Interface multiplexing circuit, air conditioner

Abstract

The utility model discloses an interface multiplexing circuit, air conditioning. Among them interface multiplexing circuit, including: main control board controller, with signal interface of main control board controller connection, set up between main control board controller and signal interface at least one wave form generating circuit, main control board controller controls wave form generating circuit to produce different wave form signal, and exports through signal interface to control a plurality of external devices. The utility model discloses through the wave form generating circuit of addition, makes controller can produce a plurality of different wave form signals to make an interface can control a plurality of external devices, has improved the utilization of physical interface.

Description

Technical Field

[0001] This utility model relates to the technical field of interface multiplexing, and in particular to an interface multiplexing circuit. Background Technology

[0002] Physical interfaces (such as pin headers, connectors, and ports) on circuit boards (such as the main control board of electronic devices) are the key channels for the system to interact with the outside world. Each interface carries a specific, preset function. For example, data transmission interfaces are used to connect displays, printers, storage devices, etc., while control signal interfaces are used to connect sensors, switches, actuators, etc.

[0003] During the product development, testing, and production stages, there are often specific requirements applicable to certain stages. These requirements are not the final functions that the product can provide to users. The most common example is the production testing requirement. Taking the main control board of a central air conditioning indoor unit as an example, a dedicated test interface needs to be prepared. This test interface allows testing equipment on the production line (such as test fixtures and jigs) to quickly connect to the main control board. Through this test interface, the testing equipment can send specific test command sequences to the main control board, and the indoor unit main control board returns key hardware status information through this test interface. For example, the configuration number of the currently installed jumper cap (used to identify different models or function options), the initialization status or self-test results of key chips (such as MCU, EEPROM, and communication modules), whether the communication links between the various internal modules of the central air conditioning (such as temperature sensors, fan drives, display modules, and communication buses) are unobstructed (e.g., sending a PING command and receiving an ACK response), and whether the approximate values ​​of key voltage points are within the expected range, etc.

[0004] After production testing was completed, the test interface was no longer used, resulting in low utilization of the circuit interface.

[0005] Therefore, how to provide an interface multiplexing circuit to improve the utilization rate of circuit interfaces is a technical problem to be solved. Utility Model Content

[0006] In order to solve the technical problem of low utilization rate of certain interfaces in existing circuits, this utility model proposes an interface multiplexing circuit and an air conditioner.

[0007] The interface multiplexing circuit of this utility model includes:

[0008] The main control board controller, the signal interface connected to the main control board controller, and at least one waveform generation circuit disposed between the main control board controller and the signal interface;

[0009] The main control board controller controls the waveform generation circuit to generate different waveform signals, and outputs them through the signal interface to control multiple external devices.

[0010] Furthermore, the waveform generation circuit is a PWM waveform generation circuit.

[0011] Furthermore, the waveform generation circuit includes at least two waveform generation circuits among the following: sine wave generation circuit, square wave generation circuit, PWM wave generation circuit, and sawtooth wave generation circuit.

[0012] Furthermore, the PWM wave generation circuit includes a clock source for generating a clock signal and a timer for timing based on the clock signal, and the main control board controller outputs a PWM waveform signal based on the timer.

[0013] Furthermore, the sawtooth wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, a main control board controller for outputting a PWM waveform signal based on the timer, an integrator for performing integration operations on the PWM waveform signal, and a filter for filtering the output of the integrator.

[0014] Furthermore, the sine wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, a digital-to-analog converter for receiving signals from the main control board controller based on the timer output and the sine lookup table operation output, and a filter for filtering the output of the digital-to-analog converter.

[0015] Furthermore, the external device includes at least one of a temperature controller and an online testing device.

[0016] The air conditioner proposed in this utility model includes the interface multiplexing circuit of the above-mentioned technical solution.

[0017] Furthermore, the interface multiplexing circuit is located on the main control board of the indoor unit of the air conditioner.

