CN204231712U - A kind ofly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle - Google Patents
A kind ofly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle Download PDFInfo
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- CN204231712U CN204231712U CN201420707657.7U CN201420707657U CN204231712U CN 204231712 U CN204231712 U CN 204231712U CN 201420707657 U CN201420707657 U CN 201420707657U CN 204231712 U CN204231712 U CN 204231712U
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Abstract
The utility model provides a kind of and utilizes the linear constant current driver circuit for LED of the step-down of charge-discharge principle, at least comprises: voltage input module, detect the voltage detection module of input voltage, the first electric capacity, load and adjust electric current that described load is flow through to realize the constant-current control module of constant current output.It is of the present utility model that to utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle to have system configuration simple, permission LED forces down the half in civil power crest voltage, LED lamp bead number can reduce by half, and only needs less peripheral components just can realize good constant-current characteristics.Due to without the need to magnetic element, less driving power volume and better EMC/EMI characteristic can be realized, and relative to traditional linear arrangement, there is higher power factor value.
Description
Technical field
The utility model relates to LED Drive Control Technique field, particularly relates to a kind ofly utilizing the linear constant current driver circuit for LED of the step-down of charge-discharge principle.
Background technology
In recent years, in the middle of the application of LED, Linear Driving scheme is succinct with its application circuit, does not need inductance, receives an acclaim without the feature of switching noise.But simultaneously due under the fixing condition of input voltage, the selection of LED pressure can be restricted, and therefore, the application of Linear Driving scheme is subject to extreme influence.
Existing linear drive circuit as shown in Figure 1, comprise AC power AC, rectifier bridge, filter capacitor C, load, constant-current control module 11 and sampling resistor Rcs, wherein, described AC power AC is connected across described rectifier bridge, described rectifier bridge output-input voltage Vin; Described filter capacitor C is connected to the two ends of described rectifier bridge, for voltage stabilizing; Described load is LED string, is connected to the output of described rectifier bridge, and described constant-current control module 11 is connected to described load, and one end of described sampling resistor Rcs connects described constant-current control module 11, other end ground connection.Described input voltage vin is charged to described filter capacitor C, described filter capacitor C makes the voltage stabilization at described load, described constant-current control module 11 and described sampling resistor Rcs two ends, and described constant-current control module 11 regulates the electric current in described load path to realize constant current output simultaneously.
Under 220VAC electric main initial conditions, if the filter capacitor C do not amplified after described rectifier bridge, consider optimization system efficiency and reduce the problems such as chip power-consumption, more rational LED pressure should control at about 270V ~ 280V.The cost of LED string occupies significant proportion in whole LED Material Cost, for the application of small-power (LED power output is less than 5W), so high LED pressure, not only reduce the utilance of LED string, add the Material Cost of system, also difficulty is added to this very harsh small size design in low-power applications simultaneously.
Therefore, find the designing requirement applying the Linear Driving scheme of lower LED pressure and put on agenda by those skilled in the art.
Utility model content
The shortcoming of prior art in view of the above, the purpose of this utility model is that providing a kind of utilizes the linear constant current driver circuit for LED of the step-down of charge-discharge principle, for solving the problems such as the high LED string utilance caused of LED pressure is low, cost is high, small size design difficulty is high in prior art.
For achieving the above object and other relevant objects, the utility model provides a kind of and utilizes the linear constant current driver circuit for LED of the step-down of charge-discharge principle, and the described linear constant current driver circuit for LED of the step-down of charge-discharge principle that utilizes at least comprises:
Voltage input module, voltage detection module, the first electric capacity, constant-current control module and load;
Described voltage detection module is connected to the output of described voltage input module, for detecting input voltage;
Described constant-current control module is connected to described voltage input module, described voltage detection module and described load, comprise the first power switch pipe, the second power switch pipe and sampling resistor, described first power switch pipe is connected with the output of described second power switch pipe and is connected to the input of described load by described sampling resistor, adjusts electric current that described load is flow through to realize constant current output for the conducting state by controlling described first power switch pipe and described second power switch pipe;
The input that one end of described first electric capacity is connected to the input of described first power switch pipe, the other end is connected to described second power switch pipe, for carrying out discharge and recharge to guarantee that described load realizes constant current output according to the size of described input voltage;
Described load is connected to the output of described constant-current control module and the input of described voltage input module.
