CN104394635A - LED driver - Google Patents
LED driver Download PDFInfo
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- CN104394635A CN104394635A CN201410729323.4A CN201410729323A CN104394635A CN 104394635 A CN104394635 A CN 104394635A CN 201410729323 A CN201410729323 A CN 201410729323A CN 104394635 A CN104394635 A CN 104394635A
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Abstract
The application provides a LED driver. A LED load is driven by connecting an AC-DC converting circuit in series with a DC-DC converting circuit; a current control loop detects the current passing through the LED load, and controls a main switch tube of the DC-DC converting circuit to make the LED driver output a constant current; a voltage control loop detects a signal representing the output voltage of the AC-DC converting circuit or the DC-DC converting circuit, and compares the signal with a benchmark value, controls the main switch tube of the AC-DC converting circuit based on the comparison result in order to make the output voltage of the AC-DC converting circuit be less than the LED load voltage. By such connection manner and control manner, the response speed of the voltage control loop can be designed slower in order to ensure a higher PF value and achieve a PFC function, therefore the response speed of the current control loop can be designed faster in order to ensure that the output current of the LED driver has less ripple, thereby avoiding the occurrence of stroboflash in the LED load.
Description
Technical field
The present invention relates to LED Driving technique field, particularly relate to a kind of LED driver.
Background technology
LED, as a kind of novel illumination device, because its luminous efficiency is high, be widely used in lighting field, and it needs constant current to drive usually, the LED driver driven as its constant current in the prior art often adopts single-stage solution.
And adopt the LED driver of single-stage solution, because PFC (Power FactorCorrection taken into account by needs, power factor correction) function, namely its control loop needs very slow response speed just can have higher PF (Power Factor, power factor) value, therefore, its control loop response speed is slower, and this can cause output current to have larger ripple, this line is the half in input ac voltage cycle wave period.When LED driver connects load, this current ripples will cause LED to occur stroboscopic phenomenon, and this stroboscopic phenomenon will affect the useful life of LED, also have certain damage to human eye.
Summary of the invention
In view of this, the invention provides a kind of LED driver, there is larger ripple to solve prior art output current and cause LED to occur the problem of stroboscopic phenomenon.
To achieve these goals, the technical scheme that provides of the embodiment of the present invention is as follows:
A kind of LED driver, comprising:
The AC-DC translation circuit of output series connection and DC-DC conversion circuit, described AC-DC translation circuit and DC-DC conversion circuit are jointly for driving LED load;
The current regulator that output is connected with the control end of main switch in described DC-DC conversion circuit, for detecting the electric current flowing through described LED load, and controlling the main switch of described DC-DC conversion circuit, making described LED driver constant current output;
The voltage control loop that output is connected with the control end of main switch in described AC-DC translation circuit, for detecting the signal of the output voltage characterizing described AC-DC translation circuit and/or described DC-DC conversion circuit, and compare with fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, the response speed of described current regulator is greater than the response speed of described voltage control loop.
Preferably, the input of described current regulator, is connected on the output loop of described DC-DC conversion circuit by sampling resistor.
Preferably, described voltage control loop is for detecting the signal of the output voltage characterizing described AC-DC translation circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, described voltage control loop is for detecting the signal of the output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, described voltage control loop characterizes the signal of output voltage of described AC-DC translation circuit and the difference of the output voltage of described DC-DC conversion circuit for detecting, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, described voltage control loop is for the output voltage that detects described AC-DC translation circuit and the difference of signal of output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, described voltage control loop is for the signal that detects the output voltage characterizing described AC-DC translation circuit and the difference of signal of output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
Preferably, the described fiducial value in described voltage control loop is the value preset according to described LED load voltage.
Preferably, the described fiducial value in described voltage control loop is described LED load voltage.
Preferably, also comprise: the constant pressure source be connected with the input of described DC-DC conversion circuit.
Preferably, described AC-DC translation circuit is isolated form topology, and the first vice-side winding in described AC-DC translation circuit is connected with the first rectification module, and the output of described first rectification module is as the output of described AC-DC translation circuit; The second vice-side winding in described AC-DC translation circuit is connected with the second rectification module, and the output of described second rectification module is connected with the input of described DC-DC conversion circuit.
