CN110994989A - Interface circuit - Google Patents
Interface circuit Download PDFInfo
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- CN110994989A CN110994989A CN201911415989.1A CN201911415989A CN110994989A CN 110994989 A CN110994989 A CN 110994989A CN 201911415989 A CN201911415989 A CN 201911415989A CN 110994989 A CN110994989 A CN 110994989A
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- circuit
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- control unit
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
Abstract
The invention discloses an interface circuit which comprises a micro control unit, an electronic switch circuit, a filter circuit, a voltage follower circuit and a power supply circuit. The pulse width modulation signal sent by the micro control unit is converted into a pulse width modulation signal of a first preset voltage through the electronic switch circuit, then the pulse width modulation signal is filtered by the filter circuit to obtain a direct current voltage of a second preset voltage, and finally the direct current voltage of the second preset voltage is obtained through the voltage stabilization of the voltage follower circuit. In the embodiment of the invention, after the pulse width modulation signal is converted by the electronic switch circuit, the direct current voltage is generated by the filter circuit and the voltage follower circuit.
Description
Technical Field
The present invention relates to a circuit, and more particularly, to an interface circuit.
Background
PWM (Pulse width modulation) is an analog control method, and modulates the bias of the base of a transistor or the gate of a MOS transistor according to the change of a corresponding load to change the conduction time of the transistor or the MOS transistor, thereby changing the output of a switching regulator. This way the output voltage of the power supply can be kept constant when the operating conditions change, which is a very effective technique for controlling an analog circuit by means of the digital signal of the microprocessor.
In the current regulation interface circuit, an MCU is usually adopted to control a DA chip to output an analog voltage value through PWM, and then a 1-10V direct current voltage is generated through a voltage amplifying circuit and a voltage following circuit. This method, while highly accurate, is also relatively costly.
Disclosure of Invention
The embodiment of the invention provides an interface circuit, which aims to solve the problem that the cost is higher when a DA chip is adopted in the prior art.
In order to solve the technical problem, the invention is realized as follows:
there is provided an interface circuit, comprising: the device comprises a micro control unit, an electronic switch circuit, a filter circuit, a voltage following circuit and a power supply circuit;
the output end of the micro control unit is connected with the first input end of the electronic switch circuit, and the electronic switch circuit converts the pulse width modulation signal output by the micro control unit into a pulse width modulation signal with a first preset voltage;
the output end of the electronic switch circuit is connected with the input end of the filter circuit, and the filter circuit filters a pulse width modulation signal of a first preset voltage output by the electronic switch circuit to obtain a direct current voltage of a second preset voltage;
the output end of the filter circuit is connected with the first input end of the voltage follower circuit, and the voltage follower circuit is used for stabilizing the filtered direct-current voltage of the second preset voltage;
the output end of the power supply circuit is respectively connected with the first input end of the micro control unit, the second input end of the electronic switch circuit and the second input end of the voltage follower circuit, and the power supply circuit supplies power to the micro control unit, the electronic switch circuit and the voltage follower circuit.
In the embodiment of the invention, the pulse width modulation signal sent by the micro control unit is converted into the pulse width modulation signal of the first preset voltage through the electronic switch circuit, then the pulse width modulation signal is filtered by the filter circuit to obtain the direct current voltage of the second preset voltage, and finally the direct current voltage of the second preset voltage is obtained through the voltage stabilization of the voltage follower circuit. In the embodiment of the invention, after the pulse width modulation signal is converted by the electronic switch circuit, the direct current voltage is generated by the filter circuit and the voltage follower circuit.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of an interface circuit provided by one embodiment of the present invention;
FIG. 2 is a schematic diagram of another interface circuit provided by one embodiment of the present invention;
FIG. 3 is a circuit schematic of an electronic switching circuit according to one embodiment of the present invention;
FIG. 4 is a circuit schematic of a filter circuit according to an embodiment of the present invention;
FIG. 5 is a circuit schematic of a voltage follower circuit according to an embodiment of the present invention;
FIG. 6 is a circuit schematic of an output voltage feedback circuit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of another interface circuit provided by an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides an interface circuit which can be a 1-10V dimming interface circuit and can be used for regulating voltage for lamps or other electric equipment. Specifically, the electronic switching circuit can be controlled by a PWM signal with a certain duty ratio output by an MCU (micro controller Unit), and then a dc voltage of 1-10V is generated by a filter circuit and a voltage follower circuit to adjust the voltage of the electric device. With the above-described conventional electronic device, the cost of the circuit can be reduced. The output voltage feedback circuit can also be utilized to feed back the voltage value output by the voltage follower circuit to the MCU, and the MCU adjusts the duty ratio of the PWM signal through the voltage value fed back by the voltage follower circuit so that the output voltage is more stable and the precision is higher.
