NCP1200 ON Semiconductor, NCP1200 Datasheet - Page 13

• Manufacturer Part Number: NCP1200
• Description: Current Mode Controller Fixed Frequency Operation
• Manufacturer: ON Semiconductor

Improving the Output Drive Capability
to soften the EMI signature. Figure 25 depicts the way the
driver is internally made:
capability by adding either one or two bipolar transistors.
Figures 26, 27, and 28 give solutions whether you need to
improve the turn-on time only, the turn-off time or both. Rd
is there to damp any overshoot resulting from long copper
traces. It can be omitted with short connections. Results
showed a rise fall time improvement by 5X with standard
2N2222/2N2907:
The NCP1200 features an asymmetrical output stage used
In some cases, it is possible to expand the output drive
Figure 25. The higher ON resistor slows down
the MOSFET while the lower OFF resistor
ensures fast turn-off.
Q\
Q
2
3
40
12
V
CC
7
1
5
http://onsemi.com
NCP1200
13
1
2
3
4
1
2
3
4
Figure 27. Improving Turn-Off Time Only
Figure 28. Improving Turn-On Time Only
NCP1200
Figure 26. Improving Both Turn-On and
1
2
3
4
NCP1200
NCP1200
8
7
6
5
8
7
6
5
Turn-Off Times
8
7
6
5
Rd
1N4148
1N4148
2N2222
2N2907
2N2222
2N2907
To Gate
To Gate
To Gate