WO2020151101A1

WO2020151101A1 - Dual voltage linear led load matching circuit

Info

Publication number: WO2020151101A1
Application number: PCT/CN2019/083214
Authority: WO
Inventors: 陶冬毅; 刘明龙
Original assignee: 苏州菲达旭微电子有限公司
Priority date: 2019-01-21
Filing date: 2019-04-18
Publication date: 2020-07-30
Also published as: CN109618467A

Abstract

A dual voltage linear LED load matching circuit comprises five loads (11 to 15), a switch circuit (2), and three control units (3 to 5), wherein one or more of a third load (13), a fourth load (14), and a fifth load (15) can be short-circuited. A first load (11), the fifth load (15), and a third control unit (5) are connected in series to form a first branch. The fourth load (14), a second control unit (4), and a second load (12) are connected in series to form a second branch. The first branch and the second branch are connected in parallel at two ends of an input voltage source. One end of the third load (13) is connected to the second control unit (4) by means of a first control unit (3). The other end of the third load (13) is connected to one end of the switch circuit (2). An intermediate connection end between the first control unit (3) and the fifth load (15) is connected to the other end of the switch circuit (2). The load matching circuit switches between different topologies according to operation scenarios of a first rated operating voltage (V1) and a second rated operating voltage (V2), thereby achieving load matching for two voltages.

Description

A linear LED load matching circuit under dual voltage

Technical field

The invention relates to the field of dual-voltage load matching, in particular to a linear LED load matching circuit under dual-voltage.

Background technique

As an efficient new light source, LED is widely used in various fields of lighting due to its long life, low energy consumption, energy saving and environmental protection. For LED loads, the input voltage range is narrow, and can only be used under a single 220V, 110V, or 230V AC grid voltage, or a fixed battery voltage, such as 12V or 24V, must be used.

In the lighting industry, there are many LED lighting devices in the manufacturing process, and it is impossible to determine which country or region in the world the device will ultimately be used in, and the voltage standards of each country are different. For example, Japan uses 110V AC, China Using 220V AC power, Europe uses 230V AC power, etc., so it is very necessary to be able to meet the LED load matching circuit of the two power grids.

At present, the existing linear constant current drive dual voltage solutions on the market mostly adopt the mode of controlling two light strings separately. The system architecture is complicated, the peripheral circuit is complicated, and the LED constant current drive chips are used, so the competitive advantage in the market is not outstanding enough. .

Summary of the invention

In order to overcome the shortcomings of the prior art, the present invention provides a linear LED load matching circuit under dual voltage. The present invention converts different topological structures according to the different situations of the first rated operating voltage and the second rated operating voltage under dual voltage. , Solve the load matching problem under dual voltage. The technical solution is as follows:

The present invention provides another linear LED load matching circuit under dual voltage, including a first load, a second load, a third load, a fourth load, a fifth load, a switch circuit, a first control unit, a second control unit and A third control unit, wherein one or more of the third load, the fourth load, and the fifth load can be short-circuited;

The first load, the fifth load, and the third control unit form a first branch through series connection, and the fourth load, the second control unit, and the second load form a second branch through series connection. The first branch and the second branch are both connected in parallel at both ends of the input voltage source, one end of the third load is connected to the second control unit through the first control unit, and the other end of the third load is connected to the switch One end of the circuit is connected, and the intermediate connection ends of the first load and the fifth load are connected to the other end of the switch circuit.

Further, the first control unit is a single-ended control component, and the first control unit includes a first constant current source and a first sampling resistor;

The third control unit is a double-ended control component, and the third control unit includes a third constant current source, a third sampling resistor, a third voltage dividing resistor, and a fourth voltage dividing resistor.

Optionally, the second control unit is a two-terminal control component, and the second control unit includes a second constant current source, a second sampling resistor, a first voltage dividing resistor, and a second voltage dividing resistor.

Optionally, the second control unit is a single-ended control component, and the second control unit includes a second constant current source and a second sampling resistor.

Further, the input voltage of the input voltage source includes a first voltage rating and a second voltage rating, wherein the second voltage rating is greater than the first voltage rating, if the second voltage rating is greater than the first voltage rating If the ratio of is greater than 2, the fourth load and the fifth load are short-circuited.

Further, if the ratio of the second voltage rating to the first voltage rating is less than 2, the third load is short-circuited.

Further, if the ratio of the second voltage rating to the first voltage rating is equal to 2, the third load, the fourth load, and the fifth load are short-circuited.

