Ripple detection circuit with self-diagnosis function

Abstract

The invention discloses a ripple detection circuit with a self-diagnosis function, and belongs to the technical field of detection circuits. Comprising a ripple detection unit, a sampling unit, a reference signal generation unit, a processing unit, a first switch and a second switch, the reference signal generation unit and the sampling unit are respectively connected in parallel with the input end of the ripple detection unit through the first switch and the second switch, and the output end of the ripple detection unit is connected with the processing unit; the processing unit outputs a switch control signal to the switch unit and is used for generating a ripple value. Real-time monitoring of ripples is achieved through two-time detection circuit design, a self-diagnosis function is achieved, whether the working state of each device in the circuit is normal or not is detected before normal operation, and a ripple value is obtained through conversion by detecting a converted direct current effective value. The circuit is simple to realize and ensures reliability.

Description

Technical Field

[0001] The invention relates to the technical field of detection circuits, and in particular to a ripple detection circuit with self-diagnosis. Background Art

[0002] Ripple is a phenomenon caused by voltage fluctuations in DC regulated power supplies. Because DC regulated power supplies are generally formed by AC power supplies through rectification and voltage stabilization, it is inevitable that there are some AC components in the DC regulated quantity. This AC component superimposed on the DC regulated quantity is called ripple.

[0003] The ripple at the power output port can affect the operation of electronic equipment and cause instability. In some places with high reliability requirements, the power ripple is detected as a basis for judging the output quality and as feedback for the power output so that strategy switching can be performed in extreme situations. Therefore, the reliability requirements for ripple detection are high. In the current ripple detection process, there is no judgment on the reliability of the detection circuit. Summary of the invention

[0004] In view of the defects of the prior art, the present invention realizes real-time monitoring of ripple through two detection circuit designs, and has a self-diagnosis function. Before normal operation, it detects whether the working status of each device in the circuit is normal, and obtains the ripple value by detecting the converted DC effective value.

[0005] In order to achieve the above object, the present invention provides a ripple detection circuit with self-diagnosis, comprising: a ripple detection unit, a sampling unit, a reference signal generation unit, a processing unit, and a first switch and a second switch;

[0006] The reference signal generating unit and the sampling unit are connected in parallel to the input end of the ripple detecting unit through the first switch and the second switch respectively. The output end of the ripple detecting unit is connected to the processing unit. The processing unit outputs a switch control signal to the switch unit and is used to generate a ripple value at the same time.

[0007] Furthermore, the ripple detection unit is a ripple voltage detection unit or a ripple current detection unit.

[0008] Further, the ripple voltage detection unit includes a bandpass filter, a full-wave rectifier and an RC filter connected in sequence;

[0009] When the ripple detection unit is a ripple voltage detection unit, the sampling module collects and outputs the voltage to be tested.

[0010] Further, the ripple current detection circuit includes a bandpass filter, an amplifier, a full-wave rectifier and an RC filter connected in sequence;

[0011] When the ripple detection unit is a ripple current detection unit, the sampling module collects voltages at both ends of the shunt resistor respectively, and amplifies the voltage difference and then outputs it.

[0012] Furthermore, the processing unit first closes the first switch and opens the second switch through a switch control signal during the first ripple detection and when the ripple detection is awakened again, so as to detect whether the ripple detection unit is working normally. If normal, the processing unit disconnects the first switch and closes the second switch through the switch control signal to perform ripple detection.

[0013] Furthermore, the processing unit is an MCU.

[0014] The present invention also provides a ripple detection method, based on the ripple detection circuit with self-diagnosis as described above, comprising the following steps:

[0015] (1) During the first ripple detection and when the ripple detection is awakened again, the processing unit sends a switch control signal to close the first switch and open the second switch, and the reference signal generation unit generates a ripple signal of a predetermined frequency and inputs it into the ripple detection unit;

[0016] (2) The output of the ripple detection unit is sent to the processing unit, which compares the actual output detection value with the expected output value. If the ripple detection unit is within a predetermined range, it can be determined that the ripple detection unit is working properly, thus completing the circuit diagnosis;

[0017] (3) If the detection is normal, the processing unit sends a switch control signal to open the first switch and close the second switch to perform ripple detection;

[0018] (4) The output of the ripple detection unit is sent to the processing unit, and the processing unit converts the processed ripple current or ripple voltage signal into a ripple value.

