Anti-interference driving device applied to high-power bridge circuit

Abstract

The invention discloses an anti-interference driving device and system applied to a high-power bridge circuit, and the device comprises a comparator which is used for receiving an initial driving signal transmitted by a control chip and reversely converting the initial driving signal into a reverse driving signal, and a voltage signal is converted into a reverse on-off current signal through a voltage-to-current circuit. The method comprises the following steps: firstly, enabling a current signal to pass through a strong interference area on a mainboard, then, at the front end of a driving chip, re-converting the current signal into an intermediate driving signal with the same voltage as a reverse driving signal through a current-to-voltage circuit, and finally, outputting a target driving signal with a corresponding voltage amplitude through the driving chip so as to drive a switching tube. By using the anti-interference characteristic of the current signal, the problem of electromagnetic interference caused by the high-frequency change of the floating voltage of the bridge circuit is effectively solved. By adding the signal conversion circuit at the key position, the optimization of the existing driving circuit is realized, and the whole circuit structure does not need to be greatly changed.

Description

Technical Field

[0001] This application relates to the technical field of high-power bridge circuits, and in particular to an anti-interference driving device applied to high-power bridge circuits. Background Art

[0002] A high-power bridge circuit refers to a bridge circuit that can process high-power signals. One of its characteristics is that the floating ground voltage on the high-voltage side of the bridge circuit will continuously change with the high-frequency on-off of the switching tube, thereby generating a changing electric field. This electric field will excite a magnetic field, and the changing magnetic field will in turn excite an electric field. Repeating this process forms electromagnetic waves, which will radiate into space and interfere with the surrounding circuits.

[0003] A driving circuit refers to an intermediate circuit located between the main circuit and the control circuit. Its main function is to amplify the signals of the control circuit so that it can drive the switching tube. Generally, it is located near the switching tube. Since the high-frequency on-off of the switching tube in the high-power bridge circuit will cause circuit interference, the driving circuit must have a certain anti-interference ability to ensure the normal turn-on of the switching tube.

[0004] The existing driving circuit is that the control chip issues a driving signal, which finally reaches the switching tube through the driving chip. The entire driving trace goes from the weak-electricity area near the control chip to the strong-electricity area near the switching tube. It is difficult to avoid passing through the floating ground point in the PCB trace on the main board, and it is easily affected by the electromagnetic interference of the high-frequency change of the floating ground voltage, resulting in abnormal driving problems. Summary of the Invention

[0005] The embodiment of this application provides an anti-interference driving device applied to a high-power bridge circuit. By adding a voltage-to-current circuit at the back end of the control chip, a driving signal is transmitted with a current signal having strong anti-interference ability, and when it reaches the front end of the driving chip, the current signal is converted into a voltage signal by a current-to-voltage circuit to enhance the anti-interference ability of the driving loop.

[0006] To solve the above technical problems, the embodiment of this application provides the following technical solutions:

[0007] This application provides an anti-interference driving device applied to a high-power bridge circuit, including:

[0008] A comparator, a voltage-to-current circuit, a current-to-voltage circuit, and a driving circuit;

[0009] The output end of the comparator is connected to the input end of the voltage-to-current circuit, and is used to receive the initial driving signal issued by the control chip and convert it into a reverse driving signal in reverse;

[0010] The output terminal of the voltage-to-current circuit is connected to the input terminal of the current-to-voltage circuit, and is used to convert the reverse drive signal into a reverse on-off current signal;

[0011] The output terminal of the current-to-voltage circuit is connected to the input terminal of the drive chip, and is used to convert the reverse on-off current signal into an intermediate drive signal; the voltage amplitude of the intermediate drive signal is the same as that of the reverse drive signal;

[0012] A drive circuit, which is used to perform voltage conversion on the intermediate drive signal to obtain a target drive signal for driving a switching transistor.

[0013] According to the anti-interference drive device applied to the high-power bridge circuit, the current-to-voltage circuit includes:

[0014] An optocoupler, the cathode of the optocoupler serves as the input terminal of the current-to-voltage circuit, and is used to turn on the current by controlling the cathode voltage to be less than the anode voltage, and is also used to turn off the current by controlling the cathode voltage to be greater than or equal to the anode voltage. Among them, the voltage amplitude of the cathode of the optocoupler is greater than that of the anode to achieve negative voltage turn-off.

[0015] According to the anti-interference drive device applied to the high-power bridge circuit, the voltage-to-current circuit includes:

[0016] The second drive chip is used to enhance the reverse drive signal and then convert it into a reverse on-off current signal.

