PWM signal generator and function signal generator including same
By controlling the switching devices and power amplification devices of the PWM signal generator, combined with a CAN box and a timer, the problem of high power loss in the PWM signal generator was solved, achieving the effects of reducing power loss and improving signal accuracy.
Patent Information
- Application Number
- CN202423080115.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2034-12-12
AI Technical Summary
Existing PWM signal generators suffer from significant power loss when outputting PWM signals with corresponding duty cycles.
By controlling the circuit's on/off state using switching devices and combining them with power amplification devices, power loss is reduced. The duty cycle is controlled using a CAN box and a timer, and signal accuracy is improved by employing cement resistors and operational amplifiers.
It achieves reduced power loss and improved signal accuracy when outputting PWM signals, and has a simple overall structure, small size, and is easy to place and move.
Smart Images
Figure CN223872264U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of signal generator technology, and more specifically, to a PWM signal generator and a function signal generator including the same. Background Technology
[0002] PWM (Pulse Width Modulation) is a method of digitally encoding analog signal levels using a high-resolution counter. Due to its advantages such as low cost, space saving, and strong anti-interference capability, it is widely used in control applications.
[0003] In control scenarios, the duty cycle of a PWM signal can be controlled by switching between high and low levels and adjusting the duration of the high level, thereby achieving the corresponding control mechanism. For example, when controlling the speed of a motor or water pump, the speed can be adjusted by changing the duty cycle of the PWM signal. As another example, when controlling the charging process of a battery, the duty cycle of the PWM signal can be adjusted to control the generated CP signal (Charge Pulses). Furthermore, the duty cycle of the PWM signal can also be adjusted to control the volume or frequency of crash signals (collision signals) and alarm signals (fault alarm signals). Utility Model Content
[0004] The purpose of this application is to provide a PWM signal generator and a function signal generator including the same, so as to reduce power loss when outputting a PWM signal.
[0005] In a first aspect, embodiments of this application provide a PWM signal generator, comprising: a switching device, wherein a first terminal of the switching device is connected to signal ground and a second terminal is connected to a power supply via a current limiting device; and a power amplification device, wherein the input terminal of the power amplification device is connected to the second terminal and the output terminal of the power amplification device is used to output a PWM signal. This allows the PWM signal generator to reduce power loss when outputting a PWM signal with a corresponding duty cycle.
[0006] Optionally, the power amplification device includes a first resistor, a second resistor, and an operational amplifier; wherein the positive input terminal of the operational amplifier is connected to the second terminal, the negative input terminal of the power amplification device is connected to the power supply through the first resistor and grounded through the second resistor, and the output terminal of the operational amplifier is used to output a PWM signal. This improves the load-carrying capacity of the external output and reduces power loss during circuit operation.
[0007] Optionally, the first resistor and the second resistor have the same resistance value. This helps to improve the accuracy of the output PWM signal.
[0008] Optionally, the values of the first resistor and the second resistor can range from 10K ohms to 100K ohms. This improves the accuracy of the PWM signal and makes it more suitable for applications controlled via a CAN box.
[0009] Optionally, the PWM signal generator further includes a control unit, which is communicatively connected to the switching device and is used to control the switching device to be in an on or off state so as to output a more accurate PWM signal.
[0010] Optionally, the switching device includes a CAN box, which is communicatively connected to the control unit; wherein the digital output pin of the CAN box is connected to the current limiting device and the power amplification device, and the digital ground pin of the CAN box is connected to signal ground. In this way, the CAN box can be used to receive control commands from the control unit and then control the circuit's on / off state, thereby improving the convenience and accuracy of control.
[0011] Optionally, the control element includes a timer and a controller; wherein the controller controls the duty cycle of the PWM signal according to the timer's timing signal. In this way, the state of the switching device can be controlled more accurately through the timer and controller, thereby obtaining a more accurate PWM signal.
[0012] Optionally, the current-limiting device includes a cement resistor. This further enhances circuit protection.
[0013] Optionally, the value of the cement resistor is in the range of 10 ohms to 100K ohms. This allows for a more appropriate loop current when using the CAN box, enabling the output of a PWM signal with high accuracy.
[0014] Secondly, embodiments of this application provide a function signal generator, which includes the PWM signal generator as described in the first aspect. This allows the function signal generator to reduce power loss when outputting a PWM signal with a corresponding duty cycle. Furthermore, since the PWM signal generator has a relatively simple structure and a small overall size, integrating it into the function signal generator can reduce the size of the function signal generator, thereby reducing its space requirements and making it easier to place and move.
