Data Sheet

19

Rev. 1.4, 2014-10-28

TLE8209-2

Protection and Monitoring

8

Protection and Monitoring

Both output stages of the TLE8209-2 are equipped with fault diagnostic functions:

•

Short to battery voltage (SCB). Can be detected when low side-switches are turned on

•

Short to ground (SCG). Can be detected when high side-switches are turned on

•

Open load (OL). Can be detected in inactive mode

•

Over-temperature (OT). Can be detected in active and inactive mode

•

VDD over- and under voltage (Chapter 5.2)

•

Battery under voltage detection. Can be detected in active and inactive mode

Individual detection for each output in single switch operation mode (SCB, SCG, OL) is possible. The

corresponding diagnostics bits for each failure will be set in the SPI according to Table 8 “Failure Encoding” on

Page 31.

8.1

Diagnosis in Status Flag Mode

Instead of using the SPI interface for control and diagnosis of the TLE8209-2, the device can also be set into status

flag mode by connecting pin VDDIO to GND as described in Chapter 5.3.

In status flag mode the pin SF will be pulled low in the following cases:

•

undervoltage at VS

•

bridge disabled by ABE or DIS

•

bridge disabled by VDD monitoring

•

bridge disabled by short circuit detection

•

overtemperature shut down

8.2

Current Limitation

To limit the output current at low power loss, a chopper current limitation is integrated. Current measurement for

current limitation is done in the high side path. This requires high side freewheeling in case of active current

limitation.

Figure 10

Chopper Current Limitation

Figure 10 shows the behavior of the current limitation for over current detection in HS1. It applies accordingly also

for HS2:

switched to high (e.g. LS2->OFF, HS2->ON), independent of the input signal at IN2. This leads to a slow-decay

time

LS2

HS2

HS1

LS1