Panasonic AN8026 Datasheet

Voltage Regulators

AN8026

Self-excited RCC pseudo-resonance type
AC-DC switching power supply control IC

23.3±0.3

2.4±0.25

6.0±0.3

9
8
7
6
5
4
3
2

1

0.3

SIP009-P-0000C

■ Overview

The AN8026 is an IC developed for controlling the
self-excited switching power supply employing the RCC
pseudo-resonance type control method.

It is compact, equipped only with the necessary mini­mum functions.

The maximum on-period and the minimum off-pe­riod can be set separately by using the external capacitor
and resistor respectively.

It is suitable for the power supply of AV equipment.

■ Features

• Operating supply voltage range:

Stop voltage (8.6 V typical) to 34 V

• Output block employs the totem pole system.

• Power MOSFET can be directly driven.
(output peak current: ±1 A maximum)

• Small pre-start operating current (80 µA typical) allows using a small size start resistor.

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

• Incorporating protection circuit against malfunction at low voltage (start/stop: 14.9 V/8.6 V)

• Built-in overvoltage protection function (externally resettable)

• Equipped with frequency (VF) control function.

• 9-pin single inline package expands the freedom of board design.

+0.1
–0.05

3.3±0.25

0.5±0.1

2.54

1.5±0.25

1.5±0.25

3.0±0.3

Unit: mm

30°

1.4±0.3

■ Applications

• Televisions, facsimiles, printers, scanners, video equipment

■ Block Diagram

OVP

FB

TDL

U.V.L.O.

8.6V1.5

8

9

1

Low-side

clamp

0 V

Signal

V

V

REF

(7.1 V)

High-side

clamp

2.8 V

2

TOFF

CC

V

7

Switch
diode

0.1 V

0.7 V

I

FB

Current source

3

TON

0.7 V

Q
RS

latch
R

S

Q

CLM

6

IN
IN

V

OUT

5

GND

4

CLM

1

AN8026 Voltage Regulators

■ Pin Descriptions

Pin No. Symbol Description

1 TDL Transformer reset detection
2 TOFF Pin for connecting C and R to set minimum off-period
3 TON Pin for connecting C to set minimum on-period
4 CLM Input pin for overcurrent protection detection
5 GND Grounding pin
6V

OUT

7VCCPower supply voltage pin
8 OVP Input pin for overvoltage protection circuit
9 FB Photocoupler connection pin for error voltage feedback

■ Absolute Maximum Ratings

Parameter Symbol Rating Unit

Supply voltage V
Peak output current I
Power dissipation P
Operating ambient temperature
Storage temperature

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

*

Output pin

*

CC

6PEAK

D

T

opr

T

stg

35 V
±1A

874 mW

−30 to +85 °C

−55 to +150 °C

■ Recommended Operating Range

Parameter Symbol Range Unit

Supply voltage V

CC

■ Electrical Characteristics at VCC = 18 V, Ta = 25°C

Parameter Symbol Conditions Min Typ Max Unit

U.V.L.O. start supply voltage V
U.V.L.O. operation stop supply voltage V
U.V.L.O. start-to-stop supply voltage ∆V
OVP operation threshold voltage V
OVP operation threshold current I
OVP release voltage V
OVP operating circuit current 1 I
OVP operating circuit current 2 I
TDL threshold voltage V
TDL upper limit clamp voltage V
TDL lower limit clamp voltage V
CLM threshold voltage V

7START

7STOP

7

8OVP

8OVP

7OVP

7OVP1VCC

7OVP2VCC

1TDL

1TDL/H ITDL

1TDL/L ITDL

4CLM

= 10 V, V
= 20 V, V

= 3mA 2 2.8 3.6 V
= −3mA − 0.3 0 0.3 V

From stop voltage to 34 V

13.4 14.9 16.4 V

7.7 8.6 9.5 V

5.7 6.3 6.9 V

6.7 7.9 9.1 V

0.5 0.75 1 mA

7.4 8.2 9 V

= 9.1 V 0.66 0.89 1.12 mA

OVP

= 9.1 V 3.5 4.7 5.9 mA

OVP

0.5 0.7 0.9 V

0.7 0.75 0.8 V

2

Voltage Regulators AN8026

■ Electrical Characteristics at VCC = 18 V, Ta = 25°C (continued)

