WO2018121707A1

WO2018121707A1 - Device for controlling brightness of mobile phone screen

Info

Publication number: WO2018121707A1
Application number: PCT/CN2017/119671
Authority: WO
Inventors: 罗伟
Original assignee: 广州兴普电子科技有限公司
Priority date: 2016-12-30
Filing date: 2017-12-29
Publication date: 2018-07-05

Abstract

A device for controlling the brightness of a mobile phone screen, comprising a mobile phone screen light source module, a rectifying processing module, a triac dimmer, a first constant current controller, a second constant current controller, an electrolytic capacitor, a first rectifier diode, a second rectifier diode, a first sampling resistor, and a second sampling resistor. Because the first constant current controller can be turned on to provide an anode forward current needed for keeping the triac dimmer turned on; moreover, a high power factor value is provided, adjustment can easily be implemented, a circuit is simple in structure, and low costs are needed. In addition, when the rectified bus voltage is less than the turn-on voltage drop of the mobile phone screen light source, the electrolytic capacitor supplies electricity to the mobile phone screen light source, so that a mobile phone screen light source lamp string continues in an operating state when the rectified bus voltage is less than the turn-on voltage drop of the mobile phone screen light source; moreover, by removing stroboscopic components of the mobile screen light source, the stroboscopic phenomenon can be prevented, and an operating input voltage range is widened.

Description

Mobile phone screen brightness control device

Technical field

The present invention relates to the field of mobile phone screen technology, and more particularly to a mobile phone screen brightness control device.

Background technique

With the advent of smart phones, mobile phone screens have become the most important component of mobile phones. Generally, in different environments, screen brightness needs to be adjusted according to specific conditions. For example, in a dim environment, the brightness of the mobile phone screen needs to be increased. Or in the strong light, increase the brightness of the mobile phone for the user to view, but in the prior art, the brightness of the screen of the mobile phone is adjusted to cause flicker, and the long-term use is unfavorable to the user's health. How to conveniently adjust the brightness of the screen of the mobile phone is a problem faced by the industry.

Summary of the invention

In view of the above problems, embodiments of the present invention provide a mobile phone screen brightness control device that partially or completely solves the above problems, to avoid the problem of screen flicker in a switch switching state, and the implementation circuit has a high power factor, and the circuit structure is simple and easy. The adjustment is achieved at a lower cost.

In order to solve the above technical problem, the present application adopts the following technical solutions:

A mobile phone screen brightness control device according to an embodiment of the present invention includes a mobile phone screen display processing unit, and further includes a mobile phone screen brightness control unit connected to the mobile phone screen display processing unit, and the mobile phone screen brightness control unit is specifically include:

Light source module, rectification processing module, thyristor dimmer, first constant current controller, second constant current controller, electrolytic capacitor, first rectifier diode, second rectifier diode, first sampling resistor, second sampling resistor ;

The rectification processing module is connected to an external power supply through the thyristor, and a normal phase output end of the rectification processing module is connected to one end of the first constant current controller and an anode of the first rectifying diode. The negative phase output end of the rectification processing module is connected to the other end of the first constant current controller and grounded, and the control terminal A of the first constant current controller passes the first sampling resistor and the second sampling a resistor is grounded, the first sampling resistor and the second sampling resistor are connected by a point C, a cathode of the first rectifier diode is connected to an anode of the light source module and a cathode of the electrolytic capacitor, and a cathode of the electrolytic capacitor Connecting one end of the second constant current controller and a cathode of the second rectifier diode, the other end of the second constant current controller and the anode of the second rectifier diode are grounded, the second constant current The control terminal D of the controller is grounded through the second sampling resistor;

Wherein when the voltage at the control terminal A of the first constant current controller is greater than the voltage at point C, the first constant current controller is turned on to provide an anode forward required to maintain conduction of the thyristor dimmer Current; the electrolytic capacitor supplies power to the light source when the rectified bus voltage is less than the conduction voltage drop of the light source module.

The light source module specifically includes:

a light string, a third constant current controller, and a third sampling resistor, wherein an anode of the string is connected to a cathode of the first rectifier diode and an anode of the electrolytic capacitor, a cathode of the string and the first One end of the three constant current controller is connected, and the other end of the third constant current controller is grounded, and the control terminal B of the third constant current controller is grounded through the third sampling resistor.

