CN102833903A

CN102833903A - Load drive circuit

Info

Publication number: CN102833903A
Application number: CN2011101594592A
Authority: CN
Inventors: 华桂潮; 葛良安
Original assignee: Led One Hangzhou Co Ltd
Current assignee: Inventronics Hangzhou Co Ltd
Priority date: 2011-06-14
Filing date: 2011-06-14
Publication date: 2012-12-19
Anticipated expiration: 2031-06-14
Also published as: CN102833903B

Abstract

The invention discloses a load drive circuit, which comprises a current control circuit, a current sampling circuit, a current limiting circuit, a compensating pipe set and a direct current voltage source, wherein a load current value of a load set is controlled to be smaller than or equal to a preset current limiting point through the current limiting circuit within a voltage fluctuation range of a power grid into which the load drive circuit is accessed; the current control circuit receives a current signal of the load set sampled by the current sampling circuit, judges whether a current value of the current signal is greater than or equal to a preset current stabilizing point, and controls on/off of each sub-compensating pipe in the compensating pipe set connected to the load set according to a judgment result. Control of a current of the load set in the whole circuit can be finished through the current control circuit, the current sampling circuit and the compensating pipe set even if the voltage fluctuation range of the power grid is larger; current limiting loss of the current limiting circuit is reduced when the voltage fluctuation range of the power grid is larger, and the purpose of improving load driving efficiency is achieved.

Description

Load driving circuits

Technical field

The present invention relates to lighting field, relate to a kind of load driving circuits in particular.

Background technology

In lighting field; Current development is LED (Light Emitting Diode comparatively rapidly; Light-emitting diode) light source; For the led light source that exchanges input, modal drive scheme is to realize the constant-current driving to LED with AC/DC (Alternating Current/Direct Current, ac/dc) Switching Power Supply.

Because Switching Power Supply contains magnetic element, need to solve the high-frequency electromagnetic interference problem, and need the control chip of more complicated; Therefore concerning some low power led light sources; Adopt Switching Power Supply to carry out constant-current driving, the volume ratio of drive circuit is bigger, and cost is also than higher.Therefore, generally use simple LED constant-current drive circuit as shown in Figure 1 to carry out the driving of led light source.

In circuit shown in Figure 1, linear current-limiting circuit 101 is gathered the DC side that is connected in parallel on rectification circuit after (being made up of LED1～LEDn) connects with LED, line voltage is through after the rectification circuit rectification being LED set power supply.This rectification circuit as shown in Figure 1 is positioned at the left side of linear current-limiting circuit and LED set, and L is a live wire, and N is a zero line, and C is a filter capacitor.

In the process of LED illumination, when the voltage that is carried in LED set and linear current-limiting circuit 101 two ends surpassed the total specified voltage of LED set of series connection, the part that exceeds total specified voltage that LED gathers was born by linear current-limiting circuit 101; When total specified voltage that the voltage that is carried in LED set and linear current-limiting circuit 101 two ends is lower than that LED gathers, linear current-limiting circuit 101 saturation conductions, at this moment, the electric current that flows through LED is lower than the current-limiting points of current-limiting circuit.

But; Adopt driving circuit drives led light source in the above-mentioned prior art; When voltage ripple of power network is big, in whole voltage ripple of power network scope, realize constant-current driving to LED, the total specified voltage that then needs LED to gather is approximately equal to the commutating voltage of voltage ripple of power network lower limit.At this moment, in whole LED driving process, when the magnitude of voltage after the line voltage rectification is higher than the total specified voltage of LED set; Need carry out current limliting through 101 pairs of LED set of linear current-limiting circuit, but the very big electric energy of meeting loss, the while also can be reduced the driving efficient of the LED of this moment; Especially during voltage ripple of power network to its higher limit; The power consumption of linear current-limiting circuit 101 will be bigger, and electric energy loss is also bigger, and the driving efficient of the LED of this moment is also lower.

Therefore, the drive circuit that adopts above-mentioned prior art in the bigger scope of voltage ripple of power network during driving LED since only utilize linear current-limiting circuit to LED set carry out current limliting, cause power consumption excessive, thereby reduced the driving efficient of LED.

Summary of the invention

In view of this, the invention provides a kind of load driving circuits, overcoming in the prior art when voltage ripple of power network is big since utilize linear current-limiting circuit to LED set carry out the bigger electric energy of current limliting loss, reduced the problem of the driving efficient of LED.

For realizing above-mentioned purpose, the present invention provides following technical scheme:

A kind of load driving circuits comprises:

Connect with the collections of loads that is driven by said load driving circuits, control the current-limiting circuit of the load current value of said collections of loads smaller or equal to preset current-limiting points, said collections of loads and current-limiting circuit are serially connected with between two outputs of direct voltage source;

The adjustment pipe set parallelly connected with current-limiting circuit with the said collections of loads of connecting; And the son adjustment pipe in the corresponding said adjustment pipe set of each said sub-collections of loads parallel connection; The corresponding preset current stabilization point of each said son adjustment pipe, the son adjustment pipe number in the said adjustment pipe set is greater than 1;

Current sampling circuit, the load current of the collections of loads that is used to sample;

Output connects each said son adjustment pipe control end; The current control circuit that input links to each other with the output of current sampling circuit; After the relatively adjusting of said current control circuit according to current signal that receives and said son adjustment pipe corresponding preset current stabilization point, control the shutoff and the conducting of each said son adjustment pipe.

Preferably, comprising: said preset current-limiting points is more than or equal to said preset current stabilization point.

Preferably, comprising: the said load subclass of connecting between each said son adjustment pipe two ends comprises the load of different numbers.

Preferably, said current-limiting circuit comprises: current regulator diode.

Preferably, said current-limiting circuit comprises:

The current limiting tube of connecting with said collections of loads;

The said current limiting tube of sampling belongs to the current-limiting control circuit of the electric current on the branch road; When the current value that samples during more than or equal to preset current-limiting points; Said current-limiting control circuit is controlled said current limiting tube and is in linear conducting state; And said current-limiting circuit is according to the current value that reduces that samples; The conduction impedance of controlling said current limiting tube reduces, and the load current value of controlling said collections of loads is stabilized in preset current-limiting points; When said conduction impedance was decreased to said current limiting tube and is operated in the saturation conduction state, the electric current on the branch road of said current limiting tube place was less than preset current-limiting points.

Preferably, said current-limiting control circuit comprises: first amplifier is connected in first sampling resistor in the branch road of current limiting tube place;

The output of said first amplifier is connected with the control end of current limiting tube; Inverting input connects the hot end of said first sampling resistor; In-phase input end connects reference signal; Said reference signal is a said collections of loads when being operated in corresponding said current limiting tube corresponding preset current-limiting points, the pressure drop on said first sampling resistor.

Preferably, said current-limiting control circuit also comprises: be connected in the compensating network between said first amplifier inverting input and the output, the inverting input of said first amplifier is connected to the hot end of said first sampling resistor through first resistance.

Preferably, said current-limiting circuit comprises: the adjustment pipe of connecting with said collections of loads, the control end of said adjustment pipe links to each other with the output of said current control circuit output current control signal.

Preferably, each the height adjustment pipe in the said adjustment pipe set, the adjustment pipe in current limiting tube in the said current-limiting circuit or the said current-limiting circuit is triode or field effect metal-oxide-semiconductor.

Preferably, said current sampling circuit comprises: one or more second sampling resistors, the electric current sum of said second sampling resistor of flowing through equals the total current of collections of loads.

Preferably, comprising: be series at one second sampling resistor on the said load driving circuits total current loop, said second sampling resistor, one end connects with reference to ground, and the other end connects the input of said current control circuit;

Perhaps, be series at said current-limiting circuit place branch road respectively, and each said sub two second sampling resistors on the road that close of adjusting pipe place branch road, the hot end of said two second sampling resistors is connected to the input of said current control circuit respectively.

