Datasheet AN8013SH Datasheet (Panasonic)

Voltage Regulators

AN8013SH

Single-channel step-up or step-down
DC-DC converter control IC

■ Overview

The AN8013SH is a single-channel PWM DC-DC
converter control IC. This IC implements DC-DC con­verters that provide a single arbitrary output voltage that
is either a stepped-up or stepped-down level. It features a
wide operating supply voltage range, low power, and a
built-in overcurrent protection circuit to protect the
switching transistor from damage or destruction. The
AN8013SH is provided in a 0.5 mm pitch 10-pin surface
mounting package and is optimal for use in miniature
high-efficiency portable power supplies.

0.5±0.2

Unit: mm

1

5

0.5

0.1±0.1

4.3±0.30

6.3±0.30

10

0.2±0.1

6

0.625±0.100.625±0.10

+0.1

–0.05

0.15

3.0±0.30

1.5±0.2

■ Features

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

• Small consumption current (2.4 mA typical)

• Supports control over a wide output frequency range:

20 kHz to 500 kHz.

• Built-in pulse-by-pulse overcurrent protection circuit

(Detection voltage: V

− 100 mV)

CC

• Built-in timer latch short-circuit protection circuit

■ Pin Descriptions

CLM
RT
CT
S.C.P.
DTC

(charge current 1.3 µA typical)

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

• Built-in reference voltage circuit (Error amplifier reference input: 0.75 V (allowance: ±4%))

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

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

• Duty ratio with small sample-to-sample variations (55% ± 5%).

• Adopts a 0.5-mm lead pitch 10-pin small outline package

SSOP010-P-0225

1
2
3
4
5

■ Applications

• Switching mode power supply units (in portable equipment and other applications)

10

V

CC

9

Out

8

GND

7

IN−

6

FB

1

AN8013SH Voltage Regulators

■ Block Diagram

CC

FB

IN−

V

6

Error amp.

7

V

10

REF

0.75 V

0.1 V

CLM

1

S.C.P. comp.

1.90 V

DTC

5

V

REF

R

S R
Latch

V

REF

R

T

4

S.C.P.

T

0.75 V

V

REF

S R
Latch

PWM

R
S Q
U.V.L.O.

CT3RT

2

OSC

9

Out

8

GND

■ Absolute Maximum Ratings at Ta = 25°C

Parameter Symbol Rating Unit

Supply voltage V
CLM pin allowable application voltage V
Error amplifier allowable input voltage V
DTC pin allowable input voltage V
Out pin allowable application voltage V
Collector output current I
Power dissipation (Ta = 85°C) P
Operating ambient temperature T
Storage temperature T

CC

CLM

IN−

DTC

OUT

OUT

D

opr

stg

35 V
35 V

−0.3 to +2.5 V

2.5 V
35 V

100 mA
154 mW

−30 to +85 °C

−55 to +150 °C

■ Recommended Operating Range at Ta = 25°C

Parameter Symbol Min Max Unit

Supply voltage rise time (0 to 3.6 V) tr (VCC)10 µs
Collector output voltage V
Collector output current I
Timing capacitance C
Timing resistance R
Oscillator frequency f
Short-circuit protection time constant setting C

capacitor

OUT

OUT

T

T

OUT

SCP

 34 V
 50 mA

100 1 800 pF

5.1 15 kΩ

20 500 kHz

1 000  pF

2

Voltage Regulators AN8013SH

■ Electrical Characteristics at Ta = 25°C

Parameter Symbol Conditions Min Typ Max Unit

U.V.L.O. block

Circuit operation start voltage V
Hysteresis width V

UON

HYS

Error amplifier block

Input threshold voltage V
Line regulation with input fluctuation V

Voltage follower 0.72 0.75 0.78 m V

TH

Voltage follower,  28mV

dv

VCC = 3.6 V to 34 V
Input bias current I
High-level output voltage V
Low-level output voltage V
Input threshold voltage temperature V

B

EH

EL

Voltage follower, ±1  %

dt1

characteristics 1 Ta = −30°C to +25°C
Input threshold voltage temperature V

Voltage follower, ±1  %

dt2

characteristics 2 Ta = −25°C to +85°C
Output sink current I
Output source current I