The beneficial effects brought by the technical solution provided by the present invention are as follows:

1) Solve the matching problem of linear LED load under dual voltage to adapt to two different input rated voltage standards at the same time;

2) According to the proportional relationship between the first rated operating voltage and the second rated operating voltage, different topological relationships are converted, which is suitable for load matching under different rated voltage relationships.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained from these drawings without creative work.

1 is a schematic diagram of the topology structure of a linear LED load matching circuit under dual voltage provided by an embodiment of the present invention;

FIG. 2 is a specific circuit diagram of the topology in FIG. 1 when the second voltage rating> 2* the first voltage rating;

FIG. 3 is a specific circuit diagram of the topology in FIG. 1 when the second voltage rating is less than 2* the first voltage rating;

FIG. 4 is a specific circuit diagram of the topology in FIG. 1 in the case of the second voltage rating=2*the first voltage rating;

Figure 5 (a) is the topological structure of the single-ended control circuit diagram;

Figure 5(b) is a schematic diagram of the current characteristics of the single-ended control circuit in Figure 5(a);

Figure 6 (a) is the topological structure of the double-ended control circuit diagram;

Fig. 6(b) is a schematic diagram of the current characteristics of the double-ended control circuit in Fig. 6(a).

Wherein, the reference signs include: 11-first load, 12-second load, 13-third load, 14-fourth load, 15-fifth load, 2-switch circuit, 21-switch diode, 3-th A control unit, 31-first constant current source, 32-first sampling resistor, 4-second control unit, 41-second constant current source, 42-second sampling resistor, 43-first voltage divider resistor, 44 -The second voltage divider resistor, 5- The third control unit, 51- The third constant current source, 52- The third sampling resistor, 53- The third voltage divider resistor, 54- The fourth voltage divider resistor.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is a part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and not necessarily used to describe a specific sequence or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusion.

The present invention provides a linear LED load matching circuit to match input different first voltage ratings and second voltage ratings, where the second voltage rating is greater than the first voltage rating, and the embodiment of the present invention provides dual The overall topological diagram of the linear LED load matching circuit under voltage, the topological diagrams are respectively in the second voltage rating greater than 2 times the first voltage rating, the second voltage rating is less than 2 times the first voltage rating, the second The voltage rating is equal to 2 times the first voltage rating under the three cases where there are different topology conversions.

In an embodiment of the present invention, a dual-voltage linear LED load matching circuit is provided. Referring to FIG. 1, the circuit includes a first load 11, a second load 12, a third load 13, and a fourth load 14. The fifth load 15, the switch circuit 2, the first control unit 3, the second control unit 4, and the third control unit 5. One or more of the third load 13, the fourth load 14, and the fifth load 15 can Short-circuited

The first load 11, the fifth load 15, and the third control unit 5 are connected in series to form a first branch, and the fourth load 14, the second control unit 4, and the second load 12 are connected in series to form a first branch. Two branches, the first branch and the second branch are both connected in parallel at both ends of the input voltage source, one end of the third load 13 is connected to the second control unit 4 through the first control unit 3, so The other end of the third load 13 is connected to one end of the switch circuit 2, and the intermediate connection ends of the first load 11 and the fifth load 15 are connected to the other end of the switch circuit 2.

The following is an explanation of load matching when the second voltage rating is greater than twice the first voltage rating:

If V2>2*V1, the fourth load 14 and the fifth load 15 are short-circuited, and the topological structure transformation is shown in FIG. 2. In this case, the first control unit 3 is a single-ended control component, so The first control unit 3 includes a first constant current source 31 and a first sampling resistor 32; the second control unit 4 is a double-ended control component, and the second control unit 4 includes a second constant current source 41, a second The sampling resistor 42, the first voltage dividing resistor 43, and the second voltage dividing resistor 44; the third control unit 5 is a two-terminal control component, and the third control unit 5 includes a third constant current source 51, a third sampling resistor 52, The third voltage dividing resistor 53 and the fourth voltage dividing resistor 54.

