The utility model content
The purpose of this utility model is to solve existing LED power circuit because of not compensating overload or underload state automatically, can not showing that load condition can not finely instruct installation personnel, easily cause power supply to damage or the bad problem of load matched, a kind of improved LED power circuit that can compensate automatically is provided, adopt the LED intelligent guidance that the power supply architecture of coupling LED is installed, not only the mounting technique personnel can find out the state of load intuitively, and can mate LED and power supply voluntarily, when improving the life-span, reduce maintenance cost.
The purpose of this utility model can realize by following technical proposals:
Automatically compensate warning LED power circuit, the pwm circuit that comprises the pfc circuit that receives alternating current, couples with pfc circuit, the output of pwm circuit is coupled with automatic testing circuit of overload and underload automatic testing circuit, wherein overload and be coupled with the signal lamp that shows overload in the automatic testing circuit, be coupled with in the underload automatic testing circuit and show underload signal lamp, underload automatic testing circuit is coupled with the load variations decision circuitry, and the load variations decision circuitry couples by first feedback circuit and pwm circuit.
The automatic testing circuit of described overload comprises that first triode and first that is arranged on described power circuit output end shows the LED lamp, the centre that the base stage of first triode is coupled in first resitstance voltage divider between power circuit output end couples a little, the collector electrode of first triode couples through the positive pole of resistance and power circuit output end, first shows that the anode of LED lamp couples the emitter of first triode, and first shows that the negative electrode of LED lamp couples the negative pole of power circuit output end.
Described underload automatic testing circuit comprises that second triode and second that is arranged on described power circuit output end shows the LED lamp, the centre that the base stage of second triode is coupled in second resitstance voltage divider between power circuit output end couples a little, the emitter of first triode couples through the positive pole of another resistance and power circuit output end, second shows that the anode of LED lamp couples the collector electrode of second triode, and second shows that the negative electrode of LED lamp couples the negative pole of power circuit output end; Described underload automatic testing circuit also comprises the 3rd resitstance voltage divider that is connected between the power circuit output end, and the intermediate point and the load variations decision circuitry of the 3rd resitstance voltage divider couple.
Described load variations decision circuitry comprises two operational amplifiers, an intermediate point of the inverting input of first operational amplifier and the 3rd resitstance voltage divider couples, an output of its in-phase input end and pwm circuit couples, and couple with the in-phase input end of second operational amplifier, the output of first operational amplifier, second operational amplifier all couples by the RC circuit of series connection and inverting input separately, and couples with first feedback circuit.
Described pwm circuit comprises PWM power supply control chip, Balanced Transformer-Less, three-winding teaser transformer, three-winding at least main transformer and power drive level; The output that the output of PWM power supply control chip couples Balanced Transformer-Less, Balanced Transformer-Less couples the elementary winding of teaser transformer; Two secondary winding of teaser transformer couple two field effect transistor of power drive level respectively, and the source electrode of two field effect transistor couples the two ends of the elementary winding of main transformer respectively; Two secondary winding series connection of main transformer, its other end that connects end and one of them secondary winding altogether is the output of power circuit, the other end of another secondary winding and first feedback loop, load variations decision circuitry couple.
Described first feedback loop is the photoelectricity coupling circuit, and the anode of the light-emitting diode of the main transformer of pwm circuit and photoelectricity coupling circuit couples, and couples with the in-phase input end of first operational amplifier of load variations decision circuitry.
Described pfc circuit comprises PFC control chip, power amplifier tube, inductance and second feedback circuit, two outputs of PFC control chip couple two power amplifier tubes respectively, the drain electrode of two power amplifier tubes couples an end of two inductance respectively, the other end of two inductance also connects, the drain electrode of two power amplifier tubes couples a RC circuit respectively and be coupled in output as pfc circuit again behind the parallel circuits of diode, and the output of pfc circuit couples by second feedback circuit and PFC control chip.
The utility model adopts said structure, by automatic testing circuit of the overload that is coupled in power circuit output end and underload automatic testing circuit, can detect the also load condition of display power supply circuit, and can load state information be passed to load variations decision circuitry and prime control circuit by feedback loop, with variation according to load, automatically the output of power circuit is regulated in compensation, avoids the damage of LED load or power supply.
As seen, adopt the utility model of said structure, not only can make the mounting technique personnel can find out the state of load intuitively, and can mate LED and power supply voluntarily, reduce maintenance cost when improving the life-span, more detailed beneficial effect further specifies in specific embodiment.
Embodiment
Below in conjunction with specific embodiments and the drawings the utility model is further described.
Those skilled in the art will appreciate that following embodiment has done simplification to circuit structure, on following circuit structure basis, can realize the technical solution of the utility model.
