A smart panel button backlight control system and method

Abstract

The present invention relates to the technical field of smart panels, and provides a smart panel key backlight control system and method, including: a backlight switching device, a key backlight off master control device, a key operation device and a backlight main control chip; the backlight switching device includes: a key on indicator light module, a key off indicator light module, a light power supply, a first on-off module, a second on-off module and a shunt resistor; the key backlight off master control device includes: a third on-off module and a master control point; the key signal IO pin of the backlight main control chip is connected to the key operation device. The beneficial effects of the technical solution of the present invention are: in a smart panel with a key dual-color backlight requirement, the number of IO pins of the backlight main control chip occupied by the indicator light module is reduced, and a single backlight main control chip can be provided with a larger number of keys with dual-color backlight functions, effectively avoiding the high cost caused by adding an expansion chip and the space of the circuit board occupied by the expansion chip when the IO pins of the backlight main control chip are insufficient.

Description

Technical Field

[0001] The present invention relates to the technical field of smart panels, and in particular to a smart panel key backlight control system and method. Background Art

[0002] Smart panels are operating panels used in smart homes, such as those used to control room air conditioners and ceiling lights. Currently, people have more and more functional requirements for smart panels, requiring the buttons of smart panels to have dual-color backlights as indicator lights for the "on / off" of the buttons, and requiring the brightness of the two colors to be adjusted separately. For example, when a button on a smart panel is in the on state, the backlight of this button is white, and when this button is in the off state, the backlight of this button is yellow; the button has a purpose character, and the button backlight helps users to see the character content more easily and confirm the button position and switch status of home appliances; for example, the character of a button is "air conditioning", when the user sees that the backlight of this button is white, the user knows that this button is in the on state and the air conditioner is started; when the user sees that the backlight of this button is yellow, the user knows that this button is in the off state and the air conditioner is turned off.

[0003] Traditional dual-color backlight smart panel, combined with Figure 1 , the indicator light of a key operation device 3 needs to occupy two IO pins of the backlight main control chip 4, that is, one IO pin of the backlight main control chip 4 is set to the key-on indicator light module 11, and the other IO pin is set to the key-off indicator light module 12; the IO pin is the signal input and output pin of the backlight main control chip. For a multi-button smart panel, since the IO pins of the backlight main control chip occupied by the indicator light module are twice the number of buttons, the number of IO pins of the backlight main control chip occupied by the indicator light module is increasing, and it is easy to have insufficient IO pins of the backlight main control chip. The traditional solution is to add an expansion chip, but it will increase the cost of the expansion chip and the expansion chip will increase the space occupied by the circuit board.

[0004] Therefore, how to reduce the number of IO pins of the backlight main control chip occupied by the indicator light module in the smart panel with dual-color backlight requirements for keys is a technical problem that needs to be solved urgently in the current technical field. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a smart panel key backlight control system and method, which reduces the number of IO pins of the backlight main control chip occupied by the indicator light module in the smart panel with dual-color backlight requirements for keys.

[0006] The present invention is implemented as follows: an intelligent panel key backlight control system, comprising:

[0007] Backlight switching device, key-off backlight master control device, key operation device and backlight main control chip;

[0008] The backlight switching device comprises: a button-on indicator light module, a button-off indicator light module, a light power supply, a first on-off module, a second on-off module and a shunt resistor;

[0009] The key-operated backlight control device comprises: a third on-off module and a master control point;

[0010] The switching signal IO pin of the backlight main control chip is connected to the control end of the first on-off module, the signal input end of the first on-off module is connected to one end of the button-on indicator light module, the signal output end of the first on-off module is grounded, the other end of the button-on indicator light module is connected to the light power supply, one end of the shunt resistor is connected to one end of the button-on indicator light module, the other end of the shunt resistor is connected to the light power supply, the control end of the second on-off module is connected to one end of the shunt resistor, the signal input end of the second on-off module is connected to one end of the button-off indicator light module, the signal output end of the second on-off module is connected to the main control point, and the other end of the button-off indicator light module is connected to the light power supply;

[0011] The main off signal IO pin of the backlight main control chip is connected to the control end of the third on-off module, the signal input end of the third on-off module is connected to the main control point, and the signal output end of the third on-off module is grounded;

[0012] The key signal IO pin of the backlight main control chip is connected to the key operation device.

