Control circuit for solving splash screen problem of LED backlight screen of infrared remote controller

Abstract

The utility model relates to the technical field of LED driving, in particular to a control circuit for solving splash of an LED backlight screen of an infrared remote controller. Comprising an MCU master control module; the key module is connected with the MCU main control module; the LED backlight driving module is connected with the MCU main control module; the infrared transmitting tube driving module is connected with the MCU main control module; and the power supply module is respectively connected with the MCU main control module, the key module, the LED backlight driving module and the infrared transmitting tube driving module and is used for providing working voltage. According to the utility model, the LED backlight screen is prevented from being lightened when the voltage of the battery jitters and jumps, so that the LED backlight screen is lightened under a relatively stable voltage condition, the problem of splash screen of the LED backlight screen during infrared code sending of the remote controller is effectively solved, and the power consumption of the remote controller is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of LED driving, in particular to a control circuit for solving the problem of screen flashing of an LED backlight screen of an infrared remote control. Background Art

[0002] At present, the LED backlight screen of an infrared remote control generally adopts a direct drive method, that is, a constant voltage is provided for the LED backlight screen to light up the LED backlight screen. That is, the positive electrode of the LED backlight screen is connected to the positive electrode of the power supply, the negative electrode is connected to the ordinary IO pin of the MCU, and a low level output is maintained; or the negative electrode of the LED backlight screen is connected to the negative electrode of the power supply, the positive electrode is connected to the ordinary IO pin of the MCU, and a high level output is maintained to light up the LED backlight screen. As Figure 1 The circuit shown is the first of the above methods.

[0003] In addition, the power supply method of the infrared remote control generally uses 2 to 3 dry batteries for power supply, the infrared emitting tube uses 38KHz PWM drive, and the LED backlight screen uses a direct drive method. The two work simultaneously. Also, due to the weak driving ability of the MCU, especially when the infrared emitting tube is working, the power consumption will increase sharply. Immediately before the infrared emitting tube works, the battery voltage will be sharply pulled down, and immediately after the infrared emitting tube finishes working, it will bounce back and be pulled up. The level fluctuation of the battery voltage, high and low, causes the LED backlight screen to flash when the infrared code is sent. Especially in a dark environment, the flashing problem is more obvious, seriously affecting the user experience. The waveform diagram during specific operation is as Figure 2 shown.

[0004] Therefore, it is necessary to propose a control circuit for solving the problem of screen flashing of the LED backlight screen of the infrared remote control to solve the problem of screen flashing of the LED backlight screen when the infrared remote control sends a code. Content of the Utility Model

[0005] The purpose of the utility model is to provide a control circuit for solving the problem of screen flashing of the LED backlight screen of the infrared remote control to solve the problem of screen flashing of the LED backlight screen when the infrared remote control sends a code.

[0006] To solve the above technical problems, the utility model provides a control circuit for solving the problem of screen flashing of the LED backlight screen of the infrared remote control, including:

[0007] MCU main control module;

[0008] Button module, connected to the MCU main control module;

[0009] LED backlight driving module, connected to the MCU main control module;

[0010] Infrared emitting tube driving module, connected to the MCU main control module;

[0011] A power supply module, which is respectively connected to the MCU main control module, the button module, the LED backlight driving module and the infrared emitting tube driving module, and is used to provide a working voltage.

[0012] Preferably, the LED backlight driving module includes: resistors R1 to R2, a triode Q1 and an LED backlight screen U2; one end of the resistor R1 is connected to PWM_LED, the other end is connected to the base of the triode Q1, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the GND terminal of the LED backlight screen U2, and the VCC terminal of the LED backlight screen U2 is connected to the working voltage V_BAT.

[0013] Preferably, the infrared emitting tube driving module includes: resistors R3 to R4, a triode Q2 and an infrared emitting tube D1; one end of the resistor R3 is connected to PWM_IR, the other end is connected to the base of the triode Q2, the emitter of the triode Q2 is grounded, the collector of the triode Q2 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the infrared emitting tube D1, and the other end of the infrared emitting tube D1 is connected to the working voltage V_BAT.

[0014] Preferably, the button module includes: a switch SW1 and a resistor R5; the pin 2 of the switch SW1 is grounded, the pin 1 of the switch SW1 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the working voltage V_BAT.

[0015] Preferably, the MCU main control module includes: a main control chip U1, PWM_LED, PWM_IR and a capacitor C1; the VCC terminal of the main control chip U1 is respectively connected to the working voltage V_BAT and the capacitor C1, the other end of the capacitor C1 is grounded, the KEY terminal of the main control chip U1 is connected to the pin 1 of the switch SW1, the PWM1 terminal of the main control chip U1 is connected to PWM_LED, the PWM2 terminal of the main control chip U1 is connected to PWM_IR, and the GND terminal of the main control chip U1 is grounded.

