Power supply ripple detection circuit and device

Abstract

The utility model discloses a power supply ripple detection circuit and device, and relates to the technical field of voltage detection, the power supply ripple detection circuit comprises a filtering unit, an amplification unit and a comparison unit, the filtering unit is connected with a switching power supply and is used for filtering a signal higher than the switching frequency of the switching power supply, and the amplification unit is connected with the comparison unit. The amplification unit is connected with the filtering unit and used for amplifying a voltage signal output by the filtering unit, and the comparison unit is connected with the amplification unit and used for comparing the voltage signal with a reference voltage and outputting an alarm signal when a ripple wave of the voltage signal exceeds or is equal to a ripple wave of the reference voltage. The ripple fluctuation condition of the voltage signal can be obtained in time through the comparison unit, an alarm signal is automatically sent out when the ripple of the voltage signal exceeds or is equal to the reference voltage, the voltage ripple does not need to be detected through an oscilloscope, the numerical value does not need to be manually read, the detection process of the voltage ripple is simplified, and the detection precision and efficiency are improved.

Description

Technical Field

[0001] This utility model relates to the field of voltage detection technology, and in particular to a power supply ripple detection circuit and device. Background Technology

[0002] Ripple in a switching power supply refers to the AC component superimposed on the DC stability in the DC voltage or current. This AC component causes periodic fluctuations in the power supply output, similar to ripples on water, hence the name ripple. Excessive ripple voltage can interfere with the circuit and may damage the load.

[0003] In the existing technology, the ripple of the power supply voltage is detected by using an oscilloscope. However, the detection by using an oscilloscope requires manual reading of the values ​​and determination of whether they exceed the threshold. The detection process is cumbersome and it is difficult to grasp the fluctuation of the voltage ripple in a timely manner. Utility Model Content

[0004] This utility model provides a power supply ripple detection circuit and device to solve the technical problem in the prior art that the voltage ripple detection using an oscilloscope requires manual reading of values ​​and determination of whether it exceeds the threshold, which is cumbersome and makes it difficult to grasp the fluctuation of voltage ripple in a timely manner.

[0005] In a first aspect, a power supply ripple detection circuit is provided, comprising:

[0006] A filtering unit, which is connected to a switching power supply, is used to filter out signals that are higher than the switching frequency of the switching power supply.

[0007] An amplification unit, connected to the filtering unit, is used to amplify the voltage signal output by the filtering unit;

[0008] A comparison unit, connected to the amplification unit, is used to compare the voltage signal with a reference voltage and output an alarm signal when the ripple of the voltage signal exceeds or equals the ripple of the reference voltage.

[0009] In some embodiments, the filtering unit includes:

[0010] A first inductor L1, a second capacitor C2, a third capacitor C3 are connected. The first end of the first inductor L1 is connected to the switching power supply. The second end of the first inductor L1 is connected to the first end of the second capacitor C2. The second end of the second capacitor C2 is grounded. The first end of the second inductor L2 is connected to the second end of the first inductor L1 and the first end of the second capacitor C2. The second end of the second inductor L2 is connected to the first end of the third capacitor C3. The second end of the third capacitor C3 is grounded.

[0011] In some embodiments, the amplification unit includes:

[0012] The amplifier IC1, the first resistor R1, and the second resistor R2 are connected. The first input terminal of the amplifier IC1 is connected to the second terminal of the second inductor L2. The second input terminal of the amplifier IC1 is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is grounded. The second input terminal of the amplifier IC1 is also connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the output terminal of the amplifier IC1.

[0013] In some embodiments, the amplification unit further includes:

[0014] The fourth capacitor C4 has its first end connected to the power supply terminal of the amplifier IC1, and its second end connected to the ground terminal of the amplifier IC1.

[0015] The fifth capacitor C5 has its first terminal connected to the output terminal of the amplifier IC1, and its second terminal grounded.

[0016] In some embodiments, the comparison unit includes:

[0017] A first comparator IC2 has its first input terminal connected to the output terminal of the amplifier IC1, and its second input terminal connected to a reference voltage source, for comparing the maximum ripple value of the voltage signal with the maximum value of the reference voltage.

[0018] The second comparator IC3 has its first input terminal connected to the reference voltage source and its second input terminal connected to the output terminal of the amplifier IC1. It is used to compare the minimum ripple value of the voltage signal with the minimum value of the reference voltage.