[0013] Further, the first on-off module includes: a first NPN transistor and a first resistor, the base of the first NPN transistor is connected to one end of the first resistor, the collector of the first NPN transistor is connected to one end of the button-on indicator light module, the emitter of the first NPN transistor is grounded, and the other end of the first resistor is connected to the switching signal IO pin of the backlight main control chip;

[0014] The second on-off module includes: a second NPN transistor and a second resistor, the base of the second NPN transistor is connected to one end of the second resistor, the collector of the second NPN transistor is connected to one end of the key-off indicator light module, the emitter of the second NPN transistor is connected to the main control point, and the other end of the second resistor is connected to one end of the shunt resistor;

[0015] The third on-off module includes: a third NPN transistor and a third resistor, the base of the third NPN transistor is connected to one end of the third resistor, the collector of the third NPN transistor is connected to the main control point, the emitter of the third NPN transistor is grounded, and the other end of the third resistor is connected to the main off signal IO pin of the backlight main control chip.

[0016] Further, the button-on indicator light module comprises: a first color light emitting diode and a first current limiting resistor, one end of the first current limiting resistor is connected to the collector of the first NPN transistor, the other end of the first current limiting resistor is connected to the cathode of the first color light emitting diode, and the anode of the first color light emitting diode is connected to the lamp power supply;

[0017] The button-off indicator light module includes: a second color light-emitting diode and a second current-limiting resistor, one end of the second current-limiting resistor is connected to the collector of the second NPN transistor, the other end of the second current-limiting resistor is connected to the cathode of the second color light-emitting diode, and the anode of the second color light-emitting diode is connected to the lamp power supply.

[0018] Furthermore, the first color light emitting diode emits white light, and the second color light emitting diode emits yellow light.

[0019] Furthermore, the key operation device includes: a key, a pull-up resistor, a de-jitter capacitor and a key power supply, one end of the key is connected to the key signal IO pin of the backlight main control chip, the other end of the key is grounded, one end of the pull-up resistor is connected to one end of the key, the other end of the pull-up resistor is connected to the key power supply, one end of the de-jitter capacitor is connected to one end of the key, and the other end of the de-jitter capacitor is grounded.

[0020] Furthermore, the backlight main control chip is an MCU.

[0021] Furthermore, there are more than two of the button-on indicator light modules and the button-off indicator light modules, and they are arranged at intervals on the back of the button operation device.

[0022] Furthermore, there are more than two key operating devices, each of which is configured with a backlight switching device, the number of switching signal IO pins of the backlight master control chip is equal to the number of the key operating devices, the number of the key-off backlight master control device is one, and the number of the master-off signal IO pins of the backlight master control chip is equal to the number of the key-off backlight master control devices.

[0023] A method for controlling backlight of a key on a smart panel, using the above-mentioned backlight control system of a key on a smart panel, comprises:

[0024] When the key of the key operation device is pressed, the backlight main control chip sends a key-on signal to the backlight switching device, the backlight switching device corresponds to the key operation device, the backlight main control chip also sends a key-off indicator light master control light signal to the key-off backlight master control device, the first on-off module becomes on, the key-on indicator light module lights up, the second on-off module becomes off, the key-off indicator light module goes out, and the third on-off module is in on;

[0025] When the button of the button operation device is pressed again, the backlight main control chip sends the button off signal to the backlight switching device, and the backlight main control chip also sends the button off indicator light master control signal to the button off backlight master control device, the first on-off module becomes disconnected, the button on indicator light module goes out, the second on-off module becomes conductive, the third on-off module is in conductive state, and the button off indicator light module lights up.

[0026] Further, the key-on signal is a first PWM signal, the key-off indicator light master control lighting signal is a second PWM signal, the key-off signal is a low-level signal, the starting waveform of the first PWM signal is consistent with the starting waveform of the second PWM signal, and the duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal.

