Vehicle and instrument circuit thereof

Abstract

The utility model discloses a vehicle and an instrument circuit thereof. The vehicle comprises a dimming switch circuit and a dimming signal acquisition circuit comprising a voltage division circuit, a switch type filter circuit and a control unit. The first connecting end of the switch type filter circuit is connected with the voltage division circuit, and the second connecting end is connected with the control unit. The switch type filter circuit is switched on when the voltage signal output by the dimming switch circuit is larger than the preset voltage, otherwise, the switch type filter circuit is switched off, and the control unit collects the first signal and the second signal respectively and is used for adjusting the brightness of the instrument display screen. Since the switch type filter circuit is conducted only when the voltage signal output by the dimming switch is greater than the preset voltage, when the first signal jumps to the second signal, even if a zigzag signal with staggered high and low levels exists in the middle, the voltage corresponding to the high level appearing in the zigzag shape is not higher than the preset voltage, so that the dimming effect is improved. The controller still collects the second signal, that is, disordered signals cannot be collected in the middle, so that the problem of splash screen of the instrument display screen is solved.

Description

Technical Field

[0001] The present application relates to the technical field of automobile instruments, and in particular to a vehicle and an instrument circuit thereof. Background Art

[0002] In the rapid development of automobile instrument display screens, the problem of screen flicker has always been one of the most important research directions. When a car is driving in a tunnel or at night, the instrument display screen lights up when the position light is turned on. Users can adjust the brightness of the instrument display screen by adjusting the dimmer switch.

[0003] Under normal circumstances, the falling edge and rising edge of the waveform of the dimmer switch output signal are similar in shape and both are smooth vertical lines. However, when the frequency of the dimmer switch output signal jumps, that is, high and low level states appear alternately in a short period of time, the falling edge of the waveform presents a sawtooth slow-down curve instead of a steep vertical line. This will cause the duty cycle of the dimmer switch output signal sampled at the instrument end to change differentially, which in turn causes the brightness of the instrument display to jump rapidly, that is, the instrument display screen flickers.

[0004] It can be seen that how to solve the problem of screen flickering and improve user experience is a technical problem that needs to be urgently solved by technical personnel in this field. Utility Model Content

[0005] In view of this, one aspect of the present application provides an instrument circuit of a vehicle, wherein the instrument circuit is used to be connected to an instrument display screen to adjust the brightness of the instrument display screen, and the instrument circuit includes:

[0006] A dimming switch circuit, used to output a voltage signal for adjusting the brightness of the instrument display screen;

[0007] A dimming signal acquisition circuit, comprising: a voltage divider circuit, a switch type filter circuit and a control unit;

[0008] The voltage divider circuit is connected between the dimming switch circuit and the switch type filter circuit, and the switch type filter circuit is connected between the voltage divider circuit and the control unit;

[0009] The switching filter circuit is turned on when the voltage signal is greater than a preset voltage, and the control unit receives a first signal; the switching filter circuit is turned off when the voltage signal is not greater than the preset voltage, and the control unit receives a second signal; the control unit is connected to the instrument display screen, and is used to adjust the brightness of the instrument display screen according to the first signal and the second signal.

[0010] Preferably, the voltage-dividing circuit comprises a first voltage-dividing resistor and a second voltage-dividing resistor connected in series between the dimming switch circuit and the ground terminal;

[0011] The switch type filter circuit comprises a first connection end and a second connection end, wherein the first connection end is connected between the first voltage dividing resistor and the second voltage dividing resistor;

[0012] The control unit is connected to the second connection end.

[0013] Preferably, the switch type filter circuit comprises a first transistor;

[0014] The base of the first transistor is connected between the first voltage-dividing resistor and the second voltage-dividing resistor, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to the DC power supply terminal and the control unit respectively.

[0015] Preferably, the switch type filter circuit further comprises: a first filter capacitor and a second filter capacitor;

[0016] The first filter capacitor is connected between the base of the first transistor and the ground terminal, and the second filter capacitor is connected between the collector of the first transistor and the ground terminal.

[0017] Preferably, the switch type filter circuit further comprises: a first resistor;

[0018] The first resistor is connected between the collector of the first transistor and the DC power supply.

[0019] Preferably, the switch type filter circuit further comprises: a second resistor;

[0020] The second resistor is connected between the collector of the first transistor and the control unit.

[0021] Preferably, the dimming switch circuit comprises: a signal modulation circuit, a third resistor and a discharge device, and the third resistor is a zero-ohm resistor;

[0022] The signal modulation circuit is used to convert the low-frequency signal into a high-frequency PWM signal with a variable pulse width;

[0023] One end of the third resistor is connected to the signal modulation circuit, the other end of the third resistor is respectively connected to one end of the discharge device and the voltage divider circuit, and the other end of the discharge device is grounded.

[0024] Preferably, the discharge device includes a fourth resistor.

[0025] Preferably, the discharge device includes a third capacitor.

[0026] Another aspect of the present application provides a vehicle, including an instrument display screen and an instrument circuit of the vehicle, wherein the instrument circuit is connected to the instrument display screen and is used to adjust the brightness of the instrument display screen.

