NC FB GND Part Number* Package Temperature MP3302DJ TSOT23-5 –40°C to +85°C Part Number** MP3302DD Package QFN8 Temperature (2mm x 3mm) –40°C to +85°C * For Tape & Reel, add suffix –Z (eg. MP3302DJ–Z) For RoHS Compliant Packaging, add suffix –LF (eg. MP3302DJ–LF–Z) ABSOLUTE MAXIMUM RATINGS (1) SW Pin.........................................–0.5V to +40V All Other Pins..............................–0.3V to +6.5V Storage Temperature.............. –55°C to +150°C Recommended Operating Conditions (2) IN Supply Voltage ..............................2.5V to 6V SW Pin................................................VIN to 36V Operating Temperature............. –40°C to +85°C ** For Tape & Reel, add suffix –Z (eg. MP3302DD–Z) For RoHS Compliant Packaging, add suffix –LF (eg. MP3302DD–LF–Z) Thermal Resistance (3) TSOT23-5.............................. 220.... 110.. °C/W QFN8 (2mm x 3mm)............... 80...... 16... °C/W θJC θJA 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. ELECTRICAL CHARACTERISTICS VIN = VEN = 5V, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Operating Input Voltage Supply Current (Shutdown) Supply Current (Quiescent) Switching Frequency Maximum Duty Cycle Under Voltage Lockout IN Under Voltage Lockout Under Voltage Lockout Hysteresis Open Lamp Shutdown Threshold VEN = 0V VFB = 0.15V VFB = 0V VIN Rising VIN fSW VOV Rising UVLO VOV Min 2.5 1.0 92 Typ Max Units V 6 µA 8 µA 850 1.5 MHz % 4 690 1.3 2.25 2.45 92 38 V mV V MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 2

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY VEN Falling VEN Rising VFB = 0V ELECTRICAL CHARACTERISTICS (continued) VIN = VEN = 5V, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Enable EN OFF Threshold EN ON Threshold Minimum EN Dimming Threshold Maximum EN Dimming Threshold Feedback FB Voltage FB Input Bias Current Output Switch SW On-Resistance (4) SW Current Limit (4) Thermal Shutdown (4) Notes: 4) Guaranteed by design. Duty Cycle = 60% VEN = 1.5V VFB = 0.1V VFB = 0.2V RON Min Typ Max Units 0.4 -600 0.7 1.4 195 -300 0.5 1.33 150 0.6 V V V V mV nA Ω A °C PIN FUNCTIONS TSOT23-5 Pin # QFN8 Pin # Name Pin Function 1 2 3 4 5 MP3302 Rev. 0.94 8/2/2007 8 SW Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the power inductor and output rectifier to SW. SW can swing between GND and 36V. 1, 5 GND Ground. FB EN Feedback Input. The MP3302 regulates the voltage across the current sense resistor between FB and GND. Connect a current sense resistor from the bottom of the LED string to GND. Connect the bottom of the LED string to FB. The regulation voltage is 195mV. ON/OFF Control and Dimming Command Input. A voltage greater than 0.6V will turn the part on and less than 0.4V will turn the part off. If the EN pin voltage is between 0.7V and 1.4V, VFB is regulated between 0V and 195mV. To use PWM dimming, apply a 200Hz to 1KHz square wave signal with amplitude greater than 1.5V to this pin. Input Supply Pin. Must be locally bypassed. IN NC No Connect. 6 4 2 3 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 3

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5V, 3WLEDs 9Strings, unless otherwise noted. Efficiency vs Input Voltage Steady State Operation Enable Startup VIN = 5V, 3 WLEDs,9 Strings VIN = 5V, 3 WLEDs,9 Strings VSW 10V/div. VFB 50mV/div. VOUT AC Coupled 100mV/div. Iinductor 500mA/div. VSW 10V/div. VEN 2V/div. VOUT 5V/div. ILED 100mA/div. 3 WLEDs,9 Strings 6 WLEDs 8 WLEDs ) % ( I Y C N E C F F E I 95 90 85 80 75 70 65 60 3 10WLEDs 4 5 6 400ns/div. INPUT VOLTAGE(V) Enable Shutdown Start Up into Openload PWM Dimming VIN = 5V, 3 WLEDs,9 Strings VIN = 5V VIN = 5V, 3 WLEDs,9 Strings VSW 10V/div. VEN 2V/div. VOUT 5V/div. ILED 100mA/div. VSW 20V/div. VEN 5V/div. VOUT 20V/div. Output Current vs Analog Dimming Voltage VIN=5V, 3 WLEDs, 9 Strings VSW 10V/div. VEN 5V/div. VOUT 5V/div. ILED 100mA/div. 1 Output Current vs PWM Dimming Duty VIN=5V, 3 WLEDs, 9 Strings f=1kHz 0 0.4 0.2 PWM DIMMING DUTY 0.8 ) A m ( T N E R R U C T U P T U O 200 180 160 140 120 100 80 60 40 20 0 ) A m ( T N E R R U C T U P T U O 200 180 160 140 120 100 80 60 40 20 0 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 EN PIN VOLTAGE (V) MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 4