[0019] Dual diodes D1 are connected to the output terminals of the first comparator IC2 and the second comparator IC3, and are used to conduct when the maximum or minimum ripple value of the voltage signal exceeds or equals the reference voltage.

[0020] In some embodiments, the comparison unit further includes:

[0021] The sixth capacitor C6 has its first terminal connected to the power supply terminal of the first comparator IC2, and its second terminal connected to the ground terminal of the first comparator IC2.

[0022] The seventh capacitor C7 has its first end connected to the power supply terminal of the second comparator IC3, and its second end connected to the ground terminal of the second comparator IC3.

[0023] In some embodiments, the comparison unit further includes:

[0024] The third resistor R3 has its first end connected to the negative terminal of the dual diode D1, and its second end grounded.

[0025] In some embodiments, the comparison unit further includes:

[0026] The second diode D2 has its cathode connected to the cathode of the dual diode D1, and its anode grounded.

[0027] In some embodiments, the power supply ripple detection circuit further includes:

[0028] A first capacitor C1 is connected at its first end to the switching power supply, and at its second end to the first end of the first inductor L1.

[0029] Secondly, a power ripple detection device is provided, including the aforementioned power ripple detection circuit.

[0030] The beneficial effects of the technical solution provided by this utility model include:

[0031] This utility model provides a power supply ripple detection circuit and device. The power supply ripple detection circuit includes a filtering unit, an amplification unit, and a comparison unit. The filtering unit is connected to a switching power supply and is used to filter out signals higher than the switching frequency of the switching power supply. The amplification unit is connected to the filtering unit and is used to amplify the voltage signal output by the filtering unit. The comparison unit is connected to the amplification unit and is used to compare the voltage signal with a reference voltage. When the ripple of the voltage signal exceeds or equals the ripple of the reference voltage, an alarm signal is output. The comparison unit can promptly obtain the ripple fluctuation of the voltage signal and automatically issue an alarm signal when the ripple of the voltage signal exceeds or equals the reference voltage. This eliminates the need to use an oscilloscope to detect voltage ripple and manually read values, simplifying the voltage ripple detection process and improving detection accuracy and efficiency. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A block diagram of a power supply ripple detection circuit provided for an embodiment of this utility model;

[0034] Figure 2 A schematic diagram of a power supply ripple detection circuit provided for an embodiment of this utility model;

[0035] Figure 3 A schematic diagram of the filtering unit provided in an embodiment of this utility model;

[0036] Figure 4 A schematic diagram of the amplification unit provided in an embodiment of this utility model;

[0037] Figure 5 A schematic diagram of the comparison unit provided in an embodiment of this utility model. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] This utility model provides a power supply ripple detection circuit and device, which can solve the technical problem in the prior art that the voltage ripple detection using an oscilloscope requires manual reading of values ​​and determination of whether it exceeds the threshold, the detection process is cumbersome, and it is difficult to grasp the fluctuation of voltage ripple in a timely manner.

[0040] Figure 1 This utility model provides a power supply ripple detection circuit, which includes a filtering unit, an amplification unit, and a comparison unit.

[0041] The filtering unit is connected to the switching power supply and is used to filter out signals higher than the switching frequency of the switching power supply. The amplification unit is connected to the filtering unit and is used to amplify the voltage signal output by the filtering unit. The comparison unit is connected to the amplification unit and is used to compare the voltage signal with a reference voltage, and output an alarm signal when the ripple of the voltage signal exceeds or equals the ripple of the reference voltage.

[0042] The power ripple detection circuit of this utility model embodiment includes a filtering unit, an amplification unit, and a comparison unit. The filtering unit is connected to the switching power supply and is used to filter out signals higher than the switching frequency of the switching power supply. The amplification unit is connected to the filtering unit and is used to amplify the voltage signal output by the filtering unit. The comparison unit is connected to the amplification unit and is used to compare the voltage signal with a reference voltage. When the ripple of the voltage signal exceeds or equals the ripple of the reference voltage, the comparison unit automatically outputs an alarm signal. The comparison unit can promptly obtain the ripple fluctuation of the voltage signal and can promptly report when the ripple of the voltage signal exceeds or equals the reference voltage, facilitating timely processing. It eliminates the need to use an oscilloscope to detect voltage ripple and manually read values, simplifying the voltage ripple detection process and improving detection accuracy and efficiency.

