Application information, Zxld1374, A product line of diodes incorporated – Diodes ZXLD1374 User Manual
Page 26
ZXLD1374
Document number: DS35032 Rev. 3 - 2
26 of 39
September 2012
© Diodes Incorporated
ZXLD1374
A Product Line of
Diodes Incorporated
Application Information
(cont.)
VR EF
0V
0A
FLA
G
V
O
LTA
G
E
ST
A
T
U
S
V
O
L
TA
G
E
Normal
Operations
SEVERITY
4.5V
3.6V
2.7V
1.8V
0.9V
VAUX
UVLO
- VIN UVLO
- STALL
- OUT of REG
ZXLD1374
Switch OV
Over
Temperature
Over
Current
0
1
2
3
4
5
Figure 32 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
.
Diagnostic signals should be ignored
during the device start – up for 100μs.
The device start up sequence will be
initiated both during the first power on of
the device or after the PWM signal is kept
low for more than 15ms, initiating the
standby state of the device.
In particular, during the first 100μs the
diagnostic is signaling an over-current
then an out-of-regulation status. These
two events are due to the charging of the
inductor and are not true fault conditions.
Over-
current
Out of
regulation
ST
A
T
US
FL
AG
V
REF
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0
20
40
60
80
100
120
140
160
180
200
time (µs)
Co
il c
u
rre
nt
(
A
)
Over-
current
Out of
regulation
ST
A
T
US
FL
AG
V
REF
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0
20
40
60
80
100
120
140
160
180
200
time (µs)
Co
il c
u
rre
nt
(
A
)
Figure 33 Diagnostic During Start-Up