EP2992735A1 - Circuit d'exploitation pour diodes électroluminescentes - Google Patents

Circuit d'exploitation pour diodes électroluminescentes

Info

Publication number
EP2992735A1
EP2992735A1 EP14731538.6A EP14731538A EP2992735A1 EP 2992735 A1 EP2992735 A1 EP 2992735A1 EP 14731538 A EP14731538 A EP 14731538A EP 2992735 A1 EP2992735 A1 EP 2992735A1
Authority
EP
European Patent Office
Prior art keywords
switch
condition
current
operating circuit
led
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14731538.6A
Other languages
German (de)
English (en)
Inventor
Frank Lochmann
Markus SCHERTLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tridonic GmbH and Co KG
Original Assignee
Tridonic GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tridonic GmbH and Co KG filed Critical Tridonic GmbH and Co KG
Publication of EP2992735A1 publication Critical patent/EP2992735A1/fr
Withdrawn legal-status Critical Current

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]
    • H05B45/10—Controlling the intensity of the light
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • 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]
    • 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]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/32—Pulse-control circuits
    • H05B45/327—Burst dimming
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • 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]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/12—Controlling the intensity of the light using optical feedback
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • the invention relates to an operating circuit with
  • Semiconductor light sources such as light emitting diodes have become increasingly interesting for lighting applications in recent years. The reason for this is, among other things, that crucial technical
  • Brightness as well as the light efficiency (light output per watt) of these light sources could be achieved.
  • LEDs have become an attractive alternative to conventional light sources such as incandescent or
  • LEDs Semiconductor light sources are well known in the art and will hereafter be referred to as LEDs
  • LEDs are therefore always operated in a mode in which the current flow through the LED is controlled.
  • switching regulator such as step-down converter or buck
  • the time average of the LED current represents the RMS current through the LED arrangement and is a measure of the brightness of the LEDs.
  • the LEDs are supplied by the operating device low-frequency pulse packets (typically with a frequency in the range of 100-1000 Hz) with (in the time average) constant current amplitude.
  • the current within a pulse packet is superimposed on the above-mentioned high-frequency ripple.
  • the brightness of the LEDs can now be controlled by changing the turn-on ratio of the pulse packets; For example, the LEDs may be dimmed down by increasing the time interval between the pulse packets (ie, the power up phase) or the width of the pulses
  • Pulse packets (ie the power-on phase) is reduced.
  • a practical requirement of the operating device is that it can be used as flexibly and versatile as possible, for example, regardless of how many LEDs are actually connected as a load and should be operated.
  • the load may also change during operation if, for example, an LED fails.
  • the LEDs are, for example, in a so-called 'continuous conduction mode' or
  • a buck converter for the operation of at least one LED (or a plurality of LEDs connected in series), which has a first switch S1, is shown as a basic circuit.
  • the operating circuit is supplied with a DC voltage or a rectified AC voltage U0.
  • Operating circuit for at least one LED for operation provide at least one LED, which in a simple way to improve the regulation of the operation of the lamp. This object is achieved by the features of the independent claims.
  • the dependent claims further form the central idea of the invention in a particularly advantageous manner.
  • a supply voltage for at least one LED is by means of a coil and a through a
  • Control unit clocked first switch
  • the control unit turns on the first switch upon reaching a restart condition, and the control unit turns off the first switch upon reaching a turn-off condition.
  • Restart condition and / or the switch-off condition can be set depending on the current dimming level.
  • the reclosing condition may be the expiration of a
  • the reclosing condition can also be a voltage monitored at the operating circuit, preferably the voltage at a secondary winding inductively coupled to the coil.
  • the switch-off condition may be the expiration of a switch-on period.
  • the switch-off condition may be a current monitored by the operating circuit, preferably the current through a measuring resistor (shunt, RS).
  • the control / regulating unit can both the achievement of the switch-off condition as well as the achievement of the
  • first sensor unit which generates a first sensor signal dependent on the current through the first switch
