Power supply and control circuit for series connected controller
First Claim
1. In a DC power supply and control circuit including a pair of AC input terminals to be connected across and energized from one AC power line and one conductor extending to one terminal of a load device whose other terminal is to be connected to another AC power line, said AC power lines being the source of an applied AC voltage to energize and operate the power supply and control circuit and load device, said power supply and control circuit further including a triggerable power conducting power switch having a pair of load terminals coupled to said AC input terminals and a control terminal for receiving a trigger signal which triggers said power switch into a conductive state which continues until current flow therethrough drops below a given holding current level during the half cycle of the applied AC voltage involved;
- and controller means for effecting operation of said power switch either in a non-conductive mode where the switch is continuously non-conductive or in a conductive mode where the switch is conductive repeatedly for a portion of the half cycles involved which begin after the beginning of the half cycles involved, said controller means during the conductive mode of operation of said switch generating a power switch triggering control signal fed to said control terminal of said power switch which signal causes conduction thereof a short time interval after the AC voltage applied to said power switch load terminals passes through zero;
the improvement comprising a DC power supply circuit for energizing said controller means, said DC power supply circuit being coupled across said AC input terminals so that the circuit is shunted by said switch when the switch is conducting, said DC power supply circuit including energy storing means which is coupled to said controller means to energize the same, anda series circuit for feeding current to said energy storing means from said pair of AC input terminals, said series circuit including rectifier means for converting AC to DC and a relatively large impedance connected in series with said rectifier means and energy storing means, said impedance means being of such a greater magnitude than the impedance of said load device that only a small amount of power compared to the normal load power is drawn by said power supply circuit when said power switch is continuously non-conductive, and means operative only during the conductive mode of operation of the power switch for shunting said impedance means with a low impedance during the short intervals at the beginning of the half cycle conducting periods of the power switch when said power switch is still non-conductive so that said energy storing means is rapidly charged to permit conduction of said power switch starting at a low value of the applied AC voltage.
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Accused Products
Abstract
A control circuit for a power switch like a triac to be connected in series with a load device, at a situs where only one AC power conductor and a conductor extending to the load device is available, is energized from a DC power supply energized from these conductors. The power supply includes at least one rectifier connected in series with a capacitor, the terminals of which capacitor constitute the DC output terminal of the DC power supply, an impedance of much greater resistance than that of the load device and through which the capacitor is charged when the triac is in its non-conductive mode, and a normally non-conductive triggerable low impedance threshold device shunting the high impedance and triggered momentarily into conduction as the applied AC voltage goes through zero when the triac is to be in its conductive mode. Current flow through this threshold device triggers the power switch into conduction a short interval after passage of this voltage through zero. The capacitor charges only during each such short interval it takes to initiate conduction of the power switch.
48 Citations
17 Claims
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1. In a DC power supply and control circuit including a pair of AC input terminals to be connected across and energized from one AC power line and one conductor extending to one terminal of a load device whose other terminal is to be connected to another AC power line, said AC power lines being the source of an applied AC voltage to energize and operate the power supply and control circuit and load device, said power supply and control circuit further including a triggerable power conducting power switch having a pair of load terminals coupled to said AC input terminals and a control terminal for receiving a trigger signal which triggers said power switch into a conductive state which continues until current flow therethrough drops below a given holding current level during the half cycle of the applied AC voltage involved;
- and controller means for effecting operation of said power switch either in a non-conductive mode where the switch is continuously non-conductive or in a conductive mode where the switch is conductive repeatedly for a portion of the half cycles involved which begin after the beginning of the half cycles involved, said controller means during the conductive mode of operation of said switch generating a power switch triggering control signal fed to said control terminal of said power switch which signal causes conduction thereof a short time interval after the AC voltage applied to said power switch load terminals passes through zero;
the improvement comprising a DC power supply circuit for energizing said controller means, said DC power supply circuit being coupled across said AC input terminals so that the circuit is shunted by said switch when the switch is conducting, said DC power supply circuit including energy storing means which is coupled to said controller means to energize the same, anda series circuit for feeding current to said energy storing means from said pair of AC input terminals, said series circuit including rectifier means for converting AC to DC and a relatively large impedance connected in series with said rectifier means and energy storing means, said impedance means being of such a greater magnitude than the impedance of said load device that only a small amount of power compared to the normal load power is drawn by said power supply circuit when said power switch is continuously non-conductive, and means operative only during the conductive mode of operation of the power switch for shunting said impedance means with a low impedance during the short intervals at the beginning of the half cycle conducting periods of the power switch when said power switch is still non-conductive so that said energy storing means is rapidly charged to permit conduction of said power switch starting at a low value of the applied AC voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- and controller means for effecting operation of said power switch either in a non-conductive mode where the switch is continuously non-conductive or in a conductive mode where the switch is conductive repeatedly for a portion of the half cycles involved which begin after the beginning of the half cycles involved, said controller means during the conductive mode of operation of said switch generating a power switch triggering control signal fed to said control terminal of said power switch which signal causes conduction thereof a short time interval after the AC voltage applied to said power switch load terminals passes through zero;