[0027] The present application provides a vehicle and its instrument circuit. Since the switch-type filter circuit is turned on only when the voltage signal output by the dimmer switch is greater than a preset voltage, when the first signal jumps to the second signal, even if there is a sawtooth-shaped signal of alternating high and low levels in the middle, and the voltage corresponding to the high level appearing in the sawtooth is not higher than the preset voltage, the switch-type filter circuit is turned off, and the controller still collects the second signal. Therefore, the switch-type filter circuit will not be on and off, and thus the controller will not mistakenly collect the first signal as the second signal, nor will it mistakenly collect the second signal as the first signal, thereby overcoming the screen flickering caused by the sawtooth-shaped slow-fall curve of the falling edge of the dimmer switch output signal, and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A waveform diagram of an output signal of a dimming switch provided in the present application;

[0029] Figure 2 A vehicle provided by an embodiment of the present application;

[0030] Figure 3 A principle block diagram of an instrument circuit of a vehicle provided in an embodiment of the present application;

[0031] Figure 4 for Figure 3 A circuit diagram of a dimming signal acquisition circuit in an instrument circuit of the vehicle shown;

[0032] Figure 5 A circuit diagram of a dimming switch circuit provided in an embodiment of the present application;

[0033] Figure 6 for Figure 3 Circuit diagram of a dimmer switch circuit in the instrument circuit of the vehicle shown.

[0034] The accompanying drawings are marked as follows: instrument circuit 1, instrument display screen 2, dimming switch circuit 3, dimming signal acquisition circuit 4, voltage divider circuit 5, switch type filter circuit 6, control unit 7, signal modulation circuit 8, discharge device 9. DETAILED DESCRIPTION

[0035] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0036] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0037] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0038] When the vehicle is driving in a dimly lit environment, the position lights need to be turned on and the instrument display screen lights up. When the user adjusts the brightness of the instrument display screen through the dimmer switch, if the signal from the dimmer switch is unstable or abnormal, the LCD screen will occasionally flicker.

[0039] Specifically, usually, the falling edge of the waveform of the output signal of the dimming switch is in the shape of a steep vertical line, and the falling edge and the rising edge are similar in shape, both of which are smooth vertical lines. Figure 1 This is a waveform diagram of a dimming switch output signal provided by the present application. However, Figure 1 As shown, when the falling edge of the waveform of the output signal of the dimmer switch presents a sawtooth slow-fall curve, it will cause high and low level signals to appear alternately in a short period of time. At the sawtooth portion, the controller will mistakenly collect the low level signal as a high level signal, or mistakenly collect the high level signal as a low level signal, resulting in a sudden adjustment of the brightness of the instrument display when the controller adjusts the brightness of the instrument display, that is, the instrument LCD screen flickers.

[0040] Figure 2 A vehicle provided in an embodiment of the present application includes: an instrument circuit 1 and an instrument display screen 2, wherein the instrument circuit 1 is connected to the instrument display screen 2 and is used to adjust the brightness of the instrument display screen 2. It should be noted that the vehicle including the instrument circuit 1 includes but is not limited to a sedan, SUV, MPV, off-road vehicle, pickup truck or other power-driven non-track-borne vehicle.

[0041] In order to solve the above technical problems, an embodiment of the present application provides a vehicle instrument circuit 1, which is connected to an instrument display screen 2 and is used to adjust the brightness of the instrument display screen 2. Figure 3A schematic diagram of a vehicle instrument circuit provided by an embodiment of the present application is shown in FIG. Figure 3 As shown, the instrument includes: a dimming switch circuit 3 and a dimming signal acquisition circuit 4, wherein the dimming signal acquisition circuit 4 includes a voltage divider circuit 5, a switch type filter circuit 6 and a control unit 7.

[0042] like Figure 3 As shown, in an optional embodiment, the dimming switch circuit 3 is connected to the dimming signal acquisition circuit 4, the dimming signal acquisition circuit 4 is connected to the instrument display screen 2, the dimming switch circuit 3 is used to output a voltage signal for adjusting the brightness of the instrument display screen 2, and the dimming signal acquisition circuit 4 is used to adjust the brightness of the instrument display screen 2 according to the voltage signal output by the dimming switch circuit 3.

[0043] The voltage divider circuit 5 is connected between the dimming switch circuit 3 and the switch type filter circuit, and the switch type filter circuit 6 is connected between the voltage divider circuit 5 and the control unit 7.

[0044] In an optional embodiment, if Figure 3 As shown, the voltage divider circuit 5 includes a first voltage divider resistor R50 and a second voltage divider resistor R51 connected in series between the dimming switch circuit 3 and the ground terminal, and the switching filter circuit 6 includes a first connection end and a second connection end, the first connection end is connected between the first voltage divider resistor R50 and the second voltage divider resistor R51, and the second connection end is connected to the control unit 7.

[0045] In a specific embodiment, the switching filter circuit 6 is turned on when the voltage signal is greater than a preset voltage, and the control unit 7 receives a first signal. The switching filter circuit 6 is turned off when the voltage signal is not greater than the preset voltage, and the control unit 7 receives a second signal. The control unit 7 is connected to the instrument display screen 2 and is used to adjust the brightness of the instrument display screen 2 according to the first signal and the second signal.

