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CONSONANCE |
Switch-Mode High-Brightness LED Driver
CN5610
General Description:
The CN5610 is a PFM high efficiency LED driver
control IC. It allows efficient operation of high
brightness LED from input voltage ranging from 3V
to 450V. The CN5610 controls an external N
channel MOSFET or NPN transistor at the frequency
up to 300KHz. The LED string is driven at constant
current rather than constant voltage, thus providing
constant light output and enhanced reliability. The
output current can be programmed from 30mA to
1.2A with an external resistor. The other features
include soft start circuit, inductor current limit circuit,
etc.
The CN5610 is available in a 8-pin SOP package.
Applications:
z LED Lighting
z DC-DC or AC-DC LED Driver Application
z Back Lighting of Flat Panel Displays
z RGB Back Lighting LED Driver
Features:
z Operating Supply Voltage Range: 3V to 6V
z Programmable Inductor Current Limit Level
z Soft Start Circuit
z Driving up to hundreds of LEDs
z Adjustable Output Current up to 1.2A
z Operating Temperature Range:
40 to 85
z Available in 8-pin SOP Packages
z Pb-free
Pin Assignment
VDD 1
GND 2
CL 3
NC 4
8 CS
CN5610
7 DRV
6 CLSET
5 NC
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Typical Application Circuit
Input Supply Voltage 6V to 450V
R6
R3
R1
Q1
C1
R4
Q2
L1
LED
R2
LED string
LED
D2
D1 C2
R5 1
VDD
67
CLSET
DRV
CN5610
8 CS
CL 3
GND
2
M1
NMOSFET
C3
Figure 1 Typical Application Circuit
In Figure 1,
z L1 is the inductor, generally the inductance may be around 1mH.
z D1 is zener diode whose breakdown voltage is around 6V
z D2 is rectifier diode, shottky diode is better for higher efficiency
z Q1 and Q2 are PNP transistors, many part number such as A94 can be used
z M1 is N channel MOSFET, for 400V voltage rating, IRF840 or IRF740 can be used
z R2 should be chosen so that Q2’s collector current is about 100uA
z R4 should be chosen so that Q1’s collector current is as close as possible to Q2’s collector current
Q1’s collector current 1.22/R4
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