A 4-Channel High-Precision Constant Current Control ASIC for Automotive Transmission Applications

An ASIC (application specific integrated circuit) implementation of a 4-channel high precision, switched mode, constant current controller is presented. The device is reliable and maintains an output current accuracy of 1.5% in the automotive environment. A brief system overview is presented with focus on the ASIC itself. The most important requirements such as temperature range, common mode rejection, accuracy and repeatability are discussed. The core circuits, such as bandgap reference and input amplifier are shown in detail. An overview on the digital implementation is presented and selected measurement results prove outstanding accuracy performance under automotive conditions