[0046] like Figure 1As shown, when the falling edge of the waveform of the output signal of the dimming switch circuit 3 presents a sawtooth slow-fall curve, there will be high and low levels that fluctuate, however, the high level that appears in the sawtooth curve will not be higher than the high level under the normal signal, therefore, the present application adds a switch-type filter circuit 6 in the dimming signal acquisition circuit 4, which is turned on when the output voltage signal of the dimming switch circuit 3 is greater than the preset voltage, at which time the control unit 7 acquires the first signal, if the first signal jumps to the second signal, even if there is a sawtooth signal of high and low levels in the middle, because the voltage corresponding to the high level that appears in the sawtooth will not be higher than the preset voltage, the switch-type filter circuit 6 is turned off, and the controller still acquires the second signal. For ease of understanding, an example will be given below. For example, the preset voltage is 4.2V. When the output voltage of the dimming switch circuit 3 is greater than 4.2V, the control unit 7 collects the first signal. If it is not greater than 4.2V, the control unit 7 collects the second signal. Even if there is a sawtooth signal mutation in the middle of the jump from the first signal to the second signal, the voltage of the mutation will not be higher than 4.2V, so the control unit 7 will eventually collect the second signal. Therefore, the control unit 7 will not collect disordered signals, thereby avoiding the screen flashing of the instrument display screen 2 caused by the falling edge of the waveform of the output signal of the dimming switch circuit 3 showing a sawtooth slow-down curve.

[0047] In fact, the switch filter circuit 6 acts as a switch. When the output voltage of the dimming switch circuit 3 is greater than the preset voltage, the switch filter circuit 6 is turned on, otherwise it is turned off, thereby preventing the control unit 7 from collecting disordered signals.

[0048] In addition to improving the hardware circuit of the instrument circuit 1 to overcome the screen flickering problem, the probability of screen flickering of the instrument display screen 2 can also be reduced by improving the software control method. Specifically, in an optional embodiment, the control method of the instrument display screen 2 provided in the embodiment of the present application includes:

[0049] S10: Obtaining a PWM signal output by the dimming switch circuit for adjusting the brightness of the display screen;

[0050] It should be noted that if Figure 3 As shown, the executor of the control method provided in the embodiment of the present application is a control unit 7, which may be a vehicle domain controller or a whole vehicle controller, and the present application does not make any specific limitation on this.

[0051] In a specific embodiment, a PWM signal for adjusting the brightness of the instrument display screen 23 output by the dimming switch circuit 3 is obtained through step S10. It can be understood that the PWM signal output by the dimming switch circuit 3 passes through the voltage divider circuit 5 and the switching filter circuit 6, and then is transmitted to the control unit 7, so that the control unit 76 adjusts the brightness of the instrument display screen 2 according to the PWM signal.

[0052] S11: Determine a rate of change of a timing characteristic of a PWM signal; wherein the timing characteristic includes at least one of a frequency and a duty cycle;

[0053] S12: When the rate of change is greater than the threshold, the brightness of the instrument display screen is adjusted according to the duty cycle;

[0054] S13: When the rate of change is not greater than the threshold, the instrument display screen is controlled to maintain the current brightness.

[0055] Furthermore, after the control unit 7 obtains the PWM signal output by the dimming switch circuit 3 through step S10, it determines the change rate of the timing characteristics of the PWM signal, so as to determine whether to adjust the brightness of the instrument display screen 2 according to the change rate of the timing characteristics, wherein the timing characteristics include at least one of the frequency and the duty cycle.

[0056] Specifically, when the rate of change is greater than the threshold, the current PWM signal is determined to be a signal that requires adjustment of the instrument display screen 2. At this time, the brightness of the instrument display screen 2 is adjusted according to the duty cycle of the PWM signal. However, when the rate of change is not greater than the threshold, the current PWM signal is determined to be a signal that does not require adjustment of the instrument display screen 2, that is, the current PWM signal is determined to be a signal collected when the signal is unstable, and at this time, the instrument display screen 2 can be controlled to maintain the current brightness.

[0057] It should be noted that the rate of change of the timing characteristics can be the rate of change of frequency or the rate of change of duty cycle, or the rate of change of frequency and the rate of change of duty cycle. In addition, the rate of change can be the rate of change between the current moment and the previous moment, or the rate of change within a preset time period, which is not limited in this application.

[0058] Therefore, the control method of the vehicle display screen provided in the embodiment of the present application determines whether to adjust the brightness of the display screen according to the change rate of the timing characteristics of the PWM signal output by the dimming switch circuit 3, thereby avoiding PWM signal instability, that is, when the PWM signal occasionally jumps, the PWM signal is mistakenly regarded as a brightness adjustment signal, causing the display screen to flicker, thereby improving the adjustment accuracy of the dimming switch circuit 3 on the brightness of the display screen, and thereby improving the user experience.

[0059] In an optional embodiment, the threshold includes a first threshold and a second threshold; when the change rate is greater than the threshold, the brightness of the instrument display screen is adjusted according to the duty cycle, including:

[0060] If the rate of change of frequency between the current moment and the previous moment, and the rate of change of frequency between the current moment and the next moment are both greater than the first threshold, and the rate of change of duty cycle between the current moment and the previous moment, and the rate of change of duty cycle between the current moment and the next moment are both greater than the second threshold, the brightness of the instrument display screen is adjusted according to the duty cycle.

[0061] It is understandable that the probability of the timing characteristics of the PWM signal jumping back and forth twice in succession is very low. Therefore, it is possible to determine whether to adjust the brightness of the instrument display screen 2 based on the change rate of the timing characteristics between the current moment and the previous moment, and between the current moment and the next moment.

[0062] In an optional embodiment, in order to improve the adjustment accuracy of the instrument display screen 2, the timing characteristics preferably include frequency and duty cycle, and the threshold includes a first threshold and a second threshold. When determining whether the timing characteristic change rate is greater than the threshold, specifically, if the frequency change rate between the current moment t1 and the previous moment t2, and the frequency change rate between the current moment t1 and the next moment t3 are both greater than the first threshold, and the duty cycle change rate between the current moment t1 and the previous moment t2, and the duty cycle change rate between the current moment t1 and the next moment t3 are both greater than the second threshold, it is determined that the timing characteristic change rate is greater than the threshold, and the brightness of the instrument display screen 2 is adjusted according to the duty cycle.

