Dimming circuit, dimming power supply and LED lamp
By introducing adjustable shunt resistor modules connected in parallel to both ends of the light source in the dimming circuit, the existing dimming power supply has solved the problem of high cost and insufficient dimming depth, and the dimming depth is improved and the cost is reduced.
Patent Information
- Application Number
- CN202422026466.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-20
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-08-20
AI Technical Summary
Existing dimming power supplies have high cost problems in improving dimming depth, which is difficult to meet the market's demand for higher dimming depth.
By introducing a shunt resistor module into the dimming circuit, the module is connected in parallel to both ends of the light source, which can adjust the current shunt, thereby increasing the dimming depth without replacing the high-performance dimming BUCK chip.
It realizes the dimming depth performance indicators of dimming power without replacing high-performance chips. The circuit is simple, reliable, and low-cost. The resistance value of the shunt resistor module is adjustable, supporting the adjustability of dimming depth.
Smart Images
Figure CN222940936U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of dimming circuits, and particularly relates to a dimming circuit, a dimming power supply and an LED lamp. Background Art
[0002] Nowadays, higher requirements are put forward for the performance of dimming power supplies in the market. The dimming depth requirement is increased from 5% to 1%, and even increased to 0.1%, 0.01%, etc. The conventional method is to select a high-performance dimming BUCK chip to solve the problem of dimming depth, and the cost is relatively high. Summary of the Invention
[0003] The technical problem to be solved by the utility model is to provide a dimming circuit, a dimming power supply and an LED lamp, which can achieve the technical effect of improving the dimming depth performance index of the dimming power supply without replacing a high-performance dimming BUCK chip.
[0004] To solve the above technical problem, the utility model adopts the following technical scheme:
[0005] A dimming circuit includes: a dimming module for receiving a dimming control instruction and outputting a corresponding PWM signal; a DC dimming module for controlling the current flowing through a light source according to the PWM signal; a shunt resistance module connected in parallel with the light source, the resistance value of the shunt resistance module being adjustable for shunting the current flowing into the light source.
[0006] Preferably, the shunt resistance module includes an adjustable resistor and a current-limiting resistor, and the adjustable resistor and the current-limiting resistor are connected in series and then connected in parallel with the light source.
[0007] Preferably, the shunt resistance module includes at least two shunt resistors and a toggle switch, and the at least two shunt resistors are connected in parallel with the light source through the toggle switch.
[0008] Preferably, the shunt resistance module includes a first shunt resistor, a second shunt resistor and a toggle switch. One end of the first shunt resistor and one end of the second shunt resistor are respectively connected to one end of the light source, and the other end of the first shunt resistor and the other end of the second shunt resistor are connected to the other end of the light source through the toggle switch.
[0009] Preferably, the shunt resistance module includes a first shunt resistor, a second shunt resistor, a third shunt resistor and a toggle switch. One end of the first shunt resistor, one end of the second shunt resistor and one end of the third shunt resistor are respectively connected to one end of the light source, and the other end of the first shunt resistor, the other end of the second shunt resistor and the other end of the third shunt resistor are connected to the other end of the light source through the toggle switch.
[0010] Preferably, the light source is a light-emitting diode. The anode of the light-emitting diode is connected to the positive output terminal of a constant voltage source. The power supply pins of the dimming module and the DC dimming module are respectively connected to the positive output terminal of the constant voltage source. The PWM signal output pin of the dimming module is connected to the PWM signal input pin of the DC dimming module. The constant current output pin of the DC dimming module is connected to the cathode of the light-emitting diode.
[0011] Preferably, the DC dimming module includes a DC dimming chip. The power supply pin of the DC dimming chip is connected to the positive output terminal of the constant voltage source. The PWM signal input pin of the DC dimming chip is connected to the PWM signal output pin of the dimming module. The constant current output pin of the DC dimming chip is connected to the cathode of the light-emitting diode.
[0012] Preferably, a filter capacitor is connected in parallel at the output terminal of the constant voltage source.
[0013] Preferably, the intelligent mobile terminal is a mobile phone or a tablet.
[0014] A dimming power supply includes the dimming circuit described above.
[0015] An LED lamp includes the dimming circuit or the dimming power supply described above.