[0027] Compared with the background technology, the technical solution of the present invention has the following beneficial effects:

[0028] 1. The button-on indicator light module and the button-off indicator light module are uniformly set on the switching signal IO pin of the backlight main control chip by the backlight switching device, so that the button-on indicator light module and the button-off indicator light module are controlled by one IO pin of the backlight main control chip, and the lighting states of the button-on indicator light module and the button-off indicator light module corresponding to one button are mutually exclusive; the additional button-off backlight master control device occupies one IO pin of the backlight main control chip, namely the master off signal IO pin, which is used to master the lighting states of all button-off indicator light modules; in the smart panel with the requirement of dual-color backlight for buttons, the number of IO pins of the backlight main control chip occupied by the indicator light module is reduced, and a single backlight main control chip can be used to set more buttons with dual-color backlight functions in the smart panel, effectively avoiding the high cost caused by adding expansion chips and the space occupied by expansion chips on the circuit board when the IO pins of the backlight main control chip are insufficient.

[0029] 2. The first PWM signal sent by the backlight main control chip is used to adjust the brightness of the button-on indicator light module; the second PWM signal sent is used to adjust the brightness of the button-off indicator light module to meet the demand for individually adjusting the button backlight brightness of the smart panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0031] Figure 1 The diagram is a schematic diagram of key connections of a conventional smart panel for realizing dual-color backlight in the background art.

[0032] Figure 2 The invention discloses a structural schematic diagram of a smart panel key backlight control system.

[0033] Figure 3 It is a circuit diagram of the backlight switching device in the present invention.

[0034] Figure 4 It is a circuit diagram of the key-turn-off backlight master control device in the present invention.

[0035] Figure 5 It is a circuit diagram of the key operation device in the present invention.

[0036] Figure 6 It is a waveform diagram showing that the duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal in the present invention. DETAILED DESCRIPTION

[0037] The embodiment of the present invention provides a smart panel key backlight control system and method, and the overall idea of ​​the technical solution is as follows:

[0038] A button of the smart panel is configured with a backlight switching device. When the power is turned on, in the backlight switching device, the lighting states of the button-on indicator light module and the button-off indicator light module are mutually exclusive. When the button-on indicator light module is lit, the button-off indicator light module is off. When the button-on indicator light module is off, the button-off indicator light module is lit.

[0039] A backlight switching device occupies one IO pin of the backlight main control chip, and realizes controlling the button-on indicator light module and the button-off indicator light module by one IO pin of the backlight main control chip. For multiple buttons of the smart panel, compared with the background technology, two IO pins are required to respectively set the button-on indicator light module and the button-off indicator light module. The indicator light module of the present invention occupies fewer IO pins of the backlight main control chip.

[0040] The luminous brightness of the key-on indicator light module and the key-off indicator light module can be adjusted separately; when a key of the smart panel is in the on state, the key operating device where the key is located sends a signal to the backlight main control chip, the backlight main control chip sends a first PWM signal to the corresponding backlight switching device, the key-on indicator light module corresponding to the key is illuminated, the brightness of the light is determined by the duty cycle of the first PWM signal, and the key-off indicator light module corresponding to the key is extinguished; the backlight main control chip simultaneously sends a second PWM signal to the key-off backlight master control device, the other keys of the smart panel are in the off state, the key operating devices where the other keys are located send a signal to the backlight main control chip, the backlight main control chip sends a continuous low-level signal to the corresponding backlight switching device, so that the key-on indicator light modules corresponding to the other keys are extinguished, but the key-off indicator light modules are illuminated, and the brightness of the light emitted by all the key-off indicator light modules is determined by the duty cycle of the second PWM signal.

[0041] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] See also Figures 1 to 6 , a preferred embodiment of the present invention.

