CN115442938A - LED dimming device and LED lighting system - Google Patents

Abstract

The embodiment of the present disclosure discloses an LED dimming device and an LED system. Wherein, the LED dimming device includes: a voltage detection module and a current controller; the voltage detection module is used to be connected between the positive pole and the negative pole of the driving power supply of the LED lamp or light string, so as to sample the output voltage of the driving power supply; The voltage input end of the current controller is connected to the voltage output end of the voltage detection module, and the current controller is used to connect with the LED lamp or light string in series to control the LED lamp according to the output voltage of the driving power supply. Current for LED lights or light strings. By adopting the embodiments of the present disclosure, the light intensity of the LED lamp can be adjusted by adjusting the output voltage of the LED driving power supply.

Description

LED dimming device and LED lighting system

technical field

Embodiments of the present disclosure relate to the technical field of current control, and in particular to an LED dimming device and an LED lighting system.

Background technique

How to effectively control the light intensity of LED lighting circuits or systems is always a relatively big challenge, especially in the application scenario where a single LED driving power supply (driver power supply) drives multiple LED light strings. The brightness of an LED light is linear with the current passing through it. Therefore, an embodiment of the present disclosure proposes a device for adjusting the brightness of the LED lamp by controlling the current of the LED lamp, so as to make the LED lighting or the lighting system more efficient and reliable.

Contents of the invention

Embodiments of the present invention provide an LED dimming device and an LED lighting system to solve or alleviate one or more technical problems in the prior art.

In one aspect, an embodiment of the present invention provides an LED dimming device, which includes a voltage detection module and a current controller; the voltage detection module is used to be connected between the positive pole and the negative pole of the driving power supply of the LED lamp or light string, to sample the output voltage of the driving power supply; the voltage input end of the current controller is connected to the voltage output end of the voltage detection module, and the current controller is used to connect the LED lamp or the light string in series, so as to The output voltage of the driving power supply controls the current of the LED lamp or the lamp string.

In some embodiments, the voltage detection module includes a first resistor and a second resistor, the first resistor and the second resistor are connected in series between the positive pole and the negative pole of the power supply, the first resistor The connection point between a resistor and the second resistor is the voltage output terminal of the voltage detection module.

In some embodiments, the current controller includes: a switch control circuit and at least one switch; the switch includes a controlled terminal and at least one pair of switch contacts, and the pair of switch contacts are used to communicate with the LED lamp or light strings in series; the switch control circuit includes a control terminal and a voltage input terminal, the voltage input terminal of the switch control circuit is connected to the voltage output terminal of the voltage detection module, and the control terminal of the switch control circuit is connected to the The controlled end of the switch is connected to control the duty cycle of the switch's opening and closing according to the output voltage of the driving power supply of the LED lamp or light string, so as to control the current of the LED lamp or light string.

In some embodiments, the switch control circuit includes a current setter, an error amplifier, and a switch driver; the current setter is used to set the corresponding current according to the voltage input to the current setter and output the corresponding current The set current, the voltage input end of the current setter is connected to the voltage output end of the voltage detection module, the current output end of the current setter is connected to the positive input end of the error amplifier; the The negative input terminal of the error amplifier is used to be connected to the current loop of the LED lamp or light string to sample the current of the LED lamp or light string; the output terminal of the error amplifier is connected to the input terminal of the switch driver, The driving end of the switch driver is connected to the controlled end of the switch to control the opening and closing of the switch.

In some embodiments, the switch control circuit includes a current setter, an error amplifier, and a switch driver; the current setter is used to set the corresponding current according to the voltage input to the current setter and output the corresponding current The set current, the voltage input end of the current setter is connected to the voltage output end of the voltage detection module, the current output end of the current setter is connected to the positive input end of the error amplifier; the The negative input terminal of the error amplifier is used to connect to the current loop of the LED lamp or light string to sample the current of the LED lamp or light string;

The output end of the error amplifier is connected to the input end of the switch driver, and the driving end of the switch driver is connected to the controlled end of the switch to control the opening and closing of the switch.

