The utility model content
The technical problems to be solved in the utility model provides a kind of LED multi-path equalizing control circuit, and circuit structure is simple, and cost is low.
The utility model provides a kind of LED multi-path equalizing control circuit, comprising: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and NPN pipe;
One end of described driving resistor connects the anode of corresponding LED branch road, and the other end connects the base stage of described NPN pipe; The anode of each LED branch road connects the anode of described constant-current source;
The emitter of described NPN pipe connects the negative terminal of described constant-current source by sampling resistor, and collector electrode connects the negative terminal of corresponding LED branch road;
Be connected with feedback resistance between the emitter of the NPN pipe in the base stage of the NPN pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the base stage of the NPN pipe in last control circuit and the emitter of the NPN pipe in first control circuit.
Preferably, each control circuit also comprises the diode that is used to revise feedback error;
The anode of described diode connects the base stage of the NPN pipe in the described control circuit, and negative electrode connects the emitter of the NPN pipe in the next adjacent control circuit by described feedback resistance.
Preferably, each control circuit also comprises correction resistance and the correction PNP pipe that is used to revise feedback error,
One end of described correction resistance connects the base stage of the NPN pipe in the described control circuit, and the other end connects the emitter of revising the PNP pipe;
The collector electrode that revises the PNP pipe connects the negative terminal of described constant-current source, and base stage connects the emitter of the NPN pipe in the next adjacent control circuit by feedback resistance.
The utility model also provides a kind of LED multi-path equalizing control circuit, comprising: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and PNP pipe;
One end of described driving resistor connects the negative terminal of corresponding LED branch road, and the other end connects the base stage of described PNP pipe; The anode of each LED branch road connects the collector electrode of described PNP pipe; The negativing ending grounding of each LED branch road;
The emitter of described PNP pipe connects the anode of constant-current source by sampling resistor;
Be connected with feedback resistance between the emitter of the PNP pipe in the base stage of the PNP pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the base stage of the PNP pipe in last control circuit and the emitter of the PNP pipe in first control circuit.
Preferably, each control circuit also comprises the diode that is used to revise feedback error;
The negative electrode of described diode connects the base stage of described PNP pipe, and anode connects the emitter of the PNP pipe in the next adjacent control circuit by described feedback resistance.
Preferably, each control circuit also comprises correction resistance and the correction NPN pipe that is used to revise feedback error;
One end of described correction resistance connects the base stage of the PNP pipe in the described control circuit, and the other end connects the emitter of revising the NPN pipe;
The collector electrode that revises the NPN pipe connects the anode of described constant-current source, and base stage connects the emitter of the PNP pipe in the next adjacent control circuit by feedback resistance.
The utility model also provides a kind of LED multi-path equalizing control circuit, comprising: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and NMOS pipe;
One end of described driving resistor connects the anode of corresponding LED branch road, and the other end connects the grid of described NMOS pipe; The anode of each LED branch road connects the anode of described constant-current source;
The source electrode of described NMOS pipe connects the negative terminal of described constant-current source by sampling resistor, and drain electrode connects the negative terminal of corresponding LED branch road;
Be connected with feedback resistance between the source electrode of the NMOS pipe in the grid of the NMOS pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the grid of the NMOS pipe in last control circuit and the source electrode of the NMOS pipe in first control circuit.
The utility model also provides a kind of LED multi-path equalizing control circuit, comprising: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and PMOS pipe;
One end of described driving resistor connects the negative terminal of corresponding LED branch road, and the other end connects the grid of described PMOS pipe; The anode of each LED branch road connects the drain electrode of described PMOS pipe, the negativing ending grounding of each LED branch road;
The source electrode of described PMOS pipe connects the anode of constant-current source by sampling resistor;
Be connected with feedback resistance between the source electrode of the PMOS pipe in the grid of the PMOS pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the source electrode of the PMOS pipe in the grid of the PMOS in last control circuit and first control circuit.