Preferably, described DC-DC conversion circuit is non-isolation type topology.
Preferably, the main switch in described DC-DC conversion circuit and described current regulator are arranged in same integrated circuit.
The application provides a kind of LED driver, driving LED load after being connected with DC-DC conversion circuit by AC-DC translation circuit; Detected the electric current flowing through described LED load by current regulator, and control the main switch of described DC-DC conversion circuit, make described LED driver constant current output; The signal of the output voltage characterizing described AC-DC translation circuit and/or described DC-DC conversion circuit is detected by voltage control loop, and compare with fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.The described LED driver that the application provides, by above-mentioned connected mode and control mode, the response speed of described voltage control loop can be designed slower, to ensure higher PF value, realize PFC function, therefore the response speed of described current regulator can design comparatively fast, ensures the output current low ripple of described LED driver, avoids LED load to occur stroboscopic phenomenon.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the accompanying drawing provided.
A kind of LED driver circuit figure that Fig. 1 provides for the embodiment of the present application;
A kind of LED driver circuit figure that Fig. 2 provides for another embodiment of the application;
A kind of LED driver circuit figure that Fig. 3 provides for another embodiment of the application.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Embodiments provide a kind of LED driver, there is larger ripple to solve prior art output current and cause LED to occur the problem of stroboscopic phenomenon.
Concrete, as shown in Figure 1, described LED driver comprises:
The AC-DC translation circuit 101 of output series connection and DC-DC conversion circuit 102;
The current regulator 103 that output is connected with the control end of main switch in DC-DC conversion circuit 102;
The voltage control loop 104 that output is connected with the control end of main switch in AC-DC translation circuit 101.
What deserves to be explained is, in Fig. 1, the high-voltage output end of AC-DC translation circuit 101 is connected with the positive pole of LED load, and the low-voltage output of DC-DC conversion circuit 102 is connected with the negative pole of described LED load; In actual applications, the high-voltage output end of DC-DC conversion circuit 102 also can be adopted to be connected with the positive pole of LED load, and the low-voltage output of AC-DC translation circuit 101 is connected with the negative pole of described LED load; Fig. 1 is only a kind of example, and the connected mode of AC-DC translation circuit 101 and DC-DC conversion circuit 102 and described LED load is also not specifically limited, and can determine according to the applied environment of its reality.
Concrete operation principle is:
In prior art, in order to avoid output current, there is larger ripple and the stroboscopic phenomenon causing LED to occur, the LED driver of two-step scheme is adopted also to be selected by more, the input of its rear class DC-DC converter is directly connected with the output of prime AC-DC converter, described prime AC-DC converter is used for realizing PFC function, described rear class DC-DC converter is used for realizing constant current or pressure-keeping functions, the control loop response speed of prime AC-DC converter can be very slow, and LED driver output current ripple problem can not be caused, the control loop response speed of rear class DC-DC converter can be very fast, meet rapid adjustment and reduce output current ripple demand, solve single-stage solution Problems existing easily.
But two-step scheme has carried out two times transfer due to input power, the efficiency of LED driver has been made to be the efficiency product of two-stage circuit.Such as front stage circuits efficiency is η 1, and late-class circuit efficiency is η 2, then prior art adopts the efficiency eta=η 1* η 2 of the LED driver of two-step scheme, greatly reduces the efficiency of LED driver, increases loss, can not highlight the advantage that LED illumination System is energy-conservation.
And the LED driver adopting the present embodiment to provide, AC-DC translation circuit 101 drives described LED load after connecting with DC-DC conversion circuit 102 jointly; Current regulator 103 detects the electric current flowing through described LED load, and controls the main switch of DC-DC conversion circuit 102, makes described LED driver constant current output; Voltage control loop 104 detects the signal of the output voltage characterizing AC-DC translation circuit 101 and/or DC-DC conversion circuit 102, and compare with fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage, ensure that DC-DC conversion circuit 102 can work; By above-mentioned connected mode and control mode, the response speed of voltage control loop 104 can design slower, to ensure higher PF value, realize PFC function, make the response speed of current regulator 103 can design comparatively fast thus, ensure the output current low ripple of described LED driver, avoid described LED load to occur stroboscopic phenomenon.Simultaneously, if the efficiency of AC-DC translation circuit 101 is η 1, the efficiency of DC-DC conversion circuit 102 is η 2, then the efficiency eta of described LED driver is only slightly less than η 1, the degree that the efficiency eta of described LED driver is less than η 1 depends on the size of DC-DC conversion circuit 102 processing power, adopts that the LED driver efficiency of two-step scheme is high and loss is low compared to existing technology.