In some embodiments, the current controller further includes a smoothing circuit; the smoothing circuit is used to connect with the LED lamp or light string and connect it in series with the switch, so that when the switch is turned off, The smoothing circuit forms a path with the LED lamp or the lamp string, so that the stored energy supplies power to the LED lamp or the lamp string.

In some embodiments, the smoothing circuit includes a capacitor, a diode and an inductor; the inductor is connected in parallel with the capacitor in series with the diode, and the capacitor is used to be connected in parallel at both ends of the LED lamp or light string , the positive and negative poles of the diode are opposite to the current direction of the LED lamp or light string, and the inductance is used to be connected in series with the LED lamp or light string.

In some embodiments, the smoothing circuit includes a diode and an inductor connected in series with the diode, the inductor is used to be connected in series with the LED light or light string, and the diode is used to connect with the LED light or light string connected in series and parallel, and the positive and negative directions of the diodes are opposite to the current direction of the LED lights or light strings.

In some embodiments, the switch is a field effect transistor, the gate of the field effect transistor is connected to the control terminal of the switch control circuit, and the drain and the source are used to connect the LED lamp or lamp in series. In the current loop of the string, the current loop is broken or connected.

In another aspect, an embodiment of the present invention also provides an LED lighting system, including a driving power supply, at least one LED lamp or at least one string of LED lamps, and the LED dimming device provided by the embodiment of the present disclosure; the at least one LED The two ends of the lamp or at least one string of LED light strings are connected between the positive pole and the negative pole of the driving power supply; the voltage detection module of the LED dimming device is connected between the positive pole and the negative pole of the driving power supply, and the LED The current controller of the dimming device is connected with the at least one LED lamp or at least one string of LED lamps.

In some embodiments, the driving power supply includes one of an AC/DC switching power supply and a DC/DC switching power supply.

The embodiment of the present invention provides a current controller, which is connected in series with LED lamps or lamp strings, and detects the output voltage of the LED drive power supply through a voltage detection module, so as to use this output voltage as an instruction or control for constant current control Signal to control the current of the LED lamp, thereby controlling the brightness of the LED lamp.

The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the drawings and the following detailed description.

Description of drawings

In the drawings, unless otherwise specified, the same reference numerals designate the same or similar parts or elements throughout the several drawings. The drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in accordance with the present invention and should not be taken as limiting the scope of the present invention.

Fig. 1 shows a schematic diagram of an embodiment of an LED dimming device provided according to the present disclosure.

Fig. 2 shows a schematic diagram of an embodiment of an LED lighting system provided according to the present disclosure.

Fig. 3 shows a schematic diagram of an embodiment of an LED lighting system provided according to the present disclosure.

detailed description

In the following, only some exemplary embodiments are briefly described. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature and not restrictive.

Referring to FIG. 1 and FIG. 2 , FIG. 1 shows a schematic diagram of an LED dimming device according to an embodiment of the present invention. Fig. 2 shows a schematic diagram of an LED lighting system provided by an embodiment of the present disclosure. The LED dimming device 100 includes a voltage detection module 110 and a current controller 120 . The voltage detection module is used to connect between the positive pole and the negative pole of the LED driving power supply 210 of the LED lamp or light string 220 to sample the output voltage of the LED driving power supply 210 . The voltage input terminal of the current controller is connected to the voltage output terminal of the voltage detection module, and the current controller is used to connect the LED lamp or the lamp string 220 in series, so as to control the current of the LED lamp or the lamp string 220 according to the output voltage of the LED driving power supply . Applying the LED dimming device 100 in FIG. 1 to an LED system, the current on the LED lamp or lamp string 220 can be set as a function of the output voltage of the LED driving power supply 210 . If the output voltage of the LED driving power supply 210=V, and the LED current=I, then I=f(V). For example, I=aV+b. Wherein, a and b here are preset values, which can be set according to the average current value of the LED lamp or the lamp string 220 . Therefore, the embodiment of the present disclosure can directly adjust the light intensity of the LED lamp by adjusting the output voltage of the LED driving power supply.