  • second sensor unit which detects the achievement of the demagnetization of the coil or the current flow through the LED during the switch-off phase of the first switch and a sensor signal generated, and that the sensor signals are supplied to the control unit and processed.
  • the first sensor unit which generates a first sensor signal dependent on the current through the first switch
  • a second sensor unit which detects the achievement of the demagnetization of the coil or the current flow through the LED during the switch-off phase of the first switch and a sensor signal generated, and that the sensor signals are supplied to the control unit and processed.
  • the operating circuit provides a supply voltage for at least one LED by means of a coil and a clocked by a control / regulating unit first switch, wherein when the first switch in the coil, an energy is temporarily stored, which is switched off with the first switch via a diode and at least one LED discharges.
  • There is a first sensor unit which generates a current dependent on the current through the first switch first sensor signal, and a second sensor unit, the achievement of the Demagnetization of the coil or the current flow detected by the LED during the turn-off of the first switch and generates a second sensor signal.
  • Sensor signals are supplied to and processed by the control unit, the control unit turning on the first switch at the time when the coil is demagnetized and / or the diode is turned off, the control unit connecting the first switch to the first switch
  • the control unit compares the averaged current detected by the first switch and a reference value, and the control unit adjusts according to
  • the reference value can be set depending on the current dimming level.
  • the averaged current can be detected by a low-pass filter on the measuring resistor, the low-pass filter can be separated during the pulse pause of a low-frequency PWM signal by means of a third switch.
  • a capacitor may be provided that is parallel to the at least one LED and that maintains current through the LED during the demagnetization phase of the coil.
  • Figure la shows a circuit arrangement according to the
  • FIG. 1b shows a diagram with the time profile of the LED current in the circuit arrangement of FIG. 1a (prior art).
  • FIG. 2 a shows a first example of an operating circuit (buck) according to the invention for LEDs
  • FIG. 2b shows a diagram which is time-dependent
  • FIG. 5 shows a modification of the circuit of FIG. 2a (Buck Boost).
  • FIG. 6 shows a further specific embodiment of the invention
  • FIG. 7 shows a further specific embodiment of the invention
  • FIG. 8 shows a diagram that is time-dependent
  • Figure la and Figure lb show the state of the art.
  • the circuit arrangement shown in FIG. 2a is an example of a possible operating circuit. It is used to operate at least one (or more in series and / or parallel switched) LED. For example, in the example shown, two LEDs are in series
  • the LED or the serially and / or parallel-connected LEDs are also referred to below as the LED track.
  • An advantage of the present invention is that the operating circuit adapts very flexibly to the type and number of serially connected LEDs.
  • the circuit is supplied with a DC voltage U0, which of course can also be a rectified AC voltage.
  • the LEDs are connected in series with a coil LI and a first switch Sl.
  • the circuit arrangement has a diode D1 (the diode D1 is connected in parallel with the LEDs and the coil L1) and optionally a capacitor Gl connected in parallel with the LEDs.
  • Capacitor Cl contributes to the flow of current through the LED track.
  • Capacitor Cl this leads to a smoothing of the current through the LEDs.
  • a field effect transistor or bipolar transistor can be used as a first switch Sl.
  • the first switch Sl a field effect transistor or bipolar transistor can be used as a first switch Sl.
  • Switch S1 is switched to high frequency, typically in a frequency range above 10 kHz.
  • a possible embodiment of the circuit is that the first switch Sl is spared in operation, since it can be switched on, as explained later, when the power applied to it is almost zero.
  • Another possible embodiment of the circuit is that for the first switch Sl and the diode Dl quite a
  • circuit of Figure 2a further includes a control and / or regulating unit SR is provided, which sets the timing of the first switch Sl to control the LED power.
  • the control unit SR uses to set the exact turn-on and turn-off timing of the first one
  • Switches Sl as input signals from a first sensor unit SEI and / or signals from a second
  • the first sensor unit SEI is in series with the first
  • Switch Sl arranged and detects the flow of current through the first switch Sl. This serves to monitor the current flow through the first switch Sl. If the current flow through the first switch Sl exceeds a certain maximum reference value, the first switch S1 is switched off.
  • the first sensor unit SEI may be, for example, a measuring resistor (shunt or current measuring resistor). To monitor the current flow can now the
  • Voltage drop at the measuring resistor (shunt) are tapped and compared for example by means of a comparator with a reference value.