2, the circuit structure after the fourth load 14 and the fifth load 15 are short-circuited is as follows: the first load 11, the third constant current source 51, and the third sampling resistor 52 are connected in series to form a first branch. The second constant current source 41, the second sampling resistor 42, and the second load 12 are connected in series to form a second branch, and the first branch and the second branch are connected in parallel at both ends of the input voltage source , The switching diode 21, the third load 13, the first constant current source 31, and the first sampling resistor 32 form a third branch through a series connection. One end of the third branch (that is, the anode of the switching diode 21) and the first A load 11 and the middle connection end of the third constant current source 51 are connected, and the other end of the third branch (the first sampling resistor 32) is connected to the second sampling resistor 42 and the middle connection end of the second load 12; Both ends of the branch formed by the third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 in series connection are connected to the branch formed by the third constant current source 51 and the third sampling resistor 52 in series connection. The two ends are connected, the voltage dividing point between the third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 is connected to one of the control terminals of the third constant current source 51, and the third constant current source 51 is connected to the third constant current source 51. The connection point between the sampling resistors 52 is connected to the other control terminal of the third constant current source 51. Similarly, both ends of the branch formed by the first voltage dividing resistor 43 and the second voltage dividing resistor 44 in series connection are respectively formed with the second constant current source 41 and the second sampling resistor 42 in series connection. The two ends of the branch are connected, and the voltage dividing point between the first voltage dividing resistor 43 and the second voltage dividing resistor 44 is connected to one of the control terminals of the second constant current source 41, and the second constant current source 41 The connection point with the second sampling resistor 42 is connected to the other control terminal of the second constant current source 41, while the first constant current source 31 of the first control unit 3 has only one control terminal, which is connected to the first constant current source 41. The connection point between the current source 31 and the first sampling resistor 32 is connected.

The circuit characteristics of double-ended control are shown in Figure 6(a) and Figure 6(b). Before the voltage at the voltage divider point reaches a certain threshold, the current through the constant current source is constant, and the current flowing through the resistor res is detected. When I ₂ <I _ctl , I _res = I ₁ + I ₂ = I _ctl , once the threshold is reached, the current through the constant current source becomes smaller until the constant current source is turned off. When I ₂ > I _ctl , I ₁ = 0, I _res = I ₂ ; see Figure 5(a) and Figure 5(b) for the circuit characteristics of single-ended control, to detect the current flowing through the resistor res, when I ₂ <I _ctl , I _res = I ₁ +I ₂ =I _ctl , when I ₂ >I _ctl , I ₁ =0 and I _res =I ₂ .

Based on this, the working process of the circuit in FIG. 2 is as follows: when the first voltage rating V1 is input, since the voltage at the voltage division point does not reach the threshold, the second constant current source 41 and the third constant current source 51 are both constant At this time, the anode potential of the switching diode 21 is lower than the cathode potential. Therefore, the switching diode 21 is turned off, and the first constant current source has no current, the third load 13 is not connected, and only the first load 11 and the second load 11 The load 12 is connected in parallel, and the load matches V ₁ ＝V _led1 ＝V _led2 ; when the second voltage rating V2 is input, since the voltage at the voltage divider point exceeds the threshold until it is turned off, the second constant current source 41 and the third constant current source 41 The sources 51 are all turned off, the switching diode 21 is turned on, and the first constant current source 31 becomes constant current, the first load 11, the third load 13 and the second load 12 are connected in series, and the load matches V ₂ =V _led1 +V _led2 +V _led3 , that is, V2>2*V1; while the input voltage gradually increases from V1 to V2, the second constant current source 41 and the third constant current source 51 are gradually turned off, and the first constant current source 31 gradually changes It is a constant current, and the switching diode 21 is turned on and the current flowing through the switching diode 21 gradually increases. The first load 11, the second load 12, and the third load 13 are gradually switched to the series connection state.

The following is an explanation of load matching when the second voltage rating is less than twice the first voltage rating:

If V2<2*V1, the third load 13 is short-circuited, and the topological structure transformation is shown in FIG. 3. In this case, the first control unit 3 is a single-ended control component, and the first control unit 3 includes a first constant current source 31 and a first sampling resistor 32; the second control unit 4 is a single-ended control component, and the second control unit 4 includes a second constant current source 41 and a second sampling resistor 42; The third control unit 5 is a double-ended control component. The third control unit 5 includes a third constant current source 51, a third sampling resistor 52, a third voltage dividing resistor 53 and a fourth voltage dividing resistor 54.