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY OPERATION The MP3302 uses a constant frequency, peak current mode boost regulator architecture to regulate the series string of white LEDs. The operation of the MP3302 can be understood by referring to the block diagram of Figure 1. At the start of each oscillator cycle the FET is turned on through the control circuitry. To prevent sub-harmonic oscillations at duty cycles greater than 50 percent, a stabilizing ramp is added to the output of the current sense amplifier and the result is fed into the positive input of the PWM comparator. When this voltage equals the output voltage of the error amplifier the power FET is turned off. FB EN - + AMPLIFIER 195mV for Full Brightness - + PWM COMPARATOR ENABLE & DIMMING CONTROL + Enable 1.3MHz OSC The voltage at the output of the error amplifier is an amplified version of the difference between the 195mV reference voltage and the feedback voltage. In this way the peak current level keeps the output in regulation. If the feedback voltage starts to drop, the output of the error amplifier increases. This results in more current flowing through the power FET, thus increasing the power delivered to the output. CONTROL LOGIC M1 SW + - CURRENT SENSE AMPLIFIER Figure 1—Functional Block Diagram MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. GND 5

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY APPLICATION INFORMATION VIN 3.3V to 6V 4.7uH MBR0520 C1 10uF Enable/ Dimming Control IN EN GND MP3302 SW FB C2 0.47uF Figure 2—Circuit for Driving 9 Strings of 3 WLEDs low is sufficient capacitor A typical application circuit can be seen in Figure 2. The 9 strings of 3 white LEDs can be driven from a voltage supply range of 3.3V to 6V at an output current of 180mA. A 0.47µF output for most applications. A 4.7µH inductor with low DCR (Inductor DC resistance) is recommended to improve efficiency. A 10µF ceramic capacitor is recommended for the input capacitance in the real system. Schottky diodes have fast recovery and a voltage and are recommended. Schottky diodes rated with 500mA are sufficient for the MP3302. The MP3302 has internal soft-start to limit the amount of current through VIN at startup and to also limit the amount of overshoot on the output. The ramped voltage that is added to the current sense amplifier reduces the current output as the duty cycle increases. As more LEDs are added, the output voltage rises but the current that can be delivered to the load is reduced as well. forward Setting the LED Current The LED current is controlled by the feedback resistor, R1. The current through the LEDs is given by the equation 195mV/R1. Table 1 shows the selection of resistors for a given LED current. Table 1—ILED vs. R1 ILED (mA) 1 5 10 20 60 180 R1 (Ω) 195 39 19.5 9.75 3.25 1.08 MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 6

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY LED Current Programming Applying a DC voltage between 0.7V and 1.4V to EN pin programs a feedback voltage between 0V and 195mV. Thus the analog dimming of LED current can be achieved. The DC dimming voltage must be locally bypassed to prevent noise interfering with the feedback reference level. PWM Dimming Apply a 200Hz to 1kHz square waveform to the EN pin to implement PWM dimming of the LEDs. The minimum recommended amplitude of the PWM signal is 1.5V. For high frequency PWM dimming (>1kHz), it is also recommended that the dimming control be implemented as shown in Figure 3. The cut off frequency of the RC filter should be 10 times lower than that of the input PWM signal. For example, when the PWM frequency is 20kHz, a 20kΩ resistor and 100nF capacitor can be used. The DC voltage on EN pin is then equal to the PWM high level voltage multiplies the PWM duty. The DC voltage from 0.7V to 1.4V programs the output current from 0~100%. LED1 LED2 LED3 PWM MP3302 EN FB Open Load Protection Open Load protection will shut off the MP3302 if the output voltage goes too high. In some cases an LED may fail, this will result in the feedback voltage always being zero. The part will run at maximum duty cycle boosting the output voltage higher and higher. If the output ever exceeds 38V, the MP3302 will shut down. The part will not switch again until the power is recycled. Layout Considerations Careful attention must be paid to the PCB board layout and components placement. Proper layout of the high frequency switching to prevent noise and path electromagnetic interference problems. The current loop of IC, output diode, and output capacitor should be as short as possible. The IN pin of the IC must be locally bypassed. A RC for eliminating the noise on IN pin. It could be implemented as shown in Figure 4. recommended is critical filter is highly Input IN SW MP3302 GND Figure 4—Input Bias Filtering Figure 3—High Frequency PWM Dimming Control MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 7

MP3302 – 1.3A FIXED FREQUENCY WHITE LED DRIVER MPS CONFIDENTIAL AND PROPRIETARY INFORMATION – HUAWEI USE ONLY TYPICAL APPLICATION CIRCUITS D1 B0540 Optional Bias Circuit 2 IN 8 SW 4 EN MP3302 6 FB GND 1 D2 5.6V ZENER L1 4.7uH/1A C1 4.7uF 16V C3 0.1uF 50V VIN 3.3V -18V EN GND C4 330nF 50V LED+ LED- Figure 5 — Driving 27 WLEDs (9 WLEDs in Series and 3 Strings Paralleled) with 3.3V―18V Input Voltage In order to improve the MOSFET on-resistance at low input voltage and make the chip compatible for high input voltage, the additional bias circuit should be used. VIN 4.5V-16V C1 4.7uF 16V EN GND D2 5.6V ZENER Q2 2N3904 C3 0.1uF 25V Required Bias Circuit for High Input Voltage L1 4.7uH/1A D1 B0530 C5 2.2uF/25V L2 4.7uH/1A C4 0.47uF 25V 2 IN 8 SW MP3302 6 FB GND 1 4 EN LED+ LED- Figure 6 — Wide Input Voltage Sepic Converter for 27 WLEDs ( 3 WLEDs in Series and 9 Strings Paralleled ) MP3302 Rev. 0.94 8/2/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. www.MonolithicPower.com © 2007 MPS. All Rights Reserved. 8

资料库

MP3302(MP3302).pdf

相关推荐

人工智能-地平线

热门标签

最新资料