A6250X16W EMMICRO [EM Microelectronic - MARIN SA], A6250X16W Datasheet - Page 7

• Manufacturer Part Number: A6250X16W
• Description: High Efficiency Linear Power Supply with Accurate Power Surveillance and Software Monitoring
• Manufacturer: EMMICRO [EM Microelectronic - MARIN SA]

Watchdog Timeout Period Description
The watch dog time out pe riod is di vided into two parts, a
“closed" win dow and an “open" win dow (see Fig. 3) and is
de fined by two pa ram e ters, T
Per cent age (OWP).The closed win dow starts just af ter the
watch dog timer re sets and is de fined by T
OWP(T
win dow fin ishes and lasts till T
win dow time is de fined by T
For ex am ple if T
20% this means the closed win dow lasts dur ing first the
80 ms (T
open win dow the next 40 ms (T
ms). The watch dog can be ser viced be tween 80 ms and
T
WD
versus V
WD
CW
).The open win dow starts af ter the closed time
= 80 ms = 100 ms - 0.2 (100 ms)) and the
OUTPUT
WD
= 100 ms (ac tual value) and OWP = ±
at T
J
= +25 °C
OW
WD
WD
= 2 x OWP(T
OW
+ OWP(T
= 2 x 0.2 (100 ms) = 40
and the Open Win dow
WD
WD
). The open
CW
).
= T
Fig. 8
WD
-
T
120 ms af ter the timer re set. How ever as the time base is
±10% ac cu rate, soft ware must use the fol low ing cal cu la -
tion for ser vic ing sig nal TCL dur ing the open win dow:
Re lated to curves (Fig. 10 to Fig. 20), es pe cially Fig. 19
and Fig. 20, the re la tion be tween T
be de fined. Let us take an ex am ple de scrib ing the vari a -
tions due to pro duc tion and tem per a ture:
1. Choice, T
2. Re lated to Fig. 20, the co ef fi cient (T
3. R
4. The ra tio be tween T
5. If you fixed a TCL pe riod = 26 ms
WD
where R
= 25.4 ms is 0.975. Then the re la tion over the
Pro duc tion and the full tem per a ture range is,
TCL pe riod = 0.975 x T
TCL pe riod =
a) ±10 % while PRODUCTION value unknown for the
b) ±5 % while op er at ing TEMPERATURE range
If dur ing your pro duc tion the T
at T
then the TCL pe riod range will be much larger for the
full op er at ing tem per a ture.
EXT
versus R at T
cus tomer when R
-40°C
R
J
(typ.) = 26 x 1.155 = 30.0 k .
EXT
= +25°C and the µC can ad just the TCL pe riod,
EXT
WD
26 x 1.155
T
is in k and T
= 26 ms.
J
0.975
0.975 x R
+125°C.
J
= +25 °C
1.155
WD
EXT
= 30.8 k
= 26 ms and the (TCL pe riod)
WD
EXT
WD
123 k .
0.975 x R
in ms.
, as typ i cal value.
WD
WD
time can be mea sured
and R
WD
EXT
A6250
to R
or
EXT
EXT
could eas ily
) is 1.125
Fig. 9
7