[0043] An intelligent panel button backlight control system, comprising:

[0044] Backlight switching device 1, key-off backlight master control device 2, key operation device 3 and backlight main control chip 4;

[0045] The backlight switching device 1 comprises: a button-on indicator light module 11, a button-off indicator light module 12, a light power supply, a first on-off module 13, a second on-off module 14 and a shunt resistor R0;

[0046] The key-turn-off backlight master control device 2 comprises: a third on-off module 21 and a master control point P;

[0047] The switching signal IO pin 41 of the backlight main control chip 4 is connected to the control end of the first on-off module 13, the signal input end of the first on-off module 13 is connected to one end of the button-on indicator light module 11, the signal output end of the first on-off module 13 is grounded, the other end of the button-on indicator light module 11 is connected to the light power supply, one end of the shunt resistor R0 is connected to one end of the button-on indicator light module 11, the other end of the shunt resistor R0 is connected to the light power supply, the control end of the second on-off module 14 is connected to one end of the shunt resistor R0, the signal input end of the second on-off module 14 is connected to one end of the button-off indicator light module 12, the signal output end of the second on-off module 14 is connected to the main control point P, and the other end of the button-off indicator light module 12 is connected to the light power supply;

[0048] The total off signal IO pin 42 of the backlight main control chip 4 is connected to the control end of the third on-off module 21, the signal input end of the third on-off module 21 is connected to the total control point P, and the signal output end of the third on-off module 21 is grounded;

[0049] The key signal IO pin 43 of the backlight main control chip 4 is connected to the key operation device 3 .

[0050] The beneficial effects of the technical solution of the present invention are as follows: the button-on indicator light module 11 and the button-off indicator light module 12 are uniformly set by the backlight switching device 1 at the switching signal IO pin 41 of the backlight main control chip 4, so that the button-on indicator light module 11 and the button-off indicator light module 12 are controlled by one IO pin of the backlight main control chip 4, and the luminous states of the button-on indicator light module 11 and the button-off indicator light module 12 corresponding to one button are mutually exclusive; the additional button-off backlight master control device 2 occupies one IO pin of the backlight main control chip 4, namely, the master-off signal IO pin 42, which is used to master the luminous states of all button-off indicator light modules 12; in the smart panel with the requirement of dual-color backlight for buttons, the number of IO pins of the backlight main control chip 4 occupied by the indicator light module is reduced, and a single backlight main control chip 4 can be used to set more buttons with dual-color backlight functions in the smart panel, effectively avoiding the high cost caused by adding an expansion chip and the space occupied by the expansion chip on the circuit board when the IO pins of the backlight main control chip are insufficient.

[0051] In the background technology, the expansion chip is specifically a GPIO expansion chip, and the backlight main control chip is an MCU. When the IO pins of the MCU are insufficient, a GPIO expansion chip is added to increase the number of IO pins. However, the technical idea of ​​the present invention is to reduce the number of IO pins occupied by the indicator light module of the backlight main control chip in the smart panel with the requirement of dual-color backlight for keys, so that a single backlight main control chip can be provided with more keys with dual-color backlight function.

[0052] The on-off module can be a device with a switch function such as a triode, a MOS tube, etc. The light colors of the key-on indicator light module 11 and the key-off indicator light module 12 are different. The power supply for the lamp is +5V.

[0053] Further, the first on-off module 13 includes: a first NPN transistor Q1 and a first resistor R1, the base of the first NPN transistor Q1 is connected to one end of the first resistor R1, the collector of the first NPN transistor Q1 is connected to one end of the key-on indicator light module 11, the emitter of the first NPN transistor Q1 is grounded, and the other end of the first resistor R1 is connected to the switching signal IO pin 41 of the backlight main control chip 4;

[0054] The second on-off module 14 includes: a second NPN transistor Q2 and a second resistor R2, the base of the second NPN transistor Q2 is connected to one end of the second resistor R2, the collector of the second NPN transistor Q2 is connected to one end of the key-off indicator light module 12, the emitter of the second NPN transistor Q2 is connected to the main control point P, and the other end of the second resistor R2 is connected to one end of the shunt resistor R0;

[0055] The third on-off module 21 includes: a third NPN transistor Q3 and a third resistor R3, the base of the third NPN transistor Q3 is connected to one end of the third resistor R3, the collector of the third NPN transistor Q3 is connected to the main control point P, the emitter of the third NPN transistor Q3 is grounded, and the other end of the third resistor R3 is connected to the main off signal IO pin 42 of the backlight main control chip 4.

