LP8863-Q1: LP8863-Q1 start up and shutdown sequence

Hi Nagasawa-san,

Please don't worry about your questions. One thing is that email will be more efficient to handle many questions due to the limitation of editing on web browser.

(1)What is the transition trigger from Device INIT state to STAND BY state ?

A) There is no separate trigger for this state change, but it takes a few hundred us to finish INIT state for internal setup.

(2)How long is the time (max) from triggering to transition?(raugh time is helpful for us,not need gurantee)

A) As shown above, it takes a few hundred us for the transition. I would say max 500us.

(3)How long is the minimum time (or PWM cycle number?) required from the start of PWM input until EN High in start up sequence?

A) There is no requirement for PWM timing. LED driver will be enabled ~100ms after EN input, so there are plenty of time to input PWM signal. If you want to turn on LEDs fast enough, PWM input should be inputted before boost start, so LED driver can be enabled at correct brightness right after boost start

(4)How long is the minimum time (PWM cyc number?) required to stop PWM input from EN Lo in shutdown sequence?

A) There is no requirement for PWM stop timing. You can stop and start PWM signal any time during normal operation. If you stop PWM before EN low, brightness change to off state will be affected by slope time. If you make EN low while PWM is enabled, LEDs will turn off immediately

(5)About shutdown sequence, please tell me the behavior if not maintain 400 ms of DISCHARGE period and power-off.

A) 400ms is just max possible discharge time of boost, not a setting time. DISCHARGE function is designed to lower boost out voltage fast during shutdown to avoid any side effect by high voltage such as leakage through LEDs or over stress on each boost component while device is disabled. This DISCHARGE time can vary with boost out voltage and Cout values.

Hope this helps,