Vehicle gauge level LED driving control system and method

Abstract

The invention relates to the technical field of circuits, and discloses a vehicle-gauge-level LED drive control system and method, and the system comprises a power supply module, a drive module, an LED module, and a control module. The power supply module is connected with the LED module, the driving module and the control module; and the driving module is connected with the control module and the LED module. According to the vehicle-gauge-level LED driving control system, various vehicle-gauge-level chips are adopted, so that the LED driving control system can adapt to various different environments, the vehicle-gauge-level LED driving control system has protection measures such as overvoltage, overcurrent and short circuit to prevent the LED from being damaged, and the reliability of the system is improved.

Description

Technical Field

[0001] This application relates to the field of circuit technologies, and particularly to an automotive-grade LED drive control system and method. Background Art

[0002] Automotive-grade chips are indispensable components in the process of automotive electrification and intelligence. With the rapid growth of data volume in intelligent vehicles, the demand for high-performance chips has also increased significantly. The automotive constant-current LED drive chip is a hot spot in current automotive lighting applications and has occupied a place in the automotive electronic system.

[0003] As an important component of the automotive lighting system, the design requirements of automotive-grade LED chips are getting higher and higher, and they need to have characteristics such as high reliability, high stability, and high safety. In order to ensure the normal operation of the LED circuit in the vehicle and avoid the risks from system failures and random hardware failures, there is an urgent need to study an LED drive control system with high reliability and high safety specifically applied to vehicles. Summary of the Invention

[0004] The purpose of this application is to provide an automotive-grade LED drive control system and method, aiming to solve the technical problem of low reliability of the existing LED drive control system.

[0005] To achieve the above purpose, this application proposes an automotive-grade LED drive control system, which includes: a power supply module, a drive module, an LED module, and a control module;

[0006] The power supply module is connected to the LED module, the drive module, and the control module; the drive module is connected to the control module and the LED module;

[0007] The control module is configured to send a first start signal to the power supply module and a second start signal to the drive module after receiving an external input first voltage signal;

[0008] The power supply module is configured to receive the first start signal and provide a bias voltage for the drive module and the LED module;

[0009] The drive module is configured to receive the second start signal and the bias voltage and deliver a drive current to the LED module;

[0010] The LED module is configured to receive the bias voltage and the drive current to control the lighting and extinguishing of the LED.

[0011] In one embodiment, the automotive-grade LED drive control system further includes: an external power supply module;

[0012] The external power supply module is connected to the power supply module;

[0013] The external power supply module is configured to send the first voltage signal to the power supply module.

[0014] In one embodiment, the vehicle - grade LED driving control system further includes: a buck module;

[0015] The buck module is connected to the external power supply module and the control module;

[0016] The buck module is configured to step down the first voltage signal to a working signal for the control module.

[0017] In one embodiment, the vehicle - grade LED driving control system further includes: a differential driving module;

[0018] Two ends of the differential driving module are respectively connected to two different ports of the control module;

[0019] The differential driving module is configured to receive and process an externally input logic program, and send the processed logic program to the control module;

[0020] The control module is further configured to control the power - on and power - off of the power supply module and the driving module according to the processed logic program.

[0021] In one embodiment, the vehicle - grade LED driving control system further includes: a CAN driving module;

[0022] One end of the CAN driving module is respectively connected to the power supply module, the driving module and the LED module, and the other end of the CAN driving module is connected to the control module;

[0023] The CAN driving module is configured to implement data transmission between the control module and the power supply module, the driving module and the LED module.

[0024] In addition, to achieve the above object, the present application further provides a vehicle - grade LED driving control method, and the vehicle - grade LED driving control method is applied to the vehicle - grade LED driving control system as described above; the method includes:

[0025] Generating a first start signal and a second start signal when receiving an externally input first voltage signal;

[0026] Providing a bias voltage according to the first start signal;

[0027] Adjusting a driving current to the LED according to the second start signal and the bias voltage;

[0028] Receive the bias voltage and the drive current to control the turning on and off of the LED.