[0016] Preferably, the power supply module is two dry batteries.

[0017] Preferably, both the triode Q1 and the triode Q2 are NPN-type triodes.

[0018] Preferably, PWM_LED and PWM_IR are complementary PWM square waves, and their frequencies are 38KHz.

[0019] Compared with the prior art, the present utility model has the following beneficial effects:

[0020] Compared with the circuit that directly drives the LED backlight screen, this circuit avoids the situation where the LED backlight screen and the infrared emitting tube work simultaneously, and adds the dead time of the PWM driving the LED backlight screen, solving the problem of the LED backlight screen flashing when the remote control emits infrared codes. While taking into account the brightness of the LED backlight screen, it also reduces the power consumption of the remote control and extends the battery usage time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a circuit diagram of the existing direct drive method for the LED backlight screen.

[0022] Figure 2 FIG. is a waveform diagram under the direct drive method.

[0023] Figure 3 FIG. is the overall block diagram of the control circuit for the LED backlight screen flashing of the present invention.

[0024] Figure 4 FIG. is the circuit connection diagram of the infrared emitting tube and the LED backlight screen of the present invention.

[0025] Figure 5 FIG. is the circuit connection diagram of the MCU main control module of the present invention.

[0026] Figure 6 FIG. is the circuit connection diagram of the button module of the present invention.

[0027] Figure 7 FIG. is the circuit connection diagram of the LED backlight driving module of the present invention.

[0028] Figure 8 FIG. is the circuit connection diagram of the infrared emitting tube driving module of the present invention.

[0029] Figure 9 FIG. is the circuit connection diagram of the power supply module of the present invention.

[0030] Figure 10 FIG. is the PWM and battery voltage waveform diagram when the remote control of the present invention emits codes. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0032] As Figure 3 shown, the embodiment of the present invention specifically provides a control circuit for solving the problem of the LED backlight screen flashing of the infrared remote control, including:

[0033] MCU main control module;

[0034] A key module, connected to the MCU main control module;

[0035] An LED backlight driving module, connected to the MCU main control module;

[0036] An infrared emitting tube driving module, connected to the MCU main control module;

[0037] A power module, respectively connected to the MCU main control module, the key module, the LED backlight driving module and the infrared emitting tube driving module, for providing working voltage.

[0038] As Figure 4 and 7 shown, the LED backlight driving module includes: resistors R1 to R2, a triode Q1 and an LED backlight screen U2; one end of resistor R1 is connected to PWM_LED, the other end is connected to the base of triode Q1, the emitter of triode Q1 is grounded, the collector of triode Q1 is connected to one end of resistor R2, the other end of resistor R2 is connected to the GND terminal of LED backlight screen U2, and the VCC terminal of LED backlight screen U2 is connected to the working voltage V_BAT.

[0039] As Figure 4 and Figure 8 shown, the infrared emitting tube driving module includes: resistors R3 to R4, a triode Q2 and an infrared emitting tube D1; one end of resistor R3 is connected to PWM_IR, the other end is connected to the base of triode Q2, the emitter of triode Q2 is grounded, the collector of triode Q2 is connected to one end of resistor R4, the other end of resistor R4 is connected to one end of infrared emitting tube D1, and the other end of infrared emitting tube D1 is connected to the working voltage V_BAT.

[0040] As Figure 6 shown, the key module includes: a switch SW1 and a resistor R5; pin 2 of switch SW1 is grounded, pin 1 of switch SW1 is connected to one end of resistor R5, and the other end of resistor R5 is connected to the working voltage V_BAT.

[0041] As Figure 5 shown, the MCU main control module includes: a main control chip U1, PWM_LED, PWM_IR and a capacitor C1; the VCC terminal of main control chip U1 is respectively connected to the working voltage V_BAT and capacitor C1, the other end of capacitor C1 is grounded, the KEY terminal of main control chip U1 is connected to pin 1 of switch SW1, the PWM1 terminal of main control chip U1 is connected to PWM_LED, the PWM2 terminal of main control chip U1 is connected to PWM_IR, and the GND terminal of main control chip U1 is grounded.

[0042] As Figure 9As shown, the power supply module consists of two dry batteries. The MCU main control module configures the timer to output two complementary PWM waves with a frequency of 38KHz, namely PWM_IR and PWM_LED; the rising and falling edge dead times of PWM_LED are configured; PWM_IR provides a 38KHz carrier for driving the infrared emitting tube, and PWM_LED drives the LED backlight screen; when the key switch SW1 is pressed, the MCU main control module judges the key value, modulates PWM_IR, and emits the corresponding key value waveform, such as Figure 10 shown.

