Color temperature setting circuit of LED lamp

Abstract

The utility model discloses a color temperature setting circuit of an LED lamp, which comprises a high color temperature LED circuit, a low color temperature LED circuit, a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistance setting circuit and a voltage stabilizing circuit, the voltage sampling circuit generates corresponding voltage output based on the smaller one of the voltages provided by the first current control circuit and the second current control circuit and a voltage threshold value, and the resistance setting circuit sets resistance values for the first current control circuit and the second current control circuit. The first current control circuit generates corresponding current to drive the high color temperature LED circuit to emit light according to the voltage output by the voltage sampling circuit and the resistance value set by the resistance setting circuit; the second current control circuit generates corresponding current to drive the low-color-temperature LED circuit to emit light according to the voltage output by the voltage sampling circuit and the resistance value set by the resistance setting circuit; the device has the advantages of high mixed light color temperature setting precision and no stroboflash phenomenon.

Description

Technical Field

[0001] The utility model relates to a color temperature setting circuit, in particular to a color temperature setting circuit for an LED lamp. Background Art

[0002] LED lamps capable of setting color temperature have been widely used because they can emit light of different color temperatures to meet the usage requirements of different user groups. An LED lamp capable of setting color temperature usually includes a color temperature setting circuit, which has a positive electrode and a negative electrode. When a current is applied between the positive electrode and the negative electrode of the color temperature setting circuit, the color temperature setting circuit emits light. Existing color temperature setting circuits mainly include a high-color-temperature LED circuit and a low-color-temperature LED circuit, and both the high-color-temperature LED circuit and the low-color-temperature LED circuit have a positive electrode and a negative electrode. When a current is applied between the positive electrode and the negative electrode of the high-color-temperature LED circuit, the high-color-temperature LED circuit emits high-color-temperature light, and its luminous intensity is proportional to the magnitude of the current applied between its positive electrode and negative electrode; when a current is applied between the positive electrode and the negative electrode of the low-color-temperature LED circuit, the low-color-temperature LED circuit emits low-color-temperature light, and its luminous intensity is proportional to the magnitude of the current applied between its positive electrode and negative electrode. When the high-color-temperature LED circuit and the low-color-temperature LED circuit emit light simultaneously, the color temperature setting circuit emits a mixed light formed by the high-color-temperature light and the low-color-temperature light, and the color temperature of the mixed light corresponds to the ratio of the luminous intensity of the high-color-temperature light to the luminous intensity of the low-color-temperature light. The ratio of the luminous intensity of the high-color-temperature light to the luminous intensity of the low-color-temperature light corresponds to the ratio of the currents applied to the high-color-temperature LED circuit and the low-color-temperature LED circuit. By setting the ratio of the currents applied to the high-color-temperature LED circuit and the low-color-temperature LED circuit, the luminous intensity of the mixed light, i.e., the luminous color temperature, can be set.

[0003] Currently, a color temperature setting circuit for high-precision color temperature setting drives the high-color-temperature LED circuit and the low-color-temperature LED circuit to emit light by means of a PWM signal in a time-sharing manner. If, when the PWM signal is at a high level, the total current applied to the color temperature setting circuit drives the high-color-temperature LED circuit to emit light, then when the PWM signal is at a low level, the low-color-temperature LED circuit is driven to emit light. Conversely, if, when the PWM signal is at a high level, the total current applied to the color temperature setting circuit drives the low-color-temperature LED circuit to emit light, then when the PWM signal is at a low level, the high-color-temperature LED circuit is driven to emit light. The ratio of the average current flowing through the high-color-temperature LED circuit to the average current flowing through the low-color-temperature LED circuit corresponds to the duty cycle of the PWM signal. By setting the duty cycle of the PWM signal, the color temperature of the mixed light is set.

[0004] Although the PWM signal has a relatively high precision in setting the color temperature of the mixed light, due to certain differences in the luminous efficiency of the high-color-temperature LED circuit and the low-color-temperature LED circuit, the method of driving the high-color-temperature LED circuit and the low-color-temperature LED circuit to emit light in a time-sharing manner will inevitably cause a stroboscopic phenomenon, affecting the lighting effect. Summary of the Invention

[0005] The technical problem to be solved by the present utility model is to provide a color temperature setting circuit for an LED lamp that has a high precision in setting the mixed light color temperature and does not produce a stroboscopic phenomenon.

