US 5,705,896 AGranted

Control electronic ballast system using feedback

AssigneeSamsung Electronics Co., Ltd.

InventorNak Choon Choi

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Abstract

A feedback control system for electronic ballast comprises a lamp, an electronic ballast, a multiplier, a time controller, a first adder-subtracter, a reference voltage generator, a second adder-subtracter, an error amplifier, a capacitor, a voltage controlled current source VCCS, a third adder-subtracter and an oscilloscope and output driver.

Claims5

Dependent claims

An illumination device including an electronic ballast and a feedback control system, comprising:

a lamp;
an electronic ballast for controlling lamp preheating, temporary lamp discharge, and lamp discharge maintenance, and for producing first and second signals for controlling feedback;
a multiplier for receiving and multiplying said first and second signals from said electronic ballast, thereby producing an output signal;
a time controller for producing a signal proportional to a lamp preheating time period and a lamp discharge time period;
a soft start controller for receiving said signal from said time controller and producing an output signal controlling a lamp preheating period and a lamp discharge period, said soft start controller including:
a second transistor having a base terminal for receiving said signal from said time controller;
a first resistor having a first terminal connected to an emitter terminal of said second transistor;
a third transistor having a collector terminal connected to a second terminal of said first resistor, a base terminal arranged to receive an ip bias current, and an emitter terminal for producing a first current;
a fourth transistor having an emitter terminal connected to said second terminal of said first resistor and said collector terminal of said third transistor, and a collector terminal connected to said first adder-subtracter;
a second resistor having a first terminal connected to said collector terminal of said third transistor and to said emitter terminal of said fourth transistor;
a fifth transistor having an emitter terminal connected to a second terminal of the second resistor, a base terminal connected to a base terminal of the fourth transistor, and a collector terminal connected to said base terminal of said fifth transistor;
a fourth resistor having a first terminal connected to said emitter terminal of said third transistor, and a second terminal connected to said collector terminal of said fifth transistor;
a third resistor having a first terminal connected to said second terminal of said fourth resistor and said collector terminal of said fifth transistor;
and
a first transistor with an emitter terminal connected to a second terminal of said third resistor, a collector terminal, and a base terminal connected to said collector terminal of said first transistor, said collector terminal of said first transistor being arranged to pass a current to said collector terminal of said second transistor;
a first adder-subtracter for adding or subtracting said output signal from said multiplier and said output signal from said soft start controller;
a reference voltage generator for producing a reference voltage for determining an input voltage to said electronic ballast;
a second adder-subtracter for adding or subtracting an output signal produced by said first adder-subtracter passed through a resistor, and said reference voltage from said reference voltage generator;
an error amplifier for amplifying an output signal produced by said second adder-subtracter;
a capacitor for integrating an output current signal produced by said error amplifier so as to convert it into a voltage;
a voltage controlled current source (VCCS) for receiving said voltage from said capacitor and converting it into a current;
a third adder-subtracter for adding or subtracting said current from said VCCS, a reference current, and a signal produced by said electronic ballast passed through a resistor, thereby obtaining a resultant output current;
and
an oscillator and output driver including an internal capacitor which is arranged so as to be charged by an output current from said third adder-subtracter, thereby determining a control frequency supplied to said electronic ballast.

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Dependencies are inferred from the claim text.

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Abstract

An illumination device including an electronic ballast and a feedback control system, comprising:

a lamp;
an electronic ballast for controlling lamp preheating, temporary lamp discharge, and lamp discharge maintenance, and for producing first and second signals for controlling feedback;
a multiplier for receiving and multiplying said first and second signals from said electronic ballast, thereby producing an output signal;
a time controller for producing a signal proportional to a lamp preheating time period and a lamp discharge time period;
a soft start controller for receiving said signal from said time controller and producing an output signal controlling a lamp preheating period and a lamp discharge period, said soft start controller including:
a second transistor having a base terminal for receiving said signal from said time controller;
a first resistor having a first terminal connected to an emitter terminal of said second transistor;
a third transistor having a collector terminal connected to a second terminal of said first resistor, a base terminal arranged to receive an ip bias current, and an emitter terminal for producing a first current;
a fourth transistor having an emitter terminal connected to said second terminal of said first resistor and said collector terminal of said third transistor, and a collector terminal connected to said first adder-subtracter;
a second resistor having a first terminal connected to said collector terminal of said third transistor and to said emitter terminal of said fourth transistor;
a fifth transistor having an emitter terminal connected to a second terminal of the second resistor, a base terminal connected to a base terminal of the fourth transistor, and a collector terminal connected to said base terminal of said fifth transistor;
a fourth resistor having a first terminal connected to said emitter terminal of said third transistor, and a second terminal connected to said collector terminal of said fifth transistor;
a third resistor having a first terminal connected to said second terminal of said fourth resistor and said collector terminal of said fifth transistor;
and
a first transistor with an emitter terminal connected to a second terminal of said third resistor, a collector terminal, and a base terminal connected to said collector terminal of said first transistor, said collector terminal of said first transistor being arranged to pass a current to said collector terminal of said second transistor;
a first adder-subtracter for adding or subtracting said output signal from said multiplier and said output signal from said soft start controller;
a reference voltage generator for producing a reference voltage for determining an input voltage to said electronic ballast;
a second adder-subtracter for adding or subtracting an output signal produced by said first adder-subtracter passed through a resistor, and said reference voltage from said reference voltage generator;
an error amplifier for amplifying an output signal produced by said second adder-subtracter;
a capacitor for integrating an output current signal produced by said error amplifier so as to convert it into a voltage;
a voltage controlled current source (VCCS) for receiving said voltage from said capacitor and converting it into a current;
a third adder-subtracter for adding or subtracting said current from said VCCS, a reference current, and a signal produced by said electronic ballast passed through a resistor, thereby obtaining a resultant output current;
and
an oscillator and output driver including an internal capacitor which is arranged so as to be charged by an output current from said third adder-subtracter, thereby determining a control frequency supplied to said electronic ballast.

21 more elements