  • the second sensor unit SE2 is within the
  • the second sensor unit SE2 can monitor the current flow through the LED during the turn-off phase of the first switch (ie the freewheeling hare), for example by means of a series with the LED
  • control unit / control unit SR can set a suitable time for the switch-on time of the first switch S1.
  • Switches S1 are then turned on when the current through the coil LI for the first time is zero or at least very low, for example in the time domain, when the diode Dl locks at the end of the freewheeling phase. It can be present at the switch-on time of the first switch Sl the lowest possible current at the switch Sl. By detecting the current zero crossing through the coil LI almost lossless switching is possible. The current through the
  • LEDs show only a slight ripple and does not fluctuate greatly. This is due to the smoothing effect of the parallel to the LED capacitor C1.
  • the capacitor Cl takes over the supply of the LED.
  • the enlarged view shows the current course within a low-frequency pulse packet NF PWM
  • Switch S1 is switched off, in state 1 the switch is closed; the signals for the state of the switch Sl correspond to the drive signal (ie at the gate) of the
  • i_LED differs from i_L in that part of the current i__L contributes to the charge of the capacitor Cl.
  • the opening of the first switch Sl at time t_l (for example, when a desired maximum
  • the current i_LED decreases only weakly and is maintained, since the capacitor Cl has a smoothing effect.
  • the diode blocks.
  • the current i_L decreases (but is still negative) and goes to zero.
  • parasitic capacitances at the diode Dl and other parasitic capacitances in the rest of the circuit are reloaded.
  • the coil LI is not or hardly magnetized.
  • the first switch Sl can be turned on at this time with very low losses, since hardly any current through the coil LI flows. A reconnection is also already possible at the time t_2 or shortly before, because the current through the coil LI is very low in this time range.
  • a second sensor unit SE2 is now used for detecting the advantageous switch-on time for the first switch Sl.
  • the current i_L can be detected by the coil LI.
  • the current i_L through the coil LI can be detected, for example, by means of a Hall sensor. Additionally or alternatively, therefore, other / other variables can be used which are suitable for detecting an advantageous switch-on time.
  • the magnetization state of the coil LI can be detected.
  • the second sensor unit SE2 may be a secondary winding L2 on the coil LI, which taps the voltage across the coil LI.
  • Demagnetization (and thus the zero crossing) can be detected by exceeding or falling below a threshold value.
  • the voltage at the node Ux be monitored above the first switch Sl.
  • the voltage at node Ux drops significantly from a high value to a low value when the diode is turned off.
  • Switch Sl can therefore be triggered below the voltage Ux below a certain threshold.
  • the control unit SR turns on the first switch Sl again at the time when the coil LI
  • the second sensor unit SE2 can consist of a inductively coupled to the coil LI secondary winding L2 or from a voltage divider (Rl, R2) at the node Ux.
  • the control unit SR uses the information from the first sensor unit SEI and / or the second
  • the regulation of the (time-averaged) LED power by SR can, for example, be in the form of pulsed signals,
  • PWM signals done for example, PWM signals done.
  • the frequency of the pulsed signal is typically in the
  • the control unit SR may turn on the first switch S1 upon reaching a restart condition.
  • the control unit SR may turn off the first switch S1 upon reaching a turn-off condition.
  • Switch-off condition can be adjustable depending on the current dimming level.
  • the reclosing condition may be the expiration of a
  • Restart condition a monitored at the operating circuit voltage, preferably the voltage at a inductively coupled to the coil LI secondary winding L2, his.
  • the switch-off condition can be the expiration of a
  • the switch-off condition may be a current monitored by the operating circuit, preferably the current through a measuring resistor shunt, RS.
  • first sensor unit SEI which is one of the current through the first switch Sl
  • the first sensor unit SEI can generate the switch-off condition with the first sensor signal SES1.
  • the switch-off condition may be a current monitored at the operating circuit, preferably the current through a measuring resistor shunt, RS, which is connected in series with the first switch S1.
  • the first sensor unit SEI can be formed in this case by the measuring resistor shunt, RS, which is connected in series with the first switch Sl.
  • the switch-off condition may be the achievement of a
  • Off current value for a monitored at the operating circuit current for example, the current through the LED or the current through the first switch Sl.
