Voltage control circuit of lamp liquid crystal lens and dyeing lamp

Abstract

The utility model provides a kind of voltage control circuit and dyeing lamp of stage light liquid crystal lens, it is related to driving circuit technical field, comprising: DAC voltage regulating circuit, for the first PWM signal of MCU output is handled, to adjust the voltage amplitude of the liquid crystal of driving the stage light liquid crystal lens, output first drive signal;MOS drive circuit, for the second PWM signal of MCU output is according to, generate two second drive signals of opposite phase;Drive signal amplification circuit, for the first drive signal and the second drive signal generate alternating current drive signal of driving liquid crystal according to.The utility model can realize the liquid crystal drive of output drive voltage adjustable by less PWM signal, by adjusting the amplitude of drive output, different atomization or amplification effect of liquid crystal lens can be realized, with light fixture weight reduction, reduce light fixture size, reduce heat, facilitate installation maintenance and the like advantages.

Description

Technical Field

[0001] This utility model relates to the field of driving circuit technology, and in particular to a voltage control circuit for a lamp liquid crystal lens and a color-changing lamp. Background Technology

[0002] Currently, stage lights typically use motors and mechanical structures to move the lens to achieve magnification or fogging effects. This method is complex, and the motors and mechanical structures increase the weight and size of the lamp, leading to problems such as motor overheating and difficulty in disassembly and assembly.

[0003] Currently, there are methods to achieve light atomization or zoom functions using liquid crystal lenses. These methods utilize the deformation of the liquid crystal under different voltage amplitudes to achieve varying transmittance and beam angles, thus creating atomization or zoom effects. However, when multiple liquid crystal lenses need to be driven simultaneously, multiple PWM signals are typically required for separate control, necessitating a MCU with numerous pins, which increases cost. Summary of the Invention

[0004] This invention provides a voltage control circuit for a liquid crystal lens in a lamp and a color-changing lamp, which solves the defect in the prior art that liquid crystals will age and gradually lose their deformation ability when subjected to a constant DC voltage for a long time, and realizes the deformation of liquid crystals driven by AC power.

[0005] This utility model provides a voltage control circuit for a lamp's liquid crystal lens, comprising:

[0006] A DAC voltage regulation circuit is provided, the input of which is connected to the MCU of the stage lighting liquid crystal lens. The DAC voltage regulation circuit is used to process the first PWM signal output by the MCU to adjust the voltage amplitude of the liquid crystal driving the stage lighting liquid crystal lens and output the first driving signal.

[0007] A MOS driving circuit, the input terminal of which is connected to the MCU, is used to generate two second driving signals with opposite phases according to the second PWM signal output by the MCU;

[0008] Two drive signal amplification circuits are provided. The input terminal of each drive signal amplification circuit is connected to the output terminal of the DAC voltage regulation circuit and the output terminal of the MOS drive circuit. The two drive signal amplification circuits receive two second drive signals with opposite phases. The output terminal of each drive signal amplification circuit is connected to the stage lighting liquid crystal lens. Each drive signal amplification circuit is used to generate an AC drive signal to drive the liquid crystal based on the first drive signal and the second drive signal it receives.

[0009] According to the present invention, a voltage control circuit for a lamp liquid crystal lens is provided, wherein the DAC voltage regulation circuit includes a voltage follower circuit and an RC filter circuit.

[0010] The input terminal of the RC filter circuit is connected to the MCU to receive the first PWM signal output by the MCU. The output terminal of the RC filter circuit is connected to the positive input terminal of the first operational amplifier. The output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier to form the voltage follower circuit.

[0011] According to the present invention, a voltage control circuit for a lamp liquid crystal lens is provided, wherein the MOS driving circuit includes a MOS driving IC;

[0012] The positive and negative input terminals of the MOS driver IC are connected to the MCU to receive the second PWM signal output by the MCU. The output terminal of the MOS driver IC outputs two second drive signals with opposite phases.

[0013] According to the present invention, a voltage control circuit for a lamp liquid crystal lens is provided, wherein each drive signal amplification circuit includes an NMOS transistor, a pull-down resistor, and a second operational amplifier.