[0043] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 3 As shown, the filtering unit includes: a first inductor L1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C3. The first terminal of the first inductor L1 is connected to the switching power supply. The second terminal of the first inductor L1 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is grounded. The first terminal of the second inductor L2 is connected to the second terminals of the first inductor L1 and the second capacitor C2. The second terminal of the second inductor L2 is connected to the first terminal of the third capacitor C3, and the second terminal of the third capacitor C3 is grounded. The first inductor L1, the second capacitor C2, the second inductor L2, and the third capacitor C3... The three capacitors C3 form a second-order low-pass filter, which is a passive low-pass filter. Capacitors have low impedance at high frequencies, guiding high-frequency noise to ground, thus achieving a filtering effect. Inductors, on the other hand, have high impedance to high-frequency signals, hindering their passage. This frequency-selective design allows low-frequency signals to pass while suppressing or eliminating high-frequency interference signals, thereby filtering out signals close to or higher than the switching frequency of the power supply. The second-order low-pass filter can more effectively suppress high-frequency noise, thereby improving signal clarity and stability. The bandwidth of the filtering unit is set according to the switching frequency of the power supply and the bandwidth requirements of the output voltage ripple.

[0044] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 4 As shown, the amplification unit includes: amplifier IC1, first resistor R1, and second resistor R2. The first input terminal of amplifier IC1 is connected to the second terminal of the second inductor L2, and the second input terminal of amplifier IC1 is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is grounded, and the second input terminal of amplifier IC1 is also connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the output terminal of amplifier IC1. The voltage signal output by the switching power supply is filtered by the filtering unit and then output to the first input terminal of amplifier IC1. Amplifier IC1, first resistor R1, and second resistor R2 form a negative feedback amplification circuit to amplify the filtered voltage ripple signal. Since the voltage ripple signal is small, the detection error can be reduced and the detection accuracy improved by amplification.

[0045] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 4 As shown, the amplification unit further includes a fourth capacitor C4 and a fifth capacitor C5. The first end of the fourth capacitor C4 is connected to the power supply terminal of the amplifier IC1, and the second end of the fourth capacitor C4 is connected to the ground terminal of the amplifier IC1. The first end of the fifth capacitor C5 is connected to the output terminal of the amplifier IC1, and the second end of the fifth capacitor C5 is grounded. The fourth capacitor C4 and the fifth capacitor C5 are filter capacitors used to filter out noise and AC components in the voltage, so as to keep the output voltage stable. At the same time, the filter capacitors can also short-circuit high-frequency noise signals to ground, further reducing noise interference.

[0046] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 5As shown, the comparison unit includes: a first comparator IC2, a second comparator IC3, and a dual diode D1. The first input terminal of the first comparator IC2 is connected to the output terminal of the amplifier IC1, and the second input terminal of the first comparator IC2 is connected to a reference voltage source for comparing the maximum ripple value of the voltage signal with the maximum value of the reference voltage. The first input terminal of the second comparator IC3 is connected to the reference voltage source, and the second input terminal of the second comparator IC3 is connected to the output terminal of the amplifier IC1 for comparing the minimum ripple value of the voltage signal with the minimum value of the reference voltage. The dual diode D1 is connected to the output terminals of the first comparator IC2 and the second comparator IC3 for conducting when the maximum or minimum ripple value of the voltage signal exceeds or equals the reference voltage.

