CN204168555U - Power circuit and lighting device - Google Patents
Power circuit and lighting device Download PDFInfo
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- CN204168555U CN204168555U CN201420635569.0U CN201420635569U CN204168555U CN 204168555 U CN204168555 U CN 204168555U CN 201420635569 U CN201420635569 U CN 201420635569U CN 204168555 U CN204168555 U CN 204168555U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The purpose of this utility model is to provide a kind of power circuit of stably working and lighting device.According to execution mode, provide a kind of power circuit, it possesses: bridge circuit, transformer, current rectifying and wave filtering circuit, driver, current detecting part, control part.Direct voltage, by the conducting of switch element, cut-off, is converted to alternating voltage by bridge circuit.Transformer comprise a winding being connected to bridge circuit and with a magnetic-coupled secondary winding of winding, and transformation becomes alternating voltage.Current rectifying and wave filtering circuit comprises the rectifier cell of ac voltage rectifier, and alternating voltage is converted to the output voltage of direct current and is supplied to DC load.The conducting of driver control switch element, cut-off.Current detecting part detects the electric current flowing through switch element.Control part, based on the electric current detected by current detecting part, carries out the abnormality detection of DC load, when detecting abnormal, the control based on the switch element of driver is stopped.
Description
Technical field
Execution mode of the present utility model relates to a kind of power circuit and lighting device.
Background technology
Have a kind of power circuit, it converts input voltage to predetermined output voltage and is supplied to load.Power circuit is such as used in the lighting device comprising the light-emitting components such as light-emitting diode (Light-emitting diode:LED).Power circuit such as to light-emitting component supply electric power, thus makes light-emitting component light.Further, in a power, by use transformer thus by primary side and secondary side electric insulation.In this kind of power circuit, expect stably to work.
Patent documentation 1: Japanese Unexamined Patent Publication 2006-73440 publication
Summary of the invention
The purpose of this utility model is the power circuit and the lighting device that provide a kind of steady operation.
According to execution mode of the present utility model, provide a kind of power circuit, it possesses: bridge circuit, transformer, current rectifying and wave filtering circuit, driver, current detecting part, control part.Described bridge circuit comprises at least 1 switch element, and by the conducting of described switch element, cut-off, direct voltage is converted to the first alternating voltage.Described transformer comprise be connected to described bridge circuit a winding, with a described magnetic-coupled secondary winding of winding, and be the second alternating voltage by described first alternating voltage transformation.Described current rectifying and wave filtering circuit comprises the rectifier cell of described second ac voltage rectifier exported from described secondary winding, and described second alternating voltage is converted to the output voltage of direct current, and described output voltage is supplied to DC load.The conducting of switch element described in described driver control, cut-off.Described current detecting part detects the electric current flowing through described switch element.The described electric current that described control part detects based on described current detecting part, carries out the abnormality detection of described DC load, when detect described abnormal, the control based on the described switch element of described driver is stopped.
According to execution mode of the present utility model, a kind of power circuit and the lighting device that can supply stable electric power to load can be provided.
Accompanying drawing explanation
Fig. 1 is the block diagram of the lighting device schematically represented involved by execution mode.
Fig. 2 (a) ~ Fig. 2 (c) is the chart of an example of the analogue test schematically representing the electric current flowing through switch element.
In figure: 2-AC power; 10-lighting device; 12-lighting load; 14-power circuit; 16-lighting source; 21-filter circuit; 22-rectification circuit; 23-power factor correction circuit; 24-half-bridge circuit; 25-transformer; 26-current rectifying and wave filtering circuit; 30-PFC driver; 31-HB driver; 32-feedback circuit; 33-control part; 34-current detecting part; 35-phase detectors; 36-optical coupler; 41-switch element; 42-inductor; 43-diode; 44-capacitor; 51,52-switch element; 53-capacitor; 55-winding; 56,57-secondary winding; 60-rectification circuit; 61,62-rectifier cell; 64-filtering capacitor; 81-first power supply unit; 82-second source portion; 83-reducing transformer.
Embodiment
Hereinafter, with reference to the accompanying drawings of each execution mode.
In addition, accompanying drawing is schematic or conceptual, and the size etc. between the thickness of each several part and the relation of width, each several part is not defined as identical with reality.Further, even if represent same section, sometimes also show with mutually different sizes or ratio with reference to the accompanying drawings.
In addition, in present specification and each accompanying drawing, identical symbol is marked and suitable detailed to the element identical with the element described by accompanying drawing.
Fig. 1 is the block diagram of the lighting device schematically represented involved by execution mode.
