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
  • H05B45/34—Voltage stabilisation; Maintaining constant voltage
• • 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
  • H05B45/357—Driver circuits specially adapted for retrofit LED light sources
• • 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
  • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
  • H05B47/10—Controlling the light source
  • H05B47/105—Controlling the light source in response to determined parameters
  • H05B47/11—Controlling the light source in response to determined parameters by determining the brightness or colour temperature of ambient 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
  • 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]
  • H05B45/30—Driver circuits
  • H05B45/37—Converter circuits
  • H05B45/3725—Switched mode power supply [SMPS]
  • H05B45/38—Switched mode power supply [SMPS] using boost 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]
  • H05B45/30—Driver circuits
  • H05B45/37—Converter circuits
  • H05B45/3725—Switched mode power supply [SMPS]
  • H05B45/385—Switched mode power supply [SMPS] using flyback 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
  • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
  • H05B47/10—Controlling the light source
  • H05B47/175—Controlling the light source by remote control
  • H05B47/19—Controlling the light source by remote control via wireless transmission

Definitions

• a power supply is needed which generates multiple outputs.
• An auxiliary supply is needed, in addition to the main supply for the lighting load, for supplying master control units, logic circuits, gate drivers sensors and/or communications modules etc.
• a standalone auxiliary power supply is widely adopted in an LED driver. There is then a standby power supply separate to the main LED driver, which functions as the power supply for the lighting load.
• LED driver power is dimmed down, the efficiency is very important in order to provide energy savings.
• the LED driver must be designed according to the maximum power requirements, so large current rating components are used in the design which means the high -efficiency region is at the average to high power/load and the efficiency of LED driver at a light load is low.
• the typical efficiency is as shown in Figure 1, which plots the efficiency (E, y-axis) versus the loading as a percentage of the rated load. There is a particular efficiency issue at low load conditions. There is therefore a need to enable improved efficiency in a driver for a LED light source and which enables additional modules to be provided with a low standby power requirement.
• WO2015128388A1 discloses a two-driver architecture wherein a switched mode power supply’s input current can be regulated according to whether a capacitor of a linear driver is being charged at the peak of the mains, so as to provide good power factor and less flicker, meanwhile obtain a homogenous light output.
• WO2015185570A1 discloses an emergency lamp with a LED driver to power the LED, and a DC-DC converter to power the LED from a battery when there is emergency, power cut on the supply.
• US9826583B1 discloses an auxiliary power supply, in an LED driver, that powers an external controller which is for controlling a controller in the LED driver.
• auxiliary driver to deliver power to a LED lighting load, instead of a main LED driver, when the LED power demand is sufficiently low that it can be met by the auxiliary driver.
• the auxiliary driver is generally still a low power driver when supplied by the AC mains and is originally only intended for auxiliary modules, such as sensors and communications circuits, and has a power delivery capability which is lower than the peak power demand of the LED lighting load.
• a driver arrangement for a LED lighting device with a LED light source and at least one additional auxiliary module comprising:
• a main power output for providing power to the LED light source
• a main LED driver having a main power conversion circuit, the main LED driver connected to the main power output
• an auxiliary power output for providing power to the at least one additional auxiliary module
• controller is adapted to
• auxiliary driver to provide power to the LED light source when the output power of the LED light source is set, in accordance with the dimming command, lower than a threshold value.
• the controller for example controls the delivery of power from the auxiliary driver to the auxiliary power output or to both the main power output and the auxiliary power output.
• This driver arrangement has separate drivers for an LED lighting device and for one or more auxiliary modules. In this way, each driver can be optimized for the load it is required to drive. This means that the device may be more efficient in a low power lighting mode, by using a driver suited for such low power operation.
• the output of the auxiliary driver is able to be used to power the LED light source. This may for example be appropriate when the power demand of the LED light source is low, for example during periods of deep dimming. By using the auxiliary driver for this time, the overall efficiency of the driver arrangement may be improved.