Preferably; Said current control circuit comprises: one or more control units; The corresponding control end that connects one or any said son adjustment pipe of the output of a said control unit; The first input end of said control unit connects reference signal, and second input connects the output of said current sampling circuit.

Preferably; When a plurality of said sons of the corresponding connection of output of a said control unit are adjusted the control end of pipe; Said current control circuit also comprises: be series at one or more reducing transformers of said control unit output, the control end of said son adjustment pipe is directly perhaps through being connected the output of said control unit behind one or more reducing transformers.

Preferably, when said current-limiting circuit was managed for adjustment, said current control circuit comprised:

One or more control units; One of corresponding connection of the output of a said control unit or the control end that individual arbitrarily said son adjustment is managed and/or adjustment is managed; The first input end of said control unit connects reference signal, and second input connects the output of said current sampling circuit.

Preferably, when the output correspondence of a said control unit connected a plurality of said son adjustment pipes and adjusts the control end of pipe, said current control circuit also comprised:

Be series at one or more reducing transformers of said control unit output, said son is adjusted the control end of pipe and adjustment pipe directly perhaps through being connected the output of said control unit behind one or more reducing transformers.

Preferably, said sub-reducing transformer comprises: any one in voltage-stabiliser tube reducing transformer, diode reducing transformer or the resistance drop depressor or combination in any.

Preferably; Said control unit comprises: the inverting input of second amplifier, said second amplifier connects the output of said current sampling circuit; In-phase input end connects reference signal, connects compensating network between the inverting input of said second amplifier and the output;

Perhaps, the 3rd amplifier, the inverting input of said the 3rd amplifier connects the output of said current sampling circuit, and in-phase input end connects reference signal.

Preferably, said current sampling circuit comprises: be series at one second sampling resistor on the said load driving circuits total current loop, said second sampling resistor, one end connects the negative terminal of direct voltage source, and the other end connects said current-limiting circuit and is made as with reference to ground;

Said control unit comprises: the 5th amplifier, the in-phase input end of said the 5th amplifier connect reference signal through the 4th resistance respectively, connect the negative terminal of said direct voltage source through the 5th resistance;

The inverting input of said the 5th amplifier connects with reference to ground;

Be connected compensating network between the inverting input of said the 5th amplifier and the in-phase input end.

Preferably, also comprise: auxiliary source, the input of said auxiliary source utilize the pressure drop of a load subclass to come power taking and power supply to give said current control circuit, and the load number that said load subclass comprises is more than or equal to arbitrary sub load number of adjusting pipe two ends serial connection.

Preferably, when the maximum load that the load number that comprises when the said load subclass that is connected with said auxiliary source equals said son adjustment pipe two ends serial connection is counted, series connection one voltage-stabiliser tube on this son adjustment pipe place branch road.

Preferably, comprising: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit and said auxiliary source are an integrated circuit.

Preferably, comprising: integrated said current-limiting circuit, the set of adjustment pipe, current control circuit, current sampling circuit, auxiliary source, and any one or more load subclass is combined into an integrated circuit.

Preferably, also comprise:

Current compensation circuit when the electric current that detects said adjustment pipe set place branch road is non-vanishing, increases said preset current stabilization point according to preset rules.

Preferably, said current control unit includes only a control unit;

Said control unit first input end connects reference signal through the 6th resistance;

Said current compensation circuit comprises, is connected in each resistance on each said son adjustment pipe branch road, and the hot end of each said resistance is connected between the first input end and said the 6th resistance of said control unit through resistance one to one;

Load number according to the load subclass between serial connection and each the said son adjustment pipe two ends is big more, and the said resistance that connects on this said son adjustment pipe place branch road is big more.

Preferably, comprising: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit, said auxiliary source and said current compensation circuit are an integrated circuit.

Preferably, comprising: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit, said auxiliary source, said current compensation circuit and any one or more said load subclass are combined into an integrated circuit.

Preferably, the input of said load driving circuits inserts electrical network through rectifier bridge.

Preferably, the output of rectifier bridge is parallel with filter capacitor, and the input of rectifier bridge is in series with dividing potential drop electric capacity.

Can know via above-mentioned technical scheme; Compared with prior art; The invention discloses a kind of load driving circuits; Comprise LED collections of loads, current control circuit, current sampling circuit, current-limiting circuit, the set of adjustment pipe and direct voltage source; In the voltage ripple of power network scope that this load driving circuits inserts, the load current value through the set of current-limiting circuit control load is smaller or equal to preset current-limiting points, all kinds of current signals of being sampled by current control circuit received current sample circuit; Whether the current value of judging current signal more than or equal to preset current stabilization point, and according to the conducting and the shutoff of each height adjustment pipe in the adjustment pipe set of the collections of loads of judging of control connection as a result.Even if under the bigger situation of the scope of voltage ripple of power network; Can pass through current control circuit, current sampling circuit and the set of adjustment pipe and accomplish control collections of loads electric current in the entire circuit; Reduce current-limiting circuit and when voltage ripple of power network is big, carry out the loss of current limliting, realize improving the purpose that LED drives efficient.

Description of drawings

In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is embodiments of the invention, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to the accompanying drawing that provides.

Fig. 1 is disclosed a kind of LED constant-current drive circuit sketch map in the prior art;

Fig. 2 is the embodiment of the invention one disclosed a kind of load driving circuits sketch map;

Fig. 3 is example one disclosed a kind of load driving circuits sketch map of the present invention;

Fig. 4 is example two disclosed a kind of load driving circuits sketch mapes of the present invention;

Fig. 5 a is the sketch map of example three disclosed current-limiting circuits of the present invention;

Fig. 5 b is example three disclosed a kind of load driving circuits sketch mapes of the present invention;

Fig. 6 is example four disclosed a kind of load driving circuits sketch mapes of the present invention;

Fig. 7 is example five disclosed a kind of load driving circuits sketch mapes of the present invention;

Fig. 8 is example five disclosed another kind of load driving circuits sketch mapes of the present invention;

Fig. 9 is example six disclosed a kind of load driving circuits sketch mapes of the present invention;

Figure 10 is example seven disclosed a kind of load driving circuits sketch mapes of the present invention;

Figure 11 is example eight disclosed a kind of load driving circuits sketch mapes of the present invention;

Figure 12 is example eight disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 13 is example eight disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 14 is example eight disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 15 is example eight disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 16 a is example nine disclosed a kind of load driving circuits sketch mapes of the present invention;

Figure 16 b is example nine disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 16 c is example nine disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 16 d is example nine disclosed another kind of load driving circuits sketch mapes of the present invention;

Figure 17 is the disclosed a kind of load driving circuits sketch map of example ten of the present invention (embodiment two);

Figure 18 is example 11 disclosed a kind of load driving circuits sketch mapes of the present invention;

Figure 19 is the embodiment of the invention three disclosed a kind of load driving circuits sketch mapes;

Figure 20 is the embodiment of the invention three disclosed another kind of load driving circuits sketch mapes;

Figure 21 is the embodiment of the invention three disclosed another kind of load driving circuits sketch mapes;

Figure 22 is the embodiment of the invention four disclosed a kind of load driving circuits sketch mapes.

Embodiment

For quote and know for the purpose of, the explanation of the technical term that hereinafter uses, write a Chinese character in simplified form or abridge and sum up as follows:

LED:Light Emitting Diode, light-emitting diode;

AC/DC:Alternating Current/Direct Current, ac/dc;

MOS:Metal-Oxide-Semiconductor, FET.

To combine the accompanying drawing in the embodiment of the invention below, the technical scheme in the embodiment of the invention is carried out clear, intactly description, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the present invention's protection.

