WO2024256212A1 - Circuit d'éclairage à del et dispositif d'éclairage à del - Google Patents

Circuit d'éclairage à del et dispositif d'éclairage à del Download PDF

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Publication number
WO2024256212A1
WO2024256212A1 PCT/EP2024/065296 EP2024065296W WO2024256212A1 WO 2024256212 A1 WO2024256212 A1 WO 2024256212A1 EP 2024065296 W EP2024065296 W EP 2024065296W WO 2024256212 A1 WO2024256212 A1 WO 2024256212A1
Authority
WO
WIPO (PCT)
Prior art keywords
led
circuit
supply
voltage
led3
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.)
Ceased
Application number
PCT/EP2024/065296
Other languages
English (en)
Inventor
Rui ZOU
Qing Xue WANG
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.)
Signify Holding BV
Original Assignee
Signify Holding BV
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 Signify Holding BV filed Critical Signify Holding BV
Priority to CN202480038646.0A priority Critical patent/CN121286101A/zh
Priority to EP24730040.3A priority patent/EP4725270A1/fr
Publication of WO2024256212A1 publication Critical patent/WO2024256212A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology

Definitions

  • the present invention relates to the field of LED lighting, and in particular to a circuit used for powering the LED.
  • FIG. 1 shows a typical schematic for class A bulb.
  • L and N are the input interface to receive an input AC mains voltage.
  • Fl is a fuse.
  • Diodes DI to D4 form a rectifier bridge.
  • Capacitor Cl is a bulk/Vbus capacitor to smooth the power provided by the rectifier bridge.
  • Inductor LI, diode D5, and IC chip U1 form a buck converter.
  • the output of the buck converter is connected to a LED string of LED 1, LED2 and LED3, with an output capacitor C2 connected in parallel with the LED string.
  • the power supply terminal HV of the IC chip is connected to the positive output of the rectifier/ anode terminal of the capacitors C1/C2.
  • the highest voltage of the anode terminal of the capacitor C1/C2 reaches 325V.
  • the working current of the IC chip could be chosen as 400uA, and therefore the power consumption of the IC chip is 130mW. For a 4.3W class A bulb, there will be 3% efficiency loss, which is obviously needs to be reduced.
  • US2022240356A1 dislcoses a LED control device with a controller.
  • the controller is connected to a + voltage of a driving power via a power supply, and is connected to a - voltage of the driving power.
  • WO2011027299 discloses a relevant circuit.
  • the inventors finds that the circuit in fig. 2 has some side effect.
  • the IC chip works in standby, and the working current of the IC chip still flow/leak through the LED string and will make the LED string slightly bright/glow.
  • the glow may annoy user especially in the night, but also the leakage current through the LED string causes power loss on the LED string regardless of whether visible glow is generated or not. Thus it is needed to avoid the leakage current through the LED string.
  • This problem does not only relate to a driver IC that controls a switched mode power supply in the lighting circuit, but also applies for other controller integrated circuits such as MCU if other controller integrated circuits also tap the supply voltage via the LED: the operation of MCU in standby also produce a small current leakage through the LEDs to emit glow and cause power loss on the LEDs.
  • a basic idea of the present invention is to manipulate, in a non-light-emitting mode of the LED lighting circuit, the abovementioned circuit for the supply voltage in such a way that the supply voltage to the controller integrated circuit is decoupled from going through the LEDs.
  • a LED lighting circuit comprising a LED string comprising at least one LED; an input interface adapted to connect and receive an input power; an output interface connecting to the LED string and outputting an output power; a controller circuit adapted to control the LED lighting circuit, and comprising a supply terminal to receive a supply voltage; and a connection circuit connecting said supply terminal to a cathode of one LED in the LED string such that the supply voltage is retrieved in sequence of from the input interface, via an anode of the LED, the LED, the cathode of the LED and to the supply terminal characterized in that further comprising; a controlling interface to receive a command to instruct said LED lighting circuit to switch into a non-light-emitting mode; and a switching circuit adapted to manipulate said connection circuit so that the supply voltage is decoupled from going through the LED via the anode and cathode of the LED when in the nonlight-emitting mode.
