WO2010015999A1 - Convertisseur à courant de sortie régulé - Google Patents

Convertisseur à courant de sortie régulé Download PDF

Info

Publication number
WO2010015999A1
WO2010015999A1 PCT/IB2009/053380 IB2009053380W WO2010015999A1 WO 2010015999 A1 WO2010015999 A1 WO 2010015999A1 IB 2009053380 W IB2009053380 W IB 2009053380W WO 2010015999 A1 WO2010015999 A1 WO 2010015999A1
Authority
WO
WIPO (PCT)
Prior art keywords
current
duration
transformer
switching
duty cycle
Prior art date
Application number
PCT/IB2009/053380
Other languages
English (en)
Inventor
Gert-Jan Koolen
Araldo Van De Kraats
Original Assignee
Nxp B.V.
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 Nxp B.V. filed Critical Nxp B.V.
Publication of WO2010015999A1 publication Critical patent/WO2010015999A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters

Definitions

  • the present invention relates in general to the field of circuits for providing a controlled output current, in particular to power converter circuits and more particular to flyback converter circuits providing a controlled output current. Further, the present invention relates to a respective current control method.
  • the present invention relates to a converter circuit providing a controlled output current for driving a light emitting diode device. More particular, the present invention relates to a system comprised of such a converter circuit and light emitting diode device as well as to a respective replacement system for conventional candescent lamps.
  • LED Light-emitting diodes
  • LED are semiconductor diodes that by means of electroluminescence emit incoherent narrow-spectrum light when electrically biased in the forward direction of their pn-junction, as in the common LED circuit.
  • the range of use and application for LED's starts from small area light sources, often with added optics to shape the radiation pattern and/or assist in reflection, up to high power applications such as flashlights and area lighting.
  • the color of the emitted light goes from infrared via the visible range up to ultraviolet and depends on the composition and condition of the semi- conducting material used. More and more, LED's are entering the consumer market as a regular household light source. Besides new developed applications based thereon, LED's are entering in the huge replacement market for incandescent lamps. Accordingly any suitable electronics enabling LED application have to comply with demanding critical requirements for size, in particular the "must-fit" requirement in respect to existing sockets, and of course the aspect of cost when thinking about a high volume "off-the-shelf consumable.
  • flyback converters are one suitable driver topology due to their simplicity, efficiency and ability to provide electric isolation by means of a flyback-transformer. Since LED's require a specific current to operate, there is the need to control the current through the isolation.
  • a usual solution employs an optocoupler device to provide feedback from the secondary side to the primary side of the flyback-transformer where the switching controller usually is located.
  • optocouplers are both expensive and space consuming, while both aspects are critical design parameters, as mentioned above, and thus, are desired to be minimized.
  • Fig. 1 shows a typical arrangement 100 for supply of a regulated current to a LED device 110 via a stage 120 for rectifying and smoothing the current supplied by the flyback converter 100, which stage is comprised of an known arrangement of a diode D in the current path and a energy storing capacitor C connected in parallel to the LED device 110.
  • the desired afore-mentioned isolation is provided by means of a flyback-transformer 102 having a primary winding P at its primary/input side and a secondary winding S at its secondary/output side.
  • a current detection circuit 104 measures the instantaneous secondary current Is in the LED device 110 by means of a sensing resistor Rs.
  • An optocoupler 106 implements a feedback path for providing the measurement information on the secondary current to a fly back controller 108.
  • the flyback controller 108 controls a switching transistor 109, wherein by means of the applied switching frequency and duty cycle of the switching operation controls the energy supplied into the primary side by the primary current Ip of the fly back transformer and thus to the secondary side thereof.
  • Fig. 1 suffers from two major disadvantages. Firstly, the employed optocoupler is expensive and bulky resulting in increased cost as well as size of such a converter. Secondly, for sensing the secondary current Is a measurement element such as a resistor is used in the secondary high current path of the transformer. This reduces efficiency due to energy losses. For the application area these factors are extremely important.
  • US 2007/0121349 Al discloses a transformer-isolated flyback converter for delivering regulated power and current to an output load.
  • the flyback- transformer has a primary winding and a secondary winding for delivering stored energy to the output load.
  • An oscillator circuit is provided for generating a periodical signal.
  • a switching circuit is coupled to the flyback-transformer and the oscillator circuit for energizing the primary winding to a reference current level each cycle of the oscillator circuit.
  • the oscillator circuit has an integrator for deriving a time integral of a voltage at the primary winding.
  • the oscillator circuit further comprises a peak detector coupled to the integrator for holding a peak value of the time integral.
  • the oscillator circuit furthermore has a ramp generator for producing a ramp signal.
