Zxld1371, Applications information – Diodes ZXLD1371 User Manual
Page 36
ZXLD1371
ZXLD1371
Document number: DS35436 Rev. 1 - 2
36 of 42
February 2012
© Diodes Incorporated
A Product Line of
Diodes Incorporated
Applications Information
(cont.)
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 15):
Table 2
Warning/Fault condition
Severity
(Note 16)
Monitored
parameters
FLAG
Nominal STATUS voltage
Normal operation
H 4.5V
Supply under-voltage
1
V
AUX
< 5.0V
L 4.5V
2
V
IN
< 5.6V
L <
3.6V
Output current out of regulation
(Note 17)
2
V
SHP
outside normal
voltage range
L 3.6V
Driver stalled with switch ‘on’, or
‘off’ (Note 18)
2
t
ON
, or t
OFF
> 100µs
L 3.6V
Device temperature above
maximum recommended
operating value
3
T
J
> 125°C
L 1.8V
Sense resistor current I
RS
above
specified maximum
4
V
SENSE
> 0.3V
L 0.9V
Notes:
15. These STATUS pin voltages apply for an input voltage,V
IN
, of 7.5V < V
IN
< 60V. Below 7.5V the STATUS pin voltage levels reduce and therefore
may not report the correct status. For 5.4V < V
IN
< 7.5V the flag pin still reports an error by going low. At low V
IN
in Boost and Buck-boost modes
an over-current status may be indicated when operating at high boost ratios -– this due to the feedback loop increasing the sense voltage.
16. Severity 1 denotes lowest severity.
17. 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.
18. 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