TLE7251V_15 Datasheet, PDF (14/36 Pages) Infineon Technologies AG – High Speed CAN-Transceiver with Bus Wake-up

TLE7251VLE
TLE7251VSJ
Functional Description
4.3.5
Undervoltage on the Transmitter Supply V_CC
In case the transmitter supply V_CC falls below the threshold V_CC < V_CC(UV,F), the transceiver TLE7251V changes
the mode of operation to forced stand-by mode. The transmitter and also the normal-mode receiver of the
TLE7251V are powered by the V_CC supply. In case of an insufficient V_CC supply, the TLE7251V can neither
transmit the CANH and CANL signals correctly to the bus, nor can it receive them properly. Therefore the
TLE7251V blocks the transmitter and the receiver in forced stand-by mode. The low-power receiver is active in
forced stand-by mode (see Figure 7).
The undervoltage detection on the transmitter supply V_CC is only active in normal-operating mode (see Figure 5).
digital supply voltage VIO = “on”
VCC
VCC undervoltage monitor
VCC(UV,F)
hysteresis
VCC(UV,H)
VCC undervoltage monitor
VCC(UV,R)
tDelay(UV) delay time undervoltage
normal-operating mode
STB
forced stand-by mode
t
normal-operating mode
Assuming the STB remains “low”. The “low” signal is driven by the external microcontroller
t
Figure 7 Undervoltage on the transmitter supply V_CC
4.3.6 Voltage Adaption to the Microcontroller Supply
The HS CAN transceiver TLE7251V has two different power supplies, V_CC and V_IO. The power supply V_CC supplies
the transmitter and the normal-mode receiver. The power supply V_IO supplies the digital input and output buffers,
the low-power receiver, the wake-up logic and it is also the main power domain for the internal logic.
To adjust the digital input and output levels of the TLE7251V to the I/O levels of the external microcontroller,
connect the power supply V_IO to the microcontroller I/O supply voltage (see Figure 14).
Note: In case the digital supply voltage V_IO is not required in the application, connect the digital supply voltage V_IO
to the transmitter supply V_CC.
Data Sheet
14
Rev. 1.0, 2015-09-10