  • a comparator is provided for comparing the peak value with the ramp signal and generating the periodical signal whenever the ramp signal exceeds the peak value.
  • the object is achieved by switching power converter circuit for supply of a controlled output current to a load, in particular a light emitting diode device, according to claim 1.
  • the circuit comprises: a transformer element having a first primary winding for receiving electric energy from an input power source, at least one secondary winding for delivering said energy to the load coupled to thereto, and a second primary winding for sensing of the magnetization of the transformer; at least one switching element for switching a primary current path comprising the first primary winding, wherein the switching is controlled by a control unit of the circuit; and at least one current sensing element for sensing the current in the primary current path; wherein the control unit is configured to adjust a duty cycle of the switching element, which duty cycle is comprised of a first duration, in which the switching element is closed, to supply electrical energy from the input source to the first primary winding, and a second duration, in which the switching element is open, based on at least the current level and on the magnetization of the transformer.
  • the controller unit may be configured to start a next first duration consecutive after termination of the second duration.
  • the converter further comprises a comparator unit for comparing a signal produced by the at least one current sensing element with a predetermined reference value corresponding to an amount of energy to be supplied into the first primary winding.
  • An output of the comparator unit is provided to the controller unit, which is further configured to set the first duration in accordance to the output.
  • the second primary winding is coupled to the control unit, which is further configured to define the second duration so that the magnetization of the transformer can decrease to a predetermined magnetization value.
  • the predetermined magnetization value is substantially zero. In other words, the converter waits until the transformer is out of energy, which happens sooner if more current is drawn. Thus, the output current is controlled.
  • the converter circuit is fairly simple to implement. It is to be noted that in this embodiment the converter operates at a variable switching frequency, which is determined by first and second durations.
  • the converter is operated with a constant switching cycle time and the controller unit is configured to control the second duration to the difference between the switching cycle time and the first duration.
  • the converter further comprises a measurement unit, to which the second primary winding is coupled.
  • the measurement unit can be configured to measure the demagnetization time, which starts at the end of the first duration and lasts until the magnetization of the transformer has decrease to a predetermined magnetization value.
  • the measurement unit, or any other suitable part of the circuit such as the controller unit can be configured to produce a duty cycle adjustment factor based on the switching cycle time and the measured demagnetization time.
  • the signal produced by the at least one current sensing element can then be adjusted or compensated by means of the produced duty cycle adjustment factor; alternatively, the predetermined reference value corresponding to the amount of energy to be supplied into the first primary winding can be adjusted by means of the produced duty cycle adjustment factor.
  • the duty cycle adjustment factor corresponds the product of the switching frequency and the measured second duration.
  • the measurement unit or any other suitable part of the circuit such as the controller unit, can be configured to adjust or compensate the signal produced by the at least one current sensing element by multiplying it with the duty cycle adjustment factor; again, the predetermined reference value corresponding to the amount of energy to be supplied into the first primary winding can alternatively be adjusted by means of the produced duty cycle adjustment factor.
  • the object is further achieved by a system, according to claim 8.
  • the system comprises a converter circuit according to the invention and at least one light emitting diode device coupled to the output of said converter circuit for receiving the controlled output current from said converter.
  • the replacement system for a incandescent lamp device configured for fitting in a predetermined socket for said incandescent lamp device, which system comprises: a plug portion configured for fitting to the predetermined socket and for connecting to power supply contacts provided in said socket, and a system comprising a converter circuit according to the invention and at least one light emitting diode device coupled to the output of said converter circuit for receiving the controlled output current from said converter.
  • the object is further achieved by a method for driving a load, in particular a light emitting diode device with a controlled output current, in accordance with claim 10.
  • electric energy is received from an input power source by a first primary winding of a transformer element, electric energy is delivered by at least one secondary winding of the transformer to said load coupled to thereto, and a primary current path comprising the first primary winding is switched.
