DE102012209779A1 - Circuit for controlling semiconductor light emitting elements e.g. LEDs, of lamp, has electronic switches controlled by microcontroller, and semiconductor luminous elements switched in series in different combinations by switches - Google Patents

Abstract

The circuit has multiple electronic switches (S12-S33) controlled by a control unit i.e. microcontroller. Multiple semiconductor luminous elements (D1-D4) are switched in series in different combinations by the electronic switches. The semiconductor luminous elements are arranged in parallel with each other. A part of the semiconductor luminous elements is switched as a function of height of a rectified alternating voltage i.e. rectified pulsating net alternating voltage. A current regulator is switched in series to the part of the semiconductor luminous elements. An independent claim is also included for a method for controlling semiconductor light emitting elements.

Description

The invention relates to a circuit and a method for driving a plurality of semiconductor light elements and a lamp with such a circuit.

LEDs can not individually directly to a mains voltage in the amount of z. B. 220 V can be operated without being destroyed. Usually, an electronic circuit with a transformer (electronic ballast) or a transformer is provided, which converts the mains voltage for operation of the LEDs to a suitable supply voltage or a suitable operating current.

It is known to connect several light emitting diodes in series and to operate by means of rectifiers and series resistors via a mains AC voltage. However, such a circuit has the disadvantage that the emitted light has a high ripple in the light current, in particular because the light emitting diodes operate only in a very limited voltage range or emit light.

The object of the invention is to avoid the above-mentioned disadvantages and in particular to provide a solution in order to be able to operate light-emitting diodes as directly and efficiently as possible via a mains voltage.

This object is achieved according to the features of the independent claims. Further developments of the invention will become apparent from the dependent claims.

• – mit mehreren elektronischen Schaltern,
• – wobei die mehreren Halbleiterleuchtelemente in unterschiedlichen Kombinationen mittels der elektronischen Schalter in Reihe schaltbar sind und
• – wobei die mehreren Halbleiterleuchtelemente in unterschiedlichen Kombinationen mittels der elektronischen Schalter parallel zueinander schaltbar sind.

To solve the problem, a circuit for driving a plurality of semiconductor light elements is proposed,

• - with several electronic switches,
• - Wherein the plurality of semiconductor light elements are switchable in different combinations by means of the electronic switches in series, and
• - Wherein the plurality of semiconductor light elements in different combinations by means of the electronic switch can be switched in parallel to each other.

By means of the electronic switch, a switching function is electronically controlled. The electronic switch may comprise a transistor, a MOSFET, an operational amplifier, a comparator or a component which can be acted upon by a switching function.

The semiconductor light elements are, for example, LEDs, LED chips or LED modules. A semiconductor light-emitting element can also comprise at least one OLED (organic light-emitting diode) or a module with at least one OLED. Furthermore, series circuits of the same or different types of semiconductor light elements may be provided.

The plurality of semiconductor light elements may also be clusters of semiconductor light elements, e.g. B. series circuits of semiconductor light elements.

Thus, voltage-dependent, the electronic switch, z. B. by driving a microcontroller, closed and opened. In this way, it can be achieved that the number of series-connected semiconductor light-emitting elements is set as a function of the level of the instantaneously applied voltage. In addition to the number of series-connected semiconductor light-emitting elements, the remaining semiconductor light-emitting elements or at least part of these semiconductor light-emitting elements can be connected in parallel with the series-connected semiconductor light-emitting elements.

It is an advantage that the semiconductor light elements can be operated by means of a mains voltage, without requiring an electronic control gear, z. B. in the form of a switching power supply is needed. This saves space, weight and improves the life of the circuit, because z. B. no electrolytic capacitors are needed. Also, no throttles, transformers or transformers are necessary for the inventive solution.

Another advantage is to achieve a constant (or almost constant) performance of the at least one semiconductor element. In this case, an averaging can take place over time and / or via one (or more) half-waves of the mains alternating voltage. Preferably, no energy storage is necessary or - if an energy storage is to be used - the energy storage can be dimensioned correspondingly small.

A further development is that the electronic switches can be controlled by a control unit, comprising in particular a microcontroller.

Another development is that a first part of the semiconductor light-emitting elements is connected in series as a function of the level of a rectified AC voltage, in particular as a function of the level of a rectified pulsating AC line voltage.