  • the second sensor unit SE2 may be a second sensor unit SE2, which detects, for example, the achievement of the demagnetization of the coil LI and generates a sensor signal SES2.
  • the second sensor unit SE2 can also monitor the current flow through the LED during the turn-off phase of the first switch (that is, the freewheeling phase), for example with the aid of a series-connected LED
  • the second sensor unit SE2 can with the second sensor signal SES2 the
  • Restart condition may be the achievement of
  • an inrush current value 1 (in this case falling short) for a current monitored in the operating circuit.
  • the current through the LED or the current through the coil LI during the freewheeling hare, ie the turn-off of the first switch Sl, are monitored.
  • the current through the LED or the current through the coil LI during the freewheeling hare, ie the turn-off of the first switch Sl are monitored.
  • a waiting time can be inserted, which is adjusted depending on the dimming level, so depending on dimming level not immediately upon detection of the achievement of the demagnetization of the coil LI
  • the sensor signals SES1, SES2 can be connected to the
  • Control unit SR supplied and at the
  • Control unit SR are processed.
  • the switch-off condition can be increased as the dimming level increases and can not be reduced further if the dimming level falls below a certain level. Alternatively or additionally, the
  • Reclosing condition can be increased with increasing dimming level and not be further reduced when falling below a certain dimming level.
  • the control unit SR can achieve both the achievement of the switch-off condition and the achievement of the
  • Control / regulation unit SR can, for example, store value tables for different dimming levels and associated values for the switch-off condition and / or switch-on condition. In the control / regulation unit SR, for example, functions for a computational
  • a method is also provided for operating at least one LED, wherein the reclosing condition and / or the disconnecting condition may be adjustable depending on the current dimming level.
  • the brightness of the LED at low dimming levels can be adjusted both by adjusting the
  • Switching condition depends on the current dimming level, an adjustment of the average power or the average current through the LED and thus the brightness be adjusted. But it would also be possible for that
  • Restart condition and / or the off condition is not further adapted, but only the
  • FIG. 3 shows a special embodiment of the above-described switching arrangement (a Buck converter).
  • Switch-off is detected by detecting the voltage at the node Ux above the first switch Sl. This is done by the ohmic
  • the node Ux is located between the coil LI, the diode Dl and the switch Sl.
  • a voltage divider is, for example, a
  • the measuring resistor (shunt) RS is used for current detection by the first switch Sl.
  • the voltage at node Ux drops significantly from a high value to a low value when the diode is turned off.
  • the signal for reconnecting the first switch Sl can therefore be triggered below the voltage Ux below a certain threshold.
  • a second switch S2 is parallel to the LEDs and the
  • Capacitor Cl is arranged.
  • the second switch S2 is selectively / independently controllable and may for example be a transistor (MOSFET or bipolar transistor). If the second switch S2 is closed, the
  • Discharge process of the capacitor Cl accelerates. Due to the accelerated discharge of the capacitor Cl is achieved that the current flow through the LED goes to zero as quickly as possible. This is for example at the end of a
  • Low-frequency PWM packets are very short and it is important that the current through the LED at the end of a pulse packet quickly goes to zero. For example, an even lower dimming level can be achieved by suitable activation of the second switch S2.
  • Another function of this second switch S2 is that it bridges the LEDs when switched on. This is necessary, for example, when the LEDs are to be switched off, ie, to emit no light, but the supply voltage U0 is still present. Without bridging by the second switch S2, a (smaller) current would flow across the LEDs and resistors R1 and R2, and the LEDs would (slightly) light up.
  • Switch S2 parallel to the LEDs and the capacitor Cl for accelerated discharge of the capacitor Cl or for bridging the LED not only on the specific
  • Embodiment of the circuit arrangement of Figure 3 is limited, but can be applied to all embodiments of the invention.
  • Figure 4 shows a modification of the circuit in Figure 3 in that the voltage monitoring takes place on the coil LI.
  • the voltage on the coil Sl can
  • a secondary winding L2 which is coupled to the coil Sl, (or an additional coil L2, which inductively couples to the coil LI) are detected.
  • a secondary winding L2 is now used. The monitoring of the temporal voltage profile at the coil LI (in particular the 'break-in' in the vicinity of the blocking of the diode Dl after the time t_2) allows a statement about the advantageous
