LT1246 Ver la hoja de datos (PDF) - Linear Technology

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componentes Descripción

Fabricante

LT1246

1MHz Off-Line Current Mode PWM and DC/DC Converter

Linear Technology 

LT1246/LT1247

TYPICAL APPLICATI S

External Clock Synchronization

VREF

8

RT

EXTERNAL

SYNC

INPUT

0.01µF

RT/CT

4

CT

5V REF

OSCILLATOR

47Ω

D1 D1 IS REQUIRED IF THE SYNC AMPLITUDE IS

LARGE ENOUGH TO PULL THE BOTTOM OF CT

MORE THAN 300mV BELOW GROUND.

LT1246 • TA05

VREF

8

R COMP

1

C

FEEDBACK

2

ISENSE

3

–

+

2.5V

Soft Start

5V REF

5.6V

1V

1mA

2R

–

R

+

+

1.5V

–

VREF

8

RT/CT

4

R2 100k COMP

1

FEEDBACK

2

–

C R1

+

2.5V

10

( VCLAMP ≈

1.67

R2

R1

+1

Adjustable Clamp Level with Soft Start

LT1246 • TA06

REFERENCE ENABLE

5V REF

UV

MAIN BIAS

LOCKOUT

REFERENCE PULLDOWN

VCC

OUTPUT

7

PULLDOWN

OSCILLATOR

5.6V

1V

1mA

2R

–

R

+

S

R

BLANKING

+

1.5V

–

OUTPUT

6

18V

GND

5

ISENSE

3

IPK (MAX) ≈

VCLAMP

RS

WHERE: O ≤ VCLAMP ≤ 1.0V

tSOFT START = – ln

1–

VC

3 • VCLAMP

R1 R2

C

R1 + R2

VIN

RS

LT1246 • TA07

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