[0015] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A circuit diagram of a PWM signal generator provided in an embodiment of this application;
[0018] Figure 2 This is a schematic diagram of the structure of a CAN box provided in an embodiment of this application. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0020] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0021] It should be noted that, unless otherwise specified, the embodiments or technical features in the embodiments of this application may be combined.
[0022] In practice, the inventors discovered that in related technologies, PWM signal generators suffer from significant power loss when outputting PWM signals with corresponding duty cycles. To address this issue, this application provides a PWM signal generator and a function signal generator including the same. Furthermore, the duty cycle is controlled by switching devices to control the circuit's on / off state, and then power loss is reduced by power amplification devices, thereby reducing power loss when outputting PWM signals with corresponding duty cycles.
[0023] The defects in the solutions in the above-mentioned related technologies are all the result of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of this application in the following text should be the inventors' contributions to this application.
[0024] Please refer to Figure 1 The diagram illustrates a circuit diagram of a PWM signal generator according to an embodiment of this application. The PWM signal generator includes switching devices and power amplification devices.
[0025] The first terminal of the switching device is connected to signal ground, and the second terminal is connected to the power supply through a current limiting device; the input terminal of the power amplifier device is connected to the second terminal, and the output terminal of the power amplifier device is used to output a PWM signal.
[0026] Subsequently, when the switching device is in the off state, the circuit is closed, and the output voltage is 0V. That is, the voltage on PWM+ is GND (signal ground), resulting in a low level on PWM+. When the switching device is in the on state, the circuit is open, and the output voltage is the power supply voltage. That is, the voltage on PWM+ is the power supply voltage, resulting in a high level on PWM+. Therefore, the level on PWM+ can be controlled by the state of the switching device.
[0027] It should be noted that the duty cycle of the PWM signal is calculated as follows: Therefore, within one cycle, the duration of the high level on PWM+ can be controlled by switching devices, thereby controlling the duty cycle of the PWM signal.
[0028] Furthermore, this application adds a power amplification device, thereby enabling the PWM signal generator to reduce power loss when outputting a PWM signal with a corresponding duty cycle.
[0029] In some alternative implementations, the PWM signal generator also includes a control unit that is communicatively connected to the switching device and is used to control the switching device to be in an on or off state.
[0030] In some applications, the controller can predetermine the duty cycle and period, and then further determine the corresponding high-level duration. This allows the controller to control the state of the switching device based on the high-level duration and period, thus obtaining a PWM signal with the corresponding duty cycle. For example, if the controller determines the high-level duration to be 60 milliseconds and the period to be 100 milliseconds, it can control the switching device to first be on for 60 milliseconds and then off for 40 milliseconds, thereby obtaining a PWM signal with the corresponding duty cycle.
[0031] The duty cycle and period time mentioned above can be corresponding data input by the user. In some application scenarios, the user can input the frequency of the PWM signal, and the controller can then determine the corresponding period time based on the frequency.
[0032] The aforementioned control unit can be, for example, a microcontroller or a field-programmable gate array (FPGA). Alternatively, the control unit can also be a host computer, which can implement control based on internal software programs. This application does not impose any limitations on this.
[0033] In this implementation, the state of the switching device can be controlled by the controller, which makes it easier to output a more accurate PWM signal.
[0034] In some alternative implementations, the switching device includes a CAN box, which is communicatively connected to the control unit; wherein the digital output pin of the CAN box is connected to the current limiting device and the power amplification device, and the digital ground pin of the CAN box is connected to signal ground.
[0035] The aforementioned CAN box is a hardware device that can communicate with control components via a serial communication protocol (Controller Area Network). Please refer to [link / reference]. Figure 2 It shows a structural schematic diagram of a CAN box provided in an embodiment of this application; as shown Figure 2 As shown, the CAN box includes multiple pins, where pin 8 is a digital output pin and pin 9 is a digital ground pin. The output of digital output pin 8 of the CAN box is the second terminal mentioned above, which is connected to current limiting devices and power amplification devices. The output of digital ground pin 9 of the CAN box is the first terminal mentioned above, which is connected to signal ground.