[0056] The working principle of the NPN transistor as a switch is that when the base is at a high level, the collector and emitter are turned on, and when the base is at a low level, the collector and emitter are turned off.

[0057] Furthermore, the button-on indicator light module 11 comprises: a first color light-emitting diode LED1 and a first current-limiting resistor R10, one end of the first current-limiting resistor R10 is connected to the collector of the first NPN transistor Q1, the other end of the first current-limiting resistor R10 is connected to the cathode of the first color light-emitting diode LED1, and the anode of the first color light-emitting diode LED1 is connected to the lamp power supply;

[0058] The button off indicator light module 12 includes: a second color light emitting diode LED2 and a second current limiting resistor R20, one end of the second current limiting resistor R20 is connected to the collector of the second NPN transistor Q2, the other end of the second current limiting resistor R20 is connected to the cathode of the second color light emitting diode LED2, and the anode of the second color light emitting diode LED2 is connected to the lamp power supply.

[0059] Light emitting diodes have the advantages of energy saving and long service life.

[0060] Furthermore, the first color light emitting diode LED1 emits white light, and the second color light emitting diode LED2 emits yellow light.

[0061] The light emitting colors of the first color light emitting diode LED1 and the second color light emitting diode LED2 may be a combination of other different colors.

[0062] Furthermore, the key operation device 3 includes: a key SW1, a pull-up resistor R30, a de-jitter capacitor C1 and a key power supply, one end of the key SW1 is connected to the key signal IO pin 43 of the backlight main control chip 4, the other end of the key SW1 is grounded, one end of the pull-up resistor R30 is connected to one end of the key SW1, the other end of the pull-up resistor R30 is connected to the key power supply, one end of the de-jitter capacitor C1 is connected to one end of the key SW1, and the other end of the de-jitter capacitor C1 is grounded.

[0063] When the key SW1 is closed, the de-bouncing capacitor C1 is discharged, the key signal IO pin 43 of the backlight main control chip 4 is at a low level, and the backlight main control chip 4 receives a signal that the key SW1 is in the off state; when the key SW1 is disconnected, the key power supply quickly charges the de-bouncing capacitor C1. After the de-bouncing capacitor C1 is charged, the key signal IO pin 43 of the backlight main control chip 4 is at a high level, and the backlight main control chip 4 receives a signal that the key SW1 is in the on state; the key power supply is +3.3V.

[0064] When a key is pressed, the key may vibrate due to mechanical vibration, causing the backlight main control chip to misjudge the key status. By connecting a de-jitter capacitor in parallel to the key circuit, the characteristic that the voltage of the capacitor cannot change suddenly can be used. When the key is released, the capacitor will charge slowly, thus preventing false touches caused by key jitter.

[0065] Furthermore, the backlight main control chip 4 is an MCU.

[0066] Furthermore, there are more than two button-on indicator light modules 11 and button-off indicator light modules 12, and they are arranged at intervals on the back of the button operation device 3, so as to more clearly display the backlight of the button and facilitate user identification.

[0067] Furthermore, there are more than two key operating devices 3, each of the key operating devices 3 is configured with a backlight switching device 1, the number of switching signal IO pins 41 of the backlight main control chip 4 is equal to the number of the key operating devices 3, the number of the key-off backlight master control device 2 is one, and the number of the master-off signal IO pins 42 of the backlight main control chip 4 is equal to the number of the key-off backlight master control devices 2.

[0068] For example, the smart panel has six buttons. In the present invention, there are six button operating devices 3, six button signal IO pins 43 of the backlight main control chip 4, six backlight switching devices 1, six switching signal IO pins 41 of the backlight main control chip 4, only one button to turn off the backlight master control device 2, and one master off signal IO pin 42 of the backlight master control chip 4. Therefore, the number of IO pins of the backlight master control chip 4 occupied by the present invention is thirteen.

[0069] In comparison, in the background technology, in the traditional smart panel that realizes dual-color backlight, the button operation device 3 occupies six IO pins of the backlight main control chip, the button on indicator light module 11 occupies six IO pins of the backlight main control chip 4, and the button off indicator light module 12 occupies six IO pins of the backlight main control chip 4. The total number of IO pins of the backlight main control chip 4 occupied is eighteen.

