TLE7233G Datasheet, PDF (15/32 Pages) Infineon Technologies AG – SPI Driver for Enhanced Relay Control

V_bat
V_DS(CL)
SPI Driver for Enhanced Relay Control
SPIDER - TLE7233G
Power Stages
OUT
L,
I_D
R_L
V_DS
GND
Figure 6 Output Clamp Implementation
OutputClamp .emf
Maximum Load Inductance
During demagnetization of inductive loads, energy has to be dissipated in the TLE7233G.
This energy can be calculated with following equation:
E = V_DS(CL) ⋅
V_{-----b--a---t---}–_----V_{-----D---S---(--C---L--)}
⋅
ln

1
–
-----------^R----^L----^â‹---^I--^L-----------


R_L
 ^V_bat ^{– V}_DS(CL) 
+ I_L
⋅ --^L----
R_L
Following equation simplifies under the assumption of R_L = 0:
E
=
1_--
2
L
I_L2
⋅

1
–
-------------^V-----^b--^a---^t-------------


 ^V_bat ^{– V}_DS(CL) 
The maximum energy, which is converted into heat, is limited by the thermal design of the component.
6.3
Timing Diagrams
The power transistors are switched on and off with a dedicated slope via the IN bits of the serial peripheral
interface SPI. The switching times t_ON and t_OFF are designed equally.
CS
V_DS
80%
SPI: ON
t_ON
SPI: OFF
t_OFF
t
20%
Figure 7 Switching a Resistive Load
t
SwitchOn.emf
In input mode, a high signal at the input pin is equivalent to a SPI ON command and a low signal to SPI OFF
command respectively. Please refer to Section 9.3 for details on operation modes.
The listed switching times are not valid, when switching to or from stand-by mode.
Datasheet
15
Rev. 1.0, 2008-02-28