CN117031801A

CN117031801A - Driving circuit, shell assembly and electronic equipment

Info

Publication number: CN117031801A
Application number: CN202310814828.XA
Authority: CN
Inventors: 贺文钦; 黄松
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2022-01-15
Filing date: 2022-01-15
Publication date: 2023-11-10
Also published as: CN115542592B; CN115542592A

Abstract

The application provides a driving circuit, a housing assembly and an electronic device. The driving circuit is used for driving the light transmittance or color of the electrically variable layer to change. The driving circuit is used for receiving the first voltage signal, amplifying the first voltage signal and converting the first voltage signal into a first driving signal and a second driving signal with opposite phases. The first driving signal and the second driving signal are respectively output to two ends of the electrically-variable layer, so that the light transmittance or the color of the electrically-variable layer is driven to change correspondingly. The driving circuit provided by the application has a simple circuit structure and is suitable for various portable electronic equipment.

Description

Driving circuit, shell assembly and electronic equipment

The application is a divisional application of patent application No. 202210045576.4, application date 2022-01-15, application name of the patent application of 'driving circuit, housing component and electronic equipment'.

Technical Field

The present application relates to the field of display technologies, and in particular, to a driving circuit, a housing assembly, and an electronic device.

Background

Terminal products (e.g., mobile phones, notebook computers, etc.) often employ methods of attaching decorative films to the housing to enhance the overall aesthetics of the terminal product. However, with the homogenization of the decorative film effect, the appearance difference of the end product is smaller and smaller, and the aesthetic effect of the attached decorative film is smaller and smaller.

Some existing end products employ a housing covering a polymer dispersed liquid crystal film (Polymer Dispersed Liquid Crystal, hereinafter PDLC film) to create a variable decorative effect. However, PDLC films require high voltage ac power to produce varying decorative effects. Obviously, for some end products, especially portable electronic devices, it is difficult to generate corresponding high voltage ac-driven PDLC film changes as it is typically powered using a single lithium battery. As such, the use of PDLC films by end products is greatly limited.

Disclosure of Invention

In view of the above, the present application provides a driving circuit, a housing assembly and an electronic device to solve at least one of the above problems.

A first aspect of an embodiment of the present application provides a driving circuit for driving a change in light transmittance or color of an electrically variable layer. The driving circuit at least comprises a driving module. The driving module is used for receiving the first voltage signal, amplifying the first voltage signal and converting the first voltage signal into a first driving signal and a second driving signal with opposite phases. The first driving signal and the second driving signal are respectively output to two ends of the electrically-variable layer, so that the light transmittance or the color of the electrically-variable layer is driven to change correspondingly.

In the scheme provided by the embodiment of the application, the driving module is used for processing the input first voltage signal to generate the first driving signal and the second driving signal. The first driving signal and the second driving signal are also respectively output to two ends of the electrically variable layer. Wherein the first driving signal and the second driving signal are opposite in phase. Thus, the first driving signal and the second driving signal form equivalent alternating voltage signals at two ends of the electrically variable layer, so that the electrically variable layer is driven to generate corresponding changes.

In a possible implementation manner of the first aspect, the driving module includes a first driving unit and a second driving unit. The first driving unit and the second driving unit are used for receiving the first voltage signal. The first driving unit is used for amplifying and converting the received first voltage signal into a first driving signal, and the second driving unit is used for amplifying and converting the received first voltage signal into a second driving signal.

In the scheme provided by the embodiment of the application, the first voltage signal is amplified and converted into the first driving signal and the second driving signal with opposite phases through the first driving unit and the second driving unit.

In a possible implementation manner of the first aspect, the first driving unit includes a first amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor. The first amplifier comprises a first non-inverting input end, a first inverting input end and a first output end, one end of a first resistor is used for receiving a first voltage signal, and the other end of the first resistor is electrically connected to the first inverting input end; one end of the second resistor is electrically connected between the first resistor and the first inverting input end, and the other end of the second resistor is electrically connected to the first output end; one end of the third resistor is electrically connected to the first non-inverting input end, and the other end of the third resistor is electrically connected to the reference ground; one end of the fourth resistor is electrically connected between the third resistor and the first in-phase input end, and the other end of the fourth resistor is electrically connected to the reference ground; the first output terminal is used for outputting a first driving signal.

In a possible implementation manner of the first aspect, the second driving unit includes a second amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and an eighth resistor. The second amplifier comprises a second non-inverting input end, a second inverting input end and a second output end, one end of a fifth resistor is electrically connected to the reference ground, and the other end of the fifth resistor is electrically connected to the second inverting input end; one end of the sixth resistor is electrically connected between the fifth resistor and the second inverting input end, and the other end of the sixth resistor is electrically connected to the second output end; one end of the seventh resistor is electrically connected to the second non-inverting input end, and the other end of the seventh resistor is used for receiving the first voltage signal; one end of the eighth resistor is electrically connected between the seventh resistor and the second non-inverting input end, and the other end of the eighth resistor is electrically connected to the reference ground; the second output end is used for outputting a second driving signal.

In the scheme provided by the embodiment of the application, the first amplifier, the second amplifier and the resistors are arranged to form the positive feedback first driving unit and the negative feedback second driving unit, and the first driving unit and the second driving unit amplify and convert the first voltage signal to generate the first driving signal and the second driving signal with opposite phases.

In a possible implementation manner of the first aspect, the driving circuit further includes a filtering module, and the filtering module is electrically connected to an input terminal of the driving module, and is configured to receive the pwm signal, filter the pwm signal to generate a first voltage signal, and output the first voltage signal to the driving module.

In the scheme provided by the embodiment of the application, the filtering module is arranged to correspondingly adjust the waveforms of the pulse width modulation signals so as to generate the first voltage signals, thereby further adjusting the waveforms of the first driving signals and the second driving signals.

In a possible implementation manner of the first aspect, the driving circuit further includes a control chip, and the control chip is configured to control a duty cycle of the pwm signal to adjust a waveform of the first voltage signal, so as to control frequencies and waveforms of the first driving signal and the second driving signal.

In the scheme provided by the embodiment of the application, the duty ratio of the pulse width modulation signal is directly controlled by the control chip, so that the waveform of the first voltage signal is adjusted, and the frequency and the waveform of the first driving signal and the second driving signal are controlled.

In a possible implementation manner of the first aspect, the driving circuit further includes a boost module, one end of the boost module is electrically connected to the power supply unit, the other end of the boost module is electrically connected to the driving module, and the boost module is configured to boost a voltage output by the power supply unit to generate a second voltage signal, and output the second voltage signal to a power input end of the driving module to supply power to the driving module.

In the scheme provided by the embodiment of the application, the voltage output by the power supply unit is boosted by the boosting module so as to meet the power supply requirement of the driving module.