SOURCEVFB

Open-loop gain A

VFB = 0.9 V  8  mA

SINK

= 0.9 V −120 µA

V

PWM Comparator Block

Input threshold voltage: high V
Input threshold voltage: low V
Input current I

Duty: 100% 1.2  V

DT-H

Duty: 0% 0.6 V

DT-L

DTC

Output block

Oscillation frequency f
Output duty Du R
Output saturation voltage V
Output leak current I
RT pin voltage V
Maximum oscillation frequency f

OUT(max)RT

Frequency supply voltage f

RT = 15 kΩ, CT = 150 pF 185 205 225 kHz

OUT

= 91 kΩ 50 55 60 %

DTC

OLIO

LEAKVCC

RT

= 50 mA, RT = 15 kΩ0.9 1.2 V

= 34 V, when output Tr is off 10 µA

= 5.1 kΩ, CT = 120 pF  500  kHz

f

dV

= 200 kHz, ±1  %

OUT

characteristics VCC = 3.6 V to 34 V
Frequency temperature f

dT1fOUT

characteristics 1
Frequency temperature f

dT2fOUT

characteristics 2

Note)

At VCC = 12 V, RT = 15 kΩ, CT = 15 pF, unless otherwise specified.

= 200 kHz,

Ta = −30°C to +25°C

= 200 kHz,

Ta = 25°C to 85°C

2.8 3.1 3.4 V

100 200 300 mV

−500 −25  nA

2.0  V

0.3 V

 70  dB

−12 −11 −10 A

 0.59  V

±3  %

±3  %

3

V

CC

CLM
comp.

50 µA50 µA

0.1 V

1

AN8013SH Voltage Regulators

■ Electrical Characteristics at 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 −1.6 −1.3 − 1.0 µA

SCP

Overcurrent Protection Block

Input threshold voltage V
Delay time t

CLM

DLY

Whole device

Total consumption current 1 I
Total consumption current 2 I

Note)

At VCC = 12 V, RT = 15 kΩ, CT = 15 pF, unless otherwise specified.

RT = 15 kΩ2.4 3.5 mA

CC

RT = 5.1 kΩ, CT = 150 pF 3.4mA

CC2

■ Terminal Equivalent Circuits

Pin No. Pin I/O Function Internal equivalent circuit

1 CLM I Detects the overcurrent state in switching

transistor.
Insert a resistor with a low resistance between
this pin and V
When this pin falls to a level 100 mV or more
lower than VCC, the PWM output is turned off
for that period thus narrowing the width of
the on period.
(This implements a pulse-by-pulse
overcurrent protection technique.)

2 RT I Connection for the timing resistor that deter-

mines the oscillator frequency.
Use a resistor in the range 5.1 kΩ to 15 kΩ.
Thus the pin voltage will be about 0.59 V.

3 CT O Connection for the timing capacitor that

determines the oscillator frequency.
Use a capacitor in the range 100 to 1 800 pF.
See the "Application Notes, [2] and [3]"
sections later in this document for details on
setting the frequency. Use an oscillator
frequency in the range 20 kHz to 500 kHz.

to detect overcurrent states.

CC

V

V

To PWM input

0.70 0.75 0.80 V

120 V
120 mV

 1.90  V

VCC − 120 VCC − 100 VCC − 80

 200  ns

REF

100 Ω

RT (V ≈ 0.59 V)

2

REF

OSC
comp.

OSC PWM

S.C.P.

mV

DTC

2I

I

O

3

O

4

Voltage Regulators AN8013SH

■ Terminal Equivalent Circuits (continued)

Pin No. Pin I/O Function Internal equivalent circuit

4 S.C.P. O Connection for the capacitor that determines

the time constant for soft start and the timer
latch short-circuit protection circuit.
Use a capacitor with a value of 1 000 pF or
higher.
The charge current I

is determined by the

CHG

timing resistor RT, and sample-to-sample and
temperature variations can be suppressed.
When R

is 15 kΩ, the current will be about

T

−1.3 µA.

I

CHG

V

=

R

RT

1

×

[A]

30

T

5 DTC I Connection for the resistor and capacitor that

determine the PWM output dead-time and the
soft start period.
The input current I

is determined by the

DTC

timing resistor RT, and sample-to-sample and
temperature variations can be suppressed.
When R

is 15 kΩ, the current will be about

T

−11 µA.

I

CHG

V

=

R

RT

1

×

[A]

3.6

T

6 FB O Error amplifier output

A source current is about −120 mA and a sink
current is about 8 mA.
Correct the gain and the phase frequency
characteristics by inserting a resistor and a
capacitor between this pin and IN−pin.