  • the method further comprises: sensing the current in the primary current path; sensing the magnetization of the transformer by a second primary winding of said transformer; adjusting a duty cycle of the switching of the primary current path so that the duty cycle is comprised of a first duration, in which the switching element is closed and electrical energy is supplied from the input source to the first primary winding, and of a second duration, in which the switching element is opened, based on at least the sensed current level and on the sensed magnetization of the transformer.
  • the method comprises comparing the sensed current level with a predetermined reference value corresponding to an amount of energy to be supplied into the first primary winding, controlling the first duration based on the result of the comparing step, and defining the second duration so that the magnetization of the transformer can decrease to a predetermined magnetization value.
  • the method further comprises: performing the switching of the primary current path with a constant switching cycle time, defining the second duration to be the difference between the switching cycle time and the first duration, measuring the demagnetization time, starting at the end of the first duration and lasting until the magnetization of the transformer has decreased to a predetermined magnetization value, and adjusting the sensed current level with a duty cycle adjustment factor based on the switching cycle time and the measured demagnetization time.
  • the adjusting of the sensed current level may in particular comprise multiplying the switching frequency and the measured demagnetization time to produce the duty cycle adjustment factor, and compensating the sensed current level with the duty cycle adjustment factor.
  • the method may comprise adjusting the predetermined reference value corresponding to the amount of energy to be supplied into the first primary winding by means of the produced duty cycle adjustment factor.
  • the basic concept of the invention resides in the idea to control the current at the secondary side of the transformer without need for information on the secondary current. Accordingly, the actual duty cycle can be adjusted firstly, by waiting for transformer demagnetization during the time in which the switching element of the flyback converter is open, and secondly, by using the duty cycle of the secondary side to adjust the switching peak current.
  • the invention employs a transformer primary side measurement to substitute for the secondary side current measurement, as e.g. used in the prior art arrangement of Fig. 1.
  • energy quantization can be provided by a switching means driven with a duty cycle adjusted based on the primary side current measurement.
  • the variable switching frequency can be implemented based on transformer demagnetization, wherein a first duration or stroke, where the switching means are closed, has fixed time and a second duration or stroke, where the switching means are open, is varied.
  • the switching frequency is kept fixed, but the duty cycle is adjusted based on a switching peak current in the primary current path.
  • the end of the first duration is modified depending on the duty cycle of the secondary side, which may be defined as the time as long as current flows through the secondary winding divided by the total cycle time; note, substantial no current flows through the secondary winding, when the second primary winding senses demagnetization of the transformer.
  • Fig. 1 illustrates prior art flyback converter arrangement with secondary current measurement and optocoupler in a feedback path
  • Fig. 2 shows a flyback converter arrangement according to the present invention
  • Fig. 3 shows a further development of the flyback converter arrangement according to the present invention
  • Fig. 4 illustrates a switching cycle period of the switching control signal of the converter of the invention, in particular parameters for adjusting the duty cycle
  • Fig. 5 depicts a flow chart illustrating the steps of a method for load current control in accordance to the present invention.
  • the actual duty cycle can be adjusted firstly, by waiting for transformer demagnetization during the time in which the switching element of the flyback converter is closed, and secondly, by using the duty cycle of the secondary side to adjust the switching peak current.
  • the flyback converter arrangement 200 is configured to supply a regulated current to a LED device 210 via a stage 220 for rectifying and smoothing the current supplied by the flyback converter 200.
  • the rectifying and smoothing stage 220 can be of any known kind and is by way of example depicted as comprised of a diode D in the current path and an energy storing capacitor C connected in parallel to the LED device 210. Isolation is provided by means of the flyback-transformer 202 having a primary winding Pl at its primary/input side and a secondary winding S at its secondary/output side.
  • the flyback controller 208 controls a switching means 209 for control of the primary or input current of the transformer 202.
  • the switching means can be implemented as a semiconductor switch such as a switching transistor T.
  • As input parameters for control of the secondary current the flyback controller 208 gets information on the current in the primary side/winding Pl of the transformer 202 and information on the magnetization of the transformer by means of a auxiliary, e.g. a second primary, winding P2.
  • the converter 200 operates at a variable frequency, which is determined by inversion of the resultant cycle time T tot ai comprised of the duration tl of stroke Sl and the duration t2 of stroke S2 (cf. Fig. 4). At every cycle of the flyback converter 200 a distinct amount of energy is transferred to the transformer 202 during duration tl of stroke Sl, and from the transformer to the LED device 210 during duration t2 of stroke S2.
