CN113035135A - Numerical control backlight adjusting circuit and method based on vehicle running state - Google Patents

Abstract

The invention discloses a numerical control adjusting backlight circuit and method based on a vehicle running state, wherein the numerical control adjusting backlight circuit comprises five light intensity acquisition circuits, a level matching network U2, a processor chip U3, a multi-path backlight control chip U4, a triode switch circuit, a reversing detection module U6 and the like. The circuit provided by the invention has the advantages of simple structure, easiness in realization, low cost and strong universality, can be applied to the vehicle-mounted display screen and is used for realizing backlight self-adaptive digital regulation control under different driving states, so that backlight of the vehicle-mounted display screen can be displayed in a self-adaptive manner under different environments, and stronger comfort is brought to people.

Description

Numerical control backlight adjusting circuit and method based on vehicle running state

Technical Field

The invention relates to the field of vehicle-mounted equipment, in particular to a numerical control backlight adjusting circuit and method based on a vehicle running state.

Background

With the rapid development of the automobile market, the application of the vehicle-mounted display screen in the automobile field is more and more extensive. In the in-service use, the customer also constantly improves to the display effect requirement in a poor light of on-vehicle display screen, and the change that actually requires the display screen can be according to external environment changes in a poor light, and when external light was strong, the accent of certain degree is shaded to the display screen, and when external light weakened, the dim of certain degree is shaded to the display screen to can not influence driver safe driving, improve the comfort that the light irradiation brought in the car. The general design method is that the light sensor is assembled on the display screen to collect the change of the light intensity in the vehicle; or by GPS positioning function, time difference between day and night and position analysis are carried out to judge the change of light intensity. The two methods can obtain the change of the external light intensity, and simultaneously are matched with corresponding CPU control to realize the self-adaptive adjustment and control of the backlight. The former method mainly aims at the collection and judgment of the light intensity of the environment inside the vehicle and cannot adapt to the change of the environment outside the vehicle, and the latter method mainly aims at the positioning analysis of the space position outside the vehicle, after all, the GPS has certain error, and cannot ensure that the GPS signal is strong enough (such as a long-distance tunnel and the like) under various environments, and once the GPS signal is not good, the related data is lost. In addition, during the vehicle-mounted driving process, the light intensity at each position outside the vehicle is possibly inconsistent, for example, when the vehicle moves forward, the light intensity at the left front part and the light intensity at the right front part outside the vehicle are inconsistent (for example, when the vehicle drives at night, a street lamp is arranged at one side, and no street lamp is arranged at the other side); when the vehicle backs, the light intensity of the left rear part and the right rear part outside the vehicle is inconsistent. Furthermore, the light intensity inside the vehicle is not consistent with the light intensity outside the vehicle due to the influence of the window glass, the certain reflection of the glass to the light intensity, and the like. Therefore, the collection of the light intensity is carried out only inside or outside the vehicle, the error is obviously large, the real-time light intensity change cannot be accurately reflected, the corresponding adjustment backlight is removed at the moment, the inevitable error is large, the backlight is too small or excessively adjusted, and therefore the comfort brought by the backlight of the display screen is reduced. In view of these problems, a circuit and a method for digitally adjusting a backlight based on a driving state of a vehicle are needed.

Disclosure of Invention

The invention aims to provide a numerical control adjusting backlight circuit and method based on a vehicle running state, so as to solve the problems. Therefore, the invention adopts the following specific technical scheme:

according to an aspect of the invention, a numerical control adjusting backlight circuit based on a vehicle driving state is provided, wherein the numerical control adjusting backlight circuit comprises a processor chip U3 and a five-way light intensity acquisition circuit, U3 has at least 5 IO ports, I/O1 is configured as an input port for detecting the vehicle driving state, I/O2, I/O3 and I/O4 are output ports and are respectively electrically connected with an address signal port A, B, C of a multi-channel ADC chip U1 of the five-way light intensity acquisition circuit, and I/O5 is a PWM output port and is connected with a multi-way backlight control chip U4; the five light intensity acquisition circuits are used for acquiring the light intensity of the left side and the right side in front of or behind the vehicle and the light intensity in the vehicle according to the signal A, B, C, converting the light intensity into digital quantity and sending the digital quantity to the U3, wherein the digital quantity output range is between 0 and 255; the U3 is used for carrying out average calculation on the received light intensity of the left and right sides in front or the left and right sides in back and the light intensity in the automobile, dividing the obtained average value DOUT by 255, and simultaneously controlling the I/O5 to output a PWM signal with the duty ratio of DOUT/255 and the frequency F, wherein the frequency F is the PWM frequency of the multi-path back light control chip U4.