[0070] A method for controlling backlight of a key on a smart panel, using the above-mentioned backlight control system of a key on a smart panel, comprises:

[0071] When the button of the button operation device 3 is pressed, the backlight main control chip 4 sends the button-on signal to the backlight switching device 1, and the backlight switching device 1 corresponds to the button operation device 3. The backlight main control chip 4 also sends the button-off indicator light master control light signal to the button-off backlight master control device 2, and the first on-off module 13 becomes the on state, the button-on indicator light module 11 lights up, the second on-off module 14 becomes the off state, the button-off indicator light module 12 goes out, and the third on-off module 21 is in the on state;

[0072] When the button of the button operation device 3 is pressed again, the backlight main control chip 4 sends the button off signal to the backlight switching device 1, and the backlight main control chip 4 also sends the button off indicator light master control signal to the button off backlight master control device 2, the first on-off module 13 becomes disconnected, the button on indicator light module 11 goes out, the second on-off module 14 becomes on, the third on-off module 21 is in the on state, and the button off indicator light module 12 lights up.

[0073] When the button of the button operation device 3 is a self-locking button, the button is pressed and the button is in the on state, and the backlight main control chip 4 sends a button on signal to the backlight switching device 1; the button is pressed again and the button becomes off, and the backlight main control chip 4 sends a button off signal to the backlight switching device 1.

[0074] When the key of the key operation device 3 is lightly touched, each pressing of the key will generate a level signal and send it to the backlight main control chip 4. The backlight main control chip 4 alternately sends a key-on signal and a key-off signal to the backlight switching device 1.

[0075] In the case where there is no need to adjust the brightness of the indicator light, when the button of the button operation device 3 is in the on state, the backlight main control chip 4 sends a high-level signal to the corresponding backlight switching device 1, and at the same time sends a high level to the button-off backlight master control device 2, the base of the first NPN transistor Q1 is at a high level, the first NPN transistor Q1 is turned on, the first color light emitting diode LED1 is powered on and emits white light, the base of the second NPN transistor Q2 is at a low level, the second NPN transistor Q2 is turned off, the second color light emitting diode LED2 is powered off and extinguished, the base of the third NPN transistor Q3 is at a high level, and the third NPN transistor Q3 remains in the on state.

[0076] When the button of the button operation device 3 is in the off state, the backlight main control chip 4 sends a low level signal to the corresponding backlight switching device 1, and at the same time sends a high level to the button off backlight master control device 2, the base of the first NPN transistor Q1 is at a low level, the first NPN transistor Q1 is cut off, the first color light emitting diode LED1 is powered off and extinguished, the base of the second NPN transistor Q2 becomes a high level, the second NPN transistor Q2 is turned on, the base of the third NPN transistor Q3 is at a high level, the third NPN transistor Q3 remains in the on state, and the second color light emitting diode LED2 is powered on to emit yellow light.

[0077] Further, the key-on signal is a first PWM signal, the key-off indicator light master control lighting signal is a second PWM signal, the key-off signal is a low-level signal, the starting waveform of the first PWM signal is consistent with the starting waveform of the second PWM signal, and the duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal.

[0078] The first PWM signal sent by the backlight main control chip 4 is used to adjust the brightness of the button-on indicator light module 11; the second PWM signal sent is used to adjust the brightness of the button-off indicator light module 12, meeting the demand for individually adjusting the button backlight brightness of the smart panel.

[0079] PWM signal is a pulse width modulation signal, which is a digital signal composed of high level and low level. The time ratio of the high level and the low level can be adjusted. The ratio of the high level time to the signal cycle is called the duty cycle. In the present invention, the higher the duty cycle of the PWM signal, the higher the brightness of the indicator light, and the smaller the duty cycle of the PWM signal, the dimmer the brightness of the indicator light.

[0080] The duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal, that is, when the first PWM signal is at a high level, the second PWM signal can be a high level or a low level, and when the first PWM signal is at a low level, the second PWM signal must be a low level.