In a possible implementation manner of the first aspect, the driving circuit further includes a control chip, the boost module includes a boost unit, a sampling unit and a comparison unit, wherein one end of the boost unit is electrically connected to the power supply unit, and is used for performing boost processing on a voltage output by the power supply unit to generate a second voltage signal, the sampling unit is electrically connected to an output end of the boost unit, and is used for sampling the second voltage signal to obtain a sampling voltage, the comparison unit is electrically connected to the sampling unit and the control chip, and is used for comparing the sampling voltage with a reference voltage, and outputting a judging result to the control chip, and the control chip controls the magnitude of the second voltage signal output by the boost unit according to the judging result, so as to stabilize the second voltage signal.

In the scheme provided by the embodiment of the application, the second voltage signal output by the boosting module is stabilized by arranging the boosting unit, the sampling unit and the comparison unit, so that stable power supply is provided for the driving module.

In a possible implementation manner of the first aspect, the boost unit includes an inductor, a first electronic switch and a second electronic switch, one end of the inductor is electrically connected to the power supply unit, the other end of the inductor is electrically connected to a first end of the first electronic switch and a first end of the second electronic switch, a second end of the first electronic switch is electrically connected to a ground reference, a third end of the first electronic switch is electrically connected to the control chip, a third end of the second electronic switch is electrically connected to the control chip, and a second end of the second electronic switch is electrically connected to the driving module. The control chip controls the first electronic switch to be turned on in a first preset time and the second electronic switch to be turned off in the first preset time, so that the inductor stores the voltage output by the power supply unit. The control chip further continuously controls the second electronic switch to be opened in a second preset time, and controls the first electronic switch to be opened in the second preset time, so that the inductor outputs a second voltage signal to the driving module through the second electronic switch.

In the scheme provided by the embodiment of the application, the first electronic switch is controlled to be turned on and the second electronic switch is controlled to be turned off through the control chip so as to control the voltage output by the inductance storage power supply unit to be boosted, and then the first electronic switch is controlled to be turned off and the second electronic switch is controlled to be turned on through the control chip so as to control the inductance to discharge to the driving module.

In a possible implementation manner of the first aspect, the sampling unit includes a first sampling resistor and a second sampling resistor. One end of the first sampling resistor is electrically connected to the second end of the second electronic switch, the other end of the first sampling resistor is electrically connected to one end of the second sampling resistor, and the other end of the second sampling resistor is electrically connected to the reference ground. The comparison unit comprises a comparator and a reference voltage source. The comparator comprises a first input end, a second input end and an output end, wherein the first input end is an inverting input end, the second input end is an in-phase input end, the first input end is electrically connected between the first sampling resistor and the second sampling resistor, the second input end is electrically connected to the positive electrode of a reference voltage source, the negative electrode of the reference voltage source is electrically connected to a reference ground, and the output end is electrically connected to a control chip and is used for outputting a comparison result to the control chip. The control chip further controls the duty ratio of the first electronic switch and the second electronic switch according to the comparison result, so that the voltage amplitude of the second voltage signal output by the boosting module is adjusted.

In the scheme provided by the embodiment of the application, the sampling unit and the comparison unit are arranged in the boosting module, so that the second voltage signal is stabilized.

In a possible implementation manner of the first aspect, the sampling unit further includes a sampling capacitor, one end of which is electrically connected between the second end of the second electronic switch and the first sampling resistor, and the other end of which is electrically connected to the reference ground.

In the scheme provided by the embodiment of the application, the sampling capacitor is arranged to store the voltage, so that the sampling capacitor continuously provides the voltage output when the second electronic switch is disconnected.

A second aspect of an embodiment of the present application provides a housing assembly comprising a housing, and a drive circuit as defined in any one of the above. The shell at least comprises an electrically-variable layer, and the driving circuit is electrically connected to the electrically-variable layer to respectively output a first driving signal and a second driving signal to two ends of the electrically-variable layer.

In the scheme provided by the embodiment of the application, the driving circuit is electrically connected to the electrically-variable layer of the shell, so that the electrically-variable layer presents different states.

In a possible implementation manner of the second aspect, the electrically variable layer includes a first electrode layer, a dielectric layer, and a second electrode layer that are sequentially stacked, one of the first electrode layer and the second electrode layer is configured to receive the first driving signal, and the other of the second electrode layer and the second electrode layer is configured to receive the second driving signal.

In the scheme provided by the embodiment of the application, the first electrode layer and the second electrode layer are respectively arranged at two sides of the dielectric layer, so that the first driving signal and the second driving signal are led in at two sides of the dielectric layer, and the dielectric layer is in different states in the power-on state and the power-off state.

In one possible embodiment of the second aspect, the dielectric layer comprises a polymer dispersed liquid crystal film or a polymer network liquid crystal film.

In the scheme provided by the embodiment of the application, the polymer dispersed liquid crystal film or the polymer network liquid crystal film is arranged in the dielectric layer, so that the dielectric layer is in different states under the power-on state and the power-off state.

In a possible implementation manner of the second aspect, the housing further includes at least a substrate layer and a protective layer, one of the first electrode layer and the second electrode layer is disposed between the substrate layer and the dielectric layer, and the other of the first electrode layer and the second electrode layer is disposed between the dielectric layer and the protective layer.

In the scheme provided by the embodiment of the application, the substrate layer is arranged and used for supporting the electrically-variable layer; by providing a protective layer, wear of the electrically variable layer is reduced.

A third aspect of an embodiment of the present application provides an electronic device, including a housing, and a driving circuit as set forth in any one of the above. The housing further includes an electrically variable layer, and the driving circuit is electrically connected to both ends of the electrically variable layer.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly describe the drawings in the embodiments, it being understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a circuit diagram of a prior art driving circuit;

FIG. 2 is a schematic diagram of an electronic device according to an embodiment of the application;

FIG. 3 is a partially disassembled schematic illustration of the electronic device shown in FIG. 2;

FIG. 4 is a partial cross-sectional view of the rear cover of the electronic device of FIG. 3;

FIG. 5A is a schematic view of a first state of the dielectric layer of the back cover of FIG. 3 when the dielectric layer includes a PDLC film;

FIG. 5B is a schematic diagram of a second state of the dielectric layer of the back cover of FIG. 3 when the dielectric layer includes a PDLC film;

FIG. 6 is a circuit block diagram of a driving circuit according to an embodiment of the present application;

FIG. 7 is a schematic circuit diagram of a driving circuit according to an embodiment of the present application;

FIG. 8A is a schematic diagram of a voltage waveform of the PWM signal in the driving circuit shown in FIG. 7;

FIG. 8B is a schematic diagram of a voltage waveform of a first voltage signal in the driving circuit shown in FIG. 7;

FIG. 9 is a schematic diagram of voltage waveforms of the first voltage signal, the first driving signal and the second driving signal according to an embodiment of the present application;

fig. 10 is a schematic voltage waveform diagram of the equivalent driving voltages at two ends of the first driving signal, the second driving signal and the electro-variable layer according to an embodiment of the application.