As shown in Figure 1, lighting device 10 possesses: lighting load 12 (DC load) and power circuit 14.Lighting load 12 such as has the lighting source 16 of light-emitting diode (Light-emitting diode:LED) etc.Lighting source 16 also can be such as Organic Light Emitting Diode (Organiclight-emitting diode:OLED) etc.In lighting source 16, such as, use the light-emitting component with forward voltage drop.Lighting load 12, by from the applying of the output voltage of power circuit 14 and the supply of output current, makes lighting source 16 light.The value of output voltage and output current is prescribed according to lighting source 16.
Power circuit 14 has a pair power input terminal 14a, 14b and a pair power output terminal 14c, 14d.AC power 2 is connected with at each power input terminal 14a, 14b.Lighting load 12 is connected to each power output terminal 14c, 14d.In addition, in present specification, " connection " refers to electrical connection, the situation comprising non-physical connection or situation about connecting via other elements.Further, " connection " also comprise via transformer etc. and magnetic-coupled situation.
AC power 2 is such as source power supply.Power circuit 14 by the AC-input voltage VIN supplied from AC power 2 being converted to the output voltage VO UT of direct current and exporting lighting load 12 to, thus makes lighting source 16 light.
The current potential of power output terminal 14c is higher than the current potential of power output terminal 14d.Such as, when lighting source 16 is LED, positive pole is connected to power output terminal 14c, and negative pole is connected to power output terminal 14d.Thus, flow through forward current at lighting source 16, lighting source 16 is lighted.Below, when distinguishing each power output terminal 14c, 14d, power output terminal 14c being called the sub-14c of high-potential output end, power output terminal 14d being called electronegative potential lead-out terminal 14d.
Power circuit 14 comprises: filter circuit 21, rectification circuit 22, power factor correction circuit 23, half-bridge circuit 24 (bridge circuit), transformer 25, current rectifying and wave filtering circuit 26.
Filter circuit 21 is connected to each power input terminal 14a, 14b.Filter circuit 21 such as comprises inductor, capacitor.Filter circuit 21 suppresses the noise comprised the input voltage VIN supplied from AC power 2.
Rectification circuit 22 has: input terminal 22a, 22b, high potential terminal 22c and electronegative potential terminal 22d.Each input terminal 22a, 22b are connected to filter circuit 21.The input voltage VIN that inhibit noise by filter circuit 21 is had in rectification circuit 22 input.Filter circuit 21 can be arranged as required, can omit.Such as, also can omit filter circuit 21, rectification circuit 22 is connected to each power input terminal 14a, 14b.
Rectification circuit 22 is such as diode bridge.The input voltage VIN full-wave rectification that rectification circuit 22 such as will exchange, makes the commutating voltage after full-wave rectification (such as pulsating current voltage) result between high potential terminal 22c and electronegative potential terminal 22d.The current potential of high potential terminal 22c is higher than the current potential of electronegative potential terminal 22d.The current potential of electronegative potential terminal 22d is such as the reference potential of earthing potential or power circuit 14.The current potential of electronegative potential terminal 22d can be any current potential of the current potential lower than high potential terminal 22c.Rectification based on the input voltage VIN of rectification circuit 22 also can be halfwave rectifier.
Power factor correction circuit 23 is connected to rectification circuit 22.Power factor correction circuit 23 suppresses the high order harmonic component of the integral multiple producing supply frequency in commutating voltage.Thus, power factor correction circuit 23 improves the power factor of commutating voltage.
Power factor correction circuit 23 such as comprises: switch element 41, inductor 42, diode 43, capacitor 44.Switch element 41 has electrode 41a ~ electrode 41c.One end of inductor 42 is connected to high potential terminal 22c.The other end of inductor 42 is connected to electrode 41a.Electrode 41b is connected to electronegative potential terminal 22d.The positive pole of diode 43 is connected to electrode 41a.The negative pole of diode 43 is connected to one end of capacitor 44.The other end of capacitor 44 is connected to electronegative potential terminal 22d.That is, in this embodiment, power factor correction circuit 23 is boost chopper.Power factor correction circuit 23 is not limited to this, can be any circuit of the power factor can improving commutating voltage.
Power factor correction circuit 23 such as by making switch element 41 carry out switching manipulation, making input current close to sine wave, thus improving the power factor of commutating voltage.Further, the commutating voltage smoothing after power factor correction circuit 23 utilizes capacitor 44 to make power-factor improvement, thus commutating voltage is converted to direct voltage VDC.The input voltage VIN exchanging 100V (effective value) is such as converted to the direct voltage VDC of about 410V by power factor correction circuit 23.The value of direct voltage VDC is not limited to this, can be arbitrary value.In addition, capacitor 44 can be set as required, also can omit.The commutating voltage of power factor correction circuit 23 such as also after exportable power-factor improvement.
