TLE7250_15 Datasheet, PDF (28/34 Pages) Infineon Technologies AG – High Speed CAN-Transceiver

TLE7250LE
TLE7250SJ
Application Information
8.3.1 Mode Change while the TxD Signal is “low”
The example in Figure 13 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 TLE7250 is in power-save mode, the transmitter and the normal-mode receiver are turned
off. The TLE7250 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 transceiver 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 pin becomes
logical “low”, following the “dominant” signal on the HS CAN bus.
Changing the mode of operation from normal-operating mode to receive-only mode by setting the NRM input pin
to “low”, disables the transmitter and the TxD input, but the normal-mode receiver and the RxD output remain
active. The HS CAN bus becomes “recessive” since the transmitter is disabled. The RxD input indicates the
“recessive” HS CAN bus signal by a logical “high” output signal (see also the example in Figure 13).
Mode changes between the power-save mode on the one side and the normal-operating mode or the receive-only
mode on the other side, disable the transmitter and the normal-mode receiver. No signal can be driven to the
HS CAN bus nor can it be received from the HS CAN bus. Mode changes between the normal-operating mode
and the receive-only mode disable the transmitter and the normal mode receiver remains active. The HS CAN
transceiver TLE7250 monitors the HS CAN bus also during the mode transition from normal-operating mode to
receive-only mode and vice versa.
8.3.2 Mode Change while the Bus Signal is “dominant”
The example in Figure 14 shows a mode change while the bus is “dominant” and the TxD input signal is set to
logical “high”.
While the transceiver TLE7250 is in power-save mode, the transmitter and the normal-mode receiver are turned
off. The TLE7250 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 “high”. The transmitter and the normal-mode receiver remain disabled until the mode
transition is completed. In normal-operating mode the transceiver and the receiver are active and therefor the RxD
output changes to logical “low” indicating the “dominant” signal on the HS CAN bus.
Changing the mode of operation from normal-operating mode to receive-only mode by setting the NRM input pin
to “low”, disables the transmitter and the TxD input, but the normal-mode receiver and the RxD output remain
active. Since the “dominant” signal on the HS CAN bus is driven by another HS CAN bus subscriber, the bus
remains “dominant” and the RxD input indicates the “dominant” HS CAN bus signal by a logical “low” output signal
(see also the example in Figure 14).
Data Sheet
28
Rev. 1.0, 2015-08-12