In this case, it is advantageous that, depending on the height of the pulsed rectified mains alternating voltage, the number of series-connected semiconductor light-emitting elements can be determined such that z. B. drops approximately the instantaneous voltage at these semiconductor light elements. Accordingly, the shape of the pulsed rectified AC line voltage can be followed by the voltage drop across the series connected semiconductor light elements. In this case, in particular, a part of the rectified mains alternating voltage can also drop at a linear regulator.

In particular, it is a development that the height of the rectified AC voltage can be determined and is used in sections for driving the first part of the semiconductor light elements.

In particular, the control unit can determine the level of the currently applied rectified AC voltage and correspondingly connect the semiconductor light elements in series so that the voltage drop across these semiconductor light elements is less than or equal to the rectified AC voltage (ie, if possible, but not exceeded). This can be done continuously or at predetermined times. It is also possible to use intervals or sections for the voltage values of the rectified alternating voltage in order to connect the semiconductor light-emitting elements in series and / or in parallel. The excess voltage can z. B. fall on a switchable resistive element (eg., A resistor).

It is also a development that a second part of the semiconductor light-emitting elements is connected in parallel with the first part of the semiconductor light-emitting elements.

Furthermore, it is a further development that a current regulator is connected in series with the first part of the semiconductor light-emitting elements.

The current regulator may have at least one resistive element or a linear regulator.

In the context of an additional development, the current regulator comprises a series connection of at least one resistor, wherein the at least one resistor can be bridged by means of at least one electronic switch.

A next development is that an electronic switch is connected in parallel to each of the resistors.

An embodiment is that the current regulator is controllable by means of a dimmer.

One option is that the current controller is controlled and thus a brightness control (dimming) of the semiconductor light elements can be achieved. The control can be done in different ways, eg. B. via a potentiometer, a DALI system, a microcontroller or a 1-10 V interface.

• – bei dem die mehreren Halbleiterleuchtelemente in unterschiedlichen Kombinationen mittels elektronischer Schalter in Reihe geschaltet werden und
• – bei dem die mehreren Halbleiterleuchtelemente in unterschiedlichen Kombinationen mittels der elektronischen Schalter parallel zueinander geschaltet werden.

The above object is also achieved by a method for driving a plurality of semiconductor light elements,

• - In which the plurality of semiconductor light elements are connected in different combinations by means of electronic switches in series and
• - In which the plurality of semiconductor light elements are connected in different combinations by means of the electronic switch in parallel.

One embodiment is that a first part of the semiconductor light-emitting elements is connected in series as a function of the level of a rectified AC voltage, in particular as a function of the magnitude of a rectified pulsating AC line voltage.

• – die Höhe der gleichgerichteten Wechselspannung bestimmt wird und
• – der erste Teil der Halbleiterleuchtelemente basierend auf der Höhe der gleichgerichteten Wechselspannung insbesondere abschnittsweise angesteuert wird.

Also it is an embodiment that

• - The height of the rectified AC voltage is determined and
• - The first part of the semiconductor light-emitting elements based on the height of the rectified AC voltage is driven in particular sections.

Another development is that a second part of the semiconductor light-emitting elements is connected in parallel with the first part of the semiconductor light-emitting elements.

An additional development is that a current regulator is connected in series with the first part of the semiconductor light-emitting elements.

Further, the above object is achieved by a lamp having a circuit of the present embodiments.

Embodiments of the invention are illustrated and explained below with reference to the drawings.

Show it:

1 a schematic circuit arrangement for the efficient operation of light emitting diodes to a rectified AC voltage, z. B. an AC mains voltage;

2 an exemplary circuit arrangement in which a plurality of light emitting diodes via electronic switches, which are controlled by a microcontroller, in series and / or parallel to each other are switchable.

1 shows a schematic circuit arrangement for the efficient operation of light emitting diodes at a rectified AC voltage 101 , z. B. an AC mains voltage.

The (mains) AC voltage 101 is via a rectifier 102 converted into a pulsating DC voltage, which is connected to a node 103 (opposite to a ground potential 104 ) is present. By way of example, four light-emitting diodes D1 to D4 are provided, which can be connected in series and / or in parallel via electronic switches.

