ZXLD1370

Document number: DS32165 Rev. 6 - 2

30 of 40

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December 2016

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ZXLD1370

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 off,

but switches low 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 17)

Monitored Parameters

FLAG

Nominal STATUS Voltage

Normal Operation

—

—

H

4.5

Supply Undervoltage

1

L

4.5

2

L

3.6

Output Current Out of Regulation

(Note 18)

2

range

L

3.6

Driver Stalled with

Switch ‘On’, or ‘Off’

(Note 19)

2

L

3.6

Device Temperature Above Maximum

Recommended Operating Value

3

L

1.8

Specified Maximum

4

L

0.9

Notes:

17. Severity 1 denotes lowest severity.

18. 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.

19. This warning will be indicated if the gate pin stays at the same level for greater than 100µs (e.g., the output transistor cannot pass enough current

to reach the upper switching threshold).

VREF

0V

0A

Normal

Operations

SEVERITY

4.5V

3.6V

2.7V

1.8V

0.9V

VAUX

UVLO

- VIN UVLO

- STALL

- OUT of REG

Over

Temperature

Over

Current

0

1

2

3

4

Figure 35 Status Levels

In the event of more than one fault/warning condition occurring, the higher severity condition will take precedence. E.g.,

‘Excessive Coil Current’

and ‘Out of Regulation’ occurring together will produce an output of 0.9V on the STATUS pin.