Wherein, the rectification processing module is a rectifier bridge stack.

In addition, it also includes an input control switch connected to an external power supply.

Correspondingly, the present invention further provides a mobile phone screen brightness control device, including:

a light source module for providing a screen light source of the mobile phone;

a thyristor dimmer for controlling the input current of the external power source to adjust the brightness of the light source;

The rectification processing module is connected to the external power source through the thyristor dimmer, and is used for rectifying the input external power source;

a first constant current controller processing module coupled to the rectification processing module for providing an anode forward current required to maintain conduction of the thyristor dimmer;

The electrolytic capacitor processing module is connected to the light source module, and is configured to supply power to the light source when the rectified bus voltage is less than the light source voltage drop of the light source module;

The second constant current controller processing module is connected to the electrolytic capacitor processing module for controlling charging and discharging of the electrolytic capacitor processing module.

The electrolytic capacitor processing module specifically includes:

An electrolytic capacitor, a first rectifier diode and a second rectifier diode, wherein the anode of the first rectifier diode is connected to a positive phase output end of the rectification processing module, a cathode thereof and an anode of the light source module and a positive electrode of the electrolytic capacitor Connected, the cathode of the electrolytic capacitor is connected to the second constant current controller processing module and the cathode of the second rectifier diode, and the anode of the second rectifier diode is grounded.

The first constant current controller processing module specifically includes: a first constant current controller and a first sampling resistor;

The second constant current controller processing module specifically includes: a second constant current controller and a second sampling resistor;

The first constant current controller has one end connected to the positive phase output end of the rectification processing module and the other end grounded, and the control end A of the first constant current controller passes the first sampling resistor and the The second sampling resistor is grounded, and the first sampling resistor and the second sampling resistor are connected by a point C. The second constant current controller has one end connected to the negative pole of the electrolytic capacitor and the other end grounded, and the second The constant current controller control terminal D is grounded through the second sampling resistor.

The light source module specifically includes:

a light string, a third constant current controller, and a third sampling resistor, wherein a cathode of the string is connected to one end of the third constant current controller, and the other end of the third constant current controller is grounded, The control terminal B of the third constant current controller is grounded through the third sampling resistor.

Wherein, the rectification processing module is a rectifier bridge stack.

A screen brightness control device for a mobile phone according to an embodiment of the invention includes a light source module for providing a screen light source of the mobile phone; and a thyristor dimmer for controlling the input current of the external power source to adjust the brightness of the screen light source of the mobile phone; The rectification processing module is connected to the external power supply through the thyristor dimmer for rectifying the input external power supply; the first constant current controller processing module is connected to the rectification processing module for providing the maintenance The anode forward current required for conducting the thyristor dimmer; the electrolytic capacitor processing module is connected to the light source module, and configured to: when the rectified bus voltage is less than the light source voltage drop of the light source module, The mobile phone screen light source is powered; the second constant current controller processing module is connected to the electrolytic capacitor processing module for controlling charging and discharging of the electrolytic capacitor in the electrolytic capacitor processing module, because the first constant current controller can process the module Providing an anode forward current required to maintain conduction of the thyristor dimmer, enabling the thyristor dimmer to be activated during the next cycle It can be quickly started, avoiding the problem of flickering of the screen light of the mobile phone during the switching state of the switch, and the rapid power-on of the thyristor dimmer improves the active power of the circuit, that is, the realization circuit has a high power factor value, and is easy to adjust. And the circuit structure is simple and the cost is low;

In addition, the electrolytic capacitor processing module eliminates the stroboscopic component in the screen light source of the mobile phone, can avoid the stroboscopic phenomenon, and widens the working input voltage range, so that the bus voltage of the mobile phone screen light source after rectification is smaller than the mobile phone screen light source. When the conduction voltage drop of the middle light string continues to maintain the working state, and when the electrolytic capacitor processing module supplies power to the light string of the mobile phone screen light source, the second constant current controller processing module can make the electrolytic capacitor give the light string of the screen light source of the mobile phone The power supply is extended to further increase the light efficiency.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a few embodiments described in the present invention, and other drawings can be obtained from those skilled in the art from the drawings.

