HI-SINCERITY
MICROELECTRONICS CORP.
Spec. No. : HP200202
Issued Date : 1998.08.01
Revised Date : 2002.12.03
Page No. : 9/10
External Duty Cycle Clamp and Multi Unit Synchronization
Vref
RA
RB
8
8
6
5
5KΩ
+
2
C
5KΩ
1
NE555
1
To Additional
H3842
-
S
2
5KΩ
+
-
R
Q
3
7
4
+
+
-
EA
2R
5
R
4
R
BIAS
R
OSC
f=1.44/((RA+2RB)C), Dmax=RB/(RA+2RB)
Soft-Start Circuit
8
R
BIAS
R
4
+
+
2
1MΩ
C
1
5
-
EA
1mA
2R
+
R
1V
-
R
OSC
S
5Vref
+
-
Q
Soft-Start and Error Amplifier Output Duty Cycle Clamp
7
8
R
R
4
+
+
2
R2
C
R1
1
-
EA
1mA
BIAS
OSC
Vclamp
2R
R
5
BC109
1V
+
S
Q
R
Comp/Latch
+
Vcc
Vin
5Vref
+
-
7
6
Q1
5
Rs
Vclamp=R1/(R1+R2) where 0<Vclamp<1V, Ipk(max)=Vclamp/RS
H3842P
HSMC Product Specification