Further, the five light intensity acquisition circuits comprise photoresistors R _ FL, R _ FR, R _ RL, R _ RR and RB, a multi-channel ADC chip U1 and voltage-dividing current-limiting resistors R1, R2, R3, R4 and R5, wherein the R _ FR, R _ FL, R _ RL, R _ RR and RB are respectively connected IN series with R1, R2, R3, R4 and R5 and connected between VCC and GND, and analog input channels IN0-IN4 of the multi-channel ADC chip U1 are respectively connected between the R _ FR, R _ FL, R _ RL, R _ RR and RB and between the R1, R2, R3, R4 and R5.

Further, the five-path light intensity acquisition circuit further comprises a level matching network U2, and the U2 is used for matching the level of the digital quantity output of the multi-channel ADC chip U1 and the level of the digital quantity input of the processor chip.

Further, U2 is a level translation IC or a voltage dividing resistor network.

Further, the I/O2, the I/O3, the I/O4 and the I/O A, B, C are respectively connected through corresponding triode switch circuits.

Further, the multi-channel ADC chip U1 is an 8-bit successive approximation ADC chip.

Further, I/O1 is used to receive reverse signals.

Further, the five-path light intensity acquisition circuit further comprises a reversing detection module U6, wherein IN represents reversing signal input, OUT represents reversing detection signals processed by U6, low represents reversing signals, high represents no reversing signals, and OUT is connected with the I/O1.

Further, the reverse detection module U6 is a detection circuit composed of a photoelectric coupler or a detection circuit composed of a triode.

According to another aspect of the present invention, there is provided a numerical control backlight adjusting method based on a vehicle driving state, wherein the method comprises the steps of:

providing a digitally controlled dimming backlight circuit as described above;

every preset time, the U3 judges the driving state of the vehicle by detecting I/O1, if the vehicle is judged to be in a reverse state, the U1 sequentially collects the light intensity of the left side and the right side behind the vehicle and in the vehicle and converts the light intensity into digital quantities D2, D3 and D4 by arranging I/O2, I/O3 and I/O4, the U3 reads D2, D3 and D4 and stores the digital quantities into an internal memory, and the U3 calculates the average value DOUT of the three data, wherein the DOUT is (D2+ D3+ D4)/3; if the vehicle is judged to be in a traveling state, the I/O2, the I/O3 and the I/O4 are arranged, so that the U1 sequentially collects the light intensity of the left side and the right side in front of the vehicle and the light intensity in the vehicle and converts the light intensity into digital quantities D0, D1 and D4, the U3 reads the digital quantities D0, D1 and D4 and stores the digital quantities into an internal memory of the U3, and the U3 calculates the average value DOUT of the three data, namely (D0+ D1+ D4)/3;

u3 controls I/O5 to output a PWM signal with a duty cycle of DOUT/255 and a frequency of F.

By adopting the technical scheme, the invention has the beneficial effects that: the circuit provided by the invention has the advantages of simple structure, easiness in realization, low cost and strong universality, can be applied to the vehicle-mounted display screen and is used for realizing backlight self-adaptive digital regulation control under different driving states, so that backlight of the vehicle-mounted display screen can be displayed in a self-adaptive manner under different environments, and stronger comfort is brought to people.

Drawings

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

FIG. 1 is a circuit schematic of the present invention;

fig. 2 is a schematic view of the installation position of the photo resistor.

Detailed Description

The invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1, a numerical control adjusting backlight circuit based on a vehicle driving state includes a five-way light intensity acquisition circuit, a level matching network U2, a processor Chip (CPU) U3, a multi-way backlight control chip U4, a triode switch circuit, a reverse detection module U6, and the like.

