Datasheet AN8015SH Datasheet (Panasonic)

Voltage Regulators

AN8015SH

Single-channel step-down, step-up, or inverting use
DC-DC converter control IC

■ Overview

The AN8015SH is a single-channel DC-DC converter

control IC using the PWM method.

This IC can provide any one output type from among

step-down, step-up and inverting output.

Its operating supply voltage range is wide and its
consumption current is small. In addition, since it uses the
10-pin surface mounting type package with 0.5 mm pitch,
it is suitable for highly efficient miniature potable power
supply, especially for a negative output power supply.

■ Features

• Wide operating supply voltage range (3.6 V to 34 V)

• Small consumption current (1.8 mA typical)

• Converter control in a wide output frequency range is

possible (2 kHz to 500 kHz).

• Built-in timer latch short-circuit protection circuit (charge current 1.1 µA typical)

• Incorporating the under-voltage lock-out (U.V.L.O.) circuit

• Incorporating a high precision reference voltage circuit (2.46 V (allowance: ± 3%))

• Output block is open-collector (darlington) type.

• High absolute maximum rating of output current (100 mA)

• Maximum duty ratio is fixed and has small sample-to-sample variations (90% ± 5%).

• Using 10-pin small outline package of 0.5 mm pitch

0.5±0.2

1

5

0.5

0.1±0.1

4.3±0.30

6.3±0.30

SSOP010-P-0225

10

6

+0.1

–0.05

0.15

Unit: mm

0.2±0.1

0.625±0.100.625±0.10

3.0±0.30

1.5±0.2

■ Applications

• LCD displays, digital still cameras, and PDAs

■ Block Diagram

IN+
IN−

FB

Error amp.

8

9
10

CC

V

6

Reference

supply

2.46 V
(allowance : ± 3%)

S.C.P. comp.

1.83 V

REF

V

7

CT1RT

2

0.5 V

Triangular
wave OSC

I

1.2 V

0.37 V

V

REF

SR

Latch

PWM
comparator

1.11 V

RO

U.V.L.O.

5

4

Out

GND

Clamp

3

S.C.P.

1

AN8015SH Voltage Regulators

■ Pin Descriptions

Pin No. Symbol Description

1 CT Pin for connecting oscillator timing capacitor
2 RT Pin for connecting oscillator timing resistor
3 S.C.P. Pin for connecting the time constant setting capacitor for short-circuit protection
4 GND Grounding pin
5 Out Open collector type output pin
6VCCPower supply voltage application pin
7V

REF

8IN+ Error amplifier noninverted input pin
9IN− Error amplifier inverted input pin

10 FB Output pin of error amplifier

■ Absolute Maximum Ratings

Parameter Symbol Rating Unit

Supply voltage V
IN− terminal allowable application voltage V
IN+ terminal allowable application voltage V
Output terminal allowable application voltage V
Collector output current I
Power dissipation
Operating ambient temperature
Storage temperature

Note)*: Expect for the power dissipation, operating ambient temperature, and storage temperature, all ratings are for Ta = 25°C.

Reference voltage output pin

*

*

*

OUT

P

T

T

CC

IN−

IN+

OUT

D

opr

stg

35 V

− 0.3 to V

− 0.3 to V

REF

REF

35
100 mA
154 mW

−30 to +85 °C

−55 to +150 °C

■ Recommended Operating Range

Parameter Symbol Range Unit

Error amplifier input voltage V
Collector output voltage V
Collector output current I
Timing capacitance C
Timing resistance R
Oscillation frequency f
Reference voltage output current I

Soft start short-circuit protection time C
constant setting capacitance

2

OUT

OUT

OUT

RE

SCP

IN

− 0.1 to 0.8 V

34 (maximum) V
50 (maximum) mA

T

T

100 to 27 000 pF

5.6 to 15 kΩ

2 to 500 kHz

−3 to 0 mA

1 000 (minimum) pF

Voltage Regulators AN8015SH

■ Electrical Characteristics at VCC = 12 V, RT = 15 Ω, CT = 200 pF, Ta = 25°C

Parameter Symbol Conditions Min Typ Max Unit

Reference voltage block

Reference voltage V
Input regulation with input fluctuation
Input regulation with input fluctuation 2

REFIREF

Line

Line2 VCC = 3.6 V to 20 V 10 mV
Load regulation Load I
Output voltage temperature V

