ZHCSN24A August 2019 – May 2021 TPS53676
PRODUCTION DATA
The TON_MAX_FAULT_LIMIT command sets a maximum allowable time during which the output voltage must reach the regulation window during turn-on. The TON_MAX time is defined as the time between the first switching pulses, and the sensed output voltage exceeding the the minimum allowed regulation point, defined as VTONMAX, in the equation below. Program the TON_MAX_FAULT_LIMIT greater than the TON_RISE.
The figure below illustrates the TON_MAX fault. TPS53676 enables its undervoltage fault protection at the first PWM pulses, during the output voltage rise time. Consequently, whenever the VOUT_UV_FAULT_RESPONSE is not set to the ignore response, it triggers first and disables power conversion prior to the TON_MAX time.
In response to the TON_MAX fault condition, TPS53676 responds according to the programmed TON_MAX_FAULT_RESPONSE. When not set to the ignore response, this causes the PWM pins of the rail which experienced the fault to tristate immediately. The TPS53676 then sets the appropriate status bits in STATUS_WORD and STATUS_VOUT and asserts the SMB_ALERT# line if these bits are not masked.