公开