Bypass switch for in-line power steal
First Claim
1. An in-line thermostat power system comprising:
- a controllable bypass switch comprising a first line voltage metal-oxide-semiconductor field-effect transistor (MOSFET) and a second line voltage MOSFET, the controllable bypass switch receiving line voltage as an input;
a power stealing circuit receiving an output of the bypass switch as an input;
an energy storage circuit receiving an output of the power stealing circuit as an input;
a silicon controlled rectifier (SCR) interface circuit receiving an output of the energy storage circuit as an input; and
an SCR circuit receiving an output of the SCR interface circuit as an input.
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Accused Products
Abstract
A power supply unit for use with thermostats or other like devices. The power supply unit may keep electromagnetic interference emissions and harmonics at a minimum. A unit may have enough power for triggering a switch at about a cross over point of a waveform of input power to the unit. Power for triggering may come from a storage source. Power for the storage source may be provided with power stealing which require switching transistors which can generate emissions. In-line thermostats using MOSFETS power steal may do the power steal during an ON state (triac, relay or silicon controlled rectifier activated). Gate signals to the transistors may be especially shaped to keep emissions from transistor switching at a minimum. All that may be needed, during an OFF state as a bypass, is a high voltage controllable switch. The need may be achieved using high voltage MOSFETS.
442 Citations
21 Claims
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1. An in-line thermostat power system comprising:
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a controllable bypass switch comprising a first line voltage metal-oxide-semiconductor field-effect transistor (MOSFET) and a second line voltage MOSFET, the controllable bypass switch receiving line voltage as an input; a power stealing circuit receiving an output of the bypass switch as an input; an energy storage circuit receiving an output of the power stealing circuit as an input; a silicon controlled rectifier (SCR) interface circuit receiving an output of the energy storage circuit as an input; and an SCR circuit receiving an output of the SCR interface circuit as an input. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A thermostatic power supply mechanism comprising:
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a first terminal for connection of a power source; a second terminal for a connection to a load;
a bypass switch comprising an input directly connected to the first terminal, the bypass switch comprising one or more metal-oxide-semiconductor field-effect transistors (MOSFETs) that are switched;a silicon controlled rectifier (SCR) circuit comprising a first input connected to the first terminal, a second input for connection to a control signal, and an output terminal for a controlled line voltage for a load; a stealing circuit comprising an input connected to an output of the bypass switch, and an output connected to the second terminal, wherein the stealing circuit comprises an energy storage unit to store stolen power. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A power supply unit for a thermostat and electric heater comprising:
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a bypass switch circuit comprising an input directly connectable to a first line voltage, the bypass switch circuit comprises one or more metal-oxide-semiconductor field-effect transistor (MOSFET) switches; a power steal device comprising an input connectable to an output of the bypass switch circuit; an energy storage unit comprising an input connected to an output of the power steal device; and a silicon controlled rectifier (SCR) circuit comprising an input connectable to the first line voltage, and comprising an output for providing a controlled second line voltage. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification