Low latency, broadband power-domain offset-correction signal level circuit implementation

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Solution Overview

Problem

Existing signaling techniques face challenges in communicating electrical signals between power domains due to voltage offsets, which can result in signal loss or distortion, especially for low-frequency content, and often require active circuits that introduce latency, making them unsuitable for applications with low-latency requirements.

Innovation Solution

An integrated circuit with a level-shifting circuit that includes a switched-capacitor low-pass filter and a passive high-pass filter, allowing for selective frequency passage and minimal latency level shifting between power domains, enabling the transmission of low-frequency content, including DC components, while maintaining waveform integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AC-coupling capacitor is used between power domains, then ground offset is addressed, but low-frequency content including DC is filtered out

Engineering Contradiction:

Improvesignal recoveryVSAvoidlow-frequency content

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the signal transmission path into two parallel channels: an AC-coupling path for high-frequency content and a DC-coupling path for low-frequency content including DC. This segmentation allows each path to be optimized for its specific frequency range, preventing the loss of low-frequency information while still addressing ground offset issues in the AC path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a level-shifting circuit as an intermediary component between the two power domains. This level-shifter compensates for ground offset by adjusting the voltage level of the signal, enabling reliable signal recovery at the receiver while preserving both AC and DC components of the original signal.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of information

If upconversion and downconversion are used, then low-frequency content can be transmitted, but propagation delay increases

Engineering Contradiction:

Improvelow-frequency contentVSAvoidpropagation delay

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent extracts the low-frequency content and DC components from the signal and transmits them through a dedicated DC-coupling path, separate from the AC-coupling path. This extraction eliminates the need for upconversion and downconversion operations, thereby removing the associated propagation delays while still preserving low-frequency information.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs dynamic switching between different coupling paths based on frequency content. High-frequency content is routed through the AC-coupling path, while low-frequency content and DC are routed through the DC-coupling path with level-shifting. This dynamic routing optimizes transmission speed for different frequency components.

Inventive Principle:

Principle #15Dynamics

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 solution allows for robust, low-latency communication of electrical signals across power domains with reduced distortion and power consumption, suitable for applications like USB 2.0 modules, and improves the reliability and cost-effectiveness of the interface circuit.

Implementation Method 1

a first filter that passes frequencies in the input electrical signal below a first corner frequency

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Implementation Method 2

a second filter, in parallel with the first filter, that passes frequencies in the input electrical signal above a second corner frequency

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Implementation Method 3

the first filter may include a switched-capacitor circuit, the second filter may include a passive filter

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 4

the switched-capacitor circuit may correct DC content in the input electrical signal for a difference between the first ground or reference voltage and the second ground or reference voltage

Methodology Applied

Scientific EffectVoltage offset correction:

Implementation Method 5

the level-shifting circuit combines outputs of the first filter and the second filter as the output electrical signal

Methodology Applied

Scientific EffectSignal combining:

Data Source

PatentUS11824530B2Low latency, broadband power-domain offset-correction signal level circuit implementation

Publication Date: 2023.11.21 AYDEEKAY LLC

AI summary

An interface circuit may convert an input electrical signal at an input node in a first power domain having a first ground or reference voltage into an output electrical signal at an output node in a second power domain having a second ground or reference voltage. Notably, a level-shifting circuit in the interface circuit may selectively electrically couple to the input node and the output node. Then, when there is electrical coupling, the level-shifting circuit may perform level shifting between the first power domain and the second power domain. The level shifting may involve: passing, using a first filter, frequencies in the input electrical signal below a first corner frequency; passing, using a second filter in parallel with the first filter, frequencies in the input electrical signal above a second corner frequency; and combining outputs of the first filter and the second filter as the output electrical signal.