Fig. 1 is a schematic diagram of an interface circuit according to an embodiment of the present invention. As shown, the interface circuit may include: the circuit comprises a micro control unit, an electronic switch circuit, a filter circuit, a voltage follower circuit and a power supply circuit.
The output end of the micro control unit is connected with the first input end of the electronic switch circuit, and the electronic switch circuit converts the pulse width modulation signal output by the micro control unit into a pulse width modulation signal with a first preset voltage.
The output end of the electronic switch circuit is connected with the input end of the filter circuit, and the filter circuit filters the pulse width modulation signal of the first preset voltage output by the electronic switch circuit to obtain the direct current voltage of the second preset voltage.
The output end of the filter circuit is connected with the first input end of the voltage follower circuit, and the voltage follower circuit is used for stabilizing the filtered direct-current voltage of the second preset voltage.
The output end of the power supply circuit is respectively connected with the first input end of the micro control unit, the second input end of the electronic switch circuit and the second input end of the voltage following circuit, and the power supply circuit supplies power to the micro control unit, the electronic switch circuit and the voltage following circuit.
In the embodiment of the invention, firstly, a pulse width modulation signal sent by a micro control unit is converted into a pulse width modulation signal of a first preset voltage through an electronic switch circuit, then, a direct current voltage of a second preset voltage is obtained after filtering through a filter circuit, and finally, the direct current voltage of the second preset voltage is obtained through voltage stabilization of a voltage follower circuit. In the embodiment of the invention, after the pulse width modulation signal is converted by the electronic switch circuit, the direct current voltage is generated by the filter circuit and the voltage follower circuit, and compared with the prior art in which a DA chip is required, the interface circuit provided by the embodiment of the invention only adopts some conventional electronic devices, so that the cost is relatively low.
The MCU can output PWM signals and also has the function of AD acquisition (converting analog signals into digital signals).
In one possible embodiment of the present invention, as shown in fig. 2, a schematic diagram of another interface circuit provided by the present invention is shown. As shown, the interface circuit may further include: and an output voltage feedback circuit.
The input end of the output voltage feedback circuit is connected with the output end of the voltage follower circuit, the output end of the output voltage feedback circuit is connected with the second input end of the micro control unit, and the output voltage feedback circuit feeds back the direct current voltage of the second preset voltage output by the voltage follower circuit after the voltage follower circuit is stabilized to the micro control unit.
In the embodiment of the invention, the output voltage feedback circuit can feed back the output voltage of the voltage follower circuit to the micro control unit, and the micro control unit adjusts the duty ratio of the output PWM signal according to the voltage fed back by the output voltage feedback circuit, so that the voltage value output by the circuit is more accurate, and the voltage output precision is ensured. Namely, the interface circuit provided by the invention can reduce the cost and ensure the precision.
In one possible embodiment of the present invention, as shown in fig. 3, a schematic circuit diagram of an electronic switching circuit provided by the present invention is shown. As shown, the electronic switching circuit may include: a switching device, a first resistor R1 and a second resistor R2.
The first end of the switching device is connected with the first end of the first resistor R1, the second end of the switching device is respectively connected with the first end of the second resistor R2 and the input end of the filter circuit, and the third end of the switching device is grounded. The second terminal of the first resistor R1 is connected to the output of the microcontroller unit. A second end of the second resistor R2 is connected to an external power supply terminal.
The external power supply can be an independent power supply or an external power supply. The value of the external power source may be determined according to the actual condition of the circuit, for example, 15V, 12V, and the like, and is not limited herein.
Specifically, the switching device may be a field effect transistor (MOS transistor), a triode, or another switching device with an amplifying function. In fig. 3, a triode is used.
In one embodiment of the present invention, the switching device is a triode. Because the triode can not generate electric arc when in use, the contact safety is higher. The triode plays an amplifying role in the interface circuit provided by the application.
Specifically, the base of the transistor Q is connected to the first end of the first resistor R1, the collectors of the switching devices are respectively connected to the first end of the second resistor R2 and the input end of the filter, and the emitter of the transistor is grounded.
In one embodiment of the present invention, the switching device is a field effect transistor (MOS transistor), and the field effect transistor may be an N-channel type field effect transistor. The MOS pipe is metal (metal), oxide, semiconductor (semiconductor) field effect transistor, has the advantage that input impedance is high, the noise is low, thermal stability is good, and the MOS pipe plays the amplification effect in the interface circuit that this application provided.
Specifically, the gate of the field effect transistor is connected to the first end of the first resistor R1, the drain of the field effect transistor is connected to the first end of the second resistor R2 and the input end of the filter, respectively, and the source of the field effect transistor is grounded.
