Low-cost simple digital-to-analog conversion DA expansion circuit
The PWM signal is output through the MCU controller, combined with filtering and isolation circuit, multiple DA port functions are realized in the case of limited MCU interface, solving the problem of increasing hardware costs caused by insufficient MCU interface, and providing a low-cost and rapid development solution plan.
Patent Information
- Application Number
- CN202420933764.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2034-04-30
AI Technical Summary
When existing digital-to-analog converter devices have limited MCU interfaces, when adding external DA chips to implement multiple DA ports, hardware cost and development time will increase, and the lack of redundant interfaces cannot be added to external DA chips.
A low-cost simple digital-to-analog conversion DA expansion circuit is designed, using the MCU controller to output the PWM signal, and the same function of the DA chip is realized through the filtering circuit and the isolation circuit, reducing hardware cost and development time, providing multiple DA ports, avoiding the increase of external DA chip and too many interfaces.
It realizes low-cost and rapid development when the number of MCU controllers and interfaces is limited, provides multiple DA signal selection, reduces hardware investment and costs, avoids increasing hardware costs, and meets the needs of multiple DA ports.
Smart Images
Figure CN222301805U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of digital-to-analog conversion, in particular to a low-cost simple digital-to-analog conversion DA expansion circuit. Background Art
[0002] Analog-to-digital converter, also known as A / D converter, is a device that converts continuous analog signals into discrete digital signals. The most common digital-to-analog converter converts parallel binary digital quantities into DC voltage or DC current. It is often used as the output channel of process control computer systems and connected to actuators to achieve automatic control of production processes. Digital-to-analog converter circuits are also used in the design of analog-to-digital converters using feedback technology. DAC is mainly composed of digital registers, analog electronic switches, bit weight networks, summing operational amplifiers and reference voltage sources (or constant current sources). Each digital number stored in the digital register is used to control the analog electronic switch of the corresponding bit, so that the bit with a digital number of 1 generates a current value proportional to its bit weight on the bit weight network, and then the operational amplifier sums the current values and converts them into voltage values.
[0003] The existing digital-to-analog conversion DA is very mature, but the conventional MCU has only two DA ports. When multiple DAs are needed, an external DA chip can only be added, which will increase the hardware cost accordingly. At the same time, when the MCU interface is not enough, there is no extra interface to add an external DA chip. Utility Model Content
[0004] The utility model aims to solve the shortcomings in the prior art and proposes a low-cost simple digital-to-analog conversion DA expansion circuit.
[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a low-cost and simple digital-to-analog conversion DA expansion circuit, including an MCU controller, a filtering circuit, and an isolation circuit. The MCU controller is connected to resistor 1, the resistor 1 is connected to the G pole of a power tube, the D pole of the power tube is connected to resistor 2, one end of the resistor 2 is connected to a control power supply, the S pole of the power tube is connected to resistor 3, the resistor 3 is connected to ground, one end of the resistor 3 is connected to resistor 1, the D pole of the power tube is connected to the A end of a control chip, the B end of the control chip is connected to ground, and the A end of the control chip is connected to the C end of the control chip.
[0006] As a further description of the above technical solution:
[0007] The filtering circuit includes a resistor four, the resistor four is connected to a resistor five, one end of the resistor four is connected to a capacitor one, one end of the resistor five is connected to a capacitor two, and the capacitor two is connected to the capacitor one.
[0008] As a further description of the above technical solution:
[0009] The isolation circuit comprises an isolation chip, the A end of the isolation chip is connected to the resistor 5, and the C end of the isolation chip is connected to the B end of the isolation chip.
[0010] As a further description of the above technical solution:
[0011] The C terminal of the isolation chip is connected to a resistor six, and the resistor six is connected to an output signal.
[0012] As a further description of the above technical solution:
[0013] One end of the resistor 4 is connected to the A end of the control chip, and the capacitor 1 is connected to the ground.
[0014] As a further description of the above technical solution:
[0015] The voltage of the control power supply is 12V.
[0016] As a further description of the above technical solution:
[0017] The isolation circuit has a driving capability.