Half-bridge circuit 24 comprises: switch element 51,52 and capacitor 53.Switch element 51 has electrode 51a ~ electrode 51c.Electrode 51a is connected to the terminal of the hot side of capacitor 44.Electrode 51b is connected to the electrode 52a of switch element 52.Electrode 52b is connected to electronegative potential terminal 22d.In this embodiment, direct voltage source is formed by rectification circuit 22 and power factor correction circuit 23.Switch element 51,52 is connected in series relative to direct voltage source.Direct voltage source is not limited to this, can be the free voltage source that can supply direct voltage to half-bridge circuit 24.
Transformer 25 has: winding 55, a secondary winding 56,57.One time winding 55 is connected to half-bridge circuit 24.One end of a winding 55 is connected to electrode 51b and electrode 52a.That is, one end of a winding 55 is connected between 2 switch elements 51,52.The other end of a winding 55 is connected to electronegative potential terminal 22d via capacitor 53.In this embodiment, capacitor 53 is connected between a winding 55 and electronegative potential terminal 22d.In other words, capacitor 53 is connected between a winding 55 and reference potential.Capacitor 53 such as also can be connected between electrode 51b and time winding 55.
Switch element 52, by switch element 51 is become conducting, is become cut-off, thus capacitor 53 is charged via a winding 55 by half-bridge circuit 24.Further, switch element 52, by switch element 51 is become cut-off, is become conducting, thus capacitor 53 is discharged via a winding 55 by half-bridge circuit 24.So, half-bridge circuit 24 by making each switch element 51,52 alternate conduction, cut-off, thus produces alternating voltage at the two ends of a winding 55.That is, the direct voltage VDC supplied from power factor correction circuit 23 is converted to alternating voltage by half-bridge circuit 24.
Further, transformer 25 comprises leakage inductance 55a.In FIG, conveniently and by leakage inductance 55a separate with a winding 55 and illustrate, but in fact leakage inductance 55a is a part for transformer 25.As shown in the figure, leakage inductance 55a is expressed as the inductor being connected in series in a winding 55.
Power circuit 14 forms resonant circuit by transformer 25 and capacitor 53.Specifically, so-called LLC resonant circuit is formed by winding 55, leakage inductance 55a, a capacitor 53.Resonance frequency is determined by winding 55, leakage inductance 55a, a capacitor 53.Thus, by controlling the switching frequency of each switch element 51,52, thus the electric power being supplied to lighting load 12 can be controlled.
Each switch element 41,51,52 is such as n channel-type FET.Such as, electrode 41a, 51a, 52a is drain electrode.Electrode 41b, 51b, 52b are source electrode.Electrode 41c, 51c, 52c are grid.Each switch element 41,51,52 also can be such as p channel-type FET, bipolar transistor or HEMT etc.
Secondary winding 56,57 and winding 55 magnetic coupling.Therefore, if alternating current flows through a winding 55, then alternating current corresponding thereto flows through secondary winding 56,57.Thus, transformer 25 is the second alternating voltage by supplying the first alternating voltage transformation of coming from half-bridge circuit 24.Transformer 25 carries out step-down to supplying the alternating voltage of coming from half-bridge circuit 24.Second alternating voltage is different from the first alternating voltage.The effective value of the second alternating voltage is such as less than the effective value of the first alternating voltage.
So, transformer 25 is set and by primary side and secondary side electric insulation.Thus, the fail safe of lighting device 10 can such as be improved.
Secondary winding 57 is connected in series in secondary winding 56.The tie point of secondary winding 56,57 is connected to electronegative potential terminal 22d by omitting illustrated distribution.The tie point of secondary winding 56,57 is set as the current potential identical with electronegative potential terminal 22d essence.That is, the tie point of secondary winding 56,57 is set to reference potential.
Current rectifying and wave filtering circuit 26 comprises: rectification circuit 60, filtering capacitor 64.Rectification circuit 60 comprises rectifier cell 61,62.Rectification circuit 60 is such as 1 element being provided with 2 rectifier cells 61,62 in 1 assembly.Rectifier cell 61,62 is Schottky barrier diode.Rectifier cell 61,62 also can be other diodes.