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9. In a DC power supply and control circuit including a pair of AC input terminals connected across and energized from one AC power line and one conductor extending to one terminal of a load device whose other terminal is connected to another AC power line, said AC power lines being the source of an applied AC voltage to energize and operate the power supply and control circuit and load device, said power supply and control circuit further including a triggerable power switch having a pair of load terminals coupled to said AC input terminals and a control terminal for receiving a triggering signal which triggers said power switch into a conductive state which continues until current flow therethrough drops below a given holding current level during the half cycle of the applied AC voltage involved;
- the improvement comprising controller means for effecting operation of said power switch either in a non-conductive mode where the switch is continuously non-conductive or in a conductive mode where the switch is conductive repeatedly for a portion of the half cycle involved which begin after the beginning of the half cycle involved, said controller means during the conductive mode of operation of said switch generating a power switch triggering control signal fed to said control terminal of said power switch which signal causes conduction thereof a short time interval after the AC voltage applied to said power switch load terminals passes through zero;
a DC power supply circuit for energizing said controller means, said DC power supply circuit being coupled across said AC input terminals so that the circuit is shunted by said switch when the switch is conducting, said DC power supply circuit comprising a parallel branch impedance circuit connected in series with an energy storing means which supplies energizing DC to said controller means and rectifier means between said AC input terminals, said rectifier means limiting current flow in one direction through said energy storing means, said parallel branch impedance circuit comprising a relatively large impedance of such a greater magnitude than the impedance of said load device that only a small amount of power compared to the normal load power is drawn by said energy storing means when said power switch is continuously non-conductive, said parallel branch impedance circuit having a normally non-conducting branch in parallel with said relatively large impedance and switchable into a highly conductive relatively low impedance state to effect the rapid feeding of current to said energy storing means; and
said controller means including means operative only during the conductive mode of operation of the power switch for switching said normally non-conductive branch to said highly conductive state at or shortly after the instantaneous value of the AC voltage present across said AC input terminals passes through zero and before said power switch can be triggered into conduction so that said energizing storage means is rapidly charged to permit conduction of said power switch starting at a low value of the applied AC voltage. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
- the improvement comprising controller means for effecting operation of said power switch either in a non-conductive mode where the switch is continuously non-conductive or in a conductive mode where the switch is conductive repeatedly for a portion of the half cycle involved which begin after the beginning of the half cycle involved, said controller means during the conductive mode of operation of said switch generating a power switch triggering control signal fed to said control terminal of said power switch which signal causes conduction thereof a short time interval after the AC voltage applied to said power switch load terminals passes through zero;
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17. A DC power supply and control circuit comprising:
- a pair of AC input terminals to be connected across and energized from one AC power line and one conductor extending to one terminal of a load device whose other terminal is to be connected to another AC power line;
a triggerable power threshold switch having a pair of load terminals coupled to said AC input terminals and a control terminal for receiving a trigger signal which triggers said power switch into a conductive state which continues until current flow therethrough drops below a given holding current level during a half cycle of the applied AC voltage involved;
control means for selectively providing or terminating a control signal which is to initiate a conductive mode of operation of said power threshold switch;
a DC power supply circuit for said control means for energizing the same, said DC power supply circuit being coupled across said AC input terminals so that the circuit is shunted by said switch when the switch is conducting, said DC power supply circuit including a chargeable energy storing means having output terminals at which appears the DC voltage to which the storing means charges, said output terminals being coupled to said control means to energize the same, a circuit for feeding charging current to said energy storing means from said pair of AC input terminals, said circuit including rectifier means for converting AC to DC and a relatively large impedance means connected in series with said rectifier means and energy storing means and through which said energy storing means charges when said power threshold switch is operated in a non-conductive mode, shunting means for providing a low impedance during short intervals at the beginning of the half cycle conducting periods of the power threshold switch operating in a conductive mode before the switch is triggered into conduction, said shunting means being a threshold device having load terminals in parallel with said large impedance means and a control terminal, and switch means selectively operable by said control means to feed a triggering signal to the control terminal of said shunting threshold device at least at or near the beginning of each half cycle of the applied AC voltage when the power threshold switch is to be operated in its conductive mode; and
power switch triggering means following the conduction of said shunting threshold device each such half cycle for generating a triggering signal fed to the control terminal of said power threshold switch to trigger the same into conduction each such half cycle shortly after said shunting threshold device becomes conducting, said energy storing means then being charged by current flowing through the shunting threshold device prior to the initiation of conduction of said power threshold switch every such half cycle of the applied AC voltage so that said energizing storage means is rapidly charged to permit conduction of said power switch starting at a low value of the applied AC voltage.
- a pair of AC input terminals to be connected across and energized from one AC power line and one conductor extending to one terminal of a load device whose other terminal is to be connected to another AC power line;
Specification