CN203225652U - Circuit for reducing ripple waves and suppressing noise for adjustable precision direct current large current source - Google Patents

Abstract

Disclosed is a circuit for reducing ripple waves and suppressing noise for an adjustable precision direct current large current source. An iron core TA and an iron core TB of the circuit are overlapped up and down to form a double iron core structure. A Hall probe is arranged inside the iron core TA, the Hall probe is connected with a lowpass filtering circuit, the lowpass filtering circuit is connected with a pre-amplification electric circuit with gain adjustment, the pre-amplification electric circuit with the gain adjustment is connected with a constant flow source circuit, the constant flow source circuit is connected with an N2 winding of the iron core TB, and one end of an N1 winding is directly connected with the other end of the N2 winding. An N3 winding of the iron core TA is connected with a ripple wave and noise extraction circuit, the ripple wave and noise extraction circuit is connected with a pre-amplification electric circuit with gain and phase adjustment, the pre-amplification electric circuit with the gain and phase adjustment is connected with a power amplification circuit, and the power amplification circuit is connected with an N4 winding of the iron core TB. By means of the circuit for reducing the ripple waves and suppressing the noise for the adjustable precision direct current large current source, the content of the ripple waves and the content of the noise are reduced to be lower than 0.1%, the measurement performance of products is good in consistence and repeatability, the products are stable and reliable, and the circuit is suitable for the large current source with the wide range.

Description

Be used for the reduction ripple in adjustable precision D.C. high-current source and suppress the noise circuit

Technical field

The utility model relates to a kind of reduction ripple for adjustable precision D.C. high-current source and suppresses the noise circuit, belongs to the electric energy metrical field.

Background technology

Can regulate the big current source of precision DC and generally be divided into two kinds of linear power supply and Switching Power Supplies, linear power supply is because of its manufacturing cost height, the low seldom employing of efficient, therefore big current source generally adopts Switching Power Supply to realize, but distinct issues are that high-frequency noise, ripple are big when Switching Power Supply is applied to accurate measurement.Ripple and generating noise are comparatively complicated, are mainly derived from following several respects: ripple and noise that the hyperfrequency resonance noise that produces in the common mode ripple that input low-frequency ripple, parasitic parameter cause and noise, the power device switching process and closed-loop adjustment control cause.The method that suppresses ripple and noise at present mainly contains:

(1) improves the Switching Power Supply operating frequency, to improve the frequency of ripple and noise, be conducive to the inhibition of filter network;

(2) use the passive filtering network;

(3) with the linear circuit of adjusting of plural serial stage;

(4) reasonable line arrangement, transformer will suitably shield, and ground connection is wanted in shielding;

(5) with some transient protective devices.

Because the size of ripple and noise is relevant with the operating frequency of Switching Power Supply, can reduce ripple and noise by the operating frequency that improves Switching Power Supply, corresponding the reducing of adjusting fineness of while current source, and electric energy meter calibrating apparatus requires the adjusting fineness to be better than 0.002% ^*The range value.Passive filter is bulky, and is expensive; For inductance, D.C. high-current is easy to make it saturated and filtering was lost efficacy; Electric capacity the ripple current that can pass through be limited.The D.C. high-current source is as adopting the linear circuit of adjusting, and has also that energy loss is big, efficient is low, cost is high and shortcoming such as control complexity.Prior art is the passive adaptation type basically.

Summary of the invention

The utility model provides a kind of reduction ripple for adjustable precision D.C. high-current source and has suppressed the noise circuit, and it can effectively suppress to regulate ripple and the noise of the big current source of precision DC, and the content of ripple and noise is reduced to below 0.1%.

The utility model is by achieving the above object by the following technical solutions: a kind of reduction ripple and inhibition noise circuit for adjustable precision D.C. high-current source, the iron core T of this circuit _AAnd T _BStack up and down and form double-iron core structure, iron core T _AA built-in hall probe, hall probe connects low-pass filter circuit, the pre-amplification circuit of low-pass filter circuit connecting band gain-adjusted, the pre-amplification circuit of band gain-adjusted connects constant-current source circuit, and constant-current source circuit connects T _BThe N2 winding, an end of N1 winding directly links to each other with the other end of N2 winding.Iron core T _AThe N3 winding connect ripple and noise extraction circuit, ripple and the gain of noise extraction circuit connecting band and phase-adjusted pre-amplification circuit, the band gain is connected power amplification circuit with phase-adjusted pre-amplification circuit, power amplification circuit connection iron core T _BThe N4 winding.