  • a precise/predetermined amount of energy is transferred into the transformer 202.
  • the second stroke S2 it is waited for demagnetization of the transformer 202 before proceeding to or starting the next cycle.
  • demagnetization of the transformer is monitored by means of the auxiliary or second primary winding P2.
  • demagnetization can be detected by waiting for a zero crossing, i.e. the voltage becoming zero. Only then, it is preceded to the next first stroke.
  • FIG. 3 shows a flyback converter arrangement 300 in accordance to a further development of the invention. In the following only the differences in comparison to the arrangement of Fig. 2 are described.
  • the signal of the second primary winding or auxiliary winding P2 of the transformer 202 is supplied to a duty cycle measurement unit 230, which is configured to determine the duty cycle of the secondary side and to generate a correction or adjustment factor for adjusting of the duty cycle of the switching means 209, in particular by adjusting the switching peak current in the primary side of the flyback transformer 202.
  • the duty cycle of the controller is adjusted, but further the overall switching frequency is kept constant, i.e. the converter 300 operates at a fixed frequency.
  • the voltage level Vthr at which stroke Sl ends is modified depending on the duty cycle of the secondary side, which is defined as the time during which current flows through the secondary winding divided by the total cycle time T to tai-
  • the peak current at which the switching transistor 209 as switching means stops conducting is modulated by the duty cycle of the secondary side.
  • a switching cycle period T tot ai of the switching control signal of the converter of the invention in particular the parameters for adjusting the duty cycle thereof is illustrated.
  • the converter operates at a variable frequency, which is determined by the first and second duration tl, t2.
  • a distinct amount of energy is transferred during the duration tl to the transformer, and from the transformer to the load during duration t2. That is to say, by monitoring the current in the primary winding of the transformer, e.g. by means of a voltage over a resistor in the primary current path (Rl in Fig. 2 and 3), duration tl ends, when the predetermined current/voltage level is reached, i.e.
  • duration tl is constant as long as the distinct amount of energy to be transferred and/or the primary input voltage is/are not altered. Duration t2 last as long as the transformer requires for demagnetization. That is to say, it is then proceed to the next cycle, when no substantially no current flows in the secondary winding of the transformer.
  • the control of the output current is basically achieved by adjusting the switching cycle time T tot ai accordingly (cf. 0 in
  • the converter is operated at a fixed frequency, but the voltage level at which duration tl ends is modified depending on the duty cycle of the secondary side, which is defined as the time current flows through the secondary winding divided by the total cycle time (cf.
  • the duration tl can be adjusted by compensating the predetermined peak current level in the primary winding of the transformer, at which the supply of electrical energy to the transformer is stopped. This can be done by compensating the detected or sensed threshold for the current in the primary current path with this duty cycle correction factor, e.g. by using a multiplication. This results in that the current on the secondary side is constant, and that even the tolerance on the transformer inductance does not affect the output power.
  • step SlOO electric energy is received from an input power source by a first primary winding of a transformer element by closing a switch in the primary current path so that electrical current provided by the input power source can increase in the primary winding of the transformer.
  • the switch is opened when the current in the primary winding reaches a predetermined level.
  • step S200 the magnetization of the transformer is measured by means of an auxiliary winding, e.g. a second primary winding.
  • step S300 the method branches depending on whether the converter is operated with a constant switching cycle time or frequency or not.
  • step S400 in which second duration of the cycle time lasts until the transformer is substantially demagnetized, i.e. no current flows in/through the secondary winding thereof.
  • the second duration electric energy is delivered by the secondary winding of the transformer to a load coupled to thereto.
  • a new switching cycle is started, i.e. the method returns to step SlOO.
  • step S410 in which the demagnetization time is measured, which starts at the end of the first duration and lasts until the magnetization of the transformer has decreased to a predetermined magnetization value.
  • step S420 the second duration is set to the difference between the switching cycle time and the first duration.
  • step S430 a duty cycle adjustment factor is generated based on the switching cycle time and the measured demagnetization time of the transformer, which duty cycle adjustment factor is used to compensate the sensed current level in the primary current path in the next step SlOO.
  • the adjustment of the sensed current level may comprise multiplying the switching frequency and the measured demagnetization time to produce the duty cycle adjustment factor, and compensating the sensed current level with the duty cycle adjustment factor.
  • the reference value for the sensed current level may be adjusted instead.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Dc-Dc Converters (AREA)

