9 / 14 page
PJ3842B / PJ3843B
High Performance Current Mode Controller
9-14
2004/11.Rev B
FIGURE 20-EXTERNAL CLOCK
SYNCHRONIZATION
FIGURE 21-EXTERNAL DUTY CYCLE CLAMP AND
MULTI UNIT SYNCHRONIZATION
The diode clamp is required if the Sync amplitude is large enough
to the cause the bottom side of CT to go more than 300mV below
ground.
()
B
A
R
R
1.44
f
+
=
B
A
B
MAX
2R
R
R
D
+
=
FIGURE 22-ADJUSTABLE REDUCTION OF CLAMP
LEVEL
FIGURE 23-SOFT-START CIRCUIT
1.0V
Vclmap
：
Where
Rs
Vclmap
(max)
I
pk
≤
≤
=
+
×
+
+
=
−
R2
R1
R2
R1
10
0.33
1
R1
R2
1.67
Vclamp
3
Isoft-Start=3600c in µF
FIGURE 24-ADJUSTABLE BUFFERED REDUCTION
OF CLAMP LEVEL WITH SOFT-STAR
FIGURE 25-CURRENT SENSING POWER MOSFET
Virtually lossless current sensing can be achieved with the
implementation of a SENSEFET power switch.For proper operation
during over current conditions.a reduction of the Ipk(max) clamp level
must be implemented.Refer to Figure 22 and 24
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
