CN217060453U - Monitoring circuit for power supply ripple and noise - Google Patents
Monitoring circuit for power supply ripple and noise Download PDFInfo
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- CN217060453U CN217060453U CN202220528055.XU CN202220528055U CN217060453U CN 217060453 U CN217060453 U CN 217060453U CN 202220528055 U CN202220528055 U CN 202220528055U CN 217060453 U CN217060453 U CN 217060453U
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Abstract
The utility model relates to a monitoring circuit of power supply ripple and noise, which belongs to the technical field of power supply ripple monitoring and comprises a decoupling circuit, a first-stage filter, a second-stage filter, a high-speed operational amplifying circuit, a voltage limiting circuit and a high-speed ADC sampling circuit which are connected in sequence; the output end of the decoupling circuit is also connected with the input end of the switch circuit, and the output end of the switch circuit is connected with the output end of the first-stage filter. The utility model can monitor the ripple and noise condition of the important power supply in the background and judge the health degree of the power supply; meanwhile, the problem that the sampling ADC is burnt by high voltage caused by power-on and power-off waveforms is solved, and the method has positive significance for high-reliability application occasions.
Description
Technical Field
The utility model relates to a power supply ripple monitors technical field, especially relates to a monitoring circuit of power supply ripple and noise.
Background
In the design of the current board card, a background monitoring circuit is generally designed, so that power supply ripples can be monitored, and whether the ripples meet the use requirements of a chip or not is judged. However, in recent years, because a high-speed signal bus is widely used on a chip, the speed can reach 10Gbps or even 20Gbps, the power supply voltage for supplying power to the high-speed signal bus is lower, and the high-speed signal bus is more sensitive to noise, generally, the power supply is about 1V, the noise tolerance is 3%, and the abnormal conditions such as unstable connection, error codes, flash and the like of the high-speed signal bus can be caused due to the excessive noise of the power supply. Therefore, the conventional circuit design that can only monitor the power supply ripple cannot meet the current requirement. Meanwhile, when the traditional ripple monitoring circuit is powered on and powered off, the power-on and power-off waveforms are transmitted in a penetrating mode with probability, and the risk that the ADC sampling circuit is burnt by high voltage output by a later stage is caused.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome prior art's shortcoming, provide a monitoring circuit of power ripple and noise, solved not enough that traditional circuit exists.
The purpose of the utility model is realized through the following technical scheme: a monitoring circuit for power supply ripple and noise comprises a decoupling circuit, a first-stage filter, a second-stage filter, a high-speed operational amplification circuit, a voltage limiting circuit, a high-speed ADC sampling circuit and a switch circuit; the output end of the decoupling circuit is connected with the input end of the first-stage filter, the output end of the first-stage filter is connected with the input end of the second-stage filter, the output end of the second-stage filter is connected with the input end of the high-speed operational amplification circuit, the output end of the high-speed operational amplification circuit is connected with the input end of the voltage limiting circuit, and the output end of the voltage limiting circuit is connected with the input end of the high-speed ADC acquisition circuit; the output end of the decoupling circuit is also connected with the input end of the switch circuit, and the output end of the switch circuit is connected with the output end of the first-stage filter.
The first-stage filter comprises inductors L1 and L2, and capacitors C1, C2 and C3; the inductors L1 and L2 are connected in series, the output end of the decoupling circuit is connected with the inductor L1, and the inductor L2 is connected with the input end of the second-stage filter; one end of the capacitor C1 is connected with the output end of the decoupling circuit, and the other end of the capacitor C1 is grounded; one end of the capacitor C2 is connected to the connection point of the inductors L1 and L2, and the other end is grounded; one end of the capacitor C3 is connected with the input end of the second stage filter, and the other end is grounded.