Abstract

Dans un convertisseur à transfert indirect isolé pour circuits d'attaque de DEL, pour maintenir le courant constant, le circuit de commutation côté primaire doit généralement détecter le courant de sortie côté secondaire. Cette opération est généralement effectuée par un photocoupleur. L'invention porte sur l'introduction d'un montage convertisseur à transfert indirect dans lequel deux voies différentes peuvent être employées pour réguler le courant côté secondaire, sans requérir l’usage d'un photocoupleur. Le nouveau convertisseur à transfert indirect est particulièrement approprié pour attaquer des diodes électroluminescentes (DEL) qui, au lieu de la tension habituelle, requièrent une régulation de courant dont le prix est très élevé.
PCT/IB2009/053380 2008-08-06 2009-08-04 Convertisseur à courant de sortie régulé WO2010015999A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP08161897 2008-08-06
EP08161897.7 2008-08-06

Publications (1)

Publication Number Publication Date
WO2010015999A1 true WO2010015999A1 (fr) 2010-02-11

Family

ID=41226250

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2009/053380 WO2010015999A1 (fr) 2008-08-06 2009-08-04 Convertisseur à courant de sortie régulé

Country Status (1)

Country Link
WO (1) WO2010015999A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2375856A1 (fr) * 2010-04-08 2011-10-12 Helvar Oy Ab Dispositif à transformateur pour la protection de composants optoelectroniques
WO2011152795A1 (fr) * 2010-06-04 2011-12-08 Opulent Electronics International Pte Ltd Dispositif et procédé d'actionnement de del
WO2012103795A1 (fr) * 2011-02-01 2012-08-09 杭州士兰微电子股份有限公司 Commande d'alimentation à découpage avec pilotage à courant constant d'une del par commande côté primaire et procédé associé
CN102751877A (zh) * 2011-04-20 2012-10-24 Nxp股份有限公司 开关电路
AT13276U1 (de) * 2012-04-13 2013-09-15 Tridonic Gmbh & Co Kg LED-Konverter
CN109818507A (zh) * 2019-04-03 2019-05-28 深圳市必易微电子有限公司 过流保护补偿电路及方法以及反激电路

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5982640A (en) * 1998-02-03 1999-11-09 Philips Electronics North America Corporation Arrangement for reducing the effects of capacitive coupling in a control circuit for a switched-mode power supply
US20030174520A1 (en) * 2000-10-24 2003-09-18 Igor Bimbaud Self-oscillating control circuit voltage converter
WO2004112228A1 (fr) * 2003-06-19 2004-12-23 Koninklijke Philips Electronics N.V. Detection d'un courant d'aimantation
US20050067981A1 (en) * 2003-09-30 2005-03-31 International Rectifier Corporation Simplified topology for HID lamps
US20050073862A1 (en) * 2003-10-02 2005-04-07 Alexander Mednik Switching power converter and method of controlling output voltage thereof using predictive sensing of magnetic flux
US20050146903A1 (en) * 2004-01-05 2005-07-07 Ta-Yung Yang Power-mode controlled power converter
US20070121349A1 (en) * 2005-11-28 2007-05-31 Alexander Mednik Transformer-isolated flyback converters and methods for regulating output current thereof
US20080043496A1 (en) * 2006-08-15 2008-02-21 System General Corp. Linear-predict sampling for measuring demagnetized voltage of transformer