Description of main reference numerals:

an electronic device 100; a display screen 11; a middle frame 12; a main body 121; a frame 122; battery 13

A power supply unit 131; a circuit board 14; a power management module 141; a rear cover 15; substrate layer 151

An electrically variable layer 152; a first electrode layer 1521; a dielectric layer 1522; second electrode layer 1523

A protective layer 153; a driving circuit 20; a filtering module 21; a filter resistor R9; filter capacitor C1

A coupling capacitor C2; a drive module 22; a first driving unit 221; first amplifier OPA1

A first in-phase input INT1+; a first inverting input terminal INT1-; a first output terminal OUT1

A first power supply input terminal SOU1; a first ground GND1; a first resistor R1; second resistor R2

A third resistor R3; a fourth resistor R4; a second driving unit 222; second amplifier OPA2

A second non-inverting input INT2+; a second inverting input INT2-; a second output terminal OUT2

A second power supply input terminal SOU2; a second ground GND2; a fifth resistor R5; sixth resistor R6

A seventh resistor R7; an eighth resistor R8; a boosting module 23; a boosting unit 231; inductance L1

A first electronic switch M1; a second electronic switch M2; first ends D1, D2; second ends S1, S2

Third terminals G1, G2; a sampling unit 232; a first sampling resistor R11; second sampling resistor R12

A sampling capacitor C3; a comparison unit 233; a comparator COM; first input end 2331

A second input 2332; an output 2333; a reference voltage source REF; control chip 24

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or/and" as used herein includes any and all combinations of one or more of the associated listed items.

Some embodiments of the application are described in detail. The following embodiments and features of the embodiments may be combined with each other without collision.

It is understood that with the popularity of electronic devices such as mobile phones, tablet computers, and notebook computers, the aesthetic appearance of the housing of the electronic device will directly affect the purchasing desire of consumers. Currently, the color of the housing of an electronic device is generally fixed. Therefore, on one hand, the shell of the existing mobile terminal is more and more homogeneous, and on the other hand, the requirements of consumers on the attractiveness of the mobile terminal cannot be met.

To achieve interaction between the apparent color of the electronic device and the user, the electronic device forms a variable decorative effect on the housing by covering the housing with an electrically variable layer, such as a polymer dispersed liquid crystal film. However, the electrically variable layer is driven with a high voltage alternating current to produce a varying decorative effect.

Referring to fig. 1, currently, some known solutions use a transformer to step down the high-voltage ac to drive the electrically variable layer. However, when the electronic device has only a direct current power source, for example, a lithium battery capable of outputting only direct current, this solution is obviously difficult to realize due to the lack of an alternating current power source. In some technical schemes, the direct-current voltage signal is converted into the alternating-current voltage signal by boosting and then forming an inverter circuit by using an MOS tube, however, the circuit structure of the technical scheme is complex, and the random adjustment of the driving waveform is difficult to realize.

To this end, an embodiment of the present application provides an electronic device 100, including a driving circuit 20. The driving circuit 20 is configured to output a driving signal to cause a corresponding change in the housing of the electronic device 100.

It is understood that the electronic device 100 in the embodiment of the present application may include, but is not limited to, a mobile terminal or a fixed terminal such as a mobile phone, a tablet computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, an interphone, a netbook, a Point of sale (POS) machine, a personal digital assistant (personal digital assistant, PDA), a wearable device, a virtual reality device, a wireless U-disc, a bluetooth sound/earphone, a vehicle-mounted device, a car recorder, a security device, or a medical device.

It will be appreciated that the following embodiments do not limit the specific form of the electronic device 100, and only the electronic device 100 is used as a mobile phone to describe how the electronic device 100 implements the specific technical solution in the embodiments.

Referring to fig. 2 and 3, the electronic device 100 includes a display 11, a middle frame 12, a battery 13, a circuit board 14 and a rear cover 15. The display 11 and the rear cover 15 are respectively located at two sides of the middle frame 12. And the rear cover 15 is covered on one side of the middle frame 12. The display 11 is accommodated in an opening of the middle frame 12 on a side away from the rear cover 15. In this way, between the display 11 and the middle frame 12, a housing space for housing various functional devices and electronic devices can be formed between the middle frame 12 and the rear cover 15.

A battery 13 and a circuit board 14 may be provided on the center 12. Specifically, the battery 13 may be disposed on a side of the middle frame 12 near the display screen 11, or on a side of the middle frame 12 near the rear cover 15. The circuit board 14 may also be disposed on a side of the middle frame 12 near the display screen 11, or on a side of the middle frame 12 near the rear cover 15.

It will be appreciated that the circuit board 14 is provided with a corresponding power management module 141 and a charging management module (not shown). The battery 13 is electrically connected to the charge management module through the power management module 141. It will be appreciated that the power management module 141 receives input from the battery 13 and/or the charge management module to power the processor, internal memory, external memory, display 11, camera module, and communication module, etc. The power management module 141 may also monitor the capacity of the battery 13, the number of cycles of the battery 13, the state of health (leakage, impedance) of the battery 13, etc. It is understood that in other embodiments, the power management module 141 may be disposed on another separate circuit board.

The middle frame 12 includes a main body 121 and a frame 122. The main body 121 is a substantially square plate. The frame 122 is disposed around the periphery of the main body 121 and is disposed perpendicular to the main body 121. It will be appreciated that the body 121 and the frame 122 may be clamped, welded, adhered or integrally formed, or the body 121 and the frame 122 may be fixedly connected by injection molding.

It will be appreciated that when the rear cover 15 is closed to the middle frame 12, the rear cover 15 and the rim 122 are in contact with each other. It will be appreciated that in some embodiments, the rear cover 15 may also be integrally formed with the bezel 122 and serve as a housing for the electronic device 100.

With continued reference to fig. 4, in some embodiments, the rear cover 15 includes a substrate layer 151, an electrically variable layer 152, and a protective layer 153 that are stacked. Wherein the back cover 15 assumes a first state, such as an opaque state, when the electrically variable layer 152 is in a powered off state. When the electrically variable layer 152 is in the energized state, the back cover 15 assumes a second state, such as a transparent state.