  • connection circuit is manipulated so that the supply voltage is decoupled from going through the LED when in the non-light-emitting mode.
  • the LEDs would not glow and annoy the user.
  • the removal of glow also reduces the power loss on the LED in the non-light-emitting mode.
  • the switching circuit is adapted to cut off the supply connection.
  • the connection circuit is cut off thus prevent any current flowing through the LED string.
  • the supply terminal is adapted to receive a positive voltage.
  • said LED driving circuit further comprises a switchable second supply connection in parallel with said LED string, and the switching circuit is adapted to conduct the switchable second supply connection thereby bypassing the LED string in the non-light-emitting mode, and cut off said second switchable second supply connection otherwise.
  • said LED driving circuit further comprises a third supply connection electrically connecting the supply terminal and the input interface without passing through the LED string, and the switching circuit is adapted to enable said third supply connection and connect the supply terminal to the input interface thereby bypassing the connection circuit in the non-light-emitting mode, and to disable said third supply connection otherwise.
  • the supply voltage comes from a different location without passing through the LEDs thus prevents glow and power loss on the LEDs, meanwhile the controller circuit is still operable for providing standby functions such as fast wake up etc..
  • the switching circuit further comprises a voltage detector adapted to detect a voltage across the LED string, and the switching circuit is adapted to manipulate said connection circuit according to a detected voltage across the LED string.
  • the switching circuit can determine whether the LED string has been turned off via the voltage across the LED string by itself, without needing a dedicated signal from another controlling device such MCU.
  • the complexity of circuit is low.
  • the LED is any one between the middle and the last LED in the string starting in a direction of forward bias. Preferably it is the last LED because the power loss on the controller circuit would be less. If the controller integrated requires a higher supply voltage, the LED from which the supply voltage is tapped could also either be one in the last few LEDs, or the middle LED, and the power loss is also acceptable.
  • said input interface is adapted to connect to either a rectified AC mains voltage; or an AC -DC converted voltage.
  • the input power to the input interface can either be unconverted AC voltage or an already converted DC voltage.
  • said output interface comprises a positive terminal and a negative terminal
  • said LED string is connected to the positive terminal of the output interface via the anode of the LED string and to the negative terminal of the output interface via the cathode of the LED string
  • said positive terminal of the output interface is electrically connected to a positive terminal of the input interface, thereby the supply voltage is clamped lower than a voltage on the positive terminal of the input interface by the LED.
  • the supply voltage is the voltage on the input interface subtracted by the forward voltage of LEDs thus the supply voltage may be significantly lower than the voltage on the input interface, and the power loss on the controller circuit can be substantially reduced.
  • the LED lighting circuit further comprises a switched mode power supply between the input interface and the output interface
  • the controller circuit comprises a driver control IC adapted to control the switched mode power supply.
  • the controller circuit comprises a micro controller unit (MCU), a sensor module or a RF communication module.
  • MCU micro controller unit
  • sensor module a sensor module
  • RF communication module a RF communication module
  • said switched mode power supply comprises a buck converter wherein the LED string is connected to a positive terminal of the input interface and an inductor of the buck converter is connected to a negative terminal of the input interface.
  • the embodiment of the invention is suitable for buck converter topology. Please note that other type of converter may also be applicable.
  • a LED lighting device comprising the LED lighting circuit of the first aspect.
  • Figure 1 shows typical circuit schematic for class A bulb
  • Figure 2 shows an improved circuit schematic for class A bulb
  • Figure 3 shows a schematic of a LED lighting circuit according to an embodiment of the invention
  • Figure 4 shows a schematic of a LED lighting circuit according to another embodiment of the invention.
