JP4956409B2 - LED lighting fixtures - Google Patents

Description

  The present invention relates to an LED lighting apparatus that turns on a light source by supplying DC power to the light source composed of a light emitting diode.

  In recent years, lighting fixtures (hereinafter referred to as LED lighting fixtures) using light-emitting diodes (LEDs) as light sources instead of fluorescent lamps have been provided. LED lighting fixtures have the advantage of being able to save power and prolong life compared to lighting fixtures that use fluorescent lamps or the like as light sources. A general LED lighting apparatus is used by being connected to an AC supply line wired to a building, and receives AC power supplied from an AC power source such as a commercial power source via the AC supply line. In response, a light source composed of a light emitting diode is turned on.

  This type of LED lighting apparatus has an AC / DC conversion circuit that converts an AC power source into a DC power source, and adjusts the converted DC power to an appropriate magnitude so that the light source emits light. It is configured. Here, a switching power supply is often used to generate DC power suitable for lighting of the light source using the DC power after rectification.

  As a small-sized and high-efficiency switching power source applicable to this type of LED lighting apparatus, a complex resonance type series converter circuit is known (see, for example, Patent Document 1). FIG. 6 shows a main circuit configuration according to the prior art, and FIG. 7 shows waveforms of main parts in the circuit configuration of FIG.

  The LED lighting apparatus 1 of FIG. 6 has a diode bridge type full wave via a power switch SW0 and an inrush current limiting resistor R1 between a pair of AC input terminals In1 ′ and IN2 ′ connected to the AC supply line Wac. A rectifier DB is connected, and a smoothing capacitor C0 that forms the AC / DC conversion circuit 12 together with the full-wave rectifier DB is connected between the output terminals of the full-wave rectifier DB. Thus, when the power switch SW0 is turned on, a DC voltage is generated across the smoothing capacitor C0.

  A series circuit of first and second switching elements Q1, Q2 made of a power MOSFET is connected between both ends of the smoothing capacitor C0. A series resonance circuit of the inductor L, the primary winding L10 of the output transformer T1, and the capacitor C1 is formed between the connection point of the switching elements Q1 and Q2 and one end of the smoothing capacitor C0. A capacitor C2 is connected in parallel with one of the two switching elements Q1 and Q2 (in FIG. 6, one example of the smoothing capacitor C0 is connected to the low voltage side, and the capacitor C2 is connected to the second switching element Q2 in parallel. Is shown). Further, diodes D1 and D2 are connected in antiparallel to switching elements Q1 and Q2, respectively (generally also used as a MOSFET body diode).

  Further, an intermediate tap is provided in the secondary winding of the output transformer T1 and divided into two (L21, L22), and a full-wave rectifier circuit is formed by diodes D3, D4 that rectify their outputs, and the cathodes of the diodes D3, D4 And the smoothing capacitor C3 and the light source 2 are connected between the intermediate tap and the intermediate tap. The switching elements Q1 and Q2 are alternately turned on and off at a frequency set in advance by taking into account the complex resonance condition by the control unit 10 shown in the block. Therefore, the control unit 10 has a high-frequency oscillation function, a function of alternately driving the two switching elements Q1 and Q2, and a function of setting a dead time period for turning off the two switching elements Q1 and Q2. A feed-forward and feedback control function for controlling the input / output voltage, current, and power, and an output variable function are provided.

In FIG. 7, V _g1 and V _g2 indicate drive signals for the switching elements Q1 and Q2 set in advance by the control unit 10, and the drive signals are alternately turned on and off, and a dead time period during which both are turned off Is set. V _Q1 and V _Q2 and I _Q1 and I _Q2 indicate the drain-source voltage and drain current of the switching elements Q1 and Q2, respectively. Here, when the drive signal V _g1 is High, the drain current I _Q1 flows through the switching element Q1, and when it is Low, the voltage V _Q1 substantially equal to the voltage across the smoothing capacitor C0 is applied to the switching element Q1 (switching). The same applies to the element Q2.) In the dead time period, the drain-source voltages V _Q1 and V _Q2 have rising and falling waveforms with an arbitrary slope due to the effect of the capacitor C2, the inductor L, and the excitation inductance of the output transformer T1.

Further, the drain currents I _Q1 and I _Q2 have a series resonance current waveform set by the inductor L and the capacitor C1, and these combined currents are generated between the inductor L, the primary winding L10 of the output transformer T1, and the capacitor C1. This is the current of the series resonant circuit. V _C1 represents a voltage waveform of the capacitor C1, and has a waveform delayed in phase from the current of the series resonance circuit. I _D3 and I _D4 indicate current waveforms of the output rectifier diodes D3 and D4. The relationship between the drive frequency (switching frequency) of the switching elements Q1 and Q2 and the series resonance frequency of the inductor L and the capacitor C1 is “ By setting to satisfy the condition of “resonance frequency> driving frequency”, it is possible to set so that the other current starts flowing after one of the currents of the diodes D3 and D4 finishes flowing, and both diode currents do not flow. During the period, power is not transmitted to the output side. That is, during the period in which the currents of the diodes D3 and D4 do not flow, the secondary side of the output transformer T1 is considered to be unloaded, and the primary side exciting inductance of the transformer T is inserted in series into the primary side series resonance circuit. As a result of the switching of the series resonance condition, inflection points are also found in the waveforms of the drain currents I _Q1 and I _Q2 .