[0043] It also includes the following working principle:

[0044] The power supply module provides the working voltage for the MCU main control module, and the MCU main control module operates. The MCU main control module inputs a 38KHz PWM_LED square wave signal to the LED backlight screen driving module, and configures the rising edge dead zone and falling edge dead zone functions of the PWM_LED square wave through the MCU main control module, so that the LED backlight screen driving module operates when the power supply module is stable, avoiding lighting the LED backlight screen when the battery voltage jitters and jumps. The MCU main control module inputs a 38KHz PWM_IR square wave signal to the infrared emitting tube D1 driving module, and configures the PWM_IR square wave to be complementary to the PWM_LED square wave through the MCU main control module, so that the LED backlight screen driving module and the infrared emitting tube driving module work alternately. When the MCU main control module detects that the key switch SW1 is pressed, the MCU main control module starts to modulate the PWM_IR square wave. When the PWM_LED square wave is at a high level, the NPN transistor Q1 conducts, the LED backlight screen is on, and the PWM_IR square wave is complementary to the PWM_LED square wave. At this time, the PWM_IR square wave is at a low level, and the NPN transistor Q2 is cut off, and the infrared emitting tube D1 is turned off; when the PWM_LED square wave is at a low level, the NPN transistor Q1 is cut off, the LED backlight screen is off, and the PWM_IR square wave is complementary to the PWM_LED square wave. At this time, the PWM_IR square wave is at a high level, and the NPN transistor Q2 conducts, and the infrared emitting tube D1 is turned on. This enables the LED backlight screen driving module and the infrared emitting tube driving module to always maintain an alternating working state.

[0045] In summary, the LED backlight screen of the present utility model adopts PWM drive with a frequency of 38KHz, and it is complementary to the PWM for driving the infrared emitting tube, avoiding the situation where both work simultaneously. When driving the LED backlight screen, when the PWM wave is at a high level, the LED backlight screen is on and the infrared emitting tube does not work; when the PWM wave is at a low level, the LED backlight screen is off and the infrared emitting tube works, realizing the alternating operation of the LED backlight screen and the infrared emitting tube. At the same time, dead time is added at the rising edge and falling edge of the PWM wave for driving the LED backlight screen, avoiding the lighting of the LED backlight screen when the battery voltage jitters and jumps, enabling the LED backlight screen to be lit under relatively stable voltage conditions, effectively solving the problem of the LED backlight screen flashing during infrared code transmission of the remote control and reducing the power consumption of the remote control.

[0046] The above description is only a description of the preferred embodiments of the present utility model and does not limit the scope of the present utility model in any way. Any changes and modifications made by those of ordinary skill in the field of the present utility model based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A control circuit to solve the problem of LED backlight screen flickering on infrared remote controller, characterized in that: include: MCU main control module; A button module, connected to the MCU main control module; LED backlight driving module, connected to the MCU main control module; An infrared transmitting tube driving module is connected to the MCU main control module; A power supply module is connected to the MCU main control module, the key module, the LED backlight driving module and the infrared transmitting tube driving module respectively to provide a working voltage; The MCU main control module configures the timer to output two complementary PWM waves with a frequency of 38KHz, namely PWM_IR and PWM_LED; PWM_LED configures the rising and falling edge dead time.

2. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 1, characterized in that: The LED backlight driving module includes: resistors R1~R2, transistor Q1 and LED backlight screen U2; one end of the resistor R1 is connected to PWM_LED, and the other end is connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the GND end of the LED backlight screen U2, and the VCC end of the LED backlight screen U2 is connected to the working voltage V_BAT.

3. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 2, characterized in that: The infrared emitting tube driving module includes: resistors R3~R4, transistor Q2 and infrared emitting tube D1; one end of the resistor R3 is connected to PWM_IR, the other end is connected to the base of the transistor Q2, the emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the infrared emitting tube D1, and the other end of the infrared emitting tube D1 is connected to the working voltage V_BAT.

4. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 3, characterized in that: The key module includes: a switch SW1 and a resistor R5; a pin 2 of the switch SW1 is grounded, a pin 1 of the switch SW1 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to a working voltage V_BAT.

5. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 4, characterized in that: The MCU main control module includes: a main control chip U1, PWM_LED, PWM_IR and a capacitor C1; the VCC end of the main control chip U1 is respectively connected to the working voltage V_BAT and the capacitor C1, the other end of the capacitor C1 is grounded, the KEY end of the main control chip U1 is connected to pin 1 of the switch SW1, the PWM1 end of the main control chip U1 is connected to PWM_LED, the PWM2 end of the main control chip U1 is connected to PWM_IR, and the GND end of the main control chip U1 is grounded.

6. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 1, characterized in that: The power module is 2 dry batteries.

7. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 3, characterized in that: The transistor Q1 and the transistor Q2 are both NPN transistors.

8. A control circuit for solving the problem of LED backlight screen flickering on infrared remote controller as claimed in claim 5, characterized in that: The PWM_LED and PWM_IR are complementary PWM square waves, and the frequency of both is 38KHz.

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