Datasheet AP3917C (Diodes) - 9
| Manufacturer | Diodes |
| Description | Universal AC High Voltage Step Down Power Switcher |
| Pages / Page | 11 / 9 — AP3917C. Operation Description. Open-Loop Detection. Overshoot … |
| File Format / Size | PDF / 603 Kb |
| Document Language | English |
AP3917C. Operation Description. Open-Loop Detection. Overshoot Improvement. T C. Leading-Edge Blanking. Ordering Information
Model Line for this Datasheet
Text Version of Document
AP3917C Operation Description
(continued)
Open-Loop Detection
When the FB voltage drops below open-loop detection threshold voltage VOLD (60mV), the AP3917C 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
R1 D2
U
C3
D
C2 C6
O
R2
R
L2
P
BP S VO+
W
FB S
E
NC
N
Drain NC AP3917C 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.
Ordering Information AP3917C X - X
Product Name Package Packing S7 : SO-7 13 : 13" Tape & Reel
Package Part Number Marking ID Packing
SO-7 AP3917CS7-13 3917C 4000/Tape & Reel
Marking Information Package Type: SO-7 (Top View)
Logo YY : Year : 19, 20, 21~ Marking ID 3917C WW : Week : 01~52; 52 represents 52 and 53 week YY WW X X X X : Internal Code
AP3917C 9 of 11 May 2019 Document number: DS41542 Rev. 2 - 2
www.diodes.com
© Diodes Incorporated
(continued)
Open-Loop Detection
When the FB voltage drops below open-loop detection threshold voltage VOLD (60mV), the AP3917C 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
R1 D2
U
C3
D
C2 C6
O
R2
R
L2
P
BP S VO+
W
FB S
E
NC
N
Drain NC AP3917C 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.
Ordering Information AP3917C X - X
Product Name Package Packing S7 : SO-7 13 : 13" Tape & Reel
Package Part Number Marking ID Packing
SO-7 AP3917CS7-13 3917C 4000/Tape & Reel
Marking Information Package Type: SO-7 (Top View)
Logo YY : Year : 19, 20, 21~ Marking ID 3917C WW : Week : 01~52; 52 represents 52 and 53 week YY WW X X X X : Internal Code
AP3917C 9 of 11 May 2019 Document number: DS41542 Rev. 2 - 2
www.diodes.com
© Diodes Incorporated
