Clock gating

About: Clock gating is a research topic. Over the lifetime, 7838 publications have been published within this topic receiving 107903 citations.

Duty-cycle regulator

Abstract: A duty-cycle regulation method for deriving an output clock signal having a predetermined duty cycle from an input clock signal having an arbitrary duty cycle. Once the input clock signal is received, an output clock storage element is switched to a first state upon detecting a transition in the input clock signal for driving the output clock signal to a first signal level. The output clock storage element is then switched to a second state after a delay interval equal to a fraction of the period for driving the output clock signal to a second signal level. The fraction of the period can be programmed to a pre-selected value.

Variable chip-clocking mechanism

Abstract: The performance of some chips (e.g., VLSI processors) may be increased by running the internal circuits at higher clock rates, but use of a higher clock rate is limited by the heat-dissipation ability of the chip's package. Apparatus and a method is described for estimating the total heat accumulated for dissipation at any given time. For the periods that the chip is idle, the clock rate is decreased to reduce heat generation. The heat saved while the chip is idling is available for use later to increase the clock rate above normal, provided that the total heat generated does not exceed the heat-dissipation capacity of the package.

Circuit and method for translating signals between clock domains in a microprocessor

Abstract: A microprocessor (5) including a clock domain translation circuit (50a) for communicating a digital signal from a high speed clock domain to a low speed clock domain is disclosed. The disclosed microprocessor (5) includes clock generation circuitry (20) which generates internal and bus clocks at different multiples of a system clock signal. The clock generation circuitry (20) includes a counter (60) that indicates, for a given frequency ratio, signals (REGION) indicating the current phase region of the faster clock (PCLK) relative to the slower clock (BCLK). The clock domain translation circuit (50a) includes a series of input registers (82, 84) in sequence, with the output of each as well as the input signal line (IN PCLK) coupled to inputs of a multiplexer (80). The multiplexer (80) selects either the input signal directly or the output of one of the registers for application to an output register (90), clocked by the slower clock signal (BCLK), depending upon the phase region of the faster clock (PCLK) relative to the slower clock (BCLK) for communication of that signal. As a result, the input digital signal is held for enough time to be properly clocked in, depending upon the phase region, thus enabling frequency ratios of non-integer values to be utilized in system operation.

Hierarchical Power Distribution with 20 Power Domains in 90-nm Low-Power Multi-CPU Processor

Abstract: Hierarchical power distribution using a power tree is developed. It supports fine-grained power gating with dozens of power domains like fine-grained clock gating and effectively reduces leakage currents for 1-million-gate power domains to 1/4000 in multi-CPU processors with minimal area overhead. This paper demonstrates the integration of 20 power domains in a 90nm single-chip 3G cellular phone processor

Clock recovery circuits with instantaneous locking

Abstract: Clock recovery circuits based on matched gated oscillators are proposed. Lock is acquired on the first data transition, even with non-return-to-zero line coding and with instantaneous and arbitrarily large phase shifts of the incoming signal. Simulated results of a fully integrated 650 Mbit/s clock recovery circuit designed in an existing 0.9 μm CMOS technology are also presented.