The positive pole of rectifier cell 61 be connected to secondary winding 56 with the end of secondary winding 57 opposite side.The negative pole of rectifier cell 61 is connected to one end of filtering capacitor 64.The positive pole of rectifier cell 62 be connected to secondary winding 57 with the end of secondary winding 56 opposite side.The negative pole of rectifier cell 62 is connected to one end of filtering capacitor 64.The other end of filtering capacitor 64 is connected to the tie point of secondary winding 56,57.
Thus, the alternating voltage by transformer 25 step-down is carried out rectification by rectifier cell 61,62 by current rectifying and wave filtering circuit 26, thus is converted to commutating voltage.Further, current rectifying and wave filtering circuit 26 utilizes filtering capacitor 64 to make commutating voltage smoothing, thus commutating voltage is converted to direct voltage.That is, current rectifying and wave filtering circuit 26 generates output voltage VO UT.In this embodiment, current rectifying and wave filtering circuit 26 by each rectifier cell 61,62 by alternating voltage full-wave rectification.Current rectifying and wave filtering circuit 26 also can be such as comprise in each rectifier cell 61,62 any one and by the circuit of alternating voltage halfwave rectifier.That is, current rectifying and wave filtering circuit 26 can be at least comprise the circuit of in each rectifier cell 61,62.
The sub-14c of high-potential output end is connected to the terminal of the hot side of filtering capacitor 64.Electronegative potential lead-out terminal 14d is connected to the tie point of secondary winding 56,57.Thus, output voltage VO UT is had each output between power output terminal 14c, 14d.
Power circuit 14 also comprises: PFC (Power Factor Correction, power factor correction) driver 30 (the second driver), HB (Half Bridge, half-bridge) driver 31 (the first driver), feedback circuit 32, control part 33, current detecting part 34, phase detectors 35.
PFC driver 30 is connected to the electrode 41c of the switch element 41 of power factor correction circuit 23.Predetermined pulse signal is such as input to electrode 41c by PFC driver 30, thus the conducting of control switch element 41, cut-off.That is, PFC driver 30 controls the generation of the direct voltage VDC based on power factor correction circuit 23.
HB driver 31 is connected to the electrode 51c of the switch element 51 of the half-bridge circuit 24 and electrode 52c of switch element 52.HB driver 31 such as by predetermined control signal is input to electrode 51c, 52c, thus the conducting of control switch element 51,52, cut-off.That is, HB driver 31 control based on half-bridge circuit 24 by the conversion of direct voltage VDC to alternating voltage.In other words, control signal is signal.
Be input to the control signal of electrode 51c, 52c such as duty ratio is the pulse signal of 50%.The moment being input to the conducting of the control signal of electrode 52c is contrary with the moment of the conducting of the control signal being input to electrode 51c.Thus, the mutual alternate conduction of each switch element 51,52, cut-off.Further, HB driver 31 control inputs is to the frequency of the control signal of electrode 51c, 52c.Thereby, it is possible to control the magnitude of voltage of the alternating voltage produced at transformer 25.
The duty ratio being input to the control signal of switch element 51 can be different from the duty ratio of the control signal being input to switch element 52.But, the duty ratio of each control signal being input to electrode 51c, 52c is respectively set to identical.Thus, the working stability of half-bridge circuit 24 can such as be made.
Feedback circuit 32 is connected to electronegative potential lead-out terminal 14d.Feedback circuit 32 also can be connected to the sub-14c of high-potential output end.Feedback circuit 32 detects output voltage VO UT and flows through at least one in the output current IO UT of lighting load 12.Feedback circuit 32 based at least one in output voltage VO UT and output current IO UT, FEEDBACK CONTROL HB driver 31.
When lighting source 16 uses the light-emitting components such as LED, the corresponding forward voltage drop of the voltage of lighting source 16 and essence is constant.Therefore, when lighting source 16 uses the light-emitting components such as LED, by feedback circuit 32 is connected to electronegative potential lead-out terminal 14d, thus the electric current flowing through lighting source 16 can be detected exactly.
Feedback circuit 32 such as has differential amplifier circuit.On an input of differential amplifier circuit, input has reference voltage.On another input of differential amplifier circuit, input has the detection voltage of output voltage VO UT or output current IO UT.Differential amplifier circuit exports the voltage corresponding with the difference detecting voltage with reference voltage.
The output voltage of differential amplifier circuit is input to HB driver 31 as feedback signal by feedback circuit 32.HB driver 31 changes each conducting of switch element 51,52, the frequency of cut-off according to the feedback signal carrying out self-feedback ciucuit 32.Thus, HB driver 31 and feedback circuit 32 such as make output current IO UT essence constant.Such as, over-voltage suppression puts on lighting load 12 or overcurrent is supplied to lighting load 12.
