NCP1396B ON Semiconductor, NCP1396B Datasheet - Page 16

• Manufacturer Part Number: NCP1396B
• Description: High Performance Resonant Mode Controller featuring High-voltage Drivers
• Manufacturer: ON Semiconductor

The selection of the three setting resistors (Fmax, Fmin
deadtime) requires the usage of the selection charts
displayed below:
selection depending on the adopted minimum switching
650
550
450
350
250
150
2000
1900
1800
1700
1600
1500
1400
1300
1200
1100
1000
420
370
320
270
220
170
120
50
900
800
700
600
500
400
300
200
100
Figure 35. Maximum switching frequency resistor
70
20
Figure 36. Minimum switching frequency resistor
1.5
2
3.5 8.5 13.5 18.5 23.5 28.5 33.5 38.5 43.5 48.5 53.5 58.5 63.5 68.5 73.5 78.5 83.5
Figure 37. Dead-Time Resistor Selection
4
3.5
6
8
5.5
10
7.5
12
frequency
selection
14
RFmax (kΩ)
RFmin (kΩ)
9.5
Rdt (kΩ)
16
11.5
18
20
13.5
22
24
15.5
NCP1396A, NCP1396B
Fmin = 200 kHz
Fmin = 50
26
Vcc = 12 V
FB = 6.5 V
DT = 300 ns
Vcc = 12 V
FB = 1 V
DT = 300 ns
Vcc = 12V
17.5
28
http://onsemi.com
30
16
ORing capability
frequency variation linked to an event appearance (instead
of abruptly stopping pulses), then the FB pin lends itself
very well to the addition of other sweeping loops. Several
diodes can easily be used perform the job in case of
reaction to a fault event or to regulate on the output
current (CC operation). Figure 38 shows how to do it.
Dead-time control
the half-bridge configuration comes to play. The dead-
time technique consists in inserting a period during which
both high and low side switches are off. Of course, the
dead-time amount differs depending on the switching
frequency, hence the ability to adjust it on this controller.
The option ranges between 100 ns and 2 us. The dead-
time is actually made by controlling the oscillator
discharge current. Figure 39 portrays a simplified VCO
circuit based on figure 31.
Figure 38. Thanks to the FB configuration, loop ORing is
In1
In2
If for any particular reason, there is a need for a
Dead-time control is an absolute necessity when
Vcc
easy to implement
FB
20k
VCO