STMicroelectronics AN2859 Application Note Multiplexed Diagnostics of AC Switches Using Two STCC08s

About this manual

The document presents a solution to reduce the number of microcontroller unit (MCU) input pins required to diagnose failures in multiple AC switches. It focuses on using two STMicroelectronics STCC08 devices with multiplexed diagnostics, providing technical recommendations for implementation.

The note details the principle of using an analog-to-digital converter (ADC) input on the MCU to read signals from the STCC08's AVF driver block. By configuring a divider bridge and analyzing voltage levels (Vstate), the system can distinguish between various states of two AC switches, including conducting, non-conducting, and specific failure modes such as diode mode or short circuit.

What's inside

• Multiplexed diagnostics principle
• Failure mode detection
• Vstate signal reading synchronization
• Gate level definition
• Resistance settings
• Detection windows digital value setting
• Application example

Frequently asked questions

What is the aim of this application note?

The aim is to present opportunities to reduce the number of input pins used on a microcontroller unit (MCU) to diagnose failures of several AC switches with the STCC08.

How many STCC08 devices are described in this document?

The document describes the multiplexed diagnostic of two STCC08 devices.

What type of MCU input should be used for the multiplexed diagnostic?

An analog/digital converter input (ADC) of the MCU should be used and must be configured with no pull-up resistor.