No

Yes

Variable

Resonant

Quasi-

Resonant

EMI

Troubling?

Need higher

efficiency?

Operating

Mode

No

Yes

Do you

need low

Standby

power?

Low End

High End

Please visit our website at www.onsemi.com for additional options.

What

features

do you

need?

No

Yes

Is Your Input

Power Above

25 W?

Key Features & Benefits

Page 5

ON Semiconductor

NCP1271

+

−

AC

Input

Output

Voltage

Latch

Input

EMI

Filter

skip/latch

FB

CS

Gnd

HV

Drv

Decoupling

Capacitors

Adjust

Skip

Level

Latch Protection

Compensation

Ramp

HV Pin Handles Up to

500 V Directly

Primary Current Limitation

Current-Mode Operation

HV Pin

Protection

Fixed Frequency Controllers

Low Cost and Low Power Consumption. . .

Fixed frequency controllers from ON Semiconductor are the perfect solution for many applications. DVD

players, set-top boxes, notebook power adapters, printers, scanners, LCD monitors, and a wealth of other end

products use our controllers. Extremely low standby power helps you easily meet applicable regulations. The

Dynamic Self-Supply (DSS) feature of our devices saves cost by avoiding the use of an auxiliary transformer

winding, and current-mode topologies give tighter control of output voltage. Our fixed frequency controllers

can help you meet your toughest design challenges while still keeping cost to a minimum.

~

Dynamic Self Supply (DSS) capability

i

No auxiliary transformer winding

~

Current-mode control with adjustable skip-cycle and Soft-

Skip™capability

i

Provides excellent efficiency at light loads

i

No acoustic noise generation

~

Fixed frequencies up to 200 kHz

i

Offers suitable solution for all applications

~

High-voltage start-up-current source

i

Clean loss less start-up sequence

~

Frequency jittering

i

Reduces EMI signature

~

Go-to-standby for PFC front stage

i

Minimizes standby losses

~

Internal short–circuit protection independent of auxiliary voltage

i

Reliable short-circuit protection, immediately reducing the

output power

~

Under-voltage lockout at 7.6 V typical

i

Suitable for applications already using UC3843

NCP1271 Typical Schematic for Fixed Frequency Controller with Soft-Skip™

FIXED

FREQUENCY

CONTROLLERS

Device

Max

Output

Power

(W)

Mode

Standby

Power

Method

Output

Gate Drive

(mA) @

Frequency

Options

(kHz)

Package(s)

NCP1200

Adj Skip

250

40,60,100

4

4

EXT

4

SO-8, PDIP-8

NCP1201

150

Current

Adj Skip

250

60,100

4

4

4

EXT

4

4

SO-8, PDIP-8

NCP1203

150

Current

Adj Skip

250

40,60,100

4

4

EXT

4

SO-8, PDIP-8

Adj Skip

500

65,100,133

4

4

4

4

INT

4

SO-8, PDIP-7

150

Current

Adj Skip

500

65,100,133

4

4

4

4

INT

4

SO-7, PDIP-7

NCP1212

150

Current

Adj Skip

500

Adj Up to 150

4

EXT

4

SO-8, PDIP-8

NCP1230

150

Current

Adj Skip

500

65,100,133

4

4

4

4

4

INT

SO-8, PDIP-8

NCP1271

150

Current

500

65,100

4

4

4

INT

4

4

SO-7

NCP1282/1562*

400

Voltage

Skip Cycle

200

Adj Up to 1000

4

*

4

4

4

4

EXT

4

SO-16

1. Maximum power output with DSS 2. “A” Versions Have a 50% Max Duty Cycle for Forward Topologies 3. Only Available on “A” Versions 4. Overvoltage Protection 5. Transient Load Detection * NCP1562 has 100 V startup FET

NCP1271

Demo Board