CN210157440U - A kind of LED lamp circuit device with adjustable color temperature - Google Patents

Abstract

The utility model discloses an LED lamp circuit device with adjustable color temperature, which includes at least two groups of LED lamp bead groups, each group is connected in series with at least one LED lamp bead, and the two groups of LED lamp bead groups use LED lamp beads of different color temperatures; wherein the two groups of LED lamp bead groups are connected in series, and a variable shunt circuit unit is connected in parallel to any selected group of LED lamp bead groups, for ensuring that the current change rate flowing through the two groups of LED lamp beads is different. The LED lamp circuit device with adjustable color temperature of the utility model adopts a method of connecting two groups of LED lamp bead groups with different color temperatures in series, thereby realizing different current change ratios of the two groups of LED lamp groups, so that there is no need to equip each LED lamp bead group with a driving circuit unit, thereby achieving a simpler circuit, easier control, and lower development cost.

Description

A kind of LED lamp circuit device with adjustable color temperature

technical field

The utility model relates to a circuit improvement, in particular to an LED lamp circuit device with adjustable color temperature.

Background technique

The prior art LED color temperature regulation (also known as Dim-To-Warm, Warm-Dimming, Dim-Tone, TunableWhite, etc.) is to control the current of two or more groups of LED lamp beads with different color temperatures. The brightness ratio of LED lamp beads or lamp bead groups, so as to achieve the purpose of changing the color temperature. LED lights with different color temperatures will have different feelings of cool and warm, for example, white light and blue light are cool colors, while yellow and red lights are warm colors. Using at least two sets of LED lamp beads or lamp bead groups with different color temperatures, for example, it can be composed of cold light white and warm yellow light, or warm light (yellow light) lamp beads with different color temperatures.

At present, the common LED lamps with adjustable color temperature are mostly realized by connecting at least two groups of LED lamps or lamp groups in parallel. The current of the LED lamp beads in the group changes the ratio of the brightness to achieve the effect of changing the color temperature.

As shown in FIG. 1 , in the prior art adjustable color temperature LED lamp or lamp group circuit, two groups of lamp bead strings with different color temperatures, namely the white light lamp bead string 110 and the yellow light lamp bead string 120 are connected in parallel. , which respectively correspond to their own driving circuits, and the driving circuits can set corresponding driving circuits according to different dimming methods, such as thyristor dimming, digital signal dimming, adjustable current sources, etc.; It includes a white light driving unit 130 and a warm light driving unit 140, which respectively drive the parallel white light bulb string 110 and the yellow light bulb string 120 to change the brightness of the white light bulb, and at the same time change the yellow light bulb string at different rates through the warm light driving circuit The current of the two groups is adjusted so that the brightness of the two groups of lamp beads changes in different proportions, so that the entire LED lamp will display different color temperatures.

However, this solution in the prior art requires a single drive circuit (such as an adjustable current source) to achieve color temperature adjustment. It is necessary to set up an independent drive circuit unit for each group of lamp beads, and adjust the current at different rates to adjust the color temperature. In this way, not only each group of lamp beads needs a drive circuit unit, but also coordinated control between different groups of lamp bead drive circuit units, which not only increases the realization cost of the product, but also increases the development cost and development time. more complicated.

Therefore, the existing technology still needs to be improved and developed.

Utility model content

The purpose of the present invention is to provide an LED lamp circuit device with adjustable color temperature, aiming at the high cost of multiple drive circuit units in the prior art, and to realize the realization of the adjustable color temperature circuit with lower cost of the drive circuit unit. Program.

The technical scheme of the present utility model is as follows:

An LED lamp circuit device with adjustable color temperature, which comprises at least two groups of LED lamp beads, each group is connected in series with at least one LED lamp bead, and the two groups of LED lamp beads use LED lamp beads with different color temperatures; wherein, The two groups of LED lamp beads are connected in series, and a variable shunt circuit unit is connected in parallel to any selected group of LED lamp bead groups to ensure that the currents flowing through the two groups of LED lamp beads have different rates of change.