The knot 103 is via the light emitting diode D1 with a node 105 connected. The knot 105 is via an electronic switch S11 with a node 106 connected. The knot 106 is via the LED D2 with a node 107 connected. The knot 107 is via an electronic switch S21 with a node 108 connected. The knot 108 is via the LED D3 with a node 109 connected. The knot 109 is via an electronic switch S31 with a node 110 connected. The knot 110 is via the LED D4 with a node 111 connected.

The knot 103 is via an electronic switch S12 with the node 106 , via an electronic switch S22 with the node 108 and via an electronic switch S32 with the node 110 connected.

The knot 111 is via an electronic switch S33 with the node 109 , via an electronic switch S23 with the node 107 and via an electronic switch S13 with the node 105 connected.

The knot 111 is further connected via a series circuit of a resistor R1, a resistor R2 and a resistor R3 to the ground potential 104 connected in parallel to the resistor R1, an electronic switch S41, parallel to the resistor R2, an electronic switch S42 and parallel to the resistor R3, an electronic switch S43 is arranged.

The light-emitting diodes D1 to D4 are aligned so that their anode in each case in the direction of the node 103 shows.

The electronic switches are z. B. as transistors or mosfets and can by a microcontroller (not in 1 shown).

Thus, the height of the pulsating DC voltage of the number of series-connected LEDs can be adjusted (by appropriate adjustment of the electronic switch). This allows the use of a large voltage range to emit light by means of the LEDs. Furthermore, in 1 arranged a plurality of electronic switches, so that a parallel connection of the LEDs - can be achieved - depending on the level of the mains voltage. In addition, a resistance value which is switchable and adaptable in series with the light-emitting diodes can also be adjusted depending on the level of the mains voltage. Thus, a nearly constant LED power can be achieved over the duration of the pulsed rectified AC line voltage.

• (1) U103 > 12 V: geschlossen: S11, S21, S31 offen: S12, S22, S32, S13, S23, S33 Es leuchten alle vier in Reihe geschalteten Leuchtdioden.
• (2) 12 V > U103 > 9 V: geschlossen: S12, S21, S31 offen: S11, S13, S22, S23, S32, S33 Es leuchten nur die in Reihe geschalteten Leuchtdioden D2 bis D4, die Leuchtdiode D1 ist nicht aktiv.
• (3) 9 V > U103 > 6 V: geschlossen: S22, S31, S11, S23 offen: S12, S13, S21, S32, S33 Es leuchten alle vier Leuchtdioden, wobei die Leuchtdioden D1 und D2 jetzt parallel zu den Leuchtdioden D3 und D4 geschaltet sind. Entsprechend sind nur jeweils zwei der Leuchtdioden miteinander in Reihe geschaltet.
• (4) 6 V > U103 > 3 V: geschlossen: S12, S22, S32, S13, S23, S33 offen: S11, S21, S31 Es leuchten alle vier Leuchtdioden, wobei die Leuchtdioden D1 bis D4 parallel geschaltet sind.

For example, with regard to 1 Assuming that a light emitting diode is operated with a voltage of 3 V, the voltage for operating the light emitting diodes D1 to D4 is therefore 12 V. By way of example, with regard to 1 the following four cases are distinguished, with the switches S41 to S43 and the resistors R1 to R3 not being taken into account for the sake of simplicity:

• (1) U103> 12 V: closed: S11, S21, S31 open: S12, S22, S32, S13, S23, S33 All four light-emitting diodes connected in series light up.
• (2) 12 V>U103> 9 V: closed: S12, S21, S31 open: S11, S13, S22, S23, S32, S33 Only the light-emitting diodes D2 to D4 connected in series are lit, the LED D1 is not active.
• (3) 9 V>U103> 6 V: closed: S22, S31, S11, S23 open: S12, S13, S21, S32, S33 All four light-emitting diodes light up, the light-emitting diodes D1 and D2 now being parallel to the LEDs D3 and D3 D4 are switched. Accordingly, only two of the LEDs are connected in series with each other.
• (4) 6 V>U103> 3 V: closed: S12, S22, S32, S13, S23, S33 open: S11, S21, S31 All four light-emitting diodes are lit, with light-emitting diodes D1 to D4 connected in parallel.

