TLE8262-2E Datasheet, PDF (24/94 Pages) Infineon Technologies AG – Universal System Basis Chip

TLE8262-2E
External Voltage Regulator
7
External Voltage Regulator
7.1
Block Description
V_cc3 is activated via SPI. The external voltage regulator circuitry is designed to drive an external PNP transistor to
increase output current flexibility. Four pins are used: V_S, V_cc3base, V_cc3shunt and V_cc3ref. One transistor is tested
during production. An input voltage up to V_SMAX is regulated to V_Q,nom = 5.0 V with a precision of ±4%. The output
current of the transistor is monitored via an external shunt resistor. The state of V_cc3 is reported in the diagnostic
SPI register. When battery voltage is below the minimum operating battery voltage V_s < V_VextUV, the external
voltage regulator switches off. Figure 7 shows the behavior during this phase. The shunt is used for overcurrent
limitation. If this feature is not needed, connect pins V_cc3shunt and V_s together.
Since the junction temperature of the external PNP transistor cannot be read, it cannot be protected against over
temperature by the SBC, and so the thermal behavior has to be checked by the application.
VS
Vcc3 shunt
Vcc 3base
Vcc 3ref
V S-VCC3shunt>
Vs hunt_thr es hold
RBE
IC C 3ba s e
+
State machine
-
VR EF
Figure 6 Functional Block Diagram
External voltage diagram .vsd
7.2
External Voltage Regulator Mode
It is possible to turn the V_cc3 ON or OFF via SPI command, depending on the SBC modes. Table 4 identifies the
possible states, based on the different SBC modes.
7.3
External Voltage Regulator State by SBC Mode
Table 4 shows the possible states of the V_cc3 external voltage regulator as a function of the SBC mode.
Table 4 External Voltage Regulator State by SBC Mode
SBC Mode
V_cc3
INIT Mode
OFF
Normal Mode
ON
Sleep Mode
OFF
Restart Mode
Unchanged
SW Flash Mode
ON
Stop Mode
ON
Fail-Safe Mode
OFF
OFF
OFF
OFF
Data Sheet
24
Rev. 1.0, 2009-05-26