JPS61285518A - High frequency power unit for magnetic resonance imaging device - Google Patents
High frequency power unit for magnetic resonance imaging deviceInfo
- Publication number
- JPS61285518A JPS61285518A JP60127522A JP12752285A JPS61285518A JP S61285518 A JPS61285518 A JP S61285518A JP 60127522 A JP60127522 A JP 60127522A JP 12752285 A JP12752285 A JP 12752285A JP S61285518 A JPS61285518 A JP S61285518A
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- Prior art keywords
- power supply
- constant
- high frequency
- frequency power
- voltage
- Prior art date
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- Magnetic Resonance Imaging Apparatus (AREA)
- Continuous-Control Power Sources That Use Transistors (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の技術分野］
本発明は磁気共鳴（Ｍ Ｒ： Ｍ ａｇｎｅｔｉｃ Ｒ
ｅｓｏｎａ−ｎｃｅ、以下ＭＲと称する）現象を用いて
被検体のある断面における特定の原子核スピン密度の分
布をいわゆるコンピュータ断層法（ＣＴ ： Ｃｏｉｐ
ｕｔｅｄＴ ＯＩＩｌＯｇｒａｌ）ｈＶ ）によりＣＴ
像として画像化する磁気共鳴イメージング装Ｍ（以下Ｍ
ＲＩと称する）（１）ａｍｍ’Ｒ１１’ｌＡＭｃｌ１６
６ａ＞ｒｌｒ６° １［発明の技術的背景］
原子は原子核と軌道電子とで構成されている。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to magnetic resonance (MR) technology.
The distribution of a specific atomic nuclear spin density in a certain cross-section of an object is measured using the so-called computer tomography (CT: Coip) phenomenon.
CT by utedT
Magnetic resonance imaging device M (hereinafter referred to as M
(referred to as RI) (1) amm'R11'lAMcl16
6a>rlr6° 1 [Technical Background of the Invention] An atom is composed of an atomic nucleus and orbital electrons.
多くの原子核はそれぞれ固有なスピン（自転）を持つ。Many atomic nuclei each have their own unique spin (rotation).
原子核はまた電荷を持っているので、スピンはその回転
軸の回りの電流に相当し小さな磁場を発生する。原子核
の陽子と中性子のいずれかが奇数のもの（”Ｈ，”Ｐ、
１３Ｃ１など）はこの磁場による磁気モーメント（磁気
双極子）を持つ。Since the nucleus also has an electric charge, its spin corresponds to an electric current around its axis of rotation, which generates a small magnetic field. If either the protons or neutrons in the nucleus are an odd number (“H,” P,
13C1, etc.) have a magnetic moment (magnetic dipole) due to this magnetic field.
普通、スピンを持つ核の磁気モーメントは勝手な方向を
向いているが、静磁場中に置くと磁力線の方向に向く。Normally, the magnetic moment of a nucleus with spin points in an arbitrary direction, but when placed in a static magnetic field, it points in the direction of the magnetic field lines.
そして第４図（ｂ）に示すように磁力線の回りをちょう
どゴマの゛みそすり運動″のような歳差運動を始める。Then, as shown in Figure 4(b), it begins to precess around the lines of magnetic force, just like the ``sweeping motion'' of a sesame seed.
この運動は゛°プラーアの歳差運動″と呼ばれ、その周
期は原子核の種類と静磁場の強さによって決まっている
。This motion is called ``Praher's precession,'' and its period is determined by the type of atomic nucleus and the strength of the static magnetic field.
ここで磁気モーメントの台数和の体積あたりの値を磁化
Ｍと定義する。Here, the value of the sum of the number of magnetic moments per volume is defined as magnetization M.
この状態で、静磁場と垂直な面内に回転磁場を掛は周波
数を変化させる。すると回転磁場の周波数と歳差運動の
周波数が一致したとき、磁化Ｍは回転磁場のエネルギー
を吸収して第４図＜ａ ＞のように倒れてくる。いわゆ
る共鳴現象がおこる。In this state, a rotating magnetic field is applied in a plane perpendicular to the static magnetic field to change the frequency. Then, when the frequency of the rotating magnetic field and the frequency of the precession match, the magnetization M absorbs the energy of the rotating magnetic field and falls down as shown in Fig. 4<a>. A so-called resonance phenomenon occurs.
この現象を磁気共鳴という。This phenomenon is called magnetic resonance.
