Diodes PAM2845 User Manual
Pam2845, Description, Features
PAM2845
Document number: DSxxxxx Rev. 1 - 2
1 of 14
www.diodes.com
October 2012
© Diodes Incorporated
PAM2845
A Product Line of
Diodes Incorporated
40V HIGH POWER BOOST CONVERTER with
6 CHANNEL CONSTANT CURRENT SOURCE
Description
The PAM2845 is a high-efficiency boost type LED driver. It is
designed for large LCD panel that employs an array of LEDs as back
light source.
The PAM2845 employs a current-mode step-up converter that drives
six parallel strings of LEDs connected in multiple series. This built-in
string current-control circuit achieves ±1% typical current matching
between strings, which ensures even brightness for all LEDs.
Separate feedback loops limit the output voltage if one or more LEDs
open or short. The PAM2845 has features cycle-by-cycle current limit
to provide consistent operation and soft-start capability. A thermal-
shutdown circuit provides another level of protection.
The PAM2845 has a wide +4.8V to +28V input voltage range and
provides adjustable full-scale LED current. The switching frequency of
this device can be selected among 500kHz, 1MHz and 1.6MHz
according to the application requirements.
Features
•
Six Constant-Current Output Channels
•
Parallel Channels Allow Higher Current per LED String
•
Maximum 40V Continuous Voltage Output Limit for Each
Channel
•
Adjustable Constant Output Voltage
•
Adjustable Constant LED Current
•
Drives 10 or more LEDs Each String as Long as the String
Voltage Less Than 40V
•
Internal 2.5A Power MOSFET
•
Allows Digital PWM and Analog Dimming
•
Wide (100:1) PWM Dimming Range without Color Shift
•
Independent Dimming and Shutdown Control of the LED Driver
•
±1% Typical Current Matching between Strings
•
Short LED Protection
•
3 Frequencies Selection: 1.6MHz/1MHz/500kHz
•
Wide Input Voltage Range: 4.8V to 28V
•
Over Temperature Protection
•
Available in 24-pin 4mmx4mm QFN Package
•
Pb-free Package
Pin Assignments
Applications
•
White or RGB Backlighting for LCD, TV, LCD Monitor, Notebook,
Handy Terminals, and Avionics Displays Panels
•
LED Lighting Devices