7IN− I Error amplifier inverting input

For common-mode input, use in the range

− 0.1 V to +0.8 V.

V

REF

U.V.L.O.

V

REF

U.V.L.O.

V

REF

V

REF

I

CHG

0.75 V

Latch

S
R

Q

4

I

DTC

CT

PWM

5

120 µA

8 mA

PWM

C

T

6

8 GND  Ground

0.75 V

7

8

5

AN8013SH Voltage Regulators

V

REF

9

■ Terminal Equivalent Circuits (continued)

Pin No. Pin I/O Function Internal equivalent circuit

9 Out O Open-collector (darlington) output

The absolute maximum rating for the output
current is 100 mA.
Use with a constant output current under 50
mA.

10 V

CC

 Power supply connection

Provide the operating supply voltage in
the range 3.6 V to 34 V.

■ Application Notes

[1] Main characteristics

Error amplifier input threshold voltage temperature
characteristics

0.760

= 12 V

V

CC

Voltage follower

0.758

(V)

TH

0.756

0.754

0.752

Input threshold voltage V

0.750

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

10

Maximum duty ratio temperature characteristics

60

= 12 V

V

CC

= 200 pF

C

T

= 15 kΩ

R

T

58

(%)

max

56

54

Maximum duty ratio Du

52

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

Oscillator frequency temperature characteristics Timing capacitance  Oscillator frequency

215

210

(kHz)

OUT

205

200

V

CC

= 200 pF

C

T

= 15 kΩ

R

T

= 12 V

Oscillator frequency f

195

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

1M

(Hz)

OUT

100k

RT = 15 kΩ

RT = 5.1 kΩ

Oscillator frequency f

10k

100 1 000 10 000

Timing capacitance CT (pF)

V

CC

= 25°C

T

a

= 12 V

6

Voltage Regulators AN8013SH

■ Application Notes (continued)

[1] Main characteristics (continued)

Input threshold voltage line regulation Total consumption current line regulation

(V)

TH

0.765

0.760

= 25°C

T

a

(mA)

CC

4.0

3.5

RT = 5.1 kΩ

= 25°C

T

a

0.755

0.750

Input threshold voltage V

0.745
0 5 10 15 20 25 30 35

Supply voltage VCC (V)

3.0

2.5

RT = 15 kΩ

Total consumption current I

2.0

0 5 10 15 20 25 30 35

Supply voltage VCC (V)

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

(V)

OL

Output saturation voltage V

0.85

0.84

0.83

0.82

0.81

VCC = 12 V

= 50 mA

I

O

= 25°C

T

a

3.5

(mA)

CC

3.0

2.5

Total consumption current I

VCC = 12 V
T

= 25°C

a

2.0
4

8 12 16

20

Timing resistance RT (kΩ)

0.80
4 20

8 12 16

Timing resistance RT (kΩ)

7

AN8013SH Voltage Regulators

■ Application Notes

[2] Function descriptions

1. Reference voltage block
The reference voltage block is based on a band gap circuit, and outputs a temperature corrected reference

voltage of 2.5 V. This reference voltage is stabilized once the supply voltage exceeds 3.6 V, and is used as the
power supply for the IC itself.

2. Triangular wave generator
This circuit generates a triangular wave with a peak of about 1.45 V and a trough of about 0.35 V using a timing

capacitor connected to the CT pin (pin 3) and a timing resistor connected to the RT pin (pin 2) respectively. The
oscillator frequency can be set to arbitrary value by selecting appropriate values for the external capacitor and
resistor, C
to the IC.

3. Error amplifier

fier that detects and amplifies the DC-DC converter
output voltage, and inputs that signal to a PWM com­parator.

internal reference voltage. This level is applied to the
noninverting input.

up by inserting a resistor and capacitor in series
between the error amplifier output pin (pin 6) and the
inverting input pin (pin 7).

formula by connecting a resistor divider to the output
as shown in figure 1.

V

4. Timer latch short-circuit protection circuit

against degradation or destruction if an excessive load or a short circuit of the power supply output continues for
longer than a certain fixed period.

output voltage drops and an error amplifier output level exceeds 1.90 V, this circuit outputs a low level and the
timer circuit starts. This starts charging the external protection circuit delay time capacitor.

the latch circuit latches, the output drive transistors are turned off, and the dead-time is set to 100%.