回転磁場を切ると磁化Ｍは吸収したエネルギーを放出し
て元の状態（Ｚ軸の方向の最初の位置）に戻る。このと
き、静磁場の方向に直交した方向に受信コイルを配置す
ると、磁化Ｍの歳差運動すなわち磁気双極子の回転によ
って受信コイルには電流が誘起され、磁化Ｍが元に戻っ
ていく過程で減衰する。これを自由誘導減衰（ＦＩＤ）
という。When the rotating magnetic field is turned off, the magnetization M releases the absorbed energy and returns to its original state (initial position in the Z-axis direction). At this time, if the receiving coil is placed in a direction perpendicular to the direction of the static magnetic field, a current is induced in the receiving coil by the precession of the magnetization M, that is, the rotation of the magnetic dipole, and in the process of the magnetization M returning to its original state. Attenuate. This is called free induction decay (FID)
That's what it means.
ＭＲ映像法では第５図（ａ ”）のように回転磁場をパ
ルス状に与えることが多い。今、回転座標系の軸をｘ
ｌ 、 ｙ ′、 ｚ ｌ とすると第４図（ｃ ）に
示すように磁化Ｍを２′軸に垂直なｘ ′、 ｙ Ｔ平
面まで倒すのに必要な回転磁場のエネルギーを９０°パ
ルス、ｚ′軸の負方向まで倒すのに必要な回転磁場のエ
ネルギーを１８０°パルスと呼ぶ。In MR imaging, a rotating magnetic field is often applied in the form of a pulse as shown in Figure 5 (a'').Now, the axis of the rotating coordinate system is x.
l , y ', z l , the energy of the rotating magnetic field required to tilt the magnetization M to the x', y T plane perpendicular to the 2' axis as shown in Figure 4(c) is given by a 90° pulse, z The energy of the rotating magnetic field required to tilt the axis in the negative direction is called a 180° pulse.
この様にＭＲＩでは、静磁場とは垂直な平面にパルス状
のラーモア周波数に一致する回転磁場をかけることが重
要である。In this manner, in MRI, it is important to apply a rotating magnetic field that matches the pulsed Larmor frequency in a plane perpendicular to the static magnetic field.
この回転磁場をかけるには高周波の電磁波を発生すれば
よい。すなわち、静磁場の方向と直交した方向に送信コ
イルを配し、この送信コイルに高周波電源装置より高周
波電力を供給すれば電磁波が発生する。To apply this rotating magnetic field, it is sufficient to generate high-frequency electromagnetic waves. That is, if a transmitting coil is arranged in a direction perpendicular to the direction of the static magnetic field and high-frequency power is supplied to the transmitting coil from a high-frequency power supply, electromagnetic waves are generated.
先に述べたように磁化Ｍはラーモア周波数に一致する回
転磁場のエネルギーを吸収して共鳴する。As mentioned above, the magnetization M absorbs the energy of the rotating magnetic field that matches the Larmor frequency and resonates.
このエネルギーは送信出力電力と時間の積である。This energy is the product of transmitted output power and time.
時間の制御が十分な精度でおこなえるものとすると、高
周波電源装置の送信出力電力の変動によって回転磁場の
安定性が決まる。回転磁場の変動は受信コイルに誘起さ
れるＦＩＤ信号の変動となって表われる。したがって、
ＭＲＩにおいて高周波電源装置の送信出力電力を安定化
することは精度のよい測定をする上で非常に重要なこと
である。Assuming that time control can be performed with sufficient precision, the stability of the rotating magnetic field is determined by fluctuations in the transmission output power of the high-frequency power supply. Fluctuations in the rotating magnetic field appear as fluctuations in the FID signal induced in the receiving coil. therefore,
In MRI, stabilizing the transmission output power of a high frequency power supply is very important for accurate measurement.
高周波電源装置の送信出力電力は人体の表皮効果の影響
で周波数によって異なるが、概ね数百Ｗ〜数ｋＷの範囲
である。これだけの電力を出力するためには高周波電源
装置の効率を考えると１．５〜２倍程度の入力電力が必
要である。しかし第５図（ａ ）のよに送信出力はパル
ス状であるため平均した入力電力は１／Ｄｌｊｔ’／程
度でよい（Ｄ ｕｔｙはパルスが出ている時間とパルス
の周期の比）。The transmission output power of a high-frequency power supply device varies depending on the frequency due to the skin effect of the human body, but is generally in the range of several hundred W to several kW. In order to output this much power, an input power of about 1.5 to 2 times is required, considering the efficiency of the high frequency power supply device. However, as shown in FIG. 5(a), since the transmission output is in the form of pulses, the average input power may be about 1/Dljt'/ (Duty is the ratio of the pulse period to the pulse period).