In such a complex resonance type series converter, it is possible to set conditions such that ZVS (zero voltage switching), that is, a current starts to flow through the switching elements Q1 and Q2 after the applied voltage of the switching elements Q1 and Q2 decreases. Since the switching loss is extremely small and the recovery loss of the diodes D3 and D4 can be avoided, high frequency can be achieved with high efficiency. In addition, the voltage / current waveform at the time of switching is stable and the ringing of the diodes D3 and D4 can be suppressed, so that the noise is also excellent.
Japanese Patent No. 2734296

  By the way, since the LED lighting fixture 1 mentioned above is connected to AC power supply AC via AC supply line Wac, the AC / DC conversion circuit 12 which converts AC power supply AC into DC power supply is an essential structure. However, when the LED lighting apparatus 1 is downsized, there is a problem that the full-wave rectifier DB and the smoothing capacitor C0 constituting the AC / DC conversion circuit 12 hinder downsizing.

  Further, the above-described conventional technique is a so-called separately excited switching power source 11 that sets a frequency with an oscillator in advance and drives the two switching elements Q1 and Q2, and requires a level shifter to the switching element Q1 on the high potential side. Since there is a limit to increasing the switching frequency of the switching elements Q1 and Q2 from the viewpoint of frequency followability and loss, it is difficult to reduce the size of the output transformer T1, which hinders the overall size reduction of the LED lighting apparatus 1. .

  This invention is made | formed in view of the said reason, Comprising: It aims at providing the LED lighting fixture which can be reduced in size compared with the conventional structure.

  The invention of claim 1 is an LED lighting apparatus used in a DC power distribution system that supplies DC power output from an AC / DC converter that converts AC power to DC power to a DC device via a DC supply line wired to a building. A light source composed of a light emitting diode, a pair of DC input terminals connected to a DC supply line, and first and second switching elements connected in series between the pair of DC input terminals and alternately controlled on and off. A series resonant circuit including a series circuit of an inductor, a primary winding of the output transformer, and a capacitor connected in parallel with one of the first and second switching elements, and a first secondary of the output transformer A rectifier that rectifies the voltage induced in the winding, a smoothing capacitor that smoothes the output of the rectifier and applies it to the light source, and is magnetically coupled to the primary winding of the output transformer. The first and second auxiliary windings that turn on the first and second switching elements by the voltage induced between both ends, and the voltages induced in the first and second auxiliary windings, respectively. And a first control circuit for turning off the first switching element and the second switching element on the basis of the switch body. A peak hold circuit for peak-holding an induced voltage generated in the winding, and a comparator that turns on the switch element when the induced voltage is lowered by a predetermined level or more from the hold voltage by the peak hold circuit.

  According to this configuration, the pair of DC input terminals of the LED lighting fixture is connected to the output of the AC / DC converter via the DC supply line, and thus the DC lighting is supplied to the LED lighting fixture via the DC supply line. Will be. Therefore, the LED lighting apparatus does not require an AC / DC conversion circuit that converts AC power into DC power, and the LED lighting apparatus can be reduced in size by the full-wave rectifier and the smoothing capacitor that constitute the AC / DC conversion circuit. There is an advantage of becoming. Furthermore, according to the above configuration, in the switching power supply including the voltage feedback type self-excited complex resonance series converter that uses the induced voltage of the first and second auxiliary windings to turn on each switching element, each control circuit includes: A switching element that turns off the switching element when the on-state is turned on, a peak hold circuit that holds the induced voltage generated in each auxiliary winding in a peak, and a switching element when the induced voltage drops by a predetermined level or more from the hold voltage by the peak holding circuit Of the first and second auxiliary windings to detect the voltage drop of one of the first and second auxiliary windings, and drive the off side of the first and second switching elements. At the same time, the other voltage rise turns on the off side of the first and second switching elements. In this way, in the voltage feedback type self-excited complex resonance series converter, appropriate switching conditions (ZVS operation) can be realized with a simple configuration, while maintaining the low loss and low noise, which are the original features, compared to the other excitation type. Therefore, the circuit can be greatly simplified and the cost can be reduced. In addition, the switching frequency can be increased and the LED lighting apparatus can be reduced in size by downsizing the output transformer.

  According to a second aspect of the invention, in the first aspect of the invention, the switching frequency of the first and second switching elements is 500 kHz or more.

  According to this configuration, it is possible to reduce the size of the output transformer by setting the switching frequency to 500 kHz or higher, which is difficult with the conventional separately excited type.

  According to a third aspect of the invention, in the first or second aspect of the invention, the instrument body is charged with a voltage induced in a second secondary winding provided on the secondary side of the output transformer. A secondary battery, a power failure detection means for detecting a stop of power supply from the direct current supply line to the direct current input terminal, and a secondary battery that receives an input to the direct current input terminal when a power supply stop is detected by the power failure detection means Input switching means for switching to.

  According to this configuration, when the stop of power supply from the DC supply line to the DC input terminal is detected, the input to the DC input terminal is switched to the secondary battery. For example, it can be applied to emergency lights and guide lights.

  The invention of claim 4 is the invention of claim 3, comprising a portable container that constitutes the outline of the instrument body, the container holding a contact connected to the DC input end, The contact is detachably attached to a DC outlet having a contact receiver connected to the DC supply line so as to be in contact with the contact receiver.

  According to this configuration, the light source can be turned on using the secondary battery as a power source even when the portable device of the LED lighting device is removed from the direct current outlet, and the LED lighting device can be turned on as a portable light such as a flashlight. Can be used as an instrument.

  The present invention has an effect that the LED lighting apparatus can be downsized as compared with the conventional configuration.

  As shown in FIG. 2, the LED light-emitting device described in each of the following embodiments uses an AC power source AC such as a commercial power source as a DC power source by an AC / DC converter 112 disposed in a distribution board 110 such as a house. It is used in a DC distribution system that converts and distributes DC power from the distribution board 110 to a DC outlet such as a DC outlet 131 that is installed in each room and has a pair of positive and negative power feeding units.

  Here, the DC power distribution system will be briefly described below with reference to FIG.