Preferably, described voltage input module comprises AC power and rectifier bridge.
Preferably, described voltage detection module comprises pull-up resistor, pull down resistor, comparator and the second electric capacity, wherein, described pull-up resistor is connected to after connecting with described pull down resistor between described input voltage and ground, two ends described second electric capacity in parallel of described pull down resistor, the normal phase input end of described comparator is connected between described pull-up resistor and described pull down resistor, and the inverting input of described comparator connects the first reference voltage.
Preferably, described constant-current control module also comprises constant-current control circuit, inverter, transmission gate and lower trombone slide, and wherein, the first input end of described constant-current control circuit is connected to the input of described sampling resistor, the second input connects the second reference voltage; The control end that first output of described constant-current control circuit is connected to the control end of described first power switch pipe, the second output is connected to described second power switch pipe by described transmission gate; First control end of described transmission gate connects the output of described voltage detection module, second control end that input connects the output of described voltage detection module, output connects described transmission gate of described inverter; One end of described lower trombone slide is connected to control end, the other end ground connection of described second power switch pipe.
Preferably, also comprise the first diode, the input that anode connects the output of described voltage input module, negative electrode connects described constant-current control circuit of described first diode.
Preferably, also comprise the second diode be connected between described first electric capacity and described first power switch pipe, the anode of described second diode connects described first electric capacity, negative electrode connects described first power switch pipe.
More preferably, also comprise the 3rd diode, the anode of described 3rd diode is connected to the output of described load, negative electrode is connected between described first electric capacity and described second diode.
Preferably, the output head grounding of described sampling resistor.
Preferably, described first power switch pipe and described second power switch pipe are NMOS.
As mentioned above, of the present utility modelly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, there is following beneficial effect:
It is of the present utility model that to utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle to have system configuration simple, permission LED forces down the half in civil power crest voltage, LED lamp bead number can reduce by half, and only needs less peripheral components just can realize good constant-current characteristics.Due to without the need to magnetic element, less driving power volume and better EMC/EMI characteristic can be realized, and relative to traditional linear arrangement, there is higher power factor value.Of the present utility modelly utilize that the step-down of charge-discharge principle linear constant current driver circuit for LED volume is little, power factor value is high, cost is low, can also be programmed by current sampling resistor to LED drive current.
Accompanying drawing explanation
Fig. 1 is shown as the schematic diagram of linear LED drive circuit of the prior art.
Fig. 2 is shown as the schematic diagram utilizing the linear constant current driver circuit for LED of the step-down of charge-discharge principle of the present utility model.
Fig. 3 ~ Fig. 7 is shown as and of the present utility modelly utilizes the step-down of charge-discharge principle linear constant current driver circuit for LED each point waveform schematic diagram.
Element numbers explanation
1 linear LED drive circuit
11 constant-current control modules
2 utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle
21 voltage input modules
211 AC power
212 rectifier bridges
22 voltage detection module
221 comparators
23 constant-current control modules
231 constant-current control circuits
232 inverters
233 transmission gates
24 loads
Embodiment
Below by way of specific instantiation, execution mode of the present utility model is described, those skilled in the art the content disclosed by this specification can understand other advantages of the present utility model and effect easily.The utility model can also be implemented or be applied by embodiments different in addition, and the every details in this specification also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present utility model.
Refer to Fig. 2 ~ Fig. 7.It should be noted that, the diagram provided in the present embodiment only illustrates basic conception of the present utility model in a schematic way, then only the assembly relevant with the utility model is shown in graphic but not component count, shape and size when implementing according to reality is drawn, it is actual when implementing, and the kenel of each assembly, quantity and ratio can be a kind of change arbitrarily, and its assembly layout kenel also may be more complicated.