[0016] The beneficial technical effects of the present invention are as follows: The above dimming circuit includes a shunt resistor module. The shunt resistor module is connected in parallel across the light source to shunt a part of the current flowing through the light source, reducing the current flowing through the light source. Without replacing a high-performance and high-cost dimming BUCK chip, the technical effect of improving the dimming depth performance index of the dimming power supply can be achieved. The circuit is simple, reliable, and low in cost. Moreover, the resistance value of the shunt resistor module connected in parallel across the light source is adjustable, and the dimming depth can be adjusted by adjusting the resistance value of the shunt resistor module. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is the circuit schematic diagram of the dimming circuit of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] To make the purposes, technical solutions, and advantages of the present invention clearer to those of ordinary skill in the art, the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0019] The present invention provides a dimming circuit.
[0020] As Figure 1As shown in the figure, in an embodiment of the present utility model, the dimming circuit includes a dimming module 10, a DC dimming module 20, and a shunt resistor module 30; the dimming module 10 is configured to receive a dimming control instruction and output a corresponding PWM signal; the DC dimming module 20 controls the current flowing through the light source 40 according to the PWM signal; the shunt resistor module 30 is connected in parallel with the light source 40, and the resistance value of the shunt resistor module is adjustable, and is used for shunting the current flowing into the light source 40.
[0021] In this embodiment, the dimming module 10 can be wirelessly Bluetooth-connected to intelligent mobile terminals such as mobile phones and tablets. Its main function is to receive the dimming control instruction sent by the user through the APP on the intelligent mobile terminal, and adjust the duty cycle of the PWM signal according to the received dimming control instruction to control the dimming circuit. The dimming module 10 can adopt the dimming modules currently sold on the market. The second pin of the dimming module 10 is the power supply pin, which is connected to the positive terminal (VIN+) of the output of the constant voltage source; the third pin of the dimming module 10 is the ground pin; the first pin of the dimming module 10 is the PWM signal output pin, which is used to output PWM signals with different duty cycles to the DC dimming module to control the dimming circuit. In other embodiments, the dimming module 10 can also be wirelessly connected to the control terminal through different wireless modules such as WiFi, ZigBee, 2.4G, and 433M, and is used to receive the dimming control instruction sent by the user through the control terminal, and adjust the duty cycle of the PWM signal according to the received dimming control instruction to control the dimming circuit.
[0022] The light source 40 includes a light-emitting diode D1. The anode of the light-emitting diode D1 is connected to the positive terminal (VIN+) of the output of the constant voltage source. The power supply pins of the dimming module 10 and the DC dimming module 20 are respectively connected to the positive terminal of the output of the constant voltage source. The PWM signal output pin of the dimming module 10 is connected to the PWM signal input pin of the DC dimming module 20. The constant current output pin of the DC dimming module 20 is connected to the cathode of the light-emitting diode D1.
[0023] The DC dimming module 20 includes a DC dimming chip U1. The power supply pin (the second pin) of the DC dimming chip U1 is connected to the positive terminal (VIN+) of the output of the constant voltage source. The PWM signal input pin (the third pin) of the DC dimming chip U1 is connected to the PWM signal output pin of the dimming module 10. The constant current output pin (the first pin) of the DC dimming chip U1 is connected to the cathode of the light-emitting diode. The fourth pin of the DC dimming chip U1 is grounded. The DC dimming chip U1 can adopt a DC dimming chip with a model number of DIO8280 or other models.
[0024] The dimming circuit further includes a filter capacitor EC1, which is connected in parallel to the output terminal of the constant voltage source. That is, one end of the filter capacitor EC1 is connected to the positive pole (VIN+) of the output terminal of the constant voltage source, and the other end is grounded.