Can know by background technology, adopt drive circuit of the prior art in the bigger scope of voltage ripple of power network during driving LED and since only utilize linear current-limiting circuit to LED set carry out current limliting, cause power consumption excessive easily, thereby reduce the problem that LED drives efficient.Therefore; The invention discloses a kind of load driving circuits; Under the bigger situation of the scope of voltage ripple of power network; Accomplish control through current control circuit, current sampling circuit and the set of adjustment pipe, reduce current-limiting circuit and when voltage ripple of power network is big, carry out the loss of current limliting, realize improving the purpose that LED drives efficient collections of loads electric current in the entire circuit.Particular circuit configurations describes through following examples.

Embodiment one

See also accompanying drawing 2, be a kind of load driving circuits sketch map disclosed by the invention, mainly comprise: collections of loads A, adjustment pipe set B, current-limiting circuit 11, current control circuit 12, current sampling circuit 13 and direct voltage source 14.

The collections of loads A that need drive comprises that by at least one the load subclass of LED forms (LED is load), and as shown in Figure 2, collections of loads comprises load subclass A1, A2......An in the present embodiment, and wherein n is greater than 1.

In each load subclass, comprise at least one LED.As shown in Figure 2, the LED in the whole collections of loads comprises: LED1～LEDx, and load subclass A1 comprises: LED1～LEDa; Load subclass A2 increases some LED on the basis of load subclass A1; As shown in Figure 2, in fact the LED among the load subclass A2 comprises: LED1～LEDb, and the like; LED among the load subclass An comprises: LED1～LEDn, wherein x＞n＞b＞a is counted in load.

Current-limiting circuit 11 and collections of loads A are serially connected with between two outputs of direct voltage source, and said current-limiting circuit is used for the load current value of control load set A smaller or equal to preset current-limiting points.Should preset current-limiting points be the constant current value of collections of loads A under the effect of current-limiting circuit.

Adjustment pipe set B is parallelly connected with current-limiting circuit 21 with the collections of loads A that connects, and comprises n son adjustment pipe in this adjustment pipe set B, the corresponding preset current stabilization point of each son adjustment pipe.As shown in Figure 2; N son adjustment pipe is one by one corresponding to adjustment pipe 1, adjustment pipe 2...... adjustment pipe n; In the process parallelly connected with collections of loads A and current-limiting circuit 21; Be specially: each son adjustment pipe, promptly adjustment pipe 1～adjustment pipe n respectively with the load subclass A1～load subclass An of corresponding label and the series arm parallel connection of current-limiting circuit 11, i.e. each sub-collections of loads (corresponding son adjustment pipe of parallel connection (n is managed in the 1～adjustment of adjustment pipe) of A1～An).

Need to prove that the LED number in the load subclass of connecting between each son adjustment pipe (adjustment pipe 1～adjustment pipe n) two ends has nothing in common with each other, and the corresponding separately preset current stabilization point of adjustment pipe 1～adjustment pipe n.Should preset current stabilization point be the constant current value of collections of loads A under the effect of current-limiting circuit 11.

Wherein, Pairing each the preset current stabilization point of adjustment pipe 1～adjustment pipe n can equate, also can not wait, as long as satisfy; Power network fluctuation makes when the voltage of direct voltage source reduces gradually; Each son adjustment pipe conducting successively is in proper order: the LED number that is connected in series between the son adjustment pipe two ends is few more, and this son adjustment pipe is guide's reduction of fractions to a common denominator stream more, i.e. the LED number of deepening is that the condition that increases gradually gets final product.When pairing each the preset current stabilization point of said adjustment pipe 1～adjustment pipe n does not wait; More excellent is chosen as; The LED number that is connected in series between the son adjustment pipe two ends is many more; Its pairing preset current stabilization point is more little, i.e. son adjustment pipe corresponding preset current stabilization point reduces according to the increase of the number of loads of the collections of loads of connecting between its two ends.

Current sampling circuit 13; Its sampled signal output is connected with the input of current control circuit 12; Be used for the load current of collections of loads A is sampled, the total current of the load driving circuits of promptly sampling, the current signal that sampling is obtained is transferred to current control circuit 12.

Current control circuit 12; Output connects the control end of the son adjustment pipe (adjustment pipe 1～adjustment pipe n) in the adjustment pipe set B; Input links to each other with the sample rate current signal output part of current sampling circuit 13; Be used for received current sample circuit 13 electric current transmitted signals; Whether the current value of judging this current signal more than or equal to above-mentioned adjustment pipe 1～adjustment pipe n corresponding preset current stabilization point, when the current value of this current signal during more than or equal to a certain preset current stabilization point, controls the pairing son adjustment of this preset current stabilization point and manages shutoff; When the current value of this current signal during less than a certain preset current stabilization point; Control the pairing son adjustment pipe of this preset current stabilization point and be in linear conducting state, along with the current value of the current signal of said sampling is more little, the conduction impedance of son adjustment pipe is also more little; The place branch road shunting of son adjustment pipe is many more; Guarantee adequate food and conducting until pairing son adjustment, the current value of current signal diminishes again, and pairing son adjustment pipe still is in saturation conduction.

Wherein, the pairing preset current stabilization point of adjustment pipe 1～adjustment pipe n is designated as I1～In successively, and current-limiting circuit 11 corresponding preset current-limiting points are designated as Ix.The preset current-limiting points Ix of current-limiting circuit 11 and the magnitude relationship of adjusting all the adjustment pipe corresponding preset current stabilization points in the pipe set B do not do qualification here.

Wherein, Preferably, the preset current-limiting points Ix of current-limiting circuit 11 is more than or equal to all the adjustment pipe corresponding preset current stabilization points in the adjustment pipe set B, i.e. the current-limiting circuit metering function that taken the lead in; When its metering function was invalid, the son adjustment in the set of adjustment pipe was managed just conducting successively and is played the current stabilization effect.

Specifically, when the electric current of the collections of loads of flowing through increases, even when surpassing the rated current of collections of loads; Current-limiting circuit plays metering function through the impedance that increases himself; Make the current stabilization of collections of loads in preset current-limiting points, at this moment, all not conductings of son adjustment pipe in the adjustment pipe set B; When the electric current of the collections of loads of flowing through reduces; Make impedance that current-limiting circuit reduces himself to minimum even be zero; Can not be when the preset current-limiting points with the current stabilization of collections of loads; Just conducting shunting successively of son adjustment pipe in the adjustment pipe set makes that (electric current of A1～An) reduces, and makes that also (A1～An) impedance of the parallel branch of composition reduces for the load subclass of son adjustment pipe and its two ends serial connection for the load subclass that is connected in series between the son adjustment pipe two ends; The residual negative carrier set A of then connect with son adjustment pipe-(the electric current increase of A1～An) finally makes the outputting current steadily of load driving circuits at preset current stabilization point.

In addition, group adjustment pipe corresponding preset current stabilization point also can reach technique effect of the present invention during greater than the preset current-limiting points Ix of current-limiting circuit 11; And difference only is, when the electric current of the collections of loads of flowing through increases, and current-limiting circuit is when playing metering function; Adjustment pipe is integrated under the effect of current control circuit, and conducting plays the current stabilization effect; At this moment, the current stabilization of current-limiting circuit place branch road is in preset current-limiting points, and the outputting current steadily of load driving circuits is at preset current stabilization point; The power consumption of the son adjustment pipe of conducting is bigger, and the efficient of load driving circuits is lower.

In the scope of voltage ripple of power network; Electric current among the collections of loads A is under the effect of current-limiting circuit 11; Its maximum is no more than preset current-limiting points, through the effect of 12 pairs n son adjustment of current control circuit pipe, its minimum value is stabilized in n the preset current stabilization point place of minimum that son adjustment pipe is corresponding again; Therefore, the electric current of collections of loads A changes small along with the variation of input direct voltage.Even if under the bigger situation of voltage ripple of power network scope, driving efficient that also can proof load LED, and can not increase the loss on the current-limiting circuit 11.