  • the determination of the time point of the zero crossing or the demagnetization can also take place by means of a threshold value monitoring (on exceeding or exceeding a threshold value, in the case of monitoring by means of a secondary winding L2, the polarity of the voltage depends on the winding sense of the secondary winding L2 to the coil LI off).
  • Figure 5 shows a modification of the circuit of Figure 2a in that the arrangement of the inductor LI, the diode Dl and the orientation of the LED track is modified (forms flyback converter or buck-boost converter).
  • Demagnetization of the coil LI by monitoring the voltage across the winding L2 can be performed by a standard available control circuit IC.
  • This control circuit IC corresponds to or contains the control unit SR shown in FIG. 2 to 5, has an input to
  • control circuit IC has an output for driving a switch and other monitoring inputs.
  • a first of these monitoring inputs may be for the
  • Reference voltage can be used.
  • a second monitoring input can be used for monitoring the achievement of a maximum voltage or even using a voltage measurement on a resistor for monitoring the achievement of a maximum current.
  • a third monitoring input can be used to monitor another voltage or to activate and
  • control circuit IC monitors the current through the first switch S1 during the first time
  • the first switch Sl is opened. The default of opening the first
  • Switch's Sl required level of voltage can be determined by the specification of a reference value (i.e.
  • Reference voltage at the input 3 of the control circuit IC. For example, from a
  • Microcontroller can be given a reference voltage which is the height of the maximum across the measuring resistor (shunt) Rs permissible voltage and thus the maximum permissible by the first switch Sl current.
  • the microcontroller may output a PWM signal that is then smoothed by a filter 10 (eg, an RC element) and thus as
  • Microcontroller can control the amplitude of the signal at
  • Input 3 of the control circuit IC can be adjusted.
  • the control circuit IC can through the input 5 based on the monitoring of the voltage across a coil LI applied to the secondary winding L2 reaching the
  • This detection can be used as a reclosing signal.
  • the control circuit IC can turn on the first switch Sl by driving through the output 7.
  • the control circuit IC can be activated and / or deactivated by applying a voltage at the input 1.
  • This voltage for activating at input 1 can also change between a high and a low level, wherein at high level, the control circuit IC is activated and at low level, at least the activation of the first
  • Switch Sl interrupts.
  • This control of the input 1 can be done by a microcontroller. For example, in this way a low-frequency activation and deactivation of the control circuit IC and thus the Control of the first switch Sl can be achieved and thus the low-frequency control of the
  • a further reference voltage for the control circuit IC can also be preset via the amplitude of the signal present at this input. This voltage can, for example, the height of the maximum allowable current through the switch
  • Microcontrollers can together form the control unit SR.
  • the duty cycle of the first switch Sl can also be determined by another voltage measurement within the
  • control circuit IC can also be supplied with a voltage measurement Vsense.
  • Voltage divider R40 / R47 for example, a monitoring or measurement of the voltage at the junction between coil LI and LED done. This voltage measurement Vsense can either be another input of the
  • Control circuit IC as an additional variable additively fed to an already occupied input of the control circuit IC or an input of the microcontroller.
  • a system can be constructed in which on the one hand a simple control for dimming of LED by Low-frequency PM is enabled, on the other hand, a low-loss as possible high-frequency operation of the
  • the height of the maximum allowable current can be specified by the first switch Sl.
  • Microcontroller can control the dimming of the LED by low-frequency PWM via a signal which is fed to the input 1 of the control circuit IC.
  • microcontroller via a signal which is fed to the input 3 of the control circuit IC, the height of the maximum allowable current through the first switch Sl or the necessary
  • the operating circuit may further include another
  • Switch S2 included which is arranged so that this second switch S2 can bridge the LED.
  • the second switch S2 may further be arranged so that it can take over the current through an existing high-impedance voltage measuring path or a similar existing high-resistance circuit arrangement of the LED or interrupt it.
  • the second switch S2 can be additionally used only for dimming to a low dimming level.
  • the operating circuit due to the existing topology and control circuitry, is designed to limit the output voltage of the operating circuit (i.e., the voltage across the LED) to a maximum allowable value. If the LED is bridged by closing the second switch S2, then the operating circuit limits the output voltage such that no excessive current can flow, which can lead to possible destruction. This activation of the second switch S2 can be used, for example, only for dimming to a low dimming level.
