TLE7257 Datasheet, PDF (15/31 Pages) Infineon Technologies AG – LIN Transceiver

4.8
Undervoltage Detection
TLE7257
Functional Description
Undervoltage
V_S
detection level V_S,UV,OFF
Undervoltage hysteresis V_S,UV,HYS
Supply voltage V_S
Undervoltage release level V_S,UV,ON
Power-on reset level V_S,UV,PON
Blanking time t_blank,UV
t
Normal Operation mode
Communication blocked
Normal Operation mode
Figure 11 Early undervoltage detection
TLE7257_UNDERVOLTAGE_EARLY
The TLE7257 has undervoltage detection on the V_S supply pin with two different thresholds:
• In Normal Operation mode the TLE7257 blocks the communication between the LIN bus and the
microcontroller when detecting undervoltage events. However, no mode change will occur. After V_S rises
above the undervoltage release level V_S,UV,REL, the bus communication interface will be released when the
signal on the TxD input goes “high”. See Figure 11.
• In case the V_S power supply drops down below the power-on reset level V_S,UV,PON the TLE7257 blocks the
communication between the LIN bus and the microcontroller, and also changes the operation mode to Sleep
mode after V_S supply recovery. The power-on reset level is active in all operation modes. See Figure 12.
Undervoltage
V_S
detection level V_S,UV,OFF
Undervoltage hysteresis V_S,UV,HYS
Normal Operation mode
Device unpowered
Communication blocked
Figure 12 Undervoltage detection and power-on reset
Supply voltage V_S
Undervoltage release level V_S,UV,ON
Power-on reset level V_S,UV,PON
Blanking time t_blank,UV
t
Sleep mode (EN = „low“)
Normal Operation mode (EN = “high“)
TLE7257_UNDERVOLTAGE_RESET
Data Sheet
15
Rev. 1.0, 2013-10-16