Compared with prior art, the utlity model has following advantage:
The LED multi-path equalizing control circuit that present embodiment provides is by being provided with control circuit at each LED branch road, and the closed loop collaborative work is controlled each LED branch road and realized current-sharing between each control circuit.When the short circuit of LED lamp occurring in one or more LED branch roads, other LED branch roads stop the electric current of short circuit LED branch road to increase, thereby the electric current of the electric current of realizing each LED branch road during with operate as normal is identical.Because the electric current of each LED branch road can be realized current-sharing, therefore, the electric current of each LED branch road will keep N/one (supposing to have N LED branch road) of the electric current of constant-current source forever.Therefore, which LED branch road this control circuit needn't detect separately the electric current that this short circuit LED branch road is regulated in short circuit separately occurs, and the adjusting of this control circuit is the automatic adjusting of closed loop, and is simple and convenient, and only can realize that with basic device such as simple switching tube and resistance cost is lower.
Embodiment
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, embodiment of the present utility model is described in detail below in conjunction with accompanying drawing.
Referring to Fig. 3, the LED multi-path equalizing control circuit structure chart that this figure provides for the utility model embodiment.
The LED multi-path equalizing control circuit that present embodiment provides comprises: constant-current source S1, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Described control circuit comprises: driving resistor and NPN pipe; Comprise driving resistor Rd1 and NPN pipe Q11 as the control circuit in the LED branch road among Fig. 3; Control circuit in the 2nd LED branch road comprises driving resistor Rd2 and NPN pipe Q21; Control circuit in the nLED branch road comprises driving resistor Rdn and NPN pipe Qn1.
Each LED branch road comprises the LED lamp of n series connection, and as shown in Figure 3, a LED branch road comprises the LED11...LED1n of series connection; The 2nd LED branch road comprises the LED21...LED2n of series connection; The nLED branch road comprises the LEDn1...LEDnn of series connection.
One end of described driving resistor connects the anode of corresponding LED branch road, and the other end connects the base stage of described NPN pipe; The anode of each LED branch road connects the anode of described constant-current source;
With a LED branch road and the 2nd LED branch road is example, and as shown in Figure 3, the end of the driving resistor Rd1 in the control circuit of a LED branch road connects the anode of a LED branch road, and the other end of Rd1 connects the base stage of NPN pipe Q11.
As shown in Figure 3, the emitter of the NPN pipe in each control circuit connects the negative terminal of described constant-current source by sampling resistor, and collector electrode connects the negative terminal of corresponding LED branch road; For example, the emitter of Q11 connects the negative terminal S-of S1 by sampling resistor Rs1.
Be connected with feedback resistance between the emitter of the NPN pipe in the base stage of the NPN pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the base stage of the NPN pipe in last control circuit and the emitter of the NPN pipe in first control circuit.
As shown in Figure 3, the base stage of the NPN in the control circuit of LED branch road correspondence pipe Q11 connects the emitter of the NPN pipe Q21 in the control circuit of the 2nd LED branch road correspondence by feedback resistance Rf1.
The base stage of NPN in the control circuit of the 2nd LED branch road correspondence pipe Q21 connects the emitter of the NPN pipe (not shown) in the control circuit of the 3rd LED branch road correspondence by feedback resistance Rf2.
The base stage of NPN in the control circuit of last LED branch road correspondence pipe Qn1 connects the emitter of the NPN pipe Q11 in the control circuit of a LED branch road correspondence by feedback resistance Rfn.
More than being the annexation of the LED multi-path equalizing control circuit that provides of the utility model embodiment, is the operation principle that example is introduced the utility model embodiment in detail below in conjunction with accompanying drawing 3 with two LED branch roads.
With a LED branch road and the 2nd LED branch road is the operation principle that example is introduced control circuit:
When the circuit operate as normal, a LED branch road and the 2nd LED branch road can be realized good current-sharing, and at this moment, NPN pipe Q11 and Q21 in two control circuits work in critical saturation region.
