IN-PLUG

© Copyright 2005-2007 - ASIC Advantage, Inc. – All rights reserved

- Revision 11 – April 02, 2007

3 / 18

FUNCTIONAL BLOCK DIAGRAM

Figure 3

PIN DESCRIPTION

Number

Name

Description

1GND

Ground pin. This pin must be connected to the general ground.

2IS

Inductor current sensing pin.

This pin is used to measure the current flowing through the inductor which is forced to be

proportional to the instant AC line voltage. The power MOSFET is automatically driven in

a self-oscillating mode to restart a new cycle when the current in the inductor has dropped

below half of its peak value.

3

GDRIVE

MOSFET gate drive pin.

The internal buffer connected to this pin can drive a broad variety of power MOSFETs

and IGBTs. A series resistor is sometimes added to improve the EMI signature.

4VLINE

AC voltage pin.

This pin is used to sense the instantaneous AC line voltage through a series resistor that

performs a voltage to current conversion. This forces the peak current in the inductor to be

proportional to the instant AC line voltage.

5

VCC

IC supply pin.

The circuit contains a shunt regulator that behaves like a 10V zener. During start-up the IC

draws very little current. Operations start when the “zener” value is reached and stop should

the VCC voltage becomes less than approximately 8V.

6

LEDSENSE

LED voltage feedback input pin.

Negative feedback of the voltage error amplifier which positive input is internally

connected to a 0.50V trimmed reference. It is used to regulate the voltage across the storage

output capacitor to a value slightly above the maximum line peak voltage.

7COMP

Voltage loop compensation pin.

This output of the voltage error amplifier is used for loop feedback compensation

purposes.

8

BYPASS

Constant loop gain capacitor pin.

The bypass capacitor connected between this pin & GND helps maintain the loop gain

constant at different line voltages thus preventing loop instabilities which could occur with

other arrangements.

REF

LEDSNS

BYPASS

GND

GDRV

IS

IPS401

BANDGAP

REGULATOR

TRIMMED

VCC

VLINE

COMP

3

5

_

+

VOLTAGE

ERROR

AMPLIFIER

2

4

1

6

78

&

INTERNAL

BIAS

INT. BIA S

_

+

_

+

VO FF

VO N

CONTROL

LOGIC

DRIVER

ON

OFF

2.14V

V to I

LINE

CURRENT

SENSE