CN1745315A - MRI precision gradient amplifier with multiple output voltage levels - Google Patents
MRI precision gradient amplifier with multiple output voltage levels Download PDFInfo
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- 238000002595 magnetic resonance imaging Methods 0.000 abstract description 6
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
- G01R33/385—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using gradient magnetic field coils
- G01R33/3852—Gradient amplifiers; means for controlling the application of a gradient magnetic field to the sample, e.g. a gradient signal synthesizer
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Abstract
A controlled power supply (201, 222) drives a magnetic field gradient coil (161) of a magnetic resonance imaging apparatus (10). A gradient amplifier (201) includes a plurality of switching power regulators (50, 52, 54, 56) which are electrically connected in series. A bipolar circuit (70) receives power from the series connected switching power regulators (50, 52, 54, 56) and delivers the power at a selected polarity to the gradient coil (161). A control circuit (221) delivers phase staggered pulse width modulated control signals (A, B, C, D) to the switching power regulators (50, 52, 54, 56).
Description
The present invention relates to the diagnosing image field.Particularly, relate to the controlled source of the magnetic field gradient coils that is used for driving magnetic resonance imagine scanner, and will describe the present invention with particular reference to it.But, in general, the present invention relates to be used for the precisely controlled power supply of various application.
In magnetic resonance imaging system, normally carry out space encoding by in main magnetic core, producing magnetic field gradient.These gradients form by one group of magnetic field gradient coils.Usually, providing gradient coil is to be used for forming independently magnetic field gradient on each direction of x, y and z direction.
Mr imaging technique such as echo-planar imaging use high field intensity, i.e. the magnetic field gradient waveforms of high frequency.In addition, the gradient slew rate of magnetic field gradient, waveform, amplitude and other parameter alter a great deal for dissimilar imaging sequences.Therefore, the magnetic field gradient coils power supply should provide any power waveform under big voltage (for example, crest voltage is 100 volts or higher), big electric current (for example, hundreds of ampere) and high frequency (for example, a per second hundreds of cycle) high conversion rate.And this power supply should be able to provide or ABSORPTION CURRENT under bipolar voltage (4 quadrant operation).
Usually, the pwm switch amplifier is used in the magnetic field gradient power supplies.The pulse-width modulation control signal that triggers by the carrier signal of vibrating under about 40kHz frequency is with frequency of carrier signal switch power supply, to provide width modulation power to gradient coil.By gradient coil intrinsic low-frequency filter characteristics eliminated oscillation of power under carrier frequency.Half-bridge and full-bridge pulse width modulation amplifier all are used.
These amplifiers comprise transistor unit, and they should satisfy strict voltage, electric current and speed (frequency) requirement.For example, these transistors should have the maximum rated voltage that surpasses the maximum voltage that offers gradient coil, and the maximum rated frequency that surpasses carrier frequency.
Another shortcoming of this switching amplifier is, the performance number that no matter they provided and between full voltage (plus or minus) and no-voltage, changing, and this is to be controlled by duty of ratio owing to power, rather than control by amplitude.High frequency conversion between full voltage and no-voltage can be brought harmonic distortion, big problems such as ripple current, a large amount of heats in the gradient coil and Radio frequency interference (RFI), and these can reduce the performance of other element in the magnetic resonance imaging system.
The objective of the invention is to provide a kind of equipment and method of having improved, it has overcome limitation above-mentioned and other problem.
According to an aspect, a kind of controlled source that is used to drive the magnetic field gradient coils of MR imaging apparatus is disclosed.A plurality of switch power regulators are electrically connected with the series connection form, in order to provide power to this gradient coil.Control circuit provides the pulse-width modulation control signal of phase shifting to the switch power regulator.
According to another aspect, provide a kind of method of controlled power that provide to the magnetic field gradient coils of MR imaging apparatus.Produce the pulse-width modulation control signal of phase shifting.Produce a plurality of switch power outputs.By each switch power output of one in the pulse-width modulation control signal of phase shifting conversion.This switch power output of tandem compound.Provide the switch power of tandem compound to export to gradient coil.