  • Figure 5 shows a schematic of a LED lighting circuit according to yet another embodiment of the invention.
  • FIG 3 to figure 5 shows several embodiments of the invention.
  • L and N are the input interface to receive an input AC mains voltage.
  • Fl is a fuse.
  • Diodes DI to D4 form a rectifier bridge.
  • Capacitor Cl is a bulk capacitor to smooth the voltage/power proved by the rectifier bridge.
  • Inductor LI, diode D5, and IC chip U1 form a buck converter.
  • the output of the buck converter is connected to a LED string of LED 1, LED2 and LED3, with an output capacitor C2 connected in parallel with the LED string.
  • the power supply terminal HV of the IC chip is connected to the cathode of the last LED LED3 in the LED string via a connection circuit 20.
  • the switching circuit in the embodiment in figure 3 comprises a switch QI and peripheral circuits including resistor R4, switch Q2, resistors R5, R6, and R3.
  • the switch QI is implemented by a NPN transistor, and the switch Q2 is implemented by a PNP transistor.
  • MCU When the user or the light control system commands the lamp in a non-light- emitting/OFF/standby state, MCU outputs a low level to cut OFF the transistor Q2 and the transistor QI, thus the connection circuit 20 is open, so as to prevent any current of the chip from flowing through the LED to make the LED emit light.
  • the IC chip U1 stops working,
  • the LED lighting circuit further comprises another supply connection circuit to provide the supply voltage to the controller integrated circuit in standby mode, without passing the supply voltage through the LEDs.
  • the LED lighting circuit comprises a switchable second supply connection 40 in parallel with said LED string LED1, LED2 and LED3, and the switching circuit QI is adapted to conduct the switchable second supply connection 40 thereby bypassing the LED string in the non-light-emitting mode, and cut off said second switchable second supply connection 40 otherwise.
  • the second supply connection 40 is connected to the positive output of the rectifier bridge and the supply terminal HV, in figure 4 it connects to the supply terminal HV via the connection circuit 20.
  • the voltage at both ends of the LED string, detected by the voltage detector R6 and R7 is high for example is higher than 200V.
  • the output voltage of the voltage detector is high and turns on the transistor Q2, and turns off the MOSFET QI, and the second supply connection 40 is cut off, and power supply current of the IC chip U1 flows into the supply terminal HV from the LED string through the original connection circuit 20.
  • the buck converter When the buck converter is commanded by the MCU into standby mode, its output power does not drive the LED but only maintain a voltage across the capacitor C2 smaller than the forward voltage of the LED, and the LED is in OFF state.
  • the voltage at both ends of the LED string drops to for example less than 170 V.
  • the output voltage of the voltage detector R6 and R7 is low, and the transistor Q2 is cut OFF.
  • the MOSFET QI is in ON state, and the second supply connection 40 becomes close/conductive, and power supply current of the IC chip flows into the IC from the resistor R5 and the MOSFET QI.
  • the LED string is substantially open thus would not conduct the supply current, and would not glow or generate power loss.
  • Fig. 5 shows an embodiment modified from the embodiment in fig. 4.
  • the voltage at both ends of the LED string, detected by the voltage detector R6 and R7 is high for example is higher than 200V.
  • the output voltage of the voltage detector R6 and R7 is high and turns off the MOSFET QI via a certain MOSFET driving circuit such as Q2 in fig. 4, and the third supply connection 50 is cut off, and power supply current of the IC chip U1 flows into the supply terminal HV from the LED string through the original connection circuit 20.
  • the buck converter When the buck converter is commanded by the MCU into standby mode, its output power does not drive the LED but only maintain a voltage across the capacitor C2 smaller than the forward voltage of the LED, and the LED is in OFF state.
  • the voltage at both ends of the LED string drops to for example less than 170 V.
  • the output voltage of the voltage detector is low and turn on the MOSFET QI, and the third supply connection 50 becomes close/conductive, and power supply current of the IC chip flows into the IC directly from the positive output of the rectifier bridge.
  • the LED string is substantially open thus would not conduct the supply current, and would not glow or generate power loss.
  • cool white LED channel and the warm white LED channel can also be replaced by or added with red, green and blue LED channels.

