ZHCSNG6 November 2021 UCC28781-Q1
PRODUCTION DATA
The UCC28781-Q1 provides extensive protections on different system fault scenarios. The protection features are summarized in Table 7-3.
PROTECTION | SENSING | THRESHOLD | DELAY TO ACTION | ACTION BY UCC28781-Q1 |
---|---|---|---|---|
VDD UVLO | VDD voltage | VVDD(OFF) ≤ VVDD ≤ VVDD(ON) | None | UVLO reset |
Brown-in detection | VS current | IVSL ≤ IVSL(RUN) | 4 PWML pulses | UVLO reset |
Brown-out detection | VS current | IVSL ≤ IVSL(STOP) | tBO (60ms) plus 3 confirming PWML pulses | UVLO reset |
Over-power protection (OPP) | CS voltage | VCST(OPP) ≤ VCST ≤ VCST(MAX) | tOPP (160 ms) | tFDR restart (1.5s) |
Peak-power limit (PPL) | CS voltage | VCST ≤ VCST(MAX) | ||
Over-current protection (OCP) | CS voltage | VCS ≥ VOCP | 3 PWML pulses | tFDR restart |
Output short-circuit protection (SCP) | CS, VS, and VDD voltages | (1) VVDD = VVDD(OFF) & VCST ≥ VCST(OPP) ; (2) VVDD = VVDD(OFF) & VVS ≤ VVS(SM2) | ≤ tOPP | tFDR restart |
Output over-voltage protection (OVP) | VS voltage | VVS ≥ VOVP | 3 PWML pulses | tFDR restart |
Over-temperature protection on FLT pin (OTP) | FLT voltage | RNTC ≤ RNTCTH | tFLT(NTC) (50 µs) | UVLO reset until RNTC ≥ RNTCR |
Over-temperature protection on CS pin (OTP) | CS voltage | VCS ≥ VOCP | 2 PWMH pulses | tFDR restart |
Input over-voltage protection (IOVP) | FLT voltage | VFLT ≥ VIOVPTH | tFLT(IOVP) (750 µs) | UVLO reset until VFLT < VIOVPTH - VIOVPR |
Thermal shutdown | Junction temperature | TJ ≥ TJ(STOP) | 3 PWML pulses | UVLO reset |