Parameter Symbol Conditions Min Typ Max Unit

TON maximum on-period current I

TON upper limit voltage V
TON lower limit voltage V
TOFF upper limit voltage V
TOFF lower limit voltage V
Output oscillation frequency f

Output current feedback current gain G
Pre-start low-level output voltage V
Low-level output voltage 1 V
Low-level output voltage 2 V
High-level output voltage 1 V
High-level output voltage 2 V
Pre-start circuit current I
Circuit current 1 I

Circuit current 2 I

7OPR(1)VCC

7OPR(2)VCC

TDL flowing-out current I

3TON/H

3TON/L

2TOFF/H

2TOFF/L

FB terminal = open −125 −100 −75 µA

3TON

TON terminal = GND
FB terminal = open 0.55 0.7 0.8 V
FB terminal = open − 0.1 0.05 0.2 V

0.7 0.9 1.1 V

− 0.1 0.05 0.2 V

CON = 2 200 pF, R

OSC

C

OFF

IFBIFB

6STB/LVCC

6L(1)IOUT

6L(2)IOUT

6H(1)IOUT

6H(2)IOUT

7STBVCC

= 1 000 pF

= −1 mA 5.25 7 8.75 

= 10 V, I
= 10 mA  0.9 2 V
= 100 mA  1.1 2.2 V
= −10 mA 15.7 16.5  V
= −100 mA 15.5 16.3  V
= 12 V 40 80 120 µA

= 1.5 kΩ 50 60 70 kHz

OFF

= 10 mA  1 1.25 V

OUT

= 18 V 7.4 9.5 11.6 mA
TON terminal = GND
FB terminal = open

= 34 V 7.8 10 12.2 mA
TON terminal = GND
FB terminal = open

V

1TDL

= 0.3 V −28 −20 µA

TDL

■ Terminal Equivalent Circuits

Pin No. Equivalent circuit Description I/O

1 TDL: I

2 TOFF: 

V

REF

1

High-

Low-

side

clamp

side

clamp

Transformer reset detection terminal.
When the transformer reset is detected and low is
inputted into the terminal, the output of the IC
(V

) becomes high. However, low-level sig-

OUT

nal under the minimum off-period determined
by the T

is ignored.

OFF

Terminal for connecting the resistor and capaci-

V

CC

tor for determining the minimum off-period (low)
of the IC output (V

OUT

).

An equation for approximate calculation of the

Comp.

0.1 V

2

minimum off-period (T

T

= 2.2 × C × R

OFF

) is as follows:

OFF

C: external capacitance
R: external resistance

3

AN8026 Voltage Regulators

■ Terminal Equivalent Circuits (continued)

Pin No. Equivalent circuit Description I/O

3 TON: 

V

REF

Comp.

0.7 V

4 CLM: I

Comp.

(+)

V

CC

Terminal for connecting the capacitor for deter­mining the maximum on-period (high) of the IC
output (V

). An equation for approximate

OUT

calculation of the maximum on-period (TON) is
as follows:

FB

3

T

= 6 500 × C

ON

C: External capacitance

Input terminal for detection of the pulse-by­pulse overcurrent protection.
Normally, it is recommended that a filter be
attached externally.

4

5 GND: 

5

6V

V

CC

Grounding terminal.

:O

OUT

Output terminal for directly driving the power
MOSFET.
It uses the totem pole type output.

6

The maximum rating of the output current:

Peak: ±1 A
DC: ±150 mA

7V

: 

CC

Terminal for applying power supply voltage.

7

It monitors the supply voltage and has the op­eration threshold of start/stop/OVP reset.

8 OVP: I

When overvoltage of the power supply output is
detected and high is inputted to the terminal, it

8

Comp.

turns off the internal circuit. At the same time, it
holds that condition (latch).
To reset the OVP latch, the terminal voltage should
be decreased to low, or the VCC should be decreased
to a voltage lower than the release voltage.

9 FB: I

V

CC

Terminal for connecting the photocoupler for
error voltage feedback of the power supply out­put.
It is possible to cancel about 150 µA of the dark

TON

9

current of photocoupler.

4