Light-emitting module and lighting system using same

Abstract

The invention discloses a light-emitting module and a lighting system using the same. According to the technical scheme provided by the embodiment of the invention, the voltage signal of the output end of each LED string is regulated through the voltage regulation circuit which is coupled in the current path of each LED string in series, and the current ratio of each LED string is set through the current distribution circuit, so that the current flowing through each LED string is accurately controlled, the current precision can be improved, and the control cost is reduced.

Description

Technical Field

[0001] This invention relates to power electronics technology, specifically to power electronics technology, and more specifically to light-emitting modules and lighting systems using the same. Background Technology

[0002] In existing technologies, semiconductor light sources such as light-emitting diodes (LEDs) have gradually replaced traditional fluorescent lamps, offering advantages such as high energy conversion and low operating costs. LED technology provides an efficient light source capable of producing a variety of lighting effects in many applications. Due to these advantages, lighting devices include an LED string consisting of one or more LEDs connected in series, and a processor that provides a substantially constant drive current. This processor can independently control these LEDs, providing a constant output current within a certain range to drive the LED string to emit different colors and color-changing lighting effects at different output currents. The term "constant drive current" as used herein refers to outputting a substantially constant current to the LED string at a selected drive current.

[0003] Light sources possess various luminous characteristics, such as correlated color temperature (CCT) and luminous flux. Correlated color temperature is a physical quantity describing the color characteristics of a light source; it refers to the temperature value corresponding to the chromaticity point closest to the blackbody radiation trajectory on a uniform chromaticity diagram, expressed in absolute temperature (K). Luminous flux refers to the energy radiated by a light source per unit time into the surrounding space that causes visual perception, measured in lumens. The luminous flux of most LEDs varies with the current driving them. However, to save costs, the luminous characteristics of most lighting devices are predetermined and cannot be adaptively selected to suit different application scenarios. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a light-emitting module and a lighting system, which expands the application scenarios of the light-emitting module by precisely distributing the current flowing through each LED string.

[0005] According to a first aspect of the present invention, a light-emitting module is provided. The light-emitting module includes:

[0006] The driver end receives the drive current;

[0007] The first LED string coupled to the driver terminal;

[0008] A second LED string coupled to the driver terminal;

[0009] The voltage regulation circuit includes a first input terminal and a second input terminal, respectively coupled to the negative terminals of the first LED string and the second LED string; and first and second output terminals for generating a first voltage signal and a second voltage signal.

[0010] The current distribution circuit includes a first branch and a second branch for receiving the first voltage signal and the second voltage signal, respectively; and is configured to select the current passing through the first LED string and the second LED string according to the current distribution ratio signal.

[0011] Preferably, the voltage regulation circuit is configured to control the first voltage signal and the second voltage signal to be equal.

[0012] Preferably, the voltage regulation circuit adjusts the first voltage signal and the second voltage signal to keep them equal based on the difference between the first voltage signal and the second voltage signal.

[0013] Preferably, the voltage regulation circuit is configured to control the ratio of the first voltage signal and the second voltage signal to be the ratio of a second proportional coefficient and a first proportional coefficient.

[0014] Preferably, the voltage regulation circuit is configured to control the ratio of the first voltage signal and the second voltage signal to be the ratio of a second proportional coefficient and a first proportional coefficient based on the first conversion voltage and the second conversion voltage, wherein the first conversion voltage is the product of the first voltage signal and the first proportional coefficient, the second conversion voltage is the product of the second voltage signal and the second proportional coefficient, and the ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string and the second LED string.

[0015] Preferably, the voltage regulation circuit includes:

[0016] A first controlled current source is coupled between the negative terminal of the first LED string and the first output terminal; and

[0017] A second controlled current source is coupled between the negative terminal of the second LED string and the second output terminal;

[0018] The first controlled current source and the second controlled current source are controlled by the first voltage signal and the second voltage signal.

[0019] Preferably, the first controlled current source includes a first transistor coupled between the negative terminal of the first LED string and the first output terminal; the second controlled current source includes a second transistor coupled between the negative terminal of the second LED string and the second output terminal.

[0020] The control terminals of the first transistor and the second transistor are controlled by the first voltage signal and the second voltage signal.

[0021] Preferably, the voltage regulation circuit includes:

[0022] The control circuit is configured to generate a first control signal and a second control signal based on the first voltage signal and the second voltage signal, respectively, to be provided to the control terminals of the first controlled current source and the second controlled current source.

[0023] Preferably, the absolute values ​​of the first control signal and the second control signal are proportional to the voltage difference between the first voltage signal and the second voltage signal, and the first control signal and the second control signal change in opposite directions.

