Active triac triggering circuit
First Claim
1. A power supply unit for a heating, ventilation and air conditioning thermostat, comprising:
- a first terminal for connection to a line of a power source;
a second terminal for connection to a load;
a bypass circuit having an input connected to the first terminal;
a triac having an input connected to the first terminal;
a stealing circuit having an input connected to an output of the bypass circuit and having a first output connected to the second terminal;
a power steal module having an input connected to an output of the triac;
a trigger circuit having an output connected to a second input of the triac;
a DC-DC converter connected to a second output of the stealing circuit; and
wherein the second output of the stealing circuit is connected to a second input of the trigger circuit.
3 Assignments
0 Petitions
Accused Products
Abstract
A power supply unit for use with thermostats or other like devices requiring power. A power supply unit may be designed to keep electromagnetic interference emissions at a minimum, particularly at a level that does not violate governmental regulations. A unit may be designed so that there is enough power for a 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 rather than line power to reduce emissions on the power line. Power for the storage source may be provided with power stealing. Power stealing may require switching transistors which can generate emissions. Gate signals to the transistors may be especially shaped to keep emissions from transistor switching at a minimum.
426 Citations
18 Claims
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1. A power supply unit for a heating, ventilation and air conditioning thermostat, comprising:
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a first terminal for connection to a line of a power source; a second terminal for connection to a load; a bypass circuit having an input connected to the first terminal; a triac having an input connected to the first terminal; a stealing circuit having an input connected to an output of the bypass circuit and having a first output connected to the second terminal; a power steal module having an input connected to an output of the triac; a trigger circuit having an output connected to a second input of the triac; a DC-DC converter connected to a second output of the stealing circuit; and wherein the second output of the stealing circuit is connected to a second input of the trigger circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A power system for thermostats, comprising:
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a first terminal connected to a line of a power supply; a bypass circuit having an input connected to the first terminal; a triggerable switch having an input connected to the first terminal; a power steal module having an input connected to an output of the bypass circuit; a zero crossover detector having an input connected to an output of the bypass circuit; an energy storage module having an input connected to an output of the power steal module; and a trigger circuit having an input connected to an output of a zero crossover detector and having an output connected to a second input of the triggerable switch; and wherein; the trigger circuit comprises a processor; the processor has an input connected to the output of the zero crossover detector and an output connected to the second input of the triggerable switch; the power steal module steals power from the first terminal or an output of the bypass circuit; and the power steal module provides stolen power to the energy storage module. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A thermostat power system comprising:
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a triggerable switch having an input connected to a first terminal; a bypass circuit having an input connected to the first terminal; an energy storage module having an input connected to an output of the bypass circuit and an output connected to a second terminal; a power steal circuit having an input connected to an output of the triggerable switch; and an active trigger module having an input connected to an output of a wave position detector, having an output connected to the triggerable switch, and having an input connected to a second output of the energy storage module; and wherein; the first terminal and second terminal are for connection to an AC power line and load arrangement; the power steal circuit comprises transistors; a trigger signal is sent at certain times, according to information at the output of the wave position detector, from the output of the active trigger module to a second input of the triggerable switch; and a signal from the output of the triggerable switch to the input of the power steal circuit turns the transistors on or off; and wherein the active trigger module takes energy at the second input from the second output of the energy storage to trigger the triggerable switch near a zero crossing of the power line when energy directly from the power line is insufficient to trigger the triggerable switch.
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15. A power supply unit for a heating, ventilation and air conditioning thermostat, comprising:
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a first terminal for connection to a line of a power source; a second terminal for connection to a load; a bypass circuit having an input connected to the first terminal; a triac having an input connected to the first terminal; a stealing circuit having an input connected to an output of the bypass circuit and having a first output connected to the second terminal; a power steal module having an input connected to an output of the triac; a trigger circuit having an output connected to a second input of the triac; a linear regulator connected to a second output of the stealing circuit; and wherein the second output of the stealing circuit is connected to a second input of the trigger circuit. - View Dependent Claims (16)
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17. A power supply unit for a heating, ventilation and air conditioning thermostat, comprising:
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a first terminal for connection to a line of a power source; a second terminal for connection to a load; a bypass circuit having an input connected to the first terminal; a triac having an input connected to the first terminal; a stealing circuit having an input connected to an output of the bypass circuit and having an output connected to the second terminal; a power steal module having an input connected to an output of the triac; a trigger circuit having an output connected to a second input of the triac; a zero crossing detection circuit having an input connected to the first terminal; and an interface circuit having an input connected to an output of the zero crossing detection circuit and having an output connected to an input of the trigger circuit; and wherein; a second output of the stealing circuit is connected to a second input of the trigger circuit; the trigger circuit comprises; a DC-DC negative current source having an input connected to the second output of the stealing circuit; and a triac gate triggering signal circuit having an input connected to an output of the DC-DC negative current source a zero crossing signal goes from the zero crossing detection circuit to the input of the interface circuit; and a zero crossing drive signal goes from the output of the interface circuit to the input of the trigger circuit. - View Dependent Claims (18)
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Specification