ZXLD1371Q

ZXLD1371Q

Document number: DS37116 Rev. 1 - 2

35 of 42

www.diodes.com

September 2015

© Diodes Incorporated

ZXLD1371Q

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 (Note 18):

Table 2

Warning/Fault condition

Severity

(Note 19)

Monitored

parameters

FLAG

Nominal STATUS voltage

Normal operation

H

4.5V

Supply undervoltage

1

L

4.5V

2

L

< 3.6V

Output current out of regulation

(Note 20)

2

range

L

3.6V

Driver stalled with switch ‘on’, or ‘off’

(Note 21)

2

L

3.6V

Device temperature above maximum

recommended operating value

3

L

1.8V

specified maximum

4

L

0.9V

Notes:

an overcurrent status may be indicated when operating at high boost ratios -

– this due to the feedback loop increasing the sense voltage.

19. Severity 1 denotes lowest severity.

20. 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.

21. 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).

Figure 15. Status levels

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