The LED driver that the present embodiment provides, because AC-DC translation circuit 101 output is connected with DC-DC conversion circuit 102 output and is connected described LED load, therefore, current regulator 103 detects the electric current flowing through described LED load, can by detecting the electric current of DC-DC conversion circuit 102 output loop, or the electric current of AC-DC translation circuit 101 output loop realizes, the electric current of any point of sampling series loop, all with load current equivalence or identical, Fig. 1 is only a kind of example, is not specifically limited herein.
What deserves to be explained is, there is in prior art the LED driver of Voltage loop, this Voltage loop detects LED driver output voltage, and comparing according to testing result and reference voltage, control the switching tube of the translation circuit in LED driver, make the output voltage of LED driver be the voltage under reference voltage setting.And the described LED driver that the present embodiment provides, what voltage control loop 104 detected is not the output voltage of described LED driver, also the voltage that described LED driver output voltage is the setting of a certain reference voltage can not be controlled, but detect the output voltage V1 of AC-DC the translation circuit 101 and/or output voltage V2 of DC-DC conversion circuit 102, specifically comprise: the output voltage V1 of AC-DC translation circuit 101, the output voltage V2 of DC-DC conversion circuit 102, the difference V1-V2 of the output voltage V1 of AC-DC translation circuit 101 and the output voltage V2 of DC-DC conversion circuit 102, characterize the signal K*V1 of output voltage V1 of AC-DC the translation circuit 101 and difference K*V1-V2 of the output voltage V2 of DC-DC conversion circuit 102, the output voltage V1 of AC-DC the translation circuit 101 and difference V1-K*V2 of the signal K*V2 of the output voltage V2 of sign DC-DC conversion circuit 102, or characterize the signal K1*V1 of the output voltage V1 of AC-DC translation circuit 101 and the difference K1*V1-K2*V2 of the signal K2*V2 of the output voltage V2 of sign DC-DC conversion circuit 102, compare with fiducial value again, according to comparative result control AC-DC translation circuit 101, the output voltage V1 of AC-DC translation circuit 101 is made to be less than the voltage of described LED load, the output voltage of DC-DC conversion circuit 102 is made to be forced zero, to ensure that DC-DC conversion circuit 102 can normal closed loop work, meanwhile, when the change in voltage of described LED load, the output voltage V1 of AC-DC the translation circuit 101 and/or output voltage V2 of DC-DC conversion circuit 102 changes thereupon, makes described LED driver output voltage dynamically can follow the tracks of described LED load voltage, be not that to control the output voltage of LED driver as in the prior art constant, therefore, the described LED driver that the present embodiment passes through is the load being applicable to wide region, namely when the LED load of different loads voltage is connected to the described LED driver of the present embodiment, described LED driver can export suitable voltage automatically, drives this LED load work.
Preferably, the response speed of current regulator 103 is greater than the response speed of voltage control loop 104.
The described LED driver that the present embodiment provides, the response speed design of voltage control loop 104 comparatively slow, can ensure higher PF value, realize PFC function; What now the response speed of current regulator 103 can design is very fast, ensures the output current low ripple of described LED driver, avoids described LED load to occur stroboscopic phenomenon.
Preferably, the input of current regulator 103 is connected on the output loop of DC-DC conversion circuit 102 by sampling resistor.
It should be noted that, because the output of AC-DC translation circuit 101 and DC-DC conversion circuit 102 is cascaded, therefore, current regulator 103 is when detecting load current, can the electric current of any point in measure loop, the electric current of any point is all identical with the load current of series loop; The present embodiment as shown in Figure 1, have selected the negative pole of described LED load, is only a kind of example, but is not limited thereto, in embody rule, and can depending on applied environment.