On the basis of the invention described above the disclosed embodiments one, the current-limiting circuit 11 among Fig. 2 can specifically be made up of following device or circuit.

Example one

As shown in Figure 3, on the basis of Fig. 2, this current-limiting circuit 11 can be current regulator diode D1, and the current-limiting points of this current regulator diode D1 is near the rated current of collections of loads A.

In the scope of voltage ripple of power network; The pressure drop U when if the direct voltage of direct voltage source is operated in preset current-limiting points more than or equal to collections of loads A; Pressure reduction between direct voltage and all the load subclass is born by current regulator diode D1; So that the pressure drop on the proof load set A is U still, make the final constant current-limiting points of electric current of collections of loads A at current regulator diode D1.Opposite, if the pressure drop U when direct voltage is operated in the corresponding preset current-limiting points less than all collections of loads, the current regulator diode D1 of this moment will not play metering function.

Example two

As shown in Figure 4; On the basis of Fig. 2; This current-limiting circuit 11 can be made up of current limiting tube 111 and current-limiting control circuit 112; This current limiting tube 111 is connected with collections of loads A, and current-limiting control circuit 112 is used for through the electric current on the sampling current limiting tube 111 place branch roads operating state of current limiting tube 111 being controlled.

Electric current on the current-limiting control circuit 112 sampling current limiting tubes 111 place branch roads; Judge that whether the current value that samples is more than or equal to adjustment pipe corresponding preset current-limiting points; If then controls current limiting tube 111 and be operated in linear conducting state, and current value is big more; The conduction impedance of current limiting tube is big more, can make collections of loads A finally be operated in preset current-limiting points Ix; If, then do not control current limiting tube 111 and be operated in the saturation conduction state.

Need to prove that on the basis of above-mentioned example two, the different structure according to current-limiting control circuit 112 discloses following example again.

Example three

Shown in Fig. 5 a; On the basis of Fig. 4; This current-limiting control circuit 112 is made up of the first amplifier U1 and the first sampling resistor Rs1, and this first sampling resistor Rs1 is serially connected with in the current limiting tube 111 place branch roads, and the inverting input of the first amplifier U1 connects the hot end of this first sampling resistor Rs1; In-phase input end then connects reference signal Vref1, and the output of the first amplifier U1 then is connected to the control end of current limiting tube 111.

When this reference signal Vref1 is operated in the preset current-limiting points of current-limiting circuit 11 for collections of loads A, the pressure drop on the first sampling resistor Rs1.

On the basis of foregoing circuit; When the electric current of current limiting tube 111 place branch roads increases, the pressure drop on the first sampling resistor Rs1 will increase, and the current potential of the inverting input of the first amplifier U1 also will raise; The output current potential of the first amplifier U1 then reduces; The conduction impedance of current limiting tube 111 is increased, thereby reduce the electric current of said current limiting tube 111 place branch roads, finally make the current stabilization of collections of loads A in preset current-limiting points.

Shown in Fig. 5 b; On the basis of Fig. 4, the negative terminal of direct voltage is made as with reference to ground, the first sampling resistor Rs1 is connected current limiting tube 111 and with reference between the ground; The in-phase input end of the first amplifier U1 connects reference signal Vref1; Connect compensating network 113 between inverting input and the output, and inverting input is connected to the hot end of Rs1 through first resistance R 1, the output of the first amplifier U1 connects the control end of current limiting tube 111.When dc voltage fluctuation made that current limiting tube 111 place branch currents increase, at this moment, the pressure drop on the first sampling resistor Rs1 increased; The output of the first amplifier U1 is reduced; The impedance of current limiting tube 111 increases, and finally makes the electric current I o of collections of loads A be stabilized in preset current-limiting points Ix place, thereby guarantees under the bigger situation of voltage ripple of power network scope; Still guarantee the driving efficient of load LED, and can not increase the loss on the current-limiting circuit 11.

Example four

As shown in Figure 6; On the basis of Fig. 2; This current-limiting circuit 11 comprises the adjustment pipe x that connects with collections of loads; The control end of this adjustment pipe x links to each other with the output of current control circuit 12 output current control signal Vgx, and realizes exchanging the control of homogeneous tube x operating state through this current controling signal Vgx.Be specially:

Adjustment pipe x connects with collections of loads A, and current control circuit 12 provides current controling signal Vgx; The electric current of current sampling circuit 13 sampling collections of loads A, the current signal that sampling is obtained outputs in the current control circuit 12; Current control circuit 12 is not less than at the current value of judging current signal; During promptly more than or equal to preset current-limiting points, control adjustment pipe x is operated in linear conducting state, and current value is big more; The conduction impedance of adjustment pipe x is big more, finally makes collections of loads A be operated in preset current-limiting points Ix place; When the current value of judging current signal during less than preset current-limiting points, the corresponding adjustment pipe x of control is operated in the saturation conduction state.

On the basis of the invention described above the disclosed embodiments one; Current control circuit 12 among Fig. 2 can be through the sample electric current of collections of loads A of series resistance on the total current loop; Also can be according to Kirchhoff's current law (KCL), obtain the current signal of collections of loads A through each the branch current signal stack of sampling respectively of series resistance on each current branch.That is to say that the current sampling circuit 13 among Fig. 2 can specifically be made up of following device or circuit.

Example five

When current sampling circuit 13 is second sampling resistor, can have one or morely, but the electric current sum of the electric current of one second sampling resistor of flowing through or a plurality of second sampling resistors needs to satisfy the requirement of the total current that equal collections of loads A.

As shown in Figure 7; On the basis of Fig. 2; Current sampling circuit 13 is for being series at one second sampling resistor Rs2 on the said load driving circuits total current loop; The end that this second sampling resistor connects direct voltage source 14 negative terminals is made as with reference to ground, and the other end connects the input of current control circuit 12.

Wherein, flow through the total current Io of the second sampling resistor Rs2 for each branch current sum.Therefore, current control circuit 12 can obtain the current signal of collections of loads A through the pressure drop of the second sampling resistor Rs2.

As shown in Figure 8, on the basis of Fig. 2, current sampling circuit 13 comprises two second sampling resistor Rs2 and Rs2 '.Wherein, one second sampling resistor Rs2 is connected on the current-limiting circuit 11 place branch roads, and another second sampling resistor Rs2 ' is connected on closing on the road of each height adjustment pipe place branch road.Current control circuit 12 is big or small through the current signal that the stack of the pressure drop on the second sampling resistor Rs2 and the Rs2 ' obtains collections of loads A, and the hot end of promptly said second sampling resistor Rs2 and Rs2 ' is connected the input of said current control circuit 12 respectively.

Need to prove; The quantity of second sampling resistor in the current sampling circuit 13 and the series position of each second sampling resistor are not limited to the Fig. 7 and the position of Fig. 8 in the example five, as long as satisfy the electric current that electric current sum that each second sampling resistor belongs to branch road can obtain collections of loads A.

On the basis of the invention described above Fig. 2 the disclosed embodiments one, can know; The control end of adjustment pipe 1 in the adjustment pipe set B～adjustment pipe n is by current control circuit 12 controls; It can comprise one or more control units also to have multiple structure for current control circuit 12; The control end of adjustment pipe 1 among Fig. 2～adjustment pipe n can independently be controlled by each control unit in the current control circuit 12, and the control end of perhaps any several adjustment pipes is controlled by a control unit jointly.

Wherein, When a plurality of adjustment pipes of the common control of control unit (the adjustment pipe x and the said son adjustment pipe that comprise 11 li of current-limiting circuits); The output of this control unit is serially connected with one or more reducing transformers, and said son is adjusted the control end of pipe and adjustment pipe x directly perhaps through being connected the output of this control unit behind one or more reducing transformers.

