PS25A Datasheet, PDF (8/11 Pages) Silicon Touch Technology Inc. – Over/Under-voltage protection and lock out

Application
Typical 3 rails SPS
PS25A
S.P.S. Secondary Side
+12VA Coil
+12VB Coil
+12VC Coil
RS12 A
RS12 B
RS12 C
+12VA Output
+12VB Output
+12VC Output
VDET
2K
+12V SB
PSON
1 PGI
PGO 14
2 GND
3 FPO/
4 PSON/
5 RI
Vcc 13
VS12C 12
IS12C ₁₁
VS12A 10
6 IS12B IS12A 9
7 VS12 B PEXT 8
PGO
+12VSB
Pext
Notes:
1. Zener diode or resistor or both of them can be used in component X.
2. The bypass capacitor C_by suggests to be 0.1uF~ 10uF and layout nearby pin VCC.
3. The recommend sense values of R_S12A, R_S12B are ≥ 0.002Ω.
4. Over-Current Protection design example:
(1)
I _ref
=
20μA , R_I
= ^VRI
I _RI
= ^1.25 = 62.5K (Ω)
20μ
(2) R_S5=0.002 Ω , ΔV_5V = 0.002 × I_+5V = R_OC5 × 8 × I_ref
(3)
If 12V OCP trip point is 20A,
R_{OC 5}
=
0.002 × 20
8 × 20μ
=
250(Ω)
3-Channel Secondary Monitoring IC Version：A.005
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