Here, U103 denotes the voltage at the node 103 ,

It is an advantage that the light emitting diodes can be operated by means of a mains voltage, without requiring an electronic control gear, z. B. in the form of a switching power supply is needed. This saves space, weight and improves the life of the circuit, because z. B. no electrolytic capacitors are needed. Also, no throttles, transformers or transformers are necessary for the inventive solution.

Thus, voltage-dependent, the electronic switch, z. B. by driving a microcontroller, closed and opened. In this way it can be achieved that the number of light-emitting diodes connected in series is set as a function of the level of the instantaneously applied voltage. In addition to the number of light-emitting diodes connected in series, the remaining light-emitting diodes or at least some of these light-emitting diodes may be connected in parallel with the light-emitting diodes connected in series.

Furthermore, it is possible to connect the resistors R1 to R3 via the electronic switches S41 to S43 in series with the light-emitting diodes or to bridge at least one of the resistors R1 to R3. Thus, the voltage drop across the LEDs connected in series and / or the current can be adjusted by the light-emitting diodes connected in series.

It should be noted that instead of the example in 1 shown light-emitting diodes also several series-connected light-emitting diodes or lighting modules with multiple light emitting diodes (in series and / or parallel connection) can be used. The light-emitting diodes may be semiconductor light-emitting elements. The light-emitting diodes can have different dimensions or different properties (eg colors).

With a correspondingly favorable design of the circuit, a high efficiency in the utilization of the mains voltage can be achieved.

2 shows an exemplary circuit arrangement in which a plurality of light-emitting diodes 201 to 204 via electronic switches, by a microcontroller 205 are controlled, in series and / or parallel to each other are switchable.

The (mains) AC voltage 206 is via a rectifier 207 converted into a pulsating DC voltage, which is connected to a node 208 (opposite to a ground potential 209 ) is present.

The knot 208 is via a series connection of a resistor 210 and a resistance 211 connected to the ground potential, both the center tap this series circuit, the ground potential 209 as well as the knot 208 with the microcontroller 205 are connected.

The microcontroller 205 On the output side, the gate connections of n-channel MOSFETs can be routed via one line at a time 212 to 220 control, which are used as electronic switches in the sense of the above statements. The source connections of the mosfets 212 to 220 are at ground potential 209 connected.

The drain connection of the mosfet 212 is with a node 221 connected, which has a resistance 222 with the node 208 connected is. The knot 221 is at the gate terminal of a p-channel mosfet 223 connected. The source connection of the mosfet 223 is with the node 208 connected, the drain connection of the mosfet 223 is with a node 224 connected.

The drain connection of the mosfet 213 is with a node 225 connected, which has a resistance 226 with the node 208 connected is. The knot 225 is at the gate terminal of a p-channel mosfet 227 connected. The source connection of the mosfet 227 is with the node 208 connected, the drain connection of the mosfet 227 is with a node 228 connected.

The drain connection of the mosfet 214 is with a node 229 connected, which has a resistance 230 with the node 208 connected is. The knot 229 is at the gate terminal of a p-channel mosfet 231 connected. The source connection of the mosfet 231 is with the node 208 connected, the drain connection of the mosfet 231 is with a node 232 connected.

The drain connection of the mosfet 215 is with a node 233 connected, which has a resistance 234 with the node 208 connected is. The knot 233 is at the gate terminal of an n-channel mosfet 235 connected. The source connection of the mosfet 235 is with the node 224 connected, the drain connection of the mosfet 235 is over the diode 201 with the node 208 connected.

The drain connection of the mosfet 216 is with a node 236 connected, which has a resistance 237 with the node 224 connected is. The knot 236 is at the gate terminal of an n-channel mosfet 238 connected. The source connection of the mosfet 238 is with the node 228 connected, the drain connection of the mosfet 238 is over the diode 202 with the node 224 connected.

The drain connection of the mosfet 217 is with a node 239 connected, which has a resistance 240 with the node 228 connected is. The knot 239 is at the gate terminal of an n-channel mosfet 241 connected. The source connection of the mosfet 241 is with the node 232 connected, the drain connection of the mosfet 241 is over the diode 203 with the node 228 connected.