The second-stage filter comprises a plurality of stages of LC low-pass filters which are sequentially connected in series, a first inductor is connected to the input end of the first-stage LC low-pass filter, and a second inductor is connected to the output end of the last-stage LC low-pass filter; each stage of LC low-pass filter comprises an inductor and a capacitor connected with the inductor in parallel; the output end of the first-stage filter is connected with the input end of the first inductor, and the output end of the second inductor is connected with the input end of the high-speed operational amplification circuit.
The high-speed operational amplification circuit comprises an operational amplification device, a p input end of the operational amplification device is connected with a resistor R1, an n input end of the operational amplification device is connected with a resistor R2, and the second inductor is connected with a resistor R1; a resistor R3 is connected between the p input terminal and the n output terminal of the operational amplifier device, and a resistor R4 is connected between the n input terminal and the p output terminal.
The decoupling circuit comprises a coupling capacitor C0, and the output end of the coupling capacitor C0 is respectively connected with the input ends of the first-stage filter and the switch circuit; the voltage limiting circuit comprises a voltage stabilizing tube, one end of the voltage stabilizing tube is connected with the output end of the high-speed operational amplification circuit, and the other end of the voltage stabilizing tube is connected with the input end of the high-speed ADC sampling circuit.
The utility model has the advantages of it is following: a monitoring circuit for power supply ripple and noise can monitor the ripple and noise condition of an important power supply in a background and judge the health degree of the power supply; meanwhile, the problem that the sampling ADC is burnt by high voltage caused by power-on and power-off waveforms is solved, and the method has positive significance for high-reliability application occasions.
Drawings
FIG. 1 is a schematic diagram of the principle structure of the present invention;
FIG. 2 is a decoupling circuit diagram;
FIG. 3 is a circuit diagram of a first stage filter;
FIG. 4 is a circuit diagram of a second stage filter;
fig. 5 is a high-speed operational amplifier circuit diagram.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the present application provided below in connection with the appended drawings is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application. The present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1, a power supply ripple and noise monitoring circuit includes a decoupling circuit, a first filter, a second filter, a high-speed operational amplifier circuit, a voltage limiting circuit, a high-speed ADC sampling circuit, and a switch circuit; the output end of the decoupling circuit is connected with the input end of the first-stage filter, the output end of the first-stage filter is connected with the input end of the second-stage filter, the output end of the second-stage filter is connected with the input end of the high-speed operational amplification circuit, the output end of the high-speed operational amplification circuit is connected with the input end of the voltage limiting circuit, and the output end of the voltage limiting circuit is connected with the input end of the high-speed ADC acquisition circuit; the output end of the decoupling circuit is also connected with the input end of the switch circuit, and the output end of the switch circuit is connected with the output end of the first-stage filter.
As shown in fig. 2, the main function of the decoupling circuit is to remove the dc component from the power supply and to retain the ac component, the frequency range of the ac component is generally from a number K to a number G, where a 100nF coupling capacitor is selected to filter the dc component.
As shown in fig. 3, the first stage filter includes inductors L1 and L2, and capacitors C1, C2 and C3; the inductors L1 and L2 are connected in series, the output end of the decoupling circuit is connected with the inductor L1, and the inductor L2 is connected with the input end of the second-stage filter; one end of the capacitor C1 is connected with the output end of the decoupling circuit, and the other end of the capacitor C1 is grounded; one end of the capacitor C2 is connected to the connection point of the inductors L1 and L2, and the other end is grounded; one end of the capacitor C3 is connected with the input end of the second-stage filter, and the other end is grounded.
Further, the primary function of the first stage filter is to filter the ac component above 20M and retain the component below 20M frequency, which is called the power supply ripple part. The second-order butterworth filter is selected here, and the filter is also called a maximum smoothing filter because no ripple exists in the attenuation curve, and the attenuation curve without ripple is very convenient for post-processing. The filter consists of 5 devices in total, L1, L2, C1, C2 and C3 realize the function of low-pass filtering, and the cut-off point of the filter is set at 20 MHz; the model selection of L1 and L2 is 600nH, the model selection of C1 and C3 is 100pF, and the model selection of C2 is 320 pF. The filtered alternating current component is output from the OUT terminal, at the moment, the alternating current component with the frequency more than 20Mhz is greatly attenuated, and the alternating current component with the frequency less than 20Mhz is reserved.