According to another aspect, a kind of equipment that is used for controlled power is offered the magnetic field gradient coils of MR imaging apparatus is disclosed.Be provided for producing the device of the pulse-width modulation control signal of phase shifting.Be provided for producing the device of a plurality of switch power outputs, each in exporting by these a plurality of switch powers of one in the pulse-width modulation control signal of phase shifting conversion.Be provided for the device of this switch power output of tandem compound.Be provided for providing the switch power of tandem compound to export to the device of gradient coil.
Advantage is the voltage loads that reduces on the high speed transistor of power amplifier.
Another advantage is can obtain the power output of higher frequency and can correspondingly not increase switching frequency.
Another advantage is to reduce harmonic distortion and ripple current.
Reading on the basis of ensuing detailed description of the preferred embodiment, many other advantage and benefits all will become clearly to those of ordinary skill in the art.
The present invention can adopt the set-up mode of various elements and element, and adopts the set-up mode of various process operations and process operation.Accompanying drawing only is for preferred embodiment is described and should not be construed as is limitation of the present invention.
Fig. 1 shows the MR imaging apparatus of using multistage magnetic field gradient amplifier.
Fig. 2 shows the circuit of a magnetic field gradient amplifier in the imaging device shown in Figure 1.
Fig. 3 shows the circuit of a magnetic field gradient controller in the imaging device shown in Figure 1.
Fig. 4 shows the low output voltage switching manipulation of the magnetic field gradient power supplies shown in Fig. 2 and 3 with graphical method.
Fig. 5 shows the intermediate voltage output switching manipulation of the magnetic field gradient power supplies shown in Fig. 2 and 3 with graphical method.
Fig. 6 shows the intermediate voltage output switching manipulation of the magnetic field gradient power supplies shown in Fig. 2 and 3 with graphical method, and output voltage wherein is higher than the output voltage among Fig. 5.
Fig. 7 shows the high output voltage switching manipulation of the magnetic field gradient power supplies shown in Fig. 2 and 3 with graphical method.
With reference to figure 1, magnetic resonance imagine scanner 10 comprises cylindrical main magnet 12, preferably, this main magnet 12 be superconduction and be (cryoshrouded) that low temperature covers.Main magnet 12 limits a magnetic core 14, is placed with patient or other imaging object that is used for imaging in these magnetic core 14 inside.Constant and the uniform main field on room and time that main magnet 12 produces along magnetic core 14 longitudinal axis.Replace superconducting magnet, can use the non-superconducting magnet.In addition, replace the horizontal cylindrical master magnet 12 illustrated, can also adopt the main magnet of vertical magnets, opening magnet or other type.
Magnetic field gradient coils 16 produces magnetic field gradient in magnetic core 14, be used for spatially the coding magnetic resonance signal and be used for producing magnetization damaging (magnetization-spoiling) field gradient or analogue.Preferably, magnetic field gradient coils 16 comprises the coil that is formed in generation magnetic field gradient on three orthogonal directionss, and these three orthogonal directionss comprise the y direction parallel with main field.
Whole-body radio frequency coil assembly 18 produces the radio-frequency pulse that is used for excite magnetic resonances.This radio frequency coil assemblies 18 also is used for detected magnetic resonance signal.Randomly, also comprise additional local radio frequency coil or phasing radio frequency coil arrays (not shown), to be used to encourage and/or detect the magnetic resonance of regional area in the magnetic core 14.
Be preferably digital radio frequency sending set 24 provide radio-frequency pulse or pulse train to radio frequency coil assemblies 18 to produce selected magnetic resonance excitation.Also be coupled to radio-frequency transmitter 26 receiving magnetic resonance signals on the radio frequency coil assemblies 18.Surpass one radio-frequency coil (as local coil or phasing coil array) if provide, then can select for use different coils to be used for magnetic resonance excitation and detecting operation arbitrarily.