[0029] In one embodiment, the step of generating the first start signal and the second start signal when receiving the first voltage signal externally input includes:

[0030] Receive the first voltage signal;

[0031] Step down the first voltage signal to the working signal;

[0032] Generate the first start signal and the second start signal according to the working signal.

[0033] In one embodiment, after the step of receiving the bias voltage and the drive current to control the turning on and off of the LED, it includes:

[0034] Receive and process the externally input logic program to obtain the processed logic program;

[0035] Control the generation of the first start signal and the second start signal according to the processed logic program;

[0036] Repeat the steps of providing the bias voltage according to the first start signal and subsequent steps.

[0037] In one embodiment, the step of receiving and processing the externally input logic program to obtain the processed logic program includes:

[0038] Obtain the externally input logic program;

[0039] Perform syntax checking, logic verification, compilation, and interpretation on the logic program to generate the processed logic program.

[0040] In one embodiment, the step of controlling the generation of the first start signal and the second start signal according to the processed logic program includes:

[0041] Package the processed logic program control as a CAN frame;

[0042] Obtain the voltage status frame and the current status frame in the CAN frame;

[0043] Generate the first start signal according to the voltage status frame and generate the second start signal according to the current status frame.

[0044] This application proposes a vehicle - grade LED drive control system. The vehicle - grade LED drive control system includes: a power supply module, a drive module, an LED module, and a control module; the power supply module is connected to the LED module, the drive module, and the control module; the drive module is connected to the control module and the LED module; the control module is configured to send a first start signal to the power supply module and a second start signal to the drive module after receiving an external input first voltage signal; the power supply module is configured to receive the first start signal and provide a bias voltage for the drive module and the LED module; the drive module is configured to receive the second start signal and the bias voltage and deliver a drive current to the LED module; the LED module is configured to receive the bias voltage and the drive current to control the lighting and extinguishing of the LED. By using a variety of vehicle - grade chips, it is realized that the LED drive control system can adapt to a variety of different environments, and the vehicle - grade LED drive control system has over - voltage, over - current, short - circuit and other protection measures to prevent LED damage and improve the reliability of the system. Description of the Drawings

[0045] Figure 1 It is a schematic diagram of the modules of the first embodiment of the vehicle - grade LED drive control system proposed by this application;

[0046] Figure 2 It is a schematic diagram of the modules of the second embodiment of the vehicle - grade LED drive control system proposed by this application;

[0047] Figure 3 It is a schematic flow diagram of the third embodiment of the vehicle - grade LED drive control method proposed by this application.

[0048] Explanation of the reference numerals in the drawings:

[0049] Label Name Label Name 100 Power supply module 500 External power supply module 200 Driver module 600 Step-down module 300 LED module 700 Differential drive module 400 Control module 800 CAN driver module Detailed Description of the Embodiments

[0050] It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0051] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of this application.

[0052] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the attached drawings). If this specific posture changes, the directional indications will also change accordingly.

[0053] In addition, the descriptions involving "first", "second", etc. in this application are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0054] Refer to Figure 1 , Figure 1 which is a schematic diagram of the modules of the first embodiment of the vehicle - grade LED drive control system proposed in this application. Based on Figure 1 the first embodiment of the vehicle - grade LED drive control system of this application is proposed.

[0055] The vehicle - grade LED drive control system includes: a power supply module 100, a drive module 200, an LED module 300, and a control module 400; the power supply module 100 is connected to the LED module 300, the drive module 200, and the control module 400; the drive module 200 is connected to the control module 400 and the LED module 300.

[0056] It should be understood that the power supply module 100 provides a stable power supply for the entire LED drive control circuit. The power supply module 100 is connected to the LED module 300, the drive module 200, and the control module 400 to ensure the normal operation of these modules.

[0057] It should be noted that the drive module 200 receives instructions from the control module 400, adjusts the current and voltage to drive the LED module 300 to emit light. It usually has functions such as over - current and over - voltage protection to ensure the stable operation of the LED and extend its service life. One end of the drive module 200 is connected to the control module 400 to receive control signals; the other end is connected to the LED module 300 to provide appropriate current and voltage.