[0006] The technical solution adopted by the present utility model to solve the above technical problem is as follows: A color temperature setting circuit for an LED lamp includes a high-color-temperature LED circuit capable of emitting high-color-temperature light and a low-color-temperature LED circuit capable of emitting low-color-temperature light. The color temperature setting circuit further includes a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistance setting circuit, and a voltage stabilizing circuit. The voltage stabilizing circuit is used to provide a working voltage for the first current control circuit, the second current control circuit, and the voltage sampling circuit. A voltage threshold is preset at the voltage sampling circuit. The voltage sampling circuit is used to generate corresponding voltages based on the comparison result between the smaller of the voltage signals provided by the first current control circuit and the second current control circuit and the voltage threshold, and output them to the first current control circuit and the second current control circuit respectively. The resistance setting circuit is used to set the required resistance values for the first current control circuit and the second current control circuit respectively. The first current control circuit is used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set for it by the resistance setting circuit to drive the high-color-temperature LED circuit to emit light. The second current control circuit is used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set for it by the resistance setting circuit to drive the low-color-temperature LED circuit to emit light.

[0007] Both the high-color-temperature LED circuit and the low-color-temperature LED circuit have a positive electrode and a negative electrode; both the first current control circuit and the second current control circuit have a positive electrode, a negative electrode, a current setting terminal, a current adjustment terminal, and a current output terminal. The voltage output by the current setting terminal thereof is proportional to the voltage applied to the current adjustment terminal thereof. By changing the resistance value between the current setting terminal and the negative electrode thereof, the magnitude of the current output by the current output terminal thereof can be set; the voltage sampling circuit has a positive electrode, a negative electrode, a first input terminal, a second input terminal, and an output terminal, and the smaller of the voltages applied to the first input terminal and the second input terminal thereof is used to compare with the voltage threshold. The larger this smaller value is, the larger the voltage output by the output terminal thereof; the smaller this smaller value is, the smaller the voltage output by the output terminal thereof; the resistance setting circuit has a first terminal, a second terminal, and a common terminal in total. The resistance setting circuit can set the resistance value between the first terminal and the common terminal and the resistance value between the second terminal and the common terminal. The resistance value between the first terminal and the common terminal is set for the first current control circuit, and the resistance value between the second terminal and the common terminal is set for the second current control circuit; the voltage stabilizing circuit has an input terminal, an output terminal, and a negative electrode. The voltage stabilizing circuit is used to convert the voltage applied to the input terminal thereof into the operating voltage required by the first current control circuit, the second current control circuit, and the voltage sampling circuit and output it at the output terminal; the input terminal of the voltage stabilizing circuit, the positive electrode of the high-color-temperature LED circuit, and the positive electrode of the low-color-temperature LED circuit are connected, and the connection terminal is the positive electrode of the color temperature setting circuit. The negative electrode of the high-color-temperature LED circuit, the current output terminal of the first current control circuit, and the first input terminal of the voltage sampling circuit are connected. The negative electrode of the low-color-temperature LED circuit, the current output terminal of the second current control circuit, and the second input terminal of the voltage sampling circuit are connected. The current adjustment terminals of the first current control circuit, the second current control circuit, and the output terminal of the voltage sampling circuit are connected. The current setting terminal of the first current control circuit and the first terminal of the resistance setting circuit are connected. The current setting terminal of the second current control circuit and the second terminal of the resistance setting circuit are connected. The common terminal of the resistance setting circuit, the negative electrode of the first current control circuit, the negative electrode of the second current control circuit, the negative electrode of the voltage sampling circuit, and the negative electrode of the voltage stabilizing circuit are connected, and the connection terminal is the negative electrode of the current setting circuit. The positive electrodes of the first current control circuit, the second current control circuit, the positive electrode of the voltage sampling circuit, and the output terminal of the voltage stabilizing circuit are connected.

[0008] The voltage sampling circuit described above includes a first resistor, a second resistor, a first capacitor, a first diode, a second diode, a third diode, and a fourth diode. The first diode, the second diode, the third diode, and the fourth diode are all rectifier diodes. One end of the first resistor is the positive electrode of the voltage sampling circuit. The other end of the first resistor, the positive electrodes of the first diode, the second diode, and the third diode are connected. The negative electrode of the first diode is the first input terminal of the voltage sampling circuit. The negative electrode of the second diode is the second input terminal of the voltage sampling circuit. The negative electrode of the third diode is connected to the positive electrode of the fourth diode. The negative electrode of the fourth diode, one end of the second resistor, and one end of the first capacitor are connected, and the connection terminal is the output terminal of the voltage sampling circuit. The other end of the second resistor and the other end of the first capacitor are connected, and the connection terminal is the negative electrode of the voltage sampling circuit.

