{
    "title": "Fast-Charging Circuit",
    "inventor_name": "Masayoshi KANNO",
    "publication_year": null,
    "device_name": "Charging circuit with step-down converter and current controller",
    "goal": "Efficiently charge a secondary battery (e.g., EV battery) in a very short time (approximately five minutes).",
    "problem_addressed": "Long charging times for electric vehicles and inefficiency caused by impedance mismatch between generator output and battery load.",
    "concept_summary": "The invention uses a generator (e.g., a small-sized manual or motor-driven generator) whose high-voltage, low-current output is stepped down by a DC-DC converter to a low-voltage, high-current supply for the battery. A current controller adjusts the charging current based on the amount of electricity generated, while a mode selector lets the user choose between a current-preferred or efficiency-preferred charging mode. A monitor circuit tracks stored energy by multiplying current and time.",
    "detailed_description": "The patented charging circuit comprises: (1) a generator that produces an output voltage; (2) a step-down circuit (DC-DC converter) that reduces this voltage to a predetermined level; (3) a current controller that regulates the charging current supplied to a secondary battery based on the generated electricity; (4) a mode selector that switches between a current-preferred mode (maximizing current) and an efficiency-preferred mode (maximizing power utilization); and (5) a monitor circuit that detects stored electricity by multiplying charging current by charging time. The step-down circuit receives the generator output at high voltage and low current, then delivers low voltage and high current to the battery, achieving impedance matching regardless of the generator's internal resistance. The coil of the generator may be delta-connected to lower output resistance. This architecture enables rapid charging (e.g., five-minute recharge of a Nissan Leaf or Tesla Roadster) while allowing low-noise, low-speed motor operation.",
    "category": "Electromagnetism & Magnetism",
    "principles": [
        "Impedance matching",
        "DC-DC step-down conversion",
        "Current control based on generated energy",
        "Mode selection (current-preferred vs efficiency-preferred)",
        "Energy monitoring (current x time)"
    ],
    "scientific_domains": [
        "Electrical Engineering",
        "Power Electronics",
        "Energy Storage"
    ],
    "mechanisms_of_action": [
        "Step-down converter reduces generator voltage",
        "Current controller adjusts charging current",
        "Mode selector chooses charging strategy",
        "Monitor circuit calculates stored energy"
    ],
    "materials": [
        "Copper wire (coil)",
        "Semiconductor devices (transistors, diodes)",
        "Resistors",
        "Capacitors"
    ],
    "energy_sources": [
        "Mechanical rotation (human or motor)",
        "Generator electricity"
    ],
    "inputs": [
        "Mechanical effort (rotation)",
        "Generator output voltage",
        "Battery voltage"
    ],
    "outputs": [
        "Charged secondary battery",
        "Stored electricity amount"
    ],
    "claimed_performance": "Device can recharge a Nissan LEAF or Tesla Roadster in about five minutes by delivering high-voltage, low-current generator power to a low-voltage, high-current charging stage.",
    "experimental_evidence": null,
    "replication_status": null,
    "keywords": [
        "fast charging",
        "EV charger",
        "step-down converter",
        "impedance matching",
        "manual generator",
        "mode selector"
    ],
    "related_technologies": [
        "DC-DC converters",
        "Battery management systems",
        "Portable manual chargers"
    ],
    "controversy_level": "low",
    "confidence_score": 0.8,
    "practicability_score": 0.6,
    "fringe_score": 0.1,
    "evidence_strength": 0.2,
    "risk_score": 0.1,
    "trl_estimate": 5,
    "source_urls": [
        "http://green.autoblog.com/2011/06/09/japanese-developer-patents-5-minute-plug-in-vehicle-charger/"
    ],
    "organizations": [
        "Sony Corp"
    ],
    "applications": [
        "Electric-vehicle rapid charging stations",
        "Portable manual chargers for small batteries",
        "Emergency power generation for mobile devices"
    ],
    "limitations": [
        "Charging speed depends on generator size and user effort",
        "Maximum power limited by generator's internal resistance",
        "Integration with existing EV battery management may require additional control logic"
    ],
    "open_questions": [
        "What is the real-world charging time for a full-size EV battery under typical human power input?",
        "How does the system perform over long-term operation and durability?",
        "What are the cost implications of the step-down converter and control electronics at scale?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "He has apparently patented a device that can recharge a Nissan LEAF or Tesla Roadster in about five minutes.",
        "The step-down circuit receives an output of the generator, in charging, at a high voltage and a small current and is used to charge the battery at a low voltage and a large current.",
        "A charging circuit includes a generator, a step-down circuit for reducing an output voltage of the generator to a predetermined voltage, a current controller for controlling a charging current, which is supplied from the step-down circuit to a secondary battery, based on an amount of power generated by the generator.",
        "The mode includes a current-preferred mode for maximizing the charging current supplied to the battery and an efficiency-preferred mode for maximizing utilization of power taken out of the generator.",
        "A monitor circuit for monitoring an amount of stored electricity... detecting the amount of stored electricity by multiplying the charging current and a charging time."
    ]
}