[0058] It should be understood that the LED module 300, as a light - emitting element, emits light according to the current and voltage provided by the drive module 200. The LED module 300 receives power from the power supply module 100 and current and voltage control from the drive module 200.

[0059] It should be noted that the control module 400 is responsible for receiving external signals (such as vehicle signal lamp control signals) and adjusting the working state of the driving module 200 according to these signals, so as to control the brightness, color, etc. of the LED module 300. The control module 400 is connected to the power supply module 100 to obtain power, and is also connected to the driving module 200 to send control signals.

[0060] The control module 400 is configured to send a first start signal to the power supply module 100 and a second start signal to the driving module 200 after receiving an externally input first voltage signal.

[0061] It should be noted that the control module 400 is the center of the entire circuit and is responsible for receiving the externally input first voltage signal. This signal may come from other electronic control units (ECUs) of the vehicle or the operations of the driver (such as switch signals). After the control module 400 receives the first voltage signal, it sends a first start signal to the power supply module 100 to activate the power supply module 100; at the same time, the control module 400 also sends a second start signal to the driving module 200 to inform the driving module 200 to be ready to start working.

[0062] The power supply module 100 is configured to receive the first start signal and provide a bias voltage for the driving module 200 and the LED module 300.

[0063] It should be understood that the main responsibility of the power supply module 100 is to provide a stable power supply for the driving module 200 and the LED module 300, including the bias voltage. The bias voltage is the reference voltage required for the normal operation of the LED module 300. After receiving the first start signal from the control module 400, the power supply module 100 starts to work and provides the required bias voltage for the driving module 200 and the LED module 300. This bias voltage enables the driving module 200 and the LED module 300 to be in a standby state and ready to receive further instructions.

[0064] The driving module 200 is configured to receive the second start signal and the bias voltage and deliver a driving current to the LED module 300.

[0065] It should be noted that the driving module 200 is responsible for adjusting the current according to the instructions of the control module 400 to drive the LED module 300 to emit light. It is also responsible for protecting the LED module 300 from damage caused by overcurrent and overvoltage. After receiving the second start signal from the control module 400 and the bias voltage provided by the power supply module 100, the driving module 200 starts to deliver a driving current to the LED module 300. The magnitude and characteristics of the driving current depend on the specific requirements of the LED module 300.

[0066] The LED module 300 is configured to receive the bias voltage and the drive current to control the lighting and extinguishing of the LED.

[0067] It should be understood that the LED module 300 is the output part of the circuit, responsible for emitting light or extinguishing according to the received current and voltage. After receiving the bias voltage provided by the power supply module 100 and the drive current delivered by the drive module 200, the LED module 300 controls the lighting and extinguishing of the LED according to these electrical signals. If the drive current exists, the LED will emit light; if the drive current is cut off, the LED will extinguish.

[0068] This embodiment provides a vehicle - grade LED drive control system, which includes: a power supply module 100, a drive module 200, an LED module 300, and a control module 400; the power supply module 100 is connected to the LED module 300, the drive module 200, and the control module 400; the drive module 200 is connected to the control module 400 and the LED module 300; the control module 400 is configured to send a first start signal to the power supply module 100 and a second start signal to the drive module 200 after receiving an external input first voltage signal; the power supply module 100 is configured to receive the first start signal and provide a bias voltage for the drive module 200 and the LED module 300; the drive module 200 is configured to receive the second start signal and the bias voltage and deliver a drive current to the LED module 300; the LED module 300 is configured to receive the bias voltage and the drive current to control the lighting and extinguishing of the LED. By using a variety of vehicle - grade chips, it is realized that the LED drive control system can adapt to a variety of different environments, and the vehicle - grade LED drive control system has over - voltage, over - current, short - circuit and other protection measures to prevent the LED from being damaged and improve the reliability of the system.

