TLE7250V_15 Datasheet, PDF (29/34 Pages) Infineon Technologies AG – High Speed CAN-Transceiver

TLE7250VLE
TLE7250VSJ
Application Information
8.3.1 Mode Change while the TxD Signal is “low”
The example in Figure 14 shows a mode change to normal-operating mode while the TxD input is logical “low”.
The HS CAN signal is “recessive”, assuming all other HS CAN bus subscribers are also sending a “recessive” bus
signal.
While the transceiver TLE7250V is in power-save mode, the transmitter and the normal-mode receiver are turned
off. The TLE7250V drives no signal to the HS CAN bus nor does it receive any signal from the HS CAN bus.
Changing the NEN to logical “low” turns the mode of operation to normal-operating mode, while the TxD input
signal remains logical “low”. The transmitter and the normal-mode receiver remain disabled until the mode
transition is completed. In normal-operating mode the transmitter and the normal-mode receiver are active. The
“low” signal on the TxD input drives a “dominant” signal to the HS CAN bus and the RxD output becomes logical
“low” following the “dominant” signal on the HS CAN bus.
Changing the NEN pin back to logical “high”, disables the transmitter and normal-mode receiver again. The RxD
output pin is blocked and set to logical “high” with the start of the mode transition. The TxD input and the transmitter
are blocked and the HS CAN bus becomes “recessive”.
Note: The signals on the HS CAN bus are “recessive”, the “dominant” signal is
generated by the TxD input signal
NEN
t = t_Mode
t = t_Mode
t
TxD
t
V_Diff
t
RxD
power-save transition
normal-operating
transition
t
power-save mode
normal-mode RxD output normal-mode receiver RxD output
receiver disabled blocked
active
blocked
normal-mode receiver
disabled
TxD input and transmitter
blocked
TxD input and transmitter
active
Figure 14 Example for a mode change while the TxD is “low”
TxD input and transmitter blocked
Data Sheet
29
Rev. 1.0, 2015-08-12