Preferably, voltage control loop 104 is for detecting the signal of the output voltage V2 characterizing DC-DC conversion circuit 102, as K*V2, and compare with described fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
In the present embodiment, the feedback signal inputted due to voltage control loop 104 is K*V2, and also namely voltage control loop 104 controls the business that DC-DC conversion circuit 102 output voltage V2 is described fiducial value and K.Because fiducial value is non-vanishing, the output voltage V2 of DC-DC conversion circuit 102 is non-vanishing, makes the output voltage V1 of AC-DC translation circuit lower than described LED load voltage.When this fiducial value is constant, the output voltage V2 of DC-DC conversion circuit 102 is constant, and when described LED load voltage raises, the output voltage V1 of AC-DC translation circuit 101 increases, and vice versa.Therefore, voltage control loop 104 control AC-DC translation circuit 101, makes the output voltage V1 of AC-DC translation circuit 101 change with described LED load change in voltage, the output voltage of described LED driver finally can be made dynamically to follow the tracks of described LED load voltage.
Preferably, voltage control loop 104 is for detecting the signal of the output voltage V1 characterizing AC-DC translation circuit 101 (as K*V1, K is the proportionality coefficient obtained according to the parameter of components and parts in circuit system), and compare with described fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
In the present embodiment, the feedback signal inputted due to voltage control loop 104 is K*V1, and also namely voltage control loop 104 control AC-DC translation circuit 101 output voltage V1 is the business of described fiducial value and K.Preferably, when the amplitude of this fiducial value is along with described LED load voltage monotonic increase, when described LED load voltage raises, the output voltage V1 of AC-DC translation circuit 101 increases, and vice versa.Therefore, voltage control loop 104 control AC-DC translation circuit 101, makes the output voltage V1 of AC-DC translation circuit 101 change with described LED load change in voltage, the output voltage of LED driver finally can be made dynamically to follow the tracks of described LED load voltage.
Preferably, voltage control loop 104 is for detecting the signal (as K*V1) of output voltage V1 and the difference of the output voltage V2 of DC-DC conversion circuit 102 that characterize AC-DC translation circuit 101, i.e. K*V1-V2, and compare with described fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
In the present embodiment, the feedback signal inputted due to voltage control loop 104 is K*V1-V2, also namely voltage control loop 104 control the signal K*V1 of the output voltage V1 characterizing AC-DC translation circuit 101 and DC-DC conversion circuit 102 output voltage V2 difference be fiducial value Vref because following equation can be released:
K*V1-V2＝Vref (1)
Wherein, Vo is described LED load voltage, the i.e. output voltage of described LED driver to V1+V2=Vo (2).
Can be drawn by equation (1) and (2):
V1＝(Vo+Vref)/(K+1)
V2＝(K*Vo-Vref)/(K+1)
Above formula demonstrates the relation of the output voltage V1 of AC-DC translation circuit 101 and the output voltage Vo (i.e. described LED load voltage) of DC-DC conversion circuit 102 output voltage V2 and described LED driver.
What deserves to be explained is, fiducial value Vref can be fixed value, and when described LED load voltage raises, the output voltage V1 of AC-DC translation circuit 101 increases, and the output voltage V2 of DC-DC conversion circuit 102 increases, and vice versa.Therefore, voltage control loop 104 control AC-DC translation circuit 101, the output voltage of AC-DC translation circuit 101 and DC-DC conversion circuit 102 is all changed with described LED load change in voltage, the output voltage of described LED driver finally can be made dynamically to follow the tracks of described LED load voltage.
Preferably, this fiducial value Vref can also with described LED load voltage monotonic increase; Like this, when described LED load voltage raises, this fiducial value Vref also raises, the output voltage V1 of AC-DC translation circuit 101 increases, but the speed that the output voltage V2 of DC-DC conversion circuit 102 raises with load voltage is slow when comparatively fiducial value Vref is fixed value, or the output voltage V2 of DC-DC conversion circuit 102 is constant, and vice versa.
