Diodes ZXLD1370 - Manual (Page 30)

ZXLD1370
Document number: DS32165 Rev. 5 - 2
30 of 39
www.diodes.com
September 2012
© Diodes Incorporated
ZXLD1370
A Product Line of
Diodes Incorporated
Application 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:
Table 2
Warning/Fault Condition
Severity
(Note 17)
Monitored
Parameters
FLAG Nominal STATUS Voltage
Normal operation H 4.5
Supply under-voltage
1 V
AUX
<5.6V L 4.5
2 V
IN
<5.6V L 3.6
Output current out of regulation
(Note 18)
2
V
SHP
outside normal voltage
range
L 3.6
Driver stalled with switch ‘on’, or ‘off’
(Note 19)
2 t
ON
, or t
OFF
>100µs L 3.6
Device temperature above maximum
recommended operating value
3 T
J
>+125°C L 1.8
Sense resistor current I
RS
above
specified maximum
4 V
SENSE
>0.32V 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
FLA
G VO
L
T
A
G
E
STA
T
U
S
VO
LTA
GE
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.
If V
ADJ
>1.7V, V
SENSE
may be greater than the excess coil current threshold in normal operation and an error will be reported. Hence, STATUS
and FLAG are only guaranteed for V
ADJ
<=V
REF
.