5. Low input voltage malfunction prevention circuit (U.V.L.O.)

power supply voltage falls during power on or power off.

the supply voltage level. While the supply voltage is rising, this circuit cuts off the output drive transistor until the
reference voltage reaches 3.1 V. It also sets the dead-time to 100%, and at the same time holds the S.C.P. pin (pin

4) at the 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.

and RT. The triangular wave signal is provided to the inverting input the PWM comparator internally

T

This circuit is an PNP-transistor input error ampli-

A 0.75 V level is created by resistors dividing the

Arbitrary gain and phase compensation can be set

The output voltage V

OUT

= 0.75 ×

R1 + R2

is given by the following

OUT

R

2

V

OUT

R1

R2

Figure 1. Connection method of error amplifier

FB

6

Internal 2.5 V

NF

R

IN−

NF

C

7

R3

0.75 V

R4

reference voltage

Error amp.

PWM
comparator
input

This circuit protects the external main switching element, flywheel diode, choke coil, and other components

The timer latch short-circuit protection circuit detects the output of the error amplifier. If the DC-DC converter

If the error amplifier output does not return to the normal voltage range before that capacitor reaches 0.75 V,

This circuit protects the system against degradation or destruction due to incorrect control operation when the

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

8

Voltage Regulators AN8013SH

■ Application Notes (continued)

[2] Function descriptions (continued)

6. PWM comparator
The PWM comparator controls the output pulse on-period according to the input voltage. The output transistor

is turned on during periods when the level of the CT pin (pin 3) triangular wave is lower than both of the error
amplifier output (pin 6) and the DTC pin (pin 5) voltage.

The dead-time is set by adding a resistor between the DTC pin and ground.
Additionally, the AN8013SH can provide soft start operation in which the output pulse on-period is gradually

lengthened according to an RC time constant when power is first applied by adding a capacitor in parallel with the
resistor R

7. Overcurrent protection block
Destruction of the main switching device, the flywheel diode, and the choke coil, which are easily damaged

by overcurrents, is prevented by limiting the maximum current that flows in the switching device. This is imple­mented using the fact that power supply output overcurrents are proportional to the current flowing in the main
switching device (a bipolar transistor).

The AN8013SH detects the current by connecting a resistor with a low resistance between the main switching

device and the V
switching device (a bipolar transistor) is on and the CLM pin voltage reaches V
overcurrent detection threshold voltage, the AN8013SH shuts off the output transistor, thus controlling the main
switching device so that currents in excess of the limit cannot occur. While this control operation is repeated at
each period, once an overcurrent is detected the output transistor is turned off for the remainder of that period and
is not turned on again until the next period. This type of overcurrent protection is called pulse-by-pulse overcurrent
protection.

8. Output block
The output drive transistor is of open-collector type output in which transistors are darlington-connected with

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

DTC

.

pin and monitoring the voltage drop across this resistor at the CLM pin (pin 1). When the main

CC

minus 100 mV, which is the

CC

Triangle wave (CT)

Error amplifier output (FB)

Output transistor collector
waveform (Out)

Overcurrent protection input

(CLM)

Overcurrent detection

1

2

Latch set

Latch circuit set signal

Latch circuit reset signal

3

4

Output off

Latch reset

5

On at the next period

T

: Delay time

DLY

Figure 2. Pulse-by-pulse overcurrent protection operating waveforms

1.4 V

0.4 V

High

Low

V

CC

VCC − 100 mV

High

Low

High

Low

9

AN8013SH Voltage Regulators

■ Application Notes (continued)

[3] Triangular wave oscillation circuit

1. Setting the oscillator frequency
The waveform of triangular wave oscillation is obtained by charging and discharging of the constant current

from the external timing capacitor CT which is connected to CT pin (pin 3). The constant current is set by the

I

O

externally attached timing resistor R

The peak value of the wave V

0.35 V typical respectively.
The oscillator frequency f

f

OSC

1

=

t1 + t

=

2

2 × CT × (V

.

T

and the trough value of the wave V

CTH

is obtained by the following formula:

OSC

I

O

− V

CHL

)

CTH

are fixed at about 1.45 V typical and

CTL

V

= 1.4 V typ.

CTH

whereas I

because V

=

f

OSC

2.07 × C

= 1.8 ×

O

CTH

1

− V

T

CTL

× R

V

RT

R

T

= 1.1 V

[Hz]

T

= 1.8 ×

0.59
R

T

t

t

Charging Discharging

2

1

= 0.37 V typ.