[0019] Beneficial effects of the present invention:

[0020] The present invention realizes real-time monitoring of ripples through two detection circuit designs, and has a self-diagnosis function. The first detection is a self-diagnosis detection, which confirms whether the working state of each device in the detection circuit is normal. After confirming that the circuit is normal, a secondary ripple detection is performed. The circuit is simple and reliable to implement, and provides ripple voltage and current for the power supply protection strategy of high-precision sensitive equipment, ensuring safer and more reliable operation of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the structure of a ripple detection circuit with self-diagnosis according to an embodiment of the present invention.

[0022] Figure 2 The figure is a schematic diagram of a ripple voltage detection circuit with self-diagnosis according to an embodiment of the present invention.

[0023] Figure 3The figure is a schematic diagram of a ripple current detection circuit with self-diagnosis according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, the present invention is an embodiment that provides a ripple detection circuit with self-diagnosis, including: a ripple detection unit, a sampling unit, a reference signal generating unit, a processing unit, and a first switch and a second switch.

[0026] The reference signal generating unit and the sampling unit are connected in parallel to the input end of the ripple detecting unit through the first switch and the second switch respectively, and the output end of the ripple detecting unit is connected to the processing unit; the processing unit outputs the switch control signal to the switch unit and generates the ripple value at the same time.

[0027] Among them, the reference signal generating unit generates a ripple signal of a predefined frequency for circuit self-diagnosis; the sampling unit is used to collect the voltage / current signal to be tested; the ripple detection unit is used to preprocess the voltage / current signal to be tested to reduce the test error; the first switch and the second switch are used for switching between the diagnostic circuit and the test circuit; the processing unit is used for switch control and converting the preprocessed voltage / current signal into a ripple value.

[0028] The ripple detection unit is a ripple voltage detection unit or a ripple current detection unit.

[0029] like Figure 2 As shown, the ripple voltage detection unit includes a bandpass filter, a full-wave rectifier and an RC filter connected in sequence. When the ripple detection unit is a ripple voltage detection unit, the sampling module collects the voltage to be tested and outputs it. The output voltage signal contains different frequency signals, which must pass through a bandpass filter to exclude DC signals, low-frequency signals below 15Hz, and high-frequency signals above 33Khz, and then perform full-wave rectification and second-order RC filtering before inputting the smoothed DC signal into the processing unit.

[0030] like Figure 3 As shown, the ripple current detection circuit includes a bandpass filter, an amplifier, a full-wave rectifier and an RC filter connected in sequence; when the ripple detection unit is a ripple current detection unit, the sampling module collects the voltages at both ends of the shunt resistor respectively, and amplifies the voltage difference before outputting it. The output current signal contains a lot of current frequencies, and must pass through a bandpass filter to remove DC signals, low-frequency signals below 15Hz, and high-frequency signals above 33Khz, and then perform current amplification, full-wave rectification, and second-order RC filtering before inputting the smoothed ripple current signal into the processing unit.

[0031] When the processing unit detects the ripple for the first time and wakes up again after the ripple detection, the first switch is closed and the second switch is opened through the switch control signal to detect whether the ripple detection unit is working normally and complete the circuit self-diagnosis. If it is normal, the first switch is opened and the second switch is closed through the switch control signal to perform ripple detection. In the embodiment of the present invention, the processing unit is implemented by MCU. When performing self-diagnosis, the MCU controls the reference signal generation unit to generate a ripple signal of a predefined frequency, which is sent to the ripple detection unit for ripple detection. The MCU compares the actual detection value output by the ripple detection unit with the expected output value. If it is within the predetermined range, it can be determined that the ripple detection unit is working normally. If it exceeds the predetermined range, the circuit is abnormal, and the circuit diagnosis is completed. When the circuit diagnosis result is normal, the actual ripple detection can be performed. The MCU receives the ripple current or ripple voltage signal output by the ripple detection unit, and multiplies it by a predefined parameter (according to the specific circuit setting) to convert the ripple value.