1 is a waveform diagram of a bus voltage of a rectified electrolytic capacitor with a screen brightness control device of a mobile phone according to the present invention;

2 is a schematic diagram showing the circuit structure of a specific embodiment of a screen brightness control device for a mobile phone according to the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention are within the scope of the present invention.

In the prior art, the screen brightness control device of the mobile phone has a problem of flickering on the screen of the mobile phone in the state of switching the switch, and also reduces the power factor (PF) value of the circuit. In the specific implementation, the prior art mobile phone screen brightness control device The LC filter at the input causes the thyristor to oscillate. This oscillation produces audible noise and flicker for the driving power of the LED or the like.

The core of the invention is that the screen brightness control device of the mobile phone provides the screen light source of the mobile phone through the light source module; the input current of the external power source is controlled by the thyristor dimmer to adjust the brightness of the screen light source of the mobile phone; and the input external power source is rectified by the rectification processing module. Providing an anode forward current required to maintain conduction of the thyristor dimmer through the first constant current controller processing module; the bus voltage after rectification by the electrolytic capacitor processing module is less than the light source conduction voltage drop of the light source module And supplying power to the mobile phone screen light source; and controlling charging and discharging of the electrolytic capacitor processing module by the second constant current controller processing module.

It should be noted that, as a specific embodiment, the electrolytic capacitor processing module may specifically include: an electrolytic capacitor, a first rectifier diode, and a second rectifier diode, wherein the anode of the first rectifier diode is connected to the positive phase of the rectifier processing module The output terminal has a cathode connected to the anode of the electrolytic capacitor and an anode of the string, and a cathode of the first rectifier diode is connected to the second constant current controller processing module.

In addition, as a specific embodiment, the first constant current controller processing module may specifically include: a first constant current controller and a first sampling resistor; and the second constant current controller processing module may specifically include: a constant current controller and a second sampling resistor; wherein the first constant current controller has one end connected to the positive phase output end of the rectification processing module and the other end grounded, and the control end A of the first constant current controller The first sampling resistor and the second sampling resistor are grounded, the first sampling resistor and the second sampling resistor are connected by a point C, and the second constant current controller is connected to the electrolytic capacitor at one end thereof. The other end is grounded, and the control terminal D of the second constant current controller is grounded through the second sampling resistor.

In addition, as a specific embodiment, the light source module may specifically include: a light string, a third constant current controller, and a third sampling resistor, wherein a cathode of the light string is connected to one end of the third constant current controller, The other end of the third constant current controller is grounded, and the control terminal B of the third constant current controller is grounded through a third sampling resistor.

In summary, according to the mobile phone screen brightness control device of the embodiment, the first constant current controller processing module provides an anode forward current required to maintain the conduction of the thyristor dimmer, and the thyristor can be dimmed. When the next cycle starts, it can be started quickly, avoiding the problem of flashing the screen of the mobile phone when the switch is switched, and the active power of the circuit is improved because the thyristor dimmer is quickly turned on, that is, the circuit is high. The power factor value is easy to adjust, and the circuit structure is simple and the cost is low;

In addition, the electrolytic capacitor of the electrolytic capacitor processing module eliminates the stroboscopic component passing through the screen light source of the mobile phone, thereby avoiding the stroboscopic phenomenon and widening the working input voltage range, so that the bus voltage of the mobile phone screen light source after rectification is smaller than that of the mobile phone screen light source. When the voltage drop is turned on, the working state is continued. In addition, when the electrolytic capacitor processing module supplies power to the screen light source of the mobile phone, the processing time of the electrolytic capacitor to the screen light source of the mobile phone is extended by the second constant current controller processing module, thereby further increasing. Light efficiency.

The following is a specific example.

Referring to Fig. 1, there is shown a diagram of a bus voltage waveform of an electrolytic capacitor after rectification in a mobile phone screen brightness control device according to the present invention.

