WO2011101398A2 - Led-spannungsmessung - Google Patents
Led-spannungsmessung Download PDFInfo
- Publication number
- WO2011101398A2 WO2011101398A2 PCT/EP2011/052329 EP2011052329W WO2011101398A2 WO 2011101398 A2 WO2011101398 A2 WO 2011101398A2 EP 2011052329 W EP2011052329 W EP 2011052329W WO 2011101398 A2 WO2011101398 A2 WO 2011101398A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- voltage
- emitting diode
- light
- led
- current mirror
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
- H05B45/59—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits for reducing or suppressing flicker or glow effects
Definitions
- the present invention relates to a voltage measuring circuit for one or more light-emitting diodes (LEDs) and to operating circuits for LEDs with such a circuit for measuring the voltage over an LED path which has one or more LEDs.
- the LEDs can u.a. be organic or inorganic LEDs. It is basically known to use an operating circuit with switching regulators, in particular buck converters, buck converters, boost converters, flyback converters, etc. for driving LEDs (these switching regulators can all also be used in the context of the present invention).
- a control unit controls a clocked semiconductor power switch, by means of which in the on state an inductance is magnetized, wherein the inductance in the off state of the switch then eg. Via the LED discharges or demagnetizes.
- the current does not necessarily have to flow through the light-emitting diode path during the switch-on and switch-off phase (see, for example, step-up converter).
- DE 102006034371 A1 shows an operating circuit for measuring the voltage across the LED track, as shown in the appended FIG.
- an inductance LI is selectively charged and discharged, which forms a freewheeling path with a diode D1 and the LED path L.
- a filter / smoothing capacitor Cl is connected.
- Bus voltage V in ie, a DC supply voltage
- the LED cathode voltage V kath measured.
- a control unit (not shown in FIG. 5) determines, from the difference between the two values, the voltage U LE D across the LED path L, which has one or more LEDs connected in series.
- the measurement of the bus voltage V in takes place in this prior art via a Meßlgriff Ml at the midpoint of a two resistors RIO, RH voltage divider ST1, which is connected in parallel to a supply voltage source VQ.
- the measurement of the LED cathode voltage V kath takes place at a measuring tap M2 at the midpoint of a voltage divider ST2 having two resistors R20, R21, which is connected in series with the LED path L on the cathode side.
- a power loss occurs at each voltage measuring tap M1, M2, that is to say at both voltage dividers ST1, ST2.
- Such power dissipation may be, for example, up to several 100mW per LED channel, i. per LED track, with LED lighting means having more of these channels.
- the cathode-side potential is pulled to zero because of the fact that the filter capacitor C1 is charged via the voltage divider ST2, while an arbitrarily high supply voltage (for example, 400 volts) is applied to the anode side ) may be present.
- an arbitrarily high supply voltage for example, 400 volts
- the invention is therefore based on the object to provide a voltage measuring circuit, in which at least one of the above-mentioned problems is rudimentary reduced.
- the invention deals with a voltage measuring circuit for a light-emitting diode path with at least one light-emitting diode.
- a DC voltage is supplied to the light-emitting diode path.
- Parallel to the light-emitting diode path the primary side of a current mirror is connected.
- On the secondary side of the current mirror is now according to the invention at a measuring resistor to a Voltage drop across the LED strip proportional measuring voltage tapped.
- the current mirror has at least two transistors. Of these, preferably one each connected to the primary and one on the secondary side of the current mirror. To improve the behavior of the current mirror but also circuits come with a larger number of transistors in question.
- the transistors may be bipolar transistors and / or field-effect transistors.
- the at least two transistors can also have identical electrical properties. They can be designed as an integrated component.
- the measuring resistor on the secondary side of the current mirror is connected in a preferred embodiment in series with the secondary-side transistor.
- Another resistor on the primary side of the current mirror is preferably connected in series with the primary-side transistor. This serves to dimension the current to be mirrored.
- the invention deals with an operating circuit for at least a light-emitting diode path with at least one light-emitting diode.
- This operating circuit has a switching regulator circuit.
- the switching regulator circuit is supplied with a DC voltage.
- the switching regulator circuit provides a constant current for the at least one light emitting diode path.
- Parallel to the light-emitting diode path the primary side of a current mirror is connected. On the secondary side is at a resistor a tapped to the voltage drop across the LED strip proportional measurement voltage.
- the operating circuit may have a voltage measuring circuit according to the invention, as has been described above.
- the current flowing through the light-emitting diode path is preferably set by means of a coil and the timing of a switch controlled by a control and / or regulating circuit.
