MC34152, MC33152, NCV33152
I
B
+
V
in
0
−
Base
Charge
Removal
C
1
V
in
R
g(on)
100k
R
g(off)
In noise sensitive applications, both conducted and radiated EMI can
be reduced significantly by controlling the MOSFET’s turn−on and
turn−off times.
The totem−pole outputs can furnish negative base current for
enhanced transistor turn−off, with the addition of capacitor C
1
.
Figure 23. Controlled MOSFET Drive
V
CC
= 15V
47
+
0.1
6
+
−
5.7V
2
100k
7
Figure 24. Bipolar Transistor Drive
+
6.8
10
+
100k
1N5819
+ V
O
≈
2 .0V
CC
+
47
5
100k
6.8
10
+
1N5819
47
V
CC
10k
2N3904
100k
330
pF
4
− V
O
≈
−V
CC
+
3
Output Load Regulation
The capacitor’s equivalent series resistance limits the Drive Output Current to 1.5 A. An
additional series resistor may be required when using tantalum or other low ESR capacitors.
I
O
(mA)
0
1.0
10
20
30
50
+V
O
(V)
27.7
27.4
26.4
25.5
24.6
22.6
−V
O
(V)
−13.3
−12.9
−11.9
−11.2
−10.5
−9.4
Figure 25. Dual Charge Pump Converter
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