8.1 Overview

The TPS61165 is a high-efficiency, high-output-voltage boost converter in small package size. The device is ideal for driving white LEDs in series. The serial LED connection provides even illumination by sourcing the same output current through all LEDs, eliminating the need for expensive factory calibration. The device integrates 40-V/1.2-A switch FET and operates in pulse width modulation (PWM) with 1.2-MHz fixed switching frequency. (For operation see theFunctional Block Diagram.) The duty cycle of the converter is set by the error amplifier output and the current signal applied to the PWM control comparator. The control architecture is based on traditional current-mode control; therefore, slope compensation is added to the current signal to allow stable operation for duty cycles larger than 40%. The feedback loop regulates the FB pin to a low reference voltage (200 mV typical), reducing the power dissipation in the current sense resistor.