Automatically compensation warning LED power circuit comprises the pfc circuit that receives alternating current, and the pwm circuit that couples of pfc circuit, the output of pwm circuit is coupled with automatic testing circuit of overload and underload automatic testing circuit, wherein overload and be coupled with the signal lamp that shows overload in the automatic testing circuit, be coupled with in the underload automatic testing circuit and show underload signal lamp, underload automatic testing circuit is coupled with the load variations decision circuitry, and the load variations decision circuitry couples by first feedback circuit and pwm circuit.
Its course of work is, by transformer and rectified current High Level AC Voltage is converted to direct current, use more stable pfc circuit at present, through pwm circuit control, carry out work output according to setup parameter, the electric current and voltage output that realizes regulation is (such as 12V, max 5A), and realize constant current control, load at efferent tap LED, when the LED load does not reach capacity, keep a kind of alarm signal constant (showing yellow such as setting the indicator light mode), (original signal does not work) appears in another kind of alarm signal after LED reaches capacity always, after LED surpasses the LED of load, show a kind of special emergency signal (bright such as redness, perhaps mode such as numeral demonstration etc. is reminded), when returning to the saturation condition urgency signal expression safe range that disappears automatically.
Among the embodiment, pfc circuit can be the stable pfc circuit that adopts existing P FC control chip UCC28061 to constitute.
As shown in Figure 1, pfc circuit comprises PFC control chip U1 (as UCC28061), two power amplifier tube T1001 and T1002, two inductance L 1003 and L1004, and second feedback circuit, two outputs of PFC control chip U1 couple the grid of two power amplifier tube T1001 and T1002 respectively, the drain electrode of two power amplifier tube T1001 and T1002 couples the end of two inductance L 1003 and L1004 respectively, and the other end of two inductance L 1003 and L1004 also connects.As can be seen from Figure 1, the drain electrode of two power amplifier tube T1001 and T1002 couples a RC circuit respectively and be coupled in output as pfc circuit again behind the parallel circuits of a diode, the output Vbus of pfc circuit couples by second feedback circuit and PFC control chip U1, in the present embodiment, second feedback circuit constitutes by the output that is connected on pfc circuit and as the feedback resistance between 7 pin of the UCC28061 of PFC control chip U1.
Those skilled in the art as can be seen, the pfc circuit that Fig. 1 adopts UCC28061 is for simplifying circuit, the element that other is necessary and couple structure can draw from available circuit and general technology general knowledge.
Pfc circuit can be other typical circuit that adopts UCC280061, and other equivalent circuit.
As shown in Figure 2, the output Vbus of the input of pwm circuit and pfc circuit couples, its circuit structure comprises PWM power supply control chip U2, Balanced Transformer-Less is (by the triode T2001 and the T2004 of common collector, the triode T2002 of common collector and T2003 constitute, the emitter that triode T2001 and T2002 connect altogether, the emitter that triode T2003 and T2004 connect altogether is respectively as the output of Balanced Transformer-Less), three-winding teaser transformer T1003, at least three-winding main transformer L2001 and power drive level (field effect transistor T2005 and T2006 by series connection constitute); The output that the output of PWM power supply control chip U2 couples Balanced Transformer-Less, Balanced Transformer-Less couples the elementary winding of teaser transformer T1003; The two ends of two secondary winding of teaser transformer T1003 couple two field effect transistor T2005 of power drive level and drain electrode and the source electrode of T2006 respectively, and the source electrode of two field effect transistor T2005 and T2006 couples the two ends of the elementary winding of main transformer L2001 respectively; Two secondary winding series connection of main transformer, its other end A that connects end B and one of them secondary winding altogether is the output of power circuit, the other end E of another secondary winding and first feedback loop, load variations decision circuitry couple.
As shown in Figure 2, first feedback loop is the photoelectricity coupling circuit, and the anode of the main transformer terminal B of pwm circuit and the light-emitting diode of photoelectricity coupling circuit couples, and couples with the in-phase input end of the first operational amplifier U3 of load variations decision circuitry.
Those skilled in the art as can be seen, the pwm circuit that Fig. 2 adopts pwm chip is for simplifying circuit, the element that other is necessary and couple structure can draw from available circuit and general technology general knowledge.
Pwm circuit can be other typical circuit that adopts UCC25688, and other equivalent circuit.
As shown in Figure 5, the load variations decision circuitry comprises two operational amplifier U3 and U4, an intermediate point of the 3rd resitstance voltage divider of the inverting input of the first operational amplifier U3 and underload automatic testing circuit couples, an output of its in-phase input end and pwm circuit (being end points E) couples, and couple with the in-phase input end of the second operational amplifier U4, the first operational amplifier U3, the output of the second operational amplifier U4 all couples with separately inverting input by the RC circuit of series connection, and couples with negative electrode as the light-emitting diode of the photoelectricity coupling circuit of first feedback circuit.
