A zero-crossing detection circuit with simple structure

Abstract

The present application aims to provide a zero-crossing detection circuit with simple structure, unlike the conventional Hall effect IC, the zero-crossing detection Hall effect IC can be sensed at the moment of polarity change, which can prevent the efficiency reduction problem caused by the missed output of the Hall effect IC, at the same time, the zero-crossing detection Hall effect IC can be sensed at the moment of polarity change, regardless of whether the distance between the magnet and the sensor changes, it can still output accurately, prevent efficiency reduction due to manufacturing changes, and use the zero-crossing detection Hall effect IC to detect the polarity change, without considering the change of magnetic flux density caused by various external conditions, which means that simpler software can be used to provide smooth rotation control without calibration.

Description

Technical Field

[0001] This invention relates to the field of circuit testing technology, and in particular to a zero-crossing detection circuit with a simple structure. Background Technology

[0002] Zero-crossing detection causes the output signal to flip at the zero-crossing point of the input signal. In brushless motors, the temperature of the Hall effect IC changes significantly with environmental and motor load fluctuations. As the motor load increases, the coil generates heat, raising the temperature of the magnet and causing a change in magnetic flux density. This affects the magnitude of the Hall voltage sensed by the Hall effect IC. In traditional Hall effect ICs, the change in magnetic flux density due to temperature rise affects the timing of output switching, causing the signal to miss the optimal output time, resulting in reduced motor efficiency and large dispersion in operating efficiency. At the same time, to ensure smooth and high-speed operation of the motor, precise rotation angle control is required by software. If the change in magnetic flux density also needs to be considered, the software will need to perform even finer control to check more variables. Therefore, this invention proposes zero-crossing detection for driving brushless motors and solves the above-mentioned problems. Summary of the Invention

[0003] The purpose of this invention is to provide a simple zero-crossing detection circuit. By setting up a comparator, a cross-region detection section, and an output section, it effectively solves the problems of reduced efficiency, large dispersion of operating efficiency, and difficulty in accurately controlling the rotation angle of brushless motors, making it easy to promote.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0005] A simple zero-crossing detection circuit includes a comparator, a cross-region detection section, and an output section. The comparator has three voltage levels: V1, 0, and V2. V1 is a voltage level slightly greater than 0, and V2 is a voltage level slightly less than 0. The comparator is connected to an input signal. The cross-region detection section includes four output signals: A_posedge, B_posedge, A_negedge, and B_negedge.

[0006] The input signal is compared with V1, 0, and V2 respectively. The region where the input signal is greater than V1 is region one, the region where the input signal is greater than 0 and less than V1 is region two, the region where the input signal is greater than V2 and less than 0 is region three, and the region where the input signal is less than V2 is region four.

[0007] When the voltage value of the input signal crosses from region three to region one, the output signal A_posedge will output a positive pulse with a very narrow width;

[0008] When the voltage value of the input signal crosses from region four to region two, the output signal B_posedge will output a very narrow positive pulse;

[0009] When the voltage value of the input signal crosses from region one to region three, the output signal A_negedge will output a very narrow positive pulse.

[0010] When the voltage value of the input signal crosses from region two to region four, the output signal B_negedge will output a very narrow positive pulse.

[0011] The beneficial effects of this invention are as follows:

[0012] This invention discloses a simple zero-crossing detection circuit. Unlike traditional Hall effect ICs, the zero-crossing detection Hall effect IC can sense the instantaneous polarity change. This prevents the efficiency reduction problem that occurs when the Hall effect IC misses the optimal output time. At the same time, the zero-crossing detection Hall effect IC can sense the polarity change and can still output accurately regardless of whether the distance between the magnet and the sensor changes, preventing efficiency reduction due to manufacturing variations. Furthermore, using the zero-crossing detection Hall effect IC to detect polarity changes eliminates the need to consider changes in magnetic flux density caused by various external conditions. This means that simpler software can be used to provide smooth rotation control without calibration. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of a simple zero-crossing detection circuit according to the present invention;

[0014] Figure 2 This is a schematic diagram showing the comparison between the input signal and four regions of a simple zero-crossing detection circuit according to the present invention. Detailed Implementation

[0015] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0016] To make the content of this invention easier to understand, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0017] like Figure 1The zero-crossing detection circuit consists of three parts: a comparator, a cross-region detection section, and an output section. V1 is a level slightly greater than 0, and V2 is a level slightly less than 0. The circuit can filter out interference signals with amplitudes smaller than V1 (or 0-V2).

[0018] Comparator: The input signal is compared with V1, 0, and V2 respectively. These three comparison points divide the voltage into four regions (e.g., ...). Figure 2 Region 1 is the region greater than V1, Region 2 is the region greater than 0 and less than V1, Region 3 is the region greater than V2 and less than 0, and Region 4 is the region less than V2.

[0019] Cross-region detection: When the input signal voltage value is detected to cross from region 3 to region 1, the output signal A_posedge will output a very narrow positive pulse (e.g., Figure 2 (times t1, t5, t9, and t13);

[0020] When the input signal voltage value is detected to cross from region four to region two, the output signal B_posedge will output a very narrow positive pulse (e.g., Figure 2 (times t0, t4, t8, t12, and t16);

[0021] When the input signal voltage value is detected to cross from region one to region three, the output signal A_negedge will output a very narrow positive pulse (e.g., Figure 2 (at times t2, t6, t10, and t14);

[0022] When the input signal voltage value is detected to cross from region two to region four, the output signal B_negedge will output a very narrow positive pulse (e.g., Figure 2 (Times t3, t7, t11, t15, and t17).

[0023] Output: A positive pulse of A_posedge or B_posedge will set OUT to 1, and a positive pulse of A_negedge or B_negedge will set OUT to 0.

[0024] When the input is a sine wave, the output waveform has a 50% duty cycle. Normally, it will flip when the input is 0. Only when there is interference near 0 will the output possibly flip at V1 (or V2). Figure 2 (at time t17), but this will not significantly affect the output duty cycle.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zero-crossing detection circuit with a simple structure, characterized in that, The detection circuit includes a comparator, a cross-region detection section, and an output section. The comparator has three voltage levels: V1, 0, and V2. V1 is a voltage level slightly greater than 0, and V2 is a voltage level slightly less than 0. The comparator is connected to the input signal. The cross-region detection section includes four output signals: A_posedge, B_posedge, A_negedge, and B_negedge. The input signal is compared with V1, 0, and V2 respectively. The region where the input signal is greater than V1 is region one, the region where the input signal is greater than 0 and less than V1 is region two, the region where the input signal is greater than V2 and less than 0 is region three, and the region where the input signal is less than V2 is region four. When the voltage value of the input signal crosses from region three to region one, the output signal A_posedge will output a positive pulse with a very narrow width; When the voltage value of the input signal crosses from region four to region two, the output signal B_posedge will output a very narrow positive pulse; When the voltage value of the input signal crosses from region one to region three, the output signal A_negedge will output a very narrow positive pulse. When the voltage value of the input signal crosses from region two to region four, the output signal B_negedge will output a very narrow positive pulse; A positive pulse of the output signal A_posedge or B_posedge will set the output of the output section to one, and a positive pulse of the output signal A_negedge or B_negedge will set the output of the output section to zero.

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