The five-path light intensity acquisition circuit can comprise photoresistors R _ FL, R _ FR, R _ RL, R _ RR and RB, a multi-channel ADC chip U1 and voltage-dividing current-limiting resistors R1, R2, R3, R4 and R5. U1 is an 8-bit successive approximation ADC chip, which is composed of an 8-channel analog switch, an address latch decoder, an AD converter and a tristate output latch. The correspondence between the address signal port A, B, C of the address latch decoder and the selected analog channels IN0, IN1, IN2, IN3, IN4 is shown IN Table one of FIG. 1. U1 uses five analog inputs (IN0, IN1, IN2, IN3, IN4) respectively connected between the photoresistors R _ FL, R _ FR, R _ RL, R _ RR and RB and the voltage-dividing current-limiting resistors R1, R2, R3, R4 and R5, namely used for measuring the divided voltage of the photoresistors R _ FL, R _ FR, R _ RL, R _ RR and RB; the 8-bit data output (OUT1, OUT2, OUT3, OUT4, OUT5, OUT6, OUT7, OUT8) has a digital output range of 0< DOUT < 255. In practice, for example, ADC0808, ADC0809, etc. may be selected. R _ FR is a photosensitive resistor arranged in front of and at the right of the vehicle head in actual application; r _ FL is a photoresistor arranged at the front left of the vehicle head in actual application; the R _ RL photoresistor at the rear left of the vehicle tail is arranged at the rear left of the vehicle tail in actual application; the photoresistor at the right side behind the R _ RR vehicle tail is arranged at the right side behind the vehicle tail in actual application; RB is a photoresistor in the vehicle, and is installed on a display screen in the vehicle in practical application. The corresponding positions of the respective photo resistors mounted on the vehicle are shown in fig. 2. The sensitive resistor is a resistor which is made by utilizing the photoelectric effect of a semiconductor and has the resistance value changed along with the intensity of incident light, namely, the resistance is reduced when the intensity of the incident light is high; if the incident light is weak, the resistance increases.

In practical applications, the U2 may select a level shift IC or a voltage dividing resistor network to match the U1 and the U3 levels, because the voltage of the U1 is higher than the voltage of the U3 to improve the interference capability. It should be understood that in some instances, U2 may also be omitted.

The U3 internally comprises a CPU, a DDR3, an EMMC, a PMIC and the like, has audio and video coding and decoding functions, comprises a dual-path LVDS interface, an HDMI interface, an MIPI _ CSI interface and a combined circuit comprising WIFI, Bluetooth, GPS and the like, and actually operates under an android platform. U3 sets at least 5I/O ports (specifically, GPIO ports): I/O1, I/O2, I/O3, I/O4, I/O5. Wherein, the I/O1 is configured as an input port for detecting the driving state of the vehicle. In this embodiment, the reverse detection module is configured to receive a reverse detection signal, i.e., connected to OUT of the reverse detection module U6. The I/O2, the I/O3 and the I/O4 are output ports and are electrically connected with the address signal port A, B, C of the U1 respectively, for example, directly or through a triode switch circuit. In this embodiment, the triode switch circuit is composed of NPN type triodes Q1, Q2, Q3 and voltage-dividing current-limiting resistors R6, R7, R8, R9, and R10. The I/O5 is a PWM output port and is connected with the PWM port of the multi-path back light control chip U4.

U4 is selected according to the requirement in practical application, such as 6-channel backlight control chips tps61196-q1 of TI.

U5 is a liquid crystal display screen, which contains multiple LED backlight, and is generally applied in4 or 6 ways.

U6 is a reverse detection module, IN represents reverse signal input, OUT represents reverse detection signal processed by U6, low represents reverse signal coming, and high represents no reverse signal (default state). In practical application, the U6 may be a detection circuit composed of a photoelectric coupler or a triode combination detection circuit.

The working principle of the present invention is explained below:

firstly, power-on initialization, wherein the I/O1 is configured as an input port and is high by default, and the I/O2, the I/O3 and the I/O4 are configured as output ports and are high by default; I/O5 is configured as a PWM output port.

Secondly, the U3 judges the vehicle running state through detecting the I/O1, when the U3 detects that the I/O1 is IN a low level, a reverse signal comes, the vehicle is judged to be IN a reverse state, at the moment, the U3 keeps the I/O4 IN a high level, meanwhile, the I/O3 is controlled to be low, the I/O2 is high, the U1 collects the IN2 channel voltage (the partial voltage of the R _ RL and the R3 on the rear left side), the partial voltage is converted into an 8-bit digital signal (represented by the D2) through the U1, and the U3 reads the D2 and stores the digital signal into an internal memory of the U3; after time T, U3 keeps I/O4 high, controls I/O3 low and I/O2 low, U1 collects IN3 channel voltage (divided voltage of rear right voltage R _ RR and R4), U1 converts it into 8-bit digital signal (denoted by D3), U3 reads D3 and stores it IN U3 internal memory; after the time T, the U3 controls the I/O4 to be low level, controls the I/O3 to be high and controls the I/O2 to be high, the U1 collects the IN4 channel voltage and converts the IN4 channel voltage into an 8-bit digital signal (represented by D4), and the U3 reads the D4 and stores the D4 IN an internal memory of the U3; at this time, the U3 performs an internal software calculation to obtain an average value of the above three data amounts, which is represented by DOUT (D2+ D3+ D4)/3, and the U3 controls the I/O5 to output PWM with a duty ratio of DOUT/255 and a frequency of F. After the state is maintained for the time T1 (the time of T1 can be adjusted according to needs), the I/O1 is detected again, if the time is low, the data is collected again and updated, and therefore the purpose of adjusting the backlight of the display screen in real time when the vehicle backs is achieved.