[0018] This invention controls the output of analog signals with different characteristics and simultaneously controls different timing sequences to represent different functions, thereby enabling the connection to different external devices. Taking a central air conditioner as an example, it can realize the reuse of interfaces for online testing and simple low-speed communication, thereby improving the utilization rate of hardware interfaces. Attached Figure Description

[0019] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0020] Figure 1 This is a circuit block diagram illustrating the main concept of this utility model.

[0021] Figure 2 This is a circuit block diagram of the first embodiment of this utility model.

[0022] Figure 3 This is a circuit block diagram of the second embodiment of the present invention.

[0023] Figure 4 This is a circuit block diagram of a PWM wave generation circuit according to an embodiment of the present invention.

[0024] Figure 5 This is a circuit block diagram of a sawtooth wave generating circuit according to an embodiment of the present invention.

[0025] Figure 6 This is a circuit block diagram of a sine wave generating circuit according to an embodiment of the present invention.

[0026] Figure 7 This is a control flowchart of an application example of this utility model. Detailed Implementation

[0027] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0028] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0029] like Figure 1 As shown, the interface multiplexing circuit of this utility model includes a main control board controller, a signal interface, and a waveform generation circuit.

[0030] The main control board controller is used to output control signals or receive signals input from the outside.

[0031] The waveform generation circuit is located between the main control board controller and the signal interface. It generates different waveform signals based on the control signals output by the main control board controller.

[0032] The signal interface connects to external devices to transmit different waveform signals to the external devices, or to send signals returned by the external devices to the main control board controller connected to the signal interface according to a predetermined protocol.

[0033] The main control board controller of this utility model generates different waveform signals through a waveform generation circuit, so that a single signal interface can output different control signals to connect to different external devices. This allows temporary interfaces that are not part of the final product requirements to be reused, avoiding idleness.

[0034] like Figure 2 As shown, in one embodiment, the waveform generation circuit of this utility model is a PWM waveform generation circuit.

[0035] Taking the main control board circuit of a central air conditioner as an example, there is a signal interface on the main control board circuit of the central air conditioner that needs to be used for testing during the testing phase. In order to reuse this signal interface in subsequent processes, this embodiment uses it to control the thermostat. That is, the external devices include the online testing device and the thermostat.

[0036] Specifically, initially, the main control board circuit is connected to the online testing device. Before powering on, the main control board circuit performs online testing for a period of time (e.g., within one minute). During this time, a PWM wave of frequency A is used to send signals. PWM waves with different duty cycles and different peak-to-peak values ​​at this frequency represent different hardware states, which are then read by the machines on the production line (online testing device). If a wave with a specific duty cycle and peak value can be read, it proves that the production assembly is correct; otherwise, it indicates an error that requires manual intervention.

[0037] After successful testing, during the operation of the central air conditioning system, this signal interface can be connected to the thermostat. At this point, a PWM wave of frequency B is used to send communication signals. Different duty cycles of the PWM wave at this frequency represent different information. The thermostat receives and analyzes the PWM wave signals from the main control board circuit. When the thermostat recognizes a signal frequency of frequency A (i.e., an online test signal), it does not respond. When it recognizes a signal frequency of frequency B (i.e., correctly recognizes the communication signal from the main control board circuit), the thermostat analyzes its duty cycle and reads the corresponding information. Similarly, after the duty cycle of frequency B is exhausted, other frequencies such as C and D can be used to identify other information.

[0038] In one embodiment, the waveform generation circuit includes at least two of the following: a sine wave generation circuit, a square wave generation circuit, a PWM wave generation circuit, and a sawtooth wave generation circuit. By using multiple waveform generation circuits, more waveform signals can be generated, thereby enabling a single signal interface to output more control signals.

[0039] Taking the main control board circuit of a central air conditioning system as an example, there is a signal interface on the main control board circuit that needs to be used for testing during the testing phase. In order to reuse this signal interface in subsequent processes, this embodiment uses it to control the thermostat. That is, the external devices include the online testing device and the thermostat.

