TLE9221SX Datasheet, PDF (37/91 Pages) Infineon Technologies AG – FlexRay Transceiver

TLE9221SX
Power Supply Interface
ERRN
dReactionTime_ERRN
t
uV_CC
set uV_CC undervoltage bit
set error bit
dBDUVV_{CC_BLK}
uBDUVV_CC (Threshold)
uBDUVV_{CC_Hys}
t < dBDUVV_{CC_BLK}
dBDUVV_CC
set uV_CC undervoltage flag,
block host commands
non-low power mode
t
dBDRV_CC
clear uV_CC undervoltage flag,
release host commands
(return to the mode of operation
selected by the host command)
BD_Standby
Figure 27 Undervoltage event at uV_CC in non-low power mode
8.3.4
Undervoltage Event at uV_IO
The Central State Machine of the TLE9221SX handles an undervoltage event at the reference supply uV_IO in a
manner identical to an undervoltage event on the power supply uV_BAT.
The supply on the level shift input V_IO is the main reference for all digital inputs and outputs of the TLE9221SX. It
is also connected to the pad supply of the external microcontroller (see Figure 50). An undervoltage event on the
level shift input V_IO could lead to a misinterpretation of the digital input levels and could generate a false signal at
the digital outputs.
For fail-safe reasons, the TLE9221SX blocks the Host Interface, the Communication Controller Interface and the
Bus Guardian Interface after a small processing time (dReactionTime_ERRN) when an undervoltage event has been
detected on the reference supply uV_IO (see Figure 28). According to Table 2, all digital inputs are set to their
default level. All digital outputs are set to logical “low”.
The transceiver TLE9221SX detects an undervoltage event, if the supply at the pin V_IO drops for the time period
t > dBDUVV_{IO_BLK} below the undervoltage detection threshold uUV_IO (see Figure 28). Voltage fluctuations on uV_IO
shorter than dBDUV_{CC_BLK} are ignored and not recognized by the Power Supply Interface.
Although the Host Interface is blocked and the SIR is not accessible while the reference supply uV_IO is in
undervoltage condition, the transceiver sets the uV_IO undervoltage bit (bit 10) and the error bit (bit 11) (see
Figure 28). After the uV_IO undervoltage detection timer dBDUVV_IO expires, the uV_IO undervoltage flag is set and
the mode of operation changes to BD_Sleep mode (compare also to Chapter 9.3 and Table 14).
Data Sheet
37
Rev. 1.10, 2013-07-15