When the U3 detects that the I/O1 is at a high level, the signal indicates that no reverse signal comes, the automobile is judged to be IN a traveling state, at the moment, the U3 keeps the I/O4 at the high level, and controls the I/O3 to be high and the I/O2 to be high, the U1 collects the IN0 channel voltage (the partial voltage of the R _ FL and the R1 at the front and the left sides) and converts the voltage into an 8-bit digital signal (represented by D0) through the U1, and the U3 reads the D0 and stores the D0 IN the internal memory of the U3; after time T, U3 keeps I/O4 at high level, controls I/O3 at high level and I/O2 at low level, U1 collects IN1 channel voltage (the partial voltage of front right voltage R _ FR and R2), converts the voltage into 8-bit digital signal (represented by D1) through U1, and U3 reads D1 and stores the digital signal IN U3 internal memory; after the time T, the U3 controls the I/O4 to be low level, controls the I/O3 to be high and controls the I/O2 to be high, the U1 collects the IN4 channel voltage and converts the IN4 channel voltage into an 8-bit digital signal (represented by D4), and the U3 reads the D4 and stores the D4 IN the U3 internal memory; at this time, the U3 performs internal software to calculate the average value of the three data quantities, which is expressed by DOUT, wherein DOUT is (D0+ D1+ D4)/3, U3 controls I/O5 to output PWM with the duty ratio of DOUT/255 and the frequency of F, after the state is kept for a time T1 (the time of T1 can be adjusted according to needs), I/O1 is re-detected, and if the time is high, the data is re-collected and updated, so that the purpose of adjusting the backlight of the display screen in real time when the vehicle travels is achieved.

In addition, the invention provides a numerical control backlight adjusting method based on the vehicle running state, wherein the method comprises the following steps:

providing a digitally controlled dimming backlight circuit as described above;

every preset time, the U3 judges the driving state of the vehicle by detecting I/O1, if the vehicle is judged to be in a reverse state, the U1 sequentially collects the light intensity of the left side and the right side behind the vehicle and in the vehicle and converts the light intensity into digital quantities D2, D3 and D4 by arranging I/O2, I/O3 and I/O4, the U3 reads D2, D3 and D4 and stores the digital quantities into an internal memory, and the U3 calculates the average value DOUT of the three data, wherein the DOUT is (D2+ D3+ D4)/3; if the vehicle is judged to be in a traveling state, the I/O2, the I/O3 and the I/O4 are arranged, so that the U1 sequentially collects the light intensity of the left side and the right side in front of the vehicle and the light intensity in the vehicle and converts the light intensity into digital quantities D0, D1 and D4, the U3 reads the digital quantities D0, D1 and D4 and stores the digital quantities into an internal memory of the U3, and the U3 calculates the average value DOUT of the three data, namely (D0+ D1+ D4)/3;

u3 controls I/O5 to output a PWM signal with a duty cycle of DOUT/255 and a frequency of F.

Compared with the prior art, the invention has the following innovation:

1. the backlight digital regulation control of the vehicle-mounted display screen in different driving states is realized by utilizing the resistance characteristic of the photoresistor and the control characteristic of the triode switch, adopting the control technology of an I/O port and the multi-channel AD acquisition technology.

2. The method comprises the steps that numerical control adjustment control is applied, three paths of light intensity are collected in a certain time under different driving states, after the three paths of light intensity are converted through 8-bit ADC respectively, the three paths of light intensity are processed by a CPU to obtain an average digital quantity DOUT, meanwhile, the CPU outputs a PWM signal with a duty ratio DOUT/255 by taking the DOUT as a variable parameter, the backlight is adjusted and controlled, and numerical control adjustment of the backlight is achieved; the method simultaneously acquires the brightness of the environment inside and outside the vehicle according to the running state of the vehicle, and simultaneously calculates the average value, so that the current brightness value is closer to the current environment, the real-time performance and the accuracy are higher, and the method is more suitable for various vehicle condition environments in the running process.