[0009] The resistor setting circuit described above includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a five-position toggle switch. The five-position toggle switch has a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, and a common terminal. Its common terminal can be individually connected to any one of its first terminal, second terminal, third terminal, fourth terminal, and fifth terminal. One end of the third resistor, one end of the fourth resistor, and the first terminal of the five-position toggle switch are connected, and the connection terminal is the first end of the resistor setting circuit. One end of the fifth resistor, one end of the sixth resistor, and the fifth terminal of the five-position toggle switch are connected, and the connection terminal is the second end of the resistor setting circuit. The other end of the third resistor is connected to the second terminal of the five-position toggle switch. The other end of the sixth resistor is connected to the fourth terminal of the five-position toggle switch. The other end of the fourth resistor, the other end of the fifth resistor, and the common terminal of the five-position toggle switch are connected, and the connection terminal is the common end of the resistor setting circuit.

[0010] The described first current control circuit includes a first MOS transistor and a first operational amplifier circuit. The first operational amplifier circuit has a positive terminal, a negative terminal, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the first MOS transistor is the current output terminal of the first current control circuit. The gate of the first MOS transistor is connected to the output terminal of the first operational amplifier circuit. The source of the first MOS transistor is connected to the inverting input terminal of the first operational amplifier circuit, and the connection end is the current setting terminal of the first current control circuit. The non-inverting input terminal of the first operational amplifier circuit is the current adjustment terminal of the first current control circuit. The positive terminal of the first operational amplifier circuit is the positive terminal of the first current control circuit. The negative terminal of the first operational amplifier circuit is the negative terminal of the first current control circuit.

[0011] The described second current control circuit includes a second MOS transistor and a second operational amplifier circuit. The second operational amplifier circuit has a positive terminal, a negative terminal, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the second MOS transistor is the current output terminal of the second current control circuit. The gate of the second MOS transistor is connected to the output terminal of the second operational amplifier circuit. The source of the second MOS transistor is connected to the inverting input terminal of the second operational amplifier circuit, and the connection end is the current setting terminal of the second current control circuit. The non-inverting input terminal of the second operational amplifier circuit is the current adjustment terminal of the second current control circuit. The positive terminal of the second operational amplifier circuit is the positive terminal of the second current control circuit. The negative terminal of the second operational amplifier circuit is the negative terminal of the second current control circuit.

[0012] The described voltage stabilizing circuit includes a seventh resistor, a fifth diode, and a second capacitor. The fifth diode is a zener diode. One end of the seventh resistor is the input terminal of the voltage stabilizing circuit. The other end of the seventh resistor, the negative terminal of the fifth diode, and one end of the second capacitor are connected, and the connection end is the output terminal of the voltage stabilizing circuit. The positive terminal of the fifth diode and the other end of the second capacitor are connected, and the connection end is the negative terminal of the voltage stabilizing circuit.

[0013] Compared with the prior art, the utility model has the advantages that by setting a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistance setting circuit and a voltage stabilizing circuit, the voltage stabilizing circuit provides an operating voltage for the first current control circuit, the second current control circuit and the voltage sampling circuit, the current generated by the first current control circuit drives the high color temperature LED circuit to emit high color temperature light, the current generated by the second current control circuit drives the low color temperature LED circuit to emit low color temperature light, the voltage sampling circuit outputs the same voltage to the first current control circuit and the second current control circuit, the ratio of the currents generated by the first current control circuit and the second current control circuit corresponds to the ratio of the resistance values set by the resistance setting circuit for the first current control circuit and the second current control circuit, and by changing the resistance setting circuit for the first current control circuit and the second current control circuit The ratio of the resistance values set by the current control circuit can adjust the ratio of the currents connected to the high color temperature LED circuit and the low color temperature LED circuit, thereby adjusting the ratio of the luminous intensity of the high color temperature LED circuit and the low color temperature LED circuit, and realizing the color temperature adjustment of the mixed light formed by the high color temperature LED circuit and the low color temperature LED circuit. Since the voltage sampling circuit outputs a stable voltage, the currents flowing through the high color temperature LED circuit and the low color temperature LED circuit are both stable values, which not only enables the mixed light color temperature to have a higher setting accuracy, but also does not generate flicker caused by the difference in luminous efficiency of the high color temperature LED circuit and the low color temperature LED circuit when the high color temperature LED circuit and the low color temperature LED circuit are driven by PWM signals in a time-sharing manner. Therefore, the utility model has a higher mixed light color temperature setting accuracy and does not generate flicker. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural principle block diagram of the color temperature setting circuit of the LED lamp of the utility model;