Preferably, voltage control loop 104 is for detecting the output voltage V1 of AC-DC translation circuit 101, with the difference of the signal (as K*V2) of the output voltage V2 of sign DC-DC conversion circuit 102, i.e. V1-K*V2, and compare with described fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
Preferably, voltage control loop 104 is for the signal K1*V1 that detects the output voltage V1 characterizing AC-DC translation circuit 101 and the difference K1*V1-K2*V2 of signal K2*V2 of output voltage V2 characterizing DC-DC conversion circuit 102, and compare with described fiducial value, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
Concrete principle is same as the previously described embodiments, repeats no more herein.
What deserves to be explained is, shown in Fig. 1, the input of voltage control loop 104 is connected with the output of DC-DC conversion circuit 102, is a kind of example, and now the input variable of voltage control loop 104 is the output voltage V2 of DC-DC conversion circuit 102.
Above-described embodiment lists the value that voltage control loop 104 can detect to be had: the signal K*V1 characterizing the output voltage V1 of AC-DC translation circuit 101, characterize the signal K*V2 of the output voltage V2 of DC-DC conversion circuit 102, characterize the signal K*V1 of output voltage V1 of AC-DC the translation circuit 101 and difference K*V1-V2 of the output voltage V2 of DC-DC conversion circuit 102, the output voltage V1 of AC-DC the translation circuit 101 and difference V1-K*V2 of the signal K*V2 of the output voltage V2 of sign DC-DC conversion circuit 102, or characterize the signal K1*V1 of the output voltage V1 of AC-DC translation circuit 101 and the difference K1*V1-K2*V2 of the signal K2*V2 of the output voltage V2 of sign DC-DC conversion circuit 102, when K is 1, that is to say the output voltage V1 of AC-DC translation circuit 101, the output voltage V2 of DC-DC conversion circuit 102, or the difference V1-V2 of the output voltage V1 of AC-DC translation circuit 101 and the output voltage V2 of DC-DC conversion circuit 102, then detected value and corresponding described fiducial value are compared, according to the main switch of comparative result control AC-DC translation circuit 101, make the output voltage of AC-DC translation circuit 101 lower than described LED load voltage.
Such as, when voltage control loop 104 detects the output voltage V1 of AC-DC translation circuit 101, if the output voltage V1 of AC-DC translation circuit 101 equals the voltage of described LED load, then the output voltage V2 of DC-DC conversion circuit 102 equals zero, sampled value in voltage control loop 104 is greater than fiducial value, voltage control loop 104 is by the main switch of control AC-DC translation circuit 101, its output voltage V1 is reduced, because the voltage of described LED load is constant under same state, the output voltage V1 of AC-DC translation circuit 101 reduces will make the output voltage V2 of DC-DC conversion circuit 102 raise, circulation regulates until the output voltage V2 of DC-DC conversion circuit 102 is increased to fiducial value, this ensure that the output voltage V1 of AC-DC translation circuit 101 is less than load voltage.
When voltage control loop 104 detects the output voltage V2 of DC-DC conversion circuit 102, if the output voltage V2 of DC-DC conversion circuit 102 is close to zero, sampled value in voltage control loop 104 is less than fiducial value, voltage control loop 104 is by the main switch of control AC-DC translation circuit 101, its output voltage V1 is reduced, because the voltage of described LED load is constant under same state, the output voltage V1 of AC-DC translation circuit 101 reduces will make the output voltage V2 of DC-DC conversion circuit 102 raise, circulation regulates until the output voltage V2 of DC-DC conversion circuit 102 is increased to fiducial value, this ensure that the output voltage V1 of AC-DC translation circuit 101 is less than load voltage.
When voltage control loop 104 detects the difference V1-V2 of the output voltage V1 of AC-DC translation circuit 101 and the output voltage V2 of DC-DC conversion circuit 102, if the output voltage V1 of AC-DC translation circuit 101 equals the voltage of described LED load, then the output voltage V2 of DC-DC conversion circuit 102 equals zero, V1-V2=V1, in voltage control loop 104, the fiducial value of design must be less than current sample values V1-V2, voltage control loop 104 is by the main switch of control AC-DC translation circuit 101, its output voltage V1 is reduced, because load voltage is constant under same state, the output voltage V1 of AC-DC translation circuit 101 reduces will make the output voltage V2 of DC-DC conversion circuit 102 raise, circulation regulates until the output voltage V2 of DC-DC conversion circuit 102 is increased to fiducial value, this ensure that the output voltage V1 of AC-DC translation circuit 101 is less than load voltage.
