Clock distribution using cooperative ring oscillators

Analysis and verification of interconnected rings as clock distribution networks

“…There was shown that local nets have linear metal-cost and global nets have exponential metal-cost per stage, this is a very important observation because the current trend is to increase the number of stages on the nets and the complexity of global nets also increase. By repeating the basic ring, the array will keep the basic cell properties satisfactorily, and the power consumption is proportional to the number of rings [8]- [12].…”

“…To obtain further information about the analytical model go to [8]. These works deal with CDNs that we denominate "locals" (from GALS).…”

“…Nevertheless, the systems are becoming larger (MCM and SoC) and frequencies faster, then the problem of TOF is worst and nets that optimally distribute the clock signal are required [1]. New techniques have been proposed to solve this problem in clock distribution networks (CDNs); some techniques offer solutions at the process or fabrication levels such as the flipchip package [1]; or at the architecture level as asynchronous communication between blocks [7]; or the use of interconnected rings or oscillators as the (local net) CDNs [8]- [12]. The interconnected rings technique has proved to generate, lock and feed a clock signal to more than one chip in a reliable way [9] and has been used for quadrature generators and with a sleep mode [10].…”

A Performance Comparison of CMOS Voltage-Controlled Ring Oscillators for its Application to Generation and Distribution Clock Networks

“…Today, in order to solve some problems associated with the GCN, some of the design philosophies that are under study are networks using distributed oscillators [4][5][6][7][8][9][10][11], and cooperative or connected ring oscillators [12][13][14][15][16][17][18]. In this work, we make use of the last philosophy and the networks are named Local Clock Generation and Distribution Networks (LCGDN) [4,6].…”

A multi-level transmission line network approach for multi-giga hertz clock distribution

“…Galton et al [7] showed that when the wire length is shorter than one quarter wavelength, the transmission line can synchronize oscillators both in phase and magnitude. Several other researches utilized the synchronization capability of the transmission line in clock distribution by connecting the distributed PLLs together with transmission lines [8,9,20]. In order to compensate the lossy nature of the on-chip transmission lines, O'Mahony et al [14] use distributed transconductors along the transmission line to generate the standing wave.…”