Supposing has one or more LED short circuits in the LED branch road, then the impedance of a LED branch road will reduce, cause the electric current I c1 of a LED branch road to increase, thereby NPN pipe Q11 enters the amplification region, and along with the electric current of input NPN pipe Q11 collector electrode increases, the electric current of its emitter also increases thereupon.Voltage Vs1 on the sampling resistor Rs1 that NPN pipe Q11 emitter connects also increases.Because the total current Io of constant-current source S1 output is constant, therefore, the Ic1 increase will cause the electric current I c2 on the 2nd LED branch road to reduce, NPN pipe Q21 in the second control circuit enters the saturation region, and along with the electric current of input NPN pipe Q21 collector electrode reduces, the electric current of NPN pipe Q21 emitter also reduces thereupon.Like this, the voltage Vs2 on the sampling resistor Rs2 that connects on the NPN pipe Q21 emitter also reduces.Vs2 reduces and will the base voltage Vb1 of NPN pipe Q11 be reduced, operation principle Vbe1=Vb1-Vs1 according to the NPN pipe, therefore, the Vbe1 of NPN pipe Q11 will reduce, and will stop electric current I c1 to increase like this, simultaneously according to Vbe2=Vb2-Vs2, Vs2 reduces and will cause Vbe2 to increase, resistance reducing of electric current I c2, the final like this electric current of a LED branch road and the 2nd LED branch road that makes trends towards equating, thus the automatic current equalizing of realizing the two paths of LED branch road is regulated.
Need to prove, more than only be to be the operation principle that example is introduced the equalizing control circuit that present embodiment provides with the two paths of LED branch road, be understandable that its operation principle is identical during the LED multi-path branch road, does not repeat them here.
The LED multi-path equalizing control circuit that present embodiment provides is by being provided with control circuit at each LED branch road, and collaborative work is controlled each LED branch road and realized current-sharing between each control circuit.When the short circuit of LED lamp occurring in one or more LED branch roads, other LED branch roads stop the electric current of this short circuit LED branch road to increase, thereby the electric current of the electric current of realizing each LED branch road during with operate as normal is identical.Because the electric current of each LED branch road can be realized current-sharing, therefore, the electric current of each LED branch road will keep N/one (supposing to have N LED branch road) of the electric current of constant-current source forever.Therefore, which LED branch road this control circuit needn't detect separately short circuit occurs, thereby regulates the electric current of this short circuit LED branch road separately, and the adjusting of this control circuit is the automatic adjusting of closed loop, simple and convenient, and only can realize with basic device such as simple switching tube and resistance.
Referring to Fig. 4, this figure is the another example structure figure of LED multi-path equalizing control circuit that the utility model provides.
The difference that the LED multi-path equalizing control circuit that present embodiment provides and Fig. 3 provide is that each control circuit has increased the diode that is used to revise feedback error;
The anode of described diode connects the base stage of the NPN pipe in the described control circuit, and negative electrode connects the emitter of the NPN pipe in the next adjacent control circuit by described feedback resistance.
As shown in Figure 4, the control circuit of a LED branch road has increased diode D11, and the control circuit of the 2nd LED branch road has increased diode D21, and the control circuit of nLED branch road has increased diode Dn1.
The effect that has increased diode can reduce feedback error, the precision that provides electric current to adjust, compensate for temperature drift.
Need to prove that present embodiment also provides a kind of circuit of revising feedback error, referring to Fig. 5, this figure is another example structure of LED multi-path equalizing control circuit figure that the utility model provides.
The correction circuit part that this embodiment is different with embodiment shown in Figure 4 is different, and the correction circuit of this embodiment comprises to be revised resistance and revise the PNP pipe,
One end of described correction resistance connects the base stage of the NPN pipe in the described control circuit, and the other end connects the emitter of revising the PNP pipe;
The collector electrode that revises the PNP pipe connects the negative terminal of described constant-current source, and base stage connects the emitter of the NPN pipe in the next adjacent control circuit by feedback resistance.
As shown in Figure 5, the correction circuit in the control circuit of a LED branch road comprises that revising resistance R 11 manages Q12 with correction PNP; Correction circuit in the control circuit of the 2nd LED branch road comprises to be revised resistance R 21 and revises PNP pipe Q22; Correction circuit in the control circuit of nLED branch road comprises to be revised resistance R n1 and revises PNP pipe Qn2.
In the control circuit that above embodiment provides the NPN pipe, understandable similar to the operation principle of PNP pipe according to the NPN pipe, therefore also can manage with PNP, the control circuit among Fig. 6-8 is made up of PNP pipe and driving resistor.
Referring to Fig. 6, the another control circuit structure chart that this figure provides for the utility model embodiment.