As shown in fig. 4, the second-stage filter includes a plurality of stages of LC low-pass filters connected in series in sequence, a first inductor is connected to an input end of the first-stage LC low-pass filter, and a second inductor is connected to an output end of the last-stage LC low-pass filter; each stage of LC low-pass filter comprises an inductor and a capacitor connected with the inductor in parallel; the output end of the first-stage filter is connected with the input end of the first inductor, and the output end of the second inductor is connected with the input end of the high-speed operational amplification circuit.
Furthermore, the second-stage filter mainly functions to filter alternating current components above 500M, and due to the fact that the cut-off frequency is high, an integrated low-pass filter is selected, the model is LFCG-42+, the pass band is DC-435 Mhz, typical insertion loss is controlled to be below 2dB, noise above 500M in a power circuit can be attenuated, and noise parts needing to be observed are reserved. The OUT of the first stage filter is connected to the RF IN of the second stage filter and is output from the RF OUT.
As shown in fig. 5, the high-speed operational amplifier circuit includes an operational amplifier, a p-input terminal of the operational amplifier is connected to a resistor R1, an n-input terminal of the operational amplifier is connected to a resistor R2, and the second inductor is connected to a resistor R1; a resistor R3 is connected between the p input terminal and the n output terminal of the operational amplifier device, and a resistor R4 is connected between the n input terminal and the p output terminal.
Further, the high-speed operational amplifier circuit is significantly different from the traditional operational amplifier, and since the high-speed ADC at the next stage is generally differential input, it needs to convert the single-ended power ripple noise signal into a differential signal and amplify the differential signal. The RF OUT of the second stage filter is connected with the VIN, and the input N stages are grounded due to single-end to differential conversion. The resistors R1 and R2 are selected to be 499 ohms, the resistors R3 and R4 are selected to be about 4 times amplified according to the amplification factor of the operational amplifier, the resistors R3 and R4 are selected to be 2K, the resistors are converted into differential levels after being amplified, and VOUT _ p and VOUT _ n are connected with a voltage limiting circuit.
Furthermore, the voltage limiting circuit mainly uses a voltage stabilizing tube for limiting voltage, so that the oscillation amplitude of P/N is not too large, such as transparent transmission caused by power-on waveforms and power-off waveforms, and the situation that abnormal waveforms break down the input pin of the rear-stage high-speed sampling ADC is avoided.
Furthermore, the high-speed ADC sampling circuit is mainly an ADC with a selective sampling rate of about 1GSPS, the resolution is more than or equal to 10 bits, analog-to-digital conversion of ripple waves and noise voltage is realized, and converted digital information can be directly reported.
Furthermore, the switch circuit mainly realizes whether the first-stage filter is bypassed, one side of the switch circuit is connected with the input stage of the first-stage filter, and the other side of the switch circuit is connected with the output stage of the first-stage filter; when the power supply noise needs to be sampled, the switch circuit is conducted, the first-stage filter is bypassed, and the noise with the full bandwidth directly enters the second-stage filter, so that the power supply noise is finally sampled by the high-speed ADC. When the power ripple needing to be sampled is disconnected, the full-bandwidth noise enters the first-stage filter, the output signal only contains frequency components of 20M or below, and the power ripple is finally sampled by the high-speed ADC. Such a circuit achieves sampling of ripple and noise.
The utility model discloses a working process as follows: when the power supply noise needs to be sampled, the high-speed ADC sampling circuit conducts the switch circuit, the time delay is about 100mS, sampling is carried out after the signal is stable, and the sampled data are the power supply noise; when the power ripple needs to be sampled, the high-speed ADC sampling circuit disconnects the switch circuit, the time delay is about 100mS, sampling is carried out after signals are stable, and the sampled data are power noise.