[0081] For example, the smart panel has six buttons. When the first button is in the on state and the other buttons are in the off state, the backlight main control chip 4 sends the first PWM signal to the backlight switching device 1 corresponding to the first button, sends the low-level signal to the backlight switching device 1 corresponding to the other buttons, and sends the second PWM signal to the key-off backlight master control device 2; the first color light-emitting diode LED1 corresponding to the first button emits white light, and the second color light-emitting diode LED2 is off; the first color light-emitting diode LED1 corresponding to the other buttons is off, and the second color light-emitting diode LED2 emits yellow light. When the first button is in the off state, the backlight main control chip 4 sends the low-level signal to the backlight switching device 1 corresponding to the first button, the first color light-emitting diode LED1 corresponding to the first button is off, and the second color light-emitting diode LED2 emits yellow light.

[0082] The duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal. Specifically, when the duty cycle of the first PWM signal is 100%, the luminous height of the first color light emitting diode LED1 is the largest, the duty cycle of the second PWM signal can be freely adjusted between 0-100%, and the luminous brightness adjustment range of the second color light emitting diode LED2 reaches the maximum; when the duty cycle of the first PWM signal is 50%, the luminous brightness of the first color light emitting diode LED1 is halved, the duty cycle of the second PWM signal can be freely adjusted between 0-50%, and the luminous brightness adjustment range of the second color light emitting diode LED2 is halved; when the duty cycle of the first PWM signal is 20%, the luminous brightness of the first color light emitting diode LED1 is further reduced, the duty cycle of the second PWM signal can be freely adjusted between 0-20%, and the luminous brightness adjustment range of the second color light emitting diode LED2 is further reduced. When the duty cycle of the second PWM signal is fixed at 20%, the duty cycle of the first PWM signal can vary between 20-100%. Independent dimming of the first color light emitting diode LED1 and the second color light emitting diode LED2 is achieved.

[0083] The key backlight is fully turned on, so that the user can see the key characters more clearly. At this time, the brightness of the key-on indicator light module 11 and the key-off indicator light module 12 reaches the maximum, and the duty cycle of the first PWM signal and the second PWM signal is 100%.

[0084] The key backlight is completely turned off, so that light-sensitive users can avoid the backlight interference of the smart panel and improve their sleep. At this time, the key-on indicator light module 11 and the key-off indicator light module 12 do not emit light, and the duty ratios of the first PWM signal and the second PWM signal are both 0%.

[0085] The key backlight is energy-saving, which can help users find the keys of the smart panel in a dark environment. At this time, the brightness of the key-on indicator light module 11 and the key-off indicator light module 12 is reduced, for example, the duty cycle of the first PWM signal and the second PWM signal are both 50%.

[0086] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A smart panel key backlight control system, characterized in that: include: Backlight switching device, key-off backlight master control device, key operation device and backlight main control chip; The backlight switching device comprises: a button-on indicator light module, a button-off indicator light module, a light power supply, a first on-off module, a second on-off module and a shunt resistor; The key-operated backlight control device comprises: a third on-off module and a master control point; The switching signal IO pin of the backlight main control chip is connected to the control end of the first on-off module, the signal input end of the first on-off module is connected to one end of the button-on indicator light module, the signal output end of the first on-off module is grounded, the other end of the button-on indicator light module is connected to the light power supply, one end of the shunt resistor is connected to one end of the button-on indicator light module, the other end of the shunt resistor is connected to the light power supply, the control end of the second on-off module is connected to one end of the shunt resistor, the signal input end of the second on-off module is connected to one end of the button-off indicator light module, the signal output end of the second on-off module is connected to the main control point, and the other end of the button-off indicator light module is connected to the light power supply; The main off signal IO pin of the backlight main control chip is connected to the control end of the third on-off module, the signal input end of the third on-off module is connected to the main control point, and the signal output end of the third on-off module is grounded; The key signal IO pin of the backlight main control chip is connected to the key operation device.