[0036] It should be noted that, in Figure 2 The CAN box also contains other pin information. For example, pin 1 is an analog input pin, pin 6 is an analog output pin, pin 4 is used to input the digital number 0, and pin 5 is used to input the digital number 1, etc. Those skilled in the art can select the corresponding pins according to actual needs, and this application does not impose any restrictions on this.
[0037] In this implementation, the CAN box can be used to receive control commands from the control unit and then control the circuit to turn on and off, thereby improving the convenience and accuracy of control, and to a certain extent reducing the complexity of the circuit structure, making it easier for users to operate.
[0038] In some alternative implementations, the control element includes a timer and a controller; wherein the controller controls the duty cycle of the PWM signal according to the timer's timing signal.
[0039] In some applications, controllers can use millisecond-level timers to periodically send control signals to switching devices. For example, if the period is determined to be 100 milliseconds and the high-level duration is the last 50 milliseconds of the period, the timer can send a time signal to the controller every 1 millisecond. The controller can then determine whether the time information corresponding to the time signal meets the condition for a high-level input. If not, it can output a signal to turn off the switching device, thus turning the circuit on; if it does, it can output a signal to turn on the switching device, thus turning the circuit off. For example, if the timer outputs the 1st millisecond, since the 1st millisecond is not the last 50 milliseconds of the period, the controller can output the digital "0" to turn off the switching device. If the timer outputs the 51st millisecond, since the 51st millisecond is the last 50 milliseconds of the period, the controller can output the digital "1" to turn on the switching device, thus turning the circuit off. At this point, the current period ends, and the timer can restart outputting time signals from 0, thereby periodically controlling the state of the switching device to obtain a PWM signal with the corresponding duty cycle.
[0040] In this implementation, the state of the switching devices can be controlled more accurately through timers and controllers, thereby obtaining a more accurate PWM signal.
[0041] In some alternative implementations, the current-limiting device includes a cement resistor (i.e., Figure 1 (R1 in the text). Specifically, cement resistors have a larger power capacity and better heat dissipation performance, which is more conducive to protecting the circuit.
[0042] It should be noted that, in addition to cement resistors, current-limiting devices can also be thin-film chip resistors, and users can choose according to their actual needs.
[0043] Furthermore, the CAN box can accept a maximum current of 500 mA. Therefore, the minimum resistance value of the cement resistor can be determined based on the output voltage of the power supply. Specifically, if the minimum output voltage of the power supply is 5V, then the minimum resistance value of the cement resistor can be 10 ohms. Since an excessively large resistance will result in an insufficient loop current, leading to fluctuations or distortion in the PWM signal, the maximum value of the cement resistor can be set at 100K ohms. Therefore, the range of the cement resistor value can be from 10 ohms to 100K ohms. This way, when using the CAN box, a suitable loop current can be obtained to output a PWM signal with high accuracy.
[0044] In some applications, the power supply mentioned above can be a regulated power supply, for example. This allows the output voltage to remain constant, thus mitigating PWM signal distortion or errors caused by unstable power supply voltage and improving the accuracy of the PWM signal to some extent.
[0045] In some alternative implementations, the power amplifier device includes a first resistor R2, a second resistor R3, and an operational amplifier; wherein the positive input terminal of the operational amplifier is connected to the second terminal, the negative input terminal of the power amplifier device is connected to the power supply through the first resistor R2 and grounded through the second resistor R3, and the output terminal of the operational amplifier is used to output a PWM signal.
[0046] The first resistor R2 and the second resistor R3 mentioned above can also be, for example, cement resistors, thin film chip resistors, etc., and this application does not limit them.
[0047] Furthermore, the first resistor R2 and the second resistor R3 mentioned above can be used to determine the closed-loop gain of the operational amplifier; in addition, the second resistor R3 can also provide appropriate feedback, thereby improving the oscillation or instability of the circuit.
[0048] Furthermore, this implementation leverages the advantages of operational amplifiers—high input impedance and low output impedance—to reduce power loss. Specifically, when the operational amplifier is powered, its higher input impedance results in a smaller current shunt, thus minimizing the impact on its input voltage and improving the integrity of the PWM signal. When the operational amplifier is powered, its lower internal resistance results in a smaller voltage division, minimizing the impact on its output voltage and thus improving its load-carrying capacity and reducing power loss during circuit operation.
[0049] Therefore, the above-mentioned structure of the power amplifier device can improve the load-carrying capacity of the external output and reduce the power loss during circuit operation.