Described iron core T _AWith iron core T _BAmorphous or nanocrystalline material by high permeability are made.

Described low-pass filter circuit is made up of resistance R 1, capacitor C 1, resistance R 2 and capacitor C 2, one end of resistance R 1 connects hall probe, the other end connects capacitor C 1 and resistance R 2, one end of capacitor C 1 connects resistance R 1 and resistance R 2, other end ground connection, one end of resistance R 2 connects capacitor C 1 and resistance R 1, and the other end connects the pre-amplification circuit of capacitor C 2 and band gain-adjusted.

The pre-amplification circuit of described band gain-adjusted is made up of resistance R 3, resistance R 4 and operational amplifier A 1, resistance R 3 one ends connect low-pass filter circuit, the other end connects the inverting input of resistance R 4 and operational amplifier A 1, inverting input and the output of resistance R 4 concatenation operation amplifier A1, the positive input end grounding of operational amplifier A 1, output connects constant-current source circuit.

Described constant-current source circuit is made up of resistance R 5, resistance R 6 and operational amplifier A 2, the pre-amplification circuit of one end connecting band gain-adjusted of resistance R 5, the normal phase input end of other end concatenation operation amplifier A2, inverting input and the winding N1 of one end concatenation operation amplifier A2 of resistance R 6, other end ground connection, the output of operational amplifier A 2 connects winding N2.

Described ripple and noise extraction circuit are by resistance R 7, resistance R 8, resistance R 9, resistance R 10 and operational amplifier A 3 are formed, one end of resistance R 7 connects winding N3, the other end connects the inverting input of resistance R 9 and operational amplifier A 3, one end of resistance R 8 connects winding N3, the other end connects the normal phase input end of resistance R 10 and operational amplifier A 3, one end of resistance R 10 connects the normal phase input end of resistance R 8 and operational amplifier A 3, other end ground connection, one end of resistance R 9 connects the inverting input of resistance R 7 and operational amplifier A 3, the output of other end concatenation operation amplifier A3, the gain of output connecting band and the phase-adjusted pre-amplification circuit of operational amplifier A 3.

Described band gain and phase-adjusted pre-amplification circuit are by resistance R 11, resistance R 12, resistance R 13, capacitor C 3 and operational amplifier A 4 are formed, one end of resistance R 11 connects ripple and noise extraction circuit and capacitor C 3, the other end connects the inverting input of resistance R 13 and operational amplifier A 4, one end of capacitor C 3 connects ripple and noise extraction circuit and resistance R 11, the other end connects the normal phase input end of resistance R 12 and operational amplifier A 4, one end of resistance R 12 connects the normal phase input end of capacitor C 3 and operational amplifier A 4, other end ground connection, one end of resistance R 13 connects the inverting input of resistance R 11 and operational amplifier A 4, the output of other end concatenation operation amplifier A4, the output of operational amplifier A 4 connects power amplification circuit.

Described power amplification circuit is made up of resistance R 14, resistance R 15 and operational amplifier A 5, the gain of one end connecting band and the phase-adjusted pre-amplification circuit of resistance R 14, the other end connects the inverting input of resistance R 15 and operational amplifier A 5, the positive input end grounding of operational amplifier A 5, output connects resistance R 15 and winding N4.

Described reduction ripple and the control method that suppresses the noise circuit for adjustable precision D.C. high-current source comprise the steps:

DC current source output signal I _PPass the identical iron core T of material that stacks simultaneously _AWith iron core T _B, I _PAt iron core T _AIn induce magnetic field B, detect and I by hall probe _PThe voltage signal that is directly proportional is isolated direct current component in the magnetic field B by low-pass filter circuit again, utilizes the pre-amplification circuit of band gain-adjusted and constant-current source circuit to produce direct current I ₁Drive iron core T _AN1 and iron core T _BThe N2 winding, when satisfying N1=N2=I _-÷ I ₁During condition, iron core T _AWith iron core T _BIn D.C. magnetic field be 0, prevent from effectively taking place because D.C. high-current causes iron core magnetic saturation phenomenon with this; Iron core T _AWinding N3 be coupled out DC current source I _PIn ripple and noise current, by band gain and phase-adjusted preposition amplification and power amplification, be loaded into iron core T _BThe N4 winding on, work as I _2～=I _～During ÷ N4, I _P=I _-, ripple and noise in the DC current source have just disappeared, thereby have reached the purpose that suppresses ripple, reduces noise.

