Voltage Regulators
AN8032
■ Application Notes (continued)
[2] Operation descriptions (continued)
1. Normal control (continued)
3) Description of each function (continued)
(6) VCC
ICC
IC operation
U.V.L.O.
characteristics
The supply voltage terminal other than the
output. The U.V.L.O. depends on this VCC voltage.
(The characteristics of U.V.L.O. are shown in the
right figure.)
V
0
8
10
VCC
(Stop voltage) (Start voltage)
<Notes on the methods of providing VCC
>
• The method to give bias from sub-coil
Start resistance
R1
There is only 2 V typical difference between the
start voltage 10 V typical and the stop voltage 8 V
typical. Be careful that the value for C1 shown in the
right figure must be set at a large value, otherwise,
the IC does not easily start.
VCC
AN8032
VOUT
GND
C1
• Giving bias from power supply
In the case such as of fluorescent lamp inverter
circuit, separate power supply is provided so as to
give the bias from the separate power supply.
VCC
AN8032
To fluorescent lamp
inverter circuit block
C1
GND
<VCC interference>
For the AN8032, the following method is used to
suppress the interference between the two power
supply lines : The supply voltage supply line of the
power system and that for the signal line are sepa-
rately provided in the IC chip and they are put to-
gether when wired to the pin of the package. Thus
the interference between 2 power supply lines is sup-
pressed.
The same method is also used for the GND line.
However, the above method can not prevent all the
malfunctions due to noise. Therefore, in regard to
the current pass in which the drive current of the
power MOSFET flows, the pattern wiring should be
provided as short as possible, in the same way as
conventional practice to suppress the invasion of
noise of the drive system.
Totem pole type output circuit
PVCC R1
Drive current
at turning on
VOUT
R2
Drive current
at turning off
GND
13
PANASONIC [ PANASONIC ]