The LED lamp circuit device with adjustable color temperature, wherein the variable shunt circuit unit is realized by an N-type field effect transistor, and the source and drain of the N-type field effect transistor are respectively connected to the selected The two ends of the lamp bead group are connected to the two ends of the two groups of lamp bead groups through a voltage dividing resistor circuit.

The LED lamp circuit device with adjustable color temperature, wherein a Zener diode is connected in parallel with the voltage dividing resistor circuit, and the negative terminal of the Zener diode is connected to two groups of LED lamps through a third load resistor The positive extreme of the bead group.

The LED lamp circuit device with adjustable color temperature, wherein a zener diode is connected in parallel with the voltage dividing resistor circuit, and the negative terminal of the zener diode is connected to two groups of LED lamp beads through a third load resistor between the groups and electrically connected to the drain of the N-type field effect transistor.

The LED lamp circuit device with adjustable color temperature, wherein a load resistor is respectively connected between the grid of the N-type field effect tube and the positive electrode and the negative electrode of the Zener diode, including a fourth connection connecting the negative electrode. Load circuit and fifth load resistor connected to positive.

The LED lamp circuit device with adjustable color temperature, wherein a load is respectively connected between the negative electrode of the two LED lamp bead groups, the positive electrode of the Zener diode and the source electrode of the N-type field effect transistor. The resistor includes a first load resistor connected to the anode of the Zener diode and a second load resistor connected to the source.

In the described LED lamp circuit device with adjustable color temperature, the LED lamp beads on the two groups of LED lamp bead groups are arranged in the same quantity and the same specification.

The LED lamp circuit device with adjustable color temperature provided by the utility model adopts the method of connecting two sets of LED lamp bead groups with different color temperatures in series, and by connecting one of the LED lamp bead groups in parallel with one Variable shunt circuit unit, so as to achieve different ratios of current changes in the two LED lamp groups, so there is no need to equip each LED lamp bead group with a drive circuit unit, so as to achieve simpler circuits, easier control, and lower development costs. Low.

Description of drawings

FIG. 1 is a schematic diagram of a connection structure of a circuit with adjustable color temperature in the prior art.

FIG. 2 is a schematic diagram of the principle scheme of the LED lamp circuit device with adjustable color temperature according to the present invention.

FIG. 3 is a specific schematic diagram of the principle scheme of the LED lamp circuit device with adjustable color temperature according to the present invention.

4 is a schematic diagram of a first preferred embodiment of the LED lamp circuit device with adjustable color temperature according to the present invention.

5 is a schematic diagram of a second preferred embodiment of the LED lamp circuit device with adjustable color temperature according to the present invention.

FIG. 6 is a schematic diagram showing the specific principle of the LED lamp circuit device with adjustable color temperature according to the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below.

A preferred embodiment of an LED lamp circuit device with adjustable color temperature disclosed by the present invention is shown in FIG. 2 , which includes at least two groups of LED lamp beads, which are set as the first group of LED lamp beads for the convenience of description. The group 210 and the second group of LED lamp bead groups 220, each of which is connected in series with at least one LED lamp bead, specifically, the LED lamp bead is a light-emitting diode, so each group of LED lamp bead groups is composed of one or more LED lamp beads according to Connect in series in the same polarity direction. Moreover, the two groups of LED lamp beads adopt LED lamp beads with different color temperatures, and the two groups of LED lamp bead groups are connected in series, that is, the first group and the second group of LED lamp bead groups are also connected in series according to the same polarity direction. On any group of selected LED lamp bead groups, specifically in this preferred embodiment, a variable shunt circuit unit 230 is connected in parallel with the second group of LED lamp bead groups 220 , and the variable shunt circuit unit 230 is connected in parallel. It can be used to ensure and realize that the rate of change of the current flowing through the two groups of LED lamp beads is different, so that the current changes between the two groups of LED lamp bead groups can be asynchronous, so as to realize the two groups of LED lamp beads with different color temperatures. The current of the group is adjusted in different proportions.

