With a 30V-rated integrated switch FET and power diode, the TPS61158 is a boost converter that drives LEDs in series. The boost converter runs at 750-kHz fixed switching frequency to reduce output ripple, improve conversion efficiency, and allows for the use of small external components.
The default white LED current is set with the external sensor resistor RFB, and the feedback voltage is regulated to 200 mV, as shown in Typical Application. During the operation, the LED current can be controlled using the 1-wire digital interface (EasyScale protocol) through the CTRL pin. Alternatively, a pulse width modulation (PWM) signal can be applied to the CTRL pin through which the duty cycle determines the feedback reference voltage. In either digital or PWM mode, the TPS61158 does not burst the LED current; therefore, it does not generate audible noises on the output capacitor. For maximum protection, the device features integrated open LED protection that disables the TPS61158 to prevent the output voltage from exceeding the device absolute maximum voltage ratings during open LED conditions.
2.7-V to 5.5-V Input Voltage Range
28-V Open LED Protection (up to 8 LEDs)
Integrated 0.6-A, 30-V Internal Switch FET and Power Diode