Data Sheet

13

Rev. 1.0, 2008-10-30

TLE7238GS

Power Supply

5

Power Supply

The TLE7238GS is supplied by two supply voltages

V

feed and used by the power switches and by an integrated power supply for the register banks. There is an under

voltage reset function implemented for the

V

are reset to their default values and the device is in sleep mode (standby). The SPI command CMD.WAKE = 1 is

switching the device to operation mode (ON), while a command CMD.STB = 1 send the device to sleep mode

(standby) again.

The

V

daisy chain function is available as soon as

V

between pins

V

5.1

Operation Modes

There is a limp home functionality implemented in the TLE7238GS, which is activated via pin LHI. Please refer to

Section 5.2 for details.

The device provides a sleep mode (stand by) to minimize current consumption, which also resets the register

banks. It is entered and left by dedicated SPI commands .The sleep mode current is minimized only when limp

home is inactive. After limp home, the device enters sleep mode automatically.

The following table shows the operation modes depending on

V

5.2

Limp Home Mode

The TLE7238GS offers the capability of driving dedicated channels during fail-safe operation of the system. This

limp home mode is activated by a high signal at pin LHI. In limp home mode, the SPI registers are reset and the

input pins are directly routed to the auto configuring channels (channel 4 and 5). As a result, the limp home

operation can be chosen for high-side and low-side driven loads.

Due to the integrated power supply, limp home operation is independent of digital power supply

V

stand-by, a high signal at pin LHI will wake up the device. After limp home operation, the device enters sleep mode

in any case.

5.3

Reset

There are several reset trigger implemented in the device. A reset switches off all channels and sets the registers

to default values. After any kind of reset, the transmission error flag (TER) is set.

Under Voltage Reset:

During this device condition a read on SPI always delivers the Standard Diagnostic Frame with a TER flag.

This under voltage reset is released when all the supply voltages levels are above under voltage threshold.

Operation Modes

VBB

0V

0V

0V

12 V

12V

12 V

12V

VDD

0 V5 V

5 V0 V0 V

5 V5 V

LHI

X

0V

5V

0V

5V

0V

5V

Switches operating

-

-

-

✓✓

✓✓

Limp Home

-

-

-

-

✓

-

✓

SPI & daisy-chain

-

✓

✓

--

✓

✓

Register Banks

reset

reset

reset

✓

reset

✓

reset

Diagnostic functions

-

-

-

✓

-

✓

-