As shown in Figure 2, the utility model provides a kind of and utilizes the linear constant current driver circuit for LED 2 of the step-down of charge-discharge principle, and the described linear constant current driver circuit for LED 2 of the step-down of charge-discharge principle that utilizes at least comprises:
Voltage input module 21, voltage detection module 22, first electric capacity C1, constant-current control module 23 and load 24;
Described voltage detection module 22 is connected to the output of described voltage input module 21, for detecting input voltage vin;
Described constant-current control module 23 is connected to described voltage input module 21, described voltage detection module 22 and described load 24, comprise the first power switch pipe M1, the second power switch pipe M2 and sampling resistor Rcs, described first power switch pipe M1 is connected with the output of described second power switch pipe M2 and is connected to the input of described load 24 by described sampling resistor Rcs, adjusts electric current that described load 24 is flow through to realize constant current output for the conducting state by controlling described first power switch pipe M1 and described second power switch pipe M2;
The input that one end of described first electric capacity C1 is connected to the input of described first power switch pipe M1, the other end is connected to described second power switch pipe M2, for carrying out discharge and recharge to guarantee that described load 24 realizes constant current output according to the size of described input voltage vin;
Described load 24 is connected to the output of described constant-current control module 23 and the input of described voltage input module 21.
Particularly, as shown in Figure 2, described voltage input module 21 comprises AC power 211 and rectifier bridge 212.Described rectifier bridge 22 comprises two groups of diode groups in parallel, and each diode group comprises two diodes of series connection, and the two poles of the earth of described AC power 211 are connected between two diodes of each diode group.Described voltage input module 21 exports the commutating voltage of sinusoidal voltage.
Particularly, as shown in Figure 2, described voltage detecting mould 22 pieces comprises pull-up resistor Rup, pull down resistor Rdn, comparator 221 and the second electric capacity C2, wherein, described pull-up resistor Rup is connected between described input voltage vin and ground after connecting with described pull down resistor Rdn, the two ends described second electric capacity C2 in parallel of described pull down resistor Rdn, the normal phase input end of described comparator 221 is connected between described pull-up resistor Rup and described pull down resistor Rdn, and the inverting input of described comparator 221 connects the first reference voltage Vref _ ln.
As shown in Figure 2, in the present embodiment, described pull-up resistor Rup and described pull down resistor Rdn carries out dividing potential drop to described input voltage vin, obtains detecting voltage Vln, described detection voltage Vln=Vin*Rdn/ (Rdn+Rup); Described detection voltage Vln is accessed the normal phase input end of described comparator 221, compare with described first reference signal Vref_ln and export comparative result Vcomp, when described detection voltage Vln is less than described first reference signal Vref_ln, described comparative result Vcomp is low level signal, when described detection voltage Vln is greater than described first reference signal Vref_ln, described comparative result Vcomp is high level signal.
Particularly, as shown in Figure 2, described constant-current control module 23 also comprises constant-current control circuit 231, inverter 232, transmission gate 233 and lower trombone slide M3, wherein, the first input end of described constant-current control circuit 231 is connected to the input of described sampling resistor Rcs, the second input connects the second reference voltage Vref _ cc; The control end that first output of described constant-current control circuit 231 is connected to the control end of described first power switch pipe M1, the second output is connected to described second power switch pipe M2 by described transmission gate 233; First control end of described transmission gate 233 connects the output of described voltage detection module 22, second control end that input connects the output of described voltage detection module 22, output connects described transmission gate 233 of described inverter 232; One end of described lower trombone slide M3 is connected to control end, the other end ground connection of described second power switch pipe M2.