[0024] Preferably, the control circuit includes:

[0025] The first amplifier includes a first input terminal for receiving the second voltage signal, a second input terminal for receiving the first voltage signal, and an output terminal for generating the first control signal; and

[0026] The second amplifier includes a first input terminal for receiving a first voltage signal, a second input terminal for receiving a second voltage signal, and an output terminal for generating the second control signal.

[0027] Preferably, the control circuit includes:

[0028] The first amplifier includes a first input terminal for receiving the second converted voltage, a second input terminal for receiving the first converted voltage, and an output terminal for generating the first control signal; and

[0029] The second amplifier includes a first input terminal for receiving the first converted voltage, a second input terminal for receiving the second converted voltage, and an output terminal for generating the second control signal.

[0030] The first conversion voltage is the product of the first voltage signal and the first proportional coefficient, and the second conversion voltage is the product of the second voltage signal and the second proportional coefficient.

[0031] Preferably, the first branch includes a first resistor module coupled between the first voltage signal and the reference ground; the second branch includes a second resistor module coupled between the second voltage signal and the reference ground.

[0032] Preferably, the first voltage signal and the second voltage signal are controlled to be equal, and the ratio of the resistance values ​​of the first resistor module and the second resistor module is the ratio of the current flowing through the first LED string and the second LED string.

[0033] Preferably, the first resistor module includes at least one resistor coupled in parallel, and the second resistor module includes at least one resistor coupled in parallel.

[0034] Preferably, the first resistor module includes at least one transistor coupled in parallel, and the second resistor module includes at least one transistor coupled in parallel.

[0035] Preferably, the ratio of the first voltage signal and the second voltage signal is controlled to be the ratio of the second proportional coefficient and the first proportional coefficient, the resistance values ​​of the first resistor module and the second resistor module are equal, and the ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string and the second LED string.

[0036] Preferably, the light-emitting module further includes:

[0037] At least one third LED string,

[0038] The voltage regulation circuit includes a third input terminal corresponding to the at least one third LED string, which is coupled to the negative terminal of the corresponding third LED string, and a third output terminal corresponding to the at least one third LED string, which is used to generate a corresponding third voltage signal.

[0039] The current distribution circuit includes a branch corresponding to the at least one third LED string for receiving a corresponding third voltage signal and is configured to select the current passing through the at least one third LED string according to the current distribution ratio signal.

[0040] According to a second aspect of the present invention, a lighting system is provided. The lighting system includes:

[0041] A constant current source is configured to generate a drive current; and

[0042] Any of the light-emitting modules described in the first aspect, wherein the light-emitting module receives the driving current to emit light.

[0043] Preferably, the first LED string generates light with a first correlated color temperature (CCT), and the second LED string generates light with a second correlated color temperature (CCT).

[0044] The technical solution of this invention adjusts the voltage signal at the output terminal of a voltage regulation circuit connected in series in the current path of each LED string, and sets the current ratio through each LED string through a current distribution circuit to accurately control the current flowing through each LED string, thereby improving current accuracy and reducing control costs. Attached Figure Description

[0046] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0047] Figure 1 This is a circuit block diagram of the lighting system according to the first embodiment of the present invention;

[0048] Figure 2A This is a circuit block diagram of the light-emitting module according to the first embodiment of the present invention;

[0049] Figure 2B This is a circuit block diagram of the light-emitting module according to the second embodiment of the present invention;

[0050] Figure 3 This is a circuit block diagram of the light-emitting module according to the third embodiment of the present invention;

[0051] Figure 4 This is a circuit block diagram of the control circuit according to an embodiment of the present invention;

[0052] Figure 5 This is a waveform diagram of the working state of the light-emitting module according to an embodiment of the present invention;

[0053] Figure 6 This is a circuit block diagram of the light-emitting module according to the fourth embodiment of the present invention;

[0054] Figure 7 This is a circuit block diagram of a lighting system according to a second embodiment of the present invention. Detailed Implementation

[0055] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0056] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0057] Furthermore, it should be understood that in the following description, "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by electrical or electromagnetic connections. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to another element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0058] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0059] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0060] Figure 1 This is a circuit block diagram of the lighting system according to the first embodiment of the present invention. Figure 1 As shown, the lighting system in this embodiment includes a constant current source 1 and a light-emitting module 2. The constant current source 1 receives an input voltage and generates an adjustable drive current Id. The drive current generated by the constant current source 1 is variable; for example, the drive current can vary continuously or stepwise within a predetermined range. In this embodiment, the constant current source 1 can control the drive current, arbitrarily selected within this variation range, to remain at a constant value. In one embodiment, the constant current source 1 receives an input voltage generated by a dimmer 102, which is configured to be generated by cutting off the leading edge of a voltage signal waveform from an AC voltage 101 via the dimmer 102. The constant current source 1 can provide a drive current varying from zero to a maximum value based on the voltage variation amplitude of the dimmer to achieve a dimming function. When the dimming voltage is selected, the drive current generated by the constant current source remains at a constant value. The drive terminal of the light-emitting module 2 receives the drive current Id to provide energy to the light source. In this embodiment, the light source is a light-emitting diode (LED).

