Backlight for Small and Media Form Factor LCD Display with Single-Cell or Multi-Cell Battery Input
The TPS61176 is an integrated WLED backlight driver for tablets or notebook PCs using single-cell batteries. It comprises a high-efficiency boost converter with an integrated 2-A, 40-V power MOSFET, and six current sink regulators. The device can drive up to 60 WLEDs. The boost output voltage automatically adjusts to the WLED forward voltage to improve efficiency.
The TPS61176 supports mixed dimming mode. The automatic switch between PWM dimming and analog dimming increases the overall electrical-to-optical efficiency, reducing power of the backlight significantly. The switch point can be programmed to 12.5% or 25%. PWM dimming mode can also be programmed to fixed frequency dimming or direct PWM dimming. The device supports up to 14-bit dimming resolution to avoid potential flickering during low brightness dimming.
True shutdown is supported with a driver for an external isolation P-channel MOSFET. When the device is disabled or the boost output is shorted to ground, the isolation PFET is turned off to cut off the power path from battery preventing any leakage current from the battery. The device also integrates soft start, thermal shutdown, WLED open and short protection. Its 16-pin WQFN package provides a space-saving and high-performance WLED driver solution.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
TPS61176 | WQFN (16) | 3.00 mm × 3.00 mm |
Changes from A Revision (August 2013) to B Revision
Changes from * Revision (December 2012) to A Revision
PIN | TYPE | DESCRIPTION | |
---|---|---|---|
NAME | NUMBER | ||
COMP | 4 | Analog | Connect an external 0.47-µF ceramic capacitor to this pin for the boost loop compensation. |
GND | 8 | Ground | Analog ground |
IFB4 to IFB6, IFB1 to IFB3 |
5, 6, 7, 9, 10, 11 |
Analog | Regulated current sinks input pins |
ISET | 3 | Analog | Full-scale LED current setting pin. Connect a resistor to the pin to program the full-scale LED current. |
MODE/FAULT | 16 | Input | Multi-function pin. Use this pin to program the dimming mode. It also functions as a driver for external isolation P-channel MOSFET.(1) |
OVP | 12 | Analog | This pin monitors the output voltage of the boost converter through external resistor divider. |
PGND | 13 | Ground | Power ground |
PWM/EN | 1 | Input | PWM dimming signal input and device enable / disable control.(1) |
SW | 14 | Analog | Drain of the internal power MOSFET. |
VIN | 15 | Power | Supply input pin, provides power supply to the device. |
VLDO | 2 | Analog | Internal pre-regulator output. Connect a 1-µF ceramic capacitor to this pin. |
Thermal Pad | — | — | The GND pin should be connected to the exposed thermal pad for proper operation. This thermal pad should be connected to any internal PCB ground plan using multiple vias for good thermal performance. |