It will be appreciated that the application is not limited to the material of the substrate layer 151, for example, the substrate layer 151 may be made of glass, plastic, or ceramic. The substrate layer 151 is used to support the electrically variable layer 152 and the protective layer 153 on the one hand, and to provide insulation protection for the electrically variable layer 152 on the other hand. It will be appreciated that in some embodiments, when the substrate layer 151 is made of a metallic material, a layer of insulating material is also provided between the substrate layer 151 and the electrically variable layer 152.

The protective layer 153 covers the surface of the electrically variable layer 152, and is used to reduce abrasion loss of the electrically variable layer 152 and to provide protection for the electrically variable layer 152. It is understood that the protective layer 153 may be made of a transparent insulating material.

In some embodiments, the electrically variable layer 152 includes a first electrode layer 1521, a dielectric layer 1522, and a second electrode layer 1523 that are stacked in this order. The first electrode layer 1521 and the second electrode layer 1523 are disposed on two sides of the dielectric layer 1522, respectively, so as to serve as electrodes on two ends of the dielectric layer 1522 for introducing an ac voltage to the dielectric layer 1522.

It is understood that one of the first electrode layer 1521 and the second electrode layer 1523 is disposed between the substrate layer 151 and the dielectric layer 1522, and the other of the first electrode layer 1521 and the second electrode layer 1523 is disposed between the dielectric layer 1522 and the protective layer 153.

In some embodiments, the first electrode layer 1521 and the second electrode layer 1523 are made of transparent conductive materials. For example, the first electrode layer 1521 and the second electrode layer 1523 may be made of Indium Tin Oxide (ITO), nano silver paste, or metal oxide. The dielectric layer 1522 includes a polymer dispersed liquid crystal film (Polymer Dispersed Liquid Crystal, hereinafter referred to as PDLC film) or a polymer network liquid crystal film (Polymer Network Liquid Crystal, hereinafter referred to as PNLC film).

Referring to fig. 5A, it can be understood that the PDLC film is a film in which liquid crystal is dispersed in an organic solid polymer matrix in small droplets on the order of micrometers. Under the condition that alternating voltage is not introduced, the optical axes of the small droplets formed by the liquid crystal molecules are in free orientation, the refractive index of the small droplets is not matched with that of the matrix, the liquid crystal molecules which are distributed randomly scatter incident light, so that the incident light is strongly scattered by the liquid crystal droplets when entering the matrix, and the PDLC film is in an opaque and milky state. Referring to fig. 5B, since the liquid crystal molecules are very susceptible to the applied electric field to generate induced charges, when an electrostatic field (for example, an electrostatic field with voltage VH) is applied to the liquid crystal, the induced charges generate electrostatic torque, so that the liquid crystal molecules are aligned, and the incident light can freely penetrate the PDLC film, thereby exhibiting transparent optical effect. Thus, the optical axis orientation of the liquid crystal droplets can be adjusted by applying an electric field. When an alternating current is applied to the PDLC film, the arrangement of the liquid crystal molecules changes, allowing incident light to transmit through the PDLC film with little scattering, so that the PDLC film assumes a transparent state. After the applied electric field is removed, the liquid crystal microdroplets recover the original astigmatic state, and the PDLC film is in an opaque 'milky' state. In this way, the PDLC film can change transparency according to the energization state.

It will be appreciated that the liquid crystals in PNLC films (not shown) are not spherical (or ellipsoidal) droplets, but rather are distributed in a three-dimensional network of polymers, forming a continuous network of channels, in contrast to PDLC films. Similar to PDLC films, PNLC films are opaque when they are powered off because incident light is strongly scattered and does not pass through the PNLC film. Under the condition of applying a certain alternating voltage, the liquid crystal molecules with dielectric anisotropy are subjected to the torque action of an electric field, the direction of directors of the liquid crystal molecules is kept in the same direction as the electric field, and incident light can penetrate through the PNLC film, and the PNLC film is in a transparent or semitransparent state.

It will be appreciated that in some embodiments, due to the difference in the voltages applied across the dielectric layer 1522 (i.e., the PDLC film or the PNLC film), the transmittance of the dielectric layer 1522 is different, and the color of the base material layer 151 and/or the protective layer 153 is combined, so that the rear cover 15 generates different color changes.

It is appreciated that in some embodiments, the dielectric layer 1522 may be made of other materials, such that when the voltage across the dielectric layer 1522 changes, the color of the dielectric layer 1522 itself changes accordingly.

However, the Peak-to-Peak Voltage (VPP) of the Voltage required to drive the dielectric layer 1522 is high and needs to be an ac Voltage. For example, in some embodiments, the voltage driving the PDLC film needs to be 30-50vpp and the frequency needs to be 50Hz.

It can be understood that referring to fig. 6, the electronic device 100 provided by the present application further includes a driving circuit 20. The driving circuit 20 has one end electrically connected to the power management module 141 and the other end electrically connected to the electro-variable layer 152, and is configured to convert a received pulse width modulation (Pulse Width Modulation, PWM) signal into a corresponding driving signal to drive the electro-variable layer 152 to generate a corresponding change in light transmittance or color.

It can be appreciated that the driving circuit 20 provided in the embodiment of the present application is particularly suitable for a device having only a dc power source, and can convert a dc signal into the first driving signal VD1 and the second driving signal VD2 with opposite phases, so that the first driving signal VD1 and the second driving signal VD2 are equivalent to ac signals together, thereby driving the electrically variable layer 152 to generate corresponding changes.

It is appreciated that in some embodiments, the driving circuit 20 may be electrically connected to the first electrode layer 1521 and the second electrode layer 1523 of the rear cover 15 through a flexible circuit board or a spring sheet (not shown).

With continued reference to fig. 7, in some embodiments, the driving circuit 20 includes a filtering module 21, a driving module 22, a boosting module 23, and a control chip 24. The filtering module 21 is configured to receive the PWM signal and perform filtering processing on the received PWM signal to output a first voltage signal V1 to the driving module 22. It can be appreciated that the filtering module 21 adjusts the frequency, amplitude and waveform of the received PWM signal by performing filtering processing on the PWM signal to obtain the first voltage signal V1, so as to facilitate the subsequent conversion of the first voltage signal V1 into the first driving signal VD1 and the second driving signal VD2 capable of driving the electrically variable layer 152. The driving module 22 is electrically connected to the filtering module 21, and is configured to receive the first voltage signal V1, amplify the first voltage signal V1, and convert the first voltage signal V1 into a first driving signal VD1 and a second driving signal VD2 with opposite phases. In this way, the first driving signal VD1 and the second driving signal VD2 are respectively output to two ends of the electrically variable layer 152 (i.e., the first electrode layer 1521 and the second electrode layer 1523), so as to drive the electrically variable layer 152 to change accordingly.

The boosting module 23 has one end electrically connected to the power supply unit 131 and the other end electrically connected to the driving module 22. The voltage boosting module 23 is configured to process, for example boost, the voltage output by the power supply unit 131 to output a second voltage signal V2 to the power input terminal of the driving module 22, so as to supply power to the driving module 22.