Need to prove, when any height adjustment pipe and/or adjustment pipe x are controlled by a control unit jointly, the preset current stabilization point arbitrarily that above-mentioned any height adjustment pipe and/or adjustment pipe x are corresponding or to preset current-limiting points equal.

Above-mentioned structure situation about current control circuit 12 specifically describes through following example.

Example six

Current control circuit 12 comprises: output is independent adjusts each control unit of the corresponding connection of control end of pipe with adjusting each height of managing in the set B, and two inputs of each said control unit connect the output and each reference signal of said current sampling circuit respectively.Specifically corresponding among Fig. 9 being:

Adjustment pipe 1, the control end of adjustment pipe 2 to adjustment pipe n be respectively by the control unit in the current control circuit 12 1, and control unit 2 is independently controlled to control unit n.

Wherein, control unit 1, control unit 2 connects reference signal Vref1 respectively to the first input end of control unit n, Vref2 to Vrefn, second input connects the output of current sampling circuit 13.The output signal Vs of current sampling circuit when said reference signal Vref1, Vref2 to Vrefn equal collections of loads A and be operated in corresponding preset current stabilization point.

For reference signal, in disclosed embodiment of this invention, comparatively preferred situation is to make Vref1＞Vref2......＞Vrefn; Promptly the adjustment pipe 1; The pairing preset current stabilization point I1 of adjustment pipe 2...... adjustment pipe n, I2......In reduces successively, if when the direct voltage that direct voltage source is exported descends always; Adjustment pipe 1, adjustment pipe 2...... adjustment pipe n conducting successively successively.

In this example, suppose when voltage ripple of power network, promptly during the dc voltage fluctuation after the rectification, make the electric current I o of collections of loads A descend always.

Wherein, when electric current I o reduces to less than preset current stabilization point I1, current sampling circuit 13 detect and the current signal Vs of output less than reference signal Vref1; At this moment, control unit 1 output Vg1 is to the control end of adjustment pipe 1, thereby control adjustment pipe 1 is operated in linear conducting state: and; Electric current I o is more little, and the conduction impedance of control unit 1 control adjustment pipe 1 is more little, and then adjustment pipe 1 place branch current is big more; Current-limiting circuit 11 place branch currents are more little; Pressure drop on the load subclass A1 is also more little, and the pressure drop on A～A1 load subclass is then big relatively more, finally makes collections of loads A electric current I o maintain preset current stabilization point I1 place; If electric current I o continues to reduce, the current signal Vs of current sampling circuit 13 outputs will reduce, and the output signal Vg1 of control unit 1 will increase, and at this moment, adjustment pipe 1 will be operated in saturation conduction and not play metering function, and the electric current I o of collections of loads A also can and then reduce.

When electric current I o reduced to less than preset current stabilization point I2, the variation of the operating state of adjustment pipe 2 was with the variation of the operating state of above-mentioned adjustment pipe 1.

Same, when Io reduced to less than In, the operating state of adjustment pipe n changed the description with above-mentioned adjustment pipe 1.

Therefore, along with the decline gradually of direct voltage, adjustment pipe 1, adjustment pipe 2...... adjustment pipe n conducting successively, the operating state of each adjustment pipe along with the decline of direct voltage successively by changing saturation conduction again into by the end of linear conducting.When a certain adjustment pipe had been operated in the saturation conduction state, when continuing to descend as if direct voltage, the next adjustment managed from by the end of the linear conducting of beginning, then when adjustment pipe n conducting, adjusts and manages 1, and n-1 saturation conduction is already managed in adjustment pipe 2...... adjustment.

Collections of loads is LED in embodiments of the present invention, along with adjustment pipe 1, and the conducting successively of adjustment pipe 2...... adjustment pipe n, load subclass A1, the LED among the A2......An is with deepening successively.

Example seven

Shown in figure 10, when current-limiting circuit during, compare with Fig. 9 for adjustment pipe x, increased a control unit in the current control circuit 12 among Figure 10, i.e. control unit x, the one of which end connects reference signal Vrefx, and the other end connects the output of current sampling circuit 13.

Wherein, the pairing preset current-limiting points of adjustment pipe x is labeled as Ix.As the electric current I o of collections of loads A during greater than preset current-limiting points Ix, control unit x output signal Vgx control adjustment pipe x is operated in linear conducting state.And the electric current I o of collections of loads A is big more, and Vgx is more little for control unit x output signal, and the impedance of adjustment pipe x is big more, and the pressure drop of adjustment pipe x is big more, and the pressure drop on the collections of loads A then reduces relatively, makes the electric current I o of collections of loads A be stabilized in preset current-limiting points Ix.If hypothesis Vrefx＞Vref1＞Vref2......＞Vrefn, at this moment, when promptly adjustment pipe x plays metering function, adjustment pipe 1, adjustment pipe 2... adjustment pipe n is operated in cut-off state.

Need to prove, the adjustment pipe 1 shown in Figure 10, identical in the operation principle of adjustment pipe 2...... adjustment pipe n and the above-mentioned example six, repeat no more here.

In addition, when current-limiting circuit 11 during for adjustment pipe x, the current control circuit 12 with a plurality of control units also can not increase control unit, only needs the control end of adjustment pipe x and the output that son adjustment pipe all is connected to former control unit to get final product.

Above-mentioned embodiment illustrated in fig. 2; And on the basis of the example of relevant current control circuit 12; When in current control circuit 12, having the situation of control unit control a plurality of son adjustment pipe and adjustment pipe x; Can also increase one or more reducing transformers, be that example describes with a control unit and a plurality of reducing transformer here.

Example eight

Shown in figure 11; Current control circuit 12 comprises: a control unit 121; The first input end of this control unit 121 connects reference signal Vref1, and second input connects the output of current sampling circuit 13, and the output of this control unit 121 then links to each other with the reducing transformer of series connection successively; The control end of adjusting each height adjustment pipe in the pipe set B is directly perhaps through being connected in the output of control unit 121 after one or more reducing transformers.Reducing transformer comprises the reducing transformer 1～reducing transformer (n-1) in the accompanying drawing 11, and the relation between the pipe of itself and adjustment in this example 1～adjustment pipe n is specially:

Adjustment pipe 1, the control end of adjustment pipe 2...... adjustment pipe n is all controlled by this control unit 121 jointly, adjustment pipe 1, the control end signal of adjustment pipe 2...... adjustment pipe n is labeled as Vg1, Vg2......Vgn successively.The first input end of control unit 121 connects reference signal Vref1, and second input connects the output of current sampling circuit 13, and the output of control unit 121 connects reducing transformer 1 successively, reducing transformer 2...... reducing transformer (n-1).The control end that is connected adjustment pipe 1 between the output of control unit 121 and the reducing transformer 1 connects the control end of adjustment pipe 2 through reducing transformer 1 back, connects the control end of adjustment pipe 3 through reducing transformer 2, and the like, connect the control end of adjustment pipe n through reducing transformer n-1.Therefore; Under the identical situation of the input of control unit 121, the control end signal Vg1＞Vg2 of adjustment pipe＞...＞Vgn can guarantee when power network fluctuation makes that the voltage of direct voltage source descends always; Adjustment pipe 1; Adjustment pipe 2...... adjustment pipe n conducting one by one, but because a shared control unit 121, each son adjustment pipe corresponding preset current stabilization point is identical.

Further, when control end signal Vg1 made adjustment pipe 1 be operated in linear conducting state, the too small adjustment pipe 2 that makes of control end signal Vg2 this moment ended, and promptly adjustment pipe 2 to adjustment pipe n also is in cut-off state; When control end signal Vg1 increase makes adjustment pipe 1 be operated in the saturation conduction state; Control end signal Vg2 also and then increases, and makes adjustment pipe 2 be operated in linear conducting state, at this moment; The too small adjustment pipe 3 that makes of control end signal Vg3 ends; By that analogy, can know adjustment pipe 1, adjustment pipe 2...... adjustment pipe n conducting one by one successively.

