EP0549589B1

EP0549589B1 - A flashing led lamp assembly

Info

Publication number: EP0549589B1
Application number: EP91912917A
Authority: EP
Inventors: Vivian Jude Amourgam
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-07-08
Filing date: 1991-07-08
Publication date: 1997-04-02
Anticipated expiration: 2011-07-08
Also published as: GB2239746B; EP0549589A1; GB9000478D0; CA2095730C; CA2095730A1; WO1993001570A1; GB2239746A; DE69125495D1

Abstract

A circuit comprising a flashing LED lamp assembly which is able to operate from various forms and types of sinusoidal or quasi sinusoidal a.c. signals and power sources with electrical voltages of up to 11,000 Volts and frequencies up to 100,000 Hertz applied at its input. The figure depicts the basic circuit.

Description

This invention relates to an electric circuit for driving in a practical manner and causing to flash on and off a bank of semi-conductor devices, commonly known as Light Emitting Diodes, (hereinafter referred to as LED's), by means of an alternating current and voltage, (hereinafter referred to as a.c. or a.c. power sources, or the mains), and operating with electrical voltages of upto 11,000 Volts and frequencies of upto 100,000 Hertz. The circuit and LED's together form a practical LED Flashing Lamp Assembly and includes a reactive element which is in series with the a.c. source.
When LED devices are driven from high voltage sources current limiting means must be provided to avoid destruction of the LED's. For a.c. voltage sources current limiting may be achieved using capacitors rather than the conventional means of using resistors. Such a reactive feed arrangement avoids excess heat dissipation and provides the LED's with the required drive current. When further voltage sensitive control of LED's is required, for example to flash a bank of LED's on and off by means of a voltage sensitive element such as an LED with a built in integrated circuit, additional voltage stabilisation is also required. When using reactive circuits in general but particularly when high voltage sources are involved discharging circuits and spike limiters must be provided. It is hoped that an innovation to provide:-

1. Drive current, with current limiting.
2. Voltage dropping without the associated heat dissipation and energy waste.
3. Voltage stabilisation to enable other, voltage sensitive, forms of electronics to be driven.
4. Discharging circuits and spike limiters to avoid personnel from getting a shock after removal of supply and to avoid damage to electronic circuits from external voltage surges.

Prior Art:

1. Portable safety device for attracting visual attention. (Figure 1). PCT International publication No. W0 90/14647.

This document discloses a flashing LED driving non-flashing LED's with a conventional resistor for current limiting means.
According to the present invention there is provided a flashing LED lamp assembly and control circuit including a reactive element, (Capacitor, C1) which element is in series with an a.c. source having a voltage upto 11,000 Volts and a frequency upto 100,000 Hertz, said assembly and circuit comprising 4 resistors, a metal oxide varistor, 2 capacitors, a zener diode, a flashing type LED with a built-in integrated circuit, (which causes the LED to flash), 2 power diodes, and an unspecified but finite number of LED's, (without a built-in flasher circuit), connected in series with the flashing LED. The whole lamp assembly and circuit being configured and arranged in accordance with figure 1.
Figure 1 shows a schematic circuit diagram of the preferred embodiment of the invention.
In the preferred embodiment the various circuit elements may have the following values:-

a) Zener diode Z1, 2 to 250 Volts, (upto 25 Watts).
b) Resistor R1, 0.01 Ohms to 10 million ohms.
c) Capacitor C1, 0.0000001 micro farads to 1 farad.
d) Capacitor C2, 0.001 micro farads to 1 farad.
e) Resistor R3, 1.0 Ohm to 10 million ohms.
f) Resistor R2, 1.0 Ohm to 10 million Ohms.

Also,

1. The relative position of R4 and C1 may be reversed without effecting the operation of the circuit.
2. The total number of non flashing LED's may range in number from 1 to 5500.

According to the present invention the salient points of the circuit described are as follows:-

1. Identification of the fact that it is the flashing LED which causes the other non-flashing LED's, which are connected in series with the flashing LED, to flash, with current limiting means provided elsewhere.
2. The incorporation of resistor R1 connected across the flashing and non-flashing LED assembly.

