BTS5682E Datasheet, PDF (32/46 Pages) Infineon Technologies AG – SPI Power Controller

SPOC - BTS5682E
Diagnosis
In case of over current as well as over temperature, the current sense signal of the affected channel is switched
off. To distinguish between over temperature and over load, the SPI diagnosis word can be used. Whereas the
over load flag is cleared every time the diagnosis is transmitted, the over temperature flag is cleared by a dedicated
SPI command (HWCR.CTL).
Details about timings between the current sense signal I_IS and the output voltage V_OUT and the load current I_L can
be found in Figure 17.
IN _OFF
V _OUT
ON
t_ON
I_L
OFF
t_OFF
t
t
t_{sIS (ON)}
t _{sIS (LC)}
t _{dIS (OFF)}
t
I_IS
Figure 17 Timing of Current Sense Signal
t
SenseTiming.emf
Current Sense Multiplexer
There is a current sense multiplexer implemented in the SPOC - BTS5682E that routes the sense current of the
selected channel to the diagnosis pin IS. The channel is selected via SPI register DCR.MUX. The sense current
also can be disabled by SPI register DCR.MUX. For details on timing of the current sense multiplexer, please refer
to Figure 18.
CS
DCR.MUX 110 000
001
110
I_IS
t_{sIS (E N)}
t_{sIS (MUX )}
t _{dIS (MUX )}
t
Figure 18 Timing of Current Sense Multiplexer
t
MuxTiming.emf
8.3
Switch Bypass Diagnosis
To detect short circuit to V_BB, there is a switch bypass monitor implemented. In case of short circuit between the
output pin OUT and V_BB in ON-state, the current will flow through the power transistor as well as through the short
circuit (bypass) with undefined ratio. As a result, the current sense signal will show lower values than expected by
the load current. In OFF-state, the output voltage will stay close to V_BB potential which means a small V_DS.
The switch bypass monitor compares the voltage V_DS across the power transistor of that channel which is selected
by the current sense multiplexer (DCR.MUX) with threshold V_DS(SB). The result of comparison can be read in SPI
register DCR.SBM.
Data Sheet
32
Rev. 1.0, 2008-01-22