TC1

characteristics 1
Output voltage temperature V

TC2

characteristics 2
Reference short-circuit current I

RS

U.V.L.O. block

Circuit operation start voltage V
Hysteresis width V

UON

HYS

Error amplifier block

Input offset voltage V
Input bias current I
Common-mode input voltage range V
High-level output voltage V
Low-level output voltage V
Output sink current I
Output source current I
Open-loop gain A

IO

B

ICR

EH

EL

SINK

SOURCEVFB

V

Common-mode ripple rejection ratio CMRR  50  dB

Output block

Oscillation frequency f
Maximum duty ratio Du
Output saturation voltage V
Output leak current I

RT terminal voltage V
Maximum oscillation frequency f
Frequency supply voltage f

OUT

maxRT

OLIO

LEAKVCC

RT

OUT(max)RT

dV

characteristics VCC = 3.6 V to 34 V
Frequency temperature characteristics 1

Frequency temperature characteristics 2

f

dT1fOUT

f

dT2fOUT

= −1 mA 2.386 2.46 2.534 V

VCC = 3.6 V to 34 V, I

= − 0.1 mA to −1 mA  210mV

REF

= −1 mA

REF

 520mV

Ta = −30°C to +25°C ± 0.5  %

Ta = 25°C to 85°C ± 0.5  %

−20  mA

2.8 3.1 3.4 V

100 200 300 mV

−6  6mV

−500 −25  nA

− 0.1  0.8 V

V

− 0.3 V

− 0.1

REF

REF

 V

 0.1 0.3 V

VFB = 0.8 V  8  mA

= 0.8 V −120 µA

 70  dB

RT = 15 kΩ, CT = 200 pF 175 195 215 kHz

= 15 kΩ, CT = 200 pF 85 90 95 %

= 50 mA, RT = 15 kΩ0.9 1.2 V

= 34 V, 10 µA

when output transistor is off

 0.5  V

= 5.6 kΩ, CT = 150 pF  500  kHz

f

= 200 kHz, ±2  %

OUT

= 200 kHz,

±3  %

Ta = −30°C to +25°C

= 200 kHz,

±3  %

Ta = 25°C to 85°C

3

AN8015SH Voltage Regulators

■ Electrical Characteristics at VCC = 12 V, RT = 15 Ω, CT = 200 pF, Ta = 25°C (continued)

Parameter Symbol Conditions Min Typ Max Unit

Short-circuit protection circuit block

Input threshold voltage V
Input standby voltage V
Input latch voltage V
Charge current I
Comparator threshold voltage V

THPC

STBY

IN

CHG

THL

V

= 0 V −1.32 −1.1 − 0.88 µA

SCP

Whole device

Total consumption current I
Total consumption current 2 I

RT = 15 kΩ1.8 2.8 mA

CC

RT = 5.6 kΩ, CT = 150 pF 2.5  mA

CC2

■ Terminal Equivalent Circuits

Pin No. Equivalent circuit Description I/O

1 CT: O

V

REF

To PWM input

OSC
comp.

210

The terminal used for connecting a timing capaci­tor to set oscillation frequency.

I

O

Use a capacitance value within the range of 100 pF
to 27 000 pF.

1

Use a oscillation frequency in the range of 2 kHz
to 500 kHz.

1.73 1.83 1.93 V

1.15 1.25 1.35 V

 30 120 mV

 1.83  V

2 RT: I

V

REF

The terminal used for connecting a timing resistor
to set oscillation frequency.
Use a resistance value within the range of 5.6 kΩ
to 15 kΩ . The terminal voltage is 0.5 V typ.

OSC PWM

100 Ω

2

RT(VRT ≈ 0.5 V)

3 S.C.P.: O

V

REF

S.C.P.

The terminal used for connecting a capacitor to set

I

CHG

CT

PWM

the time constant of soft start and timer latch short­circuit protection circuit.

S.C.P.

Latch
S

Q

R

1.83 V

3

Use a capacitance value in the range of more than
1 000 pF.
The charge current is about 1.1 mA at R

V

I

CHG

RT

=

R

T

×1[A]

30

= 15 kΩ

T

4 GND: 

Grounding terminal

4

4

Voltage Regulators AN8015SH

■ Terminal Equivalent Circuits (continued)

Pin No. Equivalent circuit Description I/O

5 Out: O

V

REF

Open-collector type (darlington) output terminal.
The absolute maximum rating of output current is

5

100 mA
Use with a steady-state output current under 50
mA.

6V

6

: 

CC

The terminal for applying supply voltage.
Use with a operating supply voltage within the
range of 3.6 V to 34 V.