As shown in FIG. 3, the circuit structure after short-circuiting the third load 13 is as follows: the first load 11, the fifth load 15, the third constant current source 51, and the third sampling resistor 52 are connected in series to form a first One branch, the fourth load 14, the second constant current source 41, the second sampling resistor 42, and the second load 12 are connected in series to form a second branch, and the first branch is connected in parallel with the second branch At both ends of the input voltage source, the switching diode 21, the first constant current source 31 and the first sampling resistor 32 are connected in series to form a third branch, and one end of the third branch (that is, the anode of the switching diode 21) Connected to the middle connecting end of the first load 11 and the fifth load 15, and the other end of the third branch (the first sampling resistor 32) is connected to the middle connecting end of the second constant current source 41 and the second sampling resistor 42 The third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 are connected in series to form a branch, one end of the branch is connected to the intermediate connection point of the first load 11 and the fifth load 15, and the other end is connected to the third sampling resistor 52 The low-potential end of the third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 is connected to one of the control terminals of the third constant current source 51, and the third constant current source 51 is connected to The connection point between the third sampling resistor 52 is connected to the other control terminal of the third constant current source 51. The first constant current source 31 of the first control unit 3 has only one control terminal, which is connected to the connection point between the first constant current source 31 and the first sampling resistor 32, and the second constant current source 41 is the same as the first constant current source 41. The constant current source 31 will not be repeated.

The circuit characteristics of double-ended control and single-ended control are as above, and will not be repeated here.

Based on this, the working process of the circuit in Fig. 3 is as follows: when the first voltage rating V1 is input, the voltage at the voltage division point does not reach the threshold, and the control terminal input current I _{2 of the} second constant current source 41 = 0 (because The switching diode 21 is turned off), therefore, the third constant current source 51 and the second constant current source 41 are both constant current conduction. On the other hand, the anode potential of the switching diode 21 is lower than the cathode potential at this time. Therefore, the switching diode 21 is off, and the first constant current source has no current, the first load 11 is connected in series with the fifth load 15, the fourth load 14 is connected in series with the second load 12, the two series branches are connected in parallel, and the load matches V ₁ =V _led1 + V _led5 =V _led4 +V _led2 ; when the second voltage rating V2 is input, for the second constant current source 41, I ₂ > I _ctl , so the second constant current source 41 is turned off (controlled by I ₂ ), for the third constant current source 51, the voltage at the dividing point is higher than the threshold voltage, therefore, the third constant current source 51 is turned off (controlled by V _c ), the first constant current source 31 becomes constant current, and The switching diode 21 is turned on, the first load 11 is connected in series with the second load 12, the load matches V ₂ =V _led1 +V _led2 , since V _led1 <V ₁ , V _led2 <V ₁ , that is, V2<2*V1; While the input voltage is gradually increasing from V1 to V2, the third constant current source 51 is gradually turned off, the first constant current source 31 gradually becomes a constant current, and the switching diode 21 is turned on and the current flowing through the switching diode 21 gradually increases. The second constant current source 41 is gradually turned off until the first load 11 and the second load 12 are connected in series.

The following is an explanation of load matching when the second voltage rating is equal to twice the first voltage rating:

If V2=2*V1, then the third load 13, the fourth load 14 and the fifth load 15 are all short-circuited, and the topological structure transformation is shown in Figure 4. In this case, the first control unit 3 is Single-ended control component. The first control unit 3 includes a first constant current source 31 and a first sampling resistor 32; the second control unit 4 is a single-ended control component, and the second control unit 4 includes a second constant current source. The current source 41 and the second sampling resistor 42; the third control unit 5 is a double-ended control component, and the third control unit 5 includes a third constant current source 51, a third sampling resistor 52, a third voltage divider resistor 53 and a second Four divider resistor 54.

As shown in FIG. 4, the circuit structure after the third load 13, the fourth load 14 and the fifth load 15 are all short-circuited is as follows: the first load 11, the third constant current source 51, and the third sampling resistor 52 A first branch is formed by series connection, and the second constant current source 41, the second sampling resistor 42, and the second load 12 are connected in series to form a second branch. The first branch and the second branch are connected in series. Connected in parallel to both ends of the input voltage source, the switching diode 21, the first constant current source 31 and the first sampling resistor 32 are connected in series to form a third branch. One end of the third branch (that is, the anode of the switching diode 21 ) Is connected to the middle connecting end of the first load 11 and the third constant current source 51, and the other end of the third branch (the first sampling resistor 32) is connected to the middle of the second constant current source 41 and the second sampling resistor 42 The connection ends are connected; the two ends of the branch formed by the series connection of the third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 are respectively connected to the third constant current source 51 and the third sampling resistor 52 in series At both ends of the formed branch, the voltage dividing point between the third voltage dividing resistor 53 and the fourth voltage dividing resistor 54 is connected to one of the control terminals of the third constant current source 51, and the third constant current source The connection point between 51 and the third sampling resistor 52 is connected to the other control terminal of the third constant current source 51. The first constant current source 31 of the first control unit 3 has only one control terminal, which is connected to the connection point between the first constant current source 31 and the first sampling resistor 32, and the second constant current source 41 is the same as the first constant current source 41. The constant current source 31 will not be repeated.