Shown in figure 12; When the current-limiting circuit in this load driving circuits is illustrated in figure 6 as adjustment pipe x; On the basis of Figure 11, increased a reducing transformer x in this current control unit 11; Promptly this current control unit 12 comprises: a control unit 121, and the first input end of this control unit 121 connects reference signal Vref1, and second input connects the output of current sampling circuit 13; The control end of each height adjustment pipe in the adjustment pipe set B is connected in the output of control unit 121 through one or more reducing transformers, and the control end of adjustment pipe x is connected between control unit 121 and first reducing transformer.Be specially: the output of control unit 121 connects the control end of adjustment pipe x, is connected to the control end of adjustment pipe 1 through reducing transformer x, and the connected mode of residue adjustment pipe 2...... adjustment pipe n is referring to like the corresponding description among Figure 11.

Need to prove; Any several adjustment pipe can a shared control unit; Be not limited to Figure 11 and shown in Figure 12 all adjustment pipe and all want a shared control unit 121; As long as the output end signal that satisfies shared control unit 121 after step-down step by step, inputs to the control end of the adjustment pipe that the load number of the load subclass of two ends serial connection increases successively respectively and get final product, can guarantee to adjust that to manage the load number that two ends are connected in series few more; When power network fluctuation made that the voltage of direct voltage source descends always, conducting was at first managed in this adjustment.

In addition; Shown in figure 13; If among adjustment pipe 1～adjustment pipe n arbitrarily or all by the 121 common controls of a control unit time, reducing transformer can be resistance drop depressor Rd, as comprising resistance drop depressor Rdx, resistance drop depressor Rd1～resistance drop depressor Rd (n-1) among Figure 13.Also be applicable to the reducing transformer among Figure 11, the reducing transformer of this moment then comprises resistance drop depressor Rd1～resistance drop depressor Rd (n-1).

Shown in figure 14, all right voltage-stabiliser tube of reducing transformer promptly comprises voltage-stabiliser tube reducing transformer TVx, voltage-stabiliser tube reducing transformer TV1～TV (n-1).Equally also be applicable to the reducing transformer among Figure 11.

Shown in figure 15, reducing transformer can also be diode, promptly comprises diode reducing transformer Dx, diode reducing transformer D1～D (n-1).Equally also be applicable to the reducing transformer among Figure 11.

Need to prove that above-mentioned resistance drop depressor, diode reducing transformer, voltage-stabiliser tube reducing transformer can mix use.As, the reducing transformer 1 of same control unit series connection can be the resistance drop depressor, and reducing transformer 2 can be the diode reducing transformer, and reducing transformer 3 then can be the voltage-stabiliser tube reducing transformer.

On the basis of Fig. 2 of the present invention, disclosed current control circuit 12, can know, can have one or more control units in the current control circuit 12.On the basis of the example of above-mentioned Fig. 2, Fig. 9, Figure 10, Figure 11 and Figure 12, example nine is the structure that example describes control unit there to be a control unit 121.

Example nine

Shown in Figure 16 a; This control unit 121 comprises: the inverting input of the second amplifier U2, this second amplifier U2 connects the output of current sampling circuit 13; In-phase input end connects reference signal Vref1; When this reference signal Vref1 presets current stabilization point for collections of loads A is operated in, the output signal of current sampling circuit 13.Need to prove that in this example, preset current-limiting points equates with all preset current stabilization points.Then be connected with compensating network 122 between the inverting input of this second amplifier U2 and the output.

Shown in Figure 16 b, when current sampling circuit 13 when being series at the second sampling resistor Rs2 on the load driving circuits total current loop, the end of this second sampling resistor Rs2 connects with reference to ground, i.e. the negative terminal of direct voltage source, the other end connects adjustment pipe set B.

This control unit 121 comprises the 3rd amplifier U3, and the inverting input of the 3rd amplifier U3 connects the second sampling resistor Rs2 and the common port of adjusting the pipe set B, and in-phase input end then connects reference signal Vref1.When the electric current I o of collections of loads A reduced, the pressure drop of the second sampling resistor Rs2 reduced, and the current potential of the inverting input of the 3rd amplifier U3 will reduce, and the output current potential of the 3rd amplifier U3 will increase.

Shown in Figure 16 c; When current sampling circuit 13 comprises: the second sampling resistor Rs2 that is series at current-limiting circuit 11 (adjustment pipe x) place branch road; And the second sampling resistor Rs2 that is series at the gathering in the loop of bypass (promptly be series in the adjustment pipe set B each said son adjustment pipe place branch road closing on the road), the position relation of two second sampling resistor Rs2 is shown in Figure 16 c.

Control unit 121 comprises: four high guaily unit U4; The inverting input of this four high guaily unit U4 is connected to the hot end of the second sampling resistor Rs2 ' respectively through second resistance R 2; Be connected to the hot end of the second sampling resistor Rs2 through the 3rd resistance R 3, make the electric current of the second sampling resistor Rs2 and Rs2 ' place branch road of inverting input sampling of four high guaily unit U4 equal the electric current I o of collections of loads A.Its operation principle is the same with Figure 16 b, repeats no more here.

Shown in Figure 16 d; When current sampling circuit 13 comprises: be series at the second sampling resistor Rs2 on the load driving circuits total current loop; The end of this second sampling resistor Rs2 connects the negative terminal of direct voltage source 14, and the other end connects current-limiting circuit 11, and this end is made as with reference to ground.

Control unit 121 comprises: the 5th amplifier U5, the in-phase input end of the 5th amplifier U5 connect reference signal Vref1 through the 4th resistance R 4 respectively, connect the negative terminal of direct voltage source 14 through the 5th resistance R 5; The inverting input of the 5th amplifier U5 connects with reference to ground, and is connected compensating network 122 between the inverting input of the 5th amplifier U5 and the in-phase input end.

The operation principle of this control unit 121 is the electric current I o of collections of loads A when reducing, and the current potential of the second sampling resistor Rs2 and R5 tie point raises, and then the current potential of the in-phase input end of four high guaily unit U4 raises, and the output end signal of four high guaily unit U4 increases.

Embodiment two

On the disclosed basis of the invention described above embodiment, because, when adjustment pipe 1; Adjustment pipe 2...... adjustment pipe n is successively one by one during the conducting shunting, load subclass A1, load subclass A2...... load subclass An deepening step by step; For the overall brightness of proof load set A constant; Need compensate for brightness step by step, therefore the invention also discloses the load driving circuits with compensate for brightness function, the concrete implementation of this embodiment two can be referring to following example.

Example ten

Shown in Figure 17; Compare with Fig. 2 and also to comprise current compensation circuit 15; Current compensation circuit 15 sample bypass total currents, when the bypass total current was non-vanishing, the electric current of the fractional load subclass of promptly flowing through was less than the electric current of collections of loads A; Current compensation circuit 15 increases said preset current stabilization point according to preset rules, promptly increases the pairing preset current stabilization point of each adjustment pipe through outputing signal to current control circuit 12.Based on the operation principle of current control circuit 12, if increase preset current stabilization point, it is in linear conducting state through control adjustment pipe, regulates the preset current stabilization point after the electric current I o that flows through collections of loads A is stabilized in increase.

When if this load is light fixture or LED, when the bypass total current was non-vanishing, the brightness of fractional load subclass reduced; Then the overall brightness of collections of loads A will descend to some extent, still, because the effect of current compensation circuit 15; Increased preset current stabilization point,, can increase the brightness of residual negative carrier set again through the regulating action of current control circuit 12; The overall brightness of collections of loads A is remained unchanged basically, thereby keep the efficient of load driving.