[0040] Initially, the main control board circuit is connected to the online testing device. Before powering on, the main control board circuit performs online testing for a period of time (e.g., within one minute). During this time, a waveform generation circuit can be used to send signals. For example, when a PWM waveform generation circuit sends signals, PWM waves with different frequencies, and / or different duty cycles, and / or different peak-to-peak values ​​represent different hardware states. These are read by the machines on the production line (online testing device) to verify whether the corresponding hardware assembly is correct and / or whether communication is normal.

[0041] After the test is completed without any problems, the signal interface can be connected to the thermostat during the operation of the central air conditioning system. At this time, another waveform generation circuit can be used to send control signals. For example, a square wave generation circuit can be used to send the corresponding waveform signal. When the thermostat recognizes the correct signal, it analyzes the duty cycle of the signal and reads the corresponding information.

[0042] like Figure 3 As shown, in one embodiment, the waveform generation circuit includes a sine wave generation circuit, a sawtooth wave generation circuit, and a PWM wave generation circuit. Through these three different waveform generation circuits, the signal interface can control different external devices.

[0043] It should be noted that different waveform signals can be used for different controls of the same external device, or for different controls of different external devices. For example, different PWM waves can be used for online testing. When a communication connection needs to be established with a temperature controller, a sawtooth wave can be sent to establish the connection. When the temperature controller needs to perform a self-test during the control process, a sine wave can be used for the self-test.

[0044] like Figure 4 As shown, in one embodiment, the PWM wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, and a main control board controller outputting a PWM waveform signal based on the timer.

[0045] In this embodiment, the main control board controller can output the corresponding PWM waveform with the help of a clock source and a timer, thereby controlling the corresponding external devices. The circuit structure is simple and easy to implement.

[0046] like Figure 5 As shown, the sawtooth wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, a main control board controller outputting a PWM waveform signal based on the timer, an integrator for performing integral operations on the PWM waveform signal, a filter for filtering the output of the integrator, and finally outputting a sawtooth wave signal.

[0047] This sawtooth wave generation circuit, based on the PWM wave generation circuit, processes the PWM waveform through an integrator and a filter to generate a sawtooth wave signal. The circuit structure is simple and increases the variety of waveforms.

[0048] like Figure 6 As shown, in one embodiment, the sine wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, a digital-to-analog converter for receiving signals from the main control board controller based on the timer output and the sine lookup table operation output, a filter for filtering the output of the digital-to-analog converter, and finally outputting a sine wave signal.

[0049] This embodiment mainly uses the main control board controller to perform a sine lookup table operation based on a clock source and timer, and then uses a digital-to-analog converter to perform digital-to-analog conversion to obtain a sine wave signal. The circuit is simple and can generate different waveform signals, providing different signal foundations for the main control board controller to control different external devices.

[0050] The external devices of this invention include, but are not limited to, temperature controllers and online testing devices. Those skilled in the art can control different external devices as needed. This not only provides flexible control but also improves the utilization rate of the interfaces.

[0051] This utility model also protects an air conditioner that includes the interface multiplexing circuit of the above-described technical solution.

[0052] In one embodiment, the interface reuses the circuit on the main control board of the indoor unit of the air conditioner.

[0053] The online test interface on the main control board will be used as a specific example of a signal interface for illustration.

[0054] This online test interface connects to an output pin of the main control board's controller, and outputs a suitable PWM wave, sawtooth wave, or sine wave through a waveform generation circuit. The specific output waveform is controlled by the main control board controller, which controls the current signal output of the output pin according to the protocol and timing control logic, and then converts it into the target control signal through the waveform generation circuit.

[0055] The sine wave generation circuit, square wave generation circuit, and PWM wave generation circuit are three independent sub-modules. Each waveform generation circuit is responsible for generating a certain type of analog signal and is controlled by the main control board controller. After receiving the signal output corresponding to the output pin, it generates an analog signal that meets the requirements.

[0056] The thermostat uses a signal detection and analysis module to detect and analyze the control signal. If it is a correct control signal, it performs signal recognition processing. Signal recognition processing includes, but is not limited to, the identification of analog parameters such as waveform, frequency, and peak value. The thermostat's controller receives the characteristics of the control signal fed back by the signal detection and analysis module, including its waveform, peak value, and other parameters. If it is identified as a PWM wave, it will also feed back its duty cycle information.