このため第６図のように定電圧・定電流電源１の出力端
に人寄」コンデンサ２を接続し、九周波を出力しない時
間に充電しておき、高周波を出力する時にはｒ ３．
Ｓ ４で模式的に表現した高周波電力増幅器５へ一気に
放電する回路が考えられる。For this reason, as shown in Fig. 6, a capacitor 2 is connected to the output terminal of the constant voltage/constant current power supply 1, and is charged when the nine-frequency wave is not output, and when the high-frequency wave is output.
A circuit that discharges all at once to the high frequency power amplifier 5, schematically represented by S4, can be considered.
このときの高周波電力増幅器５の電ａ電圧は第７図＜ａ
＞の様な高周波出力とすれば第７図（ｂ ）のように
変動する。At this time, the voltage a of the high frequency power amplifier 5 is shown in FIG.
If the high frequency output is as shown in FIG. 7(b), it will fluctuate as shown in FIG.
高周波電力増幅器の電源電圧と出力電力との間には回路
形式によって異なるが、ある一定の関係がある。例えば
シングルエンドブシュプルといわれる様な回路（第３図
を参照）では
ｖ［）Ｏ：電源電圧
ＶＳａｔ：電力素子の飽和電圧
ＲＬ：負荷抵抗
ＰＯ：出力電力
である。したがって第７図（ｂ）の様に電源電圧が変動
すると、出力電力が変動し、先に述べた様に精度のよい
測定ができなくなる。そこで、この電源電圧の変動を小
さく抑えるためには時定数Ｃｏ−ｒを大きくする必要が
ある。ｒは高周波電力増幅器５の内部抵抗によって決ま
る値なので、時定数ＣＯ・ｒを大きくするためにはコン
デンサ２の容ＩＣｏを大きくするしかない。Although it differs depending on the circuit type, there is a certain relationship between the power supply voltage and output power of a high-frequency power amplifier. For example, in a circuit called a single-end bush-pull (see FIG. 3), v[)O: power supply voltage VSat: saturation voltage RL of the power element: load resistance PO: output power. Therefore, when the power supply voltage fluctuates as shown in FIG. 7(b), the output power fluctuates, making it impossible to perform accurate measurements as described above. Therefore, in order to suppress this fluctuation in the power supply voltage, it is necessary to increase the time constant Cor. Since r is a value determined by the internal resistance of the high frequency power amplifier 5, the only way to increase the time constant CO·r is to increase the capacitance ICo of the capacitor 2.
［、背景技術の問題点１ 第８図に定電圧・定電流電源１の一例を示す。[, Problem 1 of background technology FIG. 8 shows an example of the constant voltage/constant current power supply 1.
今、大容量コンデンサ２は完全に充電されているとして
、保守・点検などのために電源スイッチＳＷを切ったと
する。大容量コンデンサ２に充電された電荷は抵抗Ｒ２
，抵抗Ｒ３を介して放電することしかできない。一般に
抵抗Ｒ２、抵抗Ｒ３は大きな値を持っているため、放電
する時定数はＣＯ・（Ｒ２＋Ｒ３）となり長くなる。こ
の様な状態で保安員が保守点検・調整をおこなうのは感
電のおそれがあって非常に危険である。Assume that the large-capacity capacitor 2 is now fully charged and that the power switch SW is turned off for maintenance or inspection. The electric charge charged in the large capacity capacitor 2 is the resistance R2
, can only be discharged through resistor R3. Since the resistors R2 and R3 generally have large values, the time constant for discharging becomes CO·(R2+R3) and becomes long. It is extremely dangerous for security personnel to carry out maintenance inspections and adjustments under such conditions as there is a risk of electric shock.
