Application Notes

Measurement Characteristics of an Automotive LED Driver Based on a Hybrid Controller

This application note describes different measurement techniques and methods for an automotive lighting module based on a hybrid controller design. Of course, a lighting module in such an environment has to fulfil requirements according to the automotive standard, which is typically a relatively high-level standard compare to the industry standard. The oscilloscope is a perfect tool for this application to verify the set of requirements because time domain signals (analog and digital) are present in the whole design. Furthermore, measurements in the frequency domain have to be performed, which a modern oscilloscope can fulfil. In addition to the oscilloscope, a programmable power supply supports the measurement in several measurements. The set of requirements are the main reason why a hybrid controller from Microchip is a great choice for this design because it provides tremendous analogue and digital capabilities. The hybrid controller provides beside the analogue functions like an operational amplifier digital functions like analog-to-digital converter and interface functions like UART, CAN or LIN to interact with other systems. The programmable software part is hosted in the digital part. The digital part of the controller implements the communication interface and provides status information to the outer system controller. The light source itself has to avoid any flicker and shall be capable to dim to different lighting levels. Wide input voltage variations and efficiency have to be taken into account during the design of a converter dedicated for automotive applications. Nevertheless, the measurement considerations presented with the design are valid and applicable in other professional lighting industries as well.

Thanks to Mr. Andreas Reiter and Mr. Milan Marjanovic from Microchip who provided us with hardware and software and their great expertise to create this application note.

Measurement Characteristics of an Automotive LED Driver Based on a Hybrid Controller | GFM339