[0069] Refer to Figure 2 , Figure 2 is a schematic diagram of the modules of the second embodiment of the vehicle - grade LED drive control system proposed in this application. Based on the first embodiment of the above - mentioned vehicle - grade LED drive control system, the second embodiment of the vehicle - grade LED drive control system of this application is proposed.

[0070] The vehicle - grade LED drive control system further includes: an external power supply module 500; the external power supply module 500 is connected to the power supply module 100; the external power supply module 500 is configured to send the first voltage signal to the power supply module 100.

[0071] It should be noted that the external power supply module 500 is the external power input part of the entire LED drive control circuit. It is responsible for converting the vehicle's main power supply (such as a 12V or 24V DC power supply) into the first voltage signal required by the circuit. This signal is usually a relatively low voltage, suitable for use in the electronic control circuit. The external power supply module 500 is connected to the power supply module to provide power input to it. The external power supply module 500 sends the first voltage signal to the power supply module. This signal is the basis for the power supply module to start and operate. After receiving the first voltage signal from the external power supply module 500, the power supply module converts it into the bias voltage required by other modules in the circuit (such as the drive module 200 and the LED module 300).

[0072] The vehicle-grade LED drive control system further includes: a buck module 600; the buck module 600 is connected to the external power supply module 500 and the control module 400; the buck module 600 is used to step down the first voltage signal to a working signal and send it to the control module 400.

[0073] It should be understood that the main function of the buck module 600 is to reduce the first voltage signal provided by the external power supply module 500 (usually a relatively high voltage, such as 12V or 24V of the vehicle battery) to a voltage level suitable for the operation of the control module 400. This working signal is usually a relatively low voltage, such as 5V or 3.3V, which is the standard working voltage of most electronic control circuits. The buck module 600 is connected to the external power supply module 500 and the control module 400. It receives the first voltage signal from the external power supply module 500, steps it down, and then outputs it to the control module 400. The buck module 600 receives the first voltage signal from the external power supply module 500. The buck module 600 steps down the first voltage signal to a working signal and sends it to the control module 400.

[0074] The vehicle-grade LED drive control system further includes: a differential drive module 700; both ends of the differential drive module 700 are respectively connected to two different ports of the control module 400;

[0075] The differential drive module 700 is used to receive and process the externally input logic program, and send the processed logic program to the control module 400; the control module 400 is further used to control the turning on and off of the power supply module 100 and the drive module 200 according to the processed logic program.

[0076] It should be noted that the differential drive module 700 is used to receive externally input logical programs, which may contain control information such as the on / off pattern, brightness adjustment, and blinking frequency of the LEDs. The differential drive module 700 processes these logical programs to ensure that the signals have higher anti-interference capabilities during transmission, especially in the automotive environment where electromagnetic interference (EMI) is relatively severe. The two ends of the differential drive module 700 are respectively connected to two different ports of the control module 400, which are usually differential pair interfaces capable of receiving differential signals. The differential drive module 700 receives the externally input logical programs and processes them. The processed logical programs are sent to the control module 400 in the form of differential signals.

[0077] It should be understood that in addition to sending a startup signal to the power supply module 100 and the drive module 200, the control module 400 now also controls the turning on and off of the power supply module 100 and the drive module 200 according to the logical programs processed by the differential drive module 700. This means that the control module 400 can adjust the working state of the LED module 300 according to the received logical programs, such as changing the brightness, achieving a dynamic lighting effect, or adjusting the behavior of the LEDs according to the vehicle state (such as turning, braking, etc.).

[0078] The in-vehicle LED drive control system further includes: a CAN drive module 800; one end of the CAN drive module 800 is respectively connected to the power supply module 100, the power supply module 100, and the LED module 300, and the other end of the CAN drive module 800 is connected to the control module 400;

[0079] The CAN drive module 800 is used to implement data transmission between the control module 400 and the power supply module 100, the power supply module 100, and the LED module 300.