As shown in the figure, the rectified bus voltage waveform in this embodiment is a non-sinusoidal wave. Specifically, in this embodiment, the thyristor dimmer is turned on at time t1, turned off at time t2, and is turned off at another time. At time t3, the thyristor dimmer is re-conducted, and the cycle is continued. In the range of t2 and t3, the light source of the mobile phone screen can be powered by the electrolytic capacitor, that is, within the interval of t2 and t3, the screen of the mobile phone The light source can be kept lit, and will not be described here.

This embodiment is applicable to a linear single-segment stroboscopic method for dimming. In specific implementation, the thyristor dimmer is used to control the screen light source of the mobile phone, for example, controlling the screen light source of the mobile phone to be the brightness of the LED lamp load, as a specific embodiment. The rectification processing module can adopt the rectifier bridge stack BR1. In addition, in order to facilitate the input power control, the power switch can be further included. Specifically, the screen light source of the mobile phone is taken as an example for the LED light, and the screen brightness control device of the mobile phone in this embodiment is mainly include:

Power switch S0, thyristor dimmer BG1, rectifier bridge stack BR1, rectifier diode VD1 (ie, first rectifier diode), rectifier diode VD2 (ie, second rectifier diode); electrolytic capacitor C1, 3 LED constant current controller , namely: LED constant current controller 1 (ie, the first LED constant current controller), LED constant current controller 2 (ie, the second LED constant current controller), LED constant current controller 3 (ie, the third LED constant current) Controller), sampling resistors R1, R2, R3 (ie, first sampling resistor, second sampling resistor, third sampling resistor) and LED light string as a light source of the mobile phone screen (in practice, the LED light string may include, for example, three LED lights The bead may also be other numbers of LED lamp beads, which are not specifically limited herein. In this embodiment, the LED constant current controller 1 and the sampling resistor R1 constitute a first LED constant current controller processing module, and the LED constant current controller 2 And the sampling resistor R2 constitutes a second LED constant current controller processing module, the LED light string, the LED constant current controller 3 and the sampling resistor R3 constitute an LED light source module, and the electrolytic capacitor C1, the rectifier diode VD1 and the rectifier diode VD2 constitute an electrolysis Capacitor processing module, the connection relationship of each component in the specific circuit, such as under:

The rectifier bridge stack BR1 is connected to the external power supply through the power switch S0 and the thyristor dimmer BG1. The positive phase output of the rectifier bridge stack BR1 is connected to one end of the LED constant current controller 1 and the anode of the rectifier diode VD1, and the rectifier bridge stack BR1 The negative phase output terminal is connected to the other end of the LED constant current controller 1 and grounded. The control terminal A of the LED constant current controller 1 is grounded through the sampling resistors R1 and R2, and the sampling resistors R1 and R2 are connected by the C point; the rectifier diode VD1 The cathode is connected to the anode of the LED string, while the cathode of the rectifier diode VD1 is connected to the anode of the electrolytic capacitor C1; the cathode of the electrolytic capacitor C1 is connected to one end of the LED constant current controller 2, and the cathode of the electrolytic capacitor C1 is connected to the cathode of the rectifier diode VD2; The control terminal D of the LED constant current controller 2 is grounded through a sampling resistor R2, wherein point D is connected to point C; and the anode of the rectifier diode VD2 is grounded, and the cathode of the LED string is connected to one end of the LED constant current controller 3 The other end of the LED constant current controller 3 is grounded, and the control terminal B end of the LED constant current controller 3 is grounded through the sampling resistor R3.

The working process of the screen brightness control device of the mobile phone of this embodiment is described in detail below:

When the power switch is closed, during the T1 cycle, the thyristor dimmer BG1 triggers conduction at time t1 to adjust the thyristor dimmer BG1, and the rectified bus voltage Vin continues to rise, and the LED constant current controller 1 detects and controls Terminal A voltage, when the voltage at point A is less than the voltage at point C, the LED constant current controller 1 is turned off, in addition, the LED constant current controller 2 is turned on so that the electrolytic capacitor C1 can be charged through the bus, with the bus voltage Vin Rising, when the bus voltage Vin>V _{LED string} (ie, the bus voltage is greater than the conduction voltage drop of the LED string), the LED constant current controller 3 provides constant current driving as the LED string, and the LED string lights up, and continues to adjust. The thyristor dimmer BG1, the LED string gradually becomes brighter, continuously adjusts the thyristor dimmer, and the brightness of the LED string increases accordingly. During this period, the electrolytic capacitor C1 continues to charge; during the T1 period, when the bus voltage When the maximum is reached, the brightness of the LED string is also maximized. At this time, the power of the electrolytic capacitor C1 is also maximized; the LED constant current controller 3 drives the LED string to control the current of the LED string, and the current flowing through the LED string. For: I _LED _string = Vth / R3;

