WO2016058592A1

WO2016058592A1 - Circuit for the grid-compatible operation of light-emitting diodes, as well as lighting means and lights

Info

Publication number: WO2016058592A1
Application number: PCT/DE2015/100411
Authority: WO
Inventors: Uwe Wiesner; Norbert Wittschief
Original assignee: Atlas Elektronik Gmbh
Priority date: 2014-10-14
Filing date: 2015-10-02
Publication date: 2016-04-21
Also published as: DE102014114851A1

Abstract

The invention relates to a circuit for operating light-emitting diodes in a grid-compatible manner, said circuit comprising: n LED chains each having a particular ordinal number N, n being an integer greater than 1 and N being an integer greater than 0; an overall supply voltage connection to which a time-dependent supply voltage, particularly a rectified AC voltage, can be applied; and an LED chain connection which is configured such that as the supply voltage increases, the individual LED chains are connected with ordinal numbers N going up, and as the supply voltage decreases these are disconnected with ordinal numbers going down, a controlled resistive circuit being associated with said overall supply voltage connection and being configured such that up to a first limit current and/or from a second limit current, an ohmic resistor is connected in order for the input current of the lights to be more sinusoidal.

Description

Circuit for network-compliant operation of light-emitting diodes as well as illuminant and luminaire

[01] The invention relates to a circuit for operating light-emitting diodes in accordance with the network, wherein the circuit has n LED chains with a respective ordinal number N, where n is an integer and greater than 1 and N is an integer and greater than 0, a total supply voltage terminal at which a time-dependent supply voltage, in particular rectified

AC voltage, can be applied, and has an LED chain circuit and the LED chain circuit is set up such that the individual LED chains connected with increasing supply voltage with increasing atomic number N and switched off with decreasing supply voltage with decreasing atomic number, and a light source and a light.

[02] Especially with LED lights with more than 25W, there are problems with generated harmonics of the LED lights, as these deform the sinusoidal mains voltage. This is due in particular to the fact that with increasing mains voltage stepwise corresponding LED chains are switched on. This leads to a staircase-shaped current profile (see FIG. 2, curve with reference number 205), which corresponds only extremely roughly to a desired sinusoidal course.

[03] In particular network operators have to react to such consumers. This requires transformers and Generators are designed to be larger, which in turn increases the cost and reduces the maturity of previous devices, as these must be replaced by newer and better for such consumers (LED lights) designed devices.

[04] The object of the invention is to improve the state of the art.

[05] The object is achieved by a circuit for operation of light-emitting diodes in accordance with the network, the circuit having n LED strings with a respective ordinal number N, where n is an integer and greater than 1 and N is an integer greater than 0, a total supply voltage terminal, on which a time-dependent supply ^¬ voltage, in particular rectified AC voltage, can be applied, and has an LED chain circuit and the LED chain circuit is set up such that the individual LED chains connected with increasing supply voltage with increasing atomic number N and with decreasing Supply voltage with falling atomic number are switched off, wherein the total supply voltage terminal is associated with a controlled resistance circuit (111) which is set up such that up to a first limiting current (211) and / or from a second limiting current (213) an ohmic resistive component (113 ) is connected.

[06] Thus, the current and thus the voltage curve of the circuit can be further adapted to the line voltage profile. In particular, at phase angles of 0 ° to 25 ° and 155 ° to 180 ° in a sinusoidal half-wave can by the connected resistor, a voltage can be tapped, which leads to a consumption current of the circuit in this area, which follows the mains voltage quasi. By selecting the ohmic resistance other consumption profiles can be realized.

[07] As a result, the mains voltage is less burdened by harmonics of the circuit and the mains voltage has a permissible sinusoidal characteristic. Also, corresponding generators and transformers network operators can be designed more compact and cost-effective.

[08] The following conceptual is explained.

[09] The "circuit" is in particular an electronic circuit which is designed on a corresponding board with corresponding components, but also free-wired lines and components can implement the circuit.