In order to obtain the magnetic resonance imaging data of object, this object is placed in the inside of magnetic core 14, preferably in the isocenter of main field or near this isocenter.Sequence controller 30 and gradient controller 22 and radio frequency sending set 24 communicate to produce selected transient state or steady state magnetic resonance configurations in object, spatially this magnetic resonance is encoded, in order to damage magnetic resonance selectively, perhaps produce the selected magnetic resonance signal feature of object.The magnetic resonance signal that produces is detected by radio-frequency transmitter 26, and is stored in the k space memories 34.Rebuild these imaging datas by reconstruction processor 36, be stored in graphical representation in the video memory 38 with generation.In a suitable embodiment, reconstruction processor 36 is carried out inverse fourier transform and is rebuild.
Handle the result images that obtains by image-signal processor 40 and represent that be presented on the user interface 42, this user interface is the computing machine of personal computer, workstation or other type preferably.Except producing video image, can also handle this graphical representation by printer driver, and on computer network or the Internet or similar network, print, transmit this graphical representation.Preferably, user interface 42 also allows radiologist or other operator and resonance controller 30 to communicate to select the magnetic resonance imaging sequence, revise imaging sequence, to carry out imaging sequence etc.
With reference to figure 2, independent gradient pulse amplifier 20
1 Control gradient coil 16
1This gradient coil 16
1Be in the gradient coil 16 shown in Fig. 1, and this gradient pulse amplifier 20
1Be in the gradient pulse amplifier 20 shown in Fig. 1.Typically, gradient coil 16
1Be in x direction, y direction or vertically produce in a pair of gradient coil of selected magnetic field gradient one on the z direction.
Under high pressure conditions, transistor 60 conductings and transistor 62 not conductings.Like this with voltage V
InBe applied on the transistor 62 of not conducting.Under low-pressure state, transistor 60 not conductings and transistor 62 conductings.On transistor 62, obtain output.The output of four switch power regulators 50,52,54,56 be connected in series (noticing that the bottom output terminal of power governor 52 is connected with the top output terminal of power governor 54, represented) as passing through tie point S.
Therefore, the power governor 50,52,54,56 that is connected in series is according to one in five voltage levels of the common generation of the state of pulse-width modulation control signal A, B, C, D: 0V, V
In, 2V
In, 3V
InOr 4V
InThe power governor 50,52,54,56 that is connected in series provides V jointly
InVoltage resolution, it is the maximum output voltage 4V of voltage
In1/4th.
Bipolar circuit 70 receives the output of the power governor 50,52,54,56 that is connected in series.In the illustrated embodiment, bipolar circuit 70 is full-bridge amplifiers, and it comprises two pairs of igbts 72,74.Bipolar circuit 70 imposes on magnetic field gradient coils 16 with selected polarity with the output of the power governor 50,52,54,56 that is connected in series
1
Particularly, input P, the N that imposes on transistor 72,74 respectively selects polarity.Input N is applied on the transistor 74 that is in not on-state if input P is applied on the transistor 72 that is in conducting state, and first polarity then is provided.Input N is applied on the transistor 74 that is in conducting state if input P is applied on the transistor 72 that is in not on-state, then provides and first opposite polarity second polarity.Preferably, ammeter 76 is measured the electric current that flows through magnetic field gradient coils 161.
At amplifier 20
1In, provide polarity to select by the bipolar circuit of opening in 50,52,54,56 minutes with power governor 70.As will be discussed later, this setup has certain advantage.But, also can consider polarity is selected to combine with power governor 50,52,54,56, for example by replace half-bridge power regulator 50,52,54,56 with the full bridge power regulator.
With reference to figure 3, by magnetic field gradient controller 22
1Produce pulse-width modulation control signal A, B, C, D.This magnetic field gradient controller 22
1Be in the gradient controller 22 shown in Fig. 1, and with Fig. 2 in gradient pulse amplifier 20
1With gradient coil 16
1Be associated.