[0032] The present invention also provides a ripple detection method, based on the above-mentioned ripple detection circuit with self-diagnosis, comprising the following steps:

[0033] S101, when the ripple detection is performed for the first time and the ripple detection is awakened again, the processing unit sends a switch control signal to close the first switch and open the second switch, and the reference signal generating unit generates a ripple signal of a predetermined frequency and inputs it into the ripple detection unit;

[0034] S102, the output of the ripple detection unit is sent to the processing unit, and the processing unit compares the actual output detection value with the expected output value. If the ripple detection unit is within a predetermined range, it can be determined that the ripple detection unit is working normally, and the circuit diagnosis is completed;

[0035] S103, if the detection is normal, the processing unit sends a switch control signal to disconnect the first switch and close the second switch to perform ripple detection;

[0036] S104 , the output of the ripple detection unit is sent to the processing unit, and the processing unit converts the processed ripple current or ripple voltage signal into a ripple value.

[0037] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ripple detection circuit with self-diagnosis, characterized in that: include: A ripple detection unit, a sampling unit, a reference signal generation unit, a processing unit, and a first switch and a second switch; The reference signal generating unit and the sampling unit are connected in parallel to the input end of the ripple detecting unit through the first switch and the second switch respectively. The output end of the ripple detecting unit is connected to the processing unit. The processing unit outputs a switch control signal to the switch unit and is used to generate a ripple value at the same time.

2. The ripple detection circuit with self-diagnosis according to claim 1, characterized in that: The ripple detection unit is a ripple voltage detection unit or a ripple current detection unit.

3. The ripple detection circuit with self-diagnosis according to claim 2, characterized in that: The ripple voltage detection unit includes a bandpass filter, a full-wave rectifier and an RC filter connected in sequence; When the ripple detection unit is a ripple voltage detection unit, the sampling module collects and outputs the voltage to be tested.

4. The ripple detection circuit with self-diagnosis according to claim 2, characterized in that: The ripple current detection circuit comprises a bandpass filter, an amplifier, a full-wave rectifier and an RC filter connected in sequence; When the ripple detection unit is a ripple current detection unit, the sampling module collects voltages at both ends of the shunt resistor respectively, and amplifies the voltage difference and then outputs it.

5. The ripple detection circuit with self-diagnosis according to claim 1, characterized in that: The processing unit first closes the first switch and opens the second switch through a switch control signal during the first ripple detection and when the ripple detection is awakened again, so as to detect whether the ripple detection unit works normally. If normal, the processing unit disconnects the first switch and closes the second switch through a switch control signal to perform ripple detection.

6. The ripple detection circuit with self-diagnosis according to claim 1, characterized in that: The processing unit is MCU.

7. A ripple detection method, based on the ripple detection circuit with self-diagnosis according to any one of claims 1 to 6, characterized in that: The steps include: (1) During the first ripple detection and when the ripple detection is awakened again, the processing unit sends a switch control signal to close the first switch and open the second switch, and the reference signal generation unit generates a ripple signal of a predetermined frequency and inputs it into the ripple detection unit; (2) The output of the ripple detection unit is sent to the processing unit, which compares the actual output detection value with the expected output value. If the ripple detection unit is within a predetermined range, it can be determined that the ripple detection unit is working properly, thus completing the circuit diagnosis; (3) If the detection is normal, the processing unit sends a switch control signal to open the first switch and close the second switch to perform ripple detection; (4) The output of the ripple detection unit is sent to the processing unit, and the processing unit converts the processed ripple current or ripple voltage signal into a ripple value.

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