[0047] Specifically, the voltage ripple signal amplified by the amplification unit is simultaneously output to the first input terminal IN+ of the first comparator IC2 and the second input terminal IN- of the second comparator IC3. The second input terminal IN- of the first comparator IC2 and the first input terminal IN+ of the second comparator IC3 are both connected to the reference voltage source. The reference voltage source provides the ripple requirement threshold of the reference voltage for the second input terminal IN- of the first comparator IC2 and the first input terminal IN+ of the second comparator IC3. The dual diode D1 consists of two diodes connected in parallel. When the voltage Vi of the first input terminal IN+ of the first comparator IC2 is greater than or equal to the voltage ALM_H of its second input terminal IN-, the voltage VO_H of the first comparator IC2 is +Vom, that is, the output voltage VO_H of the first comparator IC2 is the maximum output voltage. The voltage VO_L of the second comparator IC3 is -Vom. Then, the first diode in the dual diode D1 is turned on and the second diode is turned off. The negative terminal of the dual diode D1 is the output terminal and outputs the alarm voltage signal Vout = Vom. When the voltage Vi at the second input terminal IN- of the second comparator IC3 is less than or equal to the voltage ALM_L at its first input terminal IN+, the voltage VO_L at the output terminal of the second comparator IC3 is +Vom, meaning the output voltage VO_L of the second comparator IC3 is the maximum output voltage. The voltage VO_H at the output terminal of the first comparator IC2 is -Vom. In this case, the first diode in the dual diode D1 is cut off, and the second diode is turned on. The cathode of the dual diode D1 is the output terminal, and an alarm voltage signal Vout = Vom is output. When the voltage Vi at the first input terminal IN+ of the first comparator IC2 and the voltage Vi at the second input terminal IN- of the second comparator IC3 are within the ripple requirement threshold of the reference voltage, i.e., ALM_L < Vi < ALM_H, the voltage VO_H at the output terminal of the first comparator IC2 is -Vom, and the voltage VO_L at the output terminal of the second comparator IC3 is -Vom. Both diodes in the dual diode D1 are cut off, so the cathode of the dual diode D1 is the output terminal and there is no output voltage. Therefore, the comparison unit does not output an alarm signal.

[0048] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 5As shown, the comparison unit further includes a sixth capacitor C6 and a seventh capacitor C7. The first end of the sixth capacitor C6 is connected to the power supply terminal of the first comparator IC2, and the second end of the sixth capacitor C6 is connected to the ground terminal of the first comparator IC2. The first end of the seventh capacitor C7 is connected to the power supply terminal of the second comparator IC3, and the second end of the seventh capacitor C7 is connected to the ground terminal of the second comparator IC3. Both the sixth capacitor C6 and the seventh capacitor C7 are filter capacitors used to filter out noise and AC components in the voltage, so as to keep the output voltage stable.

[0049] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 5 As shown, the comparison unit further includes a third resistor R3. The first end of the third resistor R3 is connected to the negative terminal of the dual diode D1, and the second end of the third resistor R3 is grounded. The third resistor R3 is a current-limiting resistor, which can limit the magnitude of the current and prevent the drive current from being too large and damaging the first comparator IC2 and the second comparator IC3, thereby protecting the electrical components in the circuit from damage.

[0050] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 and Figure 5 As shown, the comparison unit further includes a second diode D2, the negative terminal of the second diode D2 is connected to the negative terminal of the dual diode D1, the positive terminal of the second diode D2 is grounded, and the second diode D2 is a Zener diode used to mitigate the impact of signal sudden changes and flips on the subsequent monitoring circuit.

[0051] As an optional implementation, in one embodiment of the utility model, see [link to utility model description]. Figure 2 As shown, the power supply ripple detection circuit further includes: a first capacitor C1, the first end of the first capacitor C1 is connected to the switching power supply, the second end of the first capacitor C1 is connected to the first end of the first inductor L1, and the voltage Vin output by the switching power supply is AC coupled to the filter unit through the first capacitor C1. The appropriate first capacitor C1 needs to be selected according to the self-resonant frequency, cutoff frequency and operating frequency of the circuit.

[0052] This utility model embodiment also provides a power supply ripple detection device, including the aforementioned power supply ripple detection circuit. The power supply ripple detection circuit includes: a filtering unit, an amplification unit, and a comparison unit. The filtering unit is connected to a switching power supply and is used to filter out signals higher than the switching frequency of the switching power supply. The amplification unit is connected to the filtering unit and is used to amplify the voltage signal output by the filtering unit. The comparison unit is connected to the amplification unit and is used to compare the voltage signal with a reference voltage, and output an alarm signal when the ripple of the voltage signal exceeds or equals the ripple of the reference voltage.

[0053] The power ripple detection device of this utility model embodiment includes a power ripple detection circuit comprising a filtering unit, an amplification unit, and a comparison unit. The filtering unit is connected to a switching power supply and is used to filter out signals higher than the switching frequency of the switching power supply. The amplification unit is connected to the filtering unit and is used to amplify the voltage signal output by the filtering unit. The comparison unit is connected to the amplification unit and is used to compare the voltage signal with a reference voltage. When the ripple of the voltage signal exceeds or equals the ripple of the reference voltage, the comparison unit automatically outputs an alarm signal. The comparison unit can promptly obtain the ripple fluctuation of the voltage signal and can promptly report when the ripple of the voltage signal exceeds or equals the reference voltage, facilitating timely processing. It eliminates the need to use an oscilloscope to detect voltage ripple and manually read values, simplifying the voltage ripple detection process and improving detection accuracy and efficiency.