Exchange the frequency that carrier signal 80 limits pulse-width modulation control signal A, B, C, D.In a suitable embodiment, this exchanges carrier signal 80 and vibrates with 40kHz.Phase-shift circuit 82,84,86 will exchange 90 °, 180 ° and 270 ° of the phase place phase shifts of carrier signal 80 respectively.This carrier signal 80 is imported into pulse width modulator 90, and the output of phase-shift circuit 82,84,86 is imported into pulse width modulator 92,94,96.Each pulse width modulator 90,92,94,96 produces has the frequency that limited by input carrier signal and the train of impulses of phase place.This train of impulses is pulse-width modulation control signal A, B, C, D, so 90 ° of intervals of the phase shifting of control signal A, B, C, D.
Feedback controller 100 is set point 102 and measurement gradient coil 16 relatively
1The output of the ammeter 76 of middle electric current.Be imported into pulse width modulator 90,92,94,96 by controller 100 according to the control signal that comparative result produces, and control the pulse width of the pulse of control signal A, B, C, D.Typically, provide set point 102 according to the desired required magnetic field gradient of imaging sequence by sequence controller 30 (referring to Fig. 1).It should be understood that set point 102 dynamically changes, and for example changes along with the rotation of magnetic field gradient.In addition, other feedback signal except that gradient coil current can be used to control, as gradient coil voltage or by gradient coil 16
1The measurement characteristics of the magnetic field gradient that produces.
Continue with reference to figure 2-3, and, describe gradient controller 22 further with reference to figure 4-7
1With gradient amplifier 20
1Operation.The bottom of each in Fig. 4-7 shows pulse-width modulation control signal A, B, C, D.The top of each in Fig. 4-7 is 0 to 4V
InScope in draw and offer the output voltage of bipolar circuit 70 by the switch power regulator 50,52,54,56 that is connected in series.In in Fig. 4-7 each, the period T that exchanges carrier signal 80 is shown
CarrierFor the carrier frequency of 40kHz, T
Carrier=0.025ms.Among Fig. 4-7 each further comprises the horizontal ordinate of the phase place of expressing this interchange carrier signal 80.
Fig. 4 shows the course of work that feedback controller 100 produces corresponding to the control signal of short pulse width.Particularly, among Fig. 4 the dutycycle of pulse-width modulation control signal A, B, C, D less than 25%.Because 90 ° of (that is carrier cycle T, of phase shifting
Carrier25%), so the pulse of four control signal A, B, C, D in time can be not overlapping.Therefore, output voltage 110 is discretely at zero volt and V
InBetween change.
It should be noted that the cycle of output voltage 110 is carrier cycle T
Carrier1/4th.Therefore, the frequency of output voltage 110 is four times of carrier frequency.This is the result of phase shifting.By magnetic field gradient coils 16
1Intrinsic low-pass filtering effect filtering the radio-frequency component in the output voltage 110.
Fig. 5 shows the course of work that feedback controller 100 produces corresponding to the control signal of the pulse width of dutycycle between 25% and 50%.In this case, there are among pulse-width modulation control signal A, B, C, the D two zones of connecting simultaneously.That is to say, have two pulses overlapping areas in time.In addition, have at least one producing pulse among control signal A, B, C, the D all the time.As a result, output voltage 120 is discretely at V
InAnd 2V
InBetween change.As shown in Figure 4, frequency is four times of carrier frequency.
Fig. 6 shows the course of work that feedback controller 100 produces corresponding to the control signal of the pulse width of dutycycle between 50% and 75%.In this case, in any given moment, there are two or three to connect simultaneously among control signal A, B, C, the D.That is to say that two or three pulses are overlapping in the given arbitrarily moment.As a result, output voltage 130 is discretely at 2V
InAnd 3V
InBetween change.As shown in Figures 4 and 5, frequency is four times of carrier frequency.
