LED TUBE ADAPTED FOR USE WITH ELECTRONIC BALLAST

• US 20180146528A1
• Filed: 11/18/2016
• Published: 05/24/2018
• Est. Priority Date: 11/18/2016
• Status: Active Grant

• Current Assignee: Chung-Hung Yu, Wei-Jing Tseng
• Original Assignee: Chung-Hung Yu, Wei-Jing Tseng
• Inventors: Tseng, Wei-Jing, Yu, Chung-Hung
• Granted Patent: US 10,278,256 B2
• Time in Patent Office: Days
• CPC Class Codes: H05B 45/3578 Emulating the electrical or functional characteristics of discharge lamps
• CPC Class Codes: H05B 47/26 Circuit arrangements for protecting against earth faults
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An LED tube adapted for use with an electronic ballast is disclosed. The proposed LED tube includes a lossless filament simulation circuit having a first and a second output terminals and free from generating a power loss when the LED tube operated normally, wherein the lossless filament simulation circuit is electrically connected to the electronic ballast, and a bridge rectifier having a first and a second input terminals coupled to the first and the second output terminals respectively.

Claims

1. An LED tube adapted for use with an electronic ballast, comprising:

a lossless filament simulation circuit including;

a first and a second output terminals;

a first to a fourth capacitors; and

a first to a fourth resistors, wherein the electronic ballast has a first to a fourth ballast terminals, the first capacitor and the first resistor are electrically connected in parallel between the first ballast terminal and the first output terminal, the second capacitor and the second resistor are electrically connected in parallel between the first output terminal and the second ballast terminal, the third capacitor and the third resistor are electrically connected in parallel between the third ballast terminal and the second output terminal, and the fourth capacitor and the fourth resistor are electrically connected in parallel between the second output terminal and the fourth ballast terminal;

a bridge rectifier having a first and a second input terminals and a first and a second output terminals;

a current-limiting inductor electrically connected between the first output terminal of the lossless filament simulation circuit and the first input terminal of the bridge rectifier for limiting a current flowing through the electronic ballast;

a high-voltage prevention and isolation circuit having a fifth capacitor and a fifth resistor electrically connected in parallel between the second input terminal of the bridge rectifier and the second output terminal of the lossless filament simulation circuit;

an LED module circuit having a first and a second input terminals, wherein the first input terminal of the LED module circuit is electrically connected to the first output terminal of the bridge rectifier; and

a human body-leakage current isolation and high-voltage startup simulation circuit electrically connected between the second input terminal of the LED module circuit and the second output terminal of the bridge rectifier.

2. The LED tube according to claim 1, wherein the electronic ballast further includes a first lamp tube connector having the first ballast terminal and the second ballast terminal and a second lamp tube connector having the third ballast terminal and the fourth ballast terminal, the bridge rectifier includes a first to a fourth diodes, each of which has an anode and a cathode, the anode of the first diode is electrically connected to the cathode of the second diode and the first input terminal of the bridge rectifier, the anode of the third diode is electrically connected to the cathode of the fourth diode and the second input terminal of the bridge rectifier, and an AC signal received by the first and the second input terminals of the bridge rectifier becomes a DC signal after being rectified to drive the LED module circuit.

3. The LED tube according to claim 2, wherein the first to the fourth diodes are one of four fast diodes and four Schottky diodes, the human body-leakage current isolation and high-voltage startup simulation circuit includes a thyristor element, and the bridge rectifier and the human body-leakage current isolation and high-voltage startup simulation circuit are configured on a chip.

4. The LED tube according to claim 3, wherein the thyristor element is one selected from a group consisting of a DIAC, an SUS, an SIDAC, an SBS, an ASBS, an SAS, an SCR, a TRIAC and a zener diode, is able to receive an external signal so as to perform a switching control, and has a breakdown voltage to prevent the LED tube from becoming conductive before an input voltage reaches the breakdown voltage, protect the LED tube from burning out when mistakenly connected to one of an AC mains and an electronic ballast, and prevent a generation of a human body-leakage current when a 500 VAC AC mains frequency voltage test is performed, the high-voltage prevention and isolation circuit is used to cause a lamp tube current of the LED tube to be less than 100 mA when a withstanding high voltage test is performed while the first ballast terminal and the second ballast terminal of the first lamp tube connector are short-circuited and the third ballast terminal and the fourth ballast terminal of the second lamp tube connector are short-circuited.