7V

V

CC

V

overcurrent detection

REF

:O

REF

The output terminal for the reference voltage (2.46
V)
Use with a load current −3 mA or under.
This terminal is incorporating the short-circuit

Bias to other block

7

protection circuit, and the short-circuit current is
about −20 mA. Use the V

for the reference

REF

input setting of the error amplifier.

8IN+:I

V

REF

The noninverted input terminal of the error ampli­fier.
For common-mode input, use in the range of − 0.1
V to +0.8 V.

9IN−:I

89

The inverted input terminal of the error amplifier.
For common-mode input, use in the range of − 0.1
V to +0.8 V.

10 FB: O

V

REF

120 µA

CT

PWM

The output terminal of the error amplifier.
The source current is about −120 µA, and the sink
current is about 8 mA.
Correct the frequency characteristics of the gain

8 mA

10

and the phase by connecting a resistor and a ca­pacitor between this terminal and IN− terminal.

5

AN8015SH Voltage Regulators

■ Application Notes

[1] Main characteristics

Reference voltage temperature characteristics Maximum duty ratio temperature characteristics

(V)

REF

2.50

2.49

2.48

2.47

VCC = 12 V
I

= −1 mA

REF

(%)

max

91.0

90.5

90.0

VCC = 12 V
C

= 200 pF

T

= 15 kΩ

R

T

Reference voltage V

2.46

2.45

−40 −20 100

Ambient temperature Ta (°C)

806040200

89.5

Maximum duty ratio Du

89.0

−40 −20 100

Ambient temperature Ta (°C)

806040200

Oscillation frequency temperature characteristics Timing capacitance  Oscillation frequency

200

195

(kHz)

OUT

190

185

VCC = 12 V
C

= 200 pF

T

R

= 15 kΩ

T

Oscillation frequency f

180

−40 −20 100

806040200

Ambient temperature Ta (°C)

Maximum duty ratio  Oscillation frequency

(%)

max

Maximum duty ratio Du

100

90

R

T

80

R

T

= 15 kΩ

= 5.6 kΩ

VCC = 12 V

= 25°C

T

a

1 M

RT = 5.6 kΩ

VCC = 12 V
T

= 25°C

a

(Hz)

100 k

OUT

10 k

= 15 kΩ

R

T

RT = 10 kΩ

Oscillation frequency f

1 k

100 00010 0001 000100

Timing capacitance CT (pF)

Oscillation frequency  Triangular wave maximum
amplitude voltage

1.4

(V)

1.2

1.0

0.8

0.6

0.4

0.2

VCC = 12 V
R

= 15 kΩ

T

T

= 25°C

a

70

10k 100k 1M

Oscillation frequency f

6

OUT

(Hz)

Triangular wave maximum amplitude voltage

0

10k 100k 1M

Oscillation frequency f

OUT

(Hz)

Voltage Regulators AN8015SH

■ Application Notes (continued)

[1] Main characteristics (continued)

Supply voltage  Reference voltage Supply voltage  Total consumption current

(V)

REF

3.0

Ta = 25°C

= −1 mA

I

REF

2.5

2.0

1.5

(mA)

CC

3.0

Ta = 25°C

2.5

RT = 5.6 kΩ

2.0

RT = 15 kΩ

1.5

1.0

1.0

Reference voltage V

0.5

0

05

1

2 3 4

0.5

Total consumption current I

0

05

Supply voltage VCC (V)

Reference voltage line regulation Total consumption current line regulation

2.52

2.50

Ta = 25°C
I

REF

(V)

REF

2.48

2.46

Reference voltage V

2.44

2.42
05 35

Supply voltage VCC (V)

= −1 mA

3025201510

3.0

(mA)

CC

2.5

2.0

Total consumption current I

1.5
05 35

1

2 3 4

Supply voltage VCC (V)

RT = 5.6 kΩ

RT = 15 kΩ

Supply voltage VCC (V)

Ta = 25°C

3025201510

Timing resistance  Total consumption current Timing resistance  Output saturation voltage

0.85

0.84

(V)

OL

0.83

0.82

0.81

Output saturation voltage V

0.80
420

8 12 16

VCC = 12 V
T

= 25°C

a

I

= 50 mA

O

Timing resistance RT (kΩ)

(mA)

CC

2.5

2.0

1.5

VCC = 12 V

= 25°C

T

a

Total consumption current I

1.0
420

8 12 16

Timing resistance RT (kΩ)