In particular, the circuit is designed so that the circuit acts as an ohmic resistance during a complete darkness of all the LEDs. [10] In particular, the circuit is designed such that during a complete darkness of all LEDs the circuit acts as an ohmic resistance ] "Light Emitting Diodes", abbreviated to LED (light emitting diode) in the following, are in particular

Semiconductor devices to understand which at a applied voltage or in a flowing stream of light, in particular in the optical spectrum of 400-800nm, send out.

[12] The "LED chains" generally comprise several light-emitting diodes.If previously LED chains with multiple light-emitting diodes are used, individual diodes, which are controlled accordingly, are referred to as an LED chain, for example one of the LED chains be formed by one or more Zener diodes (zener diodes).

[13] In particular, the "n" indicates the number of LED strings, and usually between 2 and 10 LED strings, and more preferably between 4 and 6 LED strings are used, and the ordinal number "N" numbers the individual strings. Thus, each individual LED chain with indication of the ordinal number N can be uniquely determined.

[14] The "total supply voltage connection" is formed in particular by a connecting line which supplies both the individual LED chain and the controlled resistance circuit (direct or indirect)

Total voltage supply terminal a rectified AC voltage with 230V _eff impressed. This means that generally rectified sinusoidal half-waves with voltage values between 0 and approx. 325V are applied to the total supply voltage connection. [15] The term "time-dependent supply voltage" is understood to mean, in particular, voltages in which the voltage value changes as a function of time or according to a phase angle. <br/><br/> [0008] Due to the fact that this is rectified, especially with an alternating voltage, a time-dependent direct voltage is then present in particular.

[16] By means of the "LED chain wiring", one or more LED strings can be connected in particular depending on the voltage applied to the total supply connection, for example the LED string with the atomic number N = 1 at a rising voltage up to The LED chain with the ordinal number N = 2 can then be connected up to a voltage of 218 V. Up to a voltage of 257 V, the LED chain with the ordinal number N = 3 and up to a voltage of 283V the LED chain with the ordinal number N = 4 and from 320V the LED chain with the ordinal number N = 5 are connected.

[17] When the voltage drops, the individual LED chains are switched off again in reverse order, so that the LED chain with the ordinal number N = 5, from 283V the LED chain with the ordinal number 4 and so on is switched off from a voltage of 320V become. It is particularly advantageous if the LED chain wiring realizes Beschälten the individual LED chains by means of switchable power sources. In particular, these switchable current sources are set up in such a way that a LED Chain tension (voltage drop on the LED chain or on the LED chains) during operation keeps the LED chain or the LED chains substantially constant. This increases the life of the individual LEDs. [18] The "controlled resistance circuit" is in particular a circuit or a circuit part, which is operated in particular up to a "first limiting current", so that a voltage at the ohmic resistance drops and a current flows through it. In a rectified mains voltage half-wave, for example, the resistance circuit between a phase angle φ of 0 ° to about 25 ° connected as ohm 'shear resistance. The first limit current is, in particular, the current value which flows when the first LED chain (N = 1) is operated and thus the LEDs of the first LED chain (N = 1) light up.

[19] In addition, the controlled resistance circuit is a circuit or a circuit part which is operated from a "second limit current" so that a voltage across the ohmic resistance drops and a current flows through it

Resistor circuit connected between a phase angle φ of about 155 ° to 180 ° as ohm 'shear resistance. The value of the first limit current and the second limit current may be identical or different.

[20] In one embodiment, the ohmic resistance device is an ohmic resistance or a Transistor, in particular bipolar transistor, which is operated in particular in a gain range, is.

[21] Thus, alternative ohmic consumers can be provided.

In particular [22] The "ohm ^λ see resistive component" in the present case in particular an electric resistance whose value is substantially independent of the voltage, the current strength and frequency. The behavior of such ohm 'see resistance describes the Ohm's law.

[23] In order to implement the controlled resistance circuit with only one component, the transistor can realize both the control of the resistance circuit and the ohmic resistance.

[24] In another embodiment, the LED chain wiring controls the resistance circuit. Thus, additional control or regulating components such as microprocessors can be avoided, which could in principle implement the control means of the associated computer. Also, FPGAs can be saved or can be used.

In order to operate the circuit, the circuit may have an applied voltage supply which impresses the time-dependent supply voltage of the circuit. [26] In a further aspect, the object is achieved by a luminous means which has a circuit according to one of the preceding claims.