[0025] In this embodiment, the shunt resistance module 30 includes a shunt resistor R1, a shunt resistor R2, and a toggle switch S1. One end of the shunt resistor R1 and one end of the shunt resistor R2 are respectively connected to one end of the light source 40. The other end of the shunt resistor R1 and the other end of the shunt resistor R2 are connected to the other end of the light source 40 through the toggle switch S1. The shunt resistance module 30 is connected in parallel across the two ends of the light source 40, which can shunt the current flowing into the light source 40, reduce the current flowing through the light source 40, and improve the dimming depth. By switching control of the toggle switch S1, the resistance value of the resistor connected in parallel across the two ends of the light source 40 can be adjusted to achieve adjustable dimming depth. In some other embodiments of the present invention, the shunt resistance module 30 includes a plurality of shunt resistors and a toggle switch. The number of shunt resistors can be 3, 4, or other numbers. The plurality of shunt resistors are connected in parallel to the light source 40 through the toggle switch. In some other embodiments of the present invention, the shunt resistance module 30 includes a variable resistor and a current-limiting resistor. The variable resistor and the current-limiting resistor are connected in series and then connected in parallel to the light source 40. By adjusting the variable resistor, the resistance value of the resistor connected in parallel across the two ends of the light source 40 can be adjusted.
[0026] The working principle of the dimming circuit in this embodiment is as follows:
[0027] When the power is turned on, the dimming module 10 and the DC dimming module 20 work normally. The first pin of the dimming module 10 outputs a PWM signal to the third pin of the DC dimming module 20. The DC dimming module 20 outputs a corresponding current to the light source 10 according to the duty cycle of the input PWM signal. At this time, the toggle switch S1 is in the off state, and the shunt resistors R1 and R2 are open and not in the working state. If the dimming control instruction is input through the mobile phone APP at this time to adjust the duty cycle of the PWM signal output by the first pin of the dimming module 10, so that the first pin of the DC dimming module 20 outputs the minimum current (this current is limited by the accuracy of the DC dimming chip U1). For example, the output minimum current is 5 mA, and the dimming depth of this power supply = 5 / output maximum current * 100%. For example, if the output maximum current is 500 mA, then the dimming depth of this power supply is (5 mA / 500 mA * 100% = 1%) 1%. We can increase the resistance value of the resistor connected in parallel across the two ends of the light source 40 through the toggle switch S1, shunt the current flowing through the light source 40, and improve the overall dimming depth of the power supply.
[0028] Assume that the light source voltage is 30V at this time and the current flowing through the light source 40 is 5mA. We need to increase the dimming depth of this power supply to 0.5% or 0.1%. At a dimming depth of 0.5%, it can be calculated that the minimum current flowing through the light source 40 is 500mA * 0.5% = 2.5mA. Then, a shunt current of 5mA - 2.5mA = 2.5mA is required. The resistance R1 to be connected in parallel is 30V / (the minimum output current of the DC dimming chip 5mA - the minimum current flowing through the light source 2.5mA) = 12KΩ. At a dimming depth of 0.1%, it can be calculated that the minimum current flowing through the light source 40 is 500mA * 0.1% = 0.5mA. The resistance R to be connected in parallel is 30V / (the minimum output current of the DC dimming chip 5mA - the minimum current flowing through the light source 0.5mA) = 6.6KΩ. 6.6KΩ is the resistance value of the parallel connection of resistor R1 and resistor R2. It is calculated that R2 = 15KΩ.
[0029] When the toggle switch S1 is unplugged to connect the 2nd and 3rd pins of the toggle switch S1, the resistor R1 is connected in parallel across the two ends of the light source 40, shunting 2.5mA of the 5mA current output from the 1st pin of the DC dimming chip U1 to the resistor R1. At this time, the current flowing through the light source 40 is 5mA - the current flowing through the resistor R1 2.5mA = 2.5mA. The minimum dimming depth of the current power supply output reaches 2.5 / the maximum current 500mA output from the 1st pin of the DC dimming chip * 100% = 0.5%. If the 1st and 4th pins of the toggle switch S1 are also connected, the resistor R1 and the resistor R2 are simultaneously connected in parallel across the two ends of the light source 40, shunting 4.5mA of the 5mA current output from the 1st pin of the DC dimming chip U1 to the resistor R1 and the resistor R2. At this time, the current flowing through the light source 40 is 5mA - the shunt current of R2 and R1 4.5mA = 0.5mA. The minimum dimming depth of the current power supply output reaches 0.5 / the maximum current 500mA output from the 1st pin of the DC dimming chip * 100% = 0.1%. By combining and connecting the resistor R1 and the resistor R2 in parallel across the two ends of the light source 40 through the toggle switch S1, the current flowing through the light source 40 is redistributed, achieving the technical effect of reducing the current flowing through the light source 40 and increasing the overall dimming depth of the power supply.
