An app note(PDF) from Freescale Semiconductor
This document describes the current sense performance of eXtreme switches, and describes the enhanced current sense mode dedicated for low current loads, such as light emitting diodes (LED). This application note also presents the accuracy for 7.0 mOhm and 17 mOhm channels, and the practical implementation of a calibration procedure to get optimized results.
The eXtreme switch is the latest achievement in automotive lighting drivers. It consists of a scalable family of devices compatible in software, MCU interface, and footprint. This product family is designed for low-voltage automotive and industrial lighting applications. This high-side power switch family includes the MC07XS6517, which is designed to drive a wide range of light sources, including HID ballasts, incandescent bulbs, or LEDs.
Programming, control, and diagnostics are accomplished using a 16-bit SPI interface, which provides a large panel of configuration, analog, and digital information related to the device in its application, and a full set of protection features to ensure its safety. All information provided by the SMARTMOS through the SPI gives the MCU all the key information to reflect device and output status. This device also provides a wide flexibility of configurations in addition to highly sophisticated fault and failure mode handling.As an example, it integrates an enhanced PWM module with 8-bit duty cycle capability. Each output has an independent prescaler to control PWM frequency, phasing, and outputedge shaping, to improve electromagnetic compatibility.