[0063] Based on the above embodiment, as an optional embodiment, the brightness of the instrument display screen is adjusted according to the duty cycle, including:

[0064] Determine a first brightness level of the instrument display screen corresponding to the current duty cycle, and a second brightness level of the instrument display screen corresponding to the next duty cycle;

[0065] The brightness of the control instrument display is adjusted from the first brightness level to the second brightness level.

[0066] In a specific embodiment, the duty cycle of the PWM signal output by the dimming switch circuit 3 determines the brightness of the instrument display screen 2. The larger the duty cycle, the brighter the instrument display screen 2. Therefore, when adjusting the brightness of the instrument display screen 2, it can be adjusted according to the duty cycle.

[0067] Specifically, different duty cycles correspond to different brightness levels of the instrument display screen 2. Therefore, the first brightness level of the instrument display screen 2 corresponding to the duty cycle at the current moment and the second brightness level corresponding to the duty cycle at the next moment are first determined, and then the brightness of the instrument display screen 2 is controlled to be adjusted from the first brightness level to the second brightness level.

[0068] It should be noted that the mapping relationship between the duty cycle and the brightness level in the embodiment of the present application is not specifically limited. Table 1 is a schematic mapping relationship between the duty cycle and the brightness level provided in the implementation of the present application.

[0069] Table 1

[0070]

[0071] As shown in the mapping relationship in Table 1, if the duty cycle at the current moment is in the range of 10%-20%, the first brightness level is the second level, and when the duty cycle at the next moment is in the range of 30%-40%, the second brightness level is the third level, at this time, the control instrument display screen 2 is adjusted from the brightness of the second level to the brightness of the third level.

[0072] Based on the above embodiment, as an optional embodiment, controlling the brightness of the instrument display screen to be adjusted from the first brightness level to the second brightness level includes:

[0073] When the first brightness level and the second brightness level are non-adjacent levels, the brightness of the instrument display screen is controlled to be adjusted step by step from the first brightness level.

[0074] It can be understood that when the first brightness level and the second brightness level are non-adjacent levels, if the brightness of the instrument display screen 2 is directly jumped from the first brightness level to the second brightness level, the brightness changes greatly, which gives the user a visual experience of a flashing screen, and the visual experience is not good. Therefore, in order to solve this technical problem, the embodiment of the present application adjusts the brightness of the instrument display screen 2 from the first brightness to the second brightness level step by step. For example, as shown in Table 1, if the duty cycle at the current moment is in the range of 10%-20%, the first brightness level is the second level, and the duty cycle at the next moment is in the range of 50%-60%, the second brightness level is the fifth level. At this time, when adjusting the brightness of the instrument display screen 2, first adjust from the second level to the third level, then from the third level to the fourth level, and finally from the fourth level to the fifth level.

[0075] In an optional embodiment, controlling the brightness of the instrument display screen to be adjusted from a first brightness level to a second brightness level includes:

[0076] When the first brightness level and the second brightness level are non-adjacent levels, a control signal is generated to control the brightness of the instrument display screen to be adjusted from the first brightness level to a third brightness level, where the third brightness level is the next brightness level of the first brightness level;

[0077] After the first preset time, if the duty cycle of the control signal is equal to the duty cycle corresponding to the first brightness level, the brightness of the instrument display screen is controlled to remain at the third brightness level;

[0078] If the duty cycle of the control signal is not equal to the duty cycle corresponding to the first brightness level, the brightness of the instrument display screen is controlled to be adjusted from the third brightness level to the next brightness level of the third brightness level.

[0079] In a specific embodiment, when the brightness of the instrument display screen 2 is adjusted, the adjustment may be caused by a misjudgment, that is, the brightness of the instrument display screen 2 may be adjusted due to screen flickering. If the first brightness level and the second brightness level are non-adjacent levels, then in the process of controlling the brightness of the instrument display screen 2 to be adjusted from the first brightness level to the second brightness level, the signal may be adjusted to any intermediate level and then return to normal, that is, the duty cycle of the PWM signal is restored to the duty cycle corresponding to the first brightness level. In this case, if the brightness adjustment is continued, the severity of the screen flickering will be aggravated. If the brightness of the instrument display screen 2 is adjusted back to the first brightness level and the adjustment is returned, the severity of the screen flickering will also be aggravated.

[0080] For example, if the first brightness level is level 2 and the second brightness level is level 5, when adjusting the brightness of the instrument display screen 2, first adjust it from level 2 to level 3, then adjust it from level 3 to level 4, and finally adjust it from level 4 to level 5. In this process, after adjusting to level 3 or level 4, the signal may return to normal, that is, the duty cycle of the PWM signal returns to the duty cycle corresponding to level 2. At this time, there is no need to continue adjusting the brightness of the instrument display screen 2, nor is there any need to adjust the brightness back to level 2.

[0081] Therefore, in order to reduce the severity of screen flicker, in an optional embodiment, when the brightness of the instrument display screen 2 is controlled to be adjusted from a first brightness level to a second brightness level, if it is determined that the first brightness level and the second brightness level are non-adjacent levels, a control signal is generated, and the control signal is used to control the brightness of the instrument display screen 2 to be adjusted from the first brightness level to a third brightness level, wherein the third brightness level is the next brightness level of the first brightness level.