  In the following description, a description will be given assuming a detached house as a building to which the DC power distribution system is applied, but this does not preclude the application of the technical concept of the DC power distribution system to an apartment house. As shown in FIG. 2, the house H is provided with a DC power supply unit 101 that outputs DC power and a DC device 102 as a load driven by the DC power, and an output end of the DC power supply unit 101. DC power is supplied to the DC device 102 through the DC supply line Wdc connected to the. A current flowing through the DC supply line Wdc is monitored between the DC power supply unit 101 and the DC device 102. When an abnormality is detected, power is supplied from the DC power supply unit 101 to the DC device 102 on the DC power supply line Wdc. A DC breaker 114 is provided for limiting or blocking the current.

  The DC supply line Wdc is used as both a DC power supply path and a communication path, and is connected to the DC supply line Wdc by superimposing a communication signal for transmitting data on a DC voltage using a high-frequency carrier wave. Enables communication between devices. This technique is similar to a power line carrier technique in which a communication signal is superimposed on an AC voltage in a power line that supplies AC power.

  The DC supply line Wdc is connected to the home server 116 via the DC power supply unit 101. The in-home server 116 is a main device for constructing a home communication network (hereinafter referred to as “home network”), and communicates with a subsystem constructed by the DC device 102 in the home network.

  In the example shown in the drawing, as an subsystem, an illumination system comprising an information equipment system K101 comprising an information-system DC device 102 such as a personal computer, a wireless access point, a router, and an IP telephone, and an illumination system DC equipment 102 such as a lighting fixture. K102 and K105, an intercom system K103 including a DC device 102 that handles visitor correspondence and intruder monitoring, and a residential alarm system K104 including a warning DC device 102 such as a fire detector. Each subsystem constitutes a self-supporting distributed system, and can operate even with the subsystem alone.

  The above-described DC breaker 114 is provided in association with a subsystem. In the illustrated example, four DCs are associated with the information equipment system K101, the lighting system K102 and the intercom system K103, the house alarm system K104, and the lighting system K105. A breaker 114 is provided. When a plurality of subsystems are associated with one DC breaker 114, a connection box 121 for dividing the system of the DC supply line Wdc is provided for each subsystem. In the illustrated example, a connection box 121 is provided between the illumination system K102 and the intercom system K103.

  As the information equipment system K101, there is provided an information equipment system K101 composed of a DC equipment 102 connected to a DC outlet 131 arranged in advance in the house H (constructed when the house H is constructed) in the form of a wall outlet or a floor outlet.

  The lighting systems K102 and K105 include a lighting system K102 composed of a lighting device (DC device 102) arranged in advance in the house H and a lighting device (DC device 102) connected to a hook ceiling 132 arranged in advance on the ceiling. An illumination system K105 is provided. At the time of interior construction of the house H, the contractor attaches the lighting fixture to the hook ceiling 132, or the householder himself attaches the lighting fixture.

  In addition to using an infrared remote control device, a control instruction for the lighting apparatus that is the DC device 102 constituting the lighting system K102 can be given using a communication signal from the switch 141 connected to the DC supply line Wdc. That is, the switch 141 has a communication function together with the DC device 102. In addition, a control instruction may be given by a communication signal from another DC device 102 in the home network or the home server 116 regardless of the operation of the switch 141. The instructions to the lighting fixture include lighting, extinguishing, dimming, and blinking lighting.

  Since any DC device 102 can be connected to the DC outlet 131 and the hooking ceiling 132 described above and DC power is output to the connected DC device 102, the DC outlet 131 and the hooking ceiling 132 are distinguished below. When it is not necessary, it is called “DC outlet”.

  These DC outlets are provided with plug-in connection ports (power feeding portions) into which contacts (not shown) provided directly on the DC device 102 or contacts (not shown) provided via connecting wires are inserted. It has a structure in which a contact receiver that opens to the body and directly contacts the contact inserted into the connection port is held by the container. That is, the direct current outlet supplies power in a contact manner. When the DC device 102 connected to the DC outlet has a communication function, a communication signal can be transmitted through the DC supply line Wdc. A communication function is provided not only in the DC device 102 but also in the DC outlet.

  The home server 116 not only is connected to the home network, but also has a connection port connected to the wide area network NT that constructs the Internet. When the in-home server 116 is connected to the wide area network NT, it is possible to receive services from the center server 200 that is a computer server connected to the wide area network NT.

  The service provided by the center server 200 includes a service that enables monitoring and control of equipment (including mainly the DC equipment 102 but also other equipment having a communication function) connected to the home network through the wide area network NT. is there. This service makes it possible to monitor and control devices connected to the home network using a communication terminal (not shown) having a browser function such as a personal computer, Internet TV, or mobile phone.

  The in-home server 116 has both functions of communication with the center server 200 connected to the wide area network NT and communication with equipment connected to the home network, and identification information about equipment in the home network ( Here, it is assumed that an IP address is used).

  The home server 116 enables monitoring and control of home devices through the center server 200 from a communication terminal connected to the wide area network NT by using a communication function with the center server 200. The center server 200 mediates between home devices and communication terminals on the wide area network NT.

  When monitoring and controlling home devices from a communication terminal, monitoring and control requests are stored in the center server 200, and the home device periodically performs one-way polling communication to monitor from the communication terminal. And receive control requests. With this operation, it is possible to monitor and control devices in the house from the communication terminal.

  Further, when an event that should be notified to the communication terminal, such as a fire detection, occurs in the home device, the home device notifies the center server 200, and the center server 200 notifies the communication terminal by e-mail.

