Texas Instruments TPS61196

Description

The TPS61196 provides a highly integrated solution for LCD TV backlight with an independent PWM dimming function for each string. This device is acurrent mode boost controller driving up to six WLED strings with multiple LEDs in series. Each string has an independent current regulator providing a LED current adjustable from 50mA to 400mA within ±1.5% matching accuracy. The minimal voltage at the current sink is programmable in the range of 0.3V to 1.0V to fit with different LED current settings. The input voltage range for TPS61196 is from 8V to 30V.The TPS61196 adjusts the boost controller's output voltage automatically to provide only the voltage required by the LED string with the largest forwardvoltage drop plus the minimum required voltage at that string's IFB pin, thereby optimizing the driver's efficiency. Its switching frequency is programmed by an external resistor from 100kHz to 800kHz.The TPS61196 supports direct PWM brightness dimming. Each string has an independent PWM control input. During the PWM dimming, the LEDcurrent is turned on/off at the frequency and duty cycle which are determined by the external PWM signal. The PWM frequency ranges from 90Hz to 22kHz.The TPS61196 integrates over current protection, output short circuit protection, ISET short to ground protection, diode open and short protection, LED open and short protection, and over temperature shutdown circuit. In addition, the TPS61196 can detect the IFB pin short to ground to protect the LED string. The device also provides programmable input under-voltage lockout threshold and output over- voltage protection threshold.The TPS61196 has a built-in linear regulator which steps down the input voltage to the VDD voltage for powering the internal circuitry. An soft start circuit is implemented internally to work with an external capacitor to adjust the soft startup time to minimizev the in-rush current during boost converter startup. The device is available in 28-pin HTSSOP package with powerPAD

Features

• 8V to 30V Input Voltage
• Up to 120V Output Voltage
• 100KHz to 800kHz Programmable Switching Frequency
• Adaptive Boost Output for LED Voltages
• Six Current Sinks, 200mA Continuous Output 400mA Pulse Output for Each String
• ±1.5% Current Matching Between Strings
• High Precision PWM Dimming Resolution up to 5000:1
• Programmable Over-voltage Threshold at Output and Each Current Sink
• Programmable Under-voltage Threshold at Input with Adjustable Hysteresis
• Adjustable Soft Start Time Independent of Dimming Duty Cycle
• Built-in LED Open/Short Protection
• Built-in Schottky Diode Open/Short Protection
• Built-in ISET Short Protection
• Built-in IFB Short Protection
• Thermal Shutdown

Remark:

The TPS61196 is designed to work with inductor values between 10 μH and 100 μH, depending on the switching frequency

Typical applications

• Scan Mode LCD TV Backlight
• LCD TV Backlight

More information

• Datasheet
• IC product information