SPI Driver for Enhanced Relay Control

TLE7239SL

Overview

Data Sheet

5

Rev. 1.0, 2010-02-18

Detailed Description

The TLE7239SL is an eight channel high-side and low-side relay switch providing embedded protective functions.

The output stages incorporate two low-side switches (0.9

Ω per channel), four high-side switches (two channels

with 0.9

Ω and two channels with 1.6 Ω) and two auto-configuring high-side or low-side switches (0.9 Ω per

channel). The auto-configuring switches can be utilized in high-side or low-side configuration just by connecting

the load accordingly. They are also suitable to switch a 5 V supply line in high-side configuration. Protective and

diagnostic functions adjust automatically to the chosen configuration.

The 8 bit serial peripheral interface (SPI) is utilized for control and diagnosis of the device and the loads. The SPI

interface provides daisy chain capability in order to assemble multiple devices in one SPI chain by using the same

number of micro-controller pins.

The outstanding feature of this octal relay switch enables the output channels to keep their state at low battery

voltage. This is realized by an integrated power supply, especially designed to fulfill cranking mode requirements

supply is available.

Furthermore, the TLE7239SL is equipped with two input pins that can be individually routed to the output control

of each channel thus offering complete flexibility in design and PCB-layout. The input multiplexer is controlled via

SPI.

In limp home mode (fail-safe mode), the input pins are directly routed to the configurable output channels 4 and

5. The limp home mode operates independently of digital power supply and is activated via pin LHI.

The device provides full diagnosis of the load via open load, over load and short circuit detection. SPI diagnosis

flags indicate latched fault conditions that may have occurred.

Each output stage is protected against short circuit. In case of over load, the affected channel switches off. There

are temperature sensors available for each channel to protect the device against over temperature.

The device protects itself with a built in reverse polarity protection which prohibits intrinsic current flow through the

logic during reverse polarity. However the output stages still incorporate a reverse diode where current can flow

through during reverse polarity.

The power transistors are built by N-channel power MOSFETs. The inputs are ground referenced CMOS

compatible. The device is monolithically integrated in Smart Power Technology.