Boost converter for LED backlight strings
The part integrates the switching FET internally (rated 700 mA switch current) and supports PWM dimming directly on the control pin, which simplifies the BOM for portable backlight applications.
600 kHz switching — inductor and EMI planning
The fixed 600 kHz switching frequency sits in a practical band for small-footprint inductors — typically a 4.7 µH to 22 µH shielded inductor keeps ripple current manageable while staying within the 700 mA switch current ceiling. At this frequency, the fundamental switching harmonic falls below the AM broadcast band, which helps pass radiated emissions in consumer display products.
38 V output and LED string count
With a 38 V maximum output, the TPS61161DRVR can drive up to ten white LEDs in series (assuming ~3.2 V forward voltage per LED at nominal current). The actual count depends on the forward voltage drop at the programmed current and the headroom required for the current-sense resistor. The 700 mA switch current limits the total power to about 26 W at 38 V, but in practice the thermal dissipation in the 6-WSON package constrains continuous output to lower levels — derating is necessary above 70°C ambient.
Package and thermal: 6-WSON exposed pad
Without adequate thermal management, the switch current derates above 70°C ambient.