For the situation that one LED driving power supply drives multiple parallel LED light strings at the same time, the light intensity of all LED light strings can be adjusted only by adjusting the output voltage of the driving power supply, and there is no need to set other related parameters.

Referring to FIG. 2 , an example of an LED light string in FIG. 2 will be taken as an example below to describe the embodiment of the present disclosure in detail. For multiple LED light strings 220 , each LED light string 200 can be equipped with a current controller 120 , and one LED driving power can be used for these multiple LED light strings. One current controller 120 can also control multiple LED light strings 220 . In addition, the voltage divider circuit composed of the first resistor R1 and the second resistor R2 connected in series can feed the output voltage of the LED driving power supply 210 to the current controller 120 as a reference, and the current controller 120 adjusts the output voltage according to the output voltage of the LED driving power supply 210 And stabilize the average current of the LED lamp string 220, so as to control or adjust the brightness of the LED lamp. The current of an LED lamp has an almost linear relationship with its light intensity. Therefore, in this embodiment, the LED lamps are dimmed by controlling the current of the LED lamp string 220 .

In the embodiments of the present disclosure, the voltage dividing circuit can be used as a voltage sensing circuit, and it can also implement voltage detection in other ways. When one LED driving power supply 210 drives a plurality of LED lamp strings 220, each LED lamp string 220 can install a current controller 120, and is connected in parallel with the LED driving power supply 210, then each current controller 120 senses the current of the LED driving power supply 210. The output circuit can come from the same sensing point of the same voltage divider circuit. Alternatively, each current controller 120 may also have its own independent voltage sensing circuit.

The LED driving power supply 210 can convert the power supply into a DC voltage with sufficient power to drive the LED lamp to emit light. The input of the LED driving power supply 210 can be AC or DC voltage, and the output is DC voltage to supply power for the LED lamp. LED driving power supply 210 can be any type of DC (direct current) power supply, such as linear power supply, AC/DC switching power supply, DC/DC switching power supply, PWM controlled switching power supply, buck or boost converter, LC or LRC resonator Any form of circuitry that can effectively provide sufficient power to the LED light string 220 .

The LED lighting system includes an LED driving power supply 210 , at least one LED light string 220 and an LED dimming device 100 . The LED driving power supply 210 can provide the LED light string 220 with a voltage that meets its power requirements. The current controller 120 in the LED dimming device 100 may include a switch control circuit 130 and at least one switch (a field effect transistor Q1 is taken as an example in FIG. 3 ). When a current controller 120 controls an LED light string 220 , a switch can be set in series with the LED light string 220 . When one current controller 120 controls multiple LED light strings 220, multiple switches can be set so that each LED light string 220 is connected to a switch respectively, so that one current controller 120 can control multiple LED light strings 220 current.

As shown in FIG. 3 , the switch control circuit 130 includes a current setter 131 , an error amplifier 132 and a switch driver 133 . The current setter 131 can set a current corresponding to the voltage value according to the input voltage value. The voltage input end of the current setter 131 is connected to the voltage output end of the voltage detection module, and the current output end of the current setter 131 is connected to the positive input end of the error amplifier 132 . At the same time, the negative input terminal of the error amplifier 132 can be connected in series with the LED light string 220 through a sampling resistor R3 to detect the current of the LED light string 220 . The error amplifier 132 amplifies the error of the current input from the positive input terminal and the negative input terminal. The amplified signal is output to the switch driver 133, and the switch driver 133 determines the duty cycle of the switch according to the amplified signal. Then, the opening and closing of the switch is controlled according to the duty ratio, so that the average current of the LED light string 220 meets the requirement.

In the embodiment of the present disclosure, a field effect transistor Q1 may be used as a switch. The gate of the field effect transistor Q1 is connected to the control terminal of the switch driver 133 , and the drain and the source are connected in series in the current loop of the LED light string 220 .