Described D.C. high-current source is the adjustable current source of 1mA-600A, and the changing value of electric current is less than 0.005% in 5 minutes, and under unloaded and full-load conditions, ripple and noise content should be lower than 0.1%.

Principle of the present utility model is:

Output current signal (the I of DC current source _P) can be expressed as:

I _P＝I _-+I _～

I _POutput current signal for DC current source.

I _-Be the direct current component in the output current signal of DC current source.

I _～Be the AC portion in the output current signal of DC current source, characterize with the effective value electric current.

$I_{~}=\sqrt{{\left(I_{R~}\right)}^2+{\left(I_{N~}\right)}^2}$

I _{R ~}Be the low-frequency ripple in the output current signal of DC current source, characterize with the effective value electric current.

I _{N ~}Be the high-frequency noise in the output current signal of DC current source, characterize with the effective value electric current.

Ripple and noise suppressed ratio $K_{\mathrm{NRR}}=\frac{I_{~}}{I_{-}}\×100\%.$

Outstanding advantage of the present utility model is:

(1) with the way of initiatively eliminating ripple and noise, the content of ripple and noise is reduced to below 0.1%, improved big current stability, widely.

(2) product measurement performance consistency, good reproducibility, stable, reliable, be applicable to the big current source of wide region.

Description of drawings

Fig. 1 is the reduction ripple for adjustable precision D.C. high-current source described in the utility model and suppresses the noise circuit.

Fig. 2 is the reduction ripple for adjustable precision D.C. high-current source described in the utility model and suppresses components and parts annexation figure between noise circuit N1 winding and the N2 winding.

Fig. 3 is the reduction ripple for adjustable precision D.C. high-current source described in the utility model and suppresses components and parts annexation figure between noise circuit N3 winding and the N4 winding.

Embodiment

Below by accompanying drawing and example the technical solution of the utility model is further specified.

As shown in Figure 1, be used for the reduction ripple in adjustable precision D.C. high-current source and suppress the noise circuit, by iron core T _A, iron core T _B, hall probe, low-pass filter circuit, band gain-adjusted pre-amplification circuit, constant-current source circuit, N1 winding, N2 winding, N3 winding, N4 winding, ripple and noise extraction circuit, band gain and phase-adjusted pre-amplification circuit and power amplification circuit form iron core T _AWith iron core T _BStack up and down and form double-iron core structure, iron core T _AA built-in hall probe, hall probe connects low-pass filter circuit, the pre-amplification circuit of low-pass filter circuit connecting band gain-adjusted, the pre-amplification circuit of band gain-adjusted connects constant-current source circuit, and constant-current source circuit connects T _BThe N2 winding, an end of N1 winding directly links to each other with the other end of N2 winding.Iron core T _AThe N3 winding connect ripple and noise extraction circuit, ripple and the gain of noise extraction circuit connecting band and phase-adjusted pre-amplification circuit, the band gain is connected power amplification circuit with phase-adjusted pre-amplification circuit, power amplification circuit connection iron core T _BThe N4 winding.

Described iron core T _AWith iron core T _BAmorphous or nanocrystalline material by high permeability are made.

Described low-pass filter circuit is made up of resistance R 1, capacitor C 1, resistance R 2 and capacitor C 2, one end of resistance R 1 connects hall probe, the other end connects capacitor C 1 and resistance R 2, one end of capacitor C 1 connects resistance R 1 and resistance R 2, other end ground connection, one end of resistance R 2 connects capacitor C 1 and resistance R 1, and the other end connects the pre-amplification circuit of capacitor C 2 and band gain-adjusted.

The pre-amplification circuit of described band gain-adjusted is made up of resistance R 3, resistance R 4 and operational amplifier A 1, resistance R 3 one ends connect low-pass filter circuit, the other end connects the inverting input of resistance R 4 and operational amplifier A 1, inverting input and the output of resistance R 4 concatenation operation amplifier A1, the positive input end grounding of operational amplifier A 1, output connects constant-current source circuit.

