ICE2A0265 View Datasheet(PDF) - Infineon Technologies

Part Name

Description

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ICE2A0265

Off-Line SMPS Current Mode Controller with integrated 650V/800V CoolMOS™

Infineon Technologies 

CoolSET™-F2

Functional Description

3

Functional Description 3.2 Improved Current Mode

3.1

Power Management

Soft-Start Com parator

VCC

M ain Line (100V-380V)

R Start-Up

C VCC

Prim ary W inding

Power Management

U ndervoltage

Lockout

13.5V

8.5V

Internal

B ia s

P o w er-D ow n

Reset

P o w e r-U p

Reset

V o lta g e

R e fe re n c e

6.5V

5.3V

4.8V

4.0V

S o ftS

6.5V

R Soft-Start

RQ

PW M -Latch

SQ

E rro r-L a tch

Soft-Start Com parator

C Soft-Start

T1

E rro r-D e te c tio n

FB

PW M -Latch

RQ

D riv e r

PW M Com parator

SQ

0.8V

PWM OP

x3.65

Im proved

Current Mode

Isense

Figure 7 Current Mode

Current Mode means that the duty cycle is controlled

by the slope of the primary current. This is done by

comparison the FB signal with the amplified current

sense signal.

Amplified Current Signal

FB

Figure 6 Power Management

The Undervoltage Lockout monitors the external

supply voltage VVCC. In case the IC is inactive the

current consumption is max. 55µA. When the SMPS is

plugged to the main line the current through RStart-up

charges the external Capacitor CVCC. When VVCC

exceeds the on-threshold VCCon=13.5V the internal bias

circuit and the voltage reference are switched on. After

that the internal bandgap generates a reference

voltage VREF=6.5V to supply the internal circuits. To

avoid uncontrolled ringing at switch-on a hysteresis is

implemented which means that switch-off is only after

active mode when Vcc falls below 8.5V.

In case of switch-on a Power Up Reset is done by

resetting the internal error-latch in the protection unit.

When VVCC falls below the off-threshold VCCoff=8.5V the

internal reference is switched off and the Power Down

reset let T1 discharging the soft-start capacitor CSoft-Start

at pin SoftS. Thus it is ensured that at every switch-on

the voltage ramp at pin SoftS starts at zero.

0.8V

Driver

t

Ton

t

Figure 8 Pulse Width Modulation

In case the amplified current sense signal exceeds the

FB signal the on-time Ton of the driver is finished by

resetting the PWM-Latch (see Figure 8).

The primary current is sensed by the external series

resistor RSense inserted in the source of the integrated

CoolMOS™. By means of Current Mode regulation, the

Version 2.0

10

11 Jun 2004

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