[0017] According to the anti-interference drive device applied to the high-power bridge circuit, the on-off of the current on the primary side of the optocoupler forms a switchable current signal, which is converted into an intermediate drive signal by the optocoupler, and the intermediate drive signal enters the drive circuit to output a target drive signal.

[0018] According to the anti-interference drive device applied to the high-power bridge circuit, the voltage amplitude of the initial drive signal is in the first voltage range, the intermediate drive signal is in the second voltage range, and the voltage amplitude of the target drive signal is in the third voltage range.

[0019] According to the anti-interference drive device applied to the high-power bridge circuit, the voltage amplitude of the reverse drive signal is in the second voltage range.

[0020] According to the anti-interference drive device applied to the high-power bridge circuit, the voltage-to-current circuit further includes a filter circuit:

[0021] The input end of the filtering circuit is the input end of the voltage-to-current circuit. The output end of the filtering circuit is connected to the input end of the second driving chip. The filtering circuit includes a circuit composed of a resistor and a capacitor, and is used to perform noise filtering on the reverse driving signal in the second voltage range output by the comparator.

[0022] The present application also provides an anti-interference driving system applied to a high-power bridge circuit. The system includes the anti-interference driving device applied to a high-power bridge circuit described in any one of the above.

[0023] The anti-interference driving device applied to a high-power bridge circuit provided by the present application

[0024] By setting a comparator to receive the initial driving signal sent by the control chip and reversely convert it into a reverse driving signal, through the voltage-to-current circuit, the voltage signal is converted into a reverse on-off current signal, and then the current signal passes through the strong interference area on the main board. Then, in front of the driving chip, the current signal is reconverted into an intermediate driving signal with the same voltage as the reverse driving signal through the current-to-voltage circuit. Finally, the target driving signal with the corresponding voltage amplitude is output through the driving chip to drive the switching tube. The present invention utilizes the anti-interference characteristics of the current signal to effectively solve the electromagnetic interference problem caused by the high-frequency change of the floating ground voltage in the bridge circuit. By adding signal conversion circuits at key positions, the optimization of the existing driving circuit is realized without significantly modifying the overall circuit structure. The present invention successfully solves the technical problem that the driving signal in the high-power bridge circuit is vulnerable to interference, improves the stability and reliability of the circuit, and has important practical value.

[0025] By controlling the cathode voltage to be less than the anode voltage to turn on the current, and also used to control the cathode voltage to be greater than or equal to the anode voltage to turn off the current. Among them, the amplitude of the cathode voltage of the optocoupler is greater than the anode voltage to achieve negative voltage turn-off, making the optocoupler more reliable when turned off, further enhancing the stability of the signal and not being easily affected by external electromagnetic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following will make the technical solutions and other beneficial effects of the present application obvious by describing the specific embodiments of the present application in detail with reference to the drawings.

[0027] Figure 1 It is a schematic structural diagram of an anti-interference driving device applied to a high-power bridge circuit provided by an embodiment of the present application;

[0028] Figure 2 It is a schematic circuit structure diagram of another anti-interference driving device applied to a high-power bridge circuit provided by an embodiment of the present application;

[0029] Figure 3This is a comparative schematic diagram of the effect of the anti-interference drive device applied to the high-power bridge circuit provided by the embodiments of the present application. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention 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 the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The terms "first", "second", "third", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0032] The embodiments of the present application provide an anti-interference drive system applied to a high-power bridge circuit. Figure 1 This is a schematic structural diagram of an anti-interference drive device provided by the embodiments of the present application. To facilitate the understanding of the function of the anti-interference drive device of the present invention, a control chip and a switching tube connected to the anti-interference drive device are also drawn in the figure. The control chip is configured to issue an initial drive signal, and the switching tube is driven to work by the target drive signal finally output by the anti-interference drive device. As Figure 1 shown, an anti-interference drive device provided by this embodiment and applied to a high-power bridge circuit includes: a comparator, a voltage-to-current circuit, a current-to-voltage circuit, and a drive circuit;

[0033] The output end of the comparator is connected to the input end of the voltage-to-current circuit, and is used to receive the initial drive signal issued by the control chip and reverse-convert it into a reverse drive signal;

[0034] The output end of the voltage-to-current circuit is connected to the input end of the current-to-voltage circuit, and is used to convert the reverse drive signal into a reverse on-off current signal;

[0035] The output end of the current-to-voltage circuit is connected to the input end of the drive chip, and is used to convert the reverse on-off current signal into an intermediate drive signal; the voltage amplitude of the intermediate drive signal is the same as that of the reverse drive signal;

[0036] A drive circuit is used to perform voltage conversion on an intermediate drive signal to obtain a target drive signal for driving a switching transistor.

