PTC PT6908-S

PT6908
High Power LED Driver
DESCRIPTION
PT6908 is a constant-current LED driver IC utilized
constant frequency, controls buck, boost or
buck-boost switch converter. In each control mode,
PT6908 adopts the inductance current continuous
conduction, peak current control mode and the
feedback of the output current. It’s controlled by the
internal transconductance operational amplifier and
external adjustable slope compensation, it is able to
gain the high precision output current in closed loop.
The typical functions of PT6908 such as UVLO (Under
Voltage Lockout), input current limit, open LED
protection, output short circuit protection, output
current precision control, linear dimming, PWM
dimming, etc. In addition, multiple the sync pin of
PT6908s or input the same clock signal, these ICs will
operate on the same frequency.
FEATURES
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>90% Efficiency
Operating voltage: 9V~36V
Constant-current driver
Switch control mode: Buck, Boost, Buck-Boost
Stable operation frequency
Slope compensation
Output current closed loop control
Input current limit, output over voltage protection,
output short-circuit protection
• Linear dimming & PWM dimming
• Synchronization
• Soft start
Input voltage of PT6908 is 9V to 36V, the oscillator
frequency is 25KHz~350KHz that setting by the
external resistors, and the output PWM signal drive
external power NMOS. PWM dimming input can
accept an external control signal with a duty cycle
0~100% and a frequency between 100Hz to a few
KHz.
APPLICATIONS
• LED backlight
• Automotive LED lighting
• Other DC/DC LED drivers
BLOCK DIAGRAM
Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan
PT6908
TYPICAL APPLICATION
V1.3
2
February 2010
PT6908
ORDER INFORMATION
Valid Part Number
PT6908-S (L)
Package Type
16 Pins, SOP, 150mil
Top Code
PT6908-S
PIN CONFIGURATION
16 PINS, SOP
PIN DESCRIPTION
Pin Name
VIN
VDD
GATE
GND
CS
SC
RT
SYNC
CLIM
REF
FAULT
OVP
PWMD
COMP
IREF
FB
V1.3
Description
Input voltage 9V~36V DC.
Internal regulated voltage.
Drives the gate of external N-channel MOSFET.
Ground.
Senses the external MOSFET current.
Slope compensation for current sense.
Oscillator frequency control.
Synchronization control.
Input current limit & Soft start.
Reference voltage.
Drives the gate of external N-channel MOSFET. It will be locked at low level when IC
works in error condition.
Over voltage protection.
Low frequency PWM dimming pin, also enable pin.
Output of OTA, stable closed loop control.
Sets the LED string current level.
LED string current feedback & output short circuit protection.
3
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
February 2010
PT6908
IMPORTANT NOTICE
Princeton Technology Corporation (PTC) reserves the right to make corrections, modifications, enhancements,
improvements, and other changes to its products and to discontinue any product without notice at any time.
PTC cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a PTC product. No
circuit patent licenses are implied.
Princeton Technology Corp.
2F, 233-1, Baociao Road,
Sindian, Taipei 23145, Taiwan
Tel: 886-2-66296288
Fax: 886-2-29174598
http://www.princeton.com.tw
V1.3
4
February 2010