It is understood that the power supply unit 131 may be the battery 13, or may be other modules or ports for supplying or outputting electric power in the electronic device 100.

The control chip 24 is used for controlling the duty ratio of the PWM signal to adjust the waveform of the first voltage signal V1, and further controlling the frequency and waveform of the first driving signal VD1 and the second driving signal VD2, so as to realize a plurality of changes of the electrically variable layer 152. In the present embodiment, the control chip 24 is electrically connected to the power management module 141 to control the frequency and amplitude of the PWM signal outputted by the power management module 141. The control chip 24 is further electrically connected to the boost module 23, for stabilizing the second voltage signal V2 output by the boost module 23. It is understood that in some embodiments, the control Chip 24 may be a System on Chip (SoC) of the electronic device 100.

With continued reference to fig. 7, in some embodiments, an input terminal of the filtering module 21 is electrically connected to a General-purpose input/output (GPIO) interface of the power management module 141, for receiving the PWM signal output by the power management module 141.

It will be appreciated that the filtering module 21 comprises several filtering elements for adjusting the received PWM signal to the first voltage signal V1. For example, in some embodiments, the number of filter elements includes a filter resistor R9, a filter capacitor C1, and a coupling capacitor C2. One end of the filter resistor R9 is electrically connected to the GPIO interface of the power management module 141, and the other end of the filter resistor R9 is electrically connected to the filter capacitor C1. The other end of the filter capacitor C1 is electrically connected to the reference ground. One end of the coupling capacitor C2 is electrically connected between the filter resistor R9 and the filter capacitor C1, and the other end is electrically connected to the driving module 22, so as to output the first voltage signal V1 to the driving module 22.

Referring to fig. 8A and 8B together, it can be understood that the filter resistor R9, the filter capacitor C1 and the coupling capacitor C2 together form an RC filter circuit for filtering the high-frequency signal in the PWM signal, so that the obtained first voltage signal V1 initially meets the frequency requirement of the voltage capable of driving the electro-variable layer 152. For example, in some embodiments, the filtering module 21 is configured to adjust a PWM signal having a frequency of 5000 hertz to a sine wave signal having a frequency of 50 hertz.

It will be appreciated that the present application does not limit the waveform of the first voltage signal V1. For example, in other embodiments, the RC filter circuit formed by the filter resistor R9, the filter capacitor C1 and the coupling capacitor C2 can also convert the PWM signal of the square wave into other waveforms such as trapezoidal wave or triangular wave.

It will be appreciated that in other embodiments, the filter module 21 may be replaced by a digital-to-analog converter (Digital to Analog Convertor, DAC). Thus, the control chip 24 can directly control the voltage output by the digital-to-analog converter to meet the frequency requirement of the voltage that can drive the electro-variable layer 152. Thus, the digital-to-analog converter can directly output the voltage signal to the driving module to amplify and convert the voltage signal into the corresponding first driving signal VD1 and the second driving signal VD2.

It can be appreciated that, compared to setting up a digital-to-analog converter, the embodiment of the application filters the PWM signal by setting up the filtering module 21, so as to effectively and rapidly generate the first voltage signal V1, thereby saving the corresponding digital-to-analog converter and reducing the manufacturing cost.

It is understood that in other embodiments, the filtering module 21 may be electrically connected to other modules or ports capable of outputting PWM signals. For example, in some embodiments, an input of the filtering module 21 is electrically connected to the power management module 141 to receive the PWM signal output by the power management module 141. In other embodiments, the filtering module 21 may also be electrically connected to other electronic devices of the electronic apparatus 100, such as the control chip 24, a Codec (COder-DECoder), etc., to receive the PWM signal.

With continued reference to fig. 7, in some embodiments, the driving module 22 includes a first driving unit 221 and a second driving unit 222. The first driving unit 221 and the second driving unit 222 are electrically connected to the input end of the filtering module 21, and are configured to receive the first voltage signal V1 respectively, amplify and convert the received first voltage signal V1 to generate a corresponding first driving signal VD1 and a corresponding second driving signal VD2, and the phases of the first driving signal VD1 and the second driving signal VD2 are opposite.

In some embodiments, the first driving unit 221 includes a first amplifier OPA1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The first amplifier OPA1 includes a first inverting input terminal INT1-, a first non-inverting input terminal INT1+, a first output terminal OUT1, a first power input terminal SOU1, and a first ground terminal GND1.

One end of the first resistor R1 is electrically connected to the output end of the filter module 21, i.e. the coupling capacitor C2 of the filter module 21, and the other end of the first resistor R1 is electrically connected to the first inverting input terminal INT 1-of the first amplifier OPA 1. One end of the second resistor R2 is electrically connected between the first resistor R1 and the first inverting input terminal INT1-, and the other end is electrically connected to the first output terminal OUT1. The third resistor R3 has one end electrically connected to the first non-inverting input terminal INT1+, and the other end electrically connected to the reference ground. One end of the fourth resistor R4 is electrically connected between the third resistor R3 and the first non-inverting input terminal INT1+, and the other end is electrically connected to the reference ground. The first power input terminal SOU1 is electrically connected to the output terminal of the boosting module 23. The first ground GND1 is electrically connected to the ground. The first output terminal OUT1 is also electrically connected to the electro-variable layer 152. Specifically, in the present embodiment, the first output terminal OUT1 is also electrically connected to the first electrode layer 1521. The resistance of the first resistor R1 is equal to the resistance of the third resistor R3, and the resistance of the second resistor R2 is equal to the resistance of the fourth resistor R4.

It is understood that the first driving unit 221 forms a proportional operational amplifier circuit. Thus, in the first driving unit 221, a formula can be obtained

Wherein,

R1＝R3 ，R2＝R4 (3)

and according to the virtual short principle of the amplifier, can obtain

V _a ＝V _b (4)

Sorting the formulas (1) - (4) to obtain

I.e.