As shown in Figure 3, the automatic testing circuit that overloads comprises that the first triode Q1 and first that is arranged on power circuit output end shows LED lamp LED1, the centre that the base stage of the first triode Q1 is coupled in first resitstance voltage divider between power circuit output end VLED+ and VLED-couples a little, the collector electrode of the first triode Q1 couples through the anodal VLED+ of resistance and power circuit output end, first shows that the anode of LED lamp LED1 couples the emitter of the first triode Q1, and first shows that the negative electrode of LED lamp LED1 couples the negative pole VLED-of power circuit output end.
As shown in Figure 4, underload automatic testing circuit comprises that the second triode Q2 and second that is arranged between power circuit output end VLED+ and the VLED-shows LED lamp LED2, the centre that the base stage of the second triode Q2 is coupled in second resitstance voltage divider between VLED+ between the power circuit output end and VLED-couples a little, the emitter of first triode couples through the positive pole of another resistance and power circuit output end, second shows that the anode of LED lamp couples the collector electrode of second triode, and second shows that the negative electrode of LED lamp couples the negative pole of power circuit output end; Described underload automatic testing circuit comprises also and is connected between the power circuit output end the 3rd resitstance voltage divider that is made of a plurality of resistance series connection that an intermediate point of the 3rd resitstance voltage divider (being end points D) couples with the in-phase input end of first operational amplifier of load variations decision circuitry.
The prime that those skilled in the art will appreciate that pfc circuit also comprises transformer and rectification circuit, so that High Level AC Voltage is transformed to direct current.
The course of work of present embodiment is as follows:
High Level AC Voltage (as the civil power alternating current 220V) is through transformer, rectification circuit, be transformed to direct current, one termination is gone into the common contact output voltage electric current of inductance L 1003 and L1004, the other end is coupled into 10 pin of UCC28061 as the induction by current input, 14 pin of UCC28061 and 11 pin couple the other end of inductance L 1003 and L1004 respectively with the control output voltage electric current, feed back to 8 pin of UCC28061 by the output Vbus of pfc circuit, constantly detect output and whether realize in the parameter area of setting that stable voltage source offers power amplifier tube T1001 and T1002, whether detection exports conformance with standard, change and adjust the 14th pin and the output of the 11st pin, T1001 and T1002 are changed, at any time adjustment outputs in the parameter area of setting, and output reaches standard.
When unsettled situation is floated in the input generation, fluctuate through inductance L 1003 and L1004 generation output front end, utilize the fluctuation data to feed back to UCC28061, process UCC28061 control T1001 and T1002 control final output voltage.
After pfc circuit produces output voltage, one end is couple to the drain electrode of the field effect transistor T2005 of power drive level, one end is coupled into PMW control chip UCC25600 to control, pass through the Balanced Transformer-Less of the T2001-2004 triode formation of common collector again, offer the elementary winding of teaser transformer, export to the field effect transistor T2005 and the T2006 of power drive level again by two secondary winding of teaser transformer, finally be input to the elementary winding of main transformer, the secondary winding by main transformer outputs to the LED load.
Realize the master control process, after load changes, the power transmission network signal offers operational amplifier, and amplifying device carries out variance analysis according to the parameter of setting, and analysis result outputs to first feedback circuit, offer 2 pin of UCC25600 through Light Coupled Device, UCC25600 is according to the circuit information of feedback, and control T2001-2004 triode is adjusted output current, set maximum output current, the control load maximum power.
When connecing bearing power greater than after setting load, voltage decline phenomenon appears, voltage difference appears in base stage and the collector resistance of the first triode Q1 in the automatic testing circuit of overloading, its work of conducting, and voltage difference appears in the first triode Q1 emitter, signal source output is lighted LED lamp LED1 work, realize the over-saturation phenomenon, the caution load is too much, perhaps short circuit, need to detect loading problem, the queueing problem back light extinguishes automatically.
When connecing bearing power less than after setting working load, the not enough phenomenon of electric current and voltage appears, voltage difference appears in base stage and the emitter resistance of the second triode Q2 of underload automatic testing circuit, its work of conducting, voltage difference appears in the second triode Q2 collector electrode, and signal source output is lighted the 2nd LED lamp LED2 work, realize the over-saturation phenomenon, caution power supply service efficiency is low, can increase load, and the back light that reaches capacity extinguishes automatically.
As seen from last, the LED power circuit in the present embodiment is judged load condition by the load variations decision circuitry that comprises operational amplifier, and feeds back to pwm chip to adjust output; Detect the LED lamp of overload condition and intuitive display with caution by the automatic testing circuit that overloads; The LED lamp that detects underload state and intuitive display by underload automatic testing circuit is with caution, one side is the matched load situation automatically, can intuitively show load condition on the other hand,, improve product useful life and reduce maintenance cost to instruct installation personnel matched load better.
Disclosed all features in this specification, or the step in disclosed all methods or the process except mutually exclusive feature and/or step, all can make up by any way.
Disclosed arbitrary feature in this specification (comprising any accessory claim, summary and accompanying drawing) is unless special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, unless special narration, each feature is an example in a series of equivalences or the similar characteristics.
The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.