そこで第９図の様に大容量コンデンサ２の両端子に抵抗
Ｒ２，抵抗Ｒヨの合成値（Ｒ２＋Ｒ３）より抵抗値の小
さい抵抗６を接ぐことによって時定数Ｃｏ ＲＯで放電
しようとするものが考えられる。しかし、この回路では
抵抗６で消費される電力を余分に供給する必要があり、
時定数Ｃｏ Ｒ。Therefore, an idea is to connect a resistor 6 whose resistance value is smaller than the combined value (R2 + R3) of resistors R2 and R to both terminals of the large capacity capacitor 2 as shown in Figure 9 to discharge the capacitor with a time constant Co RO. It will be done. However, in this circuit, it is necessary to supply extra power consumed by resistor 6,
Time constant Co R.
を小さくしようとすれば効率が悪くなる。If you try to make it smaller, the efficiency will decrease.
［発明の目的］ 本発明は、この様な状況に鑑みてなされたちのである。[Purpose of the invention] The present invention has been made in view of this situation.
すなわちＭＲＩの高周波電源において、高周波電力増幅
器の電源である定電圧・定電流電源の負荷に接続した出
力安定化用大容量コンデンサを電源スイッチが切られた
ときにはすみやかにとしている。That is, in the high frequency power supply for MRI, a large capacity capacitor for output stabilization connected to the load of the constant voltage/constant current power supply, which is the power supply for the high frequency power amplifier, is quickly turned off when the power switch is turned off.
［発明の概要］
かかる目的を達成するために、磁気共鳴イメージング装
置の轟周波電源装置においては、外部からバイアス電圧
が自由に制御できる高周波電力増幅器と、この高周波電
力増幅器へ直流電力を供給する定電圧・定電流電源と、
この定電圧・定電流電源の出力端子間に接続した天啓」
コンデンサと、電源スイッチを切った後定電圧・定Ｎ流
電源をただちに切る信号及び上記高周波電力増幅器の電
力素子のバイアス電圧を制御して上記大容量コンデンサ
が完全に放電するまでの時間その電力素子がオン状態と
なっていることができる信号を出力する電源シーケンサ
とで構成され、上記電源スイッチを切るとともに上記定
電圧・定電流電源の出力端子間に接続された大容量コン
デンサをすみやかに放電するようにしたことを特徴とす
る。[Summary of the Invention] In order to achieve the above object, a roaring frequency power supply device for a magnetic resonance imaging apparatus includes a high frequency power amplifier whose bias voltage can be controlled freely from the outside, and a constant power amplifier that supplies DC power to the high frequency power amplifier. Voltage/constant current power supply,
A revelation connected between the output terminals of this constant voltage/constant current power supply.
The capacitor, a signal to immediately turn off the constant voltage/constant N current power supply after the power switch is turned off, and the bias voltage of the power element of the high frequency power amplifier are controlled to control the time until the large capacity capacitor is completely discharged from that power element. and a power supply sequencer that outputs a signal indicating that the power source is in the on state, which turns off the power switch and promptly discharges the large capacitor connected between the output terminals of the constant voltage/constant current power source. It is characterized by the following.
一実施例を第６図乃至第９図と同一部分には同一符号を
付した第１図乃至第３図を参照して説明する。One embodiment will be described with reference to FIGS. 1 to 3, in which the same parts as in FIGS. 6 to 9 are given the same reference numerals.
第１図は本発明の一実施例である。すなわち、電源シー
ケンサ−７が電源入／切信号８によって″切”と指示さ
れたとき、出力リモートコントロール信号９によって定
電圧・定電流電源１の電源スイッチＳＷをすみやかに切
る。又、大官」コンデンサ２が完全に放電する時間、タ
イマー信号を出し続けて、その間、後述する高周波電力
増幅器の電力素子４′のバイアスを高くして高周波電力
増幅器の内部抵抗３と大容量コンデンサ２からなる時定
数ＣＯ・ｒで放電する。ここで、数ｋＷの電力を出力す
るためには高周波電力増幅器は、数台〜数十台並列に設
置されるので内部抵抗３は非常に小さい値となり、又、
放電時に流れる放電電流も各素子に分配されるので電力
素子４′が破壊される心配はない。FIG. 1 shows an embodiment of the present invention. That is, when the power supply sequencer 7 is instructed to "off" by the power on/off signal 8, the power switch SW of the constant voltage/constant current power supply 1 is immediately turned off by the output remote control signal 9. Also, the timer signal is continued to be output until the capacitor 2 is completely discharged, and during that time, the bias of the power element 4' of the high-frequency power amplifier, which will be described later, is increased to reduce the internal resistance 3 and the large-capacity capacitor of the high-frequency power amplifier. Discharge occurs with a time constant CO·r consisting of 2. Here, in order to output power of several kW, several to several dozen high-frequency power amplifiers are installed in parallel, so the internal resistance 3 has a very small value.