Above-mentioned three kinds of voltage detecting modes, all can ensure that the output voltage V1 of AC-DC translation circuit 101 is less than the voltage of described LED load, can also ensure that described LED driver is applicable to the load of wide region simultaneously.
The signal that voltage control loop 104 specifically detects can be determined according to concrete applicable cases, is not specifically limited herein.Such as, voltage control loop 104 detects V1-V2 and can also replace with detecting K*V1-V2, and its operation principle (i.e. regulable control mode) is identical with detection V1-V2, repeats no longer one by one herein.
Preferably, the described fiducial value in voltage control loop 104 is the value preset according to described LED load voltage.
Preferably, the described fiducial value in voltage control loop 104 is described LED load voltage.
Described fiducial value can carry out presetting or adopting described LED load voltage according to described LED load voltage, now voltage control loop 104 is by the main switch of control AC-DC translation circuit 101, can raise, reduces with the reduction of load voltage by control AC-DC translation circuit 101 output voltage V1 along with the rising of described LED load voltage.Because the processing power ratio of AC-DC translation circuit 101 is higher, the efficiency of whole LED driver is also higher, when the output voltage V1 of AC-DC translation circuit 101 raises along with the rising of described LED load voltage, its power exported also raises along with the rising of bearing power, can ensure that the power of LED driver in the load voltage of wide range all maintains a higher level.
Preferably, as shown in Figure 2, described LED driver also comprises: the constant pressure source Vs be connected with the input of DC-DC conversion circuit 102.
Adopt constant pressure source Vs to be connected with DC-DC conversion circuit 102, then the voltage constant of DC-DC conversion circuit 102 reception is constant.
Preferably, as shown in Figure 3, AC-DC translation circuit 101 is isolated form topology, and the first vice-side winding 111 in AC-DC translation circuit 101 is connected with the first rectification module 112, and the output of the first rectification module 112 is as the output of AC-DC translation circuit 101; The second vice-side winding 113 in AC-DC translation circuit 101 is connected with the second rectification module 114, and the output of the second rectification module 114 is connected with the input of DC-DC conversion circuit 102.
Preferably, as shown in Figure 3, the input of voltage control loop 104 is connected with the input of DC-DC conversion circuit 102 and output respectively.
When AC-DC translation circuit 101 is isolated form topology, the input voltage Vs of DC-DC conversion circuit 102 adopts the output voltage of AC-DC translation circuit 101 second rectification module 114, now the output voltage of the first rectification module 112 and the second rectification module 114 is proportional, then the input voltage Vs of DC-DC conversion circuit 102 also becomes this ratio, as Vs/V1=K with the output voltage V1 of AC-DC translation circuit 101; If when now voltage control loop 104 wants to design the difference V1-V2 becoming and detect the output voltage V1 of AC-DC translation circuit 101 and the output voltage V2 of DC-DC conversion circuit 102, also by detecting input voltage Vs and the output voltage V2 of DC-DC conversion circuit 102, K*V1-V2 can be obtained; The input of voltage control loop 104 is connected with output with the input of DC-DC conversion circuit 102 respectively so also can be designed as.
Preferably, described DC-DC conversion circuit is non-isolation type topology.
When described DC-DC conversion circuit is non-isolation type topology, the input of described voltage control loop also can be connected with the low pressure input of DC-DC conversion circuit 102 and low-voltage output.
Preferably, the main switch in described DC-DC conversion circuit and described current regulator are arranged in same integrated circuit.
The integration section of described DC-DC conversion circuit and described current regulator, can determine according to concrete applicable cases, be not specifically limited herein.
In the present invention, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.For device disclosed in embodiment, because it corresponds to the method disclosed in Example, so description is fairly simple, relevant part illustrates see method part.