The field effect transistor Q1 is connected in series in the power supply circuit of the LED driving power supply 210 and the LED light string 220 , and serves as a power switch to control the working state of the power supply of the LED light string 220 on and off. The dimming device may also include a smoothing circuit 130 to smooth the voltage ripple generated at the moment of opening and closing of the switch. The field effect transistor Q1 cooperates with the smoothing circuit 130. When the field effect transistor Q1 is turned on, the current output by the LED drive power supply 210 can flow through the LED light string 220 and the smoothing circuit 130 from its anode, and the smoothing circuit 130 can be charged at this time to store electrical energy. When the field effect transistor Q1 is disconnected, the power supply circuit is disconnected, the LED drive power supply 210 will stop outputting current to the LED lamp string 220, the smoothing circuit 130 will form a path with the LED lamp string 220, and the energy stored in the smoothing circuit 130 will pass through the formed The path discharges to the LED light string 220, and the LED light string 220 can keep emitting light. Therefore, the average current flowing through the LED light string 220 can be well controlled by controlling the duty cycle of the power switch which is the field effect transistor Q1.

The smoothing circuit 130 may include a capacitor C1, an inductor L1 and a diode D1. The capacitor C1 is connected in parallel with the LED light string 220 , then connected in series with the inductor L1 , and then connected in parallel with the diode D1 . After the series branch of the LED light string 220 and the inductor L1 is connected in parallel with the diode D1, it is connected to the field effect transistor Q1. The direction of the current flowing from the drain to the source of the field effect transistor Q1 is the same as that of the LED light string 220 . When the field effect transistor Q1 is turned on, the current output by the LED driving power supply 210 passes through the two branches of the capacitor C1, the LED light string 220 and the inductor L1. After the capacitor C1 is charged, the output current of the LED driving power supply 210 no longer passes through the capacitor C1. At the moment when the field effect transistor Q1 is turned off, the LED drive power supply 210 no longer outputs current to the LED light string 220, the inductor L1 discharges to the LED light string 220 through the path formed by the diode D1 and the LED light string 220, and the capacitor C1 and the LED light string 220 form a The path also discharges the LED light string 220 . In addition, the smoothing circuit 130 composed of the capacitor C1, the inductor L1 and the diode D1 can also be used to smooth the voltage ripple generated when the field effect transistor Q1 is turned on and off.

The first resistor R1 and the second resistor R2 of the voltage divider circuit are connected in series between the positive pole and the negative pole of the LED driving power supply 210, providing a voltage detection point for the current controller 120 (the connection point of the first resistor R1 and the second resistor R2 ) to detect the output voltage of the LED driving power supply 210. When the output voltage of the LED driving power supply 210 changes, the voltage at the voltage detection point will also change accordingly, and the average current of the LED and the light intensity of the LED will also change accordingly. When the current controller 120 detects that the voltage at the voltage detection point changes, it adjusts the average current of the LED light string 220 to stabilize its current and light intensity.

The current setter 131 is connected to the positive input terminal of the voltage divider circuit and the error amplifier 132, and is used for converting the voltage signal at the voltage detection point into a corresponding current. Meanwhile, the negative input terminal of the error amplifier 132 is connected between the LED light string 220 and the negative pole of the power supply, so as to input the circuit of the LED light string 220 into the error amplifier 132 . The error amplifier 132 amplifies the error between the input currents of the positive input terminal and the negative input terminal, and controls the duty cycle of the field effect transistor Q1 through the switch driver 133 so that the average current of the LED light string 220 meets the requirements.

To sum up, the embodiment of the present disclosure provides a smoothing circuit 130 and a switch in the LED lighting system, and detects the change of the output voltage through the current control circuit to control the duty cycle of the switch, thereby adjusting or stabilizing the average current and light intensity of the LED.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present disclosure. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present disclosure, "plurality" means two or more, unless otherwise specifically defined.

The above is only a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any person skilled in the art can easily think of various changes or replacements within the technical scope of the present disclosure. These should all fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be determined by the protection scope of the claims.