In a possible embodiment of the present invention, as shown in fig. 4, which is a schematic circuit diagram of a filter circuit provided in the present invention, as shown in the figure, the filter circuit may include: a third resistor R3, a fourth resistor R4, a first capacitor C1 and a second capacitor C2.
A first end of the third resistor R3 is connected to an output terminal of the electronic switch circuit, and a second end of the third resistor R3 is connected to a first end of the fourth resistor R4 and a first end of the first capacitor C1, respectively. The second end of the fourth resistor R4 is connected to the first end of the second capacitor C2 and the first input end of the voltage follower circuit, respectively. The second terminal of the first capacitor C1 is connected to ground. The second terminal of the second capacitor C2 is connected to ground.
In the embodiment of the invention, the filter circuit adopts a two-stage RC filter circuit, so that the filter effect is better.
In one possible embodiment of the present invention, as shown in fig. 5, a circuit diagram of a voltage follower circuit provided by the present invention is shown. As shown, the voltage follower circuit may include: an operational amplifier U1, a fifth resistor R5, and a sixth resistor R6.
The non-inverting input terminal of the operational amplifier U1 is connected to the first terminal of the fifth resistor R5, the inverting input terminal of the operational amplifier U1 is connected to the first terminal of the sixth resistor R6, the first power input terminal of the operational amplifier U1 is connected to an external power supply terminal, the second power input terminal of the operational amplifier U1 is grounded, and the output terminal of the operational amplifier U1 is connected to the power consumption terminal, the input terminal of the output voltage feedback circuit, and the second terminal of the sixth resistor R6, respectively. A second terminal of the fifth resistor R5 is connected to an output terminal of the filter circuit.
In the embodiment of the invention, the output end of the voltage follower circuit is directly connected with the power utilization end, and the operational amplifier is adopted, so that the output voltage of the voltage follower circuit is more stable, and meanwhile, the output resistance is lower, so that the loading capacity of the circuit is stronger.
In one possible embodiment of the present invention, as shown in fig. 6, a circuit diagram of an output voltage feedback circuit provided in the present invention is shown. As shown, the output voltage feedback circuit may include: a seventh resistor R7 and an eighth resistor R8.
A first end of the seventh resistor R7 is connected to the output end of the voltage follower circuit, a second end of the seventh resistor R7 is connected to a first end of the eighth resistor R8 and a second input end of the micro control unit, respectively, and a second end of the eighth resistor R8 is grounded.
In the embodiment of the invention, the output voltage of the voltage follower circuit is fed back to the MCU in a mode of connecting two resistors in parallel, the MCU acquires and detects the voltage value output by the output voltage feedback circuit through AD, and the MCU adjusts the duty ratio of the output PWM signal according to the voltage value, so that the output voltage is more accurate.
In a possible embodiment of the present invention, as shown in fig. 7, which is a schematic diagram of another interface circuit provided by the present invention, as shown in the figure, the power supply circuit may include: voltage stabilizing circuit and little the control unit power supply circuit.
The output end of the voltage stabilizing circuit is respectively connected with the second input end of the electronic switch circuit, the second input end of the voltage follower circuit and the input end of the micro-control unit power supply circuit. The output end of the micro control unit power supply circuit is connected with the first input end of the micro control unit.
In the embodiment of the invention, the voltage stabilizing circuit can provide electric energy for the electronic switch circuit, the voltage follower circuit and the micro-control unit power supply circuit and is a power supply of the whole circuit. The voltage value of the voltage regulator circuit may be determined according to the actual conditions of the circuit, such as 15V, 12V, and the like.
The micro-control unit power supply circuit provides electric energy for the micro-control unit, and the provided voltage value can be determined according to the requirement of the micro-control unit.
Specifically, the electronic switch circuit is a 12V electronic switch circuit so as to output a voltage of 1-10V to the power consumption end, and correspondingly, the voltage stabilizing circuit can be a 12V voltage stabilizing circuit and can provide the voltage for the electronic switch circuit without changing the size of the voltage finger.
The electronic devices adopted in the embodiment of the invention are common electronic devices, have lower cost, are used for providing variable voltage for electric devices (such as LED lamps), and can save the cost of the whole device. And an output voltage feedback circuit is adopted to adjust the output voltage in real time, so that the precision of the whole output voltage can be ensured.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. An interface circuit, comprising: the device comprises a micro control unit, an electronic switch circuit, a filter circuit, a voltage following circuit and a power supply circuit;
the output end of the micro control unit is connected with the first input end of the electronic switch circuit, and the electronic switch circuit converts the pulse width modulation signal output by the micro control unit into a pulse width modulation signal with a first preset voltage;
the output end of the electronic switch circuit is connected with the input end of the filter circuit, and the filter circuit filters a pulse width modulation signal of a first preset voltage output by the electronic switch circuit to obtain a direct current voltage of a second preset voltage;
the output end of the filter circuit is connected with the first input end of the voltage follower circuit, and the voltage follower circuit is used for stabilizing the filtered direct-current voltage of the second preset voltage;
the output end of the power supply circuit is respectively connected with the first input end of the micro control unit, the second input end of the electronic switch circuit and the second input end of the voltage follower circuit, and the power supply circuit supplies power to the micro control unit, the electronic switch circuit and the voltage follower circuit.