7

AN8015SH Voltage Regulators

■ Application Note (continued)

[2] Timing chart

3.1 V typ.

V

REF

(V

t

r

rise time

) ≥ 10 [µs]

REF

Lock-out release

Supply voltage (V

Reference voltage (V

CC

REF

)

3.6 V

)

2.46 V

Error amplifier output (FB)

Power supply
on

Triangular wave (CT)

S.C.P. terminal voltage

Output transistor collector waveform
(Out)

Figure 1. PWM comparator operation waveform

Reference voltage (V

REF

)

Short-circuit protection input threshold level
Comparator threshold level

S.C.P. terminal voltage
Dead-time voltage (V

DT

)
Error amplifier output (FB)
Triangular

wave (CT)

Output transistor
collector waveform (Out)

Dead-time voltage (V

DT

)

Soft start operation Maximum duty 90%

1.83 V

1.20 V

1.11 V

0.37 V

High

Low

2.46 V

1.83 V

1.20 V

1.11 V

0.37 V

0.03 V
High

Low

Short-circuit protection
comparator output

8

Figure 2. Short-circuit protection operation waveform

t

PE

High

Low

Voltage Regulators AN8015SH

■ Application Notes (continued)

[3] Function descriptions

1. Reference voltage block
This block is composed of the band gap circuit, and outputs the temperature compensated 2.46 V reference

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 .

Also, an overcurrent protection circuit is built in for the load, thereby protecting the IC from destruction when

V

terminal is short circuited.

REF

2. Triangular wave oscillation block
The triangular wave which swings from the highest wave of approximately 1.4 V to the lowest wave of

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.

The triangular wave is connected with the inverted input of PWM comparator of the IC inside.

3. Error amplifier block
This block detects the output voltage of DC-DC converter by the PNP transistor input type error amplifier, and

inputs the amplified signal to the PWM comparator.

The common-mode input voltage range is − 0.1 V to 0.8 V, and is a voltage obtained by dividing the reference

voltage with resistors.

Also, it is possible to perform the gain setting and the phase compensation arbitrarily by inserting the feedback

resistor and capacitor between the error amplifier output terminal (pin 10) and the inverted input terminal (pin 9).

The output voltage V

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.

terminal (pin 7). The reference voltage is stabilized when the supply voltage is 3.6 V or higher,

REF

T

, if positive, is obtained by connecting the resistor-divided reference voltage to the

OUT

, if negative, is obtained by

OUT

and R

T

R1

R2

V

OUT

V

= V

V

R3

R4

OUT

IN+

= V

IN+

REF

V

REF

IN+ 8
IN− 9

1) If output is positive

R1 + R2

×

×

R3 + R4

7

R

C

R2
R4

Error amp.

NF

NF

PWM comparator
input

FB 10

R1

R2

V

V

= − (V

OUT

IN−

R3

R4

V

= V

OUT

REF

REF

V

REF

IN+ 8
IN− 9

2) If output is negative

− V

×

R1 + R2

R2

7

R

C

R3 + R4

×

)V

IN−

Error amp.

NF

NF

R3

REF

PWM comparator
input

FB 10

Figure 3. Connection method of error amplifier

4. Timer latch short-circuit protection circuit
This circuit protects the external main switching devices, flywheel diodes, and choke coils, etc. from

destruction or deterioration if overload or short-circuit of power supply output lasts for a certain time.

The timer latch short-circuit protection circuit detects the output level of the error amplifier. When the output

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.

If the output of the error amplifier does not return to a normal voltage range by the time when the voltage of

this capacitor reaches 1.83 V, it sets the latch circuit, cuts off the output drive transistor, and sets the dead-time at
100%.

9

AN8015SH Voltage Regulators

■ Application Notes (continued)

[3] Function descriptions (continued)

5. Low input voltage malfunction prevention circuit (U.V.L.O.)
This circuit protects the system from destruction or deterioration due to control malfunction when the supply

voltage is low in the transient state of power on/off.

The low input voltage malfunction prevention circuit detects the internal reference voltage which changes

according to the supply voltage level. Until the supply voltage reaches 3.1 V during its rise time, it cuts off the the
output drive transistor, sets the dead-time at 100% and holds the S.C.P. terminal (pin 3) to low level. During the
fall time of the power supply voltage, it has hysteresis width of 200 mV and operates 2.9 V or less.

