TPS61197 Datasheet, PDF (1/22 Pages) Texas Instruments – Single-String WLED Driver for LCD TV

TPS61197
www.ti.com
SLVSC25 – JULY 2013
Single-String WLED Driver for LCD TV
Check for Samples: TPS61197
FEATURES
1
• 8V to 30V Input Voltage
• 50 kHz to 800 kHz Programmable Switching
Frequency
• Adaptive Boost Output to White LED Voltage
• High Precision PWM Dimming Resolution up
to 5000:1
• Programmable Over-voltage Protection
Threshold at Output
• Programmable Under-voltage Threshold at
Input with Adjustable Hysteresis
• Adjustable Soft Start Time Independent of
Dimming Duty Cycle
• Built-in LED Open Protection
• Built-in Schottky Diode Open/Short Protection
• Built-in IFB Short Protection
• Thermal Shutdown
• 16L SOIC Package
APPLICATIONS
• LCD TV Backlight
DESCRIPTION
The TPS61197 provides highly integrated solutions for LCD TV backlight. This device is a current mode boost
controller driving one WLED string with multiple LEDs in series. The input voltage range for TPS61197 is from 8V
to 30V.The TPS61197 adjusts the boost controller’s output voltage automatically to provide only the minimum
voltage required by the LED string to generate the setting LED current, thereby optimizing the driver’s efficiency.
Its switching frequency is programmed by an external resistor from 50 kHz to 800 kHz.
The TPS61197 supports direct PWM brightness dimming method. During the PWM dimming, the white LED
current is turned on and off at the duty cycle and frequency which are determined by an external PWM signal.
The PWM dimming frequency ranges from 90 Hz to 22 kHz.
The TPS61197 integrates over-current protection, output short circuit protection, Schottky diode open and short
protection, LED open protection, LED string short protection and over temperature shutdown circuit. The device
also provides programmable input under-voltage lockout threshold and output over-voltage protection threshold.
The TPS61197 has a built-in linear regulator which steps down the input voltage to the VDD voltage for powering
the internal circuitry. An internal soft start circuit is implemented to work with an external capacitor to adjust the
soft startup time to minimize the in-rush current during boost converter startup. The device is available in 16-pin
SOIC package, which is ideal for a single-layer PCB board.
SIMPLIFIED SCHEMATIC CIRCUIT
VIN = 24V
L1
68uH
D1
EC1
470uF
R11
100
EC2
22uF
R1
383k
R2
24.9k
VIN
C2
2.2uF
GDRV
ISNS
UVLO
PGND
C1
10nF
TPS61197
VDD
OVP
C3
1.0uF
COMP
FSW
REF
EN
R10
3
R6
300
C5
220pF
C7
2.2uF
Q1
R5
0.1
R7
300k
R3
1.0M
C4
1nF
R4
20k
R8
50k
C6
22nF
FAULT
IDRV
Q2
PWM
R12
IFB
AGND
C8
1.0k
R9
1.0nF
1.0
Figure 1. Typical Application of TPS61197
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2013, Texas Instruments Incorporated