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PT16972
4-Channel 100mA LED Driver
with DC-DC Controller
DESCRIPTION
PT16972 is a 4-Channel constant current LED driver
with current-mode switching DC-DC controller. The
output current range can be externally programmed for
10mA~100mA per channel. Also, the output voltage
can be up to 36V. The PT16972 supports the boost,
coupled-inductor boost-buck or SEPIC topologies and
operates in an adjustable switching frequency between
200kHz and 2.1MHz.
High PWM dimming ratio 2500:1 can be achieved by
internal fast response time 2μS with 200Hz PWM
dimming frequency.
The PT16972 allows to detect and manage the open
and shorted LED faults and to let unused channel
floating. Also, the device includes output over-voltage
protection, thermal shutdown protection and internal
power MOSFET over-current protection. Two fault
indication pins are provided to separate the failure
mode.
FEATURES
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6V~36V Input Voltage
Output Voltage Up to 36V
Output Current Range 10mA~100mA/CH
±1% LED Current Matching at 20mA or Higher
Programmable Frequency 200KHz~2.1MHz
2uS Minimum PWM Dimming on Time
Support Boost, Coupled-Inductor Boost-Buck or
SEPIC Topologies
Selectable Output Channels
Low Standby Current
Adjustable Internal MOSFET Current Limitation
and Soft-Start
LED Open / Short Protection
Output Over-Voltage Protection
Thermal Shutdown Protection at 150℃
Two Fault Indication Pins
TSSOP24 (173mil) with Exposed PAD Package
APPLICATIONS
• Automotive Navigation LCD Panel Backlight
• Desktop and Notebook LCD Panel Backlight
• PDAs Panel Backlight
BLOCK DIAGRAM
Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan
PT16972
TYPICAL APPLICATION
Boost Configuration
SEPIC Configuration
V1.0
2
October 2011
PT16972
ORDER INFORMATION
Valid Part Number
PT16972
Package Type
HTSSOP24
Top Code
PT16972-HT
PIN CONFIGURATION
V1.0
3
October 2011
PT16972
PIN DESCRIPTION
Pin Name
LED1
LED2
LED3
LED4
/FLT1
/FLT2
SET
ISET
/EN
VDD
NC
VIN
PWM
AGND
RT
COMP
SC
ILIM
SST
OVP
PGND
PGND
SW
SW
V1.0
Description
LED String Driver Output 1.
LED String Driver Output 2.
LED String Driver Output 3.
LED String Driver Output 4.
Fault Signal Open Drain Output. /FLT1 will be low when LED open or shorted is detected.
Fault Signal Open Drain Output. /FLT2 will be low when thermal shutdown or output over-voltage
is detected.
Channel Selection. Pin logic level will set the output channels: SET=0 or floating, 4 channels are
used; SET=1, LED4 is not used. An internal 100kΩ pull-low resistor is used.
LED Current Setting. A resistor to AGND to program the output current per channel.
Enable Control. /EN=0 or floating, the device is turn on. /EN=1, the device is turned off. An
internal 100KΩ pull-low resistor is used.
Internal 5V Regulator Output. Bypass to AGND with a 10μF ceramic capacitor.
Non-Connection.
Input Supply Voltage.
External PWM Dimming Input. PWM=0 or floating, the switching and the current generators are
turned off. PWM=1, the switching and the current generators operate normally. An internal
100KΩ pull-low resistor is used.
Analog Ground.
Switching Frequency Setting. A resistor to AGND which programs the switching frequency
between 200KHz and 2.1MHz.
Error Amplifier Output pin. Tie the external compensation network.
Slope Compensation Setting. A resistor between this pin and AGND is needed. It can avoid
sub-harmonic instability.
Internal Switch Current Limit Setting. A resistor to AGND to program the current limit level of
power MOSFET.
Soft-Start. Connect a capacitor to AGND to set the soft-start time.
Over Voltage Protection. When VOVP>1.2V, the over-voltage protection occurs.
Power Ground. Source of internal power MOSFET.
Power Ground. Source of internal power MOSFET.
Switching pin. Drain of internal power MOSFET.
Switching pin. Drain of internal power MOSFET.
4
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
October 2011
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