[0061] In this embodiment, the light-emitting module 2 includes a first LED string (LED1) and a second LED string (LED2). The first LED string (LED1) and the second LED string (LED2) are connected to the driving terminal of the light-emitting module to receive a driving current (Id). The first LED string and the second LED string may include different numbers and types of LEDs. The first LED string (LED1) generates light with a first correlated color temperature (CCT). For example, the first LED string (LED1) may include warm yellow LEDs. The second LED string (LED2) generates light with a second correlated color temperature (CCT). For example, the second LED string (LED2) may include red or red-orange LEDs.

[0062] The light-emitting module 2 includes a voltage regulation circuit 10 and a current distribution circuit 11. The voltage regulation circuit 10 includes a first input terminal A0 and a second input terminal A1, as well as a first output terminal B0 and a second output terminal B1. The first input terminal A0 is connected to the negative terminal of the first LED string LED1, and the second input terminal A1 is connected to the negative terminal of the second LED string LED2. The first output terminal B0 and the second output terminal B1 generate a first voltage signal and a second voltage signal, respectively. The current distribution circuit 11 includes a first branch and a second branch for receiving the first voltage signal and the second voltage signal, respectively. The first branch is connected between the first output terminal B0 and a reference ground, and the second branch is connected between the second output terminal B1 and the reference ground. The current distribution circuit 11 is configured to select the ratio of the current flowing through the first LED string LED1 and the second LED string LED2 according to the current ratio distribution signal. Thus, the first LED string (LED1), voltage regulation circuit 10, and first branch form a first current path; the second LED string (LED2), voltage regulation circuit 10, and second branch form a second current path. In this embodiment, the voltage regulation module controls the first and second voltage signals to be in a controlled state. Based on this, the current distribution circuit can accurately divide the drive current Id according to the current distribution ratio signal to set the current flowing through the first LED string (LED1) and the second LED string (LED2). The sum of the currents flowing through the first LED string (LED1) and the second LED string (LED2) is the drive current Id, and the ratio of the currents flowing through the first LED string (LED1) and the second LED string (LED2) is the current ratio set by the current distribution circuit, for example, based on the user's requirements.

[0063] In one embodiment, the voltage regulation circuit 10 controls the first voltage signal and the second voltage signal to remain equal, thereby the current flowing through the first LED string LED1 and the second LED string is determined by the resistance values ​​of the first branch and the second branch. Since the voltage signals at both ends of the first branch and the second branch are equal, the current flowing through the first LED string LED1 is related to the resistance of the circuit components in the first branch, and the current flowing through the second LED string is related to the resistance of the circuit components in the second branch. Different resistance levels result in different currents, thus achieving current shunt control.

[0064] In one embodiment, the voltage regulation circuit 10 adjusts the first voltage signal and the second voltage signal to maintain their equality based on the difference between the first voltage signal and the second voltage signal, thereby forming negative feedback regulation, which can automatically correct deviations and resist external interference. In this embodiment, the light-emitting module can achieve precise current distribution through negative feedback regulation to achieve different light-emitting characteristics.

[0065] In one embodiment, the voltage regulation circuit 10 controls the ratio of the first voltage signal and the second voltage signal to be the ratio of the second proportional coefficient to the first proportional coefficient. The resistance values ​​of the first branch and the second branch in the current distribution circuit are kept equal, so that the current flowing through the first LED string LED1 and the second LED string is determined by the ratio of the first voltage signal and the second voltage signal.

[0066] In one embodiment, the voltage regulation circuit 10 includes a first LED string and a first controlled current source connected in series, as well as a second LED string and a second controlled current source. A current distribution circuit sets the ratio of a first current flowing through the first LED string (LED1) and a second current flowing through the second LED string (LED2), the sum of which is the drive current Id. The light-emitting module includes a control circuit for generating control signals for the first and second controlled current sources. The control circuit controls the first and second controlled current sources based on the voltage difference between the first and second voltage signals, such that the first and second voltage signals are equal, thereby forming negative feedback control.

