9.2.1.2.3 Digital One-Wire Brightness Dimming

The CTRL pin features a simple digital interface to allow digital brightness control. The digital dimming can save the processor power and battery life as it does not require a PWM signal all the time, and the processor can enter idle mode if available.

The TPS61165 adopts the EasyScale protocol for the digital dimming, which can program the FB voltage to any of the 32 steps with single command. The step increment increases with the voltage to produce pseudo logarithmic curve for the brightness step. See Table 3 for the FB pin voltage steps. The default step is full scale when the device is first enabled (V_FB = 200 mV). The programmed reference voltage is stored in an internal register and is not changed by pulling CTRL low for 2.5 ms and then re-enabling the device by taking CTRL high. A power reset clears the register value and reset it to default.