2PCS02 datasheet(7/20 Pages) INFINEON

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CCM-PFC

ICE2PCS02/G

Functional Description

Version 2.4

22 Mar 2010

3.1

General

The ICE2PCS02/G is a 8 pin control IC for power factor

correction converters. It comes in both DIP and DSO

packages and is suitable for wide range line input

applications from 85 to 265 VAC. The IC supports

converters in boost topology and it operates in

continuous conduction mode (CCM) with average

current control.

It is a design derivative from the ICE2PCS01/G with the

differences in the supporting functions, namely the

input brown-out detection and internal fixed switching

frequency 65kHz.

The IC operates with a cascaded control; the inner

current loop and the outer voltage loop. The inner

current loop of the IC controls the sinusoidal profile for

the average input current. It uses the dependency of

the PWM duty cycle on the line input voltage to

determine the corresponding input current. This means

the average input current follows the input voltage as

long as the device operates in CCM. Under light load

condition, depending on the choke inductance, the

system may enter into discontinuous conduction mode

(DCM) resulting in a higher harmonics but still meeting

the Class D requirement of IEC 1000-3-2.

The outer voltage loop controls the output bus voltage.

Depending on the load condition, OTA1 establishes an

appropriate voltage at VCOMP pin which controls the

amplitude of the average input current.

The IC is equipped with various protection features to

ensure safe operating condition for both the system

and device.

3.2

Power Supply

An internal under voltage lockout (UVLO) block

monitors the VCC power supply. As soon as it exceeds

11.8V and both voltages at pin 6 (VSENSE) >0.6V and

pin 4 (VINS) >1.5V, the IC begins operating its gate

drive and performs its Startup as shown in Figure 3.

Figure 3

State of Operation respect to VCC

If VCC drops below 11V, the IC is off. The IC will then

be consuming typically 300

mA, whereas consuming

10mA during normal operation.

The IC can be turned off and forced into standby mode

by pulling down the voltage at pin 6 (VSENSE) to lower

than

0.6V.

this

standby

mode,

the

current

consumption is reduced to 300

mA. Other condition that

can result in the standby mode is when a Brown-out

condition occurs, ie pin 4 (VINS) <0.71V.

3.3

Start-up

Figure 4 shows the operation of voltage loop’s OTA1

during startup. The VCOMP pin is pull internally to

ground via switch S1 during UVLO and other fault

conditions (see later section on “System Protection”).

During power up when V

OUT is less than 83% of the

rated level, OTA1 sources an output current, maximum

mA into the compensation network at pin 5 (VCOMP)

causing the voltage at this pin to rise linearly. This

results in a controlled linear increase of the input

current from 0A thus reducing the stress on the

external component.

Figure 4

Startup Circuit

As V

OUT has not reached within 5% from the rated

value, VCOMP voltage is level-shifted by the window

detect block as shown in Figure 5, to ensure there is

fast boost up output voltage.

When V

OUT

approaches its rated value, OTA1’s

sourcing current drops and so does the level shift of the

window detect block is removed. The normal voltage

loop then takes control.

VSENSE > 0.6 V)

AND (V

VINS > 1.5 V)

11.8 V

11.0 V

OFF

Start

Open loop/

Standby

Normal

Operation

IC's

State

OFF

Normal

Operation

VSENSE < 0.6 V)

OR (V

VINS < 0.8 V)

VSENSE > 0.6 V)

AND (V

VINS > 1.5 V)

VCOMP

VSENSE

OTA1

ICE2PCS02/G

protect

R3 + R4

x V

OUT )

(

Functional Description

2PCS02 Datasheet(PDF) 7 Page - Infineon Technologies AG

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