V

CTL

T

Figure 3. Triangular wave oscillation waveform

The output frequency f

is equal to f

OUT

since it is PWM-controlled.

OSC

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

as the bias current of the triangular wave

T

generator and the PWM comparator for consumption current reduction. The total consumption current is about 2.4
mA typical when R
constant output current of 100 mA at the open-collector output, it is necessary to set R

is 15 kΩ, and it increases to about 3.4 mA typical when RT is 5.1 kΩ. In order to obtain the

T

value to 15 kΩ or smaller.

T

It is possible to use the circuit in the recommended operating range of 20 kHz to 500 kHz of the oscillator

frequency. As the AN8013SH is used at increasingly higher frequencies, the amount of overshoot and undershoot
due to the operation delay in the triangular wave oscillator comparator increases, and discrepancies between the
values calculated as described previously and the actual values may occur. See the timing capacitance - oscillator
frequency relationship in the "Application Notes, [1] Main characteristics" section of this document.

Note that this IC can not be used as an IC for slave when the several ICs are operated in parallel synchronous

mode.

[4] Setting the dead-time (maximum duty)

The dead-time is set, as shown in figure 4, by setting the DTC pin (pin 5) voltage, V

has a constant current output set with the resistor R
output duty, Du, and the DTC pin voltage, V
frequency of 200 kHz, the output duty will be 0% at V

, V

is adjusted by adding the external resistor R

T

DTC

, are expressed by the following formulas. For an oscillator

DTC

= 0.45 V, and 100% at V

DTC

DTC

is required here, since the amount of overshoot and undershoot in the triangular wave peak (V
(V

) values depends on the oscillator frequency.

CTL

. Since the DTC pin

DTC

= 1.45 V. However, care

) and minimum

CTH

DTC

. The

10

Voltage Regulators AN8013SH

■ Application Notes (continued)

[4] Setting the dead-time (maximum duty) (continued)

CT waveform
DTC

waveform

OUT
waveform

Du

V

t

OFFtON

Off OffOn

t

ON

=

tON + t
V

CTH

=

V

CTH

= I

DTC

× R

DTC

= VRT × [V]

OFF

−V

−V

R

× 100 [%]

DTC

CTL

DTC

DTC

R

T

× 100 [%]

1

×

3.6

V

CTH

V

DTC

V

CTL

V

Example: When f

REF

I

DTC

V

=×[A]

I

DTC

R

CT

RT

T

1

3.6

PWM

FB

DTC

R

DTC

= 200 kHz (RT = 15 kΩ, CT = 150 pF)

OSC

V

≈ 1.45 V (typ.) VRT ≈ 0.59 V (typ.)

CTH

V

≈ 0.35 V (typ.) I

CTL

C

DTC

DTC

Figure 4. Setting the dead-time

Adding the external resistor R

and the capacitor C

DTC

in parallel implements a soft start function that causes

DTC

the output pulse on width to increase gradually when the power supply is started. Use of this function can prevent
DC-DC converter output overshoot.

≈ 11 µA (typ.)

[5] Setting the time constant of the timer latch short-circuit protection circuit

The structural block diagram of protection latch circuit is shown in figure 5. The comparator for short-circuit

protection compares the output of error amplifier V

with the reference voltage of 1.90 V all the time.

FB

When the load conditions of DC-DC converter output are 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. pin is hold to about 30 mV through the clamp circuit.

When the load conditions suddenly change, and high-level signal (1.90 V or higher) is input from the error amplifier
to the non-inverted 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. pin voltage V
externally connected capacitor C

When the external capacitor C

starts charging according to the following equation :

S

has been charged up to about 0.75 V, it sets the latch circuit, cuts off the output drive

S

is released, and the

PE

transistor by enabling the low input voltage malfunction prevention circuit, and sets the dead-time at 100%.

t

[F]

×

CHG

PE

[V]

C

S

t

PE

×

C

S

VPE = V

STBY

+ I

CHG

0.75 V = 0.03 V + I

t

CHG

PE

×

0.72

CS = I

11

AN8013SH Voltage Regulators

■ Application Notes (continued)

[5] Setting the time constant of the timer latch short-circuit protection circuit (continued)

I

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

CHG

temperature are small. I

is expressed in the following equation :

CHO

V

I

=

CHG

VRT is about 0.5 V and I

1

RT

×

[A]

30

R

T

becomes about 1.1 µA at RT = 15 kΩ.

