JAJSJM2B July 2022 – April 2024 TPS929240-Q1
PRODUCTION DATA
Because the TPS929240-Q1 supports PWM control for adjusting LED brightness, the voltage on OUTXn is like a pulse waveform. When the current output is enabled by setting ENOUTXn to 1, the ADC measures the voltage on assigned OUTXn after the output is turned on with t(BLANK) delay time, which is programmable by 4-bit register BLANK. The minimum current output pulse on assigned OUTXn must be longer than t(BLANK) + 3 × t(CONV) to make sure the correct measured result for OUTXn at ON state. When the output is disabled by setting ENOUTXn to 0, the ADC samples the voltage on assigned OUTXn at OFF state.
TI recommends to set 100% duty cycle on assigned OUTXn for ADC measurement by writing FFh to PWMOUTXn and 0Fh to PWMLOWOUTXn register when the PWM dimming period t(DIM_cycle) has to be less than t(BLANK) + 3 × t(CONV).