[0067] When the number of LED strings is adjusted, the sum of the voltage on the LED string and the voltage across the controlled current source changes, causing a deviation in the voltage values ​​of the first voltage signal and the second voltage signal. At this time, the voltage regulation circuit can control the first voltage signal and the second voltage signal to be in a controlled state, thereby maintaining an accurate current distribution ratio and remaining in a stable state.

[0068] In one packaged application, the light-emitting module can be an integrated circuit, with a current matching circuit serving as an external circuit of the integrated circuit to allow the user to set the current value flowing through each LED string.

[0069] Figure 2A This is a circuit block diagram of the light-emitting module according to the first embodiment of the present invention. Figure 2A As shown, the light-emitting module includes a first LED string LED1 and a second LED string LED2, a voltage regulation circuit 10, and a current distribution circuit 11. The voltage regulation circuit 10 includes a first controlled current source 2A and a second controlled current source 2B. The first LED string LED1 and the first controlled current source 2A are connected in series between the driving terminal and the first output terminal B0 of the voltage regulation circuit 10 to receive the driving current Id. The second LED string LED2 and the second controlled current source 2B are connected in series between the driving terminal and the second output terminal B1 of the voltage regulation circuit 10 to receive the driving current Id. The sum of the currents flowing through the first LED string LED1 and the second LED string LED2 is the driving current Id.

[0070] In this embodiment, the voltage regulation circuit 10 further includes a control circuit 2C. The control circuit 2C samples a first voltage signal at the first output terminal B0 and a second voltage signal at the second output terminal B1, and generates control signals for the first controlled current source and the second controlled current source.

[0071] In this embodiment, the current distribution circuit 11 includes a first branch and a second branch. The first branch is connected between the first output terminal B0 of the voltage regulation circuit 10 and the reference ground, and the second branch is connected between the second output terminal B1 of the voltage regulation circuit 10 and the reference ground. The first branch includes a first resistor module, and the second branch includes a second resistor module.

[0072] In one embodiment, the first voltage signal and the second voltage signal are controlled to be equal, and the ratio of the resistance values ​​of the first resistor module and the second resistor module is the ratio of the current flowing through the first LED string LED1 and the second LED string LED2.

[0073] In this embodiment, the first resistor module includes resistors R connected in parallel. A And R1, the second resistor module includes resistor R B Resistance R A Resistor R is connected between the first output terminal B0 and the reference ground. B It is connected between the second output terminal B1 and the reference ground. In the event of resistor R1 failure, the ratio of the currents I1 and I2 flowing through the first LED string LED1 and the second LED string LED2 is equal to the resistance R. A and R B The ratio. The current distribution circuit 11 sets the resistor R according to the current distribution ratio signal. A and resistance R B The resistance value can be adjusted to change the current flowing through each LED string.

[0074] In this embodiment, the current distribution circuit is illustrated by changing the resistance value of the first resistor module. Figure 2A As shown, the first resistor module also includes a switch S and a resistor R1 connected in series. The current distribution circuit controls the switching of switch S to turn on and off according to the current distribution ratio signal, thereby changing the resistance value of the first resistor module. When switch S is on, the resistance R1 in the first resistor module... A When connected in parallel with resistor R1, the resistance of the first resistor module decreases, the current flowing through the first LED string (LED1) increases, and the current flowing through the second LED string (LED2) decreases. When switch S is off, the ratio of the currents I1 and I2 flowing through the second LED string (LED2) is equal to the resistance R. A and R B The ratio. It should be understood that any circuit implementation that can change the resistance value of the first resistor module and / or the second resistor module can be used in the current distribution circuit of this embodiment of the invention, and there is no limitation thereto.

[0075] Figure 2B This is a circuit block diagram of the light-emitting module according to the second embodiment of the present invention. Figure 2B As shown, the light-emitting module includes a first LED string LED1 and a second LED string LED2, a voltage regulation circuit 10, and a current distribution circuit 11. The voltage regulation circuit 10 includes a first controlled current source 2A and a second controlled current source 2B. The first LED string LED1 and the first controlled current source are connected in series between the driving terminal and the first output terminal B0 of the voltage regulation circuit 10 to receive the driving current Id. The second LED string LED2 and the second controlled current source are connected in series between the driving terminal and the second output terminal B1 of the voltage regulation circuit 10 to receive the driving current Id. The sum of the currents flowing through the first LED string LED1 and the second LED string LED2 is the driving current Id.

[0076] In this embodiment, the voltage regulation circuit 10 further includes a control circuit 2C. The control circuit 2C is used to control the ratio of the first voltage signal and the second voltage signal to be the ratio of the second proportional coefficient K2 and the first proportional coefficient K1, so as to control the ratio of the current flowing through the first LED string LED1 and the second LED string LED2 to be the ratio of the second proportional coefficient and the first proportional coefficient.