5. The LED tube according to claim 4, wherein the high-voltage prevention and isolation circuit produces a high impedance at low frequency to prevent the LED tube from a break-down phenomenon and/or a flash-over phenomenon, and the current-limiting inductor is used for a self-oscillating ballast to change an impedance of a resonant tank of the electronic ballast so as to decrease the lamp tube current to adjust a lamp tube power.

6. The LED tube according to claim 1, wherein the electronic ballast is one selected from a group consisting of a rapid start electronic ballast, an instant start electronic ballast, a program start electronic ballast and a self-oscillating ballast, and the lossless filament simulation circuit simulates a filament impedance of a fluorescent lamp and is free from causing a loss in a circuit under a normal operation due to an extremely low high-frequency impedance of the first to the fourth capacitors.

7. An LED tube adapted for use with an electronic ballast, comprising:

a lossless filament simulation circuit including a first and a second output terminals, and electrically connected to the electronic ballast;

a bridge rectifier having a first and a second input terminals, wherein the first input terminal is coupled to the first output terminal of the lossless filament simulation circuit; and

a high-voltage prevention and isolation circuit having a capacitor and a resistor electrically connected in parallel between the second input terminal of the bridge rectifier and the second output terminal of the lossless filament simulation circuit.

8. The LED tube according to claim 7, further comprising a current-limiting inductor, a human body-leakage current isolation and high-voltage startup simulation circuit and an LED module circuit, wherein the bridge rectifier further includes a first and a second output terminals, the LED module circuit includes a first and a second input terminals, the first input terminal of the LED module circuit is electrically connected to the first output terminal of the bridge rectifier, the current-limiting inductor is electrically connected between the first output terminal of the lossless filament simulation circuit and the first input terminal of the bridge rectifier for limiting a current flowing through the electronic ballast, the human body-leakage current isolation and high-voltage startup simulation circuit includes a thyristor element electrically connected between the second input terminal of the LED module circuit and the second output terminal of the bridge rectifier, the thyristor element has a breakdown voltage to prevent the LED tube from becoming conductive before an input voltage reaches the breakdown voltage, protect the LED tube from burning out when mistakenly connected to one of an AC mains and an electronic ballast, and prevent a generation of a human body-leakage current when a 500 VAC AC mains frequency voltage test is performed, the capacitor is a fifth capacitor, the resistor is a fifth resistor, the high-voltage prevention and isolation circuit is used to cause a lamp tube current of the LED tube to be less than 100 mA when a withstanding high voltage test is performed while the first ballast terminal and the second ballast terminal of the first lamp tube connector are short-circuited and the third ballast terminal and the fourth ballast terminal of the second lamp tube connector are short-circuited, the lossless filament simulation circuit further includes a first to a fourth capacitors and a first to a fourth resistors, the electronic ballast has a first to a fourth ballast terminals, the first capacitor and the first resistor are electrically connected in parallel between the first ballast terminal and the first output terminal, the second capacitor and the second resistor are electrically connected in parallel between the first output terminal and the second ballast terminal, the third capacitor and the third resistor are electrically connected in parallel between the third ballast terminal and the second output terminal, and the fourth capacitor and the fourth resistor are electrically connected in parallel between the second output terminal and the fourth ballast terminal.

9. An LED tube adapted for use with a self-oscillating electronic ballast, comprising:

a lossless filament simulation circuit electrically connected to the electronic ballast and including a first output terminal;

a bridge rectifier including a first input terminal; and

a current-limiting inductor electrically connected between the first output terminal of the lossless filament simulation circuit and the first input terminal of the bridge rectifier, and limiting a current flowing through the self-oscillating electronic ballast.

10. The LED tube according to claim 9, further comprising a high-voltage prevention and isolation circuit, a human body-leakage current isolation and high-voltage startup simulation circuit and an LED module circuit, wherein the lossless filament simulation circuit further includes a second output terminal, the bridge rectifier further includes a second input terminal, the lossless filament simulation circuit further includes a first to a fourth capacitors and a first to a fourth resistors, the electronic ballast has a first to a fourth ballast terminals, the first capacitor and the first resistor are electrically connected in parallel between the first ballast terminal and the first output terminal, the second capacitor and the second resistor are electrically connected in parallel between the first output terminal and the second ballast terminal, the third capacitor and the third resistor are electrically connected in parallel between the third ballast terminal and the second output terminal, the fourth capacitor and the fourth resistor are electrically connected in parallel between the second output terminal and the fourth ballast terminal, the high-voltage prevention and isolation circuit includes a fifth capacitor and a fifth resistor, and the fifth capacitor and the fifth resistor are electrically connected in parallel between the second input terminal of the bridge rectifier and the second output terminal of the lossless filament simulation circuit.