Si9114A

Vishay Siliconix

Document Number: 70025

S-42044—Rev. E, 15-Nov-04

www.vishay.com

1

High-Frequency Switchmode Controller

FEATURES

D 15- to 200-V Input Range

D Current-Mode Control

D Internal Start-Up Circuit

D Latched SHUTDOWN

D Soft-Start

D 1.8-MHz Error Amp

DESCRIPTION

The Si9114A is a BiC/DMOS current-mode pulse width

modulation (PWM) controller IC for high-frequency dc/dc

converters. Single-ended topologies (forward and flyback) can

be implemented at frequencies up to 1 MHz. The oscillator has

an internal divide-by-two that limits the duty ratio to 50%. An

oscillator sync output allows converters to be synchronized in

phase as well as in frequency, in a master/slave configuration.

The output inverter can typically source 500 mA and sink

700 mA. Shoot-through current is all but eliminated to minimize

supply current requirements.

The high-voltage DMOS transistor allows the IC to interface

directly to bus voltages up to 200 V. Other features include a

1.5% accurate voltage reference, 1.8-MHz (min) bandwidth

error amplifier, shutdown logic control, soft-start and

undervoltage lockout circuits.

The Si9114A is available in both standard and lead (Pb)-free

14-pin plastic DIP and SOIC packages, and is specified over

the industrial, D suffix (−40_C to 85_C) temperature range.

FUNCTIONAL BLOCK DIAGRAM

R

+

−

−

+

+

−

+

−

+

−

FB

COMPENSATION

OSC

2 V

Ref

Gen

R

S

Q

1.25 V

Undervoltage

0.2 V

9.2 V

SS

Error

Amplifier

4.6 V

20 mA

Lockout

CURRENT

SENSE

SHUTDOWN

S

Q

NI

OSC

Out

Enable

SYNC

+ −

+

−

4

3

7

14

1

12

11

2

5

6

13

10

8

9

20 mA

Substrate

B 2

DRIVER

OUTPUT