[0077] In this embodiment, the first branch includes a first resistor module, and the second branch includes a second resistor module. The resistance values ​​of the first resistor module and the second resistor module are equal. The first resistor module includes a resistor R. A The second resistor module includes resistor R B Where the resistance R A and R B The resistance values ​​are equal. The current distribution module 11 also includes a first proportional circuit 200 and a second proportional circuit 201. The first proportional circuit 200 is used to multiply the first voltage signal by the first proportional coefficient K1 to generate a first conversion voltage V11, and the first proportional circuit 201 is used to multiply the second voltage signal by the second proportional coefficient K2 to generate a second conversion voltage V12, wherein the first conversion voltage V11 and the second conversion voltage are equal. The control circuit 2C receives the first conversion voltage V11 and the second conversion voltage V12, and generates a first control signal and a second control signal. The first control signal is provided to the control terminal of the first controlled current source 2A, and the second control signal is provided to the control terminal of the second controlled current source 2B, thereby controlling the ratio of the first voltage signal and the second voltage signal to be the ratio of the second proportional coefficient K2 and the first proportional coefficient K1. At this time, the ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string LED1 and the second LED string LED2, that is, the ratio of the current flowing through the first LED string LED1 and the second LED string LED2 is the ratio of the second proportional coefficient and the first proportional coefficient.

[0078] Figure 3 This is a circuit block diagram of the light-emitting module according to the third embodiment of the present invention. Figure 3 As shown, the light-emitting module includes a first LED string LED1 and a second LED string LED2, a voltage regulation circuit 10, and a current distribution circuit 11. The voltage regulation circuit 10 includes transistors M1 and M2. The first LED string LED1 and transistor M1 are connected in series between the driving terminal and the first output terminal B0 of the voltage regulation circuit 10 to receive the driving current Id. The second LED string LED2 and transistor M2 are connected in series between the driving terminal and the second output terminal B1 of the voltage regulation circuit 10 to receive the driving current Id. The sum of the currents flowing through the first LED string LED1 and the second LED string LED2 is the driving current Id.

[0079] In this embodiment, the voltage regulation circuit 10 further includes a control circuit 2C. The control circuit 2C generates a first control signal and a second control signal based on the first voltage signal at the first output terminal B0 and the second voltage signal at the second output terminal B1. The first control signal and the second control signal are provided to the control terminals, such as the gates, of transistors M1 and M2.

[0080] In one embodiment, the control circuit 2C controls transistors M1 and M2 based on the voltage difference between a first voltage signal and a second voltage signal, so that the first voltage signal and the second voltage signal are equal, thereby forming negative feedback control. In one implementation, the control circuit 2C samples the first voltage signal at the first output terminal B0 and the second voltage signal at the second output terminal B1, and generates first and second control signals based on the voltage difference between the first and second voltage signals. The first control signal is provided to the control terminal of transistor M1, and the second control signal is also provided to the control terminal of transistor M1. When the current distribution circuit selects a current distribution ratio, the voltage difference between the first and second output terminals B0 and B1 changes. The control circuit 2C controls the first and second control signals to adjust the voltages at the two power terminals of the corresponding transistors, so that the first and second voltage signals are equal. When the first voltage signal increases, the first control signal decreases, that is, the voltage at the gate of transistor M1 decreases, which in turn decreases the drain voltage of transistor M1, i.e., the first voltage signal decreases, and vice versa.

[0081] In another embodiment, control circuit 2C controls transistors M1 and M2 based on a first voltage signal and a second voltage signal, such that the ratio of the first voltage signal and the second voltage signal is equal to the ratio of a second proportional coefficient to a first proportional coefficient, thereby forming negative feedback control. In one implementation, a current distribution circuit samples the first voltage signal at a first output terminal B0 and the second voltage signal at a second output terminal B1 and generates a first conversion voltage and a second conversion voltage, wherein the first conversion voltage is the product of the first voltage signal and a first proportional coefficient, and the second conversion voltage is the product of the second voltage signal and a second proportional coefficient. Control circuit 2C receives the first conversion voltage and the second conversion voltage and generates first and second control signals, the first control signal being provided to the control terminal of transistor M1, and the second control signal being provided to the control terminal of transistor M1. The first conversion voltage and the second conversion voltage are controlled to be equal, thereby the first control signal and the second control signal can control the ratio of the first voltage signal and the second voltage signal to be equal to the ratio of the second proportional coefficient to the first proportional coefficient, and simultaneously the ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string and the second LED string.