The key point of the present invention is to connect the LED lamp bead groups in series and connect the variable shunt circuit in parallel to achieve the purpose. The variable shunt circuit can be freely connected to any group or any position of the LED lamp beads, as long as the shunt purpose is achieved. In different embodiments of the present invention, the number and specifications of each LED lamp bead group may be different, and different combinations may be designed according to different specific effect requirements.

Through the series connection of the first group and the second group of LED lamp bead groups, the circuit of the present invention can use one driving circuit unit to drive the first group and the second group of LED lamp bead groups, and the variable shunt circuit The differentiated current control of the unit 230 realizes the control of different current change rates on the two groups of lamp beads, thereby realizing different changes in color temperature and brightness, and finally realizing the adjustable and controllable color temperature.

As shown in FIG. 2 and FIG. 3 , in the two preferred embodiments of the LED lamp circuit device with adjustable color temperature according to the present invention, the variable shunt circuit unit 230 can be realized by an N-type field effect transistor circuit, The source and drain of the N-type field effect transistor Q1 used are respectively connected to both ends of the second group of lamp beads (any group of LED lamp bead groups can be selected), and the gate of the N-type field effect transistor Q1 is connected to the two ends of the second group of lamp beads. Connect to both ends of the two sets of lamp beads, that is, both ends of the entire series circuit. As shown in Figure 3, the module A is an electronic switch circuit, which can be a triode, a field effect transistor, a BJT (bipolar transistor) or other electronic components and switch circuits. The simplest function of the variable shunt circuit unit is to use the resistance circuit control module A to realize shunt.

Although the simple circuit shown in FIG. 3 can achieve the basic purpose of the present invention, the stability of its shunt is not high. Therefore, as shown in FIG. 6 , in the schematic diagram of the preferred circuit principle of the present invention, the The module B of the voltage regulator circuit adds a voltage regulator circuit to the resistance circuit of the voltage divider, which can improve the stability of the shunt, and the visual effect will be better when the color temperature is changed. The simplest way of realizing the voltage stabilizing circuit is a zener diode, of course, other voltage stabilizing components and voltage stabilizing circuits can also be used.

As shown in FIG. 4 and FIG. 5 , a zener diode circuit is connected in parallel with the voltage dividing resistor circuit of the gate of the N-type field effect transistor. Through the circuit cooperation of the N-type field effect transistor Q1 and the Zener diode D1, the function of stable current change can be realized.

It should be understood that, in the preferred embodiment of the present invention, the variable shunt circuit unit is not limited to be realized by N-type field effect transistors, and any other electronic switches such as P-type field effect transistors or BJTs or IGBTs can also achieve For the purpose of variable shunt, its corresponding circuit implementation can refer to the preferred embodiments of the present invention, which is an implementation scheme that can be understood by those of ordinary skill in the art without creative work.

Specifically, the negative terminal of the Zener diode circuit D1 can be connected to the positive terminal of the first group of LED lamp beads 210 through a third load resistor R3, that is, away from the second group of LED lamp bead groups 220 one end of the connection, as shown in Figure 3. Alternatively, the negative terminal of the Zener diode circuit D1 is connected to the positive terminal of the second group of LED lamp beads 220 through the third load resistor R3, that is, the one connected to the first group of LED lamp bead groups 210 One terminal is electrically connected to the drain of the N-type field effect transistor Q1.

In a preferred embodiment of the LED lamp circuit device with adjustable color temperature according to the present invention, a load is respectively connected between the gate of the N-type field effect transistor Q1 and the positive and negative electrodes of the Zener diode D1 Resistors, namely the fourth load circuit R4 connected to the negative electrode and the fifth load resistor R5 connected to the positive electrode, the Zener diode circuit includes the Zener diode D1, the fourth load resistor R4 and the fifth load resistor R5 .

