LDO Regulator Current Cancellation for Shared Supply Noise
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Solution Overview
Problem
Increased clock signal frequencies in electronic devices cause noise and aggressor currents, leading to interference between different types of circuits sharing a power supply, which can be mitigated by using a low-dropout (LDO) regulator with current cancellation techniques.
Innovation Solution
A power supply circuit incorporating a current replicator, polarity flipper, and current mirror to replicate and reverse the polarity of aggressor currents, thereby canceling or reducing their impact on the power supply node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple different types of electronic circuits share a single power supply bump or solder ball, then the number of external connections is reduced and device size is minimized, but noise is introduced into other circuits
Solution Approach 1:
The patent extracts the harmful aggressor current from the shared power supply node by using a current replicator to detect it, a polarity flipper to invert its polarity, and a current mirror to inject the inverted current, thereby removing the noise impact on other circuits while maintaining the compact shared power supply structure
2Speed
If clock signal frequency is increased to achieve higher operating speeds, then processing speed is improved, but noise at various nodes increases and adversely impacts other circuits
Solution Approach 1:
The patent implements a feedback mechanism where the current replicator continuously monitors the aggressor current generated by high-speed clock operations, and the polarity flipper and current mirror dynamically inject counter-current to cancel the noise, allowing high operating speeds to be maintained without adverse noise impacts
3Area of stationary object
If the distance between different types of electronic circuits is reduced, then device area is minimized, but inductive coupling increases and introduces noise
Solution Approach 1:
The patent converts the harmful inductive coupling effect into a beneficial cancellation mechanism by using the aggressor current detection to generate an equal and opposite current through the polarity flipper and current mirror, thereby neutralizing the noise that would otherwise result from reduced circuit spacing
Data Source
AI summary
Techniques and apparatus for supplying power with aggressor current attenuation are provided. One example power supply circuit generally includes a low-dropout (LDO) regulator including an input coupled to a power supply node and an output coupled to a load circuit; a current replicator coupled to the output of the LDO regulator and configured to replicate a scaled version of an aggressor current to generate a fractional aggressor current; a current-steering circuit coupled to the current replicator and configured to replicate and reverse a polarity of the fractional aggressor current to generate a reversed fractional aggressor current; and a current mirror including an input coupled to the current-steering circuit and an output coupled to the power supply node, the current mirror being configured to sink an aggressor adjustment current from the power supply node based on the reversed fractional aggressor current.