[0014] The drain of the NMOS transistor is connected to the output terminal of the DAC voltage regulation circuit to receive the first drive signal output by the DAC voltage regulation circuit.

[0015] The gate of the NMOS transistor is connected to the output terminal of the MOS driving circuit, and the transistor switches to receive one of the two second driving signals with opposite phases output by the MOS driving circuit.

[0016] The source (S) terminal of the NMOS transistor is connected to the positive input terminal of the second operational amplifier and grounded through the pull-down resistor. The output terminal of the second operational amplifier outputs an AC drive signal to drive the liquid crystal.

[0017] According to the voltage control circuit of the liquid crystal lens of the lamp provided by this utility model, each driving signal amplification circuit further includes a push-pull circuit. The push-pull circuit includes an NPN transistor and a PNP transistor. The base of the NPN transistor and the base of the PNP transistor are connected to the output terminal of the second operational amplifier. The emitter of the PNP transistor and the emitter of the NPN transistor are combined to output an AC driving signal for driving the liquid crystal. The collector of the PNP transistor and the collector of the NPN transistor are grounded.

[0018] According to the voltage control circuit of the liquid crystal lens of the lamp provided by the present invention, each drive signal amplification circuit further includes a feedback circuit, and the feedback circuit includes a first resistor and a second resistor.

[0019] One end of the first resistor is connected to the output terminal of the second operational amplifier, and the other end is connected to the inverting input terminal of the second operational amplifier;

[0020] One end of the second resistor is grounded, and the other end is connected to the inverting input of the second operational amplifier.

[0021] According to the voltage control circuit of the liquid crystal lens of the lamp provided by this utility model, when the second driving signal is high, the voltage of the NMOS transistor is greater than or equal to the MOS transistor turn-on voltage of the NMOS transistor, the NMOS transistor is turned on, the voltage of the positive input terminal of the second operational amplifier is the voltage of the first driving signal, and the output voltage of the driving signal amplification circuit is not 0.

[0022] When the second drive signal is low, the voltage of the NMOS transistor is less than the turn-on voltage of the MOS transistor, the NMOS transistor is turned off, the voltage at the positive input terminal of the second operational amplifier is pulled low by the pull-down resistor, and the voltage at the output terminal of the second operational amplifier is 0V.

[0023] According to the voltage control circuit of the liquid crystal lens of the lamp provided by this utility model, when the second driving signal is high, the output voltage of the driving signal amplification circuit is...

[0024] V OUT for:

[0025]

[0026] Among them, V IN R5 is the voltage at the positive input terminal of the second operational amplifier, which is equal to the voltage of the first drive signal. R4 is the resistance value of the second resistor.

[0027] According to the present invention, a voltage control circuit for a lamp liquid crystal lens is provided, wherein the maximum amplitude of the second driving signal is the power supply voltage, and the power supply voltage is greater than the sum of the MOS transistor turn-on voltage of the NMOS transistor and the maximum voltage of the first driving signal.

[0028] This utility model provides a color-changing lamp, comprising:

[0029] The lamp head is provided with multiple light sources, each light source corresponding to a liquid crystal lens, and each liquid crystal lens is controlled by the voltage control circuit of the liquid crystal lens of any of the above-mentioned lamps.

[0030] An arm for supporting the rotation of the lamp head;

[0031] The chassis is used to support the rotation of the arm.

[0032] The voltage control circuit for the liquid crystal lens of the lamp provided by this utility model and the color-changing lamp can realize the liquid crystal driving with adjustable output driving voltage through a small number of PWM signals. By adjusting the amplitude of the driving output, different fogging or magnification effects of the liquid crystal lens can be achieved. It can replace the fogging sheet or magnifying lens of existing stage lights, and achieve benefits such as reducing the weight and size of the lamp, reducing heat generation, and facilitating installation and maintenance. Since fewer control signals are required, when used in the color-changing lamp of stage lights, a MCU with fewer pins can be used to generate multiple liquid crystal driving signals. Each lamp can use a liquid crystal lens to achieve individual control of different fogging or magnification effects for each lamp, producing more optical effects. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the DAC voltage regulation circuit in the voltage control circuit of the liquid crystal lens for the lamp provided by this utility model;

