11/16

STA550

Figure 4. Power Protection Block Diagram

In fig. 4 there is the power protection strategy pictures. Under the curve of the 25W power, the chip is in normal

operation, over 48W the chip is forced in Standby. This last status would be reached if the digital converter does

not respond quikly enough reducing the stress to less than 48W.

The fig.5 gives the protection current, Iprot, behavior. The current sourced by the pin Prot follows the formula:

Independently of the output voltage, the chip is also shut down in the folowing conditions:

When the average junction temperature of the chip reaches 150°C.

When the ground potential differ from more than 5V from the half of the power supply voltage, ((CD+)-(CD-))/2

The output bridge is muted when the average junction temperature reaches 130°C.

X

V/I

ILOAD

I_PD

MULTIPLIER

ILIM

CURRENT COMP

CURRENT COMP

OC1

PDP1

IPROT

TO TURN-ON/OFF

SEQUENCE

TO TURN-ON/OFF

SEQUENCE

TO PROT PAD

D01AU1266

IPDP

IPDA

IPD

IPD

V/I

OPA

OUT1-

OUT1+

OPA

CD-

CD+

CD+1

I

pr ot

P

d

P

–

(

510

4

–

⋅⋅

1.25V

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