an8032 Panasonic Corporation of North America, an8032 Datasheet - Page 14

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

AN8032
14
[2] Operation descriptions (continued)
2. Protection circuit
Application Notes (continued)
1) Timer
device. The chopper circuit does not re-start, if the turn-on timing of switching device is missed due to some
abnormality.
every approx. 400 s (typical) when the chopper circuit stops, eliminating the need for an external part to cope
with this problem. (Refer to figure 9.) However, in order to prevent the output rise of the chopper circuit, the
timer circuit does not operate as long as the overvoltage protector is operating.
When abnormal stop
When operation start
Power MOSFET current
In control of this IC, the chopper circuit does not start unless the first on-signal is input to the switching
For the above reasons, this IC is incorporating the timer circuit and generating the start pulse once in
Power MOSFET current
Timer trigger
signal (signal
inside the IC)
Timer trigger
signal (signal
inside the IC)
Input voltage
Input voltage
Input voltage applied
operation start
0 A
0 V
0 A
0 V
Figure 9. Explanation of timer operation
400 s typ.
Abnormal stop
Timer start
One-shot pulse
Start
400 s typ.
One-shot pulse
Re-start
Voltage Regulators
Time
Time
Time
Time