Design Of A Spread‐Spectrum Clock Generator For DisplayPort Standard

DisplayPort Standard is a new digital display interface designed by Video Electronic Standard Association, which defines the digital video /audio inter‐contact between the computer and monitor or the computer and family cinema. As the successor of DVI, DisplayPort standard support the high definition audio signal transmission, higher resolution and while transmit video signal. DisplayPort standard may substitute High Definition Media Interface (HDMI) by the advantage of total bandwidth and tax. Now DisplayPort has got the support from industrial giant like AMD, Intel, NVIDIA, Dell, HP, Lenovo, Philips, Samsung.This issue intends to design a spread‐spectrum clock for DisplayPort. We set the system parameter and the performance requirements of the blocks on the basis of comprehensive consideration on power, area and performance. We use TSPC D flip‐flop for divider, none‐dead‐zone structure for phase‐frequency‐detector, current‐steering structure for charge pump and two‐stage ring oscillator for VCO. In addition, we design the bandgap and LDO to make the current of charge pump and voltage of VCO more stable. For reducing electromagnetic interference, we use the triangular waveform modulation on the control voltage.This design is implemented with tsmc0.18μm process, 3.3V power supply. Simulation on the behavior‐level and transistor‐level testify that this design satisfy the requirement of DisplayPort.