- the measuring voltage can be compared as a feedback signal with a setpoint to clock depending on a possible difference as a control variable the switch. It serves as a monitor, for example as an error detection or shutdown (e.g., short circuit detection, overload detection, etc.). All evaluation functions, i. Control and fault monitoring and possibly shutdown) can be integrated in the example. As IC running control / regulating device.
- the control and / or regulating circuit can determine the time duration between a switch-off and a subsequent switch-on of the switch as a function of the voltage across the at least one light-emitting diode and a time-constant characteristic variable of the coil.
- the control and / or regulating circuit can also detect the coil characteristic via the rising slope of the coil current and by including the coil voltage. In addition, in a preferred embodiment, the control and / or regulating circuit does not detect the current through the at least one light-emitting diode.
- the control and / or regulating circuit may be an integrated circuit.
- the control and / or regulating circuit can control the switch in the form of PWM-modulated signals.
- the switching regulator may be, for example, a boost converter, a buck converter, a flyback converter, etc.
- a capacitor is preferably connected, in particular for smoothing the DC voltage.
- the invention also relates to an LED module, comprising at least one LED, which is supplied by the operating circuit.
- the invention also relates to a lighting device, comprising an LED module with at least one LED, which is supplied by the operating circuit.
- the invention also relates to a method for measuring voltage for a light-emitting diode path with at least one light emitting diode, the LED is supplied with a DC voltage, and parallel to the light emitting diode path, the primary side of a current mirror is connected, wherein on the secondary side of the current mirror to a measuring resistor to a voltage drop across the LED strip proportional measuring voltage is tapped.
- Fig.l shows a first embodiment of
- Fig. 3 shows a third embodiment of
- Fig. 4 shows a fourth embodiment of
- Fig. 5 shows an LED voltage measuring circuit as they are
- FIGS. 1 to 4 show embodiments of the LED voltage measuring circuit 1 according to the invention.
- the LED voltage measuring circuit 1 is designed in such a way that no measuring resistor (R20, R21) in series with the LED path L is required.
- a measurement signal Ü M ESS reproducing the LED voltage Ü LED is coupled out by means of a current mirror S.
- FIGS. 2 to 4 show examples of possible embodiments of the current mirror S, wherein, however, any further configurations of current mirrors, for example with an even higher number of transistors, can be used.
- the current mirror is formed with three transistors Tl, T2, T3, of which two T2, T3 are arranged on the secondary side P2 of the current mirror, wherein the transistors Tl, T2, T3 are formed as bipolar transistors.
- the current mirror S is constructed with a transistor Tl on the primary side PI and a transistor T2 on the secondary side P2, wherein the transistors Tl, T2 are formed as bipolar transistors.
- the current mirror S is constructed with a transistor T1 on the primary side PI and a transistor T2 on the secondary side P2, wherein the transistors T1, T2 are designed as MOSFETs.
- a current mirror S can also be constructed with three MOSFETs.
- the LED voltage measuring circuit 1 according to the invention is used in an operating circuit 2 which is designed to operate a light-emitting diode path L.
- the voltage measuring circuit according to the invention is not limited to the operating circuit 2, but rather can be used in any circuit in which a voltage measurement is to be made. In this respect, the invention is not limited to the field of LEDs, but can be used in a circuit with any load.
- the operating circuit 2 is supplied with an input DC voltage Vin or a rectified AC voltage.
- a switching regulator circuit SRS has a series connection between a semiconductor power switch Sl
- a control and / or regulating circuit SR is provided which prescribes the timing of the switch S1, for example in the form of PW-modulated signals, as the manipulated variable for regulating the light-emitting diode power.
- the feedback signal to which is controlled and which, for example, is compared with a target value
- at least the current flowing through the LED line L is measured. This LED current can be measured at any point in the LED current path.
- the voltage across the LED track is measured by means of the current mirror circuit described.
- the light-emitting diode path has one or more parallel, but preferably in series LEDs and / or OLEDs. These may be, for example, monochromatic LEDs, color-converted white LEDs and / or RGB-LED modules. In the case of the latter, it is particularly advantageous if each luminous color is arranged in a separate LED segment ("LED channel") and each LED segment is regulated via its own feedback signal, such as the current flowing in the LED segment.
- LED channel Parallel to the light-emitting diode path, the primary side PI of a current mirror S is connected.
- the current mirror can have on the primary side as well as on the secondary side in each case a transistor Tl, T2 and a resistor Rl, R2 connected in series therewith.
- the current mirror can also be any other embodiment known from the prior art.
- FETs field-effect transistors
- the current mirror can also be any other embodiment known from the prior art.
- the actual measurement of the LED voltage takes place through the secondary side P2 of the current mirror S. Due to the current mirror function, the identical current flows on the secondary side as on the primary side of the current mirror S and thus through a secondary-side measuring resistor R2.
