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US 10,770,883 B2Granted
One-transistor devices for protecting circuits and autocatalytic voltage conversion therefor
AssigneeSympote Technologies LLC
InventorMark D. Creech
Life of this patent
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Abstract
Devices having one primary transistor, or a plurality of primary transistors in parallel, protect electrical circuits from overcurrent conditions. Optionally, the devices have only two terminals and require no auxiliary power to operate. In those devices, the voltage drop across the device provides the electrical energy to power the device. A third or fourth terminal can appear in further devices, allowing additional overcurrent and overvoltage monitoring opportunities. Autocatalytic voltage conversion allows certain devices to rapidly limit or block nascent overcurrents.
Claims18
A device for protecting a circuit having a primary current path from an overcurrent condition, comprising:
- a first terminal and a second terminal configured to route the primary current path through the device;
- a first transistor comprising a first gate, a first drain, and a first source;
- wherein the first transistor is a depletion mode, normally-on transistor;
- wherein the first transistor is arranged in series in the primary current path between the first terminal and the second terminal;
- a driver circuitry;
- the driver circuitry comprising a voltage converter circuitry adapted to receive an input voltage derived solely from a voltage between the first terminal and the second terminal, and convert the input voltage to a releasably-stored voltage,
- wherein the driver circuitry is configured to apply the releasably-stored voltage or a derivative voltage thereof as a gate voltage at the first gate relative to the first source,
- wherein the driver circuitry converts the input voltage to the releasably-stored voltage by multiplying and inverting the input voltage;
- and
- wherein the voltage converter circuitry comprises a switched capacitor network;
- wherein, when a first positive voltage and a normal current condition exist from the first terminal to the second terminal,
- the first transistor is configured to pass current between the first terminal and the second terminal;
- and
- wherein, when a second positive voltage and a severe overcurrent condition exist from the first terminal to the second terminal,
- the driver circuitry is configured to drive the first transistor into blocking depletion mode by applying the releasably-stored voltage or the derivative voltage thereof as the gate voltage;
- and
- wherein the device is configured to pass current during normal current conditions, and to substantially block current during severe overcurrent conditions.
14 more elements
A method for protecting a circuit against an overcurrent condition, comprising:
- providing a device having
- a first terminal and a second terminal, and
- a first transistor comprising a first gate, a first drain, and a first source;
- wherein the first transistor is a depletion mode, normally-on transistor;
- wherein the first transistor is arranged in series in a primary current path between the first terminal and the second terminal;
- wherein the device is configured to receive no auxiliary power;
- placing the first terminal and the second terminal in series electrical communication in the circuit so that all current flowing in the circuit flows through or is blocked by the device;
- when a non-zero voltage exists between the first terminal and the second terminal,
- converting the non-zero voltage to obtain a releasably-stored voltage;
- floating the releasably-stored voltage to obtain a floated voltage;
- when an overcurrent condition exists between the first terminal and the second terminal,
- applying the floated voltage to the first gate to drive the first transistor into blocking depletion mode,
- thereby blocking substantially all current between the first terminal and the second terminal;
- thereby protecting the circuit from the overcurrent condition.
11 more elements
A method for protecting a circuit against an overcurrent condition, comprising:
- providing a device having
- a first terminal and a second terminal, and
- a first transistor comprising a first gate, a first drain, and a first source;
- wherein the first transistor is a depletion mode, normally-on transistor;
- wherein the first transistor is arranged in series in a primary current path between the first terminal and the second terminal;
- wherein the device is configured to receive no auxiliary power;
- placing the first terminal and the second terminal in series electrical communication in the circuit so that all current flowing in the circuit flows through or is limited by the device;
- when a non-zero voltage exists between the first terminal and the second terminal,
- converting the non-zero voltage to obtain a releasably-stored voltage;
- floating the releasably-stored voltage to obtain a floated voltage;
- when an overcurrent condition exists between the first terminal and the second terminal,
- applying the floated voltage to the first gate to drive the first transistor into current limiting mode,
- thereby limiting the current between the first terminal and the second terminal;
- thereby protecting the circuit from the overcurrent condition.
11 more elements
Dependencies are inferred from the claim text.