Landscapes

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

Abstract

L'invention concerne un circuit d'éclairage à DEL comprenant une chaîne de DEL (LED1, LED2, LED3) comprenant au moins une DEL (LED3) ; une interface d'entrée conçue pour connecter et recevoir une puissance d'entrée ; une interface de sortie connectée à la chaîne de DEL (LED1, LED2, LED3) et délivrant une puissance de sortie ; un circuit de commande (U1) conçu pour commander le circuit d'éclairage à DEL, et comprenant une borne d'alimentation (HV) pour recevoir une tension d'alimentation; et un circuit de connexion (20) connectant ladite borne d'alimentation à une cathode d'une DEL (LED3) dans la chaîne de DEL de telle sorte que la tension d'alimentation est récupérée en séquence à partir de l'interface d'entrée, par l'intermédiaire d'une anode de la DEL, de la DEL (LED3), de la cathode de la DEL et de la borne d'alimentation, caractérisé en ce qu'il comprend ; une interface de commande pour recevoir une commande pour ordonner audit circuit d'éclairage à DEL de commuter dans un mode non électroluminescent ; et un circuit de commutation conçu pour manipuler ledit circuit de connexion (20) de telle sorte que la tension d'alimentation est découplée de passer à travers la DEL (LED3) par l'intermédiaire de l'anode et de la cathode de la DEL lorsqu'il est dans le mode non électroluminescent. La perte de luminescence et de puissance sur la DEL dans le mode non électroluminescent sont empêchées.
PCT/EP2024/065296 2023-06-12 2024-06-04 Circuit d'éclairage à del et dispositif d'éclairage à del Ceased WO2024256212A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202480038646.0A CN121286101A (zh) 2023-06-12 2024-06-04 Led照明电路和led照明设备
EP24730040.3A EP4725270A1 (fr) 2023-06-12 2024-06-04 Circuit d'éclairage à del et dispositif d'éclairage à del

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CNPCT/CN2023/099604 2023-06-12
CN2023099604 2023-06-12
EP23181959.0 2023-06-28
EP23181959 2023-06-28

Publications (1)

Publication Number Publication Date
WO2024256212A1 true WO2024256212A1 (fr) 2024-12-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2024/065296 Ceased WO2024256212A1 (fr) 2023-06-12 2024-06-04 Circuit d'éclairage à del et dispositif d'éclairage à del

Country Status (3)

Country Link
EP (1) EP4725270A1 (fr)
CN (1) CN121286101A (fr)
WO (1) WO2024256212A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009013676A2 (fr) * 2007-07-23 2009-01-29 Nxp B.V. Disposition de del avec circuit de dérivation
WO2011027299A2 (fr) 2009-09-04 2011-03-10 Koninklijke Philips Electronics N.V. Circuit de diodes électroluminescentes
US20190268984A1 (en) * 2018-02-27 2019-08-29 Lumileds Llc Tapped single-stage buck converter led driver
US20220240356A1 (en) 2021-01-25 2022-07-28 Samsung Electronics Co., Ltd. Led control device and lighting device including the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009013676A2 (fr) * 2007-07-23 2009-01-29 Nxp B.V. Disposition de del avec circuit de dérivation
WO2011027299A2 (fr) 2009-09-04 2011-03-10 Koninklijke Philips Electronics N.V. Circuit de diodes électroluminescentes
US20190268984A1 (en) * 2018-02-27 2019-08-29 Lumileds Llc Tapped single-stage buck converter led driver
US20220240356A1 (en) 2021-01-25 2022-07-28 Samsung Electronics Co., Ltd. Led control device and lighting device including the same

Also Published As

Publication number Publication date
EP4725270A1 (fr) 2026-04-15
CN121286101A (zh) 2026-01-06

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