[0037] Optionally, the current-to-voltage circuit includes: the cathode of an optocoupler serves as the input end of the current-to-voltage circuit, which is used to control the cathode voltage to be less than the anode voltage to turn on the current, and is also used to control the cathode voltage to be greater than or equal to the anode voltage to turn off the current. Among them, the amplitude of the cathode voltage of the optocoupler is greater than the anode voltage to achieve negative voltage turn-off.

[0038] An optocoupler, the cathode of the optocoupler serves as the input end of the current-to-voltage circuit, which is used to control the cathode voltage to be less than the anode voltage to turn on the current, and is also used to control the cathode voltage to be greater than or equal to the anode voltage to turn off the current. Among them, the amplitude of the cathode voltage of the optocoupler is greater than the anode voltage to achieve negative voltage turn-off.

[0039] Furthermore, the on-off of the current in the primary side of the optocoupler forms an on-off current signal, which is converted into an intermediate drive signal by the optocoupler. The intermediate drive signal enters the drive circuit and outputs a target drive signal.

[0040] Furthermore, the voltage amplitude of the initial drive signal is in a first voltage range, the intermediate drive signal is in a second voltage range, and the voltage amplitude of the target drive signal is in a third voltage range.

[0041] In one embodiment, the anti-interference drive device of the present invention applied to a high-power bridge circuit includes a comparator, a voltage-to-current circuit, a current-to-voltage circuit, and a drive circuit.

[0042] The comparator is used to receive an initial drive signal sent by a control chip. In this embodiment, the initial drive signal is a drive signal sent by the control chip in a first voltage range, such as a drive signal of 0 - 3.3V, such as DSP_PWM1A. The comparator reversely converts it into a reverse drive signal. In this embodiment, the comparator U1 is selected. After being reversely converted by U1, a reverse drive signal PWM1Aa in a second voltage range, such as 0 - 12V, is obtained. The output end of the comparator U1 is connected to the input end of the voltage-to-current circuit, and the reverse drive signal PWM1Aa is output to the voltage-to-current circuit.

[0043] The voltage-to-current circuit is used to convert the reverse drive signal into a reverse on-off current signal. The voltage-to-current circuit includes a second drive chip. In this embodiment, the second drive chip U2 is selected. U2 enhances the input reverse drive signal PWM1Aa to form an enhanced drive signal PWM1Ab and converts it into a reverse on-off current signal. The output end of the voltage-to-current circuit is connected to the input end of the current-to-voltage circuit, and the reverse on-off current signal is output to the current-to-voltage circuit.

[0044] If the device further includes a filtering circuit, its input end is the input end of the voltage-to-current circuit, that is, it receives the 0-12V reverse drive signal PWM1Aa output by the comparator. The output end of the filtering circuit is connected to the input end of the second drive chip U2. The filtering circuit is composed of a resistor and a capacitor, for example, a low-pass filter composed of resistor R1 and capacitor C1, which is used to perform noise filtering on the reverse drive signal PWM1Aa to reduce the influence of interference signals on the subsequent circuit.

[0045] The current-to-voltage circuit is used to convert the reverse on-off current signal into an intermediate drive signal, and the voltage amplitude of the intermediate drive signal is the same as that of the reverse drive signal, both being 0-12V. In this embodiment, the current-to-voltage circuit includes an optocoupler U3. The cathode of the optocoupler U3 serves as the input end of the current-to-voltage circuit to receive the reverse on-off current signal. The voltage amplitude of the anode of the optocoupler U3 is, for example, 12V, while the maximum voltage of the enhanced drive signal PWM1Ab is, for example, 15V. In this way, when the PWM1Ab signal is at a low level, the cathode voltage of the optocoupler is lower than the anode, forming a negative voltage to turn off, making the optocoupler U3 more reliable when turned off and not easily affected by external electromagnetic interference. The on-off of the current in the primary side of the optocoupler U3 forms an on-off current signal, which is converted into an intermediate drive signal PWM1Ac of 0-12V by the optocoupler U3. The output end of the current-to-voltage circuit is connected to the input end of the drive circuit, and the intermediate drive signal PWM1Ac is output to the drive circuit.

[0046] The drive circuit is used to perform voltage conversion on the intermediate drive signal to obtain a target drive signal to drive the switching tube. In this embodiment, the drive circuit includes a drive chip U4. After receiving the intermediate drive signal PWM1Ac, U4 converts it into a third voltage range, for example, a target drive signal PWM1 of -8V-12V, which is used to drive the switching tube to work. In a high-power bridge circuit, a stable and reliable target drive signal can ensure the normal conduction and turn-off of the switching tube and guarantee the stable operation of the circuit.

