Clock-Synchronized Active Decoupling for Power Supply Noise
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Solution Overview
Problem
Integrated circuits face challenges in suppressing noise, particularly power and ground noise, due to simultaneous switching of outputs, which leads to voltage droop and propagation of noise through the system, and jitter caused by thermal noise or external interference, with existing solutions like passive components being limited in performance across a wide range of frequencies.
Innovation Solution
The method involves actively decoupling noise by shunting the supply voltage to a higher voltage and the ground voltage to a lower voltage, synchronously with the clock signal, using a switching circuit with low-resistance transistors controlled by a pulse generator to provide a stable local charge and minimize voltage droop, effectively stabilizing the power supply over a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive capacitors are used for noise suppression, then transient voltage amplitude is minimized, but performance degrades rapidly at frequencies above 100MHz due to parasitic inductance and resistance
Solution Approach 1:
The patent replaces static passive capacitors with dynamic active circuitry consisting of transistors and controlled current sources that can adapt their impedance characteristics in real-time to maintain effective noise suppression across a wide frequency range, overcoming the frequency limitations of passive components
Solution Approach 2:
The invention changes the operating parameters of the noise suppression mechanism by using controllable current sources and transistor switching to dynamically adjust the decoupling effect, allowing the system to maintain optimal performance across varying frequencies and operating conditions
2Productivity
If simultaneous switching of outputs is implemented to increase data transmission speed, then productivity increases, but large transient currents generate power and ground noise causing voltage droop and false switching
Solution Approach 1:
The patent applies preliminary action by proactively suppressing noise during the switching transient period using synchronized active decoupling circuits that are triggered in advance or in conjunction with the switching event, preventing voltage droop and ground bounce before they can propagate and cause false switching
Solution Approach 2:
The invention implements preliminary anti-action by introducing counteracting current sources that generate opposing transient currents to cancel out the harmful noise currents generated by simultaneous switching, thereby neutralizing the harmful effects before they impact circuit operation
3Productivity
If the number of drivers switching at the same time is increased to meet higher data demands, then productivity increases, but current draw on power supply increases causing voltage droop and noise propagation
Solution Approach 1:
The patent applies segmentation by dividing the power supply noise suppression function into multiple distributed active decoupling circuits, each serving specific drivers or circuit blocks, thereby localizing the power management and reducing the impact of simultaneous switching across the entire chip
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses transient noise and jitter, providing a stable power supply by actively decoupling noise synchronously with the clock signal, maintaining performance across a wide range of frequencies and temperatures, unlike passive devices which degrade rapidly.
Implementation Method 1
actively decoupling noise by shunting the supply voltage terminal to a higher voltage and the ground voltage terminal to a lower voltage
Implementation Method 2
using a switching circuit with low-resistance transistors controlled by a pulse generator to provide a stable local charge and minimize voltage droop
Data Source
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AI summary
A method of suppressing noise in a circuit (302) is disclosed. The method comprises providing a supply voltage (Vcc) to a first terminal (312) of the circuit; (302) providing a ground voltage to a second terminal (314) of the circuit; providing a clock signal to the circuit; and actively decoupling noise from at least one of the first terminal (312) and the second terminal (314) of the circuit (302) by actively decoupling noise synchronously with the clock signal. A circuit for suppressing noise in a circuit (302) is also disclosed.