Clock State Machine for Low-Noise Frequency Ramping
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Solution Overview
Problem
Modern integrated circuits face noise issues due to high capacitance in clock trees, which interfere with component operation, especially during clock gating and reset sequencing, and existing noise management techniques are too slow for modern devices.
Innovation Solution
Implementing a mechanism to ramp clock signals gradually during state transitions, reducing the frequency change rate to minimize voltage noise, which can be achieved by forming control mechanisms within a microcircuit using methods like growth or deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If clock frequency is changed quickly from off state to multiple GHz frequencies, then clock control speed is improved, but voltage noise increases due to high dI/dT
Solution Approach 1:
The patent applies periodic action by using a state machine that transitions the clock through multiple intermediate frequency states rather than a single abrupt change. The clock frequency is ramped up or down through a sequence of discrete steps (e.g., from 0 to 1/4 frequency to 1/2 frequency to full frequency), creating a periodic progression that reduces the instantaneous rate of change of current (dI/dT) while still achieving fast overall clock control.
2Object-affected harmful factors
If known techniques are used to manage noise in clock trees, then voltage noise is reduced, but the response speed becomes too slow for modern integrated circuit devices
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the clock frequency parameter through a state machine that controls transitions between defined frequency states. Instead of using traditional slow noise management techniques, the system changes the frequency parameter in controlled steps, achieving both noise reduction and fast response suitable for modern integrated circuits operating at multiple GHz frequencies.
3Power
If clock trees operate at high frequencies with high power, then processing performance is improved, but noise from clock capacitance increases and interferes with component operation
Solution Approach 1:
The patent applies preliminary action by preparing the clock system for frequency transitions through a state machine that anticipates and controls the ramping process. Before achieving high frequency operation, the system progressively steps through intermediate frequency states, allowing the clock tree capacitance to charge and discharge in controlled increments. This preliminary staged approach enables high power operation at multiple GHz while reducing the harmful noise effects that would occur with abrupt frequency changes.
Data Source
AI summary
Methods, apparatus, and fabrication techniques relating to management of noise arising from capacitance in a clock tree of an integrated circuit. In some embodiments, the methods comprise receiving a signal to adjust a clock having a first rate to a second rate; and ramping, in response to receiving the signal, the clock from the first rate to the second rate, wherein the ramping comprises changing the frequency of the clock to at least one third rate between the first and second rates.