[0035] Figure 2 This is a schematic diagram of the MOS driving circuit in the voltage control circuit of the liquid crystal lens for the lamp provided by this utility model;

[0036] Figure 3 This is a schematic diagram of the drive signal amplification circuit in the voltage control circuit of the liquid crystal lens for the lamp provided by this utility model;

[0037] Figure 4 This is a schematic diagram of the structure of the color-changing lamp provided by this utility model. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0039] The following is combined with Figures 1 to 3 This invention describes a voltage control circuit for a liquid crystal lens in a lamp, comprising:

[0040] A DAC (Digital-to-Analog Converter) voltage regulation circuit is provided. The input terminal of the DAC voltage regulation circuit is connected to the MCU (Microcontroller Unit) of the stage lighting liquid crystal lens. The DAC voltage regulation circuit is used to process the first PWM signal output by the MCU to adjust the voltage amplitude driving the liquid crystal of the stage lighting liquid crystal lens and output the first drive signal.

[0041] A MOS (Metal Oxide Semiconductor Field Effect Transistor) driving circuit is provided. The input terminal of the MOS driving circuit is connected to the MCU. The MOS driving circuit is used to generate two second driving signals with opposite phases according to the second PWM signal output by the MCU.

[0042] Two drive signal amplification circuits are provided. The input terminal of each drive signal amplification circuit is connected to the output terminal of the DAC voltage regulation circuit and the output terminal of the MOS drive circuit. The two drive signal amplification circuits receive two second drive signals with opposite phases. The output terminal of each drive signal amplification circuit is connected to the stage lighting liquid crystal lens. Each drive signal amplification circuit is used to generate an AC drive signal to drive the liquid crystal based on the first drive signal and the second drive signal it receives.

[0043] The voltage control circuit of the lamp's liquid crystal lens consists of three parts: a DAC voltage regulation circuit, a MOS driving circuit, and a driving signal amplification circuit. The DAC voltage regulation circuit is used to adjust the amplitude of the liquid crystal driving output voltage, the MOS driving circuit is used to generate two MOS driving signals with opposite phases, and the driving signal amplification circuit generates the driving signal to drive the liquid crystal.

[0044] A single drive circuit can output a square wave with an adjustable voltage from 0 to VDD. Through two complementary PWM signals, a square wave signal with a differential voltage from -VDD to VDD can be output.

[0045] This embodiment achieves adjustable output drive voltage for liquid crystal driving with fewer PWM signals. By adjusting the amplitude of the drive output, different atomization or magnification effects of the liquid crystal lens can be achieved. It can replace the atomizing sheet and magnifying lens of existing stage lights, achieving benefits such as light reduction, smaller light fixture size, reduced heat generation, and easier installation and maintenance.

[0046] Based on the above embodiments, such as Figure 1 As shown, the DAC voltage regulation circuit in this embodiment includes a voltage follower circuit and an RC filter circuit;

[0047] The input terminal of the RC filter circuit is connected to the MCU to receive the first PWM signal output by the MCU. The output terminal of the RC filter circuit is connected to the positive input terminal of the first operational amplifier. The output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier to form the voltage follower circuit.

[0048] like Figure 1 As shown, the first PWM signal DAC_PWM, the input signal of the DAC voltage regulation circuit, is a PWM square wave with a duty cycle of 0-100% output from the MCU. After being filtered by an RC filter circuit, DAC_PWM is connected to the positive input terminal of the first operational amplifier U2. The output terminal of the first operational amplifier U2 is connected in parallel to the inverting input terminal, forming a voltage follower circuit. The voltage follower circuit is used to enhance the DC drive capability after RC filtering.

[0049] The DAC circuit receives a high-frequency PWM signal with a duty cycle of 0-100% from the MCU. After passing through an RC low-pass filter circuit (which can be a first-order or multi-order filter), it is converted into a DC voltage of 0-3.3V. The higher the duty cycle of the PWM wave, the higher the voltage amplitude after filtering. The output of the RC filter circuit passes through a voltage follower circuit composed of operational amplifiers, and the output is still a 0-3.3V signal, but the signal driving capability is enhanced.

[0050] Based on the above embodiments, such as Figure 2 As shown, the MOS driving circuit in this embodiment includes a MOS driving IC (Integrated Circuit).