• the auxiliary driver may be used to deliver the required power more efficiently that the main LED driver.
• the command connection is different from the AC mains
• the main LED driver and the auxiliary driver are both adapted to power the LED from the AC mains
• the rate maximum power of the auxiliary driver is lower than the rate maximum power of the main LED driver
• the auxiliary driver has a high efficiency than that of the main LED driver at the set output power lower than the threshold value.
• the command connection is a wireless connection.
• the controller is preferably adapted to control the delivery of power in dependence on the power demand of the LED light source and of the at least one additional auxiliary module.
• auxiliary driver either for the auxiliary module (or modules) or additionally for the LED light source thus takes account of both power demands. If both can be met by the auxiliary driver, then it will be used as the sole power supply. If both cannot be met by the auxiliary driver, then the auxiliary driver should not be overloaded and preferably the two drivers will both be used.
• the at least one additional auxiliary module may comprise: an RF communication device; or
• the selective control of power delivery enables efficiency improvements to be obtained, by avoiding operating a high power driver at very low power demand levels.
• a power delivery to the LED light source from the auxiliary driver may be sensed so that a power delivery to the LED light source is then controlled from the main LED driver accordingly.
• Selectively controlling the delivery of power is for example in dependence on the power demand of the LED light source and of the at least one additional auxiliary module.
• Fig. 5 shows one example of the control method implemented by the controller
• Figure 2 shows a driver arrangement 10 for a LED lighting device 12 with a LED light source 14 and at least one additional auxiliary module 16.
• the lighting device is defined as the overall system, including the light source, the driver arrangement and the auxiliary modules.
• the driver arrangement 10 has a main power output 18 for providing power to the LED light source 14.
• a main LED driver 20 is connected to the main power output 18. It comprises a switch mode power supply, having a main power conversion circuit.
• the auxiliary power supply can then be used to supply the LED light source. This results in a more efficient operation than if the main LED driver is used.
• the load of the auxiliary power supply is typically variable over time (sensors are for example activated periodically or communications are intermittent) so the auxiliary driver is not always operated at a full load condition, and part of the load capacity is often available for use in supplying the LED light source.
• the controller 26 is shown as two separate control units, one 26a for the main driver power supply and one 26b for the auxiliary driver power supply.
• Figure 4 shows the auxiliary driver 24 in more detail.
• a first current sense resistor Rpk is provided for measuring the peak primary side current Ipk in the boost charging phase
• a second current sense resistor Rs' is provided for measuring the output current to the LED light source.
• the second current sense resistor can be represented schematically in Figure 3 as the sensor 52.
• the boost charging phase both switches Ql and Q2 are on, the power is accumulated in the main inductor 42; in the freewheeling phase, the main inductor 42 discharges to the buffer capacitor C B , in turn to the LEDs, via the diode D2, and also the secondary inductor 44 discharges via the diode D3 and to the additional modules.
• FIG. 5 shows one example of the control method implemented by the controllers 26a, 26b.
• step 60 the power demand of the LED light source is obtained.
• This in particular relates to the dimming setting.
• This dimming setting is for example communicated to the controller 26a over a wireless connection (and the wireless communications circuitry is one of the auxiliary modules, powered by the auxiliary driver).
• step 62 it is determined if the LED load is greater than 10W (for the example of a 100W main driver and 10W auxiliary driver). Thus, the current setting is at a level higher than 10% of the maximum. If the LED load demand is greater than 10W, then the main driver is used to supply the LED load in step 64.
• the main driver and the auxiliary driver operate separately. This can be achieved by tuning the output of the auxiliary driver to be slightly lower than the LED string voltage drop, so that the auxiliary driver will not provide power to LED load.
• step 66 it is determined if the total load demand, namely the LED load demand and the power demand of the auxiliary modules, is greater than 10W.
• the auxiliary load demand can be obtained by detecting the primary winding current and current sense resistor voltage for the sense resistor Rpk, in particular when no power is being delivered to the LED load.
• the controller can request the additional modules to inform its power demand.
• Ipk is the peak primary side current
• fs is the switching frequency
• Lk is the inductance