2. The interface circuit of claim 1, wherein the interface circuit further comprises: an output voltage feedback circuit;
the input end of the output voltage feedback circuit is connected with the output end of the voltage follower circuit, the output end of the output voltage feedback circuit is connected with the second input end of the micro control unit, and the output voltage feedback circuit feeds back the direct current voltage of the second preset voltage output by the stabilized voltage follower circuit to the micro control unit.
3. The interface circuit of claim 1, wherein the electronic switching circuit comprises: a switching device, a first resistor and a second resistor;
a first end of the switching device is connected with a first end of the first resistor, a second end of the switching device is respectively connected with a first end of the second resistor and an input end of the filter circuit, and a third end of the switching device is grounded;
the second end of the first resistor is connected with the output end of the micro control unit;
and the second end of the second resistor is connected with an external power supply terminal.
4. The interface circuit of claim 3, wherein the switching device comprises: a field effect transistor or a triode.
5. The interface circuit of claim 1, wherein the filtering circuit comprises: the circuit comprises a third resistor, a fourth resistor, a first capacitor and a second capacitor;
the first end of the third resistor is connected with the output end of the electronic switch circuit, and the second end of the third resistor is respectively connected with the first end of the fourth resistor and the first end of the first capacitor;
a second end of the fourth resistor is respectively connected with a first end of the second capacitor and a first input end of the voltage follower circuit;
the second end of the first capacitor is grounded;
and the second end of the second capacitor is grounded.
6. The interface circuit of claim 2, wherein the voltage follower circuit comprises: the operational amplifier, the fifth resistor and the sixth resistor;
the non-inverting input end of the operational amplifier is connected with the first end of the fifth resistor, the inverting input end of the operational amplifier is connected with the first end of the sixth resistor, the first power supply input end of the operational amplifier is connected with an external power supply terminal, the second power supply input end of the operational amplifier is grounded, and the output end of the operational amplifier is respectively connected with the power utilization end, the input end of the output voltage feedback circuit and the second end of the sixth resistor;
and the second end of the fifth resistor is connected with the output end of the filter circuit.
7. The interface circuit of claim 2, wherein the output voltage feedback circuit comprises: a seventh resistor and an eighth resistor;
the first end of the seventh resistor is connected with the output end of the voltage follower circuit, and the output end of the seventh resistor is respectively connected with the first end of the eighth resistor and the second input end of the micro control unit;
and the second end of the eighth resistor is grounded.
8. The interface circuit of claim 1, wherein the power supply circuit comprises: the voltage stabilizing circuit and the micro control unit power supply circuit;
the output end of the voltage stabilizing circuit is respectively connected with the second input end of the electronic switch circuit, the second input end of the voltage follower circuit and the input end of the micro-control unit power supply circuit;
the output end of the micro control unit power supply circuit is connected with the first input end of the micro control unit.
9. The interface circuit of claim 8, wherein the electronic switching circuit is a 12V electronic switching circuit.
10. The interface circuit of claim 8, wherein the regulator circuit is a 12V regulator circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911415989.1A CN110994989A (en) | 2019-12-31 | 2019-12-31 | Interface circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911415989.1A CN110994989A (en) | 2019-12-31 | 2019-12-31 | Interface circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110994989A true CN110994989A (en) | 2020-04-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911415989.1A Pending CN110994989A (en) | 2019-12-31 | 2019-12-31 | Interface circuit |
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| Country | Link |
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| CN (1) | CN110994989A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112953478A (en) * | 2021-03-19 | 2021-06-11 | 苏州贝昂科技有限公司 | Switch controller and electronic equipment |
| CN114460999A (en) * | 2022-01-04 | 2022-05-10 | 珠海格力电器股份有限公司 | Adjustable circuit, controller and electronic equipment |
-
2019
- 2019-12-31 CN CN201911415989.1A patent/CN110994989A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112953478A (en) * | 2021-03-19 | 2021-06-11 | 苏州贝昂科技有限公司 | Switch controller and electronic equipment |
| CN112953478B (en) * | 2021-03-19 | 2022-06-07 | 苏州贝昂科技有限公司 | Switch controller and electronic equipment |
| CN114460999A (en) * | 2022-01-04 | 2022-05-10 | 珠海格力电器股份有限公司 | Adjustable circuit, controller and electronic equipment |
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