The drain connection of the mosfet 218 is with a node 242 connected, which has a resistance 243 with the node 208 connected is. The knot 242 is at the gate terminal of an n-channel mosfet 244 connected. The source connection of the mosfet 244 is with a node 245 connected, the drain connection of the mosfet 244 is with the drain connection of the mosfet 241 connected.

The drain connection of the mosfet 219 is with a node 246 connected, which has a resistance 247 with the node 208 connected is. The knot 246 is at the gate terminal of an n-channel mosfet 248 connected. The source connection of the mosfet 248 is with the node 245 connected, the drain connection of the mosfet 248 is with the drain connection of the mosfet 238 connected.

The drain connection of the mosfet 220 is with a node 249 connected, which has a resistance 250 with the node 208 connected is. The knot 249 is at the gate terminal of an n-channel mosfet 251 connected. The source connection of the mosfet 251 is with the node 245 connected, the drain connection of the mosfet 251 is with the drain connection of the mosfet 235 connected.

The cathodes of the diodes 201 to 204 each point in the direction of the ground potential 209 ,

LIST OF REFERENCE NUMBERS

101

AC voltage (squelle)

102

rectifier

103

node

104

ground potential

105-111

node

D1-D4

led

Sij

electronic switch (i = 1 ... 4, j = 1 ... 3)

R1-R3

resistance

201-204

led

205

microcontroller

206

AC voltage (squelle)

207

rectifier

208

node

209

ground potential

210-211

resistance

212-220

Mosfet (electronic switch)

221

node

222

resistance

223

Mosfet

224

node

225

node

226

resistance

227

Mosfet

228

node

229

node

230

resistance

231

Mosfet

232

node

233

node

234

resistance

235

Mosfet

236

node

237

resistance

238

Mosfet

239

node

240

resistance

241

Mosfet

242

node

243

resistance

244

Mosfet

245

node

246

node

247

resistance

248

Mosfet

249

node

250

resistance

251

Mosfet

Claims (15)

Circuit for driving a plurality of semiconductor light elements (D1-D4) - with several electronic switches (S12-S33), - Wherein the plurality of semiconductor light elements are switchable in different combinations by means of the electronic switches in series, and - Wherein the plurality of semiconductor light elements in different combinations by means of the electronic switch can be switched in parallel to each other. Circuit according to Claim 1, in which the electronic switches are provided by a control unit, in particular a microcontroller ( 205 ), are controllable. Circuit according to one of the preceding claims, in which a first part of the semiconductor light-emitting elements is connected in series as a function of the level of a rectified AC voltage, in particular as a function of the magnitude of a rectified pulsating AC line voltage. A circuit according to claim 3, wherein the height of the rectified AC voltage can be determined and in sections for driving the first part of the semiconductor light elements can be used. A circuit according to any one of claims 3 or 4, wherein a second part of the semiconductor light-emitting elements is connected in parallel with the first part of the semiconductor light-emitting elements. A circuit according to any one of claims 3 to 5, wherein a current regulator is connected in series with the first part of the semiconductor light emitting elements. Circuit according to claim 6, wherein the current regulator comprises a series connection of at least one resistor (R1-R3), wherein the at least one resistor (R1-R3) can be bridged by means of at least one electronic switch. A circuit according to claim 7, wherein an electronic switch (S41-S43) is connected in parallel with each of said resistors. Circuit according to one of claims 6 to 8, wherein the current regulator is controllable by means of a dimming. Method for controlling a plurality of semiconductor light elements, - In which the plurality of semiconductor light elements are connected in different combinations by means of electronic switches in series and - In which the plurality of semiconductor light elements are connected in different combinations by means of the electronic switch in parallel. Method according to Claim 10, in which a first part of the semiconductor light-emitting elements is connected in series as a function of the magnitude of a rectified alternating voltage, in particular as a function of the level of a rectified pulsating mains alternating voltage. Method according to claim 11, - In which the height of the rectified AC voltage is determined and - In which the first part of the semiconductor light-emitting elements based on the height of the rectified AC voltage is driven in particular sections. Method according to one of Claims 11 or 12, in which a second part of the semiconductor light-emitting elements is connected in parallel with the first part of the semiconductor light-emitting elements. A method according to any one of claims 11 to 13, wherein a current regulator is connected in series with the first part of the semiconductor light emitting elements. A lamp comprising a circuit according to one of claims 1 to 9.

Images