A load resistor is respectively connected between the negative electrode of the second LED lamp bead group 220 and the positive electrode of the Zener diode D1 and the source of the N-type field effect transistor Q1, that is, the positive electrode of the Zener diode is connected. A first load resistor R1 and a second load resistor R2 connected to the source. In the circuit of the present invention, the LED lamp beads on the first group of LED lamp bead groups and the second group of LED lamp bead groups are arranged with the same specification and the same number, so that the symmetrical circuit is convenient for setting and function control. processing. At the same time, the number and ratio of the lamp beads of the two LED lamp bead groups can be changed according to the actual product needs to suit the needs of different uses.

The working principle of the circuit of the present invention is to connect the drive circuit units, such as an adjustable current source, in series through two sets of LED lamp bead groups with different color temperatures, and one of the LED lamp bead groups is connected to a variable shunt circuit, such as this In a preferred embodiment, the second LED lamp bead group 220 is connected. When the currents flowing through the first group and the second group of LED lamp bead groups are changed, the resistance value of the variable shunt circuit also changes, thereby changing the current flowing through the variable shunt circuit and flowing through the second group. Therefore, the current of the LED lamp bead group 220 is different from the current flowing through the first group of LED lamp bead groups 210 , and the brightness change ratio of the two groups of lamp bead groups will be changed differently, so that the color temperature can be adjusted.

At present, the common driving circuits on the market generally have the function of "Under Voltage Protection" (Under Voltage Protection). The current shunt on the lamp bead series structure will easily cause the LED voltage to be too low, thus causing the driving circuit to enter the low voltage protection mode or Other abnormal working modes, in this case, the entire LED light product will flicker or other abnormal and unstable phenomena.

In order to solve the above difficulties, the variable shunt circuit needs to meet the following conditions: on the one hand, when the main driving current changes, the variable shunt circuit needs to adjust the current flow by itself to perform shunt, so as to achieve the effect of changing the color temperature; When the pearlescent brightness is dimmed, the drive current and voltage will decrease. When the voltage drops close to the drive circuit low-voltage protection mode (or other abnormal operating modes), the variable shunt circuit needs to adjust the current by itself to prevent the drive circuit from entering the protection mode.

In the above circuit of the present invention, the difference between the two preferred embodiments is that the negative electrode of the Zener diode D1 is directly connected to the positive electrode of the driving circuit unit through the third load resistor R3 (that is, The positive terminal of the first group of LED lamp bead groups) is still connected to the connection point between the first group of LED lamp bead groups and the second group of LED lamp bead groups. After passing through the third load resistor R3, the driving circuit unit provides power to the Zener diode D1 to establish a stable voltage. The fourth load resistor and the fifth load resistor provide the Vgs voltage (ie the voltage between the gate and the source) to the N-type field effect transistor Q1.

When the driving current is the largest, the brightness of the two LED lamp bead groups is the largest, and the voltage difference between the two ends of the first load resistor R1 is the highest, so that the effective Vgs voltage of the N-type field effect transistor Q1 is the lowest, and the N-type field effect transistor Q1 will be turned off, there is no current shunt, the current of the first group of LED lamp bead groups 210 and the second group of LED lamp bead groups 220 are the same, and the color temperature is fixed.

When the brightness of the overall LED lamp is lowered, the voltage difference across the first load resistor decreases due to the reduction of the driving current, and the effective Vgs voltage of the N-type field effect transistor Q1 increases, so that the N-type field effect transistor Q1 is turned on. , the current flowing through the second group of LED lamp beads 220 will be shunted to the N-type field effect transistor Q1. Therefore, the current flowing through the two groups of lamp beads will decrease at different rates. The first group of LED lamp beads The brightness of the group 210 and the second group of LED lamp bead groups 220 will also decrease at different rates, so the ratio of the brightness of the two groups of lamp bead groups will change accordingly, thereby changing the color temperature. And vice versa to the maximum current.

