JAJSUP6B November 2013 – May 2024 TPS61162A , TPS61163A
PRODUCTION DATA
The PWM control interface is automatically enabled if the EasyScale interface fails to be enabled during startup. In this case, the TPS61162A, TPS61163A receives PWM dimming signals on the PWM pin to control the backlight brightness. When using PWM interface, the EN pin can be connected to VIN pin or a GPIO (refer to Section 7.2.4). If EN pin is connected to VIN pin, PWM pin alone is used to enable and disable the device: pulling PWM pin high or apply PWM signals at PWM pin to enable the device and pulling PWM pin low for more than 20ms to disable the device; if EN pin is connected to a GPIO, either pulling EN pin low for more than 2.5ms or pulling PWM pin low for more than 20ms can disable the device. Only after both EN and PWM signals are applied, the TPS61162A/TPS61163A can start up. Refer to Figure 6-4 for a graphical explanation.
When the PWM pin is constantly high, the dual channel current is regulated to full scale according to Equation 1. The PWM pin allows PWM signals to reduce this regulation current according to the PWM duty cycle; therefore, it achieves LED brightness dimming. The relationship between the PWM duty cycle and IFBx current is given by Equation 3.
where