[0051] The positive and negative input terminals of the MOS driver IC are connected to the MCU to receive the second PWM signal output by the MCU. The output terminal of the MOS driver IC outputs two second drive signals with opposite phases.

[0052] The MOS drive circuit uses a MOS driver IC with positive and negative inputs. The PWM_A signal output by the MCU is connected to the positive input terminal and the negative input terminal of the MOS driver IC respectively. The OUT terminal of the MOS driver IC can output two second drive signals, PWM_A+ and PWM_A-, with opposite phases and amplitudes of VCC.

[0053] Based on the above embodiments, such as Figure 3 As shown, each drive signal amplification circuit in this embodiment includes an NMOS transistor, a pull-down resistor, and a second operational amplifier;

[0054] The drain of the NMOS transistor is connected to the output terminal of the DAC voltage regulation circuit to receive the first drive signal output by the DAC voltage regulation circuit.

[0055] The gate of the NMOS transistor is connected to the output terminal of the MOS driving circuit, and the transistor switches to receive one of the two second driving signals with opposite phases output by the MOS driving circuit.

[0056] The source (S) terminal of the NMOS transistor is connected to the positive input terminal of the second operational amplifier and grounded through the pull-down resistor. The output terminal of the second operational amplifier outputs an AC drive signal to drive the liquid crystal.

[0057] The DAC1 signal output from the DAC voltage regulation circuit is connected to the drain of NMOS transistor Q1. The gate of Q1 is connected to the PWM_A+ or PWM_A- output from the MOS driver circuit. The source of Q1 is connected in parallel with a pull-down resistor R3, which is connected to the positive input terminal of the second operational amplifier U1A. The output terminal of U1A is connected to a push-pull circuit, which enhances the drive output capability.

[0058] Based on the above embodiments, such as Figure 3 As shown, each drive signal amplification circuit in this embodiment further includes a push-pull circuit. The push-pull circuit includes an NPN transistor and a PNP transistor. The bases of the NPN transistor and the PNP transistor are connected to the output terminal of the second operational amplifier. The emitters of the PNP transistor and the NPN transistor are combined to output an AC drive signal for driving the liquid crystal. The collectors of the PNP transistor and the NPN transistor are grounded.

[0059] The push-pull circuit consisting of PNP and NPN transistors connected to the output of the second operational amplifier can enhance the output driving capability. When the liquid crystal driving current is small, this part of the circuit can be omitted.

[0060] Based on the above embodiments, such as Figure 3 As shown, each drive signal amplification circuit in this embodiment further includes a feedback circuit, which includes a first resistor R4 and a second resistor R5.

[0061] One end of the first resistor R4 is connected to the output terminal of the second operational amplifier, and the other end is connected to the inverting input terminal of the second operational amplifier;

[0062] One end of the second resistor R5 is grounded, and the other end is connected to the inverting input of the second operational amplifier.

[0063] The output of the push-pull circuit is connected in parallel with R4 and R5 to form a feedback circuit, which forms a non-inverting operational amplifier circuit to realize the negative feedback and output amplification of the operational amplifier.

[0064] Based on the above embodiments, in this embodiment, when the second driving signal is high, the voltage of the NMOS transistor is greater than or equal to the MOS transistor turn-on voltage, the NMOS transistor is turned on, the voltage at the positive input terminal of the second operational amplifier is the voltage of the first driving signal, and the voltage at the output terminal of the driving signal amplification circuit is not 0;

[0065] When the second drive signal is low, the voltage of the NMOS transistor is less than the turn-on voltage of the MOS transistor, the NMOS transistor is turned off, the voltage at the positive input terminal of the second operational amplifier is pulled low by the pull-down resistor, and the voltage at the output terminal of the second operational amplifier is 0V.

[0066] When the second drive signal PWM_A+ is high, the V of the NMOS transistor Q1 in the drive signal amplifier circuit is... GS Greater than the MOSFET's on-state voltage V GS(TH) When MOSFET Q1 is turned on, the voltage at the positive input terminal of the second operational amplifier U1A is the voltage of DAC1. Since the source voltage of Q1 is equal to the voltage of DAC1 after Q1 is turned on, and the maximum value of DAC1 is 3.3V, the minimum value of VCC voltage in the MOSFET driver circuit must be greater than [a certain value].