• the auxiliary power is thus given by subtracting the load contribution of the LED light source as provided by the auxiliary driver:
• auxiliary load information can be directly given by the auxiliary load itself which include a microcontroller.
• the controller 26b can then make a judgement of whether the needed LED driver load and auxiliary load is larger than the set threshold (10W in this example).
• the auxiliary driver operates at full rated power (i.e. it operates at 10W).
• This 10W comprises the auxiliary power (e.g. the power P S B) and the balance (T 0-P S B) is provided by the auxiliary driver to the LED light source. The remaining power is delivered by the main driver. This is step 68.
• the additional module can regulate its input power as PSB, SO that the remaining power ( 10-Psis) is automatically supplied to LED light source by setting the output voltage slightly higher than the LED string voltage.
• the main driver and the auxiliary driver then supply the LED load in parallel.
• the sensing resistor Rs is placed before the current return path (ground) to the auxiliary driver, the total LED current from both the main LED driver and the auxiliary driver is sensed by current sensing resistor Rs.
• the closed loop control then maintains the main LED driver at a setting to provide the required additional current output.
• the main driver will provide power corresponding to the dimming level power level minus ( 10-Psis) .
• the peak current of the primary winding is set to:
• step 70 If the total demand is not greater than 10W, then the main driver can be turned off and the auxiliary driver operates this total demand level, providing both the auxiliary power requirement and the LED load requirement. This is step 70.
• Figure 6 shows the efficiency improvement achieved by adopting the architecture explained above.
• the low power operation shows improved efficiency, since the auxiliary driver is used by default for lower power operation.
• the voltage Vspk on the sensing resistor Rpk is compared with a reference voltage VIpk which corresponds to the peak primary current in order to provide the peak (10W) output power.
• a first amplifier circuit 90 generates an output signal based on a comparison between VIpk and Vspk. This means if the real current at the charging phase is less than a peak charging current corresponding to 10W, the duty cycle of the driver will be increased to increase the real current.
• a second amplifier circuit 90 generates an output signal based on a comparison between the auxiliary driver output voltage Vo (shown in Figure 4) and a desired output voltage setting Vo ref. This means if the real output voltage Vo is less than the voltage reference, the duty cycle of the driver will be increased to increase the real output voltage.
• a summing unit 94 performs a sum operation.
• the output of the unit 94 is provided to a comparator 96 whose other input is a saw tooth signal, thereby generating a PWM gate control signal for the auxiliary driver. More specifically, if the value Vo is much less than Vo ref, or the real current is much less than the current corresponding to 10W operation, the amplifier circuit will output a high value to the comparator 96, the high value is compared with the saw tooth wave giving rise to a high duty cycle. The comparator thus outputs longer high state period, thereby to increase the on time of the switches Ql and Q2 to increase power charging, thereby increasing the power of the driver in order to increase the value of Vo or the real current. An opposite function takes place when the value Vo is high or the current is high, leading to a low duty cycle and reduced on time of the switches Ql and Q2.
• the main LED driver will be turned off and the auxiliary driver will provide the combined power.
• the auxiliary driver only needs to obtain the dimming command of LED driver and detect the additional module’s load (or receive load information from a load controller), and it can adjust the on time of the auxiliary driver switch to make sure the total output power matches the needed LED power and auxiliary load based on closed loop control.
• FIG. 10 shows an alternative implementation of the auxiliary driver circuit 24.
• the auxiliary modules are supplied by a power output circuit with a first secondary winding 44 and the LED lighting device is supplied by a further power output circuit with a further secondary winding 102. In this way, an isolated output is provided to the LED lighting device as well as to the auxiliary circuits.
• the controller 26b is powered by supply voltage Vcc generated by a primary side power supply circuit 108.

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

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• 2019
  • 2019-04-17 CN CN201980027869.6A patent/CN112042278B/zh active Active
  • 2019-04-17 EP EP19717332.1A patent/EP3785491B1/en active Active
  • 2019-04-17 JP JP2020558919A patent/JP7348205B2/ja active Active
  • 2019-04-17 WO PCT/EP2019/059963 patent/WO2019206771A1/en not_active Ceased
  • 2019-04-17 ES ES19717332T patent/ES3034495T3/es active Active
  • 2019-04-17 US US17/047,633 patent/US11457516B2/en active Active

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