[0015] Figure 2 The present invention is a circuit diagram of a color temperature setting circuit for an LED lamp. DETAILED DESCRIPTION

[0016] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0017] Embodiment 1: A color temperature setting circuit for an LED lamp, comprising a high color temperature LED circuit capable of emitting high color temperature light and a low color temperature LED circuit capable of emitting low color temperature light, the color temperature setting circuit further comprising a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistance setting circuit and a voltage stabilizing circuit, the voltage stabilizing circuit being used to provide an operating voltage for the first current control circuit, the second current control circuit and the voltage sampling circuit, a voltage threshold being preset at the voltage sampling circuit, the voltage sampling circuit being used to generate a corresponding voltage based on a comparison result between the smaller of the voltage signals provided by the first current control circuit and the second current control circuit and the voltage threshold and output the voltage to the first current control circuit and the second current control circuit respectively, the resistance setting circuit being used to set a required resistance value for the first current control circuit and the second current control circuit respectively, the first current control circuit being used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set by the resistance setting circuit to drive the high color temperature LED circuit to emit light, and the second current control circuit being used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set by the resistance setting circuit to drive the low color temperature LED circuit to emit light.

[0018] In this embodiment, by setting a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistance setting circuit and a voltage stabilizing circuit, the voltage stabilizing circuit provides an operating voltage for the first current control circuit, the second current control circuit and the voltage sampling circuit, the current generated by the first current control circuit drives the high color temperature LED circuit to emit high color temperature light, the current generated by the second current control circuit drives the low color temperature LED circuit to emit low color temperature light, the voltage sampling circuit outputs the same voltage to the first current control circuit and the second current control circuit, the ratio of the current generated by the first current control circuit and the second current control circuit corresponds to the ratio of the resistance values set by the resistance setting circuit for the first current control circuit and the second current control circuit, and by changing the resistance setting circuit The ratio of the resistance values set for the first current control circuit and the second current control circuit can adjust the ratio of the currents connected to the high color temperature LED circuit and the low color temperature LED circuit, thereby adjusting the ratio of the luminous intensity of the high color temperature LED circuit and the low color temperature LED circuit, and realizing the color temperature adjustment of the mixed light formed by the high color temperature LED circuit and the low color temperature LED circuit. Since the voltage sampling circuit outputs a stable voltage, the currents flowing through the high color temperature LED circuit and the low color temperature LED circuit are both stable values, which not only enables the color temperature of the mixed light to have a higher setting accuracy, but also avoids the flicker caused by the difference in luminous efficiency of the high color temperature LED circuit and the low color temperature LED circuit when the high color temperature LED circuit and the low color temperature LED circuit are driven in time-sharing mode using a PWM signal.