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5982640A (en) * 1998-02-03 1999-11-09 Philips Electronics North America Corporation Arrangement for reducing the effects of capacitive coupling in a control circuit for a switched-mode power supply
US20030174520A1 (en) * 2000-10-24 2003-09-18 Igor Bimbaud Self-oscillating control circuit voltage converter
WO2004112228A1 (fr) * 2003-06-19 2004-12-23 Koninklijke Philips Electronics N.V. Detection d'un courant d'aimantation
US20050067981A1 (en) * 2003-09-30 2005-03-31 International Rectifier Corporation Simplified topology for HID lamps
US20050073862A1 (en) * 2003-10-02 2005-04-07 Alexander Mednik Switching power converter and method of controlling output voltage thereof using predictive sensing of magnetic flux
US20050146903A1 (en) * 2004-01-05 2005-07-07 Ta-Yung Yang Power-mode controlled power converter
US20070121349A1 (en) * 2005-11-28 2007-05-31 Alexander Mednik Transformer-isolated flyback converters and methods for regulating output current thereof
US20080043496A1 (en) * 2006-08-15 2008-02-21 System General Corp. Linear-predict sampling for measuring demagnetized voltage of transformer

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2375856A1 (fr) * 2010-04-08 2011-10-12 Helvar Oy Ab Dispositif à transformateur pour la protection de composants optoelectroniques
WO2011152795A1 (fr) * 2010-06-04 2011-12-08 Opulent Electronics International Pte Ltd Dispositif et procédé d'actionnement de del
WO2012103795A1 (fr) * 2011-02-01 2012-08-09 杭州士兰微电子股份有限公司 Commande d'alimentation à découpage avec pilotage à courant constant d'une del par commande côté primaire et procédé associé
US9084318B2 (en) 2011-02-01 2015-07-14 Hangzhou Silan Microelectronics Co., Ltd. Primary-side controlled switch-mode power supply controller for driving LED with constant current and method thereof
CN102751877A (zh) * 2011-04-20 2012-10-24 Nxp股份有限公司 开关电路
EP2515426A1 (fr) * 2011-04-20 2012-10-24 Nxp B.V. A switching circuit
US9036375B2 (en) 2011-04-20 2015-05-19 Nxp B.V. Controller that determines average output current of a switching circuit
AT13276U1 (de) * 2012-04-13 2013-09-15 Tridonic Gmbh & Co Kg LED-Konverter
CN109818507A (zh) * 2019-04-03 2019-05-28 深圳市必易微电子有限公司 过流保护补偿电路及方法以及反激电路

Similar Documents

Publication Publication Date Title
US8729811B2 (en) Dimming multiple lighting devices by alternating energy transfer from a magnetic storage element
US8736194B2 (en) LED dimmer circuit
US9173261B2 (en) Secondary-side alternating energy transfer control with inverted reference and LED-derived power supply
US9215770B2 (en) Systems and methods for low-power lamp compatibility with a trailing-edge dimmer and an electronic transformer
JP6198733B2 (ja) 固体照明モジュールの主電源信号に基づく調光を実施するシステム及び方法
US8912781B2 (en) Integrated circuit switching power supply controller with selectable buck mode operation
US8319449B2 (en) Controlled voltage source for LED drivers
US9101010B2 (en) High-efficiency lighting devices having dimmer and/or load condition measurement
US9313840B2 (en) Control data determination from primary-side sensing of a secondary-side voltage in a switching power converter
US8749171B2 (en) Lighting apparatus and control method thereof
WO2010015999A1 (fr) Convertisseur à courant de sortie régulé
US8779682B2 (en) Illumination driving apparatus
US9184661B2 (en) Power conversion with controlled capacitance charging including attach state control
US10104729B2 (en) LED driver circuit, and LED arrangement and a driving method
EP2973969B1 (fr) Réduction de l'erreur de quantification dans les dispositifs de commande de courant de sortie constant
KR100820613B1 (ko) 조명용 저압 전원 회로, 조명 장치 및 조명용 저압 전원출력 방법
US8912732B2 (en) Current sensing for LED drivers
US20160242258A1 (en) Resistance measurement of a resistor in a bipolar junction transistor (bjt)-based power stage
KR102083332B1 (ko) 컨버터 조도 제어 장치 및 방법
US20080100231A1 (en) Circuit and method for driving light source
JP5275186B2 (ja) 照明用ｌｅｄ駆動回路
KR102083336B1 (ko) 컨버터 디밍 제어 장치 및 방법
JP7122628B2 (ja) 照明点灯装置、照明装置、及び照明器具
TWI672975B (zh) 發光元件驅動裝置及其驅動方法
CN117641655A (zh) 调光控制电路和led照明装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09786790

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09786790

Country of ref document: EP

Kind code of ref document: A1