Microchip Technology MCP1664, User Manual

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2015 Microchip Technology Inc. DS50002363A-page 13
MCP1664 LED DRIVER
EVALUATION BOARD
USER’S GUIDE
Chapter 2. Installation and Operation
2.1 INTRODUCTION
The MCP1664 has been developed for applications that require driving a string of
LEDs from a low-voltage source. The MCP1664 is a non-synchronous step-up
regulator that can operate over a wide output range up to 32V. Its maximum output
current is based on the switch peak current limit (set to 1.8A) and on the maximum
duty cycle of 90%. An important feature is that the device integrates the compensation
and protection circuitry so that the final solution will require a minimum number of
additional components.
FIGURE 2-1: MCP1664 LED Driver Boost Converter 90,180,270 mA Constant Current Application.
2.2 FEATURES
The MCP1664 LED Driver Evaluation Board has the following features:
• Input voltage range, V
IN
: 2.4V to 5.5V, with V
IN
 V
OUT
• Undervoltage lockout: 2.3V to start; 1.85V to stop
• Adjustable output current: 90 mA, 180 mA or 270 mA, selected using a mini dip
switch on board
• PWM Switching frequency = 500 kHz
• Variable resistor and triangular wave generator on the board that can be used for
PWM dimming
• 1.8A peak current limit
• Overtemperature protection (if the die temperature e150°C, 25°C hysteresis)
• Open load protection: if the LED string fails or is disconnected, the converter will
shut down to prevent failure.
PWM Dimming
Block
( 1 )
V
IN
GND
V
FB
SW
EN
C
IN
2 x 10 µF
L
1
4.7 µH
R
10
R
11
R
12
3.3

3.3

3.3

2.4V - 5.5V
Note 1: For PWM Dimming Block refer to Figure 2-4.
D
1
MBRA140
R
3
0

Q
1
Q
2
C
OUT
10 µF
MCP1664
LED
1
LED
2
LED
3
LED
4