NCP1632 Datasheet, PDF (24/25 Pages) ON Semiconductor – Interleaved, 2-Phase Power Factor Controller

NCP1632
Internal
Thermal
Shutdown
TSD
Stdwn
UVP
BO_NOK
Vref
VDD
Iref
UVLO
Regul
Vcc_OK
Rt(open)
QR
Vcc
12 V / 10 V
Fault
management
OFF
30−μs
IRt_Low
S
blanking
(Ipin3 < 7 μA)
time
Figure 23. Fault Management Block
The circuit detects a fault if the R_t pin is open. Practically,
if the pin sources less than 7 mA, the “I_{Rt_Low}” signal sets
a latch that turns off the circuit if its output (R_t(open)) is high.
A 30 ms blanking time avoids parasitic fault detections. The
latch is reset when the circuit is in UVLO state (too low
V_CC levels for proper operation).
When any of the following faults is detected:
• brown−out (“BO_NOK”)
• Under−Voltage Protection (“UVP”)
• Latch−off condition (“Stdwn”)
• Die over−temperature (“TSD”)
• Too low the current sourced by the R_t pin (“R_t(open)”)
• “UVLO” (improper Vcc level for operation)
The circuit turns off. It recovers operation when the fault
disappears.
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