[27] For example, such a lamp can replace the shape and function of a light bulb or a fluorescent tube.

[28] Furthermore, the object can be achieved by a lamp, in particular street lighting system, indoor lighting system, parking garage lighting system or lighting systems for corridors, hotels, aircraft and ships, which has a previously described light source.

[29] In the following, the invention will be explained with reference to exemplary embodiments. 1 shows a schematic representation of a circuit according to the invention with 5 LED chains and an equivalent circuit diagram of a controlled resistance circuit and

FIG. 2 shows a voltage / current profile of a

Half-period from 0 ° to 180 ° for the individual voltages and currents of the circuit of Figure 1.

[30] An LED circuit 101 comprises a Graetz bridge circuit 103 at the output of which a supply line 107 is arranged. The

Supply line 107 conducts a voltage or sets a potential relative to the ground so that the LED chains 121, 123, 125, 127, 129 can be switched and supplied. Furthermore, a controlled resistance circuit 111 is arranged on the supply line 107, which is shown as an equivalent circuit diagram.

[31] At the Graetz bridge rectifier 103, the supply voltage 105 is present as an AC voltage with 230V _eff . The controlled resistance circuit 111 comprises an ohmic resistance 113, which can be electrically switched to ground via a switch 115.

[32] The first LED chain with the ordinal number N = 1 has 44 LEDs, the second LED chain 123 with the ordinal number N = 2 has 24 LEDs, the third LED chain 125 with the ordinal number N = 3 has 12 LEDs, the fourth LED chain 127 with the ordinal number N = 4 has 8 LEDs and the fifth LED chain 129 with the ordinal number N = 5 has a Zener diode.

[33] The first LED chain 121 is the switchable current source 131, the second LED chain 123, the switchable current source 133, the third LED chain 125, the switchable current source 137, the fourth LED chain 127, the switchable current source 139 and the Z Diode 129 associated with the current source 141. Depending on the height of a voltage applied to the supply line 107 with respect to the ground, the individual switchable current sources 131, 133, 137, 139 are switched. Alternatively, the individual switchable current sources 131, 133, 137, 139 are switched depending on the phase angle. This circuit is for example with a Module CL8800 (Sequential Linear LED Driver) from Supertex® Inc. realized.

[34] Hereinafter, the LED circuit 101 without the function of the controlled resistance circuit 111 will be explained in its operation. This operation corresponds to the operation of the LEDs according to the prior art.

[35] The AC line voltage 105 is applied to the Graetz bridge rectifier 103 in the amount of 230V _e ff. As a result, a DC voltage is formed at the output of the Graetz bridge rectifier 103 and thus on the supply line 107. The first (partly sinusoidal) half-wave of this

DC voltage is shown in Figure 2 in a diagram and marked as supply voltage curve 203. In the present case, initially (phase angle = 0 °), all switchable current sources 131, 133, 137, 139 are connected to ground. With increasing voltage and increasing phase angle first the switchable current source 131, then the switchable current source 133, then the switchable current source 137 and finally the switchable current source 139 is turned off, so that at the phase angle of 90 ° only the current source 141 is switched to ground.

[37] Now, with further increasing phase angle and decreasing voltage, the individual switchable current sources 131, 133, 137, 139 are switched to ground in the reverse order. This leads to successively the LED chains 121, 123, 125, 127, 129 on and off.

Alternatively, in the case of the supply voltage forming on the supply line 107 up to a voltage of 142 V, the switchable current source 131 is connected to ground as the only switchable current source. From a voltage of 125V on the supply line 107, the light-emitting diodes of the first LED chain 121 with the ordinal number N = l begin to emit a light. In addition, the switchable current source 131 generates a current which keeps the voltage at the first LED chain 121 constant. As the supply voltage continues to increase, the switchable current source 131 is interrupted and the switchable current source 133 is switched through as the only switchable current source, so that a sufficient voltage is applied both to the first LED chain 121 and to the second LED chain 123 and, in addition, the second LED Chain 123 is lit up. Again, the switchable current source 133 generates a current such that the voltage across the first LED string 121 and the second LED string 123 is constant. This is continued accordingly with further increasing supply voltage for the further LED chains, so that in each case only one of the switchable current sources 131, 133, 135, 137, 139, 141 is connected to ground in succession and the corresponding LED chains are connected.

