1 Features
1• 2.5-V to 24-V Input Voltage Range
• 39-V Maximum Output Voltage
• Integrated 1.8-A, 40-V MOSFET
• 450-kHz to 1.2-MHz Programmable Switching
Frequency
• Adaptive Boost Output to WLED Voltages
• 100-Hz to 25-kHz Wide Input PWM Dimming
Frequency Range
• 1% Minimum Dimming Duty Cycle
• Small External Components
• Integrated Loop Compensation
• Six Current Sinks of 30 mA Maximum
• 1% (Typical) Current Matching
• Input PWM Glitch Filter
• PWM Brightness Interface Control
• Three Optional Dimming Methods, including Direct
PWM Dimming, Analog Dimming, and Analog and
PWM Mixed Dimming
• Built-in WLED Open Protection
• Thermal Shutdown

2 Applications
• Notebook and Tablet LCD Display Backlights
• Patient Monitors
• Medical Displays
• HMI
• Test and Measurement Equipment

3 Description
The TPS61177A device provides a highly integrated
white LED (WLED) driver solution for notebook LCD
backlight. This device has a built-in high-efficiency
boost regulator with integrated 1.8-A, 40-V power
MOSFET. The six current sink regulators provide high
precision current regulation and matching. In total, the
device can support up to 72 WLEDs. In addition, the
boost output automatically adjusts its voltage to the
WLED forward voltage to optimize efficiency.
The TPS61177A supports the analog dimming,
analog and PWM dimming, and direct PWM dimming
method. During analog dimming mode, each CS
current linearly varies depending on the duty cycle
information on the PWMB pin. During analog and
PWM mixed dimming mode, the input PWM duty
cycle information is translated to an analog signal to
control the WLED current linearly over 25% to 100%
brightness area. The device also allows adding PWM
dimming when the analog current is down to 25%.
Below 25%, the analog signal translates to PWM duty
cycle information to control the on or off of WLED
current and averages the WLED current down to 1%.
The frequency of adding PWM dimming is same to
input PWM frequency on the PWMB pin. While the
TPS61177A also supports a direct PWM dimming
method, in direct PWM dimming mode the WLED
current is turned on or off, synchronized with the input
PWM signal.