Example 11

Shown in figure 18; Control unit 121 first input ends connect reference signal Vref1 through the 6th resistance R g; Resistance (Rz1～Rzn) be connected in successively on the branch road of each said adjustment pipe 1 to adjustment pipe n place; And (hot end of Rz1～Rzn) is connected to the first input end of control unit 121 through resistance one to one (Rz1 '～Rzn ') to each said resistance, and second input of control unit 121 then connects the output of current sampling circuit 13.

The concrete course of work is: when voltage ripple of power network makes that the voltage of direct voltage source descends always; Along with adjustment pipe 1; Adjustment pipe 2...... adjustment pipe n conducting one by one successively; Need step by step compensate for brightness (promptly offset current) step by step thus realize that collections of loads A overall brightness is constant, the efficient that proof load drives.

For proof load set A overall brightness remains unchanged basically, make Rzn＞... Rz2＞Rz1.Because adjustment pipe 1, adjustment pipe 2...... adjustment pipe n is along with the decline conducting successively of direct voltage.When adjustment pipe 1 took the lead in conducting, the electric current of adjustment pipe 1 place branch road began to increase, and the brightness of load subclass A1 begins to descend; Then the pressure drop on the resistance R z1 begins to increase; Also raise the current potential of the first input end of control unit 121 through resistance R z1 ', and the first input end of control unit 121 is the reference signal input, through the regulating action of current control circuit 12; Thereby increase the electric current I o of collections of loads A; Increase the brightness of load subclass A-A1 thereupon, thereby collections of loads A overall brightness is remained unchanged, realize first order current compensation.

When 2 conductings of adjustment pipe, the electric current of adjustment pipe 2 place branch roads begins to increase, and the brightness of load subclass A2 begins to descend; Then the pressure drop on the resistance R z2 begins to increase; Owing to Rz2＞Rz1 and because first order current compensation has made electric current I o increase, the pressure drop on the Rz2 is at this moment then raised the current potential of the first input end of control unit 121 through resistance R z2 ' greater than the pressure drop on the resistance R z1 in the first order current compensation greatly; And the first input end of control unit 121 is the reference signal input; Through the regulating action of current control circuit 12, increase the electric current I o of collections of loads A to a greater extent, promptly increased the brightness of load subclass A-A2 greatly; Thereby collections of loads A overall brightness is remained unchanged, realize second level current compensation.

And the like, third level current compensation to the n level current compensation operation principle is with first order current compensation and second level current compensation.Here repeat no more.Through said process, can guarantee and improve the efficient of load driving.

Embodiment three

For each example among the foregoing description one and the embodiment two, each several part can mix the more concrete load driving circuits of formation each other, therefore, further describes and explains through following examples.

Shown in figure 19, current sampling circuit 13 is the second sampling resistor Rs2, and current-limiting circuit is metal-oxide-semiconductor (comprising that current-limiting circuit is Q1, adjustment pipe Q2～adjustment pipe Q (n-1)) with son adjustment pipe, and the reducing transformer that current control circuit is 12 li is a voltage-stabiliser tube.Need to prove; When 121 controls of Guan Youyi control unit of some adjustment; And when the adjustment pipe is metal-oxide-semiconductor, because metal-oxide-semiconductor is a voltage driven type, therefore; Also should be connected in series one the 7th resistance R 7 at last reducing transformer that is connected in series with between, offer the gate voltage discharge loop of metal-oxide-semiconductor with reference to ground.If a certain metal-oxide-semiconductor can not can be connected in series a resistance at the gate pole of this metal-oxide-semiconductor with between with reference to ground, for it provides discharge loop through this discharge loop discharge.And control unit 121 is concrete and Figure 16 a is similar; Comprise the second amplifier U2; In-phase input end connects reference signal Vref1; Inverting input is connected to the hot end of the second sampling resistor Rs2 through second resistance R 2, and inverting input and and output between then be connected with compensating network, wherein compensating network then is connected in series by the 8th resistance R 8 and first capacitor C 1 and forms.The negative electrode of the series arm that obtains after each voltage-stabiliser tube reducing transformer series connection connects the output of control unit 121, and the anode of said series arm connects with reference to ground through the 7th resistance R 7.Concrete operation principle is also similar with Figure 16 a, repeats no more here.

Shown in figure 20; Current sampling circuit 13 comprises two second sampling resistor Rs2; One second sampling resistor Rs2 is connected on the branch road of current-limiting circuit, and another second sampling resistor Rs2 ' is connected in all sons and adjusts closing on the road of pipe place branch roads, and current-limiting circuit is managed the triode that is connected resistance for base stage with sub-adjustment; The reducing transformer that current control circuit is 12 li is the resistance drop depressor, and control unit is then concrete identical with Figure 16 c.Concrete operation principle is also similar with Figure 16 c, repeats no more here.

Shown in figure 21; Current sampling circuit 13 is the second sampling resistor Rs2, and current-limiting circuit is metal-oxide-semiconductor with the adjustment pipe, and the tie point of the metal-oxide-semiconductor and the second sampling resistor Rs2 is with reference to ground; The reducing transformer that current control circuit is 12 li is a diode; The anode of the series arm that obtains after last reducing transformer and with reference to being connected with the 7th resistance R 7 between the ground, control unit is identical with Figure 16 d, diode reducing transformer are connected in series connects the output of control unit 121; The negative electrode of said series arm connects with reference to ground through the 7th resistance R 7, offers the gate voltage discharge loop of metal-oxide-semiconductor.If a certain metal-oxide-semiconductor can not can be connected in series a resistance at the gate pole of this metal-oxide-semiconductor with between with reference to ground, for it provides discharge loop through this discharge loop discharge.

The input of the auxiliary source of above-mentioned control unit can utilize the pressure drop of load subclass Ay to come power taking, and y >=n is counted in the load in the said fractional load subclass.When y=n, serial connection one voltage-stabiliser tube on last adjustment pipe place branch road in the set of adjustment pipe, when avoiding last adjustment to guarantee adequate food with conducting, the input terminal voltage of auxiliary source is too small.The internal circuit of auxiliary source is a known technology, such as three terminal regulator etc., repeats no more here.The reference signal of current control circuit also can be obtained by the output dividing potential drop of auxiliary source.

Need to prove; Above-mentioned said compensating network can comprise resistance and electric capacity; Said son adjustment pipe, adjustment pipe and current limiting tube can also can be triode for metal-oxide-semiconductor, and the control end of son adjustment pipe, adjustment pipe and current limiting tube is the base stage of the grid or the triode of metal-oxide-semiconductor.When said adjustment pipe was triode, the base stage of triode then need connect a resistance.

Embodiment four

In disclosed embodiment of this invention; Direct voltage source can directly be provided by external power supply; The direct voltage that also can behind over commutation (not comprising filter capacitor) or rectifying and wave-filtering (comprising filter capacitor), obtain for line voltage; The present invention does not limit this, and promptly the direct voltage of this direct voltage source output can also can be non-fluctuating direct voltage for the direct voltage of pulsation.

Need to prove,, think that promptly the direct voltage source of load driving circuits is provided by line voltage among this example or the embodiment if above-mentioned all examples or embodiment mention voltage ripple of power network in describing.

Shown in figure 22; Direct voltage Vin is rectifier bridge rectification and the process capacitor C 1 filtered direct voltage that electrical network is formed through diode D1, D2, D3, D4; Between the input of the output of electrical network and rectifier bridge, connect a capacitor C 2; Through the impedance dividing potential drop of capacitor C 2 and rectifier bridge DC side, can make the quantity configuration of LED lamp series connection more flexible

Because circuit of the present invention can be imported the direct voltage of pulsation, therefore, this load driving circuits can insert electrical network through rectifier bridge; Rectifier bridge is a dc pulse moving voltage with the ac sinusoidal voltage rectification of electrical network; Being directly inputted in the disclosed circuit of the embodiment of the invention (promptly on the basis of Figure 22, does not have filter capacitor C2) behind the rectifier bridge, through the effect of current-limiting circuit and bypass circuit; Input current waveform is near trapezoidal wave; Also promptly the power factor of this circuit is higher, and electromagnetic interference is low, and is little to the influence of electrical network.