In the present embodiment, the second driving unit 222 includes a second amplifier OPA2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The second amplifier OPA2 includes a second inverting input terminal INT2-, a second non-inverting input terminal INT2+, a second output terminal OUT2, a second power input terminal SOU2, and a second ground terminal GND2. One end of the fifth resistor R5 is electrically connected between the third resistor R3 and the reference ground, and the other end of the fifth resistor R5 is electrically connected to the second inverting input terminal INT2-. One end of the sixth resistor R6 is electrically connected between the fifth resistor R5 and the second inverting input terminal INT2-, and the other end of the sixth resistor R6 is electrically connected to the second output terminal OUT2. The seventh resistor R7 has one end electrically connected to the second non-inverting input terminal INT2+, and the other end electrically connected between the coupling capacitor C2 and the first resistor R1 (i.e. receiving the first voltage signal V1). One end of the eighth resistor R8 is electrically connected between the seventh resistor R7 and the second non-inverting input terminal INT2+, and the other end is electrically connected to the ground. The second power input terminal SOU2 is electrically connected to the output terminal of the boost module 23. The second ground GND2 is electrically connected to the ground. The second output terminal OUT2 is also electrically connected to the electro-variable layer 152. Specifically, in the present embodiment, the second output terminal OUT2 is also electrically connected to the second electrode layer 1523. The resistance of the fifth resistor R5 and the resistance of the seventh resistor R7 are equal to the resistance of the first resistor R1, and the resistance of the sixth resistor R6 and the resistance of the eighth resistor R8 are equal to the resistance of the second resistor R2.

It is understood that the second driving unit 222 also forms a proportional operational amplifier circuit. In the second drive unit 222, similar to the analysis process of the first drive unit 211, it is possible to obtain

Also in the embodiment of the application, V0 is electrically connected to the reference ground, so

In this way, the first driving unit 221 and the second driving unit 222 amplify the first voltage signal V1 respectively, and the voltages of the first driving signal VD1 and the second driving signal VD2 obtained by conversion are equal in magnitude and opposite in phase. That is, in the driving circuit 20 provided in the embodiment of the present application, the first driving unit 221 amplifies the waveform of the lower half period (i.e., the phase interval is 180 degrees to 360 degrees) of the first voltage signal V1 in one period, and the second driving unit 222 amplifies the waveform of the upper half period (i.e., the phase interval is 0 degrees to 180 degrees) of the first voltage signal V1 in one period.

Fig. 9 and fig. 10 are schematic diagrams of waveforms of the first voltage signal V1, the first driving signal VD1 and the second driving signal VD2 according to an embodiment of the present application. Fig. 10 is a waveform diagram of equivalent driving voltages at two ends of the first driving signal VD1, the second driving signal VD2 and the electro-variable layer 152 according to an embodiment of the present application. In fig. 9, a curve S91 represents the voltage waveform of the first voltage signal V1, a curve S92 represents the voltage waveform of the first driving signal VD1, and a curve S93 represents the voltage waveform of the second driving signal VD 2. In fig. 10, a curve S101 represents the voltage waveform of the first drive signal VD1, a curve S102 represents the voltage waveform of the second drive signal VD2, and a curve S103 represents the voltage waveform of the equivalent drive voltage across the electrically variable layer 152.

As shown in fig. 9 and 10, it can be seen that the phase of the first driving signal VD1 generated by the first driving unit 221 amplifying the first voltage signal V1 is opposite to the phase of the second driving signal VD2 generated by the second driving unit 222 amplifying the first voltage signal V1. Thus, the first driving signal VD1 and the second driving signal VD2 can form an equivalent ac voltage signal at both ends of the electro-variable layer 152, and the equivalent amplification factor of the driving module 22 is that

Referring to fig. 9 again, the peak-to-peak value of the first driving signal VD1 and the peak-to-peak value of the second driving signal VD2 are half of the peak-to-peak value of the equivalent ac voltage signal. In this way, compared with the existing driving circuit for generating the ac voltage signal, the voltage withstand value of each electronic device in the driving circuit 20 provided by the embodiment of the application may be half of the voltage withstand value of the electronic device in the driving circuit for generating the ac voltage signal. That is, the driving circuit 20 provided in the embodiment of the application can greatly reduce the voltage withstand requirement of the electronic device and increase the circuit safety.

It should be understood that, in the embodiment of the present application, the voltage magnitudes and waveforms shown in fig. 8A-10 are merely used to illustrate the voltage signals in the embodiment of the present application, and are not limited to the voltage magnitudes and waveforms mentioned in the embodiment of the present application.

Referring to fig. 7 again, in some embodiments, the boosting module 23 includes a boosting unit 231, a sampling unit 232, and a comparing unit 233 electrically connected to each other. Wherein, one end of the boost unit 231 is electrically connected to the power supply unit 131, for boosting the voltage output by the power supply unit 131. The sampling unit 232 is electrically connected to an output terminal of the boost unit 231, and is configured to sample the voltage output by the boost unit 231 to obtain a sampled voltage. The comparing unit 233 is electrically connected to the sampling unit 232 and the control chip 24, and is configured to compare the sampled voltage with a reference voltage and output a determination result to the control chip 24. The control chip 24 is used for controlling the boost unit 231 to boost according to the judgment result, so as to stabilize the voltage amplitude of the second voltage signal V2 output by the boost module 23.

Specifically, in some embodiments, the boost unit 231 includes an inductor L1, a first electronic switch M1, and a second electronic switch M2. The first electronic switch M1 is an N-Metal-Oxide-Semiconductor (NMOS) transistor. The second electronic switch M2 is a P-Metal-Oxide-Semiconductor (PMOS) transistor. The first electronic switch M1 includes a first terminal D1 (drain), a second terminal S1 (source), and a third terminal G1 (gate). The second electronic switch M2 includes a first terminal D2 (drain), a second terminal S2 (source), and a third terminal G2 (gate). One end of the inductor L1 is electrically connected to the power supply unit 131, and the other end is electrically connected to the first end D1 of the first electronic switch M1 and the first end D2 of the second electronic switch M2. The second terminal S1 of the first electronic switch M1 is electrically connected to the ground. The third terminal G1 of the first electronic switch M1 is electrically connected to the control chip 24. The third terminal G2 of the second electronic switch M2 is electrically connected to the control chip 24. The second terminal S2 of the second electronic switch M2 is electrically connected to the driving module 22, and is configured to output a second voltage signal V2 to supply power to the driving module 22.

In some embodiments, the sampling unit 232 includes a first sampling resistor R11, a second sampling resistor R12, and a sampling capacitor C3. One end of the first sampling resistor R11 is electrically connected to the second end S2 of the second electronic switch M2, and the other end is electrically connected to one end of the second sampling resistor R12. The other end of the second sampling resistor R12 is electrically connected to the reference ground. Thus, the first sampling resistor R11 and the second sampling resistor R12 together form a sampling circuit for sampling the voltage output by the second end S2 of the second electronic switch M2. One end of the sampling capacitor C3 is electrically connected between the second end S2 of the second electronic switch M2 and the first sampling resistor R11, and the other end of the sampling capacitor C3 is electrically connected to the reference ground. The sampling capacitor C3 is used for storing a voltage to continuously supply power to the driving module 22 when the second electronic switch M2 is turned off.