  An important function among the communication functions with the home network in the home server 116 is the detection and management of the devices constituting the home network. The home server 116 automatically detects devices connected to the home network by applying UPnP (Universal Plug and Play). The home server 116 includes a display device 117 having a browser function, and displays a list of detected devices on the display device 117. The display device 117 has a configuration with a touch panel type or an operation unit, and can perform an operation of selecting desired contents from options displayed on the screen of the display device 117. Therefore, the user (contractor or householder) of the home server 116 can monitor or control the device on the screen of the display device 117. The display device 117 may be provided separately from the home server 116.

  The in-home server 116 manages information related to device connection, and grasps the type, function, and address of the device connected to the home network. Accordingly, the devices in the home network can be operated in conjunction with each other. Information on the connection of the device is automatically detected as described above. In order to operate the device in an interlocking manner, the device itself is automatically associated with the attribute held by the device itself, and the home server 116 is configured as a personal computer. It is also possible to connect various information terminals and use the browser function of the information terminals to associate devices.

  Each device holds the relationship of the interlocking operation of the devices. Therefore, the device can operate in an interlocked manner without passing through the home server 116. By associating the linked operations for each device, for example, by operating a switch that is a device, it is possible to turn on or off the lighting fixture that is the device. In many cases, the association of the interlocking operations is performed within the subsystem, but the association beyond the subsystem is also possible.

  By the way, the DC power supply unit 101 basically generates DC power by power conversion of an AC power supply AC supplied from outside the house like a commercial power supply. In the configuration shown in the figure, the AC power source AC is input to an AC / DC converter 112 including a switching power source through a main circuit breaker 111 attached to the distribution board 110 as an internal unit. The DC power output from the AC / DC converter 112 is connected to each DC breaker 114 through the cooperative control unit 113.

  The DC power supply unit 101 is provided with a secondary battery 162 in preparation for a period in which power is not supplied from the AC power supply AC (for example, a power failure period of the commercial power supply AC). It is also possible to use a solar cell 161 or a fuel cell 163 that generates DC power. The solar battery 161, the secondary battery 162, and the fuel battery 163 are distributed power supplies with respect to the main power supply including the AC / DC converter 112 that generates DC power from the AC power supply AC. In the illustrated example, the solar cell 161, the secondary battery 162, and the fuel cell 163 include a circuit unit that controls the output voltage, and the secondary battery 162 includes a circuit unit that controls charging as well as discharging.

  Of the distributed power sources, the solar cell 161 and the fuel cell 163 are not necessarily provided, but the secondary battery 162 is preferably provided. The secondary battery 162 is charged in a timely manner by a main power source or other distributed power source, and the secondary battery 162 is discharged not only in a period in which power is not supplied from the AC power source AC but also in a timely manner as necessary. The coordination control unit 113 performs charge / discharge of the secondary battery 162 and coordination between the main power source and the distributed power source. That is, the cooperative control unit 113 functions as a DC power control unit that controls the distribution of power from the main power source and the distributed power source constituting the DC power supply unit 101 to the DC device 102. Note that a configuration may be adopted in which the outputs of the solar cell 161, the secondary battery 162, and the fuel cell 163 are converted into AC power and used as input power of the AC / DC converter 112.

  Since the driving voltage of the DC device 102 is selected from a plurality of types of voltages depending on the device, a DC / DC converter is provided in the cooperative control unit 113 to convert the DC voltage obtained from the main power source and the distributed power source into a necessary voltage. Is desirable. Normally, one type of voltage is supplied to one subsystem (or DC device 102 connected to one DC breaker 114), but three or more wires are used for one subsystem. A plurality of types of voltages may be supplied. Alternatively, it is possible to adopt a configuration in which the DC supply line Wdc is of a two-wire type and the voltage applied between the lines is changed with time. The DC / DC converter may be provided in a plurality of dispersed manners like the DC breaker.

  In the above configuration example, only one AC / DC converter 112 is illustrated, but a plurality of AC / DC converters 112 can be arranged in parallel, and when a plurality of AC / DC converters 112 are provided. It is desirable to increase or decrease the number of AC / DC converters 112 that are operated according to the magnitude of the load.

  The AC / DC converter 112, the cooperative control unit 113, the DC breaker 114, the solar cell 161, the secondary battery 162, and the fuel cell 163 described above are provided with a communication function, and include a main power source, a distributed power source, and a DC device 102. It is possible to perform cooperative operations that deal with the load status. The communication signal used for this communication is transmitted in the form of being superimposed on the DC voltage in the same manner as the communication signal used for the DC device 2.

  In the above example, the AC / DC converter 112 is arranged in the distribution board 110 in order to convert the AC power output from the main breaker 111 into DC power by the AC / DC converter 112. On the output side, a branch breaker (not shown) provided in the distribution board 110 branches the AC supply line into a plurality of systems, and an AC / DC converter is provided on the AC supply line of each system to convert it into DC power for each system. You may employ | adopt the structure to do.

  In this case, since the DC power supply unit 101 can be provided for each floor or room of the house H, the DC power supply unit 101 can be managed for each system, and the DC device 102 that uses DC power and Since the distance of the DC supply line Wdc between the two is reduced, the power loss due to the voltage drop in the DC supply line Wdc can be reduced. Also, the main breaker 111 and the branch breaker are housed in the distribution board 110, and the AC / DC converter 112, the cooperative control unit 113, the DC breaker 114, and the home server 116 are housed in a separate board from the distribution board 110. Also good.

  Below, although the example which applied this invention to the LED lighting fixture (DC apparatus 102) which comprises the illumination system K102 in the DC distribution system mentioned above is demonstrated, this invention is applied to LED lighting fixtures other than this kind of LED lighting fixture. Can also be applied. Here, the magnitude of the DC voltage applied to the DC device 102 from the DC outlet is set to be lower (for example, 24V, 50V, etc.) than the AC commercial power supply.