Optical coupler 36 is provided with between HB driver 31 and feedback circuit 32.Optical coupler 36 has illuminating part, light accepting part.The signal of telecommunication inputted from feedback circuit 32 is first converted to light by optical coupler 36, and again reverts to the signal of telecommunication and be input into HB driver 31.Thereby, it is possible to by HB driver 31 and feedback circuit 32 electric insulation.Such as, can more effectively by primary side and secondary side insulation.
Current detecting part 34 detects the electric current flowing through each switch element 51,52.In this embodiment, current detecting part 34 is current sense resistor.One end of current detecting part 34 is connected to the electrode 52b of switch element 52.The other end of current detecting part 34 is connected to the electronegative potential terminal 22d of rectification circuit 22.That is, current detecting part 34 is arranged between switch element 52 and electronegative potential terminal 22d.Thus, current detecting part 34 detects the electric current flowing through switch element 52.
Current detecting part 34 such as also can be arranged between switch element 51 and switch element 52, thus the electric current of sense switch element 51.But, as above-mentioned, the other end of current detecting part 34 is connected to electronegative potential terminal 22d.That is, the other end of current detecting part 34 is set as reference potential.Thus, such as easily electric current can be detected.Such as, the circuit detecting electric current can be simplified.Current detecting part 34 also can detect the electric current flowing through switch element 51 and the electric current flowing through switch element 52.Current detecting part 34 is not limited to current sense resistor, such as, can be inductor etc.Current detecting part 34 can be any element that can detect the electric current flowing through each switch element 51,52.
Phase detectors 35 are arranged between current detecting part 34 and control part 33.Phase detectors 35 detect the phase place of the electric current detected by current detecting part 34, and phase detection signal is input to control part 33.In addition, phase detectors 35 can be arranged as required, can omit.Such as, also the testing result of current detecting part 34 can be input to control part 33.
Control part 33 is connected to phase detectors 35 and HB driver 31.Control part 33, based on the phase detection signal inputted from phase detectors 35, detects the exception of lighting load 12.That is, control part 33 is based on the electric current detected by current detecting part 34, detects the exception of lighting load 12.The short circuit of lighting load 12 and open circuit such as detect as exception by control part 33.Further, control part 33, when detecting abnormal, makes the control based on each switch element 51,52 of HB driver 31 stop.That is, control part 33 is when detecting abnormal, stops supplying output voltage VO UT to lighting load 12.
Power circuit 14 also comprises: the first power supply unit 81, second source portion 82, reducing transformer 83.First power supply unit 81 is connected to the output of power factor correction circuit 23.Thus, direct voltage VDC is had in the first power supply unit 81 input.First power supply unit 81 such as passes through direct voltage VDC step-down, thus generates the driving voltage corresponding with PFC driver 30 and HB driver 31 by direct voltage VDC.First power supply unit 81 is such as generated the driving voltage of 15V by the direct voltage VDC of 410V.First power supply unit 81 by generate drive voltage supply to PFC driver 30 and HB driver 31.PFC driver 30 and HB driver 31 are started working according to the supply of the driving voltage from the first power supply unit 81.
Reducing transformer 83 is connected to control part 33 and the first power supply unit 81.The driving voltage step-down that reducing transformer 83 will be come from the input of the first power supply unit 81, converts the driving voltage corresponding with control part 33 to.Further, reducing transformer 83 by conversion after drive voltage supply to control part 33.The driving voltage of 15V is such as converted to the driving voltage of 5V and is supplied to control part 33 by reducing transformer 83.Control part 33 is started working according to the driving voltage supplied from reducing transformer 83.
Second source portion 82 is connected to the terminal of the hot side of filtering capacitor 64.Thus, in second source portion 82, input has output voltage VO UT.Second source portion 82 such as passes through output voltage VO UT step-down, thus generates the driving voltage corresponding with feedback circuit 32 by output voltage VO UT.Second source portion 82 is such as generated the driving voltage of 15V by the output voltage VO UT of about 30V.Second source portion 82 by generate drive voltage supply to feedback circuit 32.Feedback circuit 32 is started working according to the driving voltage supplied from second source portion 82.
So, in power circuit 14, the first power supply unit 81 and second source portion 82 are set.Electric power is supplied from the first power supply unit 81 to the control circuit of primary side and PFC driver 30, HB driver 31 and control part 33.Further, electric power is supplied from second source portion 82 to the control circuit of secondary side and feedback circuit 32.That is, from the primary side of transformer 25 to PFC driver 30, HB driver 31 and control part 33 supply electric power, supplies electric power from the secondary side of transformer 25 to feedback circuit 32.So, in the circuit of primary side and the circuit of secondary side, distinguish power supply, thus can more effectively by primary side and secondary side insulation.
