th3122 Melexis Company, th3122 Datasheet - Page 5

• Manufacturer Part Number: th3122
• Description: K-bus Transceiver With Integrated Voltage Regulator
• Manufacturer: Melexis Company

Figure 7 - Initialization
The input EN has an internal pull down resistor. If
EN=high, the internal pull down current is switched off to
minimize the quiescent current.
RESET Output
The RESET output is switched from low to high if V
switched on and V
If the voltage V
output is switched from high to low after the time t
reached.
The voltage level for V
corresponding times t
analogue input VTR.
Wake up with BUS traffic
If the regulator is put in standby mode it can be woken
up with the BUS interface. Every pulse on the BUS (high
pulse or low pulse) with a pulse width of min. 45
switch on the regulator.
After the BUS has woken up the regulator, it can only be
switched off with a high level followed by a low level on
the EN pin.
Reset Programming on VTR
With the VTR pin the reset switches off levels and delay
time can be programmed.
The voltage on VCC influences the reset function.
3901003122
Rev 004
RESET
VCC
VS
CC
V
drops below V
RESEIN
CC
>V
RES
RESEIN
t
Res
can be programmed via the
RES1
after the time t
RES1
or V
K-Bus Transceiver with integrated Voltage Regulator
and V
RES2
then the RESET
RES2
RES
.
rr
and the
has been
t
V
rr
s will
RES1/2
S
is
Page 5
VTR-Programming
The voltage on VTR input is read out if the voltage at this
pin is higher than V
switch off voltage V
switches on the pull up current source if VTR=low or the
pull down current source if VTR=high. The sources are
active for one oscillator cycle. The level changes during
this procedure on VTR, which depends on the external
pull up or pull down resistors control the reset time t
Temperature Limitation
If the junction temperature 150ºC < T
temperature recognition will be active and the regulator
voltage and the BUS driver will be switched off. After T
falls below 140ºC the TH3122 will be initialized,
independently of the voltage levels on EN and BUS.
The function of the TH3122 is possible between T
and the switch off temperature, but small parameter
differences can appear.
Low Voltage Detection V
Low voltage on V
If V
output
operating range is V
generates a high level.
Universal Comparator
The TH3122 consist of a universal comparator for
general use. The positive input of this comparator is
connected to the pin SI. The input voltage range of SI is
0V...V
reference voltage at high or low level and the comparator
output SO drives a 5V digital signal.
VTR = GND
VTR = VCC
VTR with R
VTR with R
S
has reached the level of V
S.
VTR-Mode
The input voltage is compared with a fixed
generates
50k
50k
S
to GND
to VCC
is monitored on SENSE output.
RESEIN
RES
S
. With the next oscillator cycle it
> 7.8V and the SENSE output
low
. This value defines the reset
V
V
V
V
S
RES
RES
RES
RES
S
level.
= V
= V
= V
= V
=6.8V then the SENSE
V
RES1
RES2
RES1
RES2
RES
j
TH3122
< 170ºC the over
= 3.15V
= 4.65V
= 3.15V
= 4.65V
The
normal
Dec/04
100ms
100ms
15ms
15ms
Res
t
Res
Amax
j