It should be noted that during the T1 period, the thyristor dimmer BG1 is adjusted. When the bus voltage Vin starts to decrease slowly, the brightness of the LED string is correspondingly reduced, when the bus voltage Vin<V _{LED string} ( That is, the bus voltage is less than the conduction voltage drop of the LED string, and the LED electrolytic capacitor C1 continuously supplies the required current to the LED string until the next cycle bus voltage Vin>V _{LED string} ;

In addition, during the T1 period, when the bus voltage Vin continues to decrease, the LED constant current controller 1 detects the voltage at the control terminal A. When the voltage at the point A is greater than the voltage at the C point, the LED constant current controller 1 is turned on, at time t2. The thyristor dimmer BG1 triggers the shutdown, and the LED constant current controller 1 can provide the anode forward current necessary for maintaining the conduction of the thyristor dimmer BG1;

In the T2 cycle, the thyristor dimmer BG1 triggers conduction again at time t3 to adjust the thyristor dimmer BG1. As the bus voltage Vin rises, the electrolytic capacitor C1 is charged through the bus, and the LED constant current The controller 1 detects the voltage at the control terminal A. When the voltage at the point A is less than the voltage at the point C, the LED constant current controller 1 is turned off, and the thyristor dimmer BG1 is continuously adjusted, when the bus voltage Vin>V _{LED string} is ( That is, the bus voltage is greater than the conduction voltage drop of the LED string, and the LED string 1 is lit. At this time, the LED string is powered by the power supply, and the subsequent control process repeats the above control process, which will not be described here.

In summary, according to the mobile phone screen brightness control device of the embodiment, the LED constant current controller processing module 1 provides an anode forward current required to maintain the conduction of the thyristor dimmer, and the thyristor can be dimmed. When BG1 is started in the next cycle, it can be started quickly, avoiding the problem that the screen light source of the mobile phone, that is, the LED lamp, flashes when the switch is switched, and the active power of the circuit is improved because the thyristor dimmer BG1 is turned on quickly. That is to say, the realization circuit has a high power factor value, which is easy to implement adjustment, and the circuit structure is simple and the required cost is low;

In addition, in the circuit of the embodiment, the stroboscopic component of the LED light string passing through the screen light source of the mobile phone is eliminated by the electrolytic capacitor C1, the stroboscopic phenomenon can be avoided, and the working input voltage range is widened, so that the LED light string is after the rectified bus bar. When the voltage is lower than the conduction voltage drop of the LED string, the operation state is continued. In addition, when the electrolytic capacitor C1 supplies power to the LED string in the circuit of the embodiment, the electrolytic capacitor C1 can be given to the LED lamp through the LED constant current controller 2. The length of the string power supply is extended, and the light effect intensity is further increased. In addition, the rectifying diode VD2 is freewheeled in the circuit of the embodiment, so that the circuit loss is greatly reduced and the efficiency is improved during the power supply of the electrolytic capacitor C1 to the LED string.

The technical solutions provided by the embodiments of the present invention are described in detail above. The principles and implementation manners of the embodiments of the present invention are described in the following. The description of the foregoing embodiments is only applicable to help understand the embodiments of the present invention. At the same time, there will be changes in the specific embodiments and application scopes according to the embodiments of the present invention, and it should be noted that the above embodiments illustrate the present invention rather than the present invention. Limitations, and alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims.