Further, the reference potential that PFC driver 30, HB driver 31, feedback circuit 32 and control part 33 are respective is identical with the current potential essence of the electronegative potential terminal 22d of rectification circuit 22.Thus, the working stability of PFC driver 30, HB driver 31, feedback circuit 32 and control part 33 can such as be made.
At least one of PFC driver 30, HB driver 31, feedback circuit 32 and control part 33 comprises can the semiconductor element of software control.PFC driver 30, HB driver 31, feedback circuit 32 and control part 33 such as use microprocessor.Be arranged at the PFC driver 30 of primary side, HB driver 31 and control part 33 such as can be arranged in 1 processor.PFC driver 30, HB driver 31 and control part 33 can be such as be arranged at the logic module in 1 processor.
Fig. 2 (a) ~ Fig. 2 (c) is the chart of an example of the analogue test schematically representing the electric current flowing through switch element.
The longitudinal axis of Fig. 2 (a) ~ Fig. 2 (c) is the electric current flowing through switch element 52.The transverse axis of Fig. 2 (a) ~ Fig. 2 (c) is the time.Fig. 2 (a) is an example of the electric current flowing through switch element 52 when rated condition.Fig. 2 (b) is the example flowing through the electric current of switch element 52 when load short circuits state.Fig. 2 (c) is the example flowing through the electric current of switch element 52 when load open circuit state.
In analogue test, the electric current (output current IO UT) flowing through load is set to essence constant, changes the resistance value of load, thus simulation rated condition, load short circuits state and load open circuit state.In analogue test, output current IO UT is set to such as 1.1A.Further, in analogue test, such as, be set as rated condition when being 23 Ω by the resistance value of load, during 10 Ω, be set to short-circuit condition, during 50 Ω, be set to open-circuit condition.
As mentioned above, power circuit 14 controls in the mode making output current IO UT become essence constant.Therefore, when changing load resistance, output voltage VO UT also can change.That is, the switching frequency of each switch element 51,52 also can change.
Output voltage VO UT in the analogue test of rated condition is such as 25.3V.Switching frequency in the analogue test of rated condition is such as 53kHz.Now, 1 scale of the transverse axis of Fig. 2 (a) is about 3.77 μ s.
Output voltage VO UT in the analogue test of short-circuit condition is such as 11V.Switching frequency in the analogue test of short-circuit condition is such as 120kHz.Now, 1 scale of the transverse axis of Fig. 2 (b) is about 1.67 μ s.
Output voltage VO UT in the analogue test of open-circuit condition is such as 55V.Switching frequency in the analogue test of open-circuit condition is such as 39kHz.Now, 1 scale of the transverse axis of Fig. 2 (c) is about 5.13 μ s.
In Fig. 2 (a) ~ Fig. 2 (c), interval T1 is that the conducting of switch element 52 is interval.Interval T2 is between the cut-off region of switch element 52.Therefore, in interval T1, there is electric current at the stream between electrode 52a, 52b of switch element 52.Such as, from HB driver 31 to control part 33, input has the information of the switch periods of each switch element 51,52.Control part 33 such as judges T2 between the interval T1 of conducting and cut-off region based on the information of the switch periods of input.
Control part 33 detects in the interval T1 of the conducting of switch element 52, and the absolute value flowing through the electric current of switch element 52 after increase, reduces the interval DS (hereinafter referred to as the interval DS of reduction) of more than predetermined value from the turn-on instant of switch element 52.
Control part 33 such as by sampling to the electric current detected by current detecting part 34 with predetermined period, thus detects the interval DS of reduction.Control part 33 such as calculates the difference of the absolute value of obtained electric current and the absolute value at the electric current of sampling period acquisition before.Further, by the difference that calculates and sampling period, control part 33 judges whether the absolute value of electric current reduces more than predetermined value.Interval T1 after the moment being judged as reducing more than predetermined value such as detects as the interval DS of reduction by control part 33.Such as, the interval reducing more than predetermined value can also be detected as the interval DS of reduction.
Control part 33 such as sets constant value relative to the absolute value of electric current, and when electric current absolute value with before the difference of absolute value of electric current in sampling period be more than steady state value, be judged as reducing more than predetermined value.So, " predetermined value " that use in the detection of the interval DS of reduction is such as the constant value had nothing to do with the order of magnitude of electric current." predetermined value " also can be such as the reduced rate of absolute value relative to the electric current before reducing.Such as, when can reduce more than 20% at the absolute value relative to the electric current before reduction, be judged as reducing more than predetermined value.So, " predetermined value " such as can correspond to the absolute value of the electric current before reducing and change.In addition, " sampling period before " can be front 1 sampling period, also can be the sampling period before multiple cycle.