[0082] The voltage regulation circuit in this application is described using an N-type transistor as an example. It can be a gallium nitride transistor, a bipolar junction transistor (BJT), an insulated-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a field-controlled thyristor (MCT), a gate-turn-off thyristor (GTO), or a transmission gate (TG), etc. The present invention does not limit it to these types.

[0083] Figure 4 This is a circuit block diagram of the control circuit according to an embodiment of the present invention. The control circuit includes a first amplifier A1 and a second amplifier A2, used to generate a first control signal G, respectively. M1 Second control signal G M2 .

[0084] In one embodiment, the first amplifier A1 generates a first control signal G based on the voltage difference between the first output terminal B0 and the second output terminal B1. M1 This is provided to the control terminal of transistor M1. The second amplifier A2 generates a second control signal G based on the voltage difference between the second output terminal B1 and the first output terminal B0.M2 This is provided to the control terminal of transistor M2. The voltages at the first output terminal B0 and the second output terminal B1 are respectively the first voltage signal V. A Second voltage signal V B The first amplifier A1 includes a first input terminal, such as a non-inverting input terminal, for receiving a second voltage signal V. B and a second input terminal, such as an inverting input terminal, for receiving the first voltage signal V. A The second amplifier A2 includes a first input terminal, such as a non-inverting input terminal, for receiving a first voltage signal V. A and a second input terminal, such as an inverting input terminal, for receiving a second voltage signal V. B First control signal G M1 Second control signal G M2 The changes are in the opposite direction, for example, the first voltage signal V A Greater than the second voltage signal V B First control signal G M1 Decrease, second control signal G M2 As the current increases, the current flowing through transistor M1 decreases, and the current flowing through transistor M2 increases, thereby affecting the first voltage signal V. A Decrease, second voltage signal V B Increase, and eventually maintain the first voltage signal V A Second voltage signal V B equal.

[0085] In another embodiment, the first amplifier A1 generates a first control signal G based on the voltages at the first output terminal B0 and the second output terminal B1. M1 This is provided to the control terminal of transistor M1. The second amplifier A2 generates a second control signal G based on the voltages at the second output terminal B1 and the first output terminal B0. M2 This is provided to the control terminal of transistor M2. The voltages at the first output terminal B0 and the second output terminal B1 are respectively the first voltage signal V. A Second voltage signal V B The first amplifier A1 includes a first input terminal, such as a non-inverting input terminal, for receiving a second converted voltage, and a second input terminal, such as an inverting input terminal, for receiving the first converted voltage. The second amplifier A2 includes a first input terminal, such as a non-inverting input terminal, for receiving the first converted voltage, and a second input terminal, such as an inverting input terminal, for receiving the second converted voltage. The first voltage signal is multiplied by a first proportional coefficient to generate the first converted voltage, and the second voltage signal is multiplied by a second proportional coefficient to generate the second converted voltage. The first converted voltage and the second converted voltage are equal.

[0086] Figure 5This is a waveform diagram of the working light-emitting module in an embodiment of the present invention. Figure 5 The current distribution ratio signal V is shown in sequence. S The first voltage signal V A The second voltage signal V B First control signal G M1 Second control signal G M2 And the currents I1 and I2 flowing through the first LED string LED1 and the second LED string LED2, respectively. In this embodiment, the voltage regulation circuit controls the first voltage signal V. A Second voltage signal V B Let's take equality as an example. At time t0, the current distribution ratio signal V... S When switched to an active signal, the current distribution circuit controls the resistance of the first resistor module in the first branch to decrease, and the first voltage signal V... A Decrease, second voltage signal V B The basic structure remains unchanged, with the first control signal G remaining the same. M1 Increase, second control signal G M2 As the current decreases, the current I1 flowing through transistor M1 increases, and the current I2 flowing through transistor M2 decreases, thereby affecting the first voltage signal V. A Increase, second voltage signal V B Decrease, and eventually maintain the first voltage signal V A Second voltage signal V B Equal. At time t1, the current distribution ratio signal V S When the signal is switched to invalid, the resistance of the first resistor module in the first branch of the current distribution circuit increases, and the first voltage signal V... A Increase, second voltage signal V B The basic structure remains unchanged, with the first control signal G remaining the same. M1 Decrease, second control signal G M2 As the voltage increases, the current I1 flowing through transistor M1 decreases, and the current I2 flowing through transistor M2 increases, thereby affecting the first voltage signal V. A Decrease, second voltage signal V B Increase, and eventually maintain the first voltage signal V A Second voltage signal V B equal.