[0082] Furthermore, after the first preset time, it is determined whether the duty cycle corresponding to the control signal is equal to the duty cycle corresponding to the first brightness level, that is, whether the PWM signal returns to normal. In fact, this is also a way to determine whether the current brightness adjustment causes screen flickering.

[0083] If the duty cycle of the control signal is equal to the duty cycle corresponding to the first brightness level, it is determined that the PWM signal has returned to normal, that is, it is determined that the current brightness adjustment is an abnormal adjustment, that is, it is determined that screen flickering has occurred. At this time, in order to reduce the severity of screen flickering, the brightness of the control instrument display 2 is maintained at the third brightness level.

[0084] If the duty cycle of the control signal is not equal to the duty cycle corresponding to the first brightness level, it is determined that the current brightness adjustment is a normal adjustment, and the brightness of the control instrument display screen 2 is adjusted from the third brightness level to the next brightness level of the third brightness level, that is, the brightness of the control instrument display screen 2 is adjusted step by step until the brightness is adjusted from the first brightness level to the second brightness level.

[0085] It is worth noting that after each brightness adjustment, it is necessary to determine whether the signal has returned to normal after a first preset time interval, that is, to determine whether the duty cycle corresponding to the control signal is equal to the duty cycle corresponding to the first brightness level. For example, a level adjustment is performed every 0.2 seconds, and during this time, it is determined whether the signal has returned to normal, thereby reducing the severity of screen flickering.

[0086] In a specific embodiment, determining a first brightness level of the instrument display screen corresponding to the current duty cycle and a second brightness level of the instrument display screen corresponding to the next duty cycle includes:

[0087] From the brightness level table including the mapping relationship between duty cycle range and brightness level, determine the brightness level corresponding to the duty cycle range where the current duty cycle is located as the first brightness level, and determine the brightness level corresponding to the duty cycle range where the duty cycle is located at the next moment as the second brightness level.

[0088] It is understandable that the duty cycle determines the brightness of the instrument display screen 2. The higher the duty cycle, the brighter the instrument display screen 2. When determining the brightness level of the instrument display screen 2 according to the duty cycle, it is determined based on the mapping relationship between the duty cycle range and the brightness level.

[0089] It should be noted that when increasing the brightness, it is necessary to adjust according to the brightness increase level table, and when decreasing the brightness, it is necessary to adjust according to the brightness decrease level table. The difference between the minimum value in the duty cycle range of the first specified level in the brightness increase level table and the maximum value in the duty cycle range of the second specified level in the brightness decrease level table is greater than the preset value, wherein the first specified level is the previous level of the second specified level.

[0090] The ranges of adjacent brightness levels in the brightness increase level table and the brightness decrease level table are different. This can prevent the vehicle from shaking slightly during driving, causing the dimming switch to shake, and then causing the brightness of the instrument display screen 2 to be adjusted incorrectly.

[0091] Table 2 is a schematic mapping relationship between duty cycle and brightness level provided in the implementation of this application. As shown in Table 2, Table 2 is a brightness reduction level table, and Table 1 is a brightness increase level table.

[0092] Table 2

[0093]

[0094] For ease of understanding, the following will be explained in conjunction with Table 1 and Table 2. As shown in Table 1 and Table 2, in the brightness increase level table, the duty cycle range corresponding to the third level is 30%≤X<40%, where X is the duty cycle, and in the brightness decrease level table, the duty cycle range corresponding to the second level is 18%<X≤28%, and the minimum value in the three-level range is 2% higher than the maximum value in the second-level range, that is, the difference between the minimum value in the duty cycle range of the first specified level in the brightness increase level table and the maximum value in the duty cycle range of the second specified level in the brightness decrease level table is greater than the preset value of 2%.

[0095] In a specific embodiment, when the brightness of the instrument display screen 2 needs to be adjusted from the third level to the second level, if the brightness increase and brightness decrease both use the brightness increase level table, that is, when Table 1 is used, then the brightness is adjusted from the third level to the second level. As long as the duty cycle is less than 30%, the brightness must be adjusted. For example, when the vehicle shakes, resulting in a duty cycle of 29.9%, the brightness must also be adjusted. At this time, alcohol will cause misjudgment.

[0096] Therefore, in order to avoid the above problems, a separate brightness reduction level table is set, and the difference between the minimum value of the third gear and the maximum value of the second gear is 2%. When adjusting from the third gear to the second gear, the duty cycle needs to be less than or equal to 28% to adjust from the third gear to the second gear. In this way, it is possible to avoid misjudgment of brightness adjustment caused by vehicle shaking, thereby improving the accuracy of brightness adjustment.

[0097] In an optional embodiment, the brightness level table includes a brightness increase level table and a brightness decrease level table. When the first brightness level and the second brightness level are non-adjacent levels, the brightness of the control instrument display screen 2 is adjusted step by step from the first brightness level, including:

[0098] If the brightness corresponding to the first brightness level is lower than the brightness corresponding to the second brightness level, the brightness of the instrument display screen 2 is controlled to be gradually increased from the first brightness level according to the brightness increase level table;

[0099] If the brightness corresponding to the first brightness level is higher than the brightness corresponding to the second brightness level, the brightness of the instrument display screen 2 is controlled to be gradually reduced from the first brightness level according to the brightness reduction level table.

[0100] In a specific embodiment, when adjusting the brightness of the instrument display screen 2 , in order to enhance the user's visual experience and reduce the probability of screen flickering, it is necessary to perform a primary adjustment from the first brightness level.