Sampling period such as can change according to the switch periods (switching frequency) of each switch element 51,52.Such as, by changing the sampling period, the quantity of the absolute value of the electric current detected and switch periods is made to have nothing to do and become constant.Thereby, it is possible to suppress the accuracy of detection reducing interval DS to change with the change of switch periods.Such as, relative to the change of electric current flowing through each switch element 51,52, when the sampling period is set to enough close, the sampling period can be set to constant.Now, the quantity of the absolute value of the electric current of detection also can change according to switch periods.
As shown in Fig. 2 (a), in power circuit 14, each parts are designed to show under rated condition and reduce interval DS.In power circuit 14, each parts are designed to reduce the length (time) of interval DS under rated condition in predetermined scope.Such as, the circuit constants such as half-bridge circuit 24, transformer 25, current rectifying and wave filtering circuit 26 are designed with.
Reducing interval DS is that the voltage of load-side uprises, and each rectifier cell 61,62 of current rectifying and wave filtering circuit 26 does not flow through in fact the interval of electric current.That is, reducing interval DS is the interval not flowing through in fact electric current at the secondary side of transformer 25.In other words, the voltage reduced between each electrode that interval DS is each rectifier cell 61,62 becomes below forward voltage drop, and each rectifier cell 61,62 becomes the interval of cut-off state.In other words, reducing interval DS is that the voltage of filtering capacitor 64 becomes more than predetermined value, and each rectifier cell 61,62 becomes the interval of cut-off state.So, control part 33 detects and reduces interval DS.In other words, control part 33 detects between the cut-off region of each rectifier cell 61,62.In other words, control part 33 detects that the voltage of filtering capacitor 64 is the interval of more than predetermined value.
As shown in Fig. 2 (b), if load is close to short-circuit condition, then compared with normal condition, reduce interval DS and shorten.Such as, reduce interval DS and disappear in fact, flow through the absolute value monotonic increase of the electric current of switch element 52.Its reason can be thought: the resistance step-down of load, and the electric charge put aside in filtering capacitor 64 becomes easy consumption.Therefore, control part 33 detects the length reducing interval DS, when the length of the interval DS of reduction is below lower limit, is judged as lighting load 12 short circuit.Thus, the short circuit of lighting load 12 is detected based on the electric current detected by current detecting part 34.
As shown in Fig. 2 (c), if load is close to open-circuit condition, then compared with normal condition, reduce interval DS elongated.Its reason can be thought: the resistance of load becomes large, and the electric charge put aside in filtering capacitor 64 becomes and is difficult to consume.Therefore, control part 33 detects the length reducing interval DS, when the length of the interval DS of reduction is more than higher limit, is judged as that lighting load 12 is opened a way.Thus, the open circuit of lighting load 12 is detected based on the electric current detected by current detecting part 34.
Control part 33, when short circuit or the open circuit of lighting load 12 being detected, as aforementioned, makes the control that HB driver 31 stops each switch element 51,52.Thereby, it is possible to suppress electric power to continue to supply to the lighting load 12 of abnormality.
In the power circuit of insulated type, such as, have and detect output voltage VO UT or output current IO UT at secondary side, and testing result is input to the structure of the control part of primary side via optical coupler.In such cases, control part detects the exception of load based on the testing result that is transfused to, and the control of detection shutdown switch element according to exception.But, the Yin Wendu of optical coupler and deviation of the characteristic of the characteristic variations produced or each element etc. is larger.Therefore, optical coupler hinders the steady operation of power circuit.Further, when using optical coupler, in order to effectively by primary side and secondary side insulation, must predetermined distance being set between illuminating part and light accepting part, hindering the miniaturization of power circuit.
To this, in the power circuit 14 involved by present embodiment, based on the electric current flowing through the switch element 52 being arranged at primary side, detect the exception of lighting load 12.In power circuit 14, without the need to the exception using optical coupler can detect lighting load 12.Thus, in power circuit 14, compared with using the situation of optical coupler, the characteristic variation etc. produced because of heat can be suppressed, can more stably work.Further, in power circuit 14, such as, the optical coupler be arranged between control part 33 and secondary side can be omitted.Thus, such as component count can be cut down.Power circuit 14 such as can be made more miniaturized.Such as, the manufacturing cost of power circuit 14 can be suppressed to rise.
Above, describe execution mode with reference to concrete example, but have more than and be defined in this, can various distortion be carried out.