(Embodiment 1)
The LED lighting apparatus 1 (DC device 102) of this embodiment is connected to the output of the AC / DC converter 112 provided in the distribution board 110 via a pair of DC supply lines Wdc as shown in FIG. In response to the supply of DC power from the AC / DC converter 112, the light source 2 composed of a light emitting diode (LED) is turned on. Although the illumination system K102 includes a plurality of LED lighting fixtures, only one LED lighting fixture 1 is illustrated in FIG. 1, and illustration of other LED lighting fixtures is omitted. Further, in FIG. 1, illustrations of devices other than the AC / DC converter 112 (the main breaker 111, the cooperative control unit 113, the DC breaker 114, etc.), the connection box 121, and the switch 141 in the distribution board 110 are also omitted.

  The AC / DC converter 112 exemplified here converts the input power into a high-frequency output so as to output the DC voltage of the reference voltage Vref to the pair of DC supply lines Wdc, and the output of the power conversion circuit 4 Transformer T2 having a primary winding connected between the ends, a pair of diodes D7 and D8 for rectifying the voltage induced in the secondary winding of transformer T2 provided with an intermediate tap, and smoothing the rectified voltage And a smoothing capacitor C5 that outputs to the DC supply line Wdc. The feedback circuit 5 feedback-controls the power conversion circuit 4 so that the output of the smoothing capacitor C5 becomes the reference voltage Vref.

  The LED lighting apparatus 1 includes a switching power supply 11 in the apparatus main body in order to generate DC power suitable for lighting of the light source 2 using DC power distributed through the DC supply line Wdc as shown in FIG. is doing. This switching power supply 11 is a voltage feedback type self-excited composite resonance series converter, and while maintaining the low loss and low noise of the switching elements Q1 and Q2, the circuit is greatly simplified compared to the conventional separately excited type. The cost can be reduced and the operation can be performed at a higher frequency.

  A specific circuit configuration of the switching power supply 11 will be described below with reference to FIG.

  A series circuit of first and second switching elements Q1, Q2 made of a power MOSFET is connected between a pair of DC input terminals In1, In2 connected to the DC supply line Wdc. A series resonant circuit of the inductor L, the primary winding L10 of the output transformer T1 and the capacitor C1 is connected in parallel with one of the first and second switching elements Q1 and Q2, and the capacitor C2 (In FIG. 1, an example in which a series resonant circuit and a capacitor C2 are connected in parallel to the second switching element Q2 is shown). In FIG. 1, diodes D1 and D2 connected in antiparallel with switching elements Q1 and Q2, respectively, are body diodes of switching elements Q1 and Q2.

  Further, an intermediate tap is provided in the secondary winding (first secondary winding) of the output transformer T1 to divide it into two (L21, L22), and a full-wave rectifier circuit is formed by diodes D3, D4 that rectify their outputs. The smoothing capacitor C3 and the light source 2 are connected between the cathodes of the diodes D3 and D4 and the intermediate tap. Further, a second auxiliary winding L12 magnetically coupled to the primary winding L10 is provided in the output transformer T1, and a terminal on the connection point side of the switching elements Q1, Q2 in the primary winding L10 of the auxiliary winding L12. A terminal having a polarity opposite to that of the switching element Q2 is connected to the gate of the switching element Q2 via the gate resistor R12 so that the second switching element Q2 can be driven on by the voltage generated in the auxiliary winding L12. Similarly, for the gate drive of the switching element Q1 on the high potential side, a first auxiliary winding L11 magnetically coupled to the primary winding L10 is provided in the output transformer T1, and the primary winding of the auxiliary winding L11 is provided. A terminal having the same polarity as the connection point side terminal of the switching elements Q1 and Q2 in L10 is connected to the gate of the first switching element Q1 via the gate resistor R11, and switching is performed with a voltage generated in the first auxiliary winding L11. The device Q1 is configured to be driven on. Accordingly, the switching elements Q1 and Q2 are alternately turned on by the feedback voltages from the two auxiliary windings L11 and L12 to self-oscillate.

  By the way, the LED lighting fixture 1 of this embodiment has 1st and 2nd switch element SW1, SW2 each connected between the gate-source of each switching element Q1, Q2, and 1st and 2nd switch element SW1. , SW2 includes first and second control circuits 6 and 7 configured by first and second control units Cont1 and Cont2 for on / off control of the switching power supply 11, respectively. The first and second switching elements SW1 and SW2 turn off the first and second switching elements Q1 and Q2, respectively, and each control unit Cont1 and Cont2 is connected to each auxiliary winding L11. , L12 is provided for setting the timing for turning on the switch elements SW1, SW2, that is, the timing for turning off the switching elements Q1, Q2.

  Each control unit Cont1, Cont2 is composed of a series circuit of a diode D5 and a capacitor D4, and detects a reverse voltage of the peak hold circuit 8 connected between both ends of each auxiliary winding L11, L12, and the diode D5, The comparator Comp1 for turning on the switch elements SW1 and SW2, and the delay circuit 12 and the switch SW3 for discharging the charge of the capacitor C4 in preparation for the next cycle, perform the self-excited operation described below. Is. In FIG. 1, illustration of a specific configuration of the first control unit Cont1 is omitted, but the first control unit Cont1 also adopts the same configuration as the second control unit Cont2.

  Below, with reference to FIG. 3, the circuit operation | movement of the LED lighting fixture 1 of this embodiment is demonstrated.