[0018] The utility model has the following beneficial effects:
[0019] 1. In the utility model, the PWM signal output by the simple device and the MCU controller realizes the same function as the DA chip, and the control is simple, which can well reduce the hardware cost and development time. When the number of MCU controllers and interfaces is limited and there are more demands for the digital-to-analog conversion DA signal, it provides more choices for design and development personnel, reduces the hardware investment and cost increase.
[0020] 2. In the utility model, the MCU controller sends out a PWM signal to drive the power tube through resistor 1, and the filter circuit is filtered by resistor 4, resistor 5, capacitor 1, and capacitor 2, and the isolation circuit is finally output through resistor 6 to provide the required execution unit. There is no need to add an external DA chip, too many expansion interfaces, and too much hardware cost, and multiple DA ports can be expanded externally. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a schematic diagram of a low-cost and simple digital-to-analog conversion DA expansion circuit proposed by the utility model;
[0022] Figure 2 This is a principle block diagram of a low-cost and simple digital-to-analog conversion DA expansion circuit proposed by the utility model;
[0023] Figure 3Part of the principle of a low-cost and simple digital-to-analog conversion DA expansion circuit proposed by the utility model Figure 1 ;
[0024] Figure 4 Part of the principle of a low-cost and simple digital-to-analog conversion DA expansion circuit proposed by the utility model Figure 2 .
[0025] Legend:
[0026] 1. MCU controller; 2. Resistor 1; 3. Power tube; 4. Resistor 2; 5. Control power supply; 6. Resistor 3; 7. Grounding; 8. Control chip; 9. Filter circuit; 10. Isolation circuit; 11. Resistor 4; 12. Resistor 5; 13. Capacitor 1; 14. Capacitor 2; 15. Isolation chip; 16. Resistor 6; 17. Output signal. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0028] Reference Figure 1-Figure 4 The utility model provides an embodiment: a low-cost simple digital-to-analog conversion DA expansion circuit, including an MCU controller 1, a filtering circuit 9, and an isolation circuit 10. The MCU controller 1 is connected to a resistor 2, the resistor 2 is connected to the G pole of a power tube 3, the D pole of the power tube 3 is connected to a resistor 4, one end of the resistor 4 is connected to a control power supply 5, the S pole of the power tube 3 is connected to a resistor 3 6, the resistor 3 6 is connected to a ground 7, one end of the resistor 3 6 is connected to the resistor 2, the D pole of the power tube 3 is connected to the A end of a control chip 8, the B end of the control chip 8 is connected to the ground 7, and the A end of the control chip 8 is connected to the C end of the control chip 8. Simple devices and PWM signals output by the MCU controller 1 are used to achieve the same function as the DA chip. The control is simple, which can well reduce hardware costs and development time. When the MCU controller 1 and the number of interfaces are limited, when there are more requirements for digital-to-analog conversion DA signals, more choices are provided to design and development personnel, reducing hardware investment and cost increases.
[0029] The filter circuit 9 includes a resistor 4 11, the resistor 4 11 is connected to a resistor 5 12, one end of the resistor 4 11 is connected to a capacitor 1 13, one end of the resistor 5 12 is connected to a capacitor 2 14, and the capacitor 2 14 is connected to the capacitor 1 13. The isolation circuit 10 includes an isolation chip 15, the A end of the isolation chip 15 is connected to the resistor 5 12, the C end of the isolation chip 15 is connected to the B end of the isolation chip 15, the C end of the isolation chip 15 is connected to a resistor 6 16, the resistor 6 16 is connected to the output signal 17, and one end of the resistor 4 11 is connected to the output signal 17 of the control chip 8. At the A end, capacitor 13 is connected to ground 7, the voltage of the control power supply 5 is 12V, and the isolation circuit 10 has driving capability. The MCU controller 1 sends a PWM signal to drive the power tube 3 through the resistor 12, and the resistor 4 11, the resistor 5 12, the capacitor 1 13, and the capacitor 2 14 in the filter circuit 9 are used for coordinated filtering, and the isolation circuit 10 finally outputs an analog signal through the resistor 6 16 and provides it to the required execution unit. There is no need to add an external DA chip, too many expansion interfaces, or too much hardware cost, and multiple DA ports can be expanded externally.