In addition, lighting source 16 is not defined in LED, such as, can be organic EL (Electro-Luminescence) or OLED (Organic light-emitting diode, Organic Light Emitting Diode) etc.Can connect or be connected in parallel multiple lighting source 16 in lighting load 12.
In the respective embodiments described above, the half-bridge circuit 24 comprising 2 switch elements 51,52 is shown as bridge circuit.Bridge circuit is not limited to this, such as, can be the full-bridge circuit etc. comprising 4 switch elements.
In the above-described embodiment, showing lighting load 12, but be not limited to this as DC load, such as, can be other DC load such as heater.In the above-described embodiment, showing the power circuit 14 for lighting device 10, but be not limited to this as power circuit, can be any power circuit corresponding with DC load.
Above, some execution modes of the present utility model are illustrated, but these execution modes or embodiment just illustrate, do not limit the intention of the utility model scope.These new execution modes or embodiment can be implemented in other various modes, in the scope not departing from aim of the present utility model, can carry out various omission, displacement, change.In the scope that these execution modes or embodiment and distortion thereof are all included in utility model and aim, and be also contained in the invention and equivalent scope thereof recorded in technical scheme.
Claims (5)
1. a power circuit, is characterized in that, possesses:
At least comprise 1 switch element, and by the conducting of described switch element, cut-off, direct voltage is converted to the bridge circuit of the first alternating voltage;
Comprise a winding being connected to described bridge circuit and with a described magnetic-coupled secondary winding of winding, and be the transformer of the second alternating voltage by described first alternating voltage transformation;
Comprise the rectifier cell of described second ac voltage rectifier exported from described secondary winding, and described second alternating voltage is converted to the output voltage of direct current, described output voltage is supplied to the current rectifying and wave filtering circuit of DC load;
Control the conducting of described switch element, the driver of cut-off;
Detect the current detecting part flowing through the electric current of described switch element;
Based on the described electric current detected by described current detecting part, carry out the abnormality detection of described DC load, when detect described abnormal, make the control part that the control based on the described switch element of described driver stops.
2. power circuit according to claim 1, is characterized in that,
Described control part detects absolute value at the electric current flowing through described switch element from the interval reducing more than predetermined value after the turn-on instant of described switch element increases in the conducting interval of described switch element, when the described length of an interval degree reducing more than predetermined value is below lower limit, be detected as described DC load short circuit, when the described length of an interval degree reducing more than predetermined value is more than higher limit, be detected as described DC load open circuit.
3. power circuit according to claim 2, is characterized in that,
Described control part was sampled to the described electric current detected by described current detecting part with the predetermined sampling period, and calculate the difference of the absolute value of the described electric current obtained and the absolute value at the described electric current of sampling period acquisition before, described in being detected by described difference and described sampling period, reduce the interval of more than predetermined value.
4. the power circuit according to any one in claims 1 to 3, is characterized in that,
The electric power of described driver supplies from the primary side of described transformer.
5. a lighting device, is characterized in that, possesses:
Lighting load;
To the power circuit described in any one in the Claims 1-4 of described lighting load supply electric power.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014060046A JP2015186337A (en) | 2014-03-24 | 2014-03-24 | Power supply circuit and illumination device |
| JP2014-060046 | 2014-03-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204168555U true CN204168555U (en) | 2015-02-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420635569.0U Expired - Fee Related CN204168555U (en) | 2014-03-24 | 2014-10-29 | Power circuit and lighting device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2015186337A (en) |
| CN (1) | CN204168555U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108684122A (en) * | 2018-05-24 | 2018-10-19 | 太仓鸿策腾达网络科技有限公司 | A kind of brightness of illumination regulating system |
| CN110391754A (en) * | 2018-04-23 | 2019-10-29 | 株式会社日立制作所 | Power-converting device and method for detecting abnormality |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113763868B (en) * | 2020-06-01 | 2022-10-11 | 海信视像科技股份有限公司 | Display device and power supply apparatus |
-
2014
- 2014-03-24 JP JP2014060046A patent/JP2015186337A/en active Pending
- 2014-10-29 CN CN201420635569.0U patent/CN204168555U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110391754A (en) * | 2018-04-23 | 2019-10-29 | 株式会社日立制作所 | Power-converting device and method for detecting abnormality |
| CN108684122A (en) * | 2018-05-24 | 2018-10-19 | 太仓鸿策腾达网络科技有限公司 | A kind of brightness of illumination regulating system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2015186337A (en) | 2015-10-22 |
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Granted publication date: 20150218 Termination date: 20171029 |