FIG. 3 is an operation waveform diagram of the voltage feedback type self-excited complex resonance series converter according to the present configuration. In the figure, V _Q1 and V _Q2 are drain-source voltages of the switching elements Q1 and Q2, I _Q1 and I _Q2 are drain currents of the switching elements Q1 and Q2, and I _D3 and _ID4 are diodes D3 and D4, V _L10 is the voltage across the primary winding L10 of the output transformer _{T1, V L12} is feedback voltage generated in the second auxiliary winding _{L12, V L11} is the feedback voltage generated in the first auxiliary winding _{L11, V C4} is the peak hold The voltages at both ends of the capacitor C4, V _cont1 and V _cont2 respectively represent the output signals of the control units Cont1 and Cont2 (that is, signals for turning on the switch elements SW1 and SW2) that are the outputs of the comparator Comp1.

Here, the voltage V _L12 Although capacitor C4 between positive will be charged to the on-voltage by a low voltage of the diode D5 from the voltage V _L12, negligible the ON voltage of the diode D5 in the following description The induced voltage generated in the auxiliary winding L12 is assumed to be held at the peak by the peak hold circuit 8 as the voltage V _C4 across the capacitor C4.

The voltage V _L10 applied to the primary winding L10 of the output transformer T1 when the switching elements Q1 and Q2 are alternately turned on and off has a rectangular waveform as shown in FIG. Voltages V _L11 and V _L12 similar to the voltage V _L10 are generated at _L12 . The voltage _{V L12} generated on the auxiliary winding L12 is positive or negative is reversed, the voltage across _{V L10} of the primary winding L10. Here, in the case of current feedback, a sinusoidal resonance current is fed back, whereas in voltage feedback from the output transformer T1, a rectangular wave voltage such as the voltage _VL10 is fed back. It is understood that it is suitable for driving Q1 and Q2.

  Hereinafter, the on / off control of the switching elements Q1, Q2 will be described with reference to FIG. 3 (b) showing a part A of FIG. 3 (a) in detail.

In the example of FIG. 3, in the state of the first switching element Q1 is turned off, the voltage across _{V L12} of the second auxiliary winding _{V L12} rises, the voltage across _{V L12} is first through the gate resistor R12 2 is applied between the gate and the source of the switching element Q2 to turn on the switching element Q2, and after a certain period of time determined by the resonance frequency of the inductor L and the capacitor C1 from the time of rising (time of FIG. 3B) It begins to decline from the peak at t0). Then, below _{(V C4>} V _L12) voltage _{V L12} hold voltage _{V C4} is immediately after the time t0 by the voltage _{V L12} decreases, a difference between the voltage _{V C4} and the voltage _{V L12 (V C4 -V L12} ) Is applied as a reverse voltage to the diode D5. Here, the comparator Comp1 compares the reverse voltage applied to the diode D5 with a predetermined threshold value δ, and when the reverse voltage exceeds the threshold value δ (time t1 in FIG. 3 (b)), the gate − By generating an output signal V _cont2 that turns on the switch element SW2 connected between the sources, the switching element Q2 is turned off (time t2 in FIG. 3B). That is, the comparator Comp1, when the induced voltage _{V L12} generated in the second auxiliary winding L12 is that decreased by more than (the threshold δ in this case) previously determined level than the voltage _{V C4} being the peak hold, on the switch element SW2 Thus, the second switching element Q2 is turned off.

As described above, as a result of the second control circuit 7 (switch element SW2 and control unit Cont2) detecting a decrease in the voltage V _L12 across the second auxiliary winding L12 and turning off the switching element Q2, the primary winding A back electromotive force is generated in L10, the voltage V _L10 across the primary winding L10 rises, and the voltage V _L12 across the auxiliary winding L12 falls quickly from time t2. Thereafter, after delaying the time td from the time t1 by the delay circuit 12 in preparation for the next on-cycle, the charge of the capacitor C4 is discharged by the switch element SW3. As a result, the voltage V _C4 across the capacitor _C4 is reset to zero, The output signal V _{cont2 of} the second control unit Cont2 becomes Low.

Further, as the voltage V _L10 across the primary winding L10 rises, the voltage V _L11 across the auxiliary winding _L11 rises after an appropriate dead time (dead off time) from the time t2 when the switching element Q2 is turned off. (Time t3 in FIG. 3B). The rising voltage V _L11 is applied between the gate and the source of the switching element Q1 via the gate resistor R11 to turn on the switching element Q1, and from the time of rising (the time t3), the inductor L and the capacitor C1 It starts to decrease after a lapse of a fixed time determined by the resonance frequency. Thereafter, the first control circuit 6 (switch element SW1 and control unit Cont1) is switched to the switching element Q1 by the same operation as the second control circuit 7 (switch element SW2 and control unit Cont2) for turning off the switching element Q2 described above. Turn off.

Even if the switching power supply 11 used in the LED lighting apparatus 1 of the present embodiment is self-excited by repeating the above operation, the drain-source voltage V _Q1 , the drain current I _Q1 and the switching element Q2 of the switching element Q1 With respect to the drain-source voltage V _Q2 , the drain current I _Q2 , and the diode currents I _D3 and I _D4 , a waveform very close to the separately excited type shown in FIG. 7 is obtained.

  In such a composite resonance type series converter, ZVS (zero voltage switching), that is, an operation can be performed so that a current starts to flow through the switching elements Q1 and Q2 after the applied voltage of the switching elements Q1 and Q2 decreases. Since the switching loss is extremely small and the recovery loss of the diodes D3 and D4 can be avoided, high frequency can be achieved with high efficiency. Further, since the voltage / current waveform at the time of switching is stable and the ringing of the diodes D3 and D4 can be suppressed, there is an advantage that it is excellent in terms of noise.

  As a result, while maintaining the low loss and low noise of the switching elements Q1 and Q2, the circuit can be greatly simplified and cost-reduced compared to the separate excitation type, and the operation can be performed at a higher frequency (for example, 500 kHz). can do.