- the voltage ümess on this resistor R2 is thus the LED voltage üled again.
- the resistor Rl on the primary side PI serves to dimension the measuring voltage Umess picked up at the resistor R2.
- the measured voltage ümess is thus proportional to the voltage Uled, wherein the factor between the two voltages by the size of the resistors Rl and R2 can be adjusted.
- the measurement of the LED voltage for fault monitoring such as e.g. Short circuit detection or overload detection can be used on the LED track or in the output circuit or the wiring.
- the measurement of the LED voltage can be used for the determination of the LED current or the LED temperature, so it can be done an indirect detection of the LED current or the LED temperature. It can be concluded by means of value tables or stored characteristics or formulas with the help of the measured LED voltage on the LED current or the LED temperature.
- the light-emitting diode path L is no longer connected to ground via a measuring circuit on the cathode side, the problem of unwanted glaring of the LEDs is also reduced.
- Another advantage is that when the LED is removed from the circuit, the voltage across the capacitor C1 is discharged through the resistor Rl on the primary side PI of the current mirror. When the LED is then reinserted, the voltage of the charged capacitor C1 does not immediately drop, but rather a voltage is applied across the LED only when it is switched on again.
- the problem is that when re-inserting the cathode-side potential is pulled to zero due to the measuring channel, while the anode side, the supply voltage of, for example, 400 volts applied, thus resolved.
- a so-called 'hot-swapping' which corresponds to the removal and re-insertion of an LED during operation, there is the risk that the LED will be destroyed becomes significantly smaller than in the prior art.
- the 'hot-swapping ' * is electrically equivalent to an interrupt error, ie the LED link is interrupted and then the supply voltage is applied again.
- the voltage measuring circuit counteracts this risk during 'hot-swapping', since the voltage across the capacitor C1 is discharged through the resistor Rl on the primary side PI of the current mirror.
- the two transistors Tl and T2 of the current mirror should have identical electrical properties, the two transistors are preferably integrated in one component.
- a method for measuring voltage for a light-emitting diode path L with at least one light-emitting diode LED is possible, wherein the light-emitting diode is supplied with a DC voltage.
- the primary side PI of a current mirror S is connected.
- a measuring voltage UMESS proportional to the voltage drop ULED across the light-emitting diode path L is picked off at a measuring resistor R2.
- the current mirror measurement can be used to measure a DC current in a measuring branch P2 which is not connected in series with the light-emitting diode path. There is also no difference measurement (bus voltage minus cathode voltage) instead, but a direct measurement of the voltage across the LED track.
- a measurement of the light-emitting diode path voltage is performed by means of a measuring resistor, which is not connected in series with the light-emitting diode path. But it is also no measurement of the LED current by means of a measuring resistor, which is connected in series with the light-emitting diode path, necessary by the voltage measuring circuit according to the invention.
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112011100594.6T DE112011100594B4 (de) | 2010-02-18 | 2011-02-17 | LED-Spannungsmessung |
EP11703901.6A EP2540139B1 (de) | 2010-02-18 | 2011-02-17 | Led-spannungsmessung |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102010002081A DE102010002081A1 (de) | 2010-02-18 | 2010-02-18 | LED-Spannungsmessung |
DE102010002081.8 | 2010-02-18 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2011101398A2 true WO2011101398A2 (de) | 2011-08-25 |
WO2011101398A3 WO2011101398A3 (de) | 2014-03-13 |
Family
ID=44044112
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2011/052329 WO2011101398A2 (de) | 2010-02-18 | 2011-02-17 | Led-spannungsmessung |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2540139B1 (de) |
