{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-9638763","patent":{"patent_number":"US-9638763","title":"Resonant impedance sensing with a negative impedance control loop implemented with synchronized class D and output comparators","assignee":null,"inventors":[],"filing_date":"2014-12-30T00:00:00.000Z","publication_date":"2017-05-02T00:00:00.000Z","cpc_codes":["G01D"],"num_claims":20,"abstract":"A resonant impedance sensing system includes a negative impedance control loop incorporating the resonator as a loop filter, and including a class D negative impedance stage implemented with a class D comparator, and a loop control stage implemented with an output comparator clocked (D_clk) by the class D comparator. The class D comparator receives resonator oscillation voltage, and generates a class D switching output synchronized with resonator oscillation frequency. A discrete current source (such as a current DAC) drives the resonator through an H-bridge switched by the class D switching output, so that the time average of the discrete drive current corresponds to resonator oscillation amplitude. Based on resonator oscillation amplitude, the output comparator provides a discrete loop control signal to the discrete current source, driving the resonator with a negative impedance that balances resonant impedance, thereby maintaining constant resonator oscillation amplitude corresponding to steady-state oscillation."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Resonant impedance sensing with a negative impedance control loop implemented with synchronized class D and output comparators","description":"A resonant impedance sensing system includes a negative impedance control loop incorporating the resonator as a loop filter, and including a class D negative impedance stage implemented with a class D","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-9638763","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-9638763","citation_suggestion":"Patentable. \"Resonant impedance sensing with a negative impedance control loop implemented with synchronized class D and output comparators\" (US-9638763). https://patentable.app/patents/US-9638763","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-9638763","json":"https://patentable.app/api/llm-context/US-9638763","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-06-06T07:32:44.482Z"}