JAJSH85B April 2019 – April 2019 TPS566235
PRODUCTION DATA.
The TPS566235 has an internal 1.0 ms soft-start time. Soft start can prevent the overshoot of output voltage during start up. When the EN pin becomes high, internal soft-start function begins ramping up the reference voltage to the PWM comparator.
The TPS566235 can prevent current from being pulled from the output during startup if the output is pre-biased. The device disables the switching of both the high-side and low-side FETs until the soft-start commands a voltage higher than the pre-bias level (internal soft start becomes greater than feedback voltage VFB). Then, the controller start the first high side FET gate driver pulses. This scheme prevents the initial sinking of the pre-bias output, and ensure that the output voltage starts and ramps up into regulation and the control loop is given time to transition from pre-biased start-up to normal mode operation.