[0030] Working principle: MCU controller 1 sends out PWM signal to drive power tube 3 through resistor 1 2. When PWM is full high, power tube 3 is fully turned on. At this time, the D pole of power tube 3 is completely pulled down. After passing through the following filter circuit 9 (including resistor 4 11, resistor 5 12, capacitor 1 13, capacitor 2 14), isolation circuit 10, it is finally output as 0V through resistor 6 16. When the PWM signal is full low, the power tube 3 is in the off state. The D pole voltage of power tube 3 is determined by control chip 8. Control chip 8 directly embeds the voltage of this point as 2.5V. After passing through the following filter circuit 9 (including resistor 4 11, resistor 5 12, capacitor 1 13, capacitor 2 14), isolation circuit 10, it is finally output as 2.5V through resistor 6 16. The maximum output of this circuit is 2.5V (the maximum output voltage can be determined by adjusting the voltage divider parameters as needed). When the PWM duty cycle is adjusted from 0 to 100%, the power tube 3 will adjust the conduction time according to the size of the PWM duty cycle, and then the power The D pole of the rate tube 3 will obtain an equivalent PWM square wave voltage according to the PWM signal. The square wave voltage will be converted into a stable analog voltage after passing through the subsequent filtering circuit 9 (including resistor four 11, resistor five 12, capacitor one 13, and capacitor two 14). Then, the signal is isolated through the isolation circuit 10, and the driving ability of the previous analog signal can be increased. Finally, the output signal 17 is output through the resistor six 16. The final output voltage range is 0-2.5V. The PWM signal output by the simple device and the MCU controller 1 realizes the same function as the DA chip. There is no need to add an external DA chip, too many expansion interfaces, and too much hardware cost. Multiple DA ports can be expanded externally, and the control is simple. It can well reduce hardware cost and development time. When the MCU controller 1 and the number of interfaces are limited, there are more demands for digital-to-analog conversion DA signals, which provides more choices for design and development personnel and reduces hardware investment and cost increase.
[0031] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A low-cost and simple digital-to-analog conversion (DA) expansion circuit, comprising an MCU controller (1), a filter circuit (9), and an isolation circuit (10), characterized in that: The MCU controller (1) is connected to a resistor 1 (2), the resistor 1 (2) is connected to the G pole of a power tube (3), the D pole of the power tube (3) is connected to a resistor 2 (4), one end of the resistor 2 (4) is connected to a control power supply (5), the S pole of the power tube (3) is connected to a resistor 3 (6), the resistor 3 (6) is connected to a ground (7), one end of the resistor 3 (6) is connected to the resistor 1 (2), the D pole of the power tube (3) is connected to the A end of a control chip (8), the B end of the control chip (8) is connected to the ground (7), and the A end of the control chip (8) is connected to the C end of the control chip (8).
2. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 1, characterized in that: The filter circuit (9) comprises a resistor four (11), the resistor four (11) is connected to a resistor five (12), one end of the resistor four (11) is connected to a capacitor one (13), one end of the resistor five (12) is connected to a capacitor two (14), and the capacitor two (14) is connected to the capacitor one (13).
3. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 1, characterized in that: The isolation circuit (10) comprises an isolation chip (15), the A end of the isolation chip (15) is connected to the resistor five (12), and the C end of the isolation chip (15) is connected to the B end of the isolation chip (15).
4. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 3 is characterized in that: The C terminal of the isolation chip (15) is connected to a resistor six (16), and the resistor six (16) is connected to an output signal (17).
5. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 2, characterized in that: One end of the resistor 4 (11) is connected to the A end of the control chip (8), and the capacitor 1 (13) is connected to the ground (7).
6. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 1, characterized in that: The voltage of the control power supply (5) is 12V.
7. The low-cost and simple digital-to-analog conversion (DA) expansion circuit according to claim 1, characterized in that: The isolation circuit (10) has driving capability.