[0101] In an optional embodiment, the method for controlling a vehicle instrument display screen provided in the embodiment of the present application further includes:

[0102] Determine the mean value of the time series feature within a second preset time length; wherein the second preset time length is the time length during which the instrument display screen maintains the current brightness;

[0103] If the difference between the current time series characteristics and the mean value is greater than the preset difference, the instrument display screen is controlled to maintain the current brightness.

[0104] In a specific embodiment, in order to reduce the probability of screen flickering, the average of the timing characteristics within the second preset time length is obtained, and the timing characteristics may include frequency and duty cycle. It should be noted that the second preset time length refers to the time length corresponding to the current brightness maintained by the instrument display screen 2, that is, the time length during which the PWM signal remains stable, and the second preset time length obtains a time length that is closest to the current moment.

[0105] After obtaining the mean value of the timing characteristics, it is determined whether the difference between the timing characteristics at the current moment and the mean value is greater than the preset difference. If it is greater, it is determined that the PWM signal collected at the current moment is a mutation signal (i.e., an abnormal signal). In order to avoid screen flickering, the instrument display screen 2 is controlled to maintain the current brightness. If it is not greater, it is determined that the PWM signal is a normal signal, and the brightness of the instrument display screen 2 is adjusted according to the duty cycle of the PWM signal.

[0106] Therefore, in the vehicle instrument circuit 1 provided in the embodiment of the present application, since the switch-type filter circuit 6 is turned on only when the voltage signal output by the dimmer switch is greater than the preset voltage, when the first signal jumps to the second signal, even if there is a sawtooth-shaped signal of high and low levels in the middle, and the voltage corresponding to the high level appearing in the sawtooth is not higher than the preset voltage, the switch-type filter circuit 6 is turned off, and the controller still collects the second signal. Therefore, the switch-type filter circuit 6 will not be on and off, and thus the controller will not mistakenly collect the first signal as the second signal, nor will it mistakenly collect the second signal as the first signal, thereby overcoming the screen flickering caused by the sawtooth-shaped slow-fall curve of the falling edge of the dimmer switch output signal, thereby improving the user experience.

[0107] Figure 4 for Figure 3 The circuit diagram of the dimming signal acquisition circuit in the instrument circuit of the vehicle shown in FIG. 1 is a circuit diagram of the dimming signal acquisition circuit in the instrument circuit of the vehicle shown in FIG. 1 . In an optional embodiment, as shown in FIG. 1 , Figure 4 As shown, the switch type filter circuit 6 includes a first transistor Q1.

[0108] The base of the first transistor Q1 is connected between the first voltage-dividing resistor R50 and the second voltage-dividing resistor R51, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is respectively connected to the DC power supply terminal and the control unit 7. It can be understood that the base of the first transistor Q1 serves as the first connection terminal of the switch type filter circuit 6, and the collector serves as the second connection terminal of the switch type filter circuit 6.

[0109] In a specific embodiment, when the output voltage of the dimming switch circuit 3 is greater than the preset voltage, the first transistor Q1 is turned on, and at this time, the single-chip microcomputer collects a low level at the ground terminal. If the output voltage of the dimming switch circuit 3 is not greater than the preset voltage, the first transistor Q1 is turned off, and at this time, the single-chip microcomputer collects a high level at the DC power supply terminal. Since the low level is collected when it is turned on, and the high level is collected when it is turned off, which is exactly the opposite of adjusting the brightness of the display screen, the control unit 7 needs to invert the collected voltage signal, that is, invert the low level collected when it is turned on to a high level, and invert the high level collected when it is turned off to a low level. That is to say, at this time, the first signal collected by the control unit 7 is a high-level signal after inversion, and the second signal is a low-level signal after inversion.

[0110] For example, when the output voltage of the dimming switch circuit 3 is greater than 4.2V, the first transistor Q1 is turned on, and the control unit 7 collects a low-level signal (0V). When the output voltage is not greater than 4.2V, the first transistor Q1 is turned off, and the control unit 7 collects a high-level signal (3.3V). Since the output voltage and the voltage collected by the notification unit have opposite polarities, the control unit 7 performs an inversion process, inverting the low-level signal into a high-level signal, and inverting the high-level signal into a low-level signal.

[0111] It can be understood that when the first transistor Q1 is turned on, the first signal collected by the control unit 7 is a high level, and when the first transistor Q1 is turned off, the second signal collected by the control unit 7 is a low level. In the process of jumping from a high level to a low level, even if a sawtooth mutation signal appears, the mutation high level will not be greater than the preset voltage. Therefore, the control unit 7 still collects a low level signal, thereby avoiding collecting disordered signals in the process of jumping from a high level to a low level, causing the instrument display screen 2 to flash.

[0112] In an optional embodiment, in order to further ensure the accuracy of the signal collected by the control unit 7, as Figure 4 As shown, the switch type filter circuit 6 also includes: a first filter capacitor C1, which is connected between the base of the first transistor Q1 and the ground terminal. In a specific embodiment, the first filter capacitor C1 can filter smaller voltage fluctuations to improve signal acquisition accuracy.

[0113] On the basis of the first filter capacitor C1, in order to further improve the accuracy of signal acquisition, in another optional embodiment, as Figure 4 As shown, the switch type filter circuit 6 also includes: a second filter capacitor C2, the second filter capacitor C2 is connected between the collector of the first transistor Q1 and the ground terminal, and is used to filter the signal at the output end of the switch type filter circuit 6 again, further improving the accuracy of the signal collected by the control unit 7, thereby further reducing the risk of the instrument display screen 2 flashing.