[0030] The beneficial technical effects of the present utility model are as follows: The dimming circuit of the present utility model includes a shunt resistor module, which is connected in parallel across the two ends of the light source, shunting a part of the current flowing through the light source, reducing the current flowing through the light source. Without replacing a high-performance and high-cost dimming BUCK chip, the technical effect of improving the dimming depth performance index of the dimming power supply can be achieved. The circuit is simple, reliable, and low-cost; moreover, the resistance value of the shunt resistor module connected in parallel across the two ends of the light source is adjustable, and the dimming depth can be adjusted by adjusting the resistance value of the shunt resistor module.
[0031] Based on Figure 1For the dimming circuit in the illustrated embodiment, the present invention also provides a dimming power supply, which includes Figure 1 the dimming circuit in the illustrated embodiment.
[0032] The present invention also provides an LED lamp, which includes Figure 1 the dimming circuit in the illustrated embodiment or the dimming power supply described above.
[0033] The above are only the preferred embodiments of the present utility model, and do not impose any formal limitations on the present utility model. Those skilled in the art can make various equivalent changes and improvements on the basis of the above embodiments. Any equivalent changes or modifications made within the scope of the claims shall fall within the protection scope of the present utility model.
Claims
1. A dimming circuit, characterized in that: include: A dimming module, used to receive dimming control instructions and output corresponding PWM signals; A DC dimming module, controlling the current flowing through the light source according to the PWM signal; A shunt resistor module is connected in parallel with the light source. The resistance of the shunt resistor module is adjustable and is used to shunt the current flowing into the light source.
2. The dimming circuit according to claim 1, characterized in that: The shunt resistor module includes an adjustable resistor and a current-limiting resistor. The adjustable resistor and the current-limiting resistor are connected in series and then in parallel with the light source.
3. The dimming circuit according to claim 1, characterized in that: The shunt resistor module includes at least two shunt resistors and a shift switch, and the at least two shunt resistors are connected in parallel with the light source through the shift switch.
4. The dimming circuit according to claim 1, characterized in that: The shunt resistor module includes a first shunt resistor, a second shunt resistor and a toggle switch. One end of the first shunt resistor and one end of the second shunt resistor are respectively connected to one end of the light source, and the other end of the first shunt resistor and the other end of the second shunt resistor are connected to the other end of the light source through the toggle switch.
5. The dimming circuit according to claim 1, characterized in that: The shunt resistor module includes a first shunt resistor, a second shunt resistor, a third shunt resistor and a toggle switch. One end of the first shunt resistor, one end of the second shunt resistor, and one end of the third shunt resistor are respectively connected to one end of the light source, and the other end of the first shunt resistor, the other end of the second shunt resistor, and the other end of the third shunt resistor are connected to the other end of the light source through the toggle switch.
6. The dimming circuit according to any one of claims 1 to 5, characterized in that: The light source adopts a light-emitting diode, the anode of the light-emitting diode is connected to the positive output terminal of the constant voltage source, the power supply pin of the dimming module and the power supply pin of the DC dimming module are respectively connected to the positive output terminal of the constant voltage source, the PWM signal output pin of the dimming module is connected to the PWM signal input pin of the DC dimming module, and the constant current output pin of the DC dimming module is connected to the cathode of the light-emitting diode.
7. The dimming circuit according to claim 6, characterized in that: The DC dimming module includes a DC dimming chip, a power supply pin of the DC dimming chip is connected to the positive output terminal of the constant voltage source, a PWM signal input pin of the DC dimming chip is connected to the PWM signal output pin of the dimming module, and a constant current output pin of the DC dimming chip is connected to the cathode of the light-emitting diode.
8. The dimming circuit according to claim 7, characterized in that: The output end of the constant voltage source is connected in parallel with a filter capacitor.
9. A dimming power supply, characterized in that: The invention comprises a dimming circuit as described in any one of claims 1 to 8.
10. An LED lamp, characterized in that: It comprises the dimming circuit as described in any one of claims 1 to 8 or the dimming power supply as described in claim 9.