[0047] Through the coordinated operation of the above-mentioned various parts of the circuit, the anti-interference drive device of the present invention utilizes the strong anti-interference ability of the current signal to effectively solve the problem that the drive signal in the high-power bridge circuit is easily affected by electromagnetic interference. The introduction of the negative voltage reliable turn-off function in the voltage-to-current circuit further improves the anti-interference ability and reliability of the signal. At the same time, by adding signal conversion circuits at key positions, the optimization of the existing drive circuit is realized without significantly changing the overall circuit structure, which has strong practicability.

[0048] In one embodiment, as Figure 3 shown, before using the anti-interference drive device of the present invention applied to the high-power bridge circuit, the drive waveform would have the situation of missing pulses. After using it, the drive waveform is normal and there are no missing pulses, which can prove that the anti-interference drive circuit has anti-interference ability.

[0049] In the present invention, a voltage-to-current circuit with a reliable negative-pressure cut-off function is added at the back end of the control chip to convert the voltage signal vulnerable to interference into a current signal with strong anti-interference ability, thereby enhancing the anti-interference ability of the drive circuit. A current-to-voltage circuit is added near the drive chip, and finally the current signal is converted into a voltage signal and transmitted to the switching tube through the drive chip.

[0050] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0051] In addition, the terms such as "first" and "second" used in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in this embodiment. Thus, the features defined with terms such as "first" and "second" in the embodiments of the present invention can explicitly or implicitly indicate that at least one such feature is included in this embodiment. In the description of the present invention, the meaning of the word "plural" is at least two or more than two, such as two, three, four, etc., unless otherwise explicitly and specifically defined in the embodiment.

[0052] In the present invention, unless otherwise explicitly specified or limited in the embodiments, the terms "installation", "connection", "connection", and "fixation" etc. appearing in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or integrated. It can be understood that it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the communication inside two components, or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific implementation situations.

[0053] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as a limitation to the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An anti-interference driving device applied to a high-power bridge circuit, characterized in that: include: Comparator, voltage-to-current circuit, current-to-voltage circuit and driving circuit; The output end of the comparator is connected to the input end of the voltage-to-current circuit, and is used to receive the initial driving signal sent by the control chip and reversely convert it into a reverse driving signal; The output end of the voltage-to-current circuit is connected to the input end of the current-to-voltage circuit, and is used to convert the reverse driving signal into a reverse on-off current signal; The output end of the current-to-voltage circuit is connected to the input end of the driving chip, and is used to convert the reverse on-off current signal into an intermediate driving signal; the intermediate driving signal has the same voltage amplitude as the reverse driving signal; The driving circuit is used to perform voltage conversion on the intermediate driving signal to obtain a target driving signal to drive the switch tube.

2. The anti-interference driving device for high-power bridge circuit according to claim 1, characterized in that: The current-to-voltage circuit comprises: An optocoupler, wherein the cathode of the optocoupler serves as the input end of a current-to-voltage circuit, and is used to control the cathode voltage to be less than the anode voltage to achieve current switching, and is also used to control the cathode voltage to be greater than or equal to the anode voltage to achieve current switching off, wherein the cathode voltage amplitude of the optocoupler is greater than the anode voltage to achieve negative voltage switching off.

3. The anti-interference driving device for high-power bridge circuit according to claim 1, characterized in that: The voltage-to-current circuit comprises: The second driving chip is used to amplify the reverse driving signal and convert it into a reverse switching current signal.

4. The anti-interference driving device for high-power bridge circuit according to claim 2, characterized in that: The current on and off of the primary side of the optocoupler forms a switchable current signal, which is converted into an intermediate drive signal by the optocoupler. The intermediate drive signal enters the drive circuit and outputs a target drive signal.

5. The anti-interference driving device for high-power bridge circuit according to claim 1, characterized in that: The voltage amplitude of the initial driving signal is in a first voltage range, the voltage amplitude of the intermediate driving signal is in a second voltage range, and the voltage amplitude of the target driving signal is in a third voltage range.

6. The anti-interference driving device for high-power bridge circuit according to claim 1, characterized in that: The voltage amplitude of the reverse driving signal is in the second voltage interval.

7. The anti-interference driving device for high-power bridge circuit according to claim 3, characterized in that: The voltage-to-current circuit further includes a filter circuit: The input end of the filter circuit is the input end of the voltage-to-current circuit, the output end of the filter circuit is connected to the input end of the second driver chip, the filter circuit includes a circuit composed of a resistor and a capacitor, and is used to filter out noise on the reverse drive signal in the second voltage interval output by the comparator.

8. An anti-interference driving system applied to a high-power bridge circuit, characterized in that: It comprises an anti-interference driving device applied to a high-power bridge circuit as described in any one of claims 1 to 7.

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