CHO

Once the low input voltage malfunction prevention circuit is enabled, the S.C.P. pin voltage is discharged to about

30 mV but the latch circuit is not reset unless the power is turned off.

I

CHG

FB

IN−

6

7

Error amp.

0.75 V

S.C.P. comp.

1.90 V

Q1

4

S.C.P.

C

S

Q2

0.75 V
S R

Latch

R
U.V.L.O.

PWM comparator input

Output cut-off

Figure 5. Short-circuit protection circuit

V

REF

When the power supply is started, the output appears to be shorted. The error amplifier output goes to the high

state, the S.C.P. pin voltage, V

, is released, and charging starts. The external capacitor value must be set so that DC-

PE

DC converter voltage output starts before the latch circuit in the later stage is set. If the soft start function is used,
special care is required to assure that the start time does not become excessive.

12

Voltage Regulators AN8013SH

■ Application Notes (continued)

[6] Timing chart

VCC (0 V→3.6 V)
rise time

(VCC) ≥ 10 [µs]

t

r

3.1 V typ.
Lock-out

release

Supply voltage (V

Internal reference voltage

Error amplifier output (FB)

)

CC

3.6 V

2.5 V

1.90 V

Power supply on

S.C.P. pin voltage

Output transistor
collector waveform
(Out)

Internal reference voltage

Short-circuit protection input threshold level
Comparator threshold level

Dead-time voltage (VDT)

Error amplifier output (FB)

Triangular wave(CT)

Triangular wave (CT)

DTC pin voltage

1.40 V

0.40 V

0.03 V
High

Low

Soft start operation Maximum duty

Figure 6. PWM comparator operation waveform

2.5 V

1.90 V

1.40 V

0.40 V

Output transistor collector waveform
(Out)

S.C.P. pin voltage

Short-circuit protection comparator
output

Figure 7. Short-circuit protection operation waveform

High

Low

0.75 V

0.03 V

t

PE

High

Low

13

AN8013SH Voltage Regulators

■ Application Circuit Examples

1. Step-down circuit

In

2. Step-up circuit

In

CC10

V

1

CLM

15 kΩ

Out
9

2
RT

SBD

SBD

150 pF

GND
8

3
CT

62 kΩ

11 kΩ

0.01 µF

150 kΩ

IN−
7

4

S.C.P.

0.033 µF

100 kΩ

0.001µF

FB

6

5

DTC

110 kΩ

Out

+5 V

f = 200 kHz
Du
R

Out

+12 V

max

DTC

= 80%

= 110 kΩ

14

CC

V

10

1

CLM

15 kΩ

Out
9

2
RT

150 pF

GND
8

3
CT

10 kΩ

0.01 µF

IN−

7

4

S.C.P.

0.033 µF

100 kΩ

0.001 µF

FB
6

5

DTC

110 kΩ

f = 200 kHz

= 80%

Du

max

= 110 kΩ

R

DTC

Voltage Regulators AN8013SH

■ Application Circuit Examples (continued)

3. On/off circuit example

1) Cutting the power supply line

In

On/off

2) Cutting the IC V

In

On/off

CC

Q2

line

Q2

Q1

Q1

C10

C10

CC

V

10

1

CLM

CC

V

10

Q3

SBD

I

CC

Out

9

2

RT

Q3

SBD

I

CC

Out

9

GND

8

3

CT

GND

8

IN−
7

4

S.C.P.

Standby current ≈ 0 µA

IN−

7

FB

6

5

DTC

FB

6

V

O

V

O

1

CLM

2

RT

3

CT

4

S.C.P.

5

5

DTC

Standby current ≈ 0 µA

4. Usage

Since this IC does not include an on/off circuit, an external circuit must be added to implement a standby function.

If a switch (Q1) is inserted in the power supply line as shown in on/off circuit example 1, the standby current can
be held to 0. In this circuit, a transistor essentially equivalent to the one used for the main switching device (Q3) is
required.

If a switch (Q1) is inserted between the power supply line and the IC V

pin (pin 10) as shown in on/off circuit

CC

example 2, the size of the switching device (Q1) can be reduced. However, the sample-to-sample variations in the Q1
saturation voltage will result in sample-to-sample variations in the overcurrent protection threshold level.

5. Usage Notes

If an external on/off circuit is added, the V

rise time may become excessively steep and the IC internal latch circuit

CC

may be set at that time, causing problems at power supply startup. To avoid such problems, set the value of C10 so that
the V

(pin 10) rise time is at least 10 µs.

CC

15