TLE75080-EMH Datasheet, PDF (41/80 Pages) Infineon Technologies AG – SPI Driver for Enhanced Relay Control

TLE75080-EMH
Power Stages
7.3
Switching Channels in parallel
In case of appearance of a short circuit with channels in parallel, it may happen that the two channels switch OFF
asynchronously, therefore bringing an additional thermal stress to the channel that switches OFF last. In order to
avoid this condition, it is possible to parametrize in the SPI registers the parallel operation of two neighbour
channels (bits HWCR.PAR). When operating in this mode, the fastest channel to react to an Over Load or Over
Temperature condition will deactivate also the other. The inductive energy that two channels can handle once set
in parallel is lower than twice the single channel energy (see P_7.6.11). It is possible to synchronize the following
couples of channels:
• channel 0 and channel 2 → HWCR.PAR (0) set to “1”
• channel 1 and channel 3 → HWCR.PAR (1) set to “1”
• channel 4 and channel 6 → HWCR.PAR (2) set to “1”
• channel 5 and channel 7 → HWCR.PAR (3) set to “1”
The synchronization bits influence only how the channels react to Over Load or Over Temperature conditions.
Synchronized channels have to be switched ON and OFF individually by the micro-controller.
7.4
“Bulb Inrush Mode” (BIM)
Although TLE75080-EMH is optimized for relays and LED, it may be necessary to use one or more of the outputs
to drive small lamps (typically 2 W) or electronic loads with a big input capacitor. In such operative conditions, at
the switch ON an inrush current may appear, reaching the overload current threshold which latches the channel
OFF (see Chapter 8.1 for further details). In normal operation the device waits until the microcontroller sends an
SPI command to clear the latches (register HWCR_OCL) allowing the channel to turn ON again. Usually this delay
is too long to transfer enough energy to the load.
If the corresponding bit BIM.OUTn is set to “1”, in case the channel reaches the overload current threshold or the
overtemperature threshold and latches OFF, it restarts automatically after a time t_INRUSH, allowing the load to go
out of the inrush phase. A time diagram is shown in Figure 17. As shown, the counter starts when the channel is
switched ON. Every channel switch OFF (independently from the entity controlling the channel - see Figure 18 for
further details) resets the bit BIM.OUTn to “0”.
While BIM.OUTn bits are set to “1”, ERRn bits may be also set to “1” but this doesn’t latch the channel OFF.
An internal timer set the bit BIM.OUTn back to “0” after 40 ms (parameter t_BIM) to prevent an excessive thermal
stress to the channel, especially in case of short circuit at the output.
TLE75080-EMH allows a per-channel selection of Bulb Inrush Mode (BIM) in order to be fully flexible without any
additional reliability risk.
Data Sheet
41
Rev. 1.0, 2016-06-22