Datasheet AP3917D (Diodes) - 9

AP3917D Performance Characteristics
(continued)
Open-Loop Detection
When the FB voltage drops below open-loop detection threshold voltage VOLD (60mV), the AP3917D stops working and begins a restart cycle. The open-loop detection is blanked for 64 switching cycles during startup process.
Overshoot Improvement
In general, there is no capacitor between FB pin and S pin. But in some cases where strict overshoot is required, we recommend a ceramic capacitor C6 (390pF to 1nF) in Figure 5.
T C U
R1 D2
D
C3
O
C2
R
C6 R2
P
L2
W
BP S VO+
E N
FB S NC Drain NC AP3917D Figure 5. Overshoot Improvement
Leading-Edge Blanking
A narrow spike on the leading edge of the current waveform can usually be observed when the power MOSFET is turned on. Normally, the leading-edge blanking time tLEB1 is built in to prevent the false-triggering caused by the turn-on spike. But in the case of short circuit, the leading- edge blanking time is tLEB2. During this period, the current limit comparator is disabled, and the gate driver cannot be switched off. AP3917D 9 of 12 June 2019 Document number: DS41540 Rev. 4 - 2
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