Fig. 7 shows the course of work that feedback controller 100 produces corresponding to the control signal of the pulse width of dutycycle between 75% and 100%.In this case, in any given moment, there are three or four to connect simultaneously among control signal A, B, C, the D.That is to say that three or four pulses are overlapping in the given arbitrarily moment.As a result, output voltage 140 is discretely at 3V
InAnd 4V
InBetween change.As shown in Fig. 4-6, frequency is four times of carrier frequency.
As explanation among Fig. 5-7, gradient controller 22
1With gradient amplifier 20
1One of them advantage be (that is, to surpass maximum voltage 4V for higher required output voltage
In1/4th voltage), output voltage can not drop to zero volt.Equally, as explanation among Fig. 4-6, (that is, be lower than maximum voltage 4V for lower voltage
In3/4ths voltage), output voltage can not be elevated to maximum voltage 4V
InIn fact, for any given voltage, 1/4th of the just maximum voltage of instantaneous variation provides improved instantaneous voltage resolution like this.
At gradient amplifier 20
1In, high-speed field effect transistors 60,62 is never born above maximum voltage V
In, this maximum voltage V
InBe to be equivalent to 4V
InRated output voltage amplitude V
Rated1/4th.Therefore, the high-speed field effect transistors 60,62 that can utilize regulation to have the maximum working voltage that reduces constitutes regulator 50,52,54,56, and the wherein above-mentioned maximum working voltage that reduces surpasses V
InBut fully be lower than V
Rated
On the contrary, the igbt 72,74 of bipolar circuit 70 bears and offers gradient coil 16
1Full voltage amplitude V
RatedBut transistor 72,74 does not need high frequency to switch.Therefore, preferably, transistor 72,74 is selected in the high-power operation with the rate request that reduces.Particularly, the transistor 72,74 that can utilize regulation to have rated frequency constitutes bipolar circuit 70, and wherein this rated frequency is lower than the carrier frequency of pulse-width modulation control signal A, B, C, D basically.
Another advantage of utilizing bipolar circuit 70 separately rather than polarity being selected to be attached in the power governor is the complicacy that has reduced circuit.For example, illustrated half-bridge power regulator 50,52,54,56 is compared the element that comprises seldom with the similar circuit (as the full-bridge regulator) that comprises the polarity selection.
Although the gradient controller 22 with four regulator 50,52,54,56 has been described
1With gradient amplifier 20
1, but those skilled in the art can increase or reduce the voltage regulator level at an easy rate.For N regulator, the phase shifting value is preferably elected as 360 °/N.The output power frequency is N a times of carrier frequency.Voltage resolution is the rated voltage V by the quantity N division of voltage regulator level
Rated, that is to say that voltage resolution is V
Rated/ N.
If expand gradient amplifier 20 by comprising extra voltage regulator
1, each of wherein extra voltage regulator is scalable input voltage V all
In, then each extra voltage regulator has all increased and can be applied to gradient coil 16
1On maximum voltage.For example, each all regulates input voltage V
InSix exportable maximum voltages of voltage regulator be 6V
In, its voltage resolution is V
InBecause each of high-speed field effect transistors 60,62 all regulated maximum voltage V
InSo increasing more voltage regulator can not influence selection to high speed transistor 60,62.In fact, for the amplifier 20 under not being operated at a high speed
1Four transistors 70,72, may need it is made amendment, to adapt to the higher maximum voltage that when having increased more voltage regulator level, has been produced.
Alternative, when also obtaining rated voltage when the voltage of being regulated by each voltage regulator increases regulator stage by reducing.In this case, along with the increase voltage resolution of regulator stage has also increased, and high-speed field effect transistors 60,62 is handled lower maximum voltage.
The present invention has been described with reference to preferred embodiment.It is apparent that, reading and understanding on the basis of preceding detailed description and will make various modifications and variations.The present invention is exactly all such modifications and the variation that will plan to comprise in the scope that falls within appended claim and its equivalent.