Below be only the preferred embodiment of the present invention, those skilled in the art understood or realizes the present invention.To be apparent to one skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (14)
1. a LED driver, is characterized in that, comprising:
The AC-DC translation circuit of output series connection and DC-DC conversion circuit, described AC-DC translation circuit and DC-DC conversion circuit are jointly for driving LED load;
The current regulator that output is connected with the control end of main switch in described DC-DC conversion circuit, for detecting the electric current flowing through described LED load, and controlling the main switch of described DC-DC conversion circuit, making described LED driver constant current output;
The voltage control loop that output is connected with the control end of main switch in described AC-DC translation circuit, for detecting the signal of the output voltage characterizing described AC-DC translation circuit and/or described DC-DC conversion circuit, and compare with fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
2. LED driver according to claim 1, is characterized in that, the response speed of described current regulator is greater than the response speed of described voltage control loop.
3. LED driver according to claim 1, is characterized in that, the input of described current regulator, is connected on the output loop of described DC-DC conversion circuit by sampling resistor.
4. LED driver according to claim 1, it is characterized in that, described voltage control loop is for detecting the signal of the output voltage characterizing described AC-DC translation circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
5. LED driver according to claim 1, it is characterized in that, described voltage control loop is for detecting the signal of the output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
6. LED driver according to claim 1, it is characterized in that, described voltage control loop characterizes the signal of output voltage of described AC-DC translation circuit and the difference of the output voltage of described DC-DC conversion circuit for detecting, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
7. LED driver according to claim 1, it is characterized in that, described voltage control loop is for the output voltage that detects described AC-DC translation circuit and the difference of signal of output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
8. LED driver according to claim 1, it is characterized in that, described voltage control loop is for the signal that detects the output voltage characterizing described AC-DC translation circuit and the difference of signal of output voltage characterizing described DC-DC conversion circuit, and compare with described fiducial value, control the main switch of described AC-DC translation circuit according to comparative result, make the output voltage of described AC-DC translation circuit lower than described LED load voltage.
9. LED driver according to claim 1, is characterized in that, the described fiducial value in described voltage control loop is the value preset according to described LED load voltage.
10. LED driver according to claim 1, is characterized in that, the described fiducial value in described voltage control loop is described LED load voltage.
11. LED drivers according to claim 1, is characterized in that, also comprise: the constant pressure source be connected with the input of described DC-DC conversion circuit.
12. LED drivers according to claim 1, it is characterized in that, described AC-DC translation circuit is isolated form topology, the first vice-side winding in described AC-DC translation circuit is connected with the first rectification module, and the output of described first rectification module is as the output of described AC-DC translation circuit; The second vice-side winding in described AC-DC translation circuit is connected with the second rectification module, and the output of described second rectification module is connected with the input of described DC-DC conversion circuit.
13. LED drivers according to claim 1, is characterized in that, described DC-DC conversion circuit is non-isolation type topology.
14. LED drivers according to claim 1, is characterized in that, the main switch in described DC-DC conversion circuit and described current regulator are arranged in same integrated circuit.
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| CN201410729323.4A CN104394635B (en) | 2014-12-04 | 2014-12-04 | A kind of LED driver |
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| CN201410729323.4A CN104394635B (en) | 2014-12-04 | 2014-12-04 | A kind of LED driver |
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| CN104394635A true CN104394635A (en) | 2015-03-04 |
| CN104394635B CN104394635B (en) | 2017-06-13 |
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| CN105187749A (en) * | 2015-09-25 | 2015-12-23 | 深圳创维－Rgb电子有限公司 | Television backlight driving device and driving method thereof |
| CN108811257A (en) * | 2018-08-07 | 2018-11-13 | 四维生态科技（杭州）有限公司 | A kind of control method of LED illumination System and LED load circuit |
| CN114867155A (en) * | 2021-01-20 | 2022-08-05 | 英飞特电子（杭州）股份有限公司 | LED driving power supply and efficiency adjusting method thereof |
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| CN202424506U (en) * | 2012-01-11 | 2012-09-05 | 西南交通大学 | Single-stage high power factor correction converter with low output power frequency ripple wave |
| CN204272450U (en) * | 2014-12-04 | 2015-04-15 | 英飞特电子（杭州）股份有限公司 | A kind of LED driver |
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| CN114867155A (en) * | 2021-01-20 | 2022-08-05 | 英飞特电子（杭州）股份有限公司 | LED driving power supply and efficiency adjusting method thereof |
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|---|---|
| CN104394635B (en) | 2017-06-13 |
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