ZXLD1374

ZXLD1374

Document number: DS35032 Rev. 1 - 2

Page 27 of 35

www.diodes.com

October 2010

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A Product Line of

Diodes Incorporated

Over-Temperature Shutdown

The ZXLD1374 incorporates an over-temperature shutdown circuit to protect against damage caused by excessive die

temperature. A warning signal is generated on the STATUS output when die temperature exceeds 125°C nominal and the

output is disabled when die temperature exceeds 150°C nominal. Normal operation resumes when the device cools back

down to 125°C.

FLAG/STATUS Outputs

The FLAG/STATUS outputs provide a warning of extreme operating or fault conditions. FLAG is an open-drain logic output,

which is normally high resistance, but switches low resistance to indicate that a warning, or fault condition exists. STATUS is

a DAC output, which is normally high (4.5V), but switches to a lower voltage to indicate the nature of the warning/fault.

Conditions monitored, the method of detection and the nominal STATUS output voltage are given in the following table:

Table 2

Warning/Fault condition

Severity

(Note 10)

Monitored

parameters

FLAG

Nominal STATUS voltage

Normal operation

H

4.5

Supply under-voltage

1

L

4.5

2

L

3.6

Output current out of regulation

(Note 11)

2

voltage range

L

3.6

Driver stalled with switch ‘on’, or

‘off’ (Note 12)

2

L

3.6

Switch over-voltage

3

LX voltage > 60V

L

2.7

Device temperature above

maximum recommended

operating value

4

L

1.8

specified maximum

5

L

0.9

Average switch current greater

than 1.5A

5

L

0.9

Notes:

10. Severity 1 denotes lowest severity.

11. This warning will be indicated if the output power demand is higher than the available input power; the loop may not be able

to maintain regulation.

12. This warning will be indicated if the LX pin stays at the same level for greater than 100us (e.g. the internal transistor cannot

pass enough current to reach the upper switching threshold).