Described constant-current source circuit is made up of resistance R 5, resistance R 6 and operational amplifier A 2, the pre-amplification circuit of one end connecting band gain-adjusted of resistance R 5, the normal phase input end of other end concatenation operation amplifier A2, inverting input and the winding N1 of one end concatenation operation amplifier A2 of resistance R 6, other end ground connection, the output of operational amplifier A 2 connects winding N2.

Described ripple and noise extraction circuit are by resistance R 7, resistance R 8, resistance R 9, resistance R 10 and operational amplifier A 3 are formed, one end of resistance R 7 connects winding N3, the other end connects the inverting input of resistance R 9 and operational amplifier A 3, one end of resistance R 8 connects winding N3, the other end connects the normal phase input end of resistance R 10 and operational amplifier A 3, one end of resistance R 10 connects the normal phase input end of resistance R 8 and operational amplifier A 3, other end ground connection, one end of resistance R 9 connects the inverting input of resistance R 7 and operational amplifier A 3, the output of other end concatenation operation amplifier A3, the gain of output connecting band and the phase-adjusted pre-amplification circuit of operational amplifier A 3.

Described band gain and phase-adjusted pre-amplification circuit are by resistance R 11, resistance R 12, resistance R 13, capacitor C 3 and operational amplifier A 4 are formed, one end of resistance R 11 connects ripple and noise extraction circuit and capacitor C 3, the other end connects the inverting input of resistance R 13 and operational amplifier A 4, one end of capacitor C 3 connects ripple and noise extraction circuit and resistance R 11, the other end connects the normal phase input end of resistance R 12 and operational amplifier A 4, one end of resistance R 12 connects the normal phase input end of capacitor C 3 and operational amplifier A 4, other end ground connection, one end of resistance R 13 connects the inverting input of resistance R 11 and operational amplifier A 4, the output of other end concatenation operation amplifier A4, the output of operational amplifier A 4 connects power amplification circuit.

Described power amplification circuit is made up of resistance R 14, resistance R 15 and operational amplifier A 5, the gain of one end connecting band and the phase-adjusted pre-amplification circuit of resistance R 14, the other end connects the inverting input of resistance R 15 and operational amplifier A 5, the positive input end grounding of operational amplifier A 5, output connects resistance R 15 and winding N4.

As shown in Figure 2, be used for the reduction ripple in adjustable precision D.C. high-current source and suppress components and parts annexation figure between noise circuit N1 winding and the N2 winding.DC current source output signal I _PPass the identical iron core T of material that stacks simultaneously _AWith iron core T _B, I _PAt iron core T _AIn induce magnetic field B, detect and I by hall probe _PThe voltage signal that is directly proportional, the low-pass filter circuit of forming by R1, C1, R2 and C2 is isolated the direct current component in the magnetic field B again.The pre-amplification circuit of the band gain-adjusted that utilization is made up of R3, R4 and A1 and produce direct current I by the constant-current source circuit that R5, R6 and A2 form ₁Drive iron core T _AN1 and iron core T _BThe N2 winding, when satisfying N1=N2=I _-÷ I ₁During condition, iron core T _AWith iron core T _BIn D.C. magnetic field be 0, can prevent from effectively this moment taking place because D.C. high-current causes iron core magnetic saturation phenomenon.

As shown in Figure 3, be used for the reduction ripple in adjustable precision D.C. high-current source and suppress components and parts annexation figure between noise circuit N3 winding and the N4 winding.Iron core T _AWinding N3 be coupled out DC current source I _PIn ripple and noise current, ripple and noise extraction circuit by R7, R8, R9, R10 and A3 composition, the band gain that R11, R12, R13, C3 and A4 form and phase-adjusted pre-amplification circuit and the power amplification circuit that R14, R15 and A5 form are loaded into iron core T _BThe N4 winding on, work as I _2～=I _～During ÷ N4, I _P=I _-, ripple and noise in the DC current source have just disappeared, thereby have reached the purpose that suppresses ripple, reduces noise.