6. PWM comparator block
The PWM comparator controls the on-period of the output pulse according to the input voltage. It turns on the

output transistor during the period when the triangular wave of CT terminal (pin 1) of noninverted input is lower
than any one of the following voltages : the voltage of the error amplifier output (pin 10) of the inverted input, S.C.P.
terminal (pin 3), and the voltage for dead-time which is fixed inside the IC.

The S.C.P. terminal voltage is kept at 1.25 V in the state in which DC-DC converter output is stabilized.

However, when the power supply is turned on, the soft start is activated, which gradually extends on-period
according to the time constant determined by the capacitance of externally attached capacitor and the charge current.
The maximum duty ratio is fixed at approximately 90% by the voltage for dead-time.

7. Output block
The output drive transistor is of open-collector type output connected in darlington circuit of emitter common

GND. The breakdown voltage of collector output terminal (pin 5) is 34 V and it is possible to obtain up to 100 mA
output current.

[4] Triangular wave oscillation circuit

1. Oscillation frequency setting method
The waveform of triangular wave oscillation is obtained by charging and discharging of the constant current

I

from the external timing capacitor CT which is connected to CT terminal (pin 1). The constant current is set by

O

the externally attached timing resistor R

The peak value of the wave V

value of the wave V

are fixed at approximately 1.4 V

CTL

.

T

and the trough

CTH

V

CTH

typical and 0.37 V typical respectively.

The oscillation frequency f

following formula;

f

OSC

1

=

t1 + t

2

whereas IO = 2 ×
because V
f

=

OSC

CTH

1

1.66 × C

The output frequency f

=

2 × CT × (V

V

R

− V

× R

T

T

is obtained by the

OSC

I

RT

= 2 ×

T

= 0.83 V

CTL

is equal to f

OUT

O
CTH

0.5
R

− V

)

CHL

T

since it is PWM-controlled.

OSC

V

t

t

Charging Discharging

2

1

CTL

T

Figure 4. Triangular wave oscillation waveform

= 1.4 V typ.

= 0.37 V typ.

10

Voltage Regulators AN8015SH

■ Application Notes (continued)

[4] Triangular wave oscillation circuit (continued)

2. Usage notes
This IC uses the constant current given by the timing resistor R

block and the PWM comparator for consumption current reduction. The total consumption current is approximately

1.8 mA (typical) when R

is 15 kΩ, and it increases to approximately 2.5 mA (typical) when RT is 5.6 k Ω. In order

T

to obtain the steady-state output current of 100 mA at the open collector output, it is necessary to set R
15 kΩ or smaller.

It is possible to use the circuit in the recom-

mended operating range of 2 kHz to 500 kHz of the
oscillation frequency. However, the timing resistor
R

versus the oscillation frequency should be set

T

within the recommended range shown in figure 5.
Also, refer to the "Applications Notes, [1] Main
characteristics, Timing capacitance  Oscillation
frequency" for setting the timing capacitance.

For a high frequency use, the overshoot and un-

dershoot amounts increase due to operation delay
of the triangular oscillation comparator, and the
maximum duty ratio drops. This effect can be alle­viated by speeding up through the reduction of the
resistor R

and increase in the circuit current.

T

Note that this IC can not be used as an IC for

slave when the several ICs are operated in parallel
synchronous mode.

as the bias current of the triangular oscillation

T

value to

T

1 M

500 k

(Hz)

Oscillation frequency f

100 k

OUT

10 k

1 k

Recommended operating

condition

10 k

Timing resistance RT (Ω)

15 k5 k 5.6 k

Figure 5. Timing resistance recommended condition

[5] Time constant setting method for short-circuit protection circuit with joint-use of soft start/timer latch type

The constructional block diagram of protection latch circuit is shown in figure 6. The comparator for short-circuit

protection compares the output of error amplifier V

with the reference voltage of 1.85 V at all the time.

FB

When the load conditions of DC-DC converter output is stabilized, there is no fluctuation of error amplifier
output and the short-circuit protection comparator also keeps the balance. At this moment, the output transistor Q1 is
in the conductive state and the S.C.P. terminal is hold to approximately 1.25 V through the clamp circuit.

