TLE4678-2_15 Datasheet, PDF (23/33 Pages) Infineon Technologies AG – Low Drop Out Linear Voltage Regulator

TLE4678-2
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
Q
RWO
I_Q
VDD
CQ
Micro-
Controller
WO
IWO
V_DW
&
Reset
WI
I/O
D
CD
BlockDiagram _WatchdogAdjust .vsd
GND
Figure 8 Block Diagram Watchdog Circuit
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 Table “Watchdog Output Low Voltage” on Page 25 and Table “Watchdog Output
Maximum Sink Current” on Page 25).
Watchdog Input “WI”
The watchdog is triggered by an positive edge at the watchdog input “WI”. The signal is filtered by a bandpass
filter and therefore its amplitude and slope has to comply with the specification Table “Watchdog Input” on
Page 25 to Table “Watchdog Input Signal Slew Rate” on Page 25. For details on the test pulse applied, see
Figure 9.
Data Sheet
23
Rev. 1.0, 2014-03-03