Since the discharge current that flows during discharge is also distributed to each element, there is no fear that the power element 4' will be destroyed.
電源シーケンサ−の一実施例を第２図に示す。An embodiment of the power supply sequencer is shown in FIG.
今、電源入／切信号８により応動する電源スイッチ１１
．１２．１３（連動）が入”→゛切”になりた瞬間であ
るとする。定電圧・定電流電源１のリモートコントロー
ル用スイッチ１２はショートされ、出力リモートコント
ロール信号９が定電圧・定電流電源１へ送られる。定電
圧・定電流電源１は出力リモートコントロール信号９が
ショートすると電源スイッチをすみヤかに切る。同時に
タイマースタートスイッチ１３がＬ ”レベルになりタ
イマー１６がスタートする。このときタイマ信号７０は
゛Ｌ″レベルとなり高周波電力増幅器へ送られる。バイ
アスｌ ｔ’！ １７は第１のバイアスリモートコント
ロールスイッチ１１がショートしても、第２のバイアス
リモートっント。−ル ：′と
スイッチ１８がオーブンのためバイアス電圧＋８１を出
力し続ける。ある時間経過するとタイマー１６からタイ
プアップ信号が発生し、ＮＯＲ素子１５を介してトラン
ジスタ１４を“ＯＦＦ”にする。これによって第２のバ
イアスリモートコントロールスイッチ１８がショートし
、バイアス電源スイッチが切れる。又、これと同時にタ
イマ信号１０も８１ルベルの状態となる。Now, the power switch 11 responds to the power on/off signal 8
．． 12. It is assumed that the moment when 13 (interlocking) changes from "on" to "off". The remote control switch 12 of the constant voltage/constant current power supply 1 is short-circuited, and the output remote control signal 9 is sent to the constant voltage/constant current power supply 1. The constant voltage/constant current power supply 1 immediately turns off the power switch when the output remote control signal 9 is short-circuited. At the same time, the timer start switch 13 goes low and the timer 16 starts. At this time, the timer signal 70 goes low and is sent to the high frequency power amplifier. Bias l t'! 17 is a second bias remote control switch even if the first bias remote control switch 11 is short-circuited. -R:' and switch 18 continue to output the bias voltage +81 for the oven. When a certain period of time has elapsed, a type-up signal is generated from the timer 16, and the transistor 14 is turned off via the NOR element 15. This short-circuits the second bias remote control switch 18 and turns off the bias power switch. At the same time, the timer signal 10 also becomes 81 lvl.
第３図は高周波電力増幅器モジュールの一実施例である
。バイアスコントロール信号１９は高周波電力を出力す
るときは電力素子２０．２１のバイアス電圧を制御して
動作点をＡＢ級にするためのものである。すなわち、バ
イアスコントロール信号１９が°゛Ｌ゛°Ｌ゛°レベル
トランジスタ２２．２３は“ＯＦ Ｆ ”となるためコ
レクターの電圧は高くなり電力力素子２０．２１のバイ
アス電圧も高くなる。これによって動作点はＡＢ級にな
る。バイアスコントロール信号１９がＨ”になったとき
にはトランジスタ２２．２３が“ＯＮ′′になり、コレ
クター電圧は低くなる。このため電力素子２０．２１の
バイアス電圧は低くなり動作点は０級になる。Ｃ級動作
させることによってノイズを増幅しないようにしている
。FIG. 3 shows an embodiment of a high frequency power amplifier module. The bias control signal 19 is used to control the bias voltage of the power elements 20 and 21 to set the operating point to class AB when high frequency power is output. That is, since the bias control signal 19 is at the °L level, the transistors 22 and 23 are set to "OFF", so the voltage of the collector becomes high and the bias voltage of the power element 20 and 21 also becomes high. As a result, the operating point becomes class AB. When the bias control signal 19 becomes H, the transistors 22 and 23 become "ON'', and the collector voltage becomes low. Therefore, the bias voltage of the power elements 20 and 21 becomes low and the operating point becomes class 0. Class C operation prevents noise from being amplified.