[39] As soon as the supply voltage reaches the peak value or corresponding peak value at approx. 325V (approx. At 90 °), the voltage values drop accordingly. This results in that the switchable current source 141 interrupted and the fourth switchable current source 139 is turned on and then interrupted again with further falling voltage again and the third switchable current source 137 is turned on. This takes place until the switchable current source 131 is turned on again at the end.

[40] The currents flowing through the LED are also shown in the diagram of FIG. 2 and designated by the reference numeral 205. The step shape of the current profile 205 is achieved in particular by the design of the switchable current sources 131, 133, 135, 137, 139, 141.

[41] The function of the controlled resistance circuit 111 will be explained in more detail below. [42] Through the controlled resistance circuit 111, during the dark phases (cp = 0 ° -25 ° and 155 °-180 °), the switch 115 is switched by the module CL8800 or alternatively by another processor. In a first alternative, the resistor 113 (R1) is designed in such a way that the voltage drop substantially follows the supply voltage profile or a current increase 211 takes place. Depending on the choice of resistance (R2), other current gains 213 can be realized.

[43] In a first implementation 118, an ohmic resistor 119 is connected to ground via a FET 120. Depending on the voltage impressing the CL8800 to the gate of the FET 120, the FET 120 is turned on. The wiring of the FET 120 is configured such that the FET 120 is turned on only during the dark phases.

[44] In a second implementation 116, a bipolar transistor 117 is used whose base is connected by means of the module CL8800 and a resistor (not shown) by means of a current. The bipolar transistor 117 is operated during the dark phases in the gain region, in which the

Bipolartransistor 117 acts quasi ohm 'shear resistance. The wiring of the bipolar transistor 117 is in turn designed such that the bipolar transistor 117 is driven only during the dark phases and during the brightness phases (at least one LED chain lights) blocks.

Reference sign list

101 LED circuit

103 Graetz bridge rectifier

105 alternating voltage

107 supply line

111 equivalent circuit of the resistance circuit

113 ohms resistance

115 switch

116 second real implementation

117 bipolar transistor

118 first real implementation

119 ohms resistance

120 FET

121 first LED chain

123 second LED chain

125 third LED chain

127 fourth LED chain

129 Zener diode

131 first switchable current source 133 second switchable power source

137 third switchable power source

139 fourth switchable power source

141 power source

201 voltage / current phase diagram

203 Supply voltage curve

205 LED chain current profile

207 switch-off time

209 connection time

211 Current profile Rl

213 Current flow R2

Claims

Claims:

1. circuit (101) for network-compatible operation of light-emitting diodes, wherein the circuit n LED chains (121, 123, 125, 127, 129) having a respective atomic number N, wherein the n integer and greater than 1 and the N is integer and greater 0 is, a total supply voltage terminal (107) to which a time-dependent supply voltage (105), in particular rectified AC voltage, can be applied, and an LED chain circuit and the LED chain circuit is arranged such that the individual LED chains with rising supply voltage with increasing atomic number N connected and switched off with decreasing supply voltage with decreasing atomic number, characterized in that the total supply voltage terminal is associated with a controlled resistance circuit (111) which is set up so that up to a first limiting current (211) and / or a second limiting current (213) is connected to an ohmic resistance component (113).

2. A circuit according to claim 1, characterized in that the ohm 'see resistance component ohm' shear resistor (119) or a transistor (117), in particular bipolar transistor, which in particular in a

Reinforcement range is operated.

3. A circuit according to claim 2, characterized in that the transistor realizes the control of the resistor circuit.

4. Circuit according to one of the preceding claims, characterized in that the LED chain circuit controls the resistance circuit.

5. A circuit according to one of the preceding claims characterized by an applied voltage supply (105) which imposes the time-dependent supply voltage of the circuit.

6. Lamp having a circuit according to one of the preceding claims.

7. Light, in particular street lighting system, indoor lighting system, parking garage lighting or lighting systems for corridors, hotels, aircraft and ships, which has a light source according to claim 9.