Adaptive skew control of data-strobe encoding for mobile display serial transceiver

This paper presents a new skew control technique for a high speed mobile display serial interface. Unstable frequency and distorted duty ratio of recovered clock from the skew of data and strobe can be adjusted simultaneously by the proposed adaptive strobe delay controller (ASDC). Clock regulation is important because a raster image is re-constructed by using pixel clock from serialized host sending image data. By converting detected skews to voltage level and using a voltage controlled delay line (VCDL), the proposed adaptive skew control technique solves the problems of image distortion which are caused by several mismatched skew elements between data and exclusive OR (XOR) encoded strobe signal. The proposed skew controller and its related transceiver were implemented and also verified using a mega-pixel mobile image sensor. This technique has an output duty error of less than 3% under the instantaneous duty error of 20% and the implemented systems shows a good image quality from 500 MHz to 1 GHz normal operation with 3.5 mW power dissipation.