  By the way, in this embodiment, the timing demonstrated with reference to FIG. 4 below is employ | adopted as a timing which turns off switching element Q1, Q2.

FIG. 4 is an operating wave diagram of the second excitation winding L12 added to the previously-excited composite resonance series converter shown in FIG. 6 instead of the self-excitation composite resonance series converter of the present embodiment shown in FIG. . In FIG. 4, the same reference numerals as those in FIG. 3 represent the same object, and V _C1 represents the voltage across the capacitor C1. Here, in particular, the waveform of the voltage V _L12 b across the second auxiliary winding L12 is shown in detail.

Here, the relationship between the drive frequency (switching frequency) of the switching elements Q1 and Q2 by the control unit 10 (see FIG. 6) and the series resonance frequency of the inductor L and the capacitor C1 satisfies the condition “resonance frequency> drive frequency”. What I can set to be, it is possible to set as the other current _{I D3, I D4} begins to flow after the one of the current _{I D3, I D4} of the diode D3, D4 has finished flowing. However, in this case, corresponding to the section where the current _{I D3, I D4} of both diodes D3, D4 is interrupted, the waveform of the voltage _{V L10} which is applied to the primary winding L10 of the output transformer T1, shown in FIG. 4 Thus, a step P (time t2 to t2 ′ in FIG. 4) occurs.

  This embodiment pays attention to this step P, and aims at the following effects by matching the timing at which the switching elements Q1, Q2 are turned off with the time of occurrence of the step P (the time t2). .

That is, the period until the step P is generated depends on the series resonance frequency of the inductor L and the capacitor C1, and a stable operating frequency design is possible. Further, the generation of the step P is a result of the interruption of the currents I _D3 and I _D4 of the diodes D3 and D4 on the secondary side of the output transformer T1, which is exactly the switching-off operating point that is ideal in the separate excitation type. By turning off the switching elements Q1 and Q2 when the step P is generated, recovery of the diodes D3 and D4 can be suppressed and ringing can also be suppressed. Furthermore, when the switching elements Q1 and Q2 are turned off at the time when the step P is generated (the time t2), the voltage across the auxiliary windings L11 and L12 rises and the other switching elements Q1 and Q2 are turned on (FIG. 4). Thus, an appropriate dead time can be ensured by the time t3), and as a result, the ZVS operation of the switching elements Q1 and Q2 can be reliably realized.

In the present embodiment, the timing at which the switching elements Q1 and Q2 are turned off is set by the magnitude of the threshold δ compared with the reverse voltage applied to the diode D5 in the comparator Comp1, and the output signal V _cont1 from the comparator Comp1. , V _cont2 (see FIG. 3), the timing at which the switch elements SW1 and SW2 are turned on (time t2 in FIG. 3B) matches the timing of occurrence of the step P described above (time t2 in FIG. 4). The threshold value δ is set.

  According to the LED lighting apparatus 1 having the configuration described above, the pair of DC input terminals In1 and In2 are connected to the AC / DC converter 110 in the distribution board 112 via the DC supply line Wdc, so that the DC supply line is DC power is supplied via Wdc. Therefore, the LED lighting apparatus 1 does not require an AC / DC conversion circuit for converting an AC power source into a DC power source, and the LED lighting apparatus 1 can be reduced in size by a full-wave rectifier and a smoothing capacitor constituting the AC / DC conversion circuit. Is possible. In addition, since the full-wave rectifier is not required, there is an advantage that the circuit efficiency is improved by the loss generated in the full-wave rectifier.

  Furthermore, although it is necessary to connect a line filter (not shown) to the DC input terminals In1 and In2, the DC voltage applied to the DC input terminals In1 and In2 is lower than that of an AC commercial power supply (for example, 24V, 50V). Therefore, the line filter can be reduced in size by shortening the insulation distance of the line filter as compared with the case where an AC commercial power supply is used as input, and the LED lighting apparatus 1 can be reduced in size. be able to.

  Moreover, the control circuits 6 and 7 detect a voltage drop from one of the first and second auxiliary windings L11 and L12, and the first and second switching elements Q1 and Q2 are turned on. In the voltage feedback type self-excited complex resonance series converter, the off-side of the first and second switching elements Q1, Q2 is turned on by driving the off-side of the first side and the other voltage rise. Appropriate switching conditions (ZVS operation) can be realized with a simple configuration, and while maintaining the original characteristics of low loss and low noise, significant circuit simplification and cost reduction can be achieved compared to other excitation types. be able to.

  Further, by increasing the switching frequency of the switching elements Q1, Q2, it is possible to adapt to the downsizing of the LED lighting fixture 1 by downsizing the output transformer T1. More specifically, a general separately-excited composite resonant series converter requires a level shifter to the switching element Q1 on the high potential side. From the viewpoint of frequency followability and loss, the switching frequency of the switching elements Q1 and Q2 However, according to the configuration of the present embodiment, the switching frequency can be set to 500 kHz or more, and the output transformer T1 can be downsized as compared with the separately excited type. be able to. For example, when the switching frequency is set to 500 kHz, it is desirable to employ a core with a small loss at a high frequency (500 kHz) for the output transformer T1.

  The capacitor C2 forming the composite resonance circuit is provided in parallel with at least one of the first and second switching elements Q1 and Q2. However, when the switching frequency is high, the parasitics of the switching elements Q1 and Q2 are provided. Capacitance can be substituted.

(Embodiment 2)
As shown in FIG. 5, the LED lighting apparatus 1 of the present embodiment is charged with a second secondary winding L23 on the secondary side of the output transformer T1 and a voltage induced in the second secondary winding. The secondary battery Batt is provided, and the input to the DC input terminals In1 and In2 is switched to the secondary battery Batt when power supply from the DC supply line Wdc to the DC input terminals In1 and In2 is stopped. 1 is different from the LED lighting apparatus 1.