[0057] With the above structure, the main control board and thermostat system of the central air conditioning system of this utility model can transmit simple information by using analog signals of different types and characteristics without the need for additional development of communication interfaces, thereby improving efficiency and reducing development costs.

[0058] The communication process is described in detail below. Figure 7 As shown, after the main control board is powered on, online testing is performed within a certain period of time (e.g., within 1 minute). Assuming that the corresponding control signal is sent by a PWM wave of a certain frequency, different duty cycles and different peak values ​​of the PWM wave at this frequency can be used to represent different hardware states.

[0059] For example, if a 500Hz PWM wave is used to send online detection signals, and different duty cycles and peak values ​​are needed to represent different jumper cap numbers, then a 5% duty cycle plus a 5V peak value can represent jumper cap number 1, a 5% duty cycle plus a 10V peak value can represent jumper cap number 2, a 10% duty cycle plus a 5V peak-to-peak value can represent jumper cap number 3, and so on. When the online testing device detects a 5% duty cycle and a 5V peak value, it indicates that jumper cap number 1 is installed on the main control board; detecting a 5% duty cycle plus a 5V peak-to-peak value indicates that jumper cap number 2 is installed. If this does not match the expectation, it indicates that the jumper cap was installed incorrectly during the production process. In practice, it has been found that the online detection and verification time for each main control board does not exceed one minute. Therefore, setting a one-minute interval for sending online test information is reasonable in this specific scenario. In other application scenarios, those skilled in the art can change the interval of the sent control signals according to the circumstances.

[0060] After power-on time exceeds one minute, the main control board enters communication mode. At this point, the main control board controller stops sending online test signals and switches to sending signals specified in the communication protocol. Assuming a PWM wave of frequency B is used to send communication signals, different duty cycles of the PWM wave at this frequency represent different information. Before sending the PWM wave representing communication information, a sawtooth wave of a certain duration is sent to indicate that communication is in progress; for example, a sawtooth wave of 500ms or 1s can be continuously sent. The temperature controller receives and analyzes different analog signals from the main control board. When it recognizes a PWM wave of frequency A and does not detect a sawtooth wave, it considers this not a correct control signal and does not respond. When a sawtooth wave of a certain duration is detected, the temperature controller enters the communication signal receiving state, subsequently receiving the PWM wave sent from the main control board, analyzing its duty cycle, and reading the corresponding information. Similarly, after the duty cycle of frequency B is exhausted, different peak-to-peak values ​​can be used, or other frequencies such as frequency C and frequency D can be used to identify other information. To ensure the signal has a certain level of anti-interference capability, the duty cycle intervals representing different information need to be spaced out, within the error range that the hardware can recognize. Generally, an interval of 5% or 10% is considered appropriate. A certain time interval is also allowed for the conversion of different types of analog signals to ensure that signal processing can proceed normally.

[0061] For example, if a 1kHz PWM wave with a peak-to-peak value of 10V is used to identify communication, and a 5% duty cycle indicates fault 1, a 10% duty cycle indicates fault 2, and so on, and a 500ms sawtooth wave with a peak-to-peak value of 8V is agreed upon as the header of the communication signal, the temperature controller will first detect the 500ms sawtooth wave. If the received peak-to-peak value is basically consistent with expectations, it will begin detecting the communication signal. When the temperature controller recognizes a 1kHz PWM waveform signal with a peak-to-peak value of 10V and a duty cycle of 5%, it indicates that fault 1 has occurred on the main control board. At this time, the temperature controller can take relevant actions according to the operating logic, such as protective shutdown or shutting down the load output. When the temperature controller recognizes a 1kHz PWM waveform signal with a duty cycle of 10% but a peak-to-peak value of 5V, it means that the signal does not match the agreement, and the temperature controller will not respond to this signal. In actual temperature controller software signal processing, in order to account for possible errors, there is generally a certain error tolerance for the recognition signal range, such as allowing an error of ±1% or ±2%.