[0019] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that: in this embodiment, Figure 1As shown, both the high-color-temperature LED circuit and the low-color-temperature LED circuit have a positive electrode and a negative electrode; both the first current control circuit and the second current control circuit have a positive electrode, a negative electrode, a current setting terminal, a current adjustment terminal, and a current output terminal. The voltage output by the current setting terminal is proportional to the voltage applied to the current adjustment terminal. By changing the resistance value between the current setting terminal and the negative electrode, the magnitude of the current output by the current output terminal can be set; the voltage sampling circuit has a positive electrode, a negative electrode, a first input terminal, a second input terminal, and an output terminal. The smaller of the voltages applied to the first input terminal and the second input terminal is used to compare with a voltage threshold. The larger this smaller value is, the larger the voltage output by the output terminal; the smaller this smaller value is, the smaller the voltage output by the output terminal; the resistance setting circuit has a first terminal, a second terminal, and a common terminal. The resistance setting circuit can set the resistance value between the first terminal and the common terminal and the resistance value between the second terminal and the common terminal. The resistance value between the first terminal and the common terminal is set for the first current control circuit, and the resistance value between the second terminal and the common terminal is set for the second current control circuit; the voltage stabilizing circuit has an input terminal, an output terminal, and a negative electrode. The voltage stabilizing circuit is used to convert the voltage applied to its input terminal into the operating voltage required by the first current control circuit, the second current control circuit, and the voltage sampling circuit and output it at its output terminal; the input terminal of the voltage stabilizing circuit, the positive electrode of the high-color-temperature LED circuit, and the positive electrode of the low-color-temperature LED circuit are connected, and the connection end is the positive electrode of the color temperature setting circuit. The negative electrode of the high-color-temperature LED circuit, the current output terminal of the first current control circuit, and the first input terminal of the voltage sampling circuit are connected. The negative electrode of the low-color-temperature LED circuit, the current output terminal of the second current control circuit, and the second input terminal of the voltage sampling circuit are connected. The current adjustment terminals of the first current control circuit, the second current control circuit, and the output terminal of the voltage sampling circuit are connected. The current setting terminal of the first current control circuit is connected to the first terminal of the resistance setting circuit. The current setting terminal of the second current control circuit is connected to the second terminal of the resistance setting circuit. The common terminal of the resistance setting circuit, the negative electrode of the first current control circuit, the negative electrode of the second current control circuit, the negative electrode of the voltage sampling circuit, and the negative electrode of the voltage stabilizing circuit are connected, and the connection end is the negative electrode of the current setting circuit. The positive electrodes of the first current control circuit, the second current control circuit, the positive electrode of the voltage sampling circuit, and the output terminal of the voltage stabilizing circuit are connected.

[0020] In this embodiment, when a current is applied between the positive and negative electrodes of the high-color-temperature LED circuit, the high-color-temperature LED circuit emits high-color-temperature light, and its luminous intensity is proportional to the magnitude of the current applied between its positive and negative electrodes; when a current is applied between the positive and negative electrodes of the low-color-temperature LED circuit, the low-color-temperature LED circuit emits low-color-temperature light, and its luminous intensity is proportional to the magnitude of the current applied between its positive and negative electrodes; when the high-color-temperature LED circuit and the low-color-temperature LED circuit emit light simultaneously, the color-temperature setting circuit emits a mixed light formed by the high-color-temperature light and the low-color-temperature light, and the color temperature of the mixed light corresponds to the ratio of the luminous intensity of the high-color-temperature light to the luminous intensity of the low-color-temperature light; the ratio of the luminous intensity of the high-color-temperature light to the luminous intensity of the low-color-temperature light corresponds to the ratio of the currents applied to the high-color-temperature LED circuit and the low-color-temperature LED circuit. By setting the ratio of the currents applied to the high-color-temperature LED circuit and the low-color-temperature LED circuit, the luminous intensity of the mixed light, i.e., the luminous color temperature, can be set; when a DC current is applied between the positive and negative electrodes of the color-temperature setting circuit, a DC voltage is generated between its positive and negative electrodes. At this time, a part of the DC current applied between the positive and negative electrodes of the color-temperature setting circuit flows into the input terminal of the voltage stabilizing circuit, and a DC voltage is generated between its output terminal and the negative electrode to provide a working voltage for the voltage sampling circuit, the first current setting circuit, and the second current setting circuit. The voltage magnitudes at the current setting terminals of the first current control circuit and the current setting terminals of the second circuit control ground circuit are the same. The voltage sampling circuit outputs a voltage to the current adjustment terminals of the first current control circuit and the current adjustment terminals of the second circuit control ground circuit, such that the sum of the current flowing through the input terminal of the voltage stabilizing circuit, the current output from the current output terminal of the first current control circuit, and the current output from the current output terminal of the second current control circuit is equal to the magnitude of the DC current applied between the positive and negative electrodes of the color-temperature setting circuit. If the voltage at the current setting terminal of the first current control circuit is denoted as Vcs, the current output from its current output terminal is denoted as Io, and the resistance value of the resistor connecting its current setting terminal and the negative electrode is denoted as R, then the relationship between them is: Io = Vcs / R. Similarly, the current output from the current output terminal of the second current control circuit is also equal to the value obtained by dividing the voltage at its current setting terminal by the resistance value of the resistor connecting its current setting terminal and the negative electrode; assuming that the resistance value between the first terminal and the common terminal in the resistor setting circuit is R1, the resistance value between the second terminal and the common terminal is R2, the current flowing through the current output terminal of the first current control circuit is I1, and the current flowing through the current output terminal of the second current control circuit is I2, then R1 / R2 = I2 / I1. The resistor setting circuit can set the ratio of the magnitudes of the currents flowing through the high-color-temperature LED circuit and the low-color-temperature LED circuit by setting the ratio of the resistance value between its first terminal and the common terminal to the resistance value between its second terminal and the common terminal, thereby setting the mixed light color temperature.