In some embodiments, the comparison unit 233 includes a comparator COM and a reference voltage source REF. The comparator COM includes a first input terminal 2331, a second input terminal 2332, and an output terminal 2333. The first input terminal 2331 is an inverting input terminal, and the second input terminal 2332 is a non-inverting input terminal. The first input terminal 2331 is electrically connected between the first sampling resistor R11 and the second sampling resistor R12. The second input 2332 is electrically connected to the positive pole of the reference voltage source REF. The negative pole of the reference voltage source REF is electrically connected to the reference ground. In this way, the comparator COM measures whether the voltage output by the second electronic switch M2 reaches the voltage amplitude of the preset second voltage signal V2 by comparing the voltages of the first input end 2331 and the second input end 2332. The output terminal of the comparator COM is electrically connected to the control chip 24, and is used for outputting the comparison result to the control chip 24. In this way, the control chip 24 can further control the duty ratio of the first electronic switch M1 and the second electronic switch M2 according to the comparison result, so as to adjust the voltage amplitude of the second voltage signal V2 output by the boost module 23 to reach the preset voltage amplitude.

It can be appreciated that the operating principle of the boost module 23 is generally as follows:

the control chip 24 controls the first electronic switch M1 to be turned on in a first preset time and the second electronic switch M2 to be turned off in the first preset time. In this way, the voltage output by the power supply unit 131 is continuously stored in the inductor L1, and then the control chip 24 controls the second electronic switch M2 to be turned on for a second preset time, and controls the first electronic switch M1 to be turned off for the second preset time.

In this way, the voltage of the inductor L1 is superimposed on the voltage of the power supply unit 131, and the voltage is output to the driving module 22 via the second electronic switch M2. That is, the inductor L1, the first electronic switch M1, and the second electronic switch M2 together function as a boost.

It will be appreciated that in the present embodiment, in the first case, the longer the first preset time, the shorter the second preset time. That is, as the voltage stored in the boosting unit 231 is larger, the discharge time is shorter, and the magnitude of the voltage output from the second terminal S2 of the second electronic switch M2 is larger. In the second case, the shorter the first preset time, the longer the second preset time. That is, as the voltage stored in the boosting unit 231 is smaller and the discharge time is longer, the magnitude of the voltage output from the second terminal S2 of the second electronic switch M2 is smaller.

The first sampling resistor R11 and the second sampling resistor R12 in the sampling unit 232 are used for sampling the voltage output by the second electronic switch M2 while the second electronic switch M2 outputs the voltage. It can be appreciated that the sampling voltage of the first input 2331 of the comparator COM is according to the circuit diagram shown in fig. 6

The voltage outputted by the reference voltage source REF is

Wherein VH is a preset amplitude of the second voltage signal.

Thus, when the voltage of the first input terminal 2331 is smaller than the voltage of the second input terminal 2332, that is, the voltage amplitude of the second voltage signal V2 output by the boosting unit 231 is smaller than the preset voltage amplitude, the comparator COM outputs the first signal to the control chip 24 through the output terminal 2333. After the control chip 24 receives the first signal, the first preset time is prolonged and/or the second preset time is shortened, so as to increase the voltage amplitude of the second voltage signal V2; when the voltage of the first input end 2331 is greater than the voltage of the second input end 2332, that is, the voltage amplitude of the second voltage signal V2 output by the boost unit 231 is greater than the preset voltage amplitude, the comparator COM outputs the second signal to the control chip 24 through the output end 2333, and after the control chip 24 receives the second signal, the first preset time is shortened and/or the second preset time is prolonged, so as to reduce the voltage amplitude of the second voltage signal V2. In this way, the sampling unit 232 and the comparing unit 233 can make the voltage amplitude of the second voltage signal V2 output by the boost module 23 reach the preset amplitude, and stably output the second voltage signal V2.

It is understood that the upper limits of the voltages output by the first amplifier OPA1 and the second amplifier OPA2 in the driving module 22 are determined by the magnitudes of the voltages received by the first power input terminal SOU1 and the second power input terminal SOU2, respectively. That is, when the boost module 23 outputs the second voltage signal V2 to the first power input terminal SOU1 and the second power input terminal SOU2, the voltage magnitudes of the first driving signal VD1 and the second driving signal VD2 respectively output by the first amplifier OPA1 and the second amplifier OPA2 in the driving module 22 are smaller than or equal to the voltage magnitude of the second voltage signal V2.

It is understood that in other embodiments, the boosting module 23 may be replaced by other circuits or chips for boosting the dc signal. The present application is not limited to the specific circuit of the BOOST module 23, for example, in other embodiments, the BOOST module 23 may be a BOOST circuit, a Charge Pump BOOST circuit, or a BOOST circuit including a single-ended primary inductor converter (Single Ended Primary Inductor Converter, SEPIC), etc.

It is understood that, in some embodiments, when the voltage output by the power supply unit 131 of the electronic device 100 meets the power requirement of the driving module 22, the driving circuit 20 may not provide the voltage boosting module 23.

It is understood that the driving circuit 20 provided by the present application can also be applied to a housing assembly provided with a smart glass including an electrically variable layer 152 or other housing assemblies having an electrically variable layer 152.

It can be appreciated that, in the electronic device 100 provided by the present application, the electrically-variable layer 152 is disposed on the rear cover 15, and the driving circuit 20 is used for driving the electrically-variable layer 152 to generate corresponding changes, so as to realize various changes of the rear cover 15 of the electronic device 100, which is beneficial to improving the overall aesthetic degree of the electronic device 100.

Further, the driving circuit 20 is configured with the driving module 22 to convert one voltage signal into the first driving signal VD1 and the second driving signal VD2 with opposite phases and equal amplitudes, so as to form an equivalent ac voltage signal at two ends of the electrically variable layer 152, thereby driving the electrically variable layer 152 to generate corresponding changes.

Compared with the prior art, the driving circuit 20 provided by the embodiment of the application has at least the following advantages:

(1) The circuit structure and the used devices are simple, and the cost can be effectively reduced.

(2) The portable device without the alternating current power supply can be conveniently used.

(3) The waveform of the driving signal can be flexibly adjusted, the voltage withstand value of key components is reduced, and the safety of the circuit is improved.

(4) The absence of a dc bias for the drive signal may allow for better variation of the electro-variable layer 152.

The above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present application.

