Boost LED driver for multi-string backlights
The LP8545SQE/NOPB is a DC-DC boost regulator from Texas Instruments, purpose-built for backlight applications. It integrates six regulated current sinks, each rated for 50 mA, and a built-in switching FET for the boost stage. The boost topology steps the input voltage up to a 40 V maximum output rail, which feeds the LED strings. PWM dimming is handled on-chip, so the host controller sends a duty-cycle signal rather than switching the output rail directly.
Switching frequency options shape the inductor and board
The LP8545SQE/NOPB offers four selectable switching frequencies: 156 kHz, 312 kHz, 625 kHz, and 1.25 MHz. A lower frequency reduces switching losses but demands a larger inductor; 1.25 MHz shrinks the magnetics but increases FET switching loss and EMI filtering effort. The input supply range spans 2.7 V to 22 V, so it works off a single lithium-ion cell, a 5 V USB rail, or a 12 V backlight supply. The 40 V output ceiling supports up to ten series LEDs per string, depending on the forward voltage of the chosen part.
Package and thermal considerations for the layout
The operating temperature range is -30°C to 85°C ambient, covering most indoor and automotive-cabin backlight applications. Surface-mount assembly with a WQFN package means the board house needs a stencil aperture matched to the 0.5 mm pitch pads.
Active lifecycle and compliance baseline
The part is RoHS3 compliant. No REACH or UL documentation is carried in the available records, so confirm with the TI datasheet if those certifications are required for your end-equipment compliance file.