Need to prove; When the direct voltage of importing is non-fluctuating direct voltage; When being the direct voltage of constant amplitude, when constant as if the amplitude of the constant DC voltage of importing, the state that the son adjustment in the set of adjustment pipe is managed can not change; When the magnitude of the constant DC voltage of importing, each height adjustment pipe can corresponding change.

In addition, except that direct voltage source or its realization circuit, the circuit of arbitrary portion or the circuit of any several parts can integrate, and are made into integrated chip among disclosed all embodiment of the invention described above.Preferably, to major general's current-limiting circuit, current sampling circuit, current control circuit, the adjustment pipe integrates, and is made into integrated chip; Perhaps above-mentioned integrated chip also is integrated with a load subclass arbitrarily, auxiliary source, any one among the current compensation circuit three or multiple; As will can integrate except that collections of loads A and components and parts and annexation thereof the direct voltage source (the realization circuit that comprises direct voltage source); Perhaps, with current-limiting circuit, current sampling circuit, current control circuit, the set of adjustment pipe, auxiliary source, the load subclass and the current compensation circuit that are connected in series between each height adjustment pipe two ends integrate, and process integrated chip.

In the accompanying drawing of the embodiment of the invention, be that example describes as load all with LED, in practical application, also can be other loads, thereby carry out the driving of load through load driving circuits of the present invention, do not limit here.

In sum:

The disclosed load driving circuits of the embodiment of the invention; Accomplish control through current-limiting circuit, current control circuit, current sampling circuit and the set of adjustment pipe to collections of loads electric current in the entire circuit; Effectively reduce current-limiting circuit and when voltage ripple of power network is big, carried out the loss of current limliting, realized improving the purpose of load driving efficient.

Each embodiment adopts the mode of going forward one by one to describe in this specification, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.

To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the present invention.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined General Principle can realize under the situation that does not break away from the spirit or scope of the present invention in other embodiments among this paper.Therefore, the present invention will can not be restricted to these embodiment shown in this paper, but will meet and principle disclosed herein and features of novelty the wideest corresponding to scope.

Claims

1. a load driving circuits is characterized in that, comprising:

2. circuit according to claim 1 is characterized in that, comprising: said preset current-limiting points is more than or equal to said preset current stabilization point.

3. circuit according to claim 1 is characterized in that, comprising: the said load subclass of connecting between each said son adjustment pipe two ends comprises the load of different numbers.

4. circuit according to claim 1 is characterized in that said current-limiting circuit comprises: current regulator diode.

5. circuit according to claim 1 is characterized in that, said current-limiting circuit comprises:

The current limiting tube of connecting with said collections of loads;

6. circuit according to claim 5 is characterized in that, said current-limiting control circuit comprises: first amplifier is connected in first sampling resistor in the branch road of current limiting tube place;

7. circuit according to claim 6; It is characterized in that; Said current-limiting control circuit also comprises: be connected in the compensating network between said first amplifier inverting input and the output, the inverting input of said first amplifier is connected to the hot end of said first sampling resistor through first resistance.

8. circuit according to claim 1 is characterized in that, said current-limiting circuit comprises: the adjustment pipe of connecting with said collections of loads, the control end of said adjustment pipe links to each other with the output of said current control circuit output current control signal.

9. according to any described circuit in the claim 1,5 or 8, it is characterized in that, each the height adjustment pipe in the said adjustment pipe set, the adjustment pipe in current limiting tube in the said current-limiting circuit or the said current-limiting circuit is triode or field effect metal-oxide-semiconductor.

10. according to any described circuit in the claim 1～8, it is characterized in that said current sampling circuit comprises: one or more second sampling resistors, the electric current sum of said second sampling resistor of flowing through equals the total current of collections of loads.

11. circuit according to claim 10; It is characterized in that; Comprise: be series at one second sampling resistor on the said load driving circuits total current loop, said second sampling resistor, one end connects with reference to ground, and the other end connects the input of said current control circuit;

12. according to any described circuit in the claim 1～7; It is characterized in that; Said current control circuit comprises: one or more control units; The corresponding control end that connects one or any said son adjustment pipe of the output of a said control unit, the first input end connection reference signal of said control unit, second input connects the output of said current sampling circuit.

13. circuit according to claim 12; It is characterized in that; When a plurality of said sons of the corresponding connection of output of a said control unit are adjusted the control end of pipe; Said current control circuit also comprises: be series at one or more reducing transformers of said control unit output, the control end of said son adjustment pipe is directly perhaps through being connected the output of said control unit behind one or more reducing transformers.

14. circuit according to claim 8 is characterized in that, when said current-limiting circuit was managed for adjustment, said current control circuit comprised:

15. circuit according to claim 14 is characterized in that, when the output correspondence of a said control unit connected a plurality of said son adjustment pipes and adjusts the control end of pipe, said current control circuit also comprised:

16., it is characterized in that said sub-reducing transformer comprises according to claim 13 or 15 described circuit: any one in voltage-stabiliser tube reducing transformer, diode reducing transformer or the resistance drop depressor or combination in any.

17. circuit according to claim 12; It is characterized in that; Said control unit comprises: the inverting input of second amplifier, said second amplifier connects the output of said current sampling circuit; In-phase input end connects reference signal, connects compensating network between the inverting input of said second amplifier and the output;

18. according to any said circuit in the claim 13～15; It is characterized in that; Said control unit comprises: the inverting input of second amplifier, said second amplifier connects the output of said current sampling circuit; In-phase input end connects reference signal, connects compensating network between the inverting input of said second amplifier and the output;

19. according to any described circuit in the claim 12～15; It is characterized in that; Said current sampling circuit comprises: be series at one second sampling resistor on the said load driving circuits total current loop; Said second sampling resistor, one end connects the negative terminal of direct voltage source, and the other end connects said current-limiting circuit and is made as with reference to ground;

20. circuit according to claim 16; It is characterized in that; Also comprise: auxiliary source; The input of said auxiliary source utilizes the pressure drop of a load subclass to come power taking and power supply to give said current control circuit, and the load number that said load subclass comprises is more than or equal to arbitrary sub load number of adjusting pipe two ends serial connection.

21. circuit according to claim 20 is characterized in that, when the maximum load that the load number that comprises when the said load subclass that is connected with said auxiliary source equals said son adjustment pipe two ends serial connection is counted, and series connection one voltage-stabiliser tube on this son adjustment pipe place branch road.

22. according to claim 20 or 21 described circuit, it is characterized in that, comprising: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit and said auxiliary source are an integrated circuit.

23. according to claim 20 or 21 described circuit, it is characterized in that, comprising: integrated said current-limiting circuit, the set of adjustment pipe, current control circuit, current sampling circuit, auxiliary source, and any one or more load subclass is combined into an integrated circuit.

24. according to claim 20 or 21 described circuit, it is characterized in that, also comprise:

25. circuit according to claim 24 is characterized in that, said current control unit includes only a control unit;

26. according to claim 24 or 25 described circuit; It is characterized in that; Comprise: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit, said auxiliary source and said current compensation circuit are an integrated circuit.

27. according to claim 24 or 25 described circuit; It is characterized in that; Comprise: integrated said current-limiting circuit, the set of said adjustment pipe, said current control circuit, said current sampling circuit, said auxiliary source, said current compensation circuit and any one or more said load subclass are combined into an integrated circuit.

28., it is characterized in that the input of said load driving circuits inserts electrical network through rectifier bridge according to any described circuit in the claim 1～8,11,13,14,15,17,20,21,25.

29. circuit according to claim 28 is characterized in that, the output of rectifier bridge is parallel with filter capacitor, and the input of rectifier bridge is in series with dividing potential drop electric capacity.