Power failure rapid detection circuit for high-voltage brushless motor driver

Abstract

The utility model provides a power failure rapid detection circuit for a high-voltage brushless motor driver, and relates to the technical field of electronic circuits. Comprising a voltage division circuit which is connected with an external power supply end of the high-voltage brushless motor driver and performs voltage division on high-voltage alternating-current voltage; the negative half-cycle voltage clamping circuit is connected with the voltage division circuit and clamps the negative half-cycle voltage of the high-voltage alternating-current voltage to a fixed voltage; the current limiting circuit is connected with the negative half-cycle voltage clamping circuit and is used for limiting the current in the circuit; the input end of the optical coupler is connected with the current limiting circuit; and the output signal end is arranged at the output end of the optocoupler. According to the invention, after high-voltage AC voltage power supply is cut off, continuous high level can be output at the output end of the optocoupler, so that whether external power supply is cut off is identified.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a high-voltage brushless motor driver power failure rapid detection circuit. Background Technology

[0002] High-voltage brushless motor drivers are used in applications requiring frequent braking, where an external power supply needs to be cut off to stop the motor in an emergency. During continuous braking, the brushless motor generates its own electricity, causing the bus voltage to remain high, which in turn keeps the driver powered, preventing the motor from stopping.

[0003] Therefore, designing a detection circuit that can detect whether the external power supply has failed is one of the urgent problems to be solved. Utility Model Content

[0004] This application provides a high-voltage brushless motor driver power failure rapid detection circuit to at least solve the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this application, a high-voltage brushless motor driver power-off fast detection circuit is provided, comprising:

[0006] The voltage divider circuit is connected to the external power supply terminal of the high-voltage brushless motor driver to divide the high-voltage AC voltage.

[0007] The negative half-cycle voltage clamping circuit is connected to the voltage divider circuit to clamp the negative half-cycle voltage of the high voltage AC voltage to a fixed voltage.

[0008] A current-limiting circuit is connected to the negative half-cycle voltage clamping circuit to limit the current in the circuit.

[0009] An optocoupler, the input terminal of which is connected to a current limiting circuit;

[0010] The output signal terminal is located at the output terminal of the optocoupler.

[0011] In some embodiments of the first aspect of this application, the external power supply terminal of the high-voltage brushless motor driver includes a live wire and a neutral wire.

[0012] In some embodiments of the first aspect of this application, the voltage divider circuit includes a first resistor and a second resistor connected in series on the live wire.

[0013] In some embodiments of the first aspect of this application, the negative half-cycle voltage clamping circuit includes a first diode, the anode of the first diode being connected to the neutral line, and the cathode of the first diode being connected to the neutral line.

[0014] In some embodiments of the first aspect of this application, the current limiting circuit includes a third resistor, a first end of which is connected to the live wire, and a second end of which is connected to the live wire.

[0015] In some embodiments of the first aspect of this application, the optocoupler is of model PC817C.

[0016] In some embodiments of the first aspect of this application, the output signal terminal is connected to the output signal power supply terminal via a pull-up resistor.

[0017] Compared with the prior art, this application has the following advantages:

[0018] This application divides, clamps, and limits the high-voltage AC voltage at the external power supply terminal of the high-voltage brushless motor driver before inputting it to an optocoupler. When the high-voltage AC voltage is supplied, the output is a square wave signal. When the high-voltage AC voltage is cut off, a continuous high level can be output at the output terminal of the optocoupler, which is the output signal terminal of this detection circuit, thereby identifying whether the external power supply has been cut off.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0020] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0021] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0022] Figure 1 The circuit block diagram of this application is shown.

[0023] Figure 2 The specific circuit diagram of this application is shown. Detailed Implementation

[0024] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] Please refer to Figure 1 and Figure 2 This embodiment provides a high-voltage brushless motor driver power-off rapid detection circuit, including:

[0026] The voltage divider circuit is connected to the external power supply terminal of the high-voltage brushless motor driver to divide the high-voltage AC voltage.

[0027] Specifically, the external power supply terminal of the high-voltage brushless motor driver includes a live wire (L) and a neutral wire (N). The voltage divider circuit includes several voltage divider resistors connected in series on the live wire. In this embodiment, the first resistor R1 and the second resistor R2 divide the high-voltage AC voltage.

[0028] The negative half-cycle voltage clamping circuit is connected to the voltage divider circuit to clamp the negative half-cycle voltage of the high-voltage AC voltage to a fixed voltage.

[0029] Specifically, the negative half-cycle voltage clamping circuit includes a first diode D1, with its anode and cathode connected to the neutral line, specifically serving as the output terminal of the voltage divider circuit. The first diode D1 clamps the high-voltage AC negative half-cycle voltage to approximately 0.7V to protect the optocoupler.

[0030] A current-limiting circuit is connected to the negative half-cycle voltage clamping circuit to limit the current in the circuit.

[0031] Specifically, the current limiting circuit includes a third resistor R3, the first end of which is connected to the live wire, and the second end of which is connected to the live wire, i.e., in parallel with the first diode D1.

[0032] Optocoupler U1, the input terminal of which is connected to the current limiting circuit.

[0033] The preferred model of the optocoupler U1 is PC817C. The optocoupler U1 is used to isolate input and output signals. At the same time, as a key component of the signal detection circuit, the positive half-cycle voltage output by the current limiting circuit turns U1 on, and vice versa, U1 is turned off during the negative half-cycle.

[0034] The output signal terminal AC_TEST is located at the output terminal of the optocoupler U1. The output signal terminal AC_TEST is connected to the output signal power supply terminal VDD via a pull-up resistor R4. The pull-up resistor R4 provides a high-level voltage to the output signal terminal AC_TEST, thereby limiting current when the optocoupler U1 is on.

[0035] The output signal terminal AC_TEST is the output terminal of this detection circuit. When the optocoupler U1 is turned on, the output signal terminal AC_TEST outputs a low level. When the optocoupler U1 is turned off, the output signal terminal AC_TEST outputs a high level voltage. Under the condition of high voltage AC voltage power supply, the output is a square wave signal. After the high voltage AC voltage power supply is cut off, the output is continuously high level. The back-end circuit can know that the external power supply is cut off by detecting the duration of the high level of the AC_TEST output signal.

[0036] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-voltage brushless motor driver power-off rapid detection circuit, characterized in that, include: The voltage divider circuit is connected to the external power supply terminal of the high-voltage brushless motor driver to divide the high-voltage AC voltage. The negative half-cycle voltage clamping circuit is connected to the voltage divider circuit to clamp the negative half-cycle voltage of the high voltage AC voltage to a fixed voltage. A current-limiting circuit is connected to the negative half-cycle voltage clamping circuit to limit the current in the circuit. An optocoupler, the input terminal of which is connected to a current limiting circuit; The output signal terminal is located at the output terminal of the optocoupler.

2. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 1, characterized in that, The external power supply terminals of the high-voltage brushless motor driver include a live wire and a neutral wire.

3. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 2, characterized in that, The voltage divider circuit includes a first resistor and a second resistor connected in series on the live wire.

4. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 2, characterized in that, The negative half-cycle voltage clamping circuit includes a first diode, the positive terminal of which is connected to the neutral line, and the negative terminal of which is also connected to the neutral line.

5. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 2, characterized in that, The current limiting circuit includes a third resistor, the first end of which is connected to the live wire, and the second end of which is connected to the live wire.

6. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 1, characterized in that, The optocoupler used is model PC817C.

7. The high-voltage brushless motor driver power-off rapid detection circuit according to claim 1, characterized in that, The output signal terminal is connected to the output signal power supply terminal via a pull-up resistor.

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