TLE7209-3R Datasheet, PDF (6/32 Pages) Infineon Technologies AG – Short circuit protection

TLE 7209-3R
Circuit Description
2.2
Power Stages
Four n-channel power-DMOS transistors build up the output H-bridge. Integrated circuits
protect the outputs against over current and over-temperature if there is a short-circuit to
ground, to the supply voltage or across the load. Positive and negative voltage spikes,
which occur when switching inductive loads, are limited by integrated freewheeling
diodes. To drive the gates of the high-side DMOS, an internal charge pump is integrated
to generate a voltage higher than the supply voltage.
2.2.1 Chopper Current Limitation
To limit the output current at low power loss, a chopper current limitation is integrated as
shown in Figure 3. The current is measured by sense cells integrated in the low-side
switches. When the current limit I_L has been exceeded for a time t_b, all output stages are
switched off for a fixed time t_a.
Blanking time t_b
Current limit I_L
Switch-off time t_a
Figure 3 Chopper current limitation
time
Data Sheet
6
Rev. 1.0, 2014-02-03