2. The smart panel key backlight control system according to claim 1, characterized in that: The first on-off module includes: a first NPN transistor and a first resistor, the base of the first NPN transistor is connected to one end of the first resistor, the collector of the first NPN transistor is connected to one end of the button-on indicator light module, the emitter of the first NPN transistor is grounded, and the other end of the first resistor is connected to the switching signal IO pin of the backlight main control chip; The second on-off module includes: a second NPN transistor and a second resistor, the base of the second NPN transistor is connected to one end of the second resistor, the collector of the second NPN transistor is connected to one end of the key-off indicator light module, the emitter of the second NPN transistor is connected to the main control point, and the other end of the second resistor is connected to one end of the shunt resistor; The third on-off module includes: a third NPN transistor and a third resistor, the base of the third NPN transistor is connected to one end of the third resistor, the collector of the third NPN transistor is connected to the main control point, the emitter of the third NPN transistor is grounded, and the other end of the third resistor is connected to the main off signal IO pin of the backlight main control chip.

3. The intelligent panel key backlight control system according to claim 2, characterized in that: The button-on indicator light module comprises: a first color light emitting diode and a first current limiting resistor, one end of the first current limiting resistor is connected to the collector of the first NPN transistor, the other end of the first current limiting resistor is connected to the cathode of the first color light emitting diode, and the anode of the first color light emitting diode is connected to the lamp power supply; The button-off indicator light module includes: a second color light-emitting diode and a second current-limiting resistor, one end of the second current-limiting resistor is connected to the collector of the second NPN transistor, the other end of the second current-limiting resistor is connected to the cathode of the second color light-emitting diode, and the anode of the second color light-emitting diode is connected to the lamp power supply.

4. The intelligent panel key backlight control system according to claim 3, characterized in that: The first color light emitting diode emits white light, and the second color light emitting diode emits yellow light.

5. The smart panel key backlight control system according to claim 1, characterized in that: The key operation device includes: a key, a pull-up resistor, a de-jitter capacitor and a key power supply, one end of the key is connected to the key signal IO pin of the backlight main control chip, the other end of the key is grounded, one end of the pull-up resistor is connected to one end of the key, the other end of the pull-up resistor is connected to the key power supply, one end of the de-jitter capacitor is connected to one end of the key, and the other end of the de-jitter capacitor is grounded.

6. The intelligent panel key backlight control system according to claim 1, characterized in that: The backlight main control chip is MCU.

7. The smart panel key backlight control system according to claim 1, characterized in that: There are more than two of the button-on indicator light modules and the button-off indicator light modules, and they are arranged at intervals on the back of the button operation device.

8. The smart panel key backlight control system according to claim 1, characterized in that: There are more than two key operation devices, each of which is configured with a backlight switching device, the number of switching signal IO pins of the backlight master control chip is equal to the number of the key operation devices, the number of key-off backlight master control devices is one, and the number of master-off signal IO pins of the backlight master control chip is equal to the number of key-off backlight master control devices.

9. A method for controlling backlight of a key of an intelligent panel, characterized in that: A smart panel key backlight control system according to any one of claims 1 to 8, comprising: When the key of the key operation device is pressed, the backlight main control chip sends a key-on signal to the backlight switching device, the backlight switching device corresponds to the key operation device, the backlight main control chip also sends a key-off indicator light master control light signal to the key-off backlight master control device, the first on-off module becomes on, the key-on indicator light module lights up, the second on-off module becomes off, the key-off indicator light module goes out, and the third on-off module is in on; When the button of the button operation device is pressed again, the backlight main control chip sends the button off signal to the backlight switching device, and the backlight main control chip also sends the button off indicator light master control signal to the button off backlight master control device, the first on-off module becomes disconnected, the button on indicator light module goes out, the second on-off module becomes conductive, the third on-off module is in conductive state, and the button off indicator light module lights up.

10. The method for controlling backlight of a key of a smart panel according to claim 9, characterized in that: The key-on signal is a first PWM signal, the key-off indicator light master control lighting signal is a second PWM signal, the key-off signal is a low-level signal, the starting waveform of the first PWM signal is consistent with the starting waveform of the second PWM signal, and the duty cycle of the second PWM signal is less than or equal to the duty cycle of the first PWM signal.

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