Because the principle of duality of NPN pipe and PNP pipe, the LED multi-path equalizing control circuit that present embodiment provides comprises: constant-current source S1, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and PNP pipe;
One end of described driving resistor connects the negative terminal of corresponding LED branch road, and the other end connects the base stage of described PNP pipe; The anode of each LED branch road connects the collector electrode of described PNP pipe; The negativing ending grounding of each LED branch road;
The emitter of described PNP pipe connects the anode of constant-current source by sampling resistor;
Be connected with feedback resistance between the emitter of the PNP pipe in the base stage of the PNP pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the base stage of the PNP pipe in last control circuit and the emitter of the PNP pipe in first control circuit.
The control circuit of being made up of PNP is identical with the operation principle of the control circuit of being made up of the NPN pipe, does not repeat them here.
The control circuit of being made up of the PNP pipe also can comprise the correction circuit of revising feedback error, and referring to Fig. 7, this correction circuit is realized by revising diode.
The negative electrode of described diode connects the base stage of described PNP pipe, and anode connects the emitter of the PNP pipe in the next adjacent control circuit by described feedback resistance.
Need to prove that referring to Fig. 8, this correction circuit also can be for revising resistance and revising the NPN pipe.
One end of described correction resistance connects the base stage of the PNP pipe in the described control circuit, and the other end connects the emitter of revising the NPN pipe;
The collector electrode that revises the NPN pipe connects the anode of described constant-current source, and base stage connects the emitter of the PNP pipe in the next adjacent control circuit by feedback resistance.
Be understandable that control circuit also can be realized by NMOS pipe and PMOS pipe.Describe in detail below in conjunction with Fig. 9 and Figure 10.
Referring to Fig. 9, this figure is the control circuit of being made up of the NMOS pipe.
The LED multi-path equalizing control circuit that present embodiment provides comprises: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and NMOS pipe;
One end of described driving resistor connects the anode of corresponding LED branch road, and the other end connects the grid of described NMOS pipe; The anode of each LED branch road connects the anode of described constant-current source;
The source electrode of described NMOS pipe connects the negative terminal of described constant-current source by sampling resistor, and drain electrode connects the negative terminal of corresponding LED branch road;
Be connected with feedback resistance between the source electrode of the NMOS pipe in the grid of the NMOS pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the grid of the NMOS pipe in last control circuit and the source electrode of the NMOS pipe in first control circuit.
Referring to Figure 10, this figure is the control circuit of being made up of the PMOS pipe.
The LED multi-path equalizing control circuit that present embodiment provides comprises: constant-current source, a plurality of LED branch road, the corresponding control circuit of each LED branch road;
Each described control circuit comprises: driving resistor and PMOS pipe;
One end of described driving resistor connects the negative terminal of corresponding LED branch road, and the other end connects the grid of described PMOS pipe; The anode of each LED branch road connects the drain electrode of described PMOS pipe, the negativing ending grounding of each LED branch road;
The source electrode of described PMOS pipe connects the anode of constant-current source by sampling resistor;
Be connected with feedback resistance between the source electrode of the PMOS pipe in the grid of the PMOS pipe in each control circuit and the next adjacent control circuit, be connected with feedback resistance between the source electrode of the PMOS pipe in the grid of the PMOS in last control circuit and first control circuit.
Need to prove that the operation principle of being managed the control circuit of forming by NMOS pipe or PMOS is identical with the operation principle of the control circuit of being made up of the NPN pipe, does not repeat them here.
Above embodiment has introduced the method for the LED multi-path current-sharing of the control circuit realization of being made up of NPN pipe, PNP pipe, NMOS pipe and PMOS pipe respectively, no matter use the sort of switching tube, all can realize the purpose of close-loop automatic adjustment between each LED branch road, this control circuit is simple in structure, and cost is low.
The above only is preferred embodiment of the present utility model, is not the utility model is done any pro forma restriction.Though the utility model discloses as above with preferred embodiment, yet be not in order to limit the utility model.Any those of ordinary skill in the art, do not breaking away under the technical solutions of the utility model scope situation, all can utilize the method and the technology contents of above-mentioned announcement that technical solutions of the utility model are made many possible changes and modification, or be revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not break away from technical solutions of the utility model, all still belongs in the scope of technical solutions of the utility model protection any simple modification, equivalent variations and modification that above embodiment did according to technical spirit of the present utility model.