[0062] When interfaces are reused in the air conditioning field, the aforementioned signal interfaces, in addition to transmitting fault information, can also perform self-testing using feedback signals when the user turns off the air conditioner or it has not been used for an extended period. Self-testing refers to the thermostat sending a series of agreed-upon operational commands to the main control board. The main control board checks whether the received commands meet expectations, thereby detecting any problems with the thermostat or the main control board. For example, the main control board and the display board may agree to use a sine wave of a specific frequency to represent the self-test signal, such as a 2kHz sine wave. When the thermostat recognizes a 2kHz sine wave signal, it indicates that the main control board is performing a self-test, requiring the thermostat to execute a series of agreed-upon operations. After the thermostat completes the operations, the main control board receives the corresponding command and sends a self-test success signal. If no corresponding command is received within a certain time, the self-test is considered to have failed, and the main control board sends a self-test failure signal. Upon receiving this signal, the thermostat outputs a corresponding warning to the user, prompting them to check for any abnormalities in the air conditioning system.

[0063] This invention relates to a temperature controller that can transmit simple information using existing online interfaces without the need for additional communication interface development. Information is transmitted between the main control board and the temperature controller through simple analog signal waveforms. This online test interface reuse method can be applied to cost-reduction projects and also to the retrofitting of older main control boards.

[0064] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An interface multiplexing circuit, characterized in that, include: The main control board controller, the signal interface connected to the main control board controller, and at least one waveform generation circuit disposed between the main control board controller and the signal interface; The main control board controller controls the waveform generation circuit to generate different waveform signals and outputs them through the signal interface to control multiple external devices. The waveform generation circuit is a PWM waveform generation circuit, which includes a clock source for generating a clock signal and a timer for timing based on the clock signal. The main control board controller outputs the PWM waveform signal based on the timer.

2. The interface multiplexing circuit as described in claim 1, characterized in that, The external device includes at least one of a temperature controller and an online testing device.

3. An interface multiplexing circuit, characterized in that, include: The main control board controller, the signal interface connected to the main control board controller, and at least one waveform generation circuit disposed between the main control board controller and the signal interface; The main control board controller controls the waveform generation circuit to generate different waveform signals and outputs them through the signal interface to control multiple external devices. The waveform generation circuit includes at least two of the following: a sine wave generation circuit, a square wave generation circuit, a PWM waveform generation circuit, and a sawtooth wave generation circuit. The sawtooth wave generation circuit includes a clock source for generating a clock signal, a timer for timing based on the clock signal, a main control board controller for outputting a PWM waveform signal based on the timer, an integrator for performing integral operations on the PWM waveform signal, and a filter for filtering the output of the integrator.

4. The interface multiplexing circuit as described in claim 2, characterized in that, The external device includes at least one of a temperature controller and an online testing device.

5. An interface multiplexing circuit, characterized in that, include: The main control board controller, the signal interface connected to the main control board controller, and at least one waveform generation circuit disposed between the main control board controller and the signal interface; The main control board controller controls the waveform generation circuit to generate different waveform signals and outputs them through the signal interface to control multiple external devices. The waveform generation circuit includes at least two of the following: a sine wave generation circuit, a square wave generation circuit, a PWM waveform generation circuit, and a sawtooth wave generation circuit. The sine wave generation circuit includes a clock source for generating clock signals, a timer for timing based on the clock signals, a digital-to-analog converter for receiving signals from the main control board controller based on the timer output and the sine lookup table operation output, and a filter for filtering the output of the digital-to-analog converter.

6. The interface multiplexing circuit as described in claim 5, characterized in that, The external device includes at least one of a temperature controller and an online testing device.

7. An air conditioner, characterized in that, Includes the interface multiplexing circuit as described in any one of claims 1-6.

8. The air conditioner as described in claim 7, characterized in that, The interface multiplexing circuit is located on the main control board of the indoor unit of the air conditioner.

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