[0087] Figure 6This is a circuit block diagram of the light-emitting module according to the fourth embodiment of the present invention. The difference from the embodiment in FIG2 is that, in this embodiment, transistors replace resistors in the first and second branches of the current distribution circuit. The first resistor module includes transistors Q1 and Q2 connected in parallel, and the second resistor module includes transistors Q3 and Q4 connected in parallel. Transistors Q1 and Q2 are connected between the first output terminal B0 and the reference ground, and transistors Q3 and Q4 are connected between the second output terminal B1 and the reference ground. Transistors Q1-Q4 can be considered as a resistor controlled by a driving voltage. This driving voltage is the difference between the voltage between the gate and source and the turn-on threshold voltage. In this embodiment, the gates of transistors Q1-Q4 are respectively connected to the driving voltage via switches S1-S4, which is generated by the control circuit 2C. The current distribution circuit 11 controls switches S1-S4 according to the current distribution ratio signal. When switches S1-S4 are turned on, the gates of transistors Q1-Q4 are connected to the driving voltage. When switches S1-S4 are turned off, the gates of transistors Q1-Q4 are left floating, thereby changing the resistance values ​​of the first and second resistor modules. It should be understood that any device with a certain resistance can be used in the current distribution circuit of this application embodiment, and the present invention is not limited thereto.

[0088] Figure 7 This is a circuit block diagram of a lighting system according to a second embodiment of the present invention. Figure 7 As shown, the lighting system in this embodiment includes a constant current source 1 and a light-emitting module 2. In this embodiment, the light-emitting module 2 includes N LED strings LED1-LEDN, and all N LED strings LED1-LEDN are connected to the driving terminal of the light-emitting module to receive the driving current Id. In this embodiment, the N LED strings LED1-LEDN may include different numbers and different types of LEDs.

[0089] The light-emitting module 2 includes a voltage regulation circuit 70 and a current distribution circuit 71. The voltage regulation circuit 70 includes N input terminals A0-A(N-1) and N output terminals B0-B(N-1). The N input terminals are respectively connected to the negative terminals of the N LED strings LED1-LEDN, and the N output terminals generate N voltage signals, namely the first voltage signal to the Nth voltage signal. The current distribution circuit 71 includes a first branch to the Nth branch, used to receive the first voltage signal to the Nth voltage signal respectively. For example, the first branch is connected between the first output terminal and the reference ground, and the second branch is connected between the second output terminal and the reference ground. The current distribution circuit 71 is configured to select the ratio of the current flowing through the first LED string LED1 to the Nth LED string LEDN according to the current ratio distribution signal.

[0090] In one embodiment, the voltage regulation circuit 70 is configured to control N voltage signals to remain equal. When one of the voltage signals increases, the voltage at the control terminal of the corresponding transistor decreases to control the voltage signal to decrease. When one of the voltage signals decreases, the voltage at the control terminal of the corresponding transistor increases to control the voltage signal to increase. In this embodiment, the voltage regulation circuit can adopt any of the implementation methods described in the above embodiments, and the present invention does not limit it in this way.

[0091] In this embodiment, the voltage regulation module controls N voltage signals to be in a controlled state. Based on this, the current distribution circuit can accurately divide the drive current Id according to the current distribution ratio signal to set the current flowing through the N LED strings. The sum of the currents flowing through the N LED strings is the drive current Id, and the ratio of the currents flowing through the N LED strings is the current ratio set by the current distribution circuit, for example, the current ratio is set based on the user's needs.

[0092] The technical solution of this invention adjusts the voltage signal at the output terminal of the voltage regulation circuit connected in series in the current path of each LED string, and sets the current ratio through each LED string through the current distribution circuit, so as to accurately control the current flowing through each LED string, thereby improving the current accuracy and reducing the control cost.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A light-emitting module, comprising: The driver end receives the drive current; The first LED string coupled to the driver terminal; A second LED string coupled to the driver terminal; The voltage regulation circuit includes a first input terminal and a second input terminal, which are respectively coupled to the negative terminals of the first LED string and the second LED string; And first and second output terminals, used to generate a first voltage signal and a second voltage signal; as well as The current distribution circuit includes a first branch and a second branch, which are used to receive the first voltage signal and the second voltage signal, respectively. It is configured to select the current passing through the first LED string and the second LED string according to the current distribution ratio signal.

2. The light-emitting module according to claim 1, characterized in that, The voltage regulation circuit is configured to control the first voltage signal and the second voltage signal to be equal.

3. The light-emitting module according to claim 2, characterized in that, in, The voltage regulation circuit adjusts the first voltage signal and the second voltage signal to keep them equal based on the difference between the first voltage signal and the second voltage signal.

4. The light-emitting module according to claim 1, characterized in that, The voltage regulation circuit is configured to control the ratio of the first voltage signal and the second voltage signal to be the ratio of a second proportional coefficient to a first proportional coefficient.