As shown in Figure 2, in the present embodiment, described first power switch pipe M1, described second power switch pipe M2 and described lower trombone slide M3 are NMOS.Described first power switch pipe M1 is connected described voltage input module 21 with the drain terminal of described second power switch pipe M2, source connects described sampling resistor Rcs, described constant-current control circuit 231 adjusts the gate voltage Vg1 of described first power switch pipe M1 and the gate voltage Vg2 of described second power switch pipe M2 respectively according to the sampled voltage Vcs of described first power switch pipe M1 and described second power switch pipe M2 output, make the voltage stabilization of described first power switch pipe M1 and described second power switch pipe M2 output at described second reference voltage Vref _ cc, the electric current constant current in described load 24 is adjusted with this, the gate voltage Vg2 of described second power switch pipe M2 is also by the control of the described comparative result Vcomp of described voltage detecting mould 22 output, when described comparative result Vcomp is high level signal, described transmission gate 233 turns off, described lower trombone slide M3 conducting, the gate voltage Vg2 of described second power switch pipe M2 drags down instantaneously, and described second power switch pipe M2 turns off.Current constant control regulates by means of only described first power switch pipe M1 and obtains.
As shown in Figure 2, the output head grounding of described sampling resistor Rcs.
Particularly, as shown in Figure 2, the first diode D1 is also comprised, the input that anode connects the output of described voltage input module 21, negative electrode connects described constant-current control circuit 23 of described first diode D1.
As shown in Figure 2, when described first diode D1 is used for preventing described first electric capacity C1 from discharging, current reflux is to described voltage input module 21.
Particularly, as shown in Figure 2, also comprise the second diode D2 be connected between described first electric capacity C1 and described first power switch pipe M1, the anode of described second diode D2 connects described first electric capacity C1, negative electrode connects described first power switch pipe M1.
As shown in Figure 2, described second diode D2 is for preventing the current reflux on described first power switch pipe M1.
Particularly, as shown in Figure 2, also comprise the 3rd diode D3, the anode of described 3rd diode D3 is connected to the output of described load 24, negative electrode is connected between described first electric capacity C1 and described second diode D2.
As shown in Figure 2, described 3rd diode D3 is for preventing the current reflux in described load 24.
The above-mentioned operation principle of the linear constant current driver circuit for LED of the step-down of charge-discharge principle 2 that utilizes is as follows:
As shown in Figure 2, in the present embodiment, described load 24 is LED string, and under described AC power 211 is 220VAC initial conditions, the threshold voltage of described load 24 is about VF=135V; Under described AC power 211 is 120VAC initial conditions, the threshold voltage of described load 24 is about VF=65V.
As shown in Figure 3, the pressure drop on described voltage input module 21 is the voltage difference Vin-VLEDb of the output of described voltage input module 21 and the input of described voltage input module 21, is the absolute value of sinusoidal voltage.
As shown in Figure 4, with the rising of the pressure drop Vin-VLEDb on described voltage input module 21, described input voltage vin is slowly elevated to the t1 moment, now described input voltage vin satisfies condition: Vin=Vd2+0.7V and Vin<V1, wherein, V1=Vref_ln* (Rdn+Rup)/Rdn, Vd2 is the drain terminal voltage of described power switch pipe M2,0.7V is the forward voltage drop of described first diode D1, and Vref_ln is described first reference voltage.As shown in Figure 4, due to Vin=Vd2+0.7V, described input voltage vin only differs 0.7V with the drain terminal voltage Vd2 of described power switch pipe M2, shows as overlapping of the drain terminal voltage Vd2 of described input voltage vin and described power switch pipe M2 in the diagram.As shown in Figure 2, electric current does not flow through described first electric capacity C1, flow out from the output of described voltage input module 21, get back to the input of described voltage input module 21 through described first diode D1, described second power switch pipe M2, described sampling resistor Rcs and described load 24.Described comparative result Vcomp is low level signal, the conducting of described transmission gate 233, described lower trombone slide M3 turns off, the gate voltage Vg2 of described second power switch pipe is determined by described constant-current control circuit 231, now described power switch pipe M2 conducting, as shown in Figure 5, the sample rate current Ics described sampling resistor Rcs flow through raises final maintenance constant current gradually at Iref=Vref_cc/Rcs.As shown in Figure 6, the pressure drop VC1=Vd2-Vn=Vc1_l on described first electric capacity C1; As shown in Figure 7, the pressure drop VLED in described load 24 rises finally constant in-VLEDb_l gradually.
