TLE8209-2SA Datasheet, PDF (18/38 Pages) Infineon Technologies AG – SPI Programmable H-Bridge

TLE8209-2SA
Protection and Monitoring
8
Protection and Monitoring
Both output stages of the TLE8209-2SA 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 29.
8.1
Diagnosis in Status Flag Mode
Instead of using the SPI interface for control and diagnosis of the TLE8209-2SA, 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
SF will not be pulled low if V_DD is below the power on reset threshold (VDD_POR).
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.
t_b
I_L
I_hys
t_trans
HS1
HS2
LS1
LS2
time
Figure 9 Chopper Current Limitation
Figure 9 shows the behavior of the current limitation for over current detection in HS1. It applies accordingly also
for HS2:
When the current in high-side switch of OUT1 (HS1) exceeds the limit I_L longer than the blanking time t_b, OUT2 is
switched to high (e.g. LS2->OFF, HS2->ON), independent of the input signal at IN2. This leads to a slow-decay
current decrease in the load and in HS1. As soon as the current falls below I_L-I_hys, OUT2 is switched back to normal
Data Sheet
18
Rev. 1.0, 2010-02-16