[0067] V GS(TH) +3.3V.

[0068] When the second drive signal PWM_A+ is low, the NMOS transistor Q1 is turned off, and the positive input terminal of the second operational amplifier U1A is pulled down to GND by the pull-down resistor R3. Therefore, the output voltage of the operational amplifier U1 is 0V.

[0069] Therefore, the final driver can output a signal with the same frequency, duty cycle, and phase as PWM_A, and a voltage amplitude of [value missing]. A square wave, where V DAC1 The DAC_PWM outputs a voltage level with an amplitude of 0 to 3.3V based on its duty cycle.

[0070] By using another identical drive signal amplifier circuit, and changing the PWM_A+ signal to PWM_A-, a differential output voltage can be formed.

[0071] AC liquid crystal drive signal.

[0072] Because it needs to meet the maximum output level of the driver, and the maximum output level of the driver is

[0073] V DAC1 When the voltage is 3.3V, the power supply VDD voltage of the drive signal amplifier circuit must be greater than 3.3V. Only then can the maximum output level of the drive signal be met.

[0074] Based on the above embodiments, in this embodiment, when the second driving signal is high, the output voltage V of the driving signal amplification circuit is... OUT for:

[0075]

[0076] Among them, V IN The voltage at the positive input terminal of the second operational amplifier is equal to the voltage of the first drive signal, i.e., V. IN =V DAC1 R5 is the resistance value of the second resistor, and R4 is the resistance value of the first resistor.

[0077] Based on the relationship of the op-amp non-inverting amplifier circuit, the relationship between the drive output level and the voltage at the non-inverting input terminal can be derived, and the drive output voltage is: times V DAC1 .

[0078] Based on the above embodiments, in this embodiment, the maximum amplitude of the second driving signal is the power supply voltage, which is greater than the sum of the MOS transistor turn-on voltage of the NMOS transistor and the maximum voltage of the first driving signal.

[0079] In the MOS driver circuit, the PWM_A signal is generated by the MCU. PWM_A is connected to the non-inverting and inverting input terminals of the MOS driver IC, respectively. The driver IC outputs MOS drive signals PWM_A+ and PWM_A- with the same amplitude but opposite phase. The maximum amplitude of PWM_A+ and PWM_A- is the VCC voltage. Generally, the VCC voltage is selected within the range of the MOS transistor's voltage. GS(TH) +3.3V~V GS(MAX) .

[0080] like Figure 4 As shown, this utility model also provides a color-changing lamp, comprising:

[0081] Lamp head 1, wherein the lamp head 1 is provided with multiple light sources, each light source corresponding to a liquid crystal lens 11, and each liquid crystal lens 11 is controlled by the voltage control circuit of the lamp liquid crystal lens in any of the above embodiments;

[0082] Arm 2 is used to support the rotation of the lamp head 1;

[0083] The chassis 3 is used to support the rotation of the arm 2.

[0084] Because fewer control signals are required, when used for stage lighting color-changing lights, a MCU with fewer pins can generate multiple LCD drive signals. Each LED can use an LCD lens to achieve individual control of different fogging or magnification effects for each LED, producing more optical effects.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A voltage control circuit for a liquid crystal lens in a lamp, characterized in that, include: A DAC voltage regulation circuit is provided, the input of which is connected to the MCU of the stage lighting liquid crystal lens. The DAC voltage regulation circuit is used to process the first PWM signal output by the MCU to adjust the voltage amplitude of the liquid crystal driving the stage lighting liquid crystal lens and output the first driving signal. A MOS driving circuit, the input terminal of which is connected to the MCU, is used to generate two second driving signals with opposite phases according to the second PWM signal output by the MCU; Two drive signal amplification circuits are provided. The input terminal of each drive signal amplification circuit is connected to the output terminal of the DAC voltage regulation circuit and the output terminal of the MOS drive circuit. The two drive signal amplification circuits receive two second drive signals with opposite phases. The output terminal of each drive signal amplification circuit is connected to the stage lighting liquid crystal lens. Each drive signal amplification circuit is used to generate an AC drive signal to drive the liquid crystal based on the first drive signal and the second drive signal it receives.