第２図において電源スイッチ１３によって大容量コンデ
ンサが完全に放電される時間、タイマ信号１０が゛Ｌ′
ルベルになっている。タイマ信号１０が°Ｌ”レベルに
なると、トランジスタ２２゜２３は“ＯＦＦ”となり電
力素子２０．２１のバイアス電圧は高くなる。電力素子
２０．２１はタイマ信号１０が“ＨＩＴレベルになるま
で゛” ＯＮ ”状態となる。すなわち、第１図のスイ
ッチＳＷがＯＮになっている状態である。In FIG. 2, the timer signal 10 is set to ``L'' during the time when the large capacity capacitor is completely discharged by the power switch 13.
It has become a rubel. When the timer signal 10 reaches the "°L" level, the transistors 22 and 23 turn "OFF" and the bias voltage of the power elements 20 and 21 becomes high. It becomes “ON” state. That is, the switch SW in FIG. 1 is in the ON state.
上記の様に実施例によれば、電源シーケンサ７により電
源スイッチＳＷを切ると同時にすみやかに大容量コンデ
ンサ２の放電がおこなわれ、保守点検時に感電すること
なく安心して作業することができるようになる。As described above, according to the embodiment, the large-capacity capacitor 2 is immediately discharged by the power supply sequencer 7 at the same time as the power switch SW is turned off, making it possible to work with peace of mind without getting an electric shock during maintenance and inspection. .
［発明の効果］
以上述べたように本発明によれば、外部からバイアス電
圧が自由に制御できる高周波電力増幅器と、この高周波
電力増幅器へ直流電力を供給する定電圧・定電流電源と
、この定電圧・定電流電源の出力端子間に接続した大容
量コンデンサと、電源スイッチを切った後定電圧・定電
流電源をただちに切る信号及び上記高周波電力増幅器の
電力素子のバイアス電圧を制御して上記大容量コンデン
サが完全に放電するまでの時間その電力素子がオン状態
になっていることができる信号を出力する電源シーケン
サとで構成され、上記電源スイッチを切るとともに上記
定電圧・定電流％１ｌｌｉの出力端子間に接続された大
容量コンデンサをすみやかに供できるものである。[Effects of the Invention] As described above, according to the present invention, a high frequency power amplifier whose bias voltage can be controlled freely from the outside, a constant voltage/constant current power source that supplies DC power to the high frequency power amplifier, and a constant voltage/constant current power source that supplies DC power to the high frequency power amplifier, The high-capacity capacitor connected between the output terminals of the voltage/constant current power supply, the signal to immediately turn off the constant voltage/constant current power supply after the power switch is turned off, and the bias voltage of the power element of the high frequency power amplifier are controlled to It consists of a power supply sequencer that outputs a signal that allows the power element to remain in the on state for a period of time until the capacitor is completely discharged, and when the power switch is turned off, the output of the constant voltage and constant current is output. A large capacity capacitor connected between the terminals can be quickly provided.
第１図は本発明の一実施例を示す回路図、第２図は同実
施例における電源シーケンサを示す詳細回路図、第３図
は同実施例における高周波電力増幅器を示す詳ｍ回路図
、第４図及び第５図はＭＲ現象の原理を説明する図、第
６図及び第７図は定電圧・定電流電源と高周波電力増幅
器と大容量コンデンサとの関係を示した図、第８図及び
第９図は従来例を示す回路図である。
１・・・定電圧・定電流ＭＨ，２・・・大容量コンデン
サ、３・・・高周波電力増幅器の内部抵抗、４．４′・
・・電力素子のスイッチ、５・・・高周波電力増幅器、
７・・・電源シーケンサ。
出願人代理人 弁理士 鈴 江 武 彦第４図
第５ｖ！ＪFIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a detailed circuit diagram showing a power supply sequencer in the same embodiment, FIG. 3 is a detailed circuit diagram showing a high frequency power amplifier in the same embodiment, and FIG. Figures 4 and 5 are diagrams explaining the principle of the MR phenomenon, Figures 6 and 7 are diagrams showing the relationship between a constant voltage/constant current power supply, a high frequency power amplifier, and a large capacity capacitor, and Figures 8 and FIG. 9 is a circuit diagram showing a conventional example. 1... Constant voltage/constant current MH, 2... Large capacity capacitor, 3... Internal resistance of high frequency power amplifier, 4.4'.
