an8011s Panasonic Corporation of North America, an8011s Datasheet - Page 10

• Manufacturer Part Number: an8011s
• Description: 2-channel Step-down, Step-up, Or Inverting Use Dc-dc Converter Control Ic
• Manufacturer: Panasonic Corporation of North America

AN8011S
10
[2] Function descriptions
1. Reference voltage block
2. Triangular wave oscillation block
3. Error amplifier block
Application Notes (continued)
voltage to the V
used as the operating power supply for the IC inside. It is possible to take out a load current of up to 3 mA. Also,
an overcurrent portection circuit is built in for the load, thereby protecting the IC from destruction when V
terminal is short circuited.
approximately 0.4 V will be generated by connecting a timing capacitor and a resistor to the CT terminal and RT
terminal respectively. The oscillation frequency can be freely decided by the value of C
externally. The triagular wave is connected with the inverted input of PWM comparator of the IC inside.
input type differential amplifier to the PWM comparator.
voltage with resistors.
feedback resistor and the capacitor from the error amplifier output terminal to the inverted input terminal.
noninverted input terminal as shown in figure 1. 1), and the output voltage V
connecting to the inverted input terminal as shown in figure 1. 2). The output voltages in each of these cases are
given in the following equations.
exclusively for positive voltage ouput, and
method of connection is as shown in figure 2.
V
This block is composed of the band gap circuit, and outputs the temperature compensated 2.5 V reference
The triangular wave which swings from the wave peak of approximately 1.4 V to the wave bottom of
This block detects the output voltage of DC-DC conveter, and inputs the signal amplified by the PNP transistor
The common-mode input voltage range is 0.1 V to 0.8 V, and is a voltage obtained by dividing the reference
Also, it is possible to perform the gain setting and the phase compensation arbitrarily by connecting the
The output voltage V
V
V
The output voltage of channel 2 V
V
OUT1
OUT1
IN
OUT2
R2
R1
V
V
REF
0.75
1) Positive output
R3
R4
V
IN
IN 1
IN
REF
REF
16
14
13
R1
R1
terminal. The reference voltage is stabilized when the supply voltage is 3.6 V or higher, and
R1
Error amp.1
R2
R2
R2
C
R
Figure 1. Connection method of error amplifier 1
R2
R2
NF
OUT
NF
R2
, if positive, is obtained by connecting the resistor-divided reference voltage to the
12
PWM comparator
input
FB1
OUT2
is
R2
R1
V
OUT2
Figure 2. Cnnection method of error amplifier 2
V
V
FB2
IN 2
OUT1
IN 1
R2
R1
V
4
5
OUT1
V
0.75V
2) Negative output
REF
R3
R4
R4
V
R3
(V
IN
IN 1
REF
REF
V
Error amp.2
16
14
13
R1
REF
Error amp.1
R2
V
C
: 2.5 V
R
IN-1
OUT
R2
NF
NF
)
Voltage Regulators
, if negative, is obtained by
R3
PWM comparator input
12
R3
PWM comparator
input
T
FB1
R4
and R
V
T
REF
connected
REF