US 4,902,958 A · Incandescent light regulation and intensity controller

Abstract

A regulation and intensity controller for prolonging the life of an incandescent lamp controls the root mean square voltage across the lamp by converting AC voltage to a DC voltage and by applying the DC voltage to the lamp through a switch and an inductor in series connection with the lamp. The switch is opened and closed according to a duty cycle that will produce a constant average voltage across the lamp. The switch is closed at fixed intervals and is opened by a circuit that is responsive to the instantaneous current through the lamp and to a voltage signal produced by integrating an error signal that represents the difference between the lamp voltage and a reference voltage. In this manner, the average voltage across the lamp is regulated and ripple is kept within a level such that the average voltage is a close representation of root mean square voltage. Additionally, the cycle-by-cycle current through the lamp is closely regulated.

Claims18

Dependent claims

A method of supplying electrical power from an alternating current power source to a lamp in a manner regulating the root mean square voltage across the lamp, comprising the steps of:

rectifying power from the power source to produce cyclically varying direct current power at a first voltage;
supplying said cyclically varying direct current power to a circuit branch including said lamp in electrical series connection with an inductor;
monitoring the voltage across the lamp, comparing said voltage with a reference to produce an error signal and integrating said error signal;
and
controlling the amount of said direct current applied to said lamp according to the value of said integrated error signal.

2 more elements

A regulating circuit for supplying electrical power from an alternating current power source to an incandescent lamp comprising:

a pair of outlet terminals configured for connection to opposite terminals of a lamp;
power source means for producing direct current power at a voltage between two output lines that is higher than the rated voltage of the lamp;
a switch between one of said output lines and one of said terminals;
an inductor between the other one of said output lines and the other one of said terminals;
a diode connected between said one of said terminals and said other one of said output lines and antiparallel said power source means;
voltage monitoring means for monitoring the voltage across said terminals and producing a lamp voltage control signal proportional to said voltage across said terminals;
control means for opening and closing said switch in response to said lamp voltage control signal at a duty cycle which causes the voltage across said terminals to have a predetermined average value, said control means including a reference voltage source and comparison means for comparing said lamp voltage control signal with said reference voltage and for producing an error signal proportional to the difference between said reference voltage and said lamp voltage control signal, said control means further including integrating means for integrating said error signal according to a predetermined closed loop time response.

4 more elements

A regulating circuit for supplying electrical power from an alternating current power source to an incandescent lamp comprising:

a pair of output terminals configured for connection to opposite terminals on a lamp;
rectifier means for rectifying alternating current from a power source;
voltage sensing means for producing a lamp voltage signal proportional to the value of the voltage across said output terminals;
current sensing means for producing a lamp current signal proportional to the current through said terminals;
voltage regulating means responsive to said lamp voltage signal for regulating the voltage across said terminals such that said voltage has a substantially constant average value, said voltage regulating means including comparison means for comparing said voltage signal with a reference to produce an error signal and integrating means for integrating said error signal according to a predetermined closed loop response time;
and
current regulating means responsive to said lamp current signal for regulating the value of said current within a particular range.

4 more elements

Dependencies are inferred from the claim text.

Incandescent light regulation and intensity controller

Life of this patent

Incandescent light regulation and intensity controller

Life of this patent

Abstract

Claims18