3. Adopt outside ADC's conversion mode, can make ADC supply voltage be higher than CPU's power supply (present most CPU supply voltage is 3.3V or 1.8V) to be favorable to improving the interference killing feature of outside collection signal, because the different positions in the photoresistor need the installation car, the condition of wiring length appears, and the wiring length leads to that the impedance is big, receives external disturbance easily, and the supply voltage who improves the ADC is favorable to improving the interference killing feature of signal line.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A numerical control adjustment backlight circuit based on a vehicle driving state is characterized by comprising a processor chip U3 and a five-way light intensity acquisition circuit, wherein the U3 is provided with at least 5I/O ports, I/O1 is configured as an input port and used for detecting the vehicle driving state, I/O2, I/O3 and I/O4 are output ports and are respectively and electrically connected with an address signal port A, B, C of a multi-channel ADC chip U1 of the five-way light intensity acquisition circuit, and I/O5 is a PWM output port and is connected with a multi-way backlight control chip U4; the five light intensity acquisition circuits are used for acquiring the light intensity of the left side and the right side in front of or behind the vehicle and the light intensity in the vehicle according to the signal A, B, C, converting the light intensity into digital quantity and sending the digital quantity to the U3, wherein the digital quantity output range is between 0 and 255; the U3 is used for carrying out average calculation on the received light intensity of the left and right sides in front or the left and right sides in back and the light intensity in the automobile, dividing the obtained average value DOUT by 255, and simultaneously controlling the I/O5 to output a PWM signal with the duty ratio of DOUT/255 and the frequency F, wherein the frequency F is the PWM frequency of the multi-path back light control chip U4.

2. The numerical control adjusting backlight circuit based on the driving state of the vehicle as claimed IN claim 1, wherein the five light intensity acquisition circuits comprise light dependent resistors R _ FL, R _ FR, R _ RL, R _ RR and RB, a multi-channel ADC chip U1 and voltage dividing and current limiting resistors R1, R2, R3, R4 and R5, wherein R _ FR, R _ FL, R _ RL, R _ RR and RB are respectively connected IN series with R1, R2, R3, R4 and R5 between VCC and GND, and wherein the analog input channels IN0-IN4 of the multi-channel ADC chip U1 are respectively connected between R _ FR, R _ FL, R _ RL, R _ RR and RB and R1, R2, R3, R4 and R5.

3. The digitally controlled dimming backlight circuit based on vehicle driving conditions of claim 1, further comprising a level matching network U2, U2 for matching the level of the digital quantity output of the multi-channel ADC chip U1 with the digital quantity input of the processor chip.

4. The numerical control adjusting backlight circuit based on the driving state of the vehicle as claimed in claim 3, wherein U2 is a level conversion IC or a voltage dividing resistor network.

5. The digitally controlled backlight circuit for adjusting brightness based on the driving state of a vehicle according to claim 1, wherein I/O2, I/O3, I/O4 and A, B, C are connected via respective triode switch circuits.

6. The numerical control adjusting backlight circuit based on the vehicle driving state as claimed in claim 1, wherein the multi-channel ADC chip U1 is an 8-bit successive approximation ADC chip.

7. The digitally controlled dimming backlight circuit according to claim 1, wherein the I/O1 is adapted to receive a reverse signal.

8. The numerical control adjusting backlight circuit based on the driving state of the vehicle as claimed IN claim 7, further comprising a reverse detection module U6, wherein IN represents a reverse signal input, OUT represents a reverse detection signal processed by U6, low represents a reverse signal, high represents no reverse signal, and OUT is connected with I/O1.

9. The numerical control adjusting backlight circuit based on the driving state of the vehicle as claimed in claim 8, wherein the reverse detection module U6 is a detection circuit composed of a photoelectric coupler or a detection circuit composed of a triode.

10. A numerical control backlight adjusting method based on a vehicle running state is characterized by comprising the following steps:

providing a digitally controlled tuned backlight circuit according to any preceding claim;

every preset time, the U3 judges the driving state of the vehicle by detecting I/O1, if the vehicle is judged to be in a reverse state, the U1 sequentially collects the light intensity of the left side and the right side behind the vehicle and in the vehicle and converts the light intensity into digital quantities D2, D3 and D4 by arranging I/O2, I/O3 and I/O4, the U3 reads D2, D3 and D4 and stores the digital quantities into an internal memory, and the U3 calculates the average value DOUT of the three data, wherein the DOUT is (D2+ D3+ D4)/3; if the vehicle is judged to be in a traveling state, the I/O2, the I/O3 and the I/O4 are arranged, so that the U1 sequentially collects the light intensity of the left side and the right side in front of the vehicle and the light intensity in the vehicle and converts the light intensity into digital quantities D0, D1 and D4, the U3 reads the digital quantities D0, D1 and D4 and stores the digital quantities into an internal memory of the U3, and the U3 calculates the average value DOUT of the three data, namely (D0+ D1+ D4)/3;

u3 controls I/O5 to output a PWM signal with a duty cycle of DOUT/255 and a frequency of F.

Images