an8032 Panasonic Corporation of North America, an8032 Datasheet - Page 15

• Manufacturer Part Number: an8032
• Description: Active Filter Control Ic
• Manufacturer: Panasonic Corporation of North America

Voltage Regulators
[2] Operation descriptions (continued)
2. Protection circuit (continued)
Application Notes (continued)
2) Overvoltage protection
(1) Cause of overvoltage
Under light load
Under light load
Multiplier output
Power MOS
off-time current
Multiplier output
Power MOS
off-time current
Power MOS
on-time current
Power MOS
on-time current
load current reaches zero. However, in the actual condition, the input power can not be decreased to zero.
The output voltage is brought to out of control state, so that it rises.
of the switching device, so that the control to stop the operation of switching device becomes impossible.
(Refer to figure 10.)
tion circuit, so that the number of component to be added to the external part is drastically reduced.
In the booster chopper circuit, control is carried out so that the input power becomes zero when the
The cause of the out-of-control condition is that there is a delay time from the turn-on to the turn-off
In order to prevent the occurrence of such problem, the AN8032 has the built-in overvoltage protec-
Input voltage
0 A
0 A
Under no load condition, this voltage decreases to around 0 V.
At this time, the frequency of power MOS current rises,
however, there is circuit delay, so that the current does not reach 0 A.
Power MOS on-time current
Figure 10. Explanation of operation
AN8032
Power MOS off-time current
SBD
Output voltage
AN8032
Time
Time
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