2PCS02 datasheet(9/20 Pages) INFINEON

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CCM-PFC

ICE2PCS02/G

Functional Description

Version 2.4

22 Mar 2010

3.4.2

Soft Over Current Control (SOC)

The IC is designed not to support any output power

that corresponds to a voltage lower than -0.75V at the

ISENSE pin. A further increase in the inductor current,

which results in a lower ISENSE voltage, will activate

the Soft Over Current Control (SOC). This is a soft

control as it does not directly switch off the gate drive.

It acts on the nonlinear gain block to result in a reduced

PWM duty cycle.

Figure 8

SOC and PCL Protection as function of

ISENSE

The rated output power with a minimum V

IN (VINMIN) is

Due to the internal parameter tolerance, the maximum

power with V

INMIN is

3.4.3

Peak Current Limit (PCL)

The IC provides a cycle by cycle peak current limitation

(PCL). It is active when the voltage at pin 3 (ISENSE)

reaches -1.04V. This voltage is amplified by OP1 by a

factor of -1.43 and connected to comparator C2 with a

reference voltage of 1.5V as shown in Figure 9. A

deglitcher with 300ns after the comparator improves

noise immunity to the activation of this protection.

Figure 9

Peak Current Limit (PCL)

3.4.4

Open Loop Protection (OLP)

Whenever VSENSE voltage falls below 0.6V, or

equivalently V

OUT falls below 20% of its rated value, it

indicates an open loop condition (i.e. VSENSE pin not

connected) or an insufficient input voltage V

for

normal operation. In this case, most of the blocks within

the IC will be shutdown. It is implemented using

comparator C3 with a threshold of 0.6V as shown in the

IC block diagram in Figure 2.

3.4.5

Over-Voltage Protection (OVP)

Whenever V

OUT exceeds the rated value by 5%, the

over-voltage protection OVP is active as shown in

Figure 6. This is implemented by sensing the voltage at

pin VSENSE with respect to a reference voltage of

3.15V. A VSENSE voltage higher than 3.15V will

immediately reduce the output duty cycle, bypassing

the normal voltage loop control. This results in a lower

input power to reduce the output voltage V

OUT. A

VSENSE voltage higher than 3.25V will immediately

turn off the gate, thereby preventing damage to bus

capacitor.

3.5

Fixed Switching Frequency

ICE2PCS02/G

has

internally

fixed

switching

frequency as opposed to the ICE2PCS01/G which can

be externally set. This frequency is trimmed to 65kHz

with an accuracy ±5% at 25

oC.

ISENSE

-0.61V -0.75V

-1.04V

Normal

Operation

SOC

PCL

OUT(rated)

IC’s

State

OUT(max)

OUT r a t e d

(

)

IN MIN

0.61

-------------------

OUT m a x

(

)

INMIN

0.75

-------------------

ISENSE

ICE2PCS02/G

INDUCTOR

OP1

1.43x

Current Limit

300ns

Deglitcher

Turn Off

Driver

1.5V

Full-wave

Rectifier

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