[0050] In some applications, the output voltage of the power supply often fluctuates between 0V and the output voltage of the power supply due to factors such as wires and resistance, which results in poor accuracy of the PWM signal.
[0051] Therefore, in these application scenarios, the resistance values of the first resistor R2 and the second resistor R3 can be set to be the same. This serves as a voltage divider, using half of the power supply voltage as the reference voltage for the negative input terminal of the operational amplifier. This allows the operational amplifier to accurately use the voltage fluctuations between 0V and the reference voltage, as well as the voltage fluctuations between the reference voltage and the power supply voltage, for the output PWM signal (that is, to accurately use the voltage fluctuations between 0V and the output voltage of the power supply for the output PWM signal), thereby improving the accuracy of the PWM signal.
[0052] Furthermore, the input stage transistors of operational amplifiers are often not ideal transistors, and they typically have small input bias currents. These currents will generate voltage drops through the input resistance, which will also introduce errors.
[0053] Therefore, a feedback network can be formed using the first resistor R2 and the second resistor R3. Setting the values of the first resistor R2 and the second resistor R3 to be the same ensures that the negative feedback loop of the operational amplifier is balanced. This balance helps reduce the impact of the operational amplifier's bias current on the output PWM signal. Furthermore, identical resistor values also help improve circuit stability and reduce signal distortion or instability caused by differences in resistor values.
[0054] Therefore, setting the resistance values of the first resistor R2 and the second resistor R3 to be the same helps to improve the accuracy of the output PWM signal.
[0055] In some optional implementations, the values of the first resistor R2 and the second resistor R3 range from 10K ohms to 100K ohms, thereby reducing the impact of bias current on the PWM signal and improving the accuracy of the PWM signal. Additionally, this approach is more suitable for applications controlled via a CAN box.
[0056] It should be noted that the PWM signal generator provided in this application has a relatively simple structure and a small overall size, which effectively reduces the space occupied and improves the portability of the PWM signal generator.
[0057] Based on the same concept, this application also provides a function signal generator, which may include the PWM signal generator as described above.
[0058] Furthermore, the aforementioned function signal generator can control the duty cycle by switching the circuit on and off using switching devices, and then reduce power loss through power amplification devices, thereby reducing power loss when outputting a PWM signal with the corresponding duty cycle.
[0059] In addition, the structure of the PWM signal generator provided in this application is relatively simple, so the overall size is small. After integrating it into the function signal generator, the size of the function signal generator can be reduced, thereby reducing the space occupied and making it easier to place and move the function signal generator.
[0060] It should be noted that the above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A PWM signal generator, characterized in that, include: A switching device, wherein the first terminal of the switching device is connected to signal ground, and the second terminal is connected to the power supply through a current limiting device; A power amplifier device, wherein the input terminal of the power amplifier device is connected to the second terminal, and the output terminal of the power amplifier device is used to output a PWM signal.
2. The PWM signal generator according to claim 1, characterized in that, The power amplification device includes a first resistor, a second resistor, and an operational amplifier; The positive input terminal of the operational amplifier is connected to the second terminal, the negative input terminal of the power amplifier is connected to the power supply through the first resistor and grounded through the second resistor, and the output terminal of the operational amplifier is used to output a PWM signal.
3. The PWM signal generator according to claim 2, characterized in that, The first resistor and the second resistor have the same resistance value.
4. The PWM signal generator according to any one of claims 2-3, characterized in that, The values of the first resistor and the second resistor are in the range of 10K ohms to 100K ohms.
5. The PWM signal generator according to claim 1, characterized in that, Also includes: A control element, which is communicatively connected to the switching device, is used to control the switching device to be in an open or closed state.
6. The PWM signal generator according to claim 5, characterized in that, The switching device includes a CAN box, which is communicatively connected to the control unit. The digital output pin of the CAN box is connected to the current limiting device and the power amplification device, and the digital ground pin of the CAN box is connected to the signal ground.
7. The PWM signal generator according to claim 6, characterized in that, The control components include a timer and a controller; The controller controls the duty cycle of the PWM signal based on the timer's timing signal.
8. The PWM signal generator according to claim 6, characterized in that, The current-limiting device includes a cement resistor.
9. The PWM signal generator according to claim 8, characterized in that, The value range of the cement resistance is 10 ohms to 100K ohms.
10. A function signal generator, characterized in that, Includes the PWM signal generator as described in any one of claims 1-9.