Claims (24)
1. magnetic field gradient coils (16 that is used to drive MR imaging apparatus (10)
1) controlled source, this power supply comprises:
With a plurality of switch power regulators (50,52,54,56) of series connection form electrical connection, in order to provide power to this gradient coil (16
1); With
Control circuit (22
1), this control circuit provides the pulse-width modulation control signal (A, B, C, D) of phase shifting to give switch power regulator (50,52,54,56).
2. the power supply described in claim 1, wherein control circuit (22
1) comprising:
Phase-shift circuit (82,84,86), each phase-shift circuit are all introduced different selected phase shifts and are exchanged carrier signal (80) to limit the interchange carrier signal of phase shifting; With
Pulse-width modulation circuit (90,92,94,96), each pulse-width modulation circuit all receives the interchange carrier signal of one of them phase shifting, and produces and to have by the selected frequency of the interchange carrier signal of the phase shifting that is received and the train of impulses (A, B, C, D) of phase place.
3. the power supply described in claim 2, wherein control circuit (22
1) further comprise:
Feedback controller (100), itself and pulse-width modulation circuit (90,92,94,96) communicate with according to set point (102) with from magnetic field gradient coils (16
1) feedback signal come the pulse width of each pulse in the gating pulse string (A, B, C, D).
4. the power supply described in claim 1, wherein, control circuit (22
1) comprising:
Controller (100), this controller calculates the pulse width of pulse-width modulation control signal (A, B, C, D), and this pulse width that calculates control offers gradient coil (16
1) power.
5. the power supply described in claim 1, wherein, a plurality of switch power regulators (50,52,54,56) comprise N switch power regulator (50,52,54,56), and control circuit (22
1) the stagger pulse-width modulation control signal (A, B, C, D) of N phase shifting of 360 °/N of output phase.
6. the power supply described in claim 1 wherein, has four switch power regulators (50,52,54,56), and control circuit (22
1) output phase 90 ° the pulse-width modulation control signal (A, B, C, D) of four phase shiftings that staggers.
7. the power supply described in claim 1, wherein, the pulse-width modulation control signal of each phase shifting (A, B, C, D) has identical dutycycle.
8. the power supply described in claim 1, wherein, each switch power regulator (50,52,54,56) comprising:
The half-bridge amplifier.
9. the power supply described in claim 1, wherein, each switch power regulator (50,52,54,56) comprises high-speed field effect transistors (60,62).
10. the power supply described in claim 1, wherein, switch power regulator (50,52,54,56) add up to N, and each switch power regulator (50,52,54,56) all comprises:
Rated voltage is lower than V
RatedAnd be higher than V
RatedThe high-speed field effect transistors of/N (60,62), wherein V
RatedProvide to gradient coil (16
1) maximum voltage amplitude.
11. the power supply described in claim 1 further comprises:
Bipolar circuit (70), this bipolar circuit receives the power from the switch power regulator that is connected in series (50,52,54,56), and with selected polarity power is offered gradient coil (16
1).
12. the power supply described in claim 11, wherein, control circuit (22
1) comprising:
The timing circuit of the carrier signal that output phase staggers (80,82,84,86);
The pulsewidth circuit (100) of output pulse width parameter; With
Pulse width modulator (90,92,94,96), the pulse-width modulation control signal (A, B, C, D) of the carrier signal of the with good grounds phase shifting of its output device and definite phase place and the pulse width corresponding with the pulsewidth parameter.
13. the power supply described in claim 12, wherein, pulse width modulator (90,92,94,96) comprising:
A plurality of pulse width modulators (90,92,94,96), each all receives the carrier signal of one of them phase shifting and exports one of them pulse-width modulation control signal (A, B, C, D).
14. the power supply described in claim 12, wherein, pulsewidth circuit (100) is according to the gradient coil (16 that measures
1) running parameter calculate the pulsewidth parameter.
15. the power supply described in claim 11, wherein, bipolar circuit (70) comprising:
Full-bridge circuit.