Claims

A mobile phone screen brightness control unit, comprising: a mobile phone screen display processing unit, further comprising: a mobile phone screen brightness control unit connected to the mobile phone screen display processing unit, the mobile phone screen brightness control unit specifically comprising:

Light source module, rectification processing module, thyristor dimmer, first constant current controller, second constant current controller, electrolytic capacitor, first rectifier diode, second rectifier diode, first sampling resistor, second sampling resistor ;

The rectification processing module is connected to an external power supply through the thyristor, and a normal phase output end of the rectification processing module is connected to one end of the first constant current controller and an anode of the first rectifying diode. The negative phase output end of the rectification processing module is connected to the other end of the first constant current controller and grounded, and the control terminal A of the first constant current controller passes the first sampling resistor and the second sampling a resistor is grounded, the first sampling resistor and the second sampling resistor are connected by a point C, a cathode of the first rectifier diode is connected to an anode of the light source module and a cathode of the electrolytic capacitor, and a cathode of the electrolytic capacitor Connecting one end of the second constant current controller and a cathode of the second rectifier diode, the other end of the second constant current controller and the anode of the second rectifier diode are grounded, the second constant current The control terminal D of the controller is grounded through the second sampling resistor;

Wherein when the voltage at the control terminal A of the first constant current controller is greater than the voltage at point C, the first constant current controller is turned on to provide an anode forward required to maintain conduction of the thyristor dimmer Current; the electrolytic capacitor supplies power to the light source when the rectified bus voltage is less than the conduction voltage drop of the light source module.
The circuit of claim 1 , wherein the light source module comprises:

a light string, a third constant current controller, and a third sampling resistor, wherein an anode of the string is connected to a cathode of the first rectifier diode and an anode of the electrolytic capacitor, a cathode of the string and the first One end of the three constant current controller is connected, and the other end of the third constant current controller is grounded, and the control terminal B of the third constant current controller is grounded through the third sampling resistor.
The apparatus of claim 1 wherein said rectification processing module is a rectifier bridge stack.
A device according to any one of claims 1 to 3, further comprising an input control switch connected to an external power source.
A mobile phone screen brightness control device, comprising:

a light source module for providing a screen light source of the mobile phone;

a thyristor dimmer for controlling the input current of the external power source to adjust the brightness of the screen light source of the mobile phone;

The rectification processing module is connected to the external power source through the thyristor dimmer, and is used for rectifying the input external power source;

a first constant current controller processing module coupled to the rectification processing module for providing an anode forward current required to maintain conduction of the thyristor dimmer;

The electrolytic capacitor processing module is connected to the light source module, and is configured to supply power to the light source when the rectified bus voltage is less than the light source voltage drop of the light source module;

The second constant current controller processing module is connected to the electrolytic capacitor processing module for controlling charging and discharging of the electrolytic capacitor processing module.
The device according to claim 5, wherein the electrolytic capacitor processing module specifically comprises:

An electrolytic capacitor, a first rectifier diode and a second rectifier diode, wherein the anode of the first rectifier diode is connected to a positive phase output end of the rectification processing module, a cathode thereof and an anode of the light source module and a positive electrode of the electrolytic capacitor Connected, the cathode of the electrolytic capacitor is connected to the second constant current controller processing module and the cathode of the second rectifier diode, and the anode of the second rectifier diode is grounded.
The apparatus according to claim 6, wherein the first constant current controller processing module comprises: a first constant current controller and a first sampling resistor;

The second constant current controller processing module specifically includes: a second constant current controller and a second sampling resistor;

The first constant current controller has one end connected to the positive phase output end of the rectification processing module and the other end grounded, and the control end A of the first constant current controller passes the first sampling resistor and the The second sampling resistor is grounded, and the first sampling resistor and the second sampling resistor are connected by a point C. The second constant current controller has one end connected to the negative pole of the electrolytic capacitor and the other end grounded, and the second The constant current controller control terminal D is grounded through the second sampling resistor.
The device according to claim 6, wherein the light source module specifically comprises:

a light string, a third constant current controller, and a third sampling resistor, wherein a cathode of the string is connected to one end of the third constant current controller, and the other end of the third constant current controller is grounded, The control terminal B of the third constant current controller is grounded through the third sampling resistor.
Apparatus according to any of claims 5-8, wherein said rectification processing module is a rectifier bridge stack.
The apparatus of claim 5 further comprising an input control switch coupled to the external power source.