Claims (10)

1. An LED dimming device, comprising: the device comprises a voltage detection module and a current controller;

the voltage detection module is used for being connected between the anode and the cathode of a driving power supply of the LED lamp or the lamp string so as to sample the output voltage of the driving power supply;

the voltage input end of the current controller is connected with the voltage output end of the voltage detection module, and the current controller is used for being connected with the LED lamp or the lamp string in series so as to control the current of the LED lamp or the lamp string according to the output voltage of the driving power supply.

2. The apparatus of claim 1, wherein the voltage detection module comprises a first resistor and a second resistor, the first resistor and the second resistor are connected in series for connection between a positive pole and a negative pole of the power supply, and a connection point between the first resistor and the second resistor is a voltage output terminal of the voltage detection module.

3. The apparatus of claim 1, wherein the current controller comprises: a switch control circuit and at least one switch;

the switch comprises a controlled end and at least one pair of switch contacts, and the pair of switch contacts is used for being connected with the LED lamp or the lamp string in series;

the switch control circuit comprises a control end and a voltage input end, the voltage input end of the switch control circuit is connected with the voltage output end of the voltage detection module, the control end of the switch control circuit is connected with the controlled end of the switch, and the on-off duty ratio of the switch is controlled according to the output voltage of the driving power supply of the LED lamp or the lamp string, so that the current of the LED lamp or the lamp string is controlled.

4. The apparatus of claim 3, the switch control circuit comprising a current setter, an error amplifier, and a switch driver;

the current setter is used for setting the current corresponding to the voltage input into the current setter and outputting the set current, the voltage input end of the current setter is connected with the voltage output end of the voltage detection module, and the current output end of the current setter is connected with the positive input end of the error amplifier;

the negative input end of the error amplifier is used for being connected to a current loop of the LED lamp or the lamp string so as to sample the current of the LED lamp or the lamp string;

the output end of the error amplifier is connected with the input end of the switch driver, and the driving end of the switch driver is connected with the controlled end of the switch so as to control the switch-off and switch-on of the switch.

5. The apparatus of claim 3, wherein the current controller further comprises a smoothing circuit; the smoothing circuit is used for being connected with the LED lamp or the lamp string and is connected with the switch in series after being connected, so that when the switch is disconnected, the smoothing circuit and the LED lamp or the lamp string form a passage, and the stored energy supplies power to the LED lamp or the lamp string.

6. The apparatus of claim 5, wherein the smoothing circuit comprises a capacitor, a diode, and an inductor; the inductor is connected with the diode in series and then connected with the capacitor in parallel, the capacitor is connected with two ends of the LED lamp or the lamp string in parallel, the directions of the anode and the cathode of the diode are opposite to the current direction of the LED lamp or the lamp string, and the inductor is connected with the LED lamp or the lamp string in series.

7. The apparatus of claim 5, wherein the smoothing circuit comprises a diode and an inductor connected in series with the diode, the inductor is connected in series with the LED lamp or light string, the diode is connected in parallel with the LED lamp or light string, and the direction of the positive and negative poles of the diode is opposite to the direction of the current of the LED lamp or light string.

8. The device according to any one of claims 3 to 7, wherein the switch is a field effect transistor, a gate of the field effect transistor is connected with a control end of the switch control circuit, and both a drain and a source are used for being connected in series in a current loop of the LED lamp or the light string to break or make the current loop.

9. An LED lighting system, comprising:

a drive power supply;

at least one LED lamp or at least one string of LED lamps;

the LED dimming device of any one of claims 1 to 8;

two ends of the at least one LED lamp or the at least one string of LED lamp strings are connected between the positive electrode and the negative electrode of the driving power supply;

the voltage detection module of the LED dimming device is connected between the positive electrode and the negative electrode of the driving power supply, and the current controller of the LED dimming device is connected with the at least one LED lamp or the at least one string of LED lamp strings.

10. The system of claim 9, wherein the power supply comprises one of an AC/DC switching power supply, a DC/DC switching power supply.

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