Based on this, the working process of the circuit in FIG. 4 is as follows: when the first rated voltage V1 is input, the voltage at the voltage dividing point does not reach the threshold, and the control terminal input current I _{2 of the} second constant current source 41 = 0 (because The switching diode 21 is turned off), therefore, the third constant current source 51 and the second constant current source 41 are both constant current conduction. On the other hand, the anode potential of the switching diode 21 is lower than the cathode potential at this time. Therefore, the switching diode 21 is turned off, and the first constant current source 31 has no current, the first load 11 is connected in parallel with the second load 12, and the load matches V ₁ =V _led1 =V _led2 ; when the second voltage rating V2 is input, for the second constant The current source 41, I ₂ > I _ctl , so the second constant current source 41 is turned off (controlled by I ₂ ). For the third constant current source 51, the voltage division point is higher than the threshold voltage, so the third constant current source The constant current source 51 is turned off (controlled by V _c ), the first constant current source 31 becomes constant current, and the switching diode 21 is turned on, the first load 11 and the second load 12 are connected in series, and the load matches V ₂ =V _led1 +V _led2 , that is, V2=2*V1; while the input voltage gradually increases from V1 to V2, the third constant current source 51 is gradually turned off, the first constant current source 31 gradually becomes constant current, and the switch The diode 21 is turned on and the current flowing through the switching diode 21 gradually increases, and the second constant current source 41 is gradually turned off until the first load 11 and the second load 12 are switched in series.

According to the different situations of the first rated working voltage and the second rated working voltage under the dual voltage, the present invention converts different topological structures to solve the load matching problem under the dual voltage.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

A linear LED load matching circuit under dual voltage, which is characterized by comprising a first load (11), a second load (12), a third load (13), a fourth load (14), and a fifth load (15) , The switch circuit (2), the first control unit (3), the second control unit (4) and the third control unit (5), wherein the third load (13), the fourth load (14), and the One or more of the five loads (15) can be short-circuited;

The first load (11), the fifth load (15), and the third control unit (5) form a first branch through a series connection, and the fourth load (14), the second control unit (4), The second load (12) is connected in series to form a second branch. The first branch and the second branch are both connected in parallel at both ends of the input voltage source. One end of the third load (13) passes through the first branch. The control unit (3) is connected to the second control unit (4), the other end of the third load (13) is connected to one end of the switch circuit (2), the first load (11), the fifth load The middle connecting end of (15) is connected to the other end of the switch circuit (2).
The load matching circuit according to claim 1, wherein the first control unit (3) is a single-ended control component, and the first control unit (3) includes a first constant current source (31) and a second A sampling resistor (32);

The third control unit (5) is a double-ended control component, and the third control unit (5) includes a third constant current source (51), a third sampling resistor (52), a third voltage dividing resistor (53) and a Four divider resistor (54).
The load matching circuit according to claim 1, wherein the second control unit (4) is a double-ended control component, and the second control unit (4) includes a second constant current source (41), a second Two sampling resistors (42), a first voltage dividing resistor (43) and a second voltage dividing resistor (44).
The load matching circuit according to claim 1, wherein the second control unit (4) is a single-ended control component, and the second control unit (4) comprises a second constant current source (41) and a Two sampling resistors (42).
The load matching circuit according to claim 1, wherein the input voltage of the input voltage source includes a first voltage rating and a second voltage rating, wherein the second voltage rating is greater than the first voltage rating, If the ratio of the second voltage rating to the first voltage rating is greater than 2, the fourth load (14) and the fifth load (15) are short-circuited.
The load matching circuit according to claim 5, wherein if the ratio of the second voltage rating to the first voltage rating is less than 2, the third load (13) is short-circuited.
The load matching circuit according to claim 5, wherein if the ratio of the second voltage rating to the first voltage rating is equal to 2, the third load (13), the fourth load (14) and The fifth load (15) is short-circuited.