When the load conditions suddenly change, and high-level signal (1.85 V or higher) is input from the error amplifier
to the noninverted input of the short-circuit protection comparator, the short-circuit protection comparator outputs the
low-level signal. Since this signal cuts off the output transistor Q1, the S.C.P. terminal voltage V
externally connected capacitor C

= V

V

PE

1.83 V = 1.25 V + I

CS = I

I

is the constant current determined by the oscillation timing resistor RT and its dispersion and fluctuation with

CHG

temperature are small. I

I

CHG

V

is approximately 0.5 V and I

RT

+ I

t

PE

0.58

×

1

30

CHG

×

CHG

[F]

CHO

[A]

STBY

×

CHG

V

RT

=

R

T

starts charging according to the following equation:

S

t

PE

[V]

C

S

t

PE

×

C

S

is expressed in the following equation:

becomes approximately 1.1 µA when RT = 15 kΩ.

CHO

is released, and the

PE

11

AN8015SH Voltage Regulators

■ Application Notes (continued)

[5] Time constant setting method for short-circuit protection circuit with joint-use of soft start/timer latch type

(continued)

When the external capacitor C
output drive transistor by enabling the low input voltage malfunction prevention circuit, and sets the dead-time at 100%.

The low input voltage malfunction prevention circuit is once enabled, the S.C.P. terminal voltage is discharged to
approximately 30 mV but the latch circuit is not reset unless the power is turned off.

The S.C.P. terminal voltage is inputted to the PWM comparator, and the soft start is actuated when the power turns
on. However, since at the beginning of power on, the error amplifier output is high level, and V
voltage is released and charging begins; the external capacitor should be set so that the output voltage of DC-DC
convertor starts to rise before the latching circuit is set. The charging equation is as same as the above. The soft start
time t

until the input standby voltage V

SS

1.25 V = 0.03 V + I

tSS = 1.22 ×

Error amp.

8

IN+

9

IN−

10

FB

I

C

CHG

CHG

S

[s]

has been charged up to approximately 1.83 V, it sets the latch circuit, cuts off the

S

of S.C.P. terminal

PE

becomes 1.25 V is given in the following equations:

STBY

t

SS

×

C

S

I

1.25 V

S.C.P. comp.

Q1

CHG

Clamp
circuit

SR

Latch

Q2

PWM comparator input

R

U.V.L.O.

Output cut-off

1.83 V

3

V

REF

C

S

S.C.P.

Figure 6. Short-circuit protection circuit

12

Voltage Regulators AN8015SH

■ Application Circuit Examples

1. Chopper method step-down type

V

120 kΩ

CC

1 000 pF

3.6 kΩ

FB10

1
CT

IN−9

2
RT

200 pF 0.1 µF15 kΩ

2. Chopper method inverting type

120 kΩ

3.6 kΩ

1 000 pF

FB10

IN−9

0.1 µF

8.2 kΩ

IN+8

3

S.C.P.

REF7

V

4

GND

130 kΩ

CC6

V

5

Out

V

CC

0.1 µF

8.2

9.1

kΩ

kΩ

IN+8

REF

V

7

CC

V

6

25.5 kΩ

SBD

4.5 kΩ

SBD

V
5 V

V

O

−24 V

O

1

CT

2
RT

200 pF 0.1 µF15 kΩ

3

S.C.P.

4

GND

5

Out

13

AN8015SH Voltage Regulators

■ Application Circuit Examples (contined)

3. On/off circuit example

C7

V

CC

V

Q1

I

CC

SBD

1) Method to cut V

Standby current ≈ 0 µA

CC

line

O

FB

10

1

CT

IN−

9

2

RT

2) Method to cut S.C.P. line

Consumption current
when output off ≈ 1.8 mA

FB

10

IN−

9

REF

IN+

V

8

3

7

4

GND

S.C.P.

CC

V

C8

On/off

6

5

Out

V

CC

V

O

C8

I

REF

V

7

CC

CC

V

6

C7

IN+

8

SBD

1

CT

2

3

RT

S.C.P.

4

GND

5

Out

Q2

On/off

4. Using method

Since the on/off circuit is not incorporated in this IC, it is required to add on/off circuit externally to provide a
standby function.

When the switch (Q1) is inserted between the V

line and the Vcc pin of the IC (pin 6) as shown in 3. 1), the standby

CC

current is suppressed to 0. When the output is turned off by decreasing the S.C.P. terminal voltage below the lower
limit of the triangular wave (0.37 V typical) as shown in 3. 2), the consumption current does not decrease because the
IC is operating.

5. Usage notes

The rise time of the V
latch circuit of the IC is set so that the circuit fails to start. Adjust C7 or C8 so that the rise time for V

becomes sharp especially in the case of 3. 1). At that time, there is a case that the internal

CC

pin (pin 7)

REF

becomes 10 ms or longer.

14