The foregoing is illustrative of the preferred embodiments of the present invention, and it is to be understood that the invention is not limited to the precise forms disclosed herein and that the invention is not to be considered as limited to the disclosed embodiments, but is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. A power supply ripple and noise monitoring circuit, comprising: the high-speed operational amplifier circuit comprises a decoupling circuit, a first-stage filter, a second-stage filter, a high-speed operational amplifier circuit, a voltage limiting circuit, a high-speed ADC sampling circuit and a switch circuit; the output end of the decoupling circuit is connected with the input end of the first-stage filter, the output end of the first-stage filter is connected with the input end of the second-stage filter, the output end of the second-stage filter is connected with the input end of the high-speed operational amplification circuit, the output end of the high-speed operational amplification circuit is connected with the input end of the voltage limiting circuit, and the output end of the voltage limiting circuit is connected with the input end of the high-speed ADC acquisition circuit; the output end of the decoupling circuit is also connected with the input end of the switch circuit, and the output end of the switch circuit is connected with the output end of the first-stage filter.
2. A supply ripple and noise monitoring circuit according to claim 1, wherein: the first-stage filter comprises inductors L1 and L2, and capacitors C1, C2 and C3; the inductors L1 and L2 are connected in series, the output end of the decoupling circuit is connected with the inductor L1, and the inductor L2 is connected with the input end of the second-stage filter; one end of the capacitor C1 is connected with the output end of the decoupling circuit, and the other end of the capacitor C1 is grounded; one end of the capacitor C2 is connected to the connection point of the inductors L1 and L2, and the other end is grounded; one end of the capacitor C3 is connected with the input end of the second stage filter, and the other end is grounded.
3. A supply ripple and noise monitoring circuit according to claim 2, wherein: the second-stage filter comprises a plurality of stages of LC low-pass filters which are sequentially connected in series, a first inductor is connected to the input end of the first-stage LC low-pass filter, and a second inductor is connected to the output end of the last-stage LC low-pass filter; each stage of LC low-pass filter comprises an inductor and a capacitor connected with the inductor in parallel; the output end of the first-stage filter is connected with the input end of the first inductor, and the output end of the second inductor is connected with the input end of the high-speed operational amplification circuit.
4. A supply ripple and noise monitoring circuit according to claim 3, wherein: the high-speed operational amplification circuit comprises an operational amplification device, a p input end of the operational amplification device is connected with a resistor R1, an n input end of the operational amplification device is connected with a resistor R2, and the second inductor is connected with a resistor R1; a resistor R3 is connected between the p input terminal and the n output terminal of the operational amplifier, and a resistor R4 is connected between the n input terminal and the p output terminal.
5. A supply ripple and noise monitoring circuit according to claim 2, wherein: the decoupling circuit comprises a coupling capacitor C0, and the output end of the coupling capacitor C0 is respectively connected with the input ends of the first-stage filter and the switch circuit; the voltage limiting circuit comprises a voltage stabilizing tube, one end of the voltage stabilizing tube is connected with the output end of the high-speed operational amplification circuit, and the other end of the voltage stabilizing tube is connected with the input end of the high-speed ADC sampling circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220528055.XU CN217060453U (en) | 2022-03-11 | 2022-03-11 | Monitoring circuit for power supply ripple and noise |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220528055.XU CN217060453U (en) | 2022-03-11 | 2022-03-11 | Monitoring circuit for power supply ripple and noise |
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| Publication Number | Publication Date |
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| CN217060453U true CN217060453U (en) | 2022-07-26 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202220528055.XU Active CN217060453U (en) | 2022-03-11 | 2022-03-11 | Monitoring circuit for power supply ripple and noise |
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| CN (1) | CN217060453U (en) |
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- 2022-03-11 CN CN202220528055.XU patent/CN217060453U/en active Active
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