5. The light-emitting module according to claim 4, characterized in that, The voltage regulation circuit is configured to control the ratio of the first voltage signal and the second voltage signal to be the ratio of a second proportional coefficient and a first proportional coefficient based on a first conversion voltage and a second conversion voltage, wherein the first conversion voltage is the product of the first voltage signal and the first proportional coefficient, the second conversion voltage is the product of the second voltage signal and the second proportional coefficient, and the ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string and the second LED string.

6. The light-emitting module according to claim 1, characterized in that, The voltage regulation circuit includes: A first controlled current source is coupled between the negative terminal of the first LED string and the first output terminal; and A second controlled current source is coupled between the negative terminal of the second LED string and the second output terminal; The first controlled current source and the second controlled current source are controlled by the first voltage signal and the second voltage signal.

7. The light-emitting module according to claim 6, characterized in that, The first controlled current source includes a first transistor coupled between the negative terminal of the first LED string and the first output terminal; the second controlled current source includes a second transistor coupled between the negative terminal of the second LED string and the second output terminal. The control terminals of the first transistor and the second transistor are controlled by the first voltage signal and the second voltage signal.

8. The light-emitting module according to claim 6, characterized in that, The voltage regulation circuit includes: The control circuit is configured to generate a first control signal and a second control signal based on the first voltage signal and the second voltage signal, respectively, to be provided to the control terminals of the first controlled current source and the second controlled current source.

9. The light-emitting module according to claim 8, characterized in that, The absolute values ​​of the first control signal and the second control signal are proportional to the voltage difference between the first voltage signal and the second voltage signal, and the first control signal and the second control signal change in opposite directions.

10. The light-emitting module according to claim 8, characterized in that, The control circuit includes: The first amplifier includes a first input terminal for receiving the second voltage signal, a second input terminal for receiving the first voltage signal, and an output terminal for generating the first control signal. as well as The second amplifier includes a first input terminal for receiving a first voltage signal, a second input terminal for receiving a second voltage signal, and an output terminal for generating the second control signal.

11. The light-emitting module according to claim 8, characterized in that, The control circuit includes: The first amplifier includes a first input terminal for receiving the second conversion voltage, a second input terminal for receiving the first conversion voltage, and an output terminal for generating the first control signal. as well as The second amplifier includes a first input terminal for receiving the first converted voltage, a second input terminal for receiving the second converted voltage, and an output terminal for generating the second control signal. The first conversion voltage is the product of the first voltage signal and the first proportional coefficient, and the second conversion voltage is the product of the second voltage signal and the second proportional coefficient.

12. The light-emitting module according to claim 1, characterized in that, The first branch includes a first resistor module coupled between the first voltage signal and the reference ground; the second branch includes a second resistor module coupled between the second voltage signal and the reference ground.

13. The light-emitting module according to claim 12, characterized in that, The first voltage signal and the second voltage signal are controlled to be equal, and the ratio of the resistance values ​​of the first resistor module and the second resistor module is the ratio of the current flowing through the first LED string and the second LED string.

14. The light-emitting module according to claim 12, characterized in that, The first resistor module includes at least one resistor coupled in parallel, and the second resistor module includes at least one resistor coupled in parallel.

15. The light-emitting module according to claim 12, characterized in that, The first resistor module includes at least one transistor coupled in parallel, and the second resistor module includes at least one transistor coupled in parallel.

16. The light-emitting module according to claim 12, characterized in that, The ratio of the first voltage signal and the second voltage signal is controlled to be the ratio of the second proportional coefficient and the first proportional coefficient. The resistance values ​​of the first resistor module and the second resistor module are equal. The ratio of the first voltage signal and the second voltage signal is the ratio of the current flowing through the first LED string and the second LED string.

17. The light-emitting module according to claim 1, characterized in that, The light-emitting module also includes: At least one third LED string; The voltage regulation circuit includes a third input terminal corresponding to the at least one third LED string, which is coupled to the negative terminal of the corresponding third LED string, and a third output terminal corresponding to the at least one third LED string, for generating a voltage signal. The current distribution circuit includes a branch corresponding to the at least one third LED string for receiving a corresponding voltage signal and is configured to select the current passing through the at least one third LED string according to the current distribution ratio signal.

18. A lighting system comprising: A constant current source is configured to generate a drive current; and The light-emitting module according to any one of claims 1-17, wherein the light-emitting module receives the driving current to emit light.

19. The lighting system according to claim 18, characterized in that, The first LED string produces light with a first correlated color temperature (CCT), and the second LED string produces light with a second correlated color temperature (CCT).

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