MP3302DD-LF-P

1. DESCRIPTION

The MP3302DJ-LF-ZX is a step-up converter designed for driving arrays of WLEDS from a single cell Lithium Ion battery. The MP3302DJ-LF-ZX uses current mode, fixed frequency architecture to regulate the LED current, which is measured through an external current sense resistor. Its low 200mV feedback voltage reduces power loss and improves efficiency. The MP3302DJ-LF-ZX is turned off if an over-voltage condition is present due to an open circuit condition.

The MP3302DJ-LF-ZX includes under-voltage lockout, current limiting and thermal overload protection preventing damage in the event of an output overload. The MP3302DJ-LF-ZX is available in small 5-pin TSOT23 and 8-pin QFN (2mm x 3mm) packages.

2. FEATURES

    1. Internal Power MOSFET

    2. Drives up to 10 Series White LEDs

    3. Up to 87% Efficiency

    4. Single Wire Dimming Control

    5. 1.3MHz Fixed Switching Frequency

    6. Open Load Shutdown

    7. Low 200mV Feedback Voltage

    8. UVLO, Thermal Shutdown

    9. Internal 1.3A Current Limit

  10. Available in TSOT23-5 and 2mm x 3mm QFN8 Packages 

3. APPLICATIONS

    1. 5”~ 7” LCD Panels

    2. Handheld Computers and PDAs

    3. Digital Still Cameras

    4. Small LCD Displays 

4. Operation method

MP3302DD-LF-Z uses constant frequency peak Current mode boost regulator architecture Adjust the series string of white LEDs. of Understand the operation of MP3302DD-LF-Z. At the beginning of each oscillator cycle, the FET is Turn on through the control circuit. to Prevent sub-harmonic oscillation in duty cycle More than 50%, the stable slope is Added to the current sensed output Amplifier, the result is fed into a positive number Input to the PWM comparator. When this The voltage is equal to the error output voltage The amplifier, the power FET is turned off. 

Error amplifier output voltage Is an enlarged version of the difference At 200mV reference voltage and Feedback voltage. Peak current The level keeps the output stable. If the feedback voltage starts to drop, the output The power of the error amplifier increases. Which resulted in More current flows through the power FET, Thereby increasing the delivery to Output.

5. LED current programming

Apply a DC voltage between 0.7V and 1.4V To EN pin programming feedback voltage Between 0V and 200mV. Therefore, the simulation The dimming of the LED current can be realized. of DC dimming voltage must be bypassed locally Prevent noise from interfering with feedback.

6. PWM dimming

Apply 200Hz to 1kHz square wave to EN pin realizes PWM dimming led. Minimum recommended amplitude 1.5V for PWM signal. For high frequency PWM dimming (> 1kHz), it is also recommended to implement dimming control. The frequency of the RC filter should be 10 times lower than the input PWM signal. for For example, when the PWM frequency is 20kHz, 20kΩ resistors and 100nF capacitors can be used. Then, the DC voltage on the EN pin is equal to PWM high level voltage multiplied by PWM obligation. DC voltage from 0.7V to 1.4V Set the output current between 0~100%.

7. TYPICAL APPLICATION

8. PACKAGE REFERENCE

9. PACKAGE INFORMATION