an8015sh Panasonic Corporation of North America, an8015sh Datasheet - Page 9

• Manufacturer Part Number: an8015sh
• Description: Single-channel Step-down, Step-up, Or Inverting Use Dc-dc Converter Control Ic
• Manufacturer: Panasonic Corporation of North America

Voltage Regulators
[3] Function descriptions
1. Reference voltage block
2. Triangular wave oscillation block
3. Error amplifier block
4. Timer latch short-circuit protection circuit
R1
R2
Application Notes (continued)
V
OUT
voltage to the V
and used as the operating power supply for the IC inside. It is possible to take out a load current of up to 3 mA .
V
approximately 0.37 V will be generated by connecting a timing capacitor and a resistor to the CT terminal (pin 1) and
RT terminal (pin 2) respectively. The oscillation frequency can be freely decided by the value of C
connected externally.
inputs the amplified signal to the PWM comparator.
voltage with resistors.
resistor and capacitor between the error amplifier output terminal (pin 10) and the inverted input terminal (pin 9).
noninverted input terminal as shown in figure 3. 1), and the output voltage V
connecting to the inverted input terminal as shown in figure 3. 2). The output voltages in each of these cases are
given in the following equations.
destruction or deterioration if overload or short-circuit of power supply output lasts for a certain time.
voltage of DC-DC converter drops and the output level of error amplifiers exceeds 1.85 V, the low-level output is
given and the timer circuit is actuated to start the charge of the external protection enable capacitor.
this capacitor reaches 1.83 V, it sets the latch circuit, cuts off the output drive transistor, and sets the dead-time at
100%.
REF
R3
R4
V
V
This block is composed of the band gap circuit, and outputs the temperature compensated 2.46 V reference
Also, an overcurrent protection circuit is built in for the load, thereby protecting the IC from destruction when
The triangular wave which swings from the highest wave of approximately 1.4 V to the lowest wave of
The triangular wave is connected with the inverted input of PWM comparator of the IC inside.
This block detects the output voltage of DC-DC converter by the PNP transistor input type error amplifier, and
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 inserting the feedback
The output voltage V
This circuit protects the external main switching devices, flywheel diodes, and choke coils, etc. from
The timer latch short-circuit protection circuit detects the output level of the error amplifier. When the output
If the output of the error amplifier does not return to a normal voltage range by the time when the voltage of
OUT
IN
terminal is short circuited.
1) If output is positive
V
V
V
REF
IN
IN
IN
REF
REF
terminal (pin 7). The reference voltage is stabilized when the supply voltage is 3.6 V or higher,
7
8
9
R1 R2
R3 R4
R
C
Error amp.
NF
NF
R2
R4
OUT
Figure 3. Connection method of error amplifier
, if positive, is obtained by connecting the resistor-divided reference voltage to the
PWM comparator
input
R1
R2
V
V
OUT
IN
R3
R4
V
OUT
V
REF
2) If output is negative
(V
V
IN
IN
REF
REF
R1 R2
7
8
9
V
R2
R
C
OUT
Error amp.
IN
NF
NF
, if negative, is obtained by
)
R3 R4
R3
PWM comparator
input
AN8015SH
V
REF
T
and R
9
T