DE (2) | DE102010002081A1 (de) |
WO (1) | WO2011101398A2 (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT13688U1 (de) * | 2012-12-06 | 2014-06-15 | Tridonic Gmbh & Co Kg | Betriebsgerät für Leuchtmittel |
WO2014085837A3 (de) * | 2012-12-06 | 2014-09-04 | Tridonic Gmbh & Co Kg | Betriebsgerät für leuchtmittel |
CN113193910A (zh) * | 2021-04-12 | 2021-07-30 | 武汉船舶通信研究所(中国船舶重工集团公司第七二二研究所) | 一种led电光调制频率特性的自动测量装置 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102011116231B4 (de) | 2011-10-17 | 2017-12-21 | Austriamicrosystems Ag | Beleuchtungsanordnung und Verfahren zum Erkennen eines Kurzschlusses bei Dioden |
DE102012220761A1 (de) * | 2012-11-14 | 2014-05-15 | Bag Engineering Gmbh | Multifunktionales Betriebsgerät zum Versorgen eines Verbrauchers wie einer LED-Einrichtung |
DE102020208944A1 (de) | 2020-07-16 | 2022-01-20 | Osram Gmbh | Verfahren und schaltungsanordnung zur detektion eines teilausfalls eines leuchtmittels mit mindestens einem strang von halbleiterlichtquellen |
DE102020132666B3 (de) | 2020-12-08 | 2022-03-10 | Elmos Semiconductor Se | Vorrichtung und Verfahren zur sicherheitsrelevanten Erfassung des Spannungsabfalls über ein Leuchtmittel in einem Fahrzeug |
DE102020008118A1 (de) | 2020-12-08 | 2022-06-09 | Elmos Semiconductor Se | Verfahren zur sicherheitsrelevanten Erfassung des Spannungsabfalls über ein Leuchtmittel in einem Fahrzeug |
Citations (1)
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DE102006034371A1 (de) | 2006-04-21 | 2007-10-25 | Tridonicatco Schweiz Ag | Betriebsschaltung für Leuchtdioden |
Family Cites Families (11)
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JP2991893B2 (ja) * | 1993-05-31 | 1999-12-20 | 富士通株式会社 | 発光素子の駆動回路及びこれを用いた光増幅中継器 |
JPH0792205A (ja) * | 1993-09-27 | 1995-04-07 | Matsushita Electric Works Ltd | 電源電圧検知装置 |
JP3417891B2 (ja) * | 1999-10-27 | 2003-06-16 | 株式会社オートネットワーク技術研究所 | 電流検出装置 |
DE10140331C2 (de) * | 2001-08-16 | 2003-11-06 | Siemens Ag | Lichtzeichen zur Verkehrssteuerung und Verfahren zur Funktionsüberwachung eines solchen Zeichens |
DE102004027676B4 (de) * | 2004-04-30 | 2006-06-14 | Siemens Ag | Verfahren und Vorrichtung zum Prüfen wenigstens eines LED-Strangs |
US7884557B2 (en) * | 2006-07-14 | 2011-02-08 | Wolfson Microelectronics Plc | Protection circuit and method |
AT504949B1 (de) * | 2007-02-20 | 2008-11-15 | Zizala Lichtsysteme Gmbh | Schaltungsanordnung zur erkennung eines kurzschlusses von leuchtdioden |
DE202007007777U1 (de) * | 2007-06-01 | 2007-08-16 | Conwys Ag | Schaltungsanordnung |
DE202007007776U1 (de) * | 2007-06-01 | 2007-08-09 | Conwys Ag | Anhängeranschlußgerät |
US8421375B2 (en) * | 2007-06-25 | 2013-04-16 | Ingersoll-Rand Company | Amplification circuit and heat sink used with a light emitting apparatus having varying voltages |
JP4994253B2 (ja) * | 2008-01-24 | 2012-08-08 | 株式会社ジャパンディスプレイイースト | 液晶表示装置 |
-
2010
- 2010-02-18 DE DE102010002081A patent/DE102010002081A1/de not_active Withdrawn
-
2011
- 2011-02-17 WO PCT/EP2011/052329 patent/WO2011101398A2/de active Application Filing
- 2011-02-17 DE DE112011100594.6T patent/DE112011100594B4/de active Active
- 2011-02-17 EP EP11703901.6A patent/EP2540139B1/de active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102006034371A1 (de) | 2006-04-21 | 2007-10-25 | Tridonicatco Schweiz Ag | Betriebsschaltung für Leuchtdioden |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT13688U1 (de) * | 2012-12-06 | 2014-06-15 | Tridonic Gmbh & Co Kg | Betriebsgerät für Leuchtmittel |
WO2014085837A3 (de) * | 2012-12-06 | 2014-09-04 | Tridonic Gmbh & Co Kg | Betriebsgerät für leuchtmittel |
CN104838725A (zh) * | 2012-12-06 | 2015-08-12 | 赤多尼科两合股份有限公司 | 用于发光机构的操作装置 |
CN113193910A (zh) * | 2021-04-12 | 2021-07-30 | 武汉船舶通信研究所(中国船舶重工集团公司第七二二研究所) | 一种led电光调制频率特性的自动测量装置 |
Also Published As
Publication number | Publication date |
---|---|
DE112011100594B4 (de) | 2015-09-03 |
DE112011100594A5 (de) | 2013-01-24 |
EP2540139A2 (de) | 2013-01-02 |
DE102010002081A1 (de) | 2011-08-18 |
WO2011101398A3 (de) | 2014-03-13 |
EP2540139B1 (de) | 2016-10-05 |
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