[0080] It should be noted that the CAN drive module 800 is part of the Controller Area Network, which is used to implement data communication between the control module 400, the power supply module 100, the power supply module 100, and the LED module 300. The CAN bus is a high-performance communication protocol widely used in automotive electronic systems and can effectively support communication between multiple network nodes. One end of the CAN drive module 800 is respectively connected to the power supply module 100, the power supply module 100, and the LED module 300, and the other end is connected to the control module 400. In this way, it forms a bridge for data transmission, enabling the control module 400 to monitor and command other modules. The CAN drive module 800 allows the control module 400 to send control commands and data to the power supply module 100, the power supply module 100, and the LED module 300. At the same time, it also allows these modules to feedback status information, fault codes, or other data to the control module 400 for real-time monitoring and management.

[0081] In this embodiment, the power supply module 100 is responsible for providing the required voltage for the power supply module 100 and the LED module 300. The power supply module 100 is responsible for converting the external input voltage into the voltage required by the control module 400. The control module 400 is responsible for converting the external input logic program and controlling the on and off of the power supply module 100, the power supply module 100. Both the CAN drive module 800 and the differential drive module 700 use automotive-grade interface chips for between the CAN protocol controller and the physical bus. By using a variety of automotive-grade chips, it is realized that the LED drive control system can adapt to a variety of different environments, and the automotive-grade LED drive control system has overvoltage, overcurrent, short-circuit and other protection measures to prevent LED damage and improve the reliability of the system. At the same time, it has a variety of dimming modes and can be configured and adjusted according to the selection.

[0082] Refer to Figure 3 , Figure 3 is a schematic flowchart of the third embodiment of the automotive-grade LED drive control method proposed in this application. Based on the first and second embodiments of the above automotive-grade LED drive control system, the third embodiment of the automotive-grade LED drive control method of this application is proposed.

[0083] The automotive-grade LED drive control method includes:

[0084] Step S10: Generate a first start signal and a second start signal when receiving an externally input first voltage signal;

[0085] Step S20: Provide a bias voltage according to the first start signal;

[0086] Step S30: Adjust the drive current to the LED according to the second start signal and the bias voltage;

[0087] Step S40: Receive the bias voltage and the drive current to control the lighting and extinguishing of the LED.

[0088] It should be understood that the system first detects an externally input voltage signal, which serves as the initial signal to trigger the LED drive. After receiving the external voltage signal, a first start signal is generated inside the system, which is used to activate the provision of the bias voltage. At the same time, a second start signal is also generated by the system, which is used to subsequently adjust the drive current of the LED. After the first start signal is activated, the system provides a stable bias voltage, which is necessary for the normal operation of the LED. The drive current is adjusted to the LED according to the second start signal and the bias voltage: under the action of the second start signal, the system adjusts the magnitude of the drive current according to the value of the bias voltage to ensure that the LED can work with an appropriate current, thereby ensuring the brightness and stability of the LED. Finally, the system precisely controls the lighting and extinguishing states of the LED by controlling the on / off of the bias voltage and the drive current. When the bias voltage and the drive current are turned on, the LED lights up; when the bias voltage and the drive current are turned off, the LED goes out.

[0089] Further, step S10 specifically includes: receiving the first voltage signal; stepping down the first voltage signal to the working signal; generating the first start signal and the second start signal according to the working signal.

[0090] Further, after step S40, it includes: receiving and processing an externally input logic program to obtain the processed logic program; controlling the generation of the first start signal and the second start signal according to the processed logic program; repeating the steps of providing the bias voltage according to the first start signal and subsequent steps.

[0091] It should be understood that the step of receiving and processing an externally input logic program to obtain the processed logic program includes: obtaining the externally input logic program; performing syntax checking, logic verification, compilation, and interpretation on the logic program to generate the processed logic program.

[0092] It should be noted that the step of controlling the generation of the first start signal and the second start signal according to the processed logic program includes: encapsulating the processed logic program control into a CAN frame; obtaining the voltage status frame and the current status frame in the CAN frame; generating the first start signal according to the voltage status frame and generating the second start signal according to the current status frame.