[0114] In an optional embodiment, for the safety of the dimming signal acquisition circuit 4, as Figure 4 As shown, the switch type filter circuit 6 also includes: a first resistor R1 and a second resistor R2, the first resistor R1 is connected between the collector of the first transistor Q1 and the DC power supply, and the second resistor R2 is connected between the collector of the first transistor Q1 and the control unit 7.

[0115] In a specific embodiment, the first resistor R1 is a current limiting resistor of the first transistor Q1 to prevent the first transistor Q1 from short circuiting. The second resistor R2 is a current limiting resistor to limit the current entering the control unit 7, that is, to protect the connection terminal pin of the control unit 7.

[0116] In a specific embodiment, in addition to overcoming the screen flicker problem caused by the sawtooth-shaped slow-fall curve of the waveform falling edge of the output signal of the dimming switch circuit 3 from the perspective of the dimming signal acquisition circuit 4, the screen flicker problem can also be overcome starting from the dimming switch circuit 3. That is, the screen flicker problem can be solved from the signal transmission path, and can also be overcome from the signal source.

[0117] Figure 5 A circuit diagram of a dimming switch circuit provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, in the current dimming switch circuit, the resistor R100 and the capacitor C3 form an RC delay circuit in the dimming switch circuit. In a specific embodiment, the RC delay circuit is an electronic circuit that uses the interaction between a resistor and a capacitor to achieve signal delay.

[0118] Specifically, when the power supply voltage is turned on, capacitor C3 will be charged, and resistor R100 can control the charging rate of the capacitor. When capacitor C3 is charged to a certain voltage, charging will stop. Obviously, the charging time of capacitor C3 is related to the combination of capacitor C3 and resistor R100. When the resistance value of resistor R100 increases, the charging time of capacitor C3 will increase.

[0119] In the specific implementation, there is a delay phenomenon in the rise and fall of the final output voltage of the RC delay circuit, that is, the rising and falling waveforms are smooth and sawtooth-shaped, that is, the RC delay circuit will eventually cause the falling edge of the waveform of the output signal of the dimming switch circuit 3 to present a sawtooth-shaped slow-fall curve, which in turn leads to the risk of screen flickering on the instrument display screen 2. The larger the resistance value of the resistor R100, the longer the charging time of the capacitor C3, the smoother the waveform of the final output signal, and the greater the risk of screen flickering.

[0120] In addition, when transistor Q4 is turned on, capacitor C3 will charge quickly, and the rising edge is steeper than the falling edge. After transistor Q4 is turned off, capacitor C3 needs to discharge. Since capacitor C3 has no discharge loop to the ground, the discharge is slow, which causes the falling edge curve to drop slowly, and the risk of a sawtooth curve increases.

[0121] Figure 6 for Figure 3 The circuit diagram of the dimming switch circuit in the instrument circuit of the vehicle shown in the figure is to solve the above technical problems, such as Figure 6 As shown, the dimming switch circuit 3 provided in the embodiment of the present application includes: a signal modulation circuit 8, a third resistor R3 and a discharge device 9, and the third resistor R3 is a zero-ohm resistor. One end of the third resistor R3 is connected to the signal modulation circuit 8, and the other end of the third resistor R3 is respectively connected to one end of the discharge device 9 and the voltage divider circuit 5, and the other end of the discharge device 9 is grounded.

[0122] The third resistor R3 is set to a zero ohm resistor, which shortens the discharge time of the discharge device 9, makes the falling edge of the signal steep, and eliminates the risk of high and low level interleaving, that is, eliminates the interference problem caused by the smooth rise and fall of the voltage caused by charging and discharging.

[0123] Therefore, the vehicle instrument circuit 1 provided in the embodiment of the present application sets the third resistor R3 to a zero-ohm resistor, thereby eliminating the problem of a smooth rise and fall of the voltage caused by capacitor storage and release, which in turn leads to a sawtooth curve, and ensuring that there is no sawtooth in the process from high level to low level. The waveform becomes standard, and there is no longer a fluctuating high and low level state interlacing phenomenon. The dimming signal acquisition circuit 4 will not collect disordered high and low level signals, and will not arbitrarily adjust the brightness of the screen suddenly, ultimately avoiding the occurrence of screen flickering.

[0124] In an optional embodiment, the discharge device 9 may be a third capacitor. In another optional embodiment, the discharge device 9 may be a fourth resistor R4. That is, the discharge device 9 may be a resistor or a capacitor.

[0125] In a specific embodiment, if the discharge device 9 is a third capacitor, since the third capacitor has no discharge circuit, the capacitance of the third capacitor needs to be reduced. In fact, even if the capacitance of the third capacitor is reduced, the falling edge of the signal is still not steep enough. Therefore, the discharge device 9 is preferably a resistor.

[0126] When the discharge device 9 is the fourth resistor R4, if the resistance of the fourth resistor R4 is too small, the load becomes larger and excess power consumption is generated. If the resistance of the fourth resistor R4 is too large, the falling edge of the signal is not steep enough, that is, the elimination of the jagged curve is not obvious enough. Therefore, in a specific embodiment, the resistance of the fourth resistor R4 needs to be set according to the specific circuit or according to multiple groups of test results.

[0127] In addition, it is worth noting that when the discharge device 9 is the fourth resistor R4, the third resistor R3 and the fourth resistor R4 form a voltage divider circuit 5, but because the third resistor R3 is a zero-ohm resistor, the influence of the voltage divider on the signal can be eliminated.