  The secondary battery Batt is connected between both ends of the second secondary winding L23 via a rectifying diode D6, and voltage is induced in the secondary winding L23 by turning on and off the switching elements Q1 and Q2. Then, it is charged by this induced voltage. Both ends of the secondary battery Batt are connected to a pair of DC input terminals Wdc via switches SW4 and SW5 as input switching means. When both switches SW4 and SW5 are turned on, the output of the secondary battery Batt is connected to the DC input terminal. Input is made to In1 and In2. In addition, you may add the charge control means which controls charging voltage and electric current between the diode D6 and the secondary battery Batt.

  Here, between the pair of DC input terminals In1 and In2, there is provided a power failure detection means 3 for detecting the stop of power supply from the DC supply line Wdc. The switches SW4 and SW5 are connected to the power failure detection means 3. Is turned on in response to an on signal that is output when the stop of power supply is detected.

  According to the configuration described above, when the stop of the power supply from the DC supply line Wdc to the DC input terminals In1 and In2 is detected, the input to the DC input terminals In1 and In2 is switched to the secondary battery Batt. Sometimes the light source 2 can be turned on using the secondary battery Batt as a power source. Therefore, the LED lighting apparatus 1 of this embodiment can be applied to, for example, an emergency light or a guide light.

  Moreover, in the LED lighting fixture of this embodiment, the portable type | mold body (not shown) is employ | adopted as a container which comprises the outline of an instrument main body. The container holds a pair of contacts (not shown) connected to the pair of DC input ends In1 and In2, respectively. These contacts are plug-in connection ports (opened to the DC outlet 131). It is attached to the DC outlet 131 by being inserted into the power feeding unit. Here, the contact inserted into the connection port is connected to the DC supply line Wdc by directly contacting the contact receptacle of the DC outlet 131 in the connection port.

  With this configuration, the LED lighting device 1 can be used as a portable lighting device such as a flashlight by removing the body of the device main body from the DC outlet 131 while the secondary battery Batt is charged. At this time, the input to the DC input terminals In1 and In2 is automatically switched to the secondary battery Batt by the power failure detection means 3 and the switches SW4 and SW5, so that an operation for switching the input is not particularly necessary. In addition, since the LED lighting fixture 1 of this embodiment can be reduced in size by adopting the self-excited switching power supply 11, a portable device can be easily realized, but in addition, for example, a handle is included. A body having a shape more suitable for carrying may be employed.

It is a schematic circuit diagram which shows the structure of Embodiment 1 of this invention. It is a system configuration diagram showing a DC power distribution system in which the LED lighting apparatus is used. It is an operation | movement waveform diagram of LED lighting fixture same as the above. It is an operation | movement waveform diagram of the prior art example shown in FIG. It is a schematic circuit diagram which shows the structure of Embodiment 2 of this invention. It is a schematic circuit diagram which shows the structure of a prior art example. It is an operation | movement waveform diagram same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED lighting fixture 2 Light source 3 Power failure detection means 6 1st control circuit 7 2nd control circuit 8 Peak hold circuit 102 DC apparatus 112 AC / DC converter 131 DC outlet (DC outlet)
AC AC power supply Batt Secondary battery C1 Capacitor C3 Smoothing capacitor Comp1 Comparator D3, D4 Diode (rectifier circuit)
In1, In2 DC input terminal L inductor L10 primary winding L11 first auxiliary winding L12 second auxiliary winding L21, L22 first secondary winding L23 second secondary winding Q1 first switching Element Q2 Second switching element SW1, SW2 Switch element SW4, SW5 Switch (input switching means)
T1 output transformer Wdc DC supply line

Claims (4)

  An LED lighting apparatus for use in a DC power distribution system that supplies DC power output from an AC / DC converter that converts an AC power source to a DC power source to a DC device via a DC supply line wired to a building. A first light source, a pair of direct current input terminals connected to the direct current supply line, first and second switching elements connected in series between the pair of direct current input terminals and alternately controlled on and off, and first and second A series resonant circuit composed of a series circuit of an inductor, an output transformer primary winding and a capacitor connected in parallel with any one of the switching elements, and a voltage induced in the first secondary winding of the output transformer A rectifying circuit for smoothing the output of the rectifying circuit, a smoothing capacitor for smoothing the output of the rectifying circuit and applying it to the light source, and a magnetically coupled to the primary winding of the output transformer The first and second auxiliary windings that turn on the first and second switching elements by the voltage induced in the first and second voltages, respectively, and the first and second auxiliary windings based on the voltages induced in the first and second auxiliary windings, respectively. The device body includes first and second control circuits that turn off the two switching elements, and each control circuit includes a switching element that turns off each switching element when each is turned on, and an induced voltage generated in each auxiliary winding. And a comparator that turns on the switch element when the induced voltage is lower than a hold voltage by the peak hold circuit by a predetermined level or more.   The LED lighting apparatus according to claim 1, wherein a switching frequency of the first and second switching elements is 500 kHz or more.   The appliance main body includes a secondary battery charged with a voltage induced in a second secondary winding provided on the secondary side of the output transformer, and power supply from the DC supply line to the DC input terminal. The power failure detection means for detecting the stop and the input switching means for switching the input to the DC input terminal to the secondary battery when the power failure detection means detects the stop of the power supply. Item 3. An LED lighting apparatus according to Item 2.   It comprises a portable container that constitutes the outer shell of the instrument body, the container holding a contact connected to the DC input end, and the contact connected to the DC supply line 4. The LED lighting apparatus according to claim 3, wherein the LED lighting apparatus is detachably attached to a direct current outlet having a child receiver so as to come into contact with the contact child receiver.

Images