Offset-Compensating Circuit for Contact Lens Phase Lock

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Solution Overview

Problem

In electronic contact lenses, the leakage current from the phase-locked loop can overpower the Costas loop charge pump, preventing the Costas loop from locking and maintaining phase alignment with the carrier signal.

Innovation Solution

An offset-compensating circuit is introduced to supply an offsetting current to the capacitor, partially canceling the leakage current from the phase-locked loop and allowing the Costas loop to maintain phase lock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the phase-locked loop is used during lock acquisition to stabilize the voltage-controlled oscillator, then the phase alignment circuit can generate a relatively stable error signal, but the leakage current from the phase-locked loop overpowers the Costas loop charge pump, preventing the Costas loop from locking

Engineering Contradiction:

Improvephase lock stabilityVSAvoidleakage current

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful leakage current from the phase-locked loop into a beneficial effect by introducing an offset-compensating circuit that deliberately injects an equal and opposite current. This compensating current cancels the leakage current, allowing the Costas loop charge pump to function properly and achieve phase lock despite the presence of the leakage current from the phase-locked loop.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The offset-compensating circuit acts as an intermediary between the phase-locked loop and the Costas loop charge pump. It mediates the interaction by introducing a compensating current that counteracts the harmful leakage current, enabling the Costas loop to lock without directly modifying the phase-locked loop or the charge pump themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the phase-locked loop is disabled and control of the voltage-controlled oscillator is performed by the phase-alignment circuit, then the Costas loop can maintain phase lock, but the leakage current from the phase-locked loop still prevents the Costas loop from locking

Engineering Contradiction:

Improvecontrol simplicityVSAvoidphase lock acquisition

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent converts the harmful leakage current into a manageable parameter by introducing the offset-compensating circuit. This allows the system to operate with the phase-locked loop disabled and simple phase-alignment circuit control, while the compensating circuit actively counteracts the leakage current to enable successful phase lock acquisition.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the Costas loop charge pump is used to maintain phase alignment, then the radio receiver can achieve stable operation, but the charge pump is overpowered by leakage current from the phase-locked loop, preventing it from functioning

Engineering Contradiction:

Improveradio receiver stabilityVSAvoidcharge pump current

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The offset-compensating circuit introduces a counterweight current that opposes and cancels the leakage current from the phase-locked loop. This counteracting current restores the balance in the capacitor node, allowing the Costas loop charge pump to maintain phase alignment without being overpowered by the leakage current.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent transforms the harmful leakage current that overpowers the charge pump into a compensated parameter. By deliberately injecting an equal and opposite current through the offset-compensating circuit, the system neutralizes the harmful effect and enables the charge pump to function as intended for maintaining phase lock.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12313912B2Electronic contact lens data receiver circuit

Publication Date: 2025.05.27 TECTUS CORP

AI summary

An electronic contact lens. In some embodiments, the electronic contact lens includes: a receiver, including: a voltage-controlled oscillator; a phase-alignment circuit, connected to a control input of the voltage-controlled oscillator; and an offset-compensating circuit, connected to the control input of the voltage-controlled oscillator, the receiver being configured: to operate in: a calibration mode, or an operating mode; and to select, in the calibration mode, an operating-mode setting of the offset-compensating circuit, the selecting including: adjusting the offset-compensating circuit, and monitoring an output frequency of the voltage-controlled oscillator.