As described in Figure 4, described input voltage vin is slowly elevated to the t2 moment, and described input voltage vin satisfies condition: Vin=Vd2+0.7v and Vin>V1.As shown in Figure 2, described comparative result Vcomp is high level signal, and described transmission gate 233 turns off, described lower trombone slide M3 conducting, and the gate voltage Vg2 of described second power switch pipe M2 pulled down to ground, and described power switch pipe M2 closes.As shown in Figure 6, pressure drop VC1 on described first electric capacity C1 is constant, still be Vc1_l, due to described input voltage vin-0.7v<Vc1_l, the anode voltage Vn of described second diode D2 is less than 0V, described first power switch pipe M1 is also in closed condition, adds described second power switch pipe M2 and is also closed, so now do not have electric current to flow to described load 24 by described sampling resistor Rcs.Therefore, as shown in Figure 5, described sample rate current Ics sudden change drops to 0A; As shown in Figure 7, pressure drop VLED in described load 24 declines from-VLEDb_l sudden change, ideally 0v should be dropped to, but the electric current flowing through described pull down resistor Rdn and described second electric capacity C2 exists always, and finally flow to described load 24, so the pressure drop VLED of described load 24 cannot drop to 0V completely, the pressure drop VLED now in described load 24 is designated as-VLEDb_h; Meanwhile, as shown in Figure 4, described input voltage vin also jumps to suddenly | VinAC|-(-VLEDb_h).
As described in Figure 4, described input voltage vin is slowly elevated to the t3 moment, Vd2-0.7v>Vc1_l, the namely anode voltage Vn>0.7v of described second diode D2, the drain terminal voltage Vd1>0v of described first power switch pipe M1, as shown in Figure 2, start have electric current to flow out from the output of described voltage input module 21, through described first electric capacity C1, described second diode D2, described first power switch pipe M1, described sampling resistor Rcs and described load 24, flow back to the input of described voltage input module 21 again, electric current in this loop is called capacitance charging current Ich, as shown in Figure 5, described capacitance charging current Ich constantly raises, as shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 slowly raises, as shown in Figure 7, the pressure drop VLED in described load 24 is also in rising.
As shown in Figure 4, described input voltage vin is slowly elevated to the t4 moment, the drain terminal voltage Vd1 >=Vd1_cc_min of described first power switch pipe M1, wherein Vd1_cc_min is the minimum drain terminal Vd1 voltage of current constant when Iref=Vref_cc/Rcs flowing through described first power switch pipe M1.As shown in Figure 5, described capacitance charging current Ich is constant is Iref=Vref_cc/Rcs; As shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 linearly rises, and slope increases; As shown in Figure 7, the pressure drop VLED in described load 24 is constant is-VLEDb_l.
As shown in Figure 4, described input voltage vin drops to the t5 moment, the drain terminal voltage Vd1<Vd1_cc_min of described first power switch pipe M1 after rising again.As shown in Figure 5, described capacitance charging current Ich declines from Iref=Vref_cc/Rcs; As shown in Figure 6, the pressure drop VC1 rate of rise on described first electric capacity C1 slows down; As shown in Figure 7, the pressure drop VLED in described load 24 declines from-VLEDb_l.
As shown in Figure 4, when described input voltage vin drops to the t6 moment, the drain terminal voltage Vd1≤0V of described first power switch pipe M1.As shown in Figure 5, described capacitance charging current Ich reduces to 0A; As shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 is constant in Vc1_h; As shown in Figure 7, the pressure drop VLED in described load 24 is constant in-VLEDb_h.