Claims (8)

1. be used for the reduction ripple in adjustable precision D.C. high-current source and suppress the noise circuit, it is characterized in that the iron core T of this circuit _AAnd T _BStack up and down and form double-iron core structure, iron core T _AA built-in hall probe, hall probe connects low-pass filter circuit, the pre-amplification circuit of low-pass filter circuit connecting band gain-adjusted, the pre-amplification circuit of band gain-adjusted connects constant-current source circuit, and constant-current source circuit connects T _BThe N2 winding, an end of N1 winding directly links to each other with the other end of N2 winding; Iron core T _AThe N3 winding connect ripple and noise extraction circuit, ripple and the gain of noise extraction circuit connecting band and phase-adjusted pre-amplification circuit, the band gain is connected power amplification circuit with phase-adjusted pre-amplification circuit, power amplification circuit connection iron core T _BThe N4 winding.

2. reduction ripple and inhibition noise circuit for adjustable precision D.C. high-current source according to claim 1 is characterized in that described iron core T _AWith iron core T _BAmorphous or nanocrystalline material by high permeability are made.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, described low-pass filter circuit is made up of resistance R 1, capacitor C 1, resistance R 2 and capacitor C 2, one end of resistance R 1 connects hall probe, the other end connects capacitor C 1 and resistance R 2, one end of capacitor C 1 connects resistance R 1 and resistance R 2, other end ground connection, one end of resistance R 2 connects capacitor C 1 and resistance R 1, and the other end connects the pre-amplification circuit of capacitor C 2 and band gain-adjusted.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, the pre-amplification circuit of described band gain-adjusted is made up of resistance R 3, resistance R 4 and operational amplifier A 1, resistance R 3 one ends connect low-pass filter circuit, the other end connects the inverting input of resistance R 4 and operational amplifier A 1, inverting input and the output of resistance R 4 concatenation operation amplifier A1, the positive input end grounding of operational amplifier A 1, output connects constant-current source circuit.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, described constant-current source circuit is made up of resistance R 5, resistance R 6 and operational amplifier A 2, the pre-amplification circuit of one end connecting band gain-adjusted of resistance R 5, the normal phase input end of other end concatenation operation amplifier A2, inverting input and the winding N1 of one end concatenation operation amplifier A2 of resistance R 6, other end ground connection, the output of operational amplifier A 2 connects winding N2.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, described ripple and noise extraction circuit are by resistance R 7, resistance R 8, resistance R 9, resistance R 10 and operational amplifier A 3 are formed, one end of resistance R 7 connects winding N3, the other end connects the inverting input of resistance R 9 and operational amplifier A 3, one end of resistance R 8 connects winding N3, the other end connects the normal phase input end of resistance R 10 and operational amplifier A 3, one end of resistance R 10 connects the normal phase input end of resistance R 8 and operational amplifier A 3, other end ground connection, one end of resistance R 9 connects the inverting input of resistance R 7 and operational amplifier A 3, the output of other end concatenation operation amplifier A3, the gain of output connecting band and the phase-adjusted pre-amplification circuit of operational amplifier A 3.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, described band gain and phase-adjusted pre-amplification circuit are by resistance R 11, resistance R 12, resistance R 13, capacitor C 3 and operational amplifier A 4 are formed, one end of resistance R 11 connects ripple and noise extraction circuit and capacitor C 3, the other end connects the inverting input of resistance R 13 and operational amplifier A 4, one end of capacitor C 3 connects ripple and noise extraction circuit and resistance R 11, the other end connects the normal phase input end of resistance R 12 and operational amplifier A 4, one end of resistance R 12 connects the normal phase input end of capacitor C 3 and operational amplifier A 4, other end ground connection, one end of resistance R 13 connects the inverting input of resistance R 11 and operational amplifier A 4, the output of other end concatenation operation amplifier A4, the output of operational amplifier A 4 connects power amplification circuit.

According to claim 1 for adjustable precision D.C. high-current source the reduction ripple and suppress the noise circuit, it is characterized in that, described power amplification circuit is made up of resistance R 14, resistance R 15 and operational amplifier A 5, the gain of one end connecting band and the phase-adjusted pre-amplification circuit of resistance R 14, the other end connects the inverting input of resistance R 15 and operational amplifier A 5, the positive input end grounding of operational amplifier A 5, output connects resistance R 15 and winding N4.

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