Diodes AP4312 User Manual

AP4312

Document number: DS36797 Rev. 1 - 2

1 of 11

www.diodes.com

January 2014

AP4312

A Product Line of

Diodes Incorporated

Description

The AP4312 is a highly integrated solution for a constant voltage/constant current mode SMPS application.

The AP4312 contains one 1.21V voltage reference, one low voltage reference used in current sensing circuit and two operational amplifiers. The 1.21V voltage reference, combined with one operational amplifier, makes of an ideal voltage controller for use in adapters and battery chargers. The low voltage reference, combined with another operational amplifier, makes of an ideal current limiter for output low side current sensing.

The AP4312 is fully compatible with AP4306 in functionality and electrical characteristics except its lower reference voltage for current control loop, thus higher power efficiency in SMPS applications such as low power charger can be realized with AP4312 compared to AP4306.

The AP4312 is available in SOT26 package.

Features

 Constant Voltage and Constant Current Control  Precision Internal Voltage Reference  Low External Component Count  Easy Compensation  Low Supply Current: 180A  Current Control Loop Reference: 70mV  Operating Supply Voltage: 1.7V to 18V

 Totally Lead-free & Fully RoHS Compliant (Note 1 & 2)  Halogen and Antimony Free. “Green” Device (Note 3)

Pin Assignments

(Top View)

1

2

3 4

5

Pin 1 Mark

6

V

SENSE

GND

V

CTRL

I

CTRL

V

OUT

V

CC

SOT26 (K6 Package)

Applications

 Adapters  Battery Chargers

CONSTANT VOLTAGE AND CONSTANT CURRENT CONTROLLER

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.

3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds.

AP4312

Document number: DS36797 Rev. 1 - 2

2 of 11

www.diodes.com

January 2014

AP4312

A Product Line of

Diodes Incorporated

1.210V

V

CC

V

OUT

GND

V

SENSE

I

CTRL

R

SS

R4

To

primary

R2

R1

V

OUT

+

V

OUT

-

Load

C1

R3

C3

R5

R6 500

V

CTRL

AP4312

+

I

L

)(

1

21

)]([

SSLSSLREF

UT

O

RI

R

RR

RIVV 





SS

SENSE

R

V

itCurrentLim 

1.210V

V

CC

V

OUT

GND

V

SENSE

I

CTRL

R

SS

R4

To

primary

R2

R1

V

OUT

+

V

OUT

-

Load

C1

R3

C3

R5

R6

500

V

CTRL

AP4312

+

I

L

121R

RR

VV

REFOUT





SS

SENSE

R

V

itCurrentLim 

Typical Applications Circuit

Typical Application 1

Typical Application 2

AP4312

Document number: DS36797 Rev. 1 - 2

3 of 11

www.diodes.com

January 2014

AP4312

A Product Line of

Diodes Incorporated

Pin Number

Pin Name

Function

1

V

CTRL

Input pin of the voltage control loop

2

GND

Ground 3 V

OUT

Output pin. Sinking current only

4

I

CTRL

Input pin of the current control loop

5

V

SENSE

Input pin of the current control loop

6

VCC

Power Supply

)(

1

21

SSLREFOUT

RI

R

RR

VV 





 

SSREFSENSE

REFSENSE

RVV

VV

itCurrentLim







1.210V

V

CC

V

OUT

GND

V

SENSE

I

CTRL

R

SS

R4

To

primary

R2

R1

V

OUT

+

V

OUT

-

Load

C1

R3

C3

R5

R6

500

V

CTRL

AP4312

+

I

L

Typical Applications Circuit (Cont.)

Typical Application 3

Pin Descriptions

AP4312

Document number: DS36797 Rev. 1 - 2

4 of 11

www.diodes.com

January 2014

AP4312

A Product Line of

Diodes Incorporated

V

CC

V

OUT

V

CTRL

GND

V

SENSE

I

CTRL

4

5

2

1

3

6

1.210V

Symbol

Parameter

Rating

Unit

VCC

Power Supply Voltage

20

V

VIN

Input Voltage

-0.3 to VCC

V

TJ

Junction Temperature

+150

C

T

STG

Storage Temperature

-65 to +150

C

T

LEAD

Lead Temperature (Soldering, 5sec)

+260

C

θ

JA

Thermal Resistance (Junction to Ambient)

250

C/W

Symbol

Parameter

Min

Max

Unit

VCC

Power Supply Voltage

1.7

18

V

Functional Block Diagram

Absolute Maximum Ratings (Note 4)

Note 4: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.

Recommended Operating Conditions