an8032 Panasonic Corporation of North America, an8032 Datasheet - Page 16

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

AN8032
16
[2] Operation descriptions (continued)
2. Protection circuit (continued)
Application Notes (continued)
2) Overvoltage protection (continued)
Power MOSFET current
Operation condition
of active filter
Output voltage of
active filter
(2) Description of overvoltage protector operation
provided separately from the input of the overvoltage protection comparator. This is the point which
differs from the AN8031.
start up or abnormality occurrence, the overvoltage comparator operates to cut off the switching device.
further. Otherwise, the timer circuit will re-start the power MOSFET, and actuate it to increase the output
voltage further at the time of the overvoltage detection.
which is 5% higher than the normal control voltage and does not exceed that value. (Refer to figure 11.)
parator.
With respect to the AN8032 IC, the input of the error amplifier which detects the output voltage is
Each setting is shown as follows:
If the output voltage becomes more than 5% higher than the normal control voltage at the time of
The timer circuit is cut off when overvoltage is detected. This prevents the output voltage to increase
Therefore, under no load condition, the output voltage of the chopper circuit is stabilized at the value
The increase/decrease of the output voltage is created by the offset amount of the overvoltage com-
• Control reference voltage of the error amplifier: 2.50 V typical
• Detection voltage of the overvoltage comparator: 2.63 V typical [Without hysteresis]
(Voltage of 5% higher than the control reference voltage of the error amplifier)
420 V
400 V
0 A
Figure 11. Protection of overvoltage protection operation
Operating
Stabilized at 5% higher voltage
Stop
Operating
Stop
Voltage Regulators
Created by offset amount
of overvoltage comparator
Time