MP3302
1.3A Fixed Frequency
White LED Driver
The Future of Analog IC Technology
DESCRIPTION
The MP3302 is a step-up converter designed for driving up to 27 white LEDs, 3 WLEDs in ries 9 strings, all from a single cell Lithium Ion battery. The MP3302 us current mode, fixed frequency architecture to regulate the LED current, which is measured through an external current n resistor. Its low 195mV feedback voltage reduces power loss and improves efficiency. The MP3302 is turned off if an over-voltage condition is prent 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. FEATURES
• Internal Power MOSFET
• 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.
TYPICAL APPLICATION
V
E F F I C I E N C Y (%)
3
456INPUT VOLTAGE(V)
Efficiency vs Input Voltage
PACKAGE REFERENCE
* For Tape & Reel, add suffix –Z (eg. MP3302DJ–Z)
肯定英文For RoHS Compliant Packaging, add suffix –LF
(eg. MP3302DJ–LF–Z)
ABSOLUTE MAXIMUM RATINGS (1) –0.5V to +40V All .–0.3V to +6.5V –55°C to +150°C Recommende
d Operating Conditions (2) IN .2.5V to 6V V IN to 36V –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)θJA θJC
<.110..°C/W QFN8 (2mm x 3mm)...............80......16...°C/W Notes:
1) Exceeding the 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
V IN = V EN = 5V, T A = +25°C, unless otherwi noted.
Parameters Symbol
Condition Min
Typ
Max Units Operating Input Voltage V IN 2.5 6 V Supply Current (Shutdown) V EN = 0V 4 8 µA Supply Current (Quiescent) V FB = 0.15V 690 850µA Switching Frequency f SW 1.0 1.3 1.5
yfjMHz Maximum Duty Cycle V FB = 0V 92 %
last christmas taylor swiftUnder Voltage Lockout
IN Under Voltage Lockout UVLO V IN Rising 2.25 2.45V
Under Voltage Lockout
Hysteresis
92 mV
Open Lamp Shutdown
Threshold
V OV V OV Rising 38 V
ELECTRICAL CHARACTERISTICS (continued)
V IN = V EN = 5V, T A = +25°C, unless otherwi noted.
Parameters Symbol Condition Min Typ Max Units Enable
EN OFF Threshold V EN Falling 0.4 V EN ON Threshold V EN Rising 0.6 V Minimum EN Dimming
Threshold
V FB = 0V
0.7 V Maximum EN Dimming
Threshold V FB = 0.2V
1.4 V Feedback FB Voltage V EN = 1.5V 195 mV FB Input Bias Current V FB = 0.1V -600
-300
nA
Output Switch
SW On-Resistance (4) R ON 0.5 Ω SW Current Limit (4) Duty Cycle = 60% 1.33 A Thermal Shutdown (4)
150 °C
blogerNotes:
4) Guaranteed by design.
PIN FUNCTIONS
TSOT23-5 Pin # QFN8
Pin #
Name Pin Function
1 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.
2 1, 5 GND Ground.
3 6 FB
Feedback Input. The MP3302 regulates the voltage across the current n resistor between FB and GND. Connect a current n resistor from the bottom
of the LED string to GND. Connect the bottom of the LED string to FB. The regulation voltage is 195mV.
4 4 EN 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, V FB is regulated between 0V and 195mV. To u PWM
dimming, apply a 200Hz to 1KHz square wave signal with amplitude greater than 1.5V to this pin.
5 2 IN Input Supply Pin. Must be locally bypasd. 3 NC No Connect.
TYPICAL PERFORMANCE CHARACTERISTICS
V IN = 5V, 3WLEDs 9Strings, unless otherwi noted.
V SW 10V/div.V EN 2V/div.V OUT 5V/div.
V EN 2V/div.V EN 5V/div.connecticut
V OUT 5V/div.
I LED
100mA/div.
Enable Startup
V SW 10V/div.I LED
100mA/div.
V EN 5V/div.V OUT 5V/div.
V SW 10V/div.
comodo是什么意思
I LED
100mA/div.
Enable Shutdown
PWM Dimming
V SW 20V/div.V OUT 20V/div.
Start Up into Openload
V SW 10V/div.
V FB
50mV/div.
V OUT
AC Coupled 100mV/div.I inductor 500mA/div.
我很好英语400ns/div.
Steady State Operation
V IN = 5V, 3 WLEDs,9 Strings
V IN = 5V, 3 WLEDs,9 Strings
大街网招聘信息V IN = 5V, 3 WLEDs,9 Strings
V IN = 5V
V IN = 5V, 3 WLEDs,9 Strings
f=1kHz
V IN =5V, 3 WLEDs, 9 Strings
V IN =5V, 3 WLEDs, 9 Strings 0
0.20.40.81
PWM DIMMING DUTY
Output Current vs PWM Dimming Duty
O U T P U T C U R R E N T (m A )
EN PIN VOLTAGE (V)
Output Current vs
Analog Dimming Voltage
E F F I C I E N C Y (%)
3
6065707580859095456INPUT VOLTAGE(V)
Efficiency vs Input Voltage
OPERATION
The MP3302 us a constant frequency, peak current mode boost regulator architecture to regulate the ries 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 n 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.
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 increas. This results in more current flowing through the power FET, thus increasing the power delivered to the output.
SW
GND
-+
FB ENpama
Figure 1—Functional Block Diagramshrink是什么意思