As shown in Figure 4, when described input voltage vin drops to the t7 moment, because described first electric capacity C1 does not have current path, so as shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 is invariable; As shown in Figure 7, the pressure drop VLED in described load 24 is invariable.As shown in Figure 2, the anode voltage Vn of described second diode D2 declines immediately, as Vd2<VC1, makes Vn<0V, and then described first power switch pipe M1 is closed completely.When the anode voltage Vn of described second diode D2 continues to drop to <VLEDb_h-0.7v (wherein 0.7v is the forward conduction voltage drop of diode D2), when namely Vin drops to <Vc1-(-VLEDb_h), Vin<Vd2, and when Vin continues to decline, the drain terminal voltage Vd2 of described second power switch pipe M1 is held constant at Vc1-(-VLEDb_h), as shown in Figure 4.
As shown in Figure 4, when described input voltage vin drops to the t8 moment, Vin≤V1, as shown in Figure 2, described comparative result Vcomp is low level signal, the conducting of described transmission gate 233, and described lower trombone slide M3 turns off, the gate voltage Vg2 of described second power switch pipe M2 is determined by described constant-current control circuit 231, described second power switch pipe M2 conducting.As shown in Figure 4, due to now Vd2>Vin, described first diode D1 oppositely ends, the electric current now flowing through described second power switch pipe M2 is the discharging current Idis of described first electric capacity C1, due to now Vd2>>Vd2_cc_min (Vd2_cc_min be the current constant that flows through described second power switch pipe M2 minimum Vd2 voltage) when Vref_cc/Rcs, so described capacitance discharge current Idis=Vref_cc/Rcs, as shown in Figure 5.It flows out from described first electric capacity C1, returns described first electric capacity C1 through described second power switch pipe M2, described sampling resistor Rcs, described load 24, described 3rd diode D3.As shown in Figure 7, due to the unexpected conducting of described second power switch pipe M2, and the discharging current Idis of described first electric capacity C1 flows through described load 24, makes the pressure drop VLED of now described load 24 rise to-VLEDb_l from-VLEDb_h sudden change.As shown in Figure 4, the drain terminal voltage Vd2 of described second power switch pipe M2 and described input voltage vin also can be suddenlyd change decline, and fall is all-VLEDb_l-(-VLEDb_h).Further, as shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 also can linear decline from Vc1_h.
As shown in Figure 4, when described input voltage vin drops to the t9 moment, described input voltage vin starts after dropping to VLEDb_l to rise, before the drain terminal voltage Vd2 of described power switch pipe M2 drops to Vd2_cc_min, as shown in Figure 5, described discharging current Idis is constant is Iref=Vref_cc/Rcs; As shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 then continues linear decline; As shown in Figure 7, the pressure drop VLED of described load 24 is also constant is-VLEDb_l.
As shown in Figure 4, when described input voltage vin rose to for 10 moment, after the drain terminal voltage Vd2 of described second power switch pipe M2 drops to Vd2_cc_min, as shown in Figure 5, described discharging current Idis starts to decline from Vref_cc/Rcs; As shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 then continues to decline with more slow slope; As shown in Figure 7, the pressure drop VLED in described load 24 also starts to decline from-VLEDb_l.
As shown in Figure 4, when described input voltage vin rises to the t11 moment, when the drain terminal voltage Vd2 of described second power switch pipe M2 drops near Vin-0.7v (wherein 0.7v is the forward conduction voltage drop of diode D1), described first diode D1 starts forward conduction, as shown in Figure 4, the drain terminal voltage Vd2 of described second power switch pipe M2 stops declining, and rise along with the rising of described input voltage vin, now Vd2=Vin-0.7v, shows as overlapping of the drain terminal voltage Vd2 of described input voltage vin and described power switch pipe M2 equally in the diagram.As shown in Figure 2, described first electric capacity C1 stops discharging to described second power switch pipe M2, the electric current now flowing through described second power switch pipe M2 is the described sample rate current Ics not flowing through described first electric capacity C1, and as shown in Figure 5, described sample rate current Ics starts to rise.It is extracted from the output of described voltage input module 21 by described first diode D1, and through described second power switch pipe M2, described sampling resistor Rcs, described load 24, gets back to the input of described voltage input module 21.As shown in Figure 6, it is Vc1_l that the pressure drop VC1 on described first electric capacity C1 starts constant; As shown in Figure 7, the pressure drop VLED in described load 24 starts to rise.