[0021] Embodiment 3: This embodiment is basically the same as Embodiment 2, except that: in this embodiment, as Figure 2As shown in the figure, the voltage sampling circuit includes a first resistor R1, a second resistor R2, a first capacitor C1, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 are all rectifier diodes. One end of the first resistor R1 is the positive pole of the voltage sampling circuit. The other end of the first resistor R1, the positive poles of the first diode D1, the second diode D2, and the third diode D3 are connected. The negative pole of the first diode D1 is the first input terminal of the voltage sampling circuit. The negative pole of the second diode D2 is the second input terminal of the voltage sampling circuit. The negative pole of the third diode D3 and the positive pole of the fourth diode D4 are connected. The negative pole of the fourth diode D4, one end of the second resistor R2, and one end of the first capacitor C1 are connected, and their connection terminal is the output terminal of the voltage sampling circuit. The other end of the second resistor R2 and the other end of the first capacitor C1 are connected, and their connection terminal is the negative pole of the voltage sampling circuit.

[0022] In the voltage sampling circuit of this embodiment, the voltage threshold is the forward conduction voltage value of a rectifier diode. The voltage output at the output terminal of the voltage sampling circuit is obtained by subtracting the conduction voltage value of a rectifier diode from the lower voltage value of the voltages input at the first input terminal and the second input terminal of the voltage sampling circuit.

[0023] Embodiment 4: This embodiment is basically the same as Embodiment 2, except that: in this embodiment, as Figure 2 shown, the resistor setting circuit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a five-position toggle switch SW. The five-position toggle switch SW has a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, and a common terminal. Its common terminal can be individually connected to any one of its first terminal, second terminal, third terminal, fourth terminal, and fifth terminal. One end of the third resistor R3, one end of the fourth resistor R4, and the first terminal of the five-position toggle switch SW are connected, and their connection terminal is the first end of the resistor setting circuit. One end of the fifth resistor R5, one end of the sixth resistor R6, and the fifth terminal of the five-position toggle switch SW are connected, and their connection terminal is the second end of the resistor setting circuit. The other end of the third resistor R3 is connected to the second terminal of the five-position toggle switch SW. The other end of the sixth resistor R6 is connected to the fourth terminal of the five-position toggle switch SW. The other end of the fourth resistor R4, the other end of the fifth resistor R5, and the common terminal of the five-position toggle switch SW are connected, and their connection terminal is the common end of the resistor setting circuit.

[0024] Embodiment 5: This embodiment is basically the same as Embodiment 2, except that: in this embodiment, as Figure 2As shown, the first current control circuit includes a first MOS transistor Q1 and a first operational amplifier circuit U1. The first operational amplifier circuit U1 has a positive terminal, a negative terminal, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the first MOS transistor Q1 is the current output terminal of the first current control circuit. The gate of the first MOS transistor Q1 is connected to the output terminal of the first operational amplifier circuit U1. The source of the first MOS transistor Q1 is connected to the inverting input terminal of the first operational amplifier circuit U1, and the connection terminal is the current setting terminal of the first current control circuit. The non-inverting input terminal of the first operational amplifier circuit U1 is the current adjustment terminal of the first current control circuit. The positive terminal of the first operational amplifier circuit U1 is the positive terminal of the first current control circuit. The negative terminal of the first operational amplifier circuit U1 is the negative terminal of the first current control circuit.

[0025] Embodiment Six: This embodiment is basically the same as Embodiment Two, except that: in this embodiment, as Figure 2 shown, the second current control circuit includes a second MOS transistor Q2 and a second operational amplifier circuit U2. The second operational amplifier circuit U2 has a positive terminal, a negative terminal, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the second MOS transistor Q2 is the current output terminal of the second current control circuit. The gate of the second MOS transistor Q2 is connected to the output terminal of the second operational amplifier circuit U2. The source of the second MOS transistor Q2 is connected to the inverting input terminal of the second operational amplifier circuit U2, and the connection terminal is the current setting terminal of the second current control circuit. The non-inverting input terminal of the second operational amplifier circuit U2 is the current adjustment terminal of the second current control circuit. The positive terminal of the second operational amplifier circuit U2 is the positive terminal of the second current control circuit. The negative terminal of the second operational amplifier circuit U2 is the negative terminal of the second current control circuit.