[0128] like Figure 6 As shown, the signal modulation circuit 8 for converting a low-frequency signal into a high-frequency PWM signal with a variable pulse width includes: an inverter D, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12, a fourth capacitor C4 and a fifth capacitor C5.

[0129] The inverter D is connected to the base of the second triode Q2, the emitter of the second triode Q2 and the emitter of the third triode Q3 are grounded, the collector of the third triode Q3 is connected to the base of the second triode Q2, and the collector of the second triode Q2 is connected to the base of the fourth triode Q4;

[0130] The base of the third triode Q3 is connected to the collector of the fifth triode Q5, the collector of the fourth triode Q4 is connected to the third resistor R3, the emitter of the fourth triode Q4 is connected to the base of the fifth triode Q5, and the emitter and base of the fifth triode Q5 are both connected to the DC power supply.

[0131] The fifth resistor R5 and the sixth resistor R6 are connected in series, and the other end of the fifth resistor R5 is connected to the inverter D, and the other end of the sixth resistor R6 is connected to the base of the second transistor Q2.

[0132] The seventh resistor R7 is connected between the base of the second triode Q2 and the emitter of the second triode Q2, the eighth resistor R8 is connected between the base of the third triode Q3 and the collector of the fifth triode Q5, and the ninth resistor R9 is connected between the collector of the second triode Q2 and the base of the fourth triode Q4;

[0133] The tenth resistor R10 is connected between the base and the emitter of the fourth transistor Q4 , the eleventh resistor R11 and the twelfth resistor R12 are connected in parallel, and both the eleventh resistor R11 and the twelfth resistor R12 are connected between the emitter and the base of the fifth transistor Q5 .

[0134] One end of the fourth capacitor C4 is connected to the common end of the fifth resistor R5 and the sixth resistor R6 connected in series, and the other end of the fourth capacitor C4 is grounded. One end of the fifth capacitor C5 is connected to the emitter of the fifth transistor Q5, and the other end of the fifth capacitor C5 is grounded.

[0135] Certain features described in multiple embodiments within this specification may also be implemented in combination in a single embodiment. On the other hand, various features described in a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although features may function in certain combinations as described above and may even be initially claimed as such, one or more features from a claimed combination may be removed from the combination in some cases, and a claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0136] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring that these operations be performed in the particular order shown or performed sequentially, or requiring that all illustrated operations be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system modules and components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product, or packaged into multiple software products.

[0137] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous.

[0138] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An instrument circuit of a vehicle, characterized in that: The instrument circuit is used to connect to the instrument display screen to adjust the brightness of the instrument display screen. The instrument circuit includes: A dimming switch circuit, used to output a voltage signal for adjusting the brightness of the instrument display screen; A dimming signal acquisition circuit, comprising: a voltage divider circuit, a switch type filter circuit and a control unit; The voltage divider circuit is connected between the dimming switch circuit and the switch type filter circuit, and the switch type filter circuit is connected between the voltage divider circuit and the control unit; The switching filter circuit is turned on when the voltage signal is greater than a preset voltage, and the control unit receives a first signal; the switching filter circuit is turned off when the voltage signal is not greater than the preset voltage, and the control unit receives a second signal; the control unit is connected to the instrument display screen, and is used to adjust the brightness of the instrument display screen according to the first signal and the second signal.

2. The vehicle instrument circuit according to claim 1, characterized in that: The voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor connected in series between the dimming switch circuit and a ground terminal; The switch type filter circuit comprises a first connection end and a second connection end, wherein the first connection end is connected between the first voltage dividing resistor and the second voltage dividing resistor; The control unit is connected to the second connection end.

3. The vehicle instrument circuit according to claim 2, characterized in that: The switch type filter circuit comprises a first transistor; The base of the first transistor is connected between the first voltage-dividing resistor and the second voltage-dividing resistor, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to the DC power supply terminal and the control unit respectively.

4. The vehicle instrument circuit according to claim 3, characterized in that: The switch type filter circuit further comprises: a first filter capacitor and a second filter capacitor; The first filter capacitor is connected between the base of the first transistor and the ground terminal, and the second filter capacitor is connected between the collector of the first transistor and the ground terminal.

5. The vehicle instrument circuit according to claim 3, characterized in that: The switch type filter circuit further includes: a first resistor; The first resistor is connected between the collector of the first transistor and the DC power supply.

6. The vehicle instrument circuit according to claim 3, characterized in that: The switch type filter circuit further includes: a second resistor; The second resistor is connected between the collector of the first transistor and the control unit.

7. The vehicle instrument circuit according to claim 1, characterized in that: The dimming switch circuit comprises: a signal modulation circuit, a third resistor and a discharge device, and the third resistor is a zero-ohm resistor; The signal modulation circuit is used to convert the low-frequency signal into a high-frequency PWM signal with a variable pulse width; One end of the third resistor is connected to the signal modulation circuit, the other end of the third resistor is respectively connected to one end of the discharge device and the voltage divider circuit, and the other end of the discharge device is grounded.

8. The vehicle instrument circuit according to claim 7, characterized in that: The discharge device includes a fourth resistor.

9. The vehicle instrument circuit according to claim 7, characterized in that: The discharge device includes a third capacitor.

10. A vehicle, characterized in that: The invention comprises an instrument display screen and an instrument circuit of a vehicle as claimed in any one of claims 1 to 9, wherein the instrument circuit is connected to the instrument display screen and is used to adjust the brightness of the instrument display screen.

Images