As shown in Figure 4, when described input voltage vin rises to the t12 moment, during the drain terminal voltage Vd2 >=Vd2_cc_min of described second power switch pipe M2, as shown in Figure 5, described sample rate current Ics starts constant is Iref=Vref_cc/Rcs; As shown in Figure 6, the pressure drop VC1 on described first electric capacity C1 is still constant is Vc1_l; As shown in Figure 7, the pressure drop VLED in described load 24 is also constant is-VLEDb_l.
It is more than the course of work within single cycle 10ms.
It is of the present utility model that to utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle to have system configuration simple, permission LED forces down the half in civil power crest voltage, LED lamp bead number can reduce by half, and only needs less peripheral components just can realize good constant-current characteristics.Due to without the need to magnetic element, less driving power volume and better EMC/EMI characteristic can be realized, and relative to traditional linear arrangement, there is higher power factor value.Of the present utility modelly utilize that the step-down of charge-discharge principle linear constant current driver circuit for LED volume is little, power factor value is high, cost is low, can also be programmed by current sampling resistor to LED drive current.
In sum, the utility model provides a kind of and utilizes the linear constant current driver circuit for LED of the step-down of charge-discharge principle, at least comprises: voltage input module, voltage detection module, the first electric capacity, constant-current control module and load; Described voltage detection module is connected to the output of described voltage input module, for detecting input voltage; Described constant-current control module is connected to described voltage input module, described voltage detection module and described load, comprise the first power switch pipe, the second power switch pipe and sampling resistor, described first power switch pipe is connected with the output of described second power switch pipe and is connected to the input of described load by described sampling resistor, adjusts electric current that described load is flow through to realize constant current output for the conducting state by controlling described first power switch pipe and described second power switch pipe; The input that one end of described first electric capacity is connected to the input of described first power switch pipe 1, the other end is connected to described second power switch pipe, for carrying out discharge and recharge to guarantee that described load realizes constant current output according to the size of described input voltage; Described load is connected to the output of described constant-current control module and the input of described voltage input module.Of the present utility modelly utilize that the step-down of charge-discharge principle linear constant current driver circuit for LED volume is little, power factor value is high, cost is low, can also be programmed by current sampling resistor to LED drive current.So the utility model effectively overcomes various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present utility model and effect thereof only, but not for limiting the utility model.Any person skilled in the art scholar all without prejudice under spirit of the present utility model and category, can modify above-described embodiment or changes.Therefore, such as have in art and usually know that the knowledgeable modifies or changes not departing from all equivalences completed under the spirit and technological thought that the utility model discloses, must be contained by claim of the present utility model.
Claims (9)
1. utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that, the described linear constant current driver circuit for LED of the step-down of charge-discharge principle that utilizes at least comprises:
Voltage input module, voltage detection module, the first electric capacity, constant-current control module and load;
Described voltage detection module is connected to the output of described voltage input module, for detecting input voltage;
Described constant-current control module is connected to described voltage input module, described voltage detection module and described load, comprise the first power switch pipe, the second power switch pipe and sampling resistor, described first power switch pipe is connected with the output of described second power switch pipe and is connected to the input of described load by described sampling resistor, adjusts electric current that described load is flow through to realize constant current output for the conducting state by controlling described first power switch pipe and described second power switch pipe;
The input that one end of described first electric capacity is connected to the input of described first power switch pipe, the other end is connected to described second power switch pipe, for carrying out discharge and recharge to guarantee that described load realizes constant current output according to the size of described input voltage;
Described load is connected to the output of described constant-current control module and the input of described voltage input module.
2. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: described voltage input module comprises AC power and rectifier bridge.
3. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: described voltage detection module comprises pull-up resistor, pull down resistor, comparator and the second electric capacity, wherein, described pull-up resistor is connected to after connecting with described pull down resistor between described input voltage and ground, two ends described second electric capacity in parallel of described pull down resistor, the normal phase input end of described comparator is connected between described pull-up resistor and described pull down resistor, and the inverting input of described comparator connects the first reference voltage.
4. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: described constant-current control module also comprises constant-current control circuit, inverter, transmission gate and lower trombone slide, wherein, the first input end of described constant-current control circuit is connected to the input of described sampling resistor, the second input connects the second reference voltage; The control end that first output of described constant-current control circuit is connected to the control end of described first power switch pipe, the second output is connected to described second power switch pipe by described transmission gate; First control end of described transmission gate connects the output of described voltage detection module, second control end that input connects the output of described voltage detection module, output connects described transmission gate of described inverter; One end of described lower trombone slide is connected to control end, the other end ground connection of described second power switch pipe.
5. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: also comprise the first diode, the input that anode connects the output of described voltage input module, negative electrode connects described constant-current control circuit of described first diode.
6. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: also comprise the second diode be connected between described first electric capacity and described first power switch pipe, the anode of described second diode connects described first electric capacity, negative electrode connects described first power switch pipe.
7. according to claim 6ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: also comprise the 3rd diode, the anode of described 3rd diode is connected to the output of described load, negative electrode is connected between described first electric capacity and described second diode.
8. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: the output head grounding of described sampling resistor.
9. according to claim 1ly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle, it is characterized in that: described first power switch pipe and described second power switch pipe are NMOS.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420707657.7U CN204231712U (en) | 2014-11-21 | 2014-11-21 | A kind ofly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420707657.7U CN204231712U (en) | 2014-11-21 | 2014-11-21 | A kind ofly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle |
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| CN204231712U true CN204231712U (en) | 2015-03-25 |
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| CN201420707657.7U Expired - Fee Related CN204231712U (en) | 2014-11-21 | 2014-11-21 | A kind ofly utilize the linear constant current driver circuit for LED of the step-down of charge-discharge principle |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106535401A (en) * | 2016-11-18 | 2017-03-22 | 贵州恒芯微电子科技有限公司 | Linear constant-current power supply for AC LED |
| CN106604441A (en) * | 2015-10-16 | 2017-04-26 | 得能创科有限公司 | LED driving power supply flow measurement circuit and method |
| CN106658879A (en) * | 2015-08-03 | 2017-05-10 | 华润矽威科技（上海）有限公司 | LED driving device and driving method therefor |
| CN116404852A (en) * | 2023-06-07 | 2023-07-07 | 深圳市微源半导体股份有限公司 | Drive control circuit and direct current conversion circuit |
-
2014
- 2014-11-21 CN CN201420707657.7U patent/CN204231712U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106658879A (en) * | 2015-08-03 | 2017-05-10 | 华润矽威科技（上海）有限公司 | LED driving device and driving method therefor |
| CN106658879B (en) * | 2015-08-03 | 2019-05-21 | 华润矽威科技（上海）有限公司 | LED drive device and its driving method |
| CN106604441A (en) * | 2015-10-16 | 2017-04-26 | 得能创科有限公司 | LED driving power supply flow measurement circuit and method |
| CN106604441B (en) * | 2015-10-16 | 2019-08-09 | 得能创科有限公司 | A kind of the flow measurement circuit and method of LED drive power |
| CN106535401A (en) * | 2016-11-18 | 2017-03-22 | 贵州恒芯微电子科技有限公司 | Linear constant-current power supply for AC LED |
| CN116404852A (en) * | 2023-06-07 | 2023-07-07 | 深圳市微源半导体股份有限公司 | Drive control circuit and direct current conversion circuit |
| CN116404852B (en) * | 2023-06-07 | 2023-09-01 | 深圳市微源半导体股份有限公司 | Drive control circuit and direct current conversion circuit |
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