TLE4678_15 Datasheet, PDF (25/37 Pages) Infineon Technologies AG – Low Drop Out Linear Voltage Regulator

TLE4678
Watchdog Function
Supply
I
RWADJ ,ext
(optional)
WADJ
Control
I_WADJ
RWADJ ,int
VWADJ,th
Int.
Supply
WI Edge
Detect
OR
S1
R
V_DW,hi
I_D,ch
IDW ,dsch
GND
Figure 9 Block Diagram Watchdog Circuit
Q
RWO
I_Q
VDD
CQ
Micro-
Controller
WO
IWO
V_DW
&
Reset
WI
I/O
D
CD
BlockDiagram _WatchdogAdjust .vsd
GND
Figure 10 Watchdog Output “WO”
The watchdog output “WO” is an open collector output with an integrated pull-up resistor. In case a lower-
ohmic “WO” signal is desired, an external pull-up resistor to the output “Q” can be connected. Since the
maximum “WO” sink current is limited, the optional external resistor R_WO,ext needs to be sized to comply with
the watchdog output sink current (see Item 8.2.15 and Item 8.2.16).
Watchdog Input “WI”
The watchdog is triggered by a positive edge at the watchdog input “WI”. The signal is filtered by a band-pass
filter and therefore its amplitude and slope have to comply with the specification Item 8.2.10 to Item 8.2.14.
For details on the test pulse applied, see Figure 11.
V_WI
VWI,hi
tWI,p
VWI,lo
d VWI / d t
t
Figure 11 Test Pulses Watchdog Input WI
Datasheet
25
V_WI
VWI,hi
VWI,lo
1 / fWI
t
Rev. 1.2, 2014-10-17