[0026] Embodiment Seven: This embodiment is basically the same as Embodiment Two, except that: in this embodiment, as Figure 2 shown, the voltage stabilizing circuit includes a seventh resistor R7, a fifth diode D5, and a second capacitor C2. The fifth diode D5 is a voltage stabilizing diode. One end of the seventh resistor R7 is the input terminal of the voltage stabilizing circuit. The other end of the seventh resistor R7, the negative terminal of the fifth diode D5, and one end of the second capacitor C2 are connected, and the connection terminal is the output terminal of the voltage stabilizing circuit. The positive terminal of the fifth diode D5 and the other end of the second capacitor C2 are connected, and the connection terminal is the negative terminal of the voltage stabilizing circuit.

Claims

1. A color temperature setting circuit for an LED lamp, comprising a high color temperature LED circuit capable of emitting high color temperature light and a low color temperature LED circuit capable of emitting low color temperature light, characterized in that The described color temperature setting circuit further includes a first current control circuit, a second current control circuit, a voltage sampling circuit, a resistor setting circuit, and a voltage stabilizing circuit. The voltage stabilizing circuit is used to provide operating voltages for the first current control circuit, the second current control circuit, and the voltage sampling circuit. A voltage threshold is preset at the voltage sampling circuit. The voltage sampling circuit is used to generate corresponding voltages based on the comparison result between the smaller of the voltage signals provided by the first current control circuit and the second current control circuit and the voltage threshold, and output them to the first current control circuit and the second current control circuit respectively. The resistor setting circuit is used to set the required resistance values for the first current control circuit and the second current control circuit respectively. The first current control circuit is used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set for it by the resistor setting circuit to drive the high color temperature LED circuit to emit light. The second current control circuit is used to generate a corresponding current according to the voltage output by the voltage sampling circuit and the resistance value set for it by the resistor setting circuit to drive the low color temperature LED circuit to emit light.

2. The color temperature setting circuit of an LED lamp according to claim 1, characterized in that Both the high-color-temperature LED circuit and the low-color-temperature LED circuit have a positive electrode and a negative electrode; both the first current control circuit and the second current control circuit have a positive electrode, a negative electrode, a current setting terminal, a current adjusting terminal, and a current output terminal. The voltage output by the current setting terminal is proportional to the voltage applied to the current adjusting terminal. By changing the resistance value between the current setting terminal and the negative electrode, the magnitude of the current output by the current output terminal can be set; the voltage sampling circuit has a positive electrode, a negative electrode, a first input terminal, a second input terminal, and an output terminal. The smaller of the voltages applied to the first input terminal and the second input terminal is used to compare with the voltage threshold. The larger the smaller value is, the larger the voltage output by the output terminal is, and the smaller the smaller value is, the smaller the voltage output by the output terminal is; the resistance setting circuit has a first terminal, a second terminal, and a common terminal. The resistance setting circuit can set the resistance value between the first terminal and the common terminal and the resistance value between the second terminal and the common terminal. The resistance value between the first terminal and the common terminal is set for the first current control circuit, and the resistance value between the second terminal and the common terminal is set for the second current control circuit; the voltage stabilizing circuit has an input terminal, an output terminal, and a negative electrode. The voltage stabilizing circuit is used to convert the voltage applied to its input terminal into the operating voltage required by the first current control circuit, the second current control circuit, and the voltage sampling circuit and output it at its output terminal; the input terminal of the voltage stabilizing circuit, the positive electrode of the high-color-temperature LED circuit, and the positive electrode of the low-color-temperature LED circuit are connected, and the connection end is the positive electrode of the color temperature setting circuit. The negative electrode of the high-color-temperature LED circuit, the current output terminal of the first current control circuit, and the first input terminal of the voltage sampling circuit are connected. The negative electrode of the low-color-temperature LED circuit, the current output terminal of the second current control circuit, and the second input terminal of the voltage sampling circuit are connected. The current adjusting terminals of the first current control circuit, the second current control circuit, and the output terminal of the voltage sampling circuit are connected. The current setting terminal of the first current control circuit is connected to the first terminal of the resistance setting circuit. The current setting terminal of the second current control circuit is connected to the second terminal of the resistance setting circuit. The common terminal of the resistance setting circuit, the negative electrode of the first current control circuit, the negative electrode of the second current control circuit, the negative electrode of the voltage sampling circuit, and the negative electrode of the voltage stabilizing circuit are connected, and the connection end is the negative electrode of the current setting circuit. The positive electrodes of the first current control circuit, the second current control circuit, the positive electrode of the voltage sampling circuit, and the output terminal of the voltage stabilizing circuit are connected.