Claims

1. The driving circuit is applied to electronic equipment powered by a direct-current power supply, and a shell of the electronic equipment comprises an electrically-variable layer which presents corresponding light transmittance or color based on an alternating-current voltage signal, and is characterized in that the driving circuit is electrically connected with a power management module of the electronic equipment and the electrically-variable layer, and the power management module generates a pulse width modulation signal based on the direct-current voltage signal output by the direct-current power supply;

the driving circuit comprises a signal modulation module and a driving module, wherein the signal modulation module is electrically connected with the power management module, and the driving module is electrically connected with the signal modulation module and the electrically-induced variable layer;

The signal modulation module is used for modulating the pulse width modulation signal to obtain a first voltage signal, and the first voltage signal meets the frequency requirement of the voltage for driving the electrically variable layer;

the driving module is used for amplifying the first voltage signal to obtain a first driving signal; amplifying and inverting the first voltage signal to obtain a second driving signal; the first driving signal and the second driving signal are equal in amplitude and opposite in phase; the first driving signal and the second driving signal are respectively output to two ends of the electric variable layer to form an equivalent alternating voltage signal for driving the electric variable layer.

2. The drive circuit of claim 1, wherein the peak-to-peak value of the first drive signal and the peak-to-peak value of the second drive signal are each half of the peak-to-peak value of the equivalent ac voltage signal.

3. The driving circuit according to claim 1 or 2, wherein the driving module comprises a first driving unit and a second driving unit, wherein the first driving unit is configured to amplify the first voltage signal to obtain the first driving signal, and the second driving unit is configured to amplify and invert the first voltage signal to obtain the second driving signal.

4. The drive circuit of claim 3, wherein the first drive unit comprises a first amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor;

the first amplifier comprises a first in-phase input end, a first out-phase input end and a first output end, one end of the first resistor is used for receiving the first voltage signal, and the other end of the first resistor is electrically connected to the first out-phase input end; one end of the second resistor is electrically connected between the first resistor and the first inverting input end, and the other end of the second resistor is electrically connected to the first output end; one end of the third resistor is electrically connected to the first in-phase input end, and the other end of the third resistor is electrically connected to the reference ground; one end of the fourth resistor is electrically connected between the third resistor and the first in-phase input end, and the other end of the fourth resistor is electrically connected to the reference ground; the first output end is used for outputting the first driving signal.

5. The driving circuit according to claim 3, wherein the second driving unit includes a second amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and an eighth resistor;

the second amplifier comprises a second non-inverting input end, a second inverting input end and a second output end, one end of the fifth resistor is electrically connected to the reference ground, and the other end of the fifth resistor is electrically connected to the second inverting input end; one end of the sixth resistor is electrically connected between the fifth resistor and the second inverting input end, and the other end of the sixth resistor is electrically connected to the second output end; one end of the seventh resistor is electrically connected to the second non-inverting input end, and the other end of the seventh resistor is used for receiving the first voltage signal; one end of the eighth resistor is electrically connected between the seventh resistor and the second non-inverting input end, and the other end of the eighth resistor is electrically connected to the reference ground; the second output end is used for outputting the second driving signal.

6. The driving circuit according to any one of claims 1 to 5, wherein the signal modulation module comprises a filtering module, and the filtering module is configured to filter out a high-frequency signal in the pulse width modulated signal, so as to obtain the first voltage signal.

7. The drive circuit according to any one of claims 1 to 6, further comprising a control chip electrically connected to the signal modulation module, the control chip for controlling a duty cycle of the pulse width modulated signal.

8. The drive circuit according to any one of claims 1 to 7, further comprising a boost module electrically connected to the drive module, the boost module configured to boost a dc voltage signal output by the dc power supply to obtain a second voltage signal, the second voltage signal being configured to power the drive module.

9. The drive circuit of claim 8, wherein the boost module comprises a boost unit, a sampling unit and a comparison unit, the boost unit is electrically connected with the dc power supply and the control chip, the sampling unit is electrically connected with the boost unit, and the comparison unit is electrically connected with the sampling unit and the control chip; wherein,

The boosting unit is used for boosting the direct-current voltage signal output by the direct-current power supply to obtain a second voltage signal;

the sampling unit is used for sampling the second voltage signal to obtain a sampling voltage;

the comparison unit is used for comparing the sampling voltage with a reference voltage to obtain a comparison result;

the control chip is used for controlling the magnitude of the second voltage signal output by the boosting unit according to the comparison result so as to stabilize the second voltage signal.

10. The drive circuit according to claim 9, wherein: the boost unit comprises an inductor, a first electronic switch and a second electronic switch, one end of the inductor is electrically connected to the power supply unit, the other end of the inductor is electrically connected to the first end of the first electronic switch and the first end of the second electronic switch, the second end of the first electronic switch is electrically connected to the reference ground, the third end of the first electronic switch is electrically connected to the control chip, the third end of the second electronic switch is electrically connected to the control chip, the second end of the second electronic switch is electrically connected to the driving module, the control chip controls the first electronic switch to be conducted within a first preset time and the second electronic switch to be disconnected within the first preset time, so that the inductor stores the voltage output by the power supply unit, and the control chip also continues to control the second electronic switch to be turned on within a second preset time and controls the first electronic switch to be turned off within the second preset time, so that the inductor outputs a second voltage signal to the driving module via the second electronic switch.

11. The drive circuit according to claim 10, wherein: the sampling unit comprises a first sampling resistor and a second sampling resistor, one end of the first sampling resistor is electrically connected to the second end of the second electronic switch, the other end of the first sampling resistor is electrically connected to one end of the second sampling resistor, and the other end of the second sampling resistor is electrically connected to the reference ground;

the comparison unit comprises a comparator and a reference voltage source, wherein the comparator comprises a first input end, a second input end and an output end, the first input end is an inverted input end, the second input end is a non-inverting input end, the first input end is electrically connected between the first sampling resistor and the second sampling resistor, the second input end is electrically connected to the positive electrode of the reference voltage source, the negative electrode of the reference voltage source is electrically connected to the reference ground, and the output end is electrically connected to the control chip;

and the control chip controls the duty ratio of the first electronic switch and the second electronic switch according to the comparison result so as to adjust the voltage amplitude of the second voltage signal output by the boosting module.

12. The drive circuit according to claim 11, wherein: the sampling unit further comprises a sampling capacitor, one end of the sampling capacitor is electrically connected between the second end of the second electronic switch and the first sampling resistor, and the other end of the sampling capacitor is electrically connected to the reference ground.

13. A housing assembly for an electronic device powered by a dc power source, the housing assembly comprising a housing comprising an electrically variable layer that exhibits a corresponding light transmittance or color based on an ac voltage signal, characterized in that the housing assembly further comprises a drive circuit according to any one of claims 1-12 electrically connected to both ends of the electrically variable layer for outputting the first and second drive signals to both ends of the electrically variable layer.

14. An electronic device comprising a direct current power supply and a housing, the housing comprising an electrically variable layer exhibiting a corresponding light transmittance or color based on an alternating voltage signal, characterized in that the electronic device further comprises a driving circuit according to any one of claims 1-12, the driving circuit being electrically connected to both ends of the electrically variable layer for outputting the first driving signal and the second driving signal to both ends of the electrically variable layer.