an8032 Panasonic Corporation of North America, an8032 Datasheet - Page 11

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

Voltage Regulators
[2] Operation descriptions (continued)
1. Normal control (continued)
Application Notes (continued)
3) Description of each function (continued)
(1) V
(2) CS
(3) MPI
<Setting the V
Zero-cross switching
the local resonance when turning on the power
MOSFET in order to suppress the loss.
tween the drain and source of the power MOSFET,
and using the inductance of the transformer's pri-
mary side L
charging the accumulated energy of the transformer.
The capacitor for delay should be connected to the
V
the time when the resonance occurred and the drain
voltage of the power MOSFET has reached around
0 V.
zero-cross conditions could deviate since the delay
amount varies depending on the conditions such as
the input voltage.
B
inductor. Therefore, the necessary power value can be controlled by controlling the peak value of the
above current.
the power MOSFET current detecting resistance is set at larger value. A value from 0.22
the standard considering the relationship with the S/N.
transformer or printed circuit wiring flow in the power MOSFET detection resistor at turning-on and off.
Since such current generates noise and causes malfunction, it is necessary to incorporate a filter to re-
move such irregular element.
from the input voltage after full-wave rectification is input. The input D-range of the multiplier is from
0 V to 4.5 V typical and output D-range is from 0 V to 5.4 V typical.
terminal so that the next turn-on could occur at
B
Zero-cross switching can be realized by using
By connecting the resonance capacitor C
However, it is necessary to take care that the
(continued)
The terminal for detecting the current when the power MOSFET is turned on.
The current flow when the power MOSFET is turned on is equivalent to the current flow in the
The input D-range of this terminal is from 0 V to 5 V. However, since dissipation becomes larger if
The charge and discharge current to and from the parasitic capacitance of the power MOSFET,
The MPI is the terminal for monitoring the AC input voltage. The voltage which is resistance-divided
V
B
B
P
, the resonance is produced after dis-
terminal constant> (continued)
Parasitic
capacitance
Filter
Figure 6. CS terminal explanation
I
CS
P
be-
B-point voltage
A-point voltage
0 A
AN8032
V
0 V
0 V
OUT
V
B
Power MOSFET
V
BTH
Delay capacitor
Spike
Spike
On
C
Resonance capacitor
B
Delay
B
Resonance by
A
Zero-cross
switching
Power MOSFET
C
R
AN8032
P
to 0.47
B
L
L
Off
P
P
C
11
P
is