In the context of the following claims and the rest of this application the term "reactive" is to be interpreted in the Electrical Engineering or as defined in the Physics manner, that is to say as one would discuss "real" power and "reactive" power in the Electrical Engineering or Physics domain and to give the word "reactive" its Electrical Engineering or Physics meaning.

Claims

A flashing LED lamp assembly and control circuit including a reactive element (C1) in which the said reactive element is connected in series with a first a.c. power supply terminal having a voltage upto 11,000 Volts and a frequency upto 100,000 Hertz; one side of a fourth resistor, (R4), is connected in series with the said reactive element with the other side of the said fourth resistor connected to a first circuit node; the anode side of a second power diode, (D2), is connected to the said first circuit node with the cathode side of the said second diode connected to the second a.c. power supply terminal; a second resistor, (R2), connected between the said first a.c. power supply terminal and the second a.c. power supply terminal; a metal oxide varistor connected between the said first a.c. power supply terminal and the second a.c. power supply terminal; the cathode side of a first power diode, (D1), connected to the said first circuit node and the anode side of the said first power diode connected to a second circuit node; the anode side of a first zener diode, (Z1), connected to the said second circuit node; the cathode side of the said first zener diode connected to a third circuit node, (R); the anode of a flashing LED, (with a built-in integrated circuit), connected to the said third circuit node; the cathode side of the said flashing LED connected to a fourth circuit node, (S); the anode side of a bank of one or more ordinary LED's connected in series and in cathode to anode configuration and in series with the cathode side of the said flashing LED and with the said fourth circuit node; the cathode side of the said bank of LED's connected to the said second circuit node; a first resistor, (R1), connected between the said third circuit node and the said second circuit node; a third resistor, (R3), connected between the said third circuit node and the second a.c. supply terminal; the positive connection of a second polarised capacitor, (C2), connected to the second a.c. supply terminal; the negative connection of the said second capacitor connected to the said second circuit node.
A flashing LED lamp assembly and circuit as claimed in claim 1 wherein the said first zener diode, (Z1), depicted may range in value from 2 Volts to 250 Volts and rated upto 25 Watts.
A flashing lamp assembly and circuit as claimed in claim 1 wherein the said first resistor, (R1), depicted may range in value from 0.01 Ohm to 10 Million Ohms.
A flashing LED lamp assembly and circuit as claimed in claim 1 wherein the said reactive element, (capacitor C1), depicted may range in value from 0.0000001 micro farad to 1 farad.
A flashing LED lamp assembly and circuit as claimed in claims 1 and 2 and 3 and 4 wherein the relative positions of the said fourth resistor, (R4), and the said reactive element, (Capacitor C1), are reversed.
A flashing LED lamp assembly and circuit as claimed in claims 1 and 2 and 3 and 4 and 5 wherein the total number of non flashing LED's connected in series with the said flashing LED may range in number from 1 to 5500.
A flashing LED lamp assembly and circuit as claimed in claim 1 wherein the said second capacitor, (C2), may range in value from 0.001 micro farad to 1 farad.
A flashing LED lamp assembly and circuit as claimed in claim 1 wherein the said third resistor, (R3), may take any value betweeen 1 Ohm and 10 Million Ohms.
A flashing LED lamp assembly and circuit as claimed in claim 1 wherein the said second resistor, (R2), may take any value between 1 Ohm and 10 Million Ohms.
A flashing LED lamp assembly and circuit as claimed in claims 1 - 9 wherein a fifth resistor which may take any value between 1 micro ohm and 150 million ohms and is or may be connected between the said third circuit node and the said fourth circuit node.
A flashing LED lamp assembly and circuit as claimed in claim 10 wherein a first thermistor and in particular a self-heating current limiting thermistor is placed in series with the said fifth resistor and where the combination, (resistor and thermistor), is or may be connected between the said third circuit node and the said fourth circuit node.
A flasing LED lamp assembly and circuit as claimed in claims 10 and 11 wherein the said first thermistor is placed in series with the said fifth resistor and with a second similar thermistor and where the series combination, (thermistor and resistor and thermistor), is or may be connected between the said third circuit node and the said fourth circuit node.