  • Switch S2 which should be very low impedance, are dimmed, and the losses are still low.
  • the second switch S2 can be controlled so that the current through an existing
  • high-impedance voltage measuring path or similar existing high-impedance circuit arrangement can take over from the LED.
  • the second switch S2 can be closed, so that the current flow through the LED is interrupted or avoided.
  • the second switch S2 can at least always be triggered following a low-frequency PWM packet in order to bridge or deactivate the LED (during the last discharge edge, ie at the end of a
  • An interruption of the current through the LED can also be done by arranging the second switch S2 in series with the LED.
  • control circuits IC and the control units SR of the individual operating circuits are controlled by a common microcontroller.
  • Operating circuits can drive, for example, LED strands of different wavelength or color.
  • the control of the microcontroller can via a
  • FIG. 7 shows a circuit arrangement - inter alia - a buck converter (buck converter) for the operation of at least the LED track (with one or more series-connected LEDs), with a first switch Sl, which also serves as a converter switch of Buck converter can be called.
  • the circuit arrangement also referred to below as the operating circuit, is supplied with a DC voltage or a rectified AC voltage U 0 .
  • the voltage U R0 can be measured, which can be closed to the DC voltage or a rectified AC voltage U 0 , and with the aid of the average current I s , the performance of the circuit can be determined.
  • the switch current can be detected by the first switch S1 at the measuring resistor RS, for example by the control / regulating unit SR.
  • the further exemplary embodiment according to FIG. 7 likewise relates to an operating circuit for at least one LED which has a DC voltage or rectified
  • the operating circuit is by means of a coil LI and one by a
  • Control / SR SR clocked first switch Sl a supply voltage for at least one LED ready.
  • the first switch Sl When the first switch Sl is energized in the coil LI an energy stored at switched off the first switch Sl via a diode Dl and at least one LED discharges.
  • first sensor unit SEI which is one of the current through the first switch Sl
  • the dependent first sensor signal SES1 generated.
  • the sensor signals SES1, SES2 can be supplied to the control unit SR and
  • control / regulating unit SR turns on the first switch Sl at the time when the coil LI is demagnetized and / or the diode Dl blocks.
  • the control unit SR turns off the first switch Sl at the time when the current through the first switch Sl exceeds a threshold value SW.
  • the control unit SR detects the average current
  • Threshold SW on The reference value can be set depending on the current dimming level.
  • the average current (is_meaning) can be determined by a
  • Low pass filter can be detected at the measuring resistor Rs, the low pass filter (LPF) can be detected during the pulse pause of the low-frequency PWM signal NF PWM be separated by means of a third switch S3.
  • the threshold SW of the operating circuit is
  • the threshold SW of the operating circuit can at
  • the threshold value SW is increased as the dimming level increases. This increase in the threshold SW as the increase in
  • Dimming curve is a change according to a predetermined non-linear transfer function.
  • the timing of the first switch Sl becomes for a certain period of time
  • the timing of the first switch Sl is for a
  • this period is not shortened when a certain dimming level is exceeded.
  • both the timing of the first switch Sl is interrupted for a certain period of time, this period with
  • this period is increased nonlinearly when lowering the dimming level.
  • About the dimming curve is a change according to a predetermined
  • the control unit SR uses a signal SES1 of the first sensor unit SEI or a signal SES2 of the second one
  • Sensor unit SE2 or a combination of a signal SESL from the first sensor unit SEI and a signal SES2 from the second sensor unit SE2 to determine the on and off timing of the first switch Sl.
  • the first switch Sl is turned off when the current through the first switch Sl exceeds a maximum reference value.
  • the first sensor unit SEI can be a measuring resistor shunt, RS.
  • the second sensor unit SE2 can consist of a secondary winding L2 which is inductively coupled to the coil LI.
  • the second sensor unit SE2 detects the reaching of
  • the control circuit IC can via an input to
  • a microcontroller can activate and / or deactivate it and specify a reference voltage for the control circuit IC at a further input.
  • Another example similar to the previous examples, concerns an operating circuit for at least one LED that is DC or rectified
  • a capacitor C1 disposed in parallel with the at least one LED and capable of maintaining the current through the LED during the demagnetization phase of the coil LI. It may be a first