[0093] In this embodiment, the vehicle-grade LED drive control method includes generating a first start signal and a second start signal after receiving an externally input first voltage signal; providing a bias voltage according to the first start signal; adjusting a drive current to an LED according to the second start signal and the bias voltage; and receiving the bias voltage and the drive current to control the lighting and extinguishing of the LED. By using a variety of vehicle-grade chips, it is realized that the LED drive control system can adapt to a variety of different environments. By precisely controlling the current and voltage through a logic program, the reliability and service life of the LED can be ensured.

[0094] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover a non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without more limitations, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or system including that element.

[0095] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. An automotive-grade LED drive control system, characterized in that: The automotive-grade LED drive control system includes: a power supply module, a drive module, an LED module and a control module; The power supply module is connected to the LED module, the driving module and the control module; the driving module is connected to the control module and the LED module; The control module is used to send a first start signal to the power supply module and send a second start signal to the drive module after receiving a first voltage signal input from the outside; The power supply module is used to receive the first start signal and provide a bias voltage for the driving module and the LED module; The driving module is used to receive the second start signal and the bias voltage and transmit a driving current to the LED module; The LED module is used to receive the bias voltage and the driving current to control the LED to turn on and off.

2. The automotive-grade LED drive control system according to claim 1, characterized in that: The automotive-grade LED drive control system further includes: an external power supply module; The external power supply module is connected to the power supply module; The external power supply module is used to send the first voltage signal to the power supply module.

3. The automotive-grade LED drive control system according to claim 2, characterized in that: The automotive-grade LED drive control system further includes: a buck module; The step-down module is connected to the external power supply module and the control module; The voltage reduction module is used to reduce the voltage of the first voltage signal into a working signal and transmit it to the control module.

4. The automotive-grade LED drive control system according to claim 1, characterized in that: The automotive-grade LED drive control system further includes: a differential drive module; Two ends of the differential driving module are respectively connected to two different ports of the control module; The differential driving module is used to receive and process the logic program input from the outside, and send the processed logic program to the control module; The control module is also used to control the opening and closing of the power supply module and the driving module according to the processed logic program.

5. The automotive-grade LED drive control system according to claim 1, characterized in that: The automotive-grade LED drive control system further includes: a CAN drive module; One end of the CAN driving module is connected to the power supply module, the driving module and the LED module respectively, and the other end of the CAN driving module is connected to the control module; The CAN driving module is used to realize data transmission between the control module and the power supply module, and between the driving module and the LED module.

6. A vehicle-grade LED drive control method, characterized in that: The automotive-grade LED drive control method is applied to the automotive-grade LED drive control system according to any one of claims 1 to 5; the method comprises: Generate a first start signal and a second start signal after receiving a first voltage signal input from the outside; providing a bias voltage according to the first start signal; adjusting a driving current to the LED according to the second start signal and the bias voltage; The bias voltage and the driving current are received to control the LED to turn on or off.

7. The automotive-grade LED driving control method according to claim 6, characterized in that: The step of generating a first start signal and a second start signal after receiving a first voltage signal input from an external source comprises: receiving the first voltage signal; Stepping down the first voltage signal into the working signal; The first start signal and the second start signal are generated according to the working signal.

8. The automotive-grade LED driving control method according to claim 6, characterized in that: After the step of receiving the bias voltage and the driving current to control the LED on and off, the method further comprises: Receive and process the logic program input from the outside, and obtain the processed logic program; controlling the generation of the first start signal and the second start signal according to the processed logic program; Repeat the steps of providing a bias voltage according to the first start signal and subsequent steps.

9. The automotive-grade LED driving control method according to claim 8, characterized in that: The step of receiving and processing the externally inputted logic program and obtaining the processed logic program comprises: Obtaining the logic program of external input; The logic program is subjected to syntax checking, logic verification, compilation and interpretation to generate the processed logic program.

10. The automotive-grade LED driving control method according to claim 8, characterized in that: The step of controlling the generation of the first start signal and the second start signal according to the processed logic program comprises: Encapsulating the processed logic program control into a CAN frame; Acquire a voltage state frame and a current state frame in the CAN frame; The first start signal is generated according to the voltage state frame, and the second start signal is generated according to the current state frame.

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