...Power element switch, 5...High frequency power amplifier,
7...Power supply sequencer. Applicant's agent Patent attorney Takehiko Suzue Figure 4, Figure 5v! J
Claims (1)
外部からバイアス電圧が自由に制御できる高周波電力増
幅器と、この高周波電力増幅器へ直流電力を供給する定
電圧・定電流電源と、この定電圧・定電流電源の出力端
子間に接続した大容量コンデンサと、電源スイッチを切
った後定電圧・定電流電源をただちに切る信号及び上記
高周波電力増幅器の電力素子のバイアス電圧を制御して
上記大容量コンデンサが完全に放電するまでの時間その
電力素子がオン状態となっていることができる信号を出
力する電源シーケンサとで構成され、上記電源スイッチ
を切るとともに上記定電圧・定電流電源の出力端子間に
接続された大容量コンデンサをすみやかに放電するよう
にした磁気共鳴イメージング装置の高周波電源装置。In the high frequency power supply device of the magnetic resonance imaging device,
A high-frequency power amplifier whose bias voltage can be controlled freely from the outside, a constant-voltage/constant-current power supply that supplies DC power to this high-frequency power amplifier, and a large-capacity capacitor connected between the output terminals of this constant-voltage/constant-current power supply. , a signal that immediately turns off the constant voltage/constant current power supply after the power switch is turned off, and a bias voltage of the power element of the high frequency power amplifier is controlled so that the power element remains on for a period of time until the large capacity capacitor is completely discharged. and a power supply sequencer that outputs a signal that can be set to 0. When the power switch is turned off, the large-capacity capacitor connected between the output terminals of the constant voltage/constant current power supply is immediately discharged. High frequency power supply for magnetic resonance imaging equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60127522A JPS61285518A (en) | 1985-06-12 | 1985-06-12 | High frequency power unit for magnetic resonance imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60127522A JPS61285518A (en) | 1985-06-12 | 1985-06-12 | High frequency power unit for magnetic resonance imaging device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61285518A true JPS61285518A (en) | 1986-12-16 |
Family
ID=14962096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60127522A Pending JPS61285518A (en) | 1985-06-12 | 1985-06-12 | High frequency power unit for magnetic resonance imaging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61285518A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63214249A (en) * | 1987-03-04 | 1988-09-06 | 株式会社日立メディコ | Power source apparatus for nuclear magnetic resonance imaging apparatus |
| WO2014038422A1 (en) * | 2012-09-10 | 2014-03-13 | 株式会社東芝 | Magnetic resonance imaging equipment, and power control method for magnetic resonance imaging equipment |
| US9989602B2 (en) | 2012-09-10 | 2018-06-05 | Toshiba Medical Systems Corporation | Magnetic resonance imaging apparatus and a power control method of a magnetic resonance imaging apparatus |
| US10048337B2 (en) | 2012-09-10 | 2018-08-14 | Toshiba Medical Systems Corporation | Image diagnosis apparatus and power control method of an image diagnosis apparatus |
-
1985
- 1985-06-12 JP JP60127522A patent/JPS61285518A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63214249A (en) * | 1987-03-04 | 1988-09-06 | 株式会社日立メディコ | Power source apparatus for nuclear magnetic resonance imaging apparatus |
| JPH0377739B2 (en) * | 1987-03-04 | 1991-12-11 | Hitachi Medical Corp | |
| WO2014038422A1 (en) * | 2012-09-10 | 2014-03-13 | 株式会社東芝 | Magnetic resonance imaging equipment, and power control method for magnetic resonance imaging equipment |
| JP2014064898A (en) * | 2012-09-10 | 2014-04-17 | Toshiba Corp | Magnetic resonance imaging apparatus, and method for controlling power of magnetic resonance imaging apparatus |
| CN103796583A (en) * | 2012-09-10 | 2014-05-14 | 株式会社东芝 | Magnetic resonance imaging equipment, and power control method for magnetic resonance imaging equipment |
| CN103796583B (en) * | 2012-09-10 | 2017-03-01 | 东芝医疗***株式会社 | MR imaging apparatus and the electrical control method of MR imaging apparatus |
| US9989602B2 (en) | 2012-09-10 | 2018-06-05 | Toshiba Medical Systems Corporation | Magnetic resonance imaging apparatus and a power control method of a magnetic resonance imaging apparatus |
| US10048337B2 (en) | 2012-09-10 | 2018-08-14 | Toshiba Medical Systems Corporation | Image diagnosis apparatus and power control method of an image diagnosis apparatus |
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