  • Sensor unit SE2 be present, which detects the achievement of the demagnetization of the coil LI and a
  • Sensor signal SES2 generated.
  • the sensor signals SES1, SES2 can be supplied to the control unit SR and
  • the control unit SR may turn on the first switch S1 at the time when the coil LI is demagnetized and / or the diode Dl is off.
  • the control unit SR may turn off the first switch S1 at the time when the current through the first switch Sl exceeds a threshold value SW, and the threshold value SW may be adjustable depending on the current dimming level.
  • first switch Sl provides a supply voltage for at least one LED.
  • first switch Sl When the first switch Sl is energized in the coil LI an energy that discharges when switched off the first switch Sl via a diode Dl and at least one LED.
  • Control unit SR may turn on the first switch S1 upon reaching a reclosing condition.
  • the control unit SR may turn off the first switch S1 upon reaching a turn-off condition.
  • the restart condition and / or the switch-off condition may be adjustable depending on the current dimming level.
  • the reclosing condition may be the expiration of a
  • Restart condition a monitored at the operating circuit voltage, preferably the voltage at a inductively coupled to the coil LI secondary winding L2, his.
  • the switch-off condition can be the expiration of a
  • the switch-off condition may be a current monitored by the operating circuit, preferably the current through a measuring resistor shunt, RS.
  • a first sensor unit SEI which is one of the current through the first switch Sl
  • the first sensor unit SEI can generate the switch-off condition with the first sensor signal SES1.
  • the switch-off condition may be a current monitored at the operating circuit, preferably the current through a measuring resistor shunt, RS, which is connected in series with the first switch S1.
  • the first sensor unit SEI can be formed in this case by the measuring resistor shunt, RS, which is connected in series with the first switch Sl.
  • the switch-off condition may be the achievement of a
  • Off current value for a monitored at the operating circuit current for example, the current through the LED or the current through the first switch Sl.
  • the second sensor unit SE2 may be a second sensor unit SE2, which detects, for example, the achievement of the demagnetization of the coil LI and generates a sensor signal SES2.
  • the second sensor unit SE2 can also monitor the current flow through the LED during the turn-off phase of the first switch (that is, the freewheeling phase), for example with the aid of a series-connected LED
  • the second sensor unit SE2 can with the second sensor signal SES2 the
  • the reclosing condition may be the achievement of
  • the sensor signals SES1, SES2 can be connected to the
  • Control unit SR supplied and at the
  • Control unit SR are processed.
  • the switch-off condition can be increased as the dimming level increases and can not be reduced further if the dimming level falls below a certain level.
  • the reclosure condition may be at
  • Increasing dimming level can be increased and not be reduced below a certain dimming level.
  • a method is also provided for operating at least one LED, wherein the reclosing condition and / or the disconnecting condition may be adjustable depending on the current dimming level.
  • the low-frequency PWM signal NF PWM is a low-frequency pulse signal, wherein the turn-off of this signal determines the specific period in which the first switch Sl is not clocked but its timing is interrupted.
  • a method for at least one LED is enabled, which is supplied to a DC voltage or rectified AC voltage and by means of a coil LI and one by a
  • Control / SR SR clocked first switch Sl provides a supply voltage for at least one LED, wherein when the first switch Sl in the coil LI an energy is temporarily stored, which discharges when the first switch Sl via a diode Dl and at least one LED, wherein optional on
  • Capacitor Cl is present, which is parallel to the
  • At least one LED is arranged, and maintains the current through the LED during the demagnetization phase of the coil LI.
  • a first sensor unit SEI generates a current through the first switch Sl
  • the sensor signals SES1, SES2 are supplied to the control unit SR and processed there, wherein the control / SR unit switches the first switch S1 back on at the time when the coil LI is demagnetized and / or the diode Dl blocks, the control / Control unit SR turns off the first switch Sl at the time when the current through the first switch Sl exceeds a threshold SW, and the threshold SW is adjustable depending on the current dimming level.
  • the current dimming level can be supplied to the operating device, in particular via a wired or wireless interface, as an externally preset desired brightness value, for example.
  • the current dimming level can also be predefined on the basis of a measurement of a sensor, for example a brightness sensor, this dimming level being determined, for example, by the operating device as a function of the detected voltage level
  • Ambient brightness can be adjusted.