When the driving current is further changed, the effective Vgs voltage of the N-type field effect transistor Q1 will change accordingly, and the current of the second group of LED lamp beads 220 will also be different from the first group of LED lamp bead groups 210 The rate of change, thus finally realizing the color temperature adjustment.

When the brightness of the overall LED lamp bead continues to dim, the driving current continues to decrease, which will cause the positive and negative voltages of the driving circuit to decrease, and the effective Vgs voltage provided by the third load resistor will also decrease, flowing through the N-type field effect. The current of tube Q1 will also decrease, even causing Q1 to turn off and stop shunting. In this way, the drive circuit can be prevented from entering the low-voltage protection protection mode to maintain the normal operation and stability of the LED lamp beads.

In the above-mentioned technical implementation scheme of the present invention, the series connection of two LED lamp bead groups and the variable shunt circuit unit solves the technical difficulty of series connection, and a single LED driving circuit unit, such as an adjustable current unit, can be used. source, greatly reducing development time and cost. Compared with the parallel scheme in the prior art, the series scheme can use fewer lamp beads, the drive circuit of the product is simpler to implement, fewer parts are required, and the production process is also easier, which reduces the production cost.

It should be understood that, for those skilled in the art, improvements or transformations can be made according to the above description, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (7)

1. A color temperature adjustable LED lamp circuit device comprises at least two groups of LED lamp bead groups, wherein each group is connected in series with at least one LED lamp bead, and the two groups of LED lamp bead groups adopt LED lamp beads with different color temperatures; the LED lamp bead set is characterized in that the two groups of LED lamp bead sets are connected in series, and a variable shunt circuit unit is connected in parallel to any selected one of the two groups of LED lamp bead sets and used for ensuring that the current change rates flowing through the two groups of LED lamp beads are different.

2. The LED lamp circuit device capable of adjusting the color temperature according to claim 1, wherein the variable shunt circuit unit is implemented by an N-type field effect transistor, a source electrode and a drain electrode of the N-type field effect transistor are respectively connected to two ends of the selected group of LED lamp bead groups, and a grid electrode of the N-type field effect transistor is connected to two ends of the two groups of LED lamp bead groups through a voltage dividing resistor circuit.

3. The LED lamp circuit device with the adjustable color temperature according to claim 2, wherein a voltage regulator diode is connected in parallel to the voltage dividing resistor circuit, and a negative terminal of the voltage regulator diode is connected to positive terminals of the two groups of LED lamp beads through a third load resistor.

4. The color temperature adjustable LED lamp circuit device according to claim 2, wherein a voltage regulator diode is connected in parallel to the voltage divider resistor circuit, and a negative terminal of the voltage regulator diode is connected to a positive terminal of the second group of LED lamp bead groups, i.e. one terminal connected to the first group of LED lamp bead groups, through a third load resistor, and is electrically connected to a drain of the N-type field effect transistor.

5. The color temperature adjustable LED lamp circuit device according to claim 3 or 4, wherein load resistors are respectively connected between the grid of the N-type field effect transistor and the positive electrode and the negative electrode of the voltage regulator diode, and the load resistors comprise a fourth load circuit connected with the negative electrode and a fifth load circuit connected with the positive electrode.

6. The LED lamp circuit device capable of adjusting the color temperature according to claim 5, wherein load resistors are respectively connected between the negative electrodes of the two groups of LED lamp bead groups and the positive electrode of the voltage regulator diode and the source electrode of the N-type field effect transistor, and the load resistors comprise a first load resistor connected with the positive electrode of the voltage regulator diode and a second load resistor connected with the source electrode.

7. The color temperature adjustable LED lamp circuit device according to claim 6, wherein the LED lamp beads in the two LED lamp bead groups are arranged in the same number with the same specification.

Images