[0054] In the description of this utility model, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0055] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A power supply ripple detection circuit, characterized by, The application relates to a voltage ripple alarm device for a switching power supply, which comprises the following parts: a filter unit connected with the switching power supply, used for filtering signals higher than the switching frequency of the switching power supply; an amplification unit connected with the filter unit, used for amplifying the voltage signal output by the filter unit; a comparison unit connected with the amplification unit, used for comparing the voltage signal with a reference voltage and outputting an alarm signal when the ripple of the voltage signal exceeds or equals the ripple of the reference voltage.

2. The power supply ripple detection circuit of claim 1, wherein, The filter unit comprises: a first inductor L1, a second capacitor C2, a second inductor L2 and a third capacitor C3, the first end of the first inductor L1 is connected with the switching power supply, the second end of the first inductor L1 is connected with the first end of the second capacitor C2, the second end of the second capacitor C2 is grounded, the first end of the second inductor L2 is connected with the second end of the first inductor L1 and the first end of the second capacitor C2, the second end of the second inductor L2 is connected with the first end of the third capacitor C3, and the second end of the third capacitor C3 is grounded.

3. The power supply ripple detection circuit of claim 2, wherein, The amplification unit comprises: an amplifier IC1, a first resistor R1 and a second resistor R2, the first input end of the amplifier IC1 is connected with the second end of the second inductor L2, the second input end of the amplifier IC1 is connected with the first end of the first resistor R1, the second end of the first resistor R1 is grounded, the second input end of the amplifier IC1 is also connected with the first end of the second resistor R2, and the second end of the second resistor R2 is connected with the output end of the amplifier IC1.

4. The power supply ripple detection circuit of claim 3, wherein, The amplification unit further comprises: a fourth capacitor C4, the first end of the fourth capacitor C4 is connected with the power supply end of the amplifier IC1, and the second end of the fourth capacitor C4 is connected with the grounding end of the amplifier IC1; a fifth capacitor C5, the first end of the fifth capacitor C5 is connected with the output end of the amplifier IC1, and the second end of the fifth capacitor C5 is grounded.

5. The power supply ripple detection circuit of claim 4, wherein, The comparison unit comprises: a first comparator IC2, the first input end of the first comparator IC2 is connected with the output end of the amplifier IC1, and the second input end of the first comparator IC2 is connected with a reference voltage source, used for comparing the maximum ripple value of the voltage signal with the maximum value of the reference voltage; a second comparator IC3, the first input end of the second comparator IC3 is connected with the reference voltage source, and the second input end of the second comparator IC3 is connected with the output end of the amplifier IC1, used for comparing the minimum ripple value of the voltage signal with the minimum value of the reference voltage; a double diode D1, connected with the output end of the first comparator IC2 and the output end of the second comparator IC3, used for being turned on when the maximum ripple value or the minimum ripple value of the voltage signal exceeds or equals the reference voltage.

6. The power supply ripple detection circuit of claim 5, wherein, The comparison unit further comprises: a sixth capacitor C6, the first end of the sixth capacitor C6 is connected with the power supply end of the first comparator IC2, and the second end of the sixth capacitor C6 is connected with the grounding end of the first comparator IC2. A seventh capacitor C7, a first end of the seventh capacitor C7 is connected with a power supply end of the second comparator IC3, a second end of the seventh capacitor C7 is connected with a ground end of the second comparator IC3.

7. The power supply ripple detection circuit of claim 6, wherein, The comparison unit further comprises: A third resistor R3, a first end of the third resistor R3 is connected with a negative electrode of the double diode D1, a second end of the third resistor R3 is grounded.

8. The power supply ripple detection circuit of claim 7, wherein, The comparison unit further comprises: A second diode D2, a negative electrode of the second diode D2 is connected with a negative electrode of the double diode D1, a positive electrode of the second diode D2 is grounded.

9. The power supply ripple detection circuit of claim 2, wherein, Further comprising: A first capacitor C1, a first end of the first capacitor C1 is connected with the switching power supply, a second end of the first capacitor C1 is connected with a first end of the first inductor L1.

10. A power supply ripple detection apparatus, characterized by, The power supply ripple detection circuit of any one of claims 1-9.

Images