Six-channel boost for LCD backlight strings
The TPS61180RTERG4 is a six-channel DC-DC boost regulator from Texas Instruments, purpose-built for driving LED backlight arrays in medium-sized LCD panels. Each of the six outputs sinks a regulated 25 mA, and the boost converter delivers up to 38 V on the output rail — enough headroom to stack eight to ten white LEDs in series per channel, depending on their forward voltage at full current. Switching at 1 MHz, the part works with a small inductor and ceramic input/output capacitors, keeping the total power-stage footprint compact. PWM dimming is handled directly on the enable pin, so the host processor can vary brightness without an external PWM generator.
Output voltage and channel current — sizing the LED load
The 38 V output ceiling sets the maximum series LED count per channel. With a typical white LED forward voltage of 3.0–3.4 V at 25 mA, eight LEDs in series require roughly 27 V of compliance, leaving margin for the current-sink headroom and line regulation. Six channels at 25 mA each give a total backlight power budget around 5.7 W at 38 V — the designer should derate for ambient temperature and inductor saturation current. The boost topology means the input voltage range of 5 V to 24 V covers common rails from USB power to automotive battery-derived supplies. At minimum input, the duty cycle climbs, so the inductor ripple current and output ripple deserve a close look during the layout review.