3. The color temperature setting circuit of an LED lamp according to claim 2, wherein The voltage sampling circuit described above includes a first resistor, a second resistor, a first capacitor, a first diode, a second diode, a third diode, and a fourth diode. The first diode, the second diode, the third diode, and the fourth diode are all rectifier diodes. One end of the first resistor is the positive electrode of the voltage sampling circuit. The other end of the first resistor, the positive electrodes of the first diode, the second diode, and the third diode are connected. The negative electrode of the first diode is the first input terminal of the voltage sampling circuit. The negative electrode of the second diode is the second input terminal of the voltage sampling circuit. The negative electrode of the third diode is connected to the positive electrode of the fourth diode. The negative electrode of the fourth diode, one end of the second resistor, and one end of the first capacitor are connected, and their connection end is the output terminal of the voltage sampling circuit. The other end of the second resistor and the other end of the first capacitor are connected, and their connection end is the negative electrode of the voltage sampling circuit.

4. The color temperature setting circuit of an LED lamp according to claim 2, wherein The resistor setting circuit described above includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a five-position toggle switch. The five-position toggle switch has a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, and a common terminal. Its common terminal can be individually connected to any one of its first terminal, second terminal, third terminal, fourth terminal, and fifth terminal. One end of the third resistor, one end of the fourth resistor, and the first terminal of the five-position toggle switch are connected, and their connection end is the first end of the resistor setting circuit. One end of the fifth resistor, one end of the sixth resistor, and the fifth terminal of the five-position toggle switch are connected, and their connection end is the second end of the resistor setting circuit. The other end of the third resistor is connected to the second terminal of the five-position toggle switch. The other end of the sixth resistor is connected to the fourth terminal of the five-position toggle switch. The other end of the fourth resistor, the other end of the fifth resistor, and the common terminal of the five-position toggle switch are connected, and their connection end is the common end of the resistor setting circuit.

5. The color temperature setting circuit of an LED lamp according to claim 2, characterized in that The first current control circuit described above includes a first MOS transistor and a first operational amplifier circuit. The first operational amplifier circuit has a positive electrode, a negative electrode, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the first MOS transistor is the current output terminal of the first current control circuit. The gate of the first MOS transistor is connected to the output terminal of the first operational amplifier circuit. The source of the first MOS transistor is connected to the inverting input terminal of the first operational amplifier circuit, and their connection end is the current setting terminal of the first current control circuit. The non-inverting input terminal of the first operational amplifier circuit is the current adjustment terminal of the first current control circuit. The positive electrode of the first operational amplifier circuit is the positive electrode of the first current control circuit. The negative electrode of the first operational amplifier circuit is the negative electrode of the first current control circuit.

6. The color temperature setting circuit of an LED lamp according to claim 2, characterized in that The second current control circuit includes a second MOS transistor and a second operational amplifier circuit. The second operational amplifier circuit has a positive electrode, a negative electrode, a non-inverting input terminal, an inverting input terminal, and an output terminal. The drain of the second MOS transistor is the current output terminal of the second current control circuit. The gate of the second MOS transistor is connected to the output terminal of the second operational amplifier circuit. The source of the second MOS transistor is connected to the inverting input terminal of the second operational amplifier circuit, and the connection terminal is the current setting terminal of the second current control circuit. The non-inverting input terminal of the second operational amplifier circuit is the current adjustment terminal of the second current control circuit. The positive electrode of the second operational amplifier circuit is the positive electrode of the second current control circuit. The negative electrode of the second operational amplifier circuit is the negative electrode of the second current control circuit.

7. The color temperature setting circuit of an LED lamp according to claim 2, wherein The voltage stabilizing circuit includes a seventh resistor, a fifth diode, and a second capacitor. The fifth diode is a voltage stabilizing diode. One end of the seventh resistor is the input terminal of the voltage stabilizing circuit. The other end of the seventh resistor, the negative electrode of the fifth diode, and one end of the second capacitor are connected, and the connection terminal is the output terminal of the voltage stabilizing circuit. The positive electrode of the fifth diode and the other end of the second capacitor are connected, and the connection terminal is the negative electrode of the voltage stabilizing circuit.

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