8-channel boost LED backlight controller — external MOSFET required
The Texas Instruments TPS61199PWPR is an 8-channel DC DC boost controller designed for LCD backlight applications. It drives up to eight LED strings at 70 mA per channel, using an external MOSFET switch per the step-up topology. PWM dimming input provides the wide contrast ratio needed in monitor, TV, and automotive display backlights. The switching frequency range of 500 kHz to 800 kHz allows the designer to trade inductor size against switching losses. Operating from an 8 V to 30 V supply, it covers standard 12 V and 24 V backlight rails.
500–800 kHz switching — inductor and EMI planning
The 500 kHz to 800 kHz switching range is a design variable: a lower frequency reduces switching loss but requires a larger inductor; a higher frequency shrinks the magnetics but increases gate-drive loss and may push EMI beyond the CISPR 22 limit without careful layout. Plan the LC filter and snubber around the selected frequency.
8 outputs at 70 mA — external switch BOM impact
Each of the eight channels requires an external N-channel MOSFET and a current-sense resistor. The controller itself does not contain internal switches — the BOM adds eight FETs, eight sense resistors, and one boost inductor plus output capacitors. Budget board area accordingly.