16. the power supply described in claim 11, wherein, bipolar circuit (70) comprises igbt (72,74).
17. the power supply described in claim 11, wherein, bipolar circuit (70) comprising:
Rated frequency is lower than the transistor (72,74) of the frequency of pulse-width modulation control signal (A, B, C, D) basically.
18. one kind provides the magnetic field gradient coils (16 of controlled power to MR imaging apparatus (10)
1) method, this method comprises:
Produce the pulse-width modulation control signal (A, B, C, D) of phase shifting;
Produce the output of a plurality of switch powers, by changing each in these a plurality of switch powers outputs one of in the pulse-width modulation control signal (A, B, C, D) of phase shifting;
This switch power output of tandem compound; And
Provide the switch power of tandem compound to export to gradient coil (16
1).
19. the method described in claim 18, wherein, the generation of the pulse-width modulation control signal of phase shifting (A, B, C, D) comprising:
By selected phase shift carrier signal (80) is carried out phase shift;
Trigger electric pulse with selected pulse width according to carrier signal (80); With
Repeat this phase shift and trigger step in a plurality of phase shifts each.
20. the method described in claim 19, wherein, each in a plurality of phase shifts all is the integral multiple of basic phase shift.
21. the method described in claim 20, wherein, basic phase shift is 360 °/N, and wherein N is the sum of the pulse-width modulation control signal (A, B, C, D) of phase shifting.
22. the method described in claim 18 further comprises:
Select the dutycycle of the pulse-width modulation control signal (A, B, C, D) of phase shifting according to required magnetic field gradient.
23. the method described in claim 18 wherein, offers gradient coil (16 with the output of the switch power of tandem compound
1) step comprise:
With selected polarity the switch power output of tandem compound is offered gradient coil.
24. magnetic field gradient coils (16 that is used for controlled power is offered MR imaging apparatus (10)
1) equipment, this equipment comprises:
Be used to produce the device (22 of the pulse-width modulation control signal (A, B, C, D) of phase shifting
1);
Be used to produce the device (50,52,54,56) of a plurality of switch powers outputs, by changing each in these a plurality of switch powers outputs one of in the pulse-width modulation control signal (A, B, C, D) of phase shifting;
The device (S) that is used for this switch power output of tandem compound; With
Be used to provide the switch power of tandem compound to export to gradient coil (16
1) device (70).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44455803P | 2003-02-03 | 2003-02-03 | |
| US60/444,558 | 2003-02-03 |
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|---|---|
| CN1745315A true CN1745315A (en) | 2006-03-08 |
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ID=32850884
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200480003381 Pending CN1745315A (en) | 2003-02-03 | 2004-01-22 | MRI precision gradient amplifier with multiple output voltage levels |
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|---|---|
| EP (1) | EP1595159A1 (en) |
| JP (1) | JP2006516439A (en) |
| CN (1) | CN1745315A (en) |
| WO (1) | WO2004070411A1 (en) |
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Family Cites Families (4)
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| JP3557009B2 (en) * | 1995-08-09 | 2004-08-25 | 株式会社日立メディコ | Power supply device and magnetic resonance imaging apparatus using the same |
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| US6166602A (en) * | 1999-09-27 | 2000-12-26 | General Electric Company | High-efficiency switching power amplifier |
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2004
- 2004-01-22 EP EP04704295A patent/EP1595159A1/en not_active Withdrawn
- 2004-01-22 WO PCT/IB2004/000180 patent/WO2004070411A1/en active Application Filing
- 2004-01-22 CN CN 200480003381 patent/CN1745315A/en active Pending
- 2004-01-22 JP JP2006502365A patent/JP2006516439A/en not_active Withdrawn
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Also Published As
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|---|---|
| JP2006516439A (en) | 2006-07-06 |
| WO2004070411A1 (en) | 2004-08-19 |
| EP1595159A1 (en) | 2005-11-16 |
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