ACT361US-T datasheet(6/13 Pages) ACTIVE-SEMI

Part #	ACT361US-T

Description	High Performance ActivePSR Primary Switching Regulator

Download	13 Pages

Scroll/Zoom	100%

Manufacturer	ACTIVE-SEMI [Active-Semi, Inc]

Direct Link	http://www.active-semi.com

Logo

6 / 13 page

ACT361

Rev 8, 14-Nov-12

Innovative Power

TM

- 6 -

www.active-semi.com

in a constant secondary side output current profile.

The energy transferred to the output during each

switching cycle is ½(LP × ILIM

2) × η, where LP is the

transformer primary inductance, ILIM is the primary

peak current, and η is the conversion efficiency.

From this formula, the constant output current can

be derived:

where fSW is the switching frequency and VOUTCV is

the nominal secondary output voltage.

The constant current operation typically extends

down to lower than 40% of nominal output voltage

regulation.

Primary Inductance Compensation

The ACT361 integrates a built-in proprietary

(patent-pending) primary inductance compensation

circuit to maintain constant current regulation

despite variations in transformer manufacturing.

The compensated range is ±7%.

Primary Inductor Current Limit Compensation

The ACT361 integrates a primary inductor peak

current limit compensation circuit to achieve

constant input power over line and load ranges.

Protection

The ACT361 incorporates multiple protection

functions including over-voltage, over-current and

over-temperature.

Output Short Circuit Protection

When the secondary side output is short circuited,

the ACT361 enters hiccup mode operation. In this

condition, the VDD voltage drops below the VDDOFF

threshold

and

the

auxiliary

supply

voltage

collapses. This turns off the ACT361 and causes it

to restart. This hiccup behavior continues until the

short circuit is removed.

Output Over Voltage Protection

The

ACT361

includes

output

over-voltage

protection circuitry, which shuts down the IC when

the output voltage is 40% above the normal

regulation voltage for 4 consecutive switching

cycles. The ACT361 enters hiccup mode when an

output over voltage fault is detected.

Over Temperature Shutdown

The thermal shutdown circuitry detects the ACT361

die temperature. The typical over temperature

threshold is 135°C with 20°C hysteresis. When the

die temperature rises above this threshold the

ACT361 is disabled until the die temperature falls

by 20°C, at which point the ACT361 is re-enabled.

TYPICAL APPLICATION

Design Example

The design example below gives the procedure for

a DCM flyback converter using the ACT361. Refer

to Application Circuit in Figure 6, the design for a

charger application starts with the following

specification:

The operation for the circuit shown in Figure 6 is as

follows: the rectifier bridge D1−D4 and the capacitor

C1/C2 convert the AC line voltage to DC. This

voltage supplies the primary winding of the

transformer T1 and the startup resistor R1/R2. The

primary power current path is formed by the

transformer’s primary winding, the NPN transistor,

the ACT361 internal MOSFET and the current

sense resistor R7. The network consisting of

capacitor C3 and diode D5 provides a VDD supply

voltage for ACT361 from the auxiliary winding of the

transformer. C3 is the decoupling capacitor of the

supply voltage and energy storage component for

startup. The diode D7 and the capacitor C7 rectifies

and filters the output voltage. The resistor divider

consisting of R8 and R9 programs the output

voltage.

The minimum and maximum DC input voltages can

be calculated:

FUNCTIONAL DESCRIPTION CONT’D

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛ ×

×

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

×

=

OUTCV

SW

2

CS

P

OUTCC

V

f

R

9

.

0

V

396

.

0

L

2

1

I

η

(2)

V

90

F

μ

7

.

4

2

%

70

)

ms

5

.

3

50

2

1

(

5

.

3

2

85

2

C

)

t

f

2

1

(

P

2

V

2

V

2

IN

C

L

OUT

2

ACMIN

INDCMIN

≈

×

−

×

−

×

=

×

−

=

η

(3)

V

375

265

2

V

2

V

ACMAX

INDCMAX

=

×

=

×

=

(4)

Input Voltage Range

85VAC - 265VAC, 50/60Hz

Output Power, PO

3.5W

Output Voltage, VOUTCV

5.0V

OCP Current, IOUTMAX

0.9A

Full Load Current, IOUTFL

0.7A

Transformer Efficiency,

ηxfm

0.9

System Efficiency CC,

ηsystem

0.69

System Efficiency CV,

η

0.7

Similar Part No. - ACT361US-T

Manufacturer	Part #	Datasheet	Description
Active-Semi, Inc	ACT361US-T	83Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT361US-T	330Kb / 14P	High Performance ActivePSRTM Primary Switching Regulator Rev 8, 14-Nov-12
	ACT361US-T	330Kb / 13P	High Performance ActivePSRTM Primary Switching Regulator Rev 8, 14-Nov-12

More results

Similar Description - ACT361US-T

Manufacturer	Part #	Datasheet	Description
Active-Semi, Inc	ACT361	83Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT364	114Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT365	134Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT364	274Kb / 11P	High Performance ActivePSR Primary Switching Regulator Rev 4, 14-Nov-12
	ACT334	103Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT337	402Kb / 11P	High Performance ActivePSR Primary Switching Regulator Rev 2, 14-Nov-12
	ACT336	108Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT337	149Kb / 3P	High Performance ActivePSR??Primary Switching Regulator 15-Apr-11
	ACT334	287Kb / 11P	High Performance ActivePSR Primary Switching Regulator Rev 2, 14-Nov-12
	ACT365	266Kb / 11P	High Performance ActivePSR Primary Switching Regulator Rev 1, 14-Nov-12

More results

ACT361US-T Datasheet(PDF) 6 Page - Active-Semi, Inc

ACT361US-T Datasheet(HTML) 6 Page - Active-Semi, Inc

Similar Part No. - ACT361US-T

Similar Description - ACT361US-T

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13

Datasheet Download

Link URL