TLE75008-EMD_15 Datasheet, PDF (37/64 Pages) Infineon Technologies AG – SPI Driver for Enhanced Relay Control

TLE75008-EMD
Power Stages
V_S
Low -side
Channel
L,
I_L
R_L
OUT ^{I L_D}
V_DS
V _DS(CL)
GND
Figure 16 Output Clamp concept
PowerStage_LS.emf
7.1.3 Maximum Load Inductance
During demagnetization of inductive loads, energy has to be dissipated in the TLE75008-EMD. Equation (7.1)
shows how to calculate the energy for low-side switches:
E = V_DS(CL) ⋅
V-----_S----–_{-----V----D----S--(--C----L--)}
R_L
⋅
ln _⎝⎛1
–
-V----_S----R_–----^L-V----^â‹_D---I-_S-^L-₍--_C---_L---_{)⎠⎞}
+
I_L
⋅ --L----
R_L
(7.1)
The maximum energy, which is converted into heat, is limited by the thermal design of the component. The E_AR
value provided in Table 2 assumes that all channels can dissipate the same energy when the inductances
connected to the outputs are demagnetized at the same time.
7.2
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.
Data Sheet
37
Rev. 1.1, 2015-09-25