2. The voltage control circuit for the liquid crystal lens of the lamp according to claim 1, characterized in that, The DAC voltage regulation circuit includes a voltage follower circuit and an RC filter circuit; The input terminal of the RC filter circuit is connected to the MCU to receive the first PWM signal output by the MCU. The output terminal of the RC filter circuit is connected to the positive input terminal of the first operational amplifier. The output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier to form the voltage follower circuit.

3. The voltage control circuit for the liquid crystal lens of the lamp according to claim 1, characterized in that, The MOS driving circuit includes a MOS driving IC; The positive and negative input terminals of the MOS driver IC are connected to the MCU to receive the second PWM signal output by the MCU. The output terminal of the MOS driver IC outputs two second drive signals with opposite phases.

4. The voltage control circuit for the liquid crystal lens of the lamp according to claim 1, characterized in that, Each drive signal amplification circuit includes an NMOS transistor, a pull-down resistor, and a second operational amplifier. The drain of the NMOS transistor is connected to the output terminal of the DAC voltage regulation circuit to receive the first drive signal output by the DAC voltage regulation circuit. The gate of the NMOS transistor is connected to the output terminal of the MOS driving circuit, and receives one of the two second driving signals with opposite phases output by the MOS driving circuit as a second driving signal. The source (S) terminal of the NMOS transistor is connected to the positive input terminal of the second operational amplifier and grounded through the pull-down resistor. The output terminal of the second operational amplifier outputs an AC drive signal to drive the liquid crystal.

5. The voltage control circuit for the liquid crystal lens of a lamp according to claim 4, characterized in that, Each drive signal amplification circuit further includes a push-pull circuit, which includes an NPN transistor and a PNP transistor. The bases of the NPN transistor and the PNP transistor are connected to the output terminal of the second operational amplifier. The emitters of the PNP transistor and the NPN transistor are combined to output an AC drive signal for driving the liquid crystal. The collectors of the PNP transistor and the NPN transistor are grounded.

6. The voltage control circuit for the liquid crystal lens of a lamp according to claim 4, characterized in that, Each drive signal amplification circuit also includes a feedback circuit, which includes a first resistor and a second resistor. One end of the first resistor is connected to the output terminal of the second operational amplifier, and the other end is connected to the inverting input terminal of the second operational amplifier; One end of the second resistor is grounded, and the other end is connected to the inverting input of the second operational amplifier.

7. The voltage control circuit for the liquid crystal lens of a lamp according to claim 6, characterized in that, When the second drive signal is high, the voltage of the NMOS transistor is greater than or equal to the MOS transistor turn-on voltage, the NMOS transistor is turned on, the voltage at the positive input terminal of the second operational amplifier is the voltage of the first drive signal, and the output voltage of the drive signal amplification circuit is not 0. When the second drive signal is low, the voltage of the NMOS transistor is less than the turn-on voltage of the MOS transistor, the NMOS transistor is turned off, the voltage at the positive input terminal of the second operational amplifier is pulled low by the pull-down resistor, and the voltage at the output terminal of the second operational amplifier is 0V.

8. The voltage control circuit for the liquid crystal lens of a lamp according to claim 7, characterized in that, When the second driving signal is high, the output voltage V of the driving signal amplifier circuit is... OUT for: Among them, V IN R5 is the voltage at the positive input terminal of the second operational amplifier, which is equal to the voltage of the first drive signal. R4 is the resistance value of the second resistor.

9. The voltage control circuit for the liquid crystal lens of a lamp according to claim 4, characterized in that, The maximum amplitude of the second driving signal is the power supply voltage, which is greater than the sum of the MOS transistor's turn-on voltage and the maximum voltage of the first driving signal.

10. A color-changing lamp, characterized in that, include: The lamp head is provided with multiple light sources, each light source corresponding to a liquid crystal lens, and each liquid crystal lens is controlled by the voltage control circuit of the liquid crystal lens of the lamp according to any one of claims 1-9. An arm for supporting the rotation of the lamp head; The chassis is used to support the rotation of the arm.

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