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

L'invention concerne un circuit d'exploitation pour au moins une diode électroluminescente (DEL), qui reçoit une tension continue ou une tension alternative redressée et qui, à l'aide d'une bobine (L1) et d'un premier commutateur (S1) cadencé par une unité de commande et de régulation (SR), fournit une tension d'alimentation pour au moins une diode DEL. Lorsque le premier commutateur (S1) est passant, la bobine (L1) assure un stockage intermédiaire de l'énergie qui, lorsque le premier commutateur (S1) est bloquant, se décharge par une diode (D1) et par au moins une diode DEL. L'unité de commande et de régulation (SR) fait passer le premier commutateur (S1) à l'état passant lorsqu'une condition de remise à l'état passant est atteinte et fait passer le premier commutateur (S1) à l'état bloquant lorsqu'une condition de mise à l'état bloquant est atteinte. La condition de remise à l'état passant et/ou la condition de mise à l'état bloquant peuvent être réglées en fonction du niveau de variation courant.
EP14731538.6A 2013-04-30 2014-04-30 Circuit d'exploitation pour diodes électroluminescentes Withdrawn EP2992735A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AT1512013 2013-04-30
ATGM353/2013U AT14074U1 (de) 2013-04-30 2013-10-28 Betriebsschaltung für LED
PCT/AT2014/000096 WO2014176609A1 (fr) 2013-04-30 2014-04-30 Circuit d'exploitation pour diodes électroluminescentes

Publications (1)

Publication Number Publication Date
EP2992735A1 true EP2992735A1 (fr) 2016-03-09

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Application Number Title Priority Date Filing Date
EP14731538.6A Withdrawn EP2992735A1 (fr) 2013-04-30 2014-04-30 Circuit d'exploitation pour diodes électroluminescentes

Country Status (5)

Country Link
US (1) US9655182B2 (fr)
EP (1) EP2992735A1 (fr)
AT (1) AT14074U1 (fr)
DE (1) DE112014002232B4 (fr)
WO (1) WO2014176609A1 (fr)

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AT16867U1 (de) 2015-02-24 2020-11-15 Tridonic Gmbh & Co Kg Abwärtswandler zum Betreiben von Leuchtmitteln mit Spitzenstromwertsteuerung und Mittelstromwerterfassung
DE102015203249A1 (de) * 2015-02-24 2016-08-25 Tridonic Gmbh & Co. Kg Abwärtswandler zum Betreiben von Leuchtmitteln mit Spitzenstromwertsteuerung und Mittelstromwerterfassung
DE102015210710A1 (de) 2015-06-11 2016-12-15 Tridonic Gmbh & Co Kg Getaktete Sperrwandlerschaltung
DE202017101093U1 (de) 2017-02-27 2018-05-29 Tridonic Gmbh & Co Kg Schaltregler zum Betreiben von Leuchtmitteln
GB201711699D0 (en) 2017-07-20 2017-09-06 Univ Bristol Microfluidics analysis system

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KR100628716B1 (ko) * 2005-02-02 2006-09-28 삼성전자주식회사 Ｌｅｄ구동장치
KR100674867B1 (ko) * 2005-05-18 2007-01-30 삼성전기주식회사 과전류/과전압 보호 기능을 갖는 직류-직류 컨버터 및 이를구비한 ｌｅｄ 구동회로
DE102006034371B4 (de) 2006-04-21 2019-01-31 Tridonic Ag Betriebsschaltung und Betriebsverfahren für Leuchtdioden
WO2007141741A1 (fr) 2006-06-08 2007-12-13 Koninklijke Philips Electronics N.V. Circuits pour effectuer une gradation de lumière de dispositifs d'éclairage à diodes led
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EP2345308B1 (fr) * 2008-10-20 2012-08-29 Tridonic AG Circuit de fonctionnement destiné à des led
WO2010045666A1 (fr) * 2008-10-20 2010-04-29 Tridonicatco Gmbh & Co Kg Circuit de commande pour diodes électroluminescentes
WO2010118944A1 (fr) * 2009-04-14 2010-10-21 Tridonic Gmbh & Co Kg Régulation de la puissance de del, à l'aide de la moyenne du courant des del et d'un compteur bidirectionnel
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Also Published As

Publication number Publication date
US20160081150A1 (en) 2016-03-17
AT14074U1 (de) 2015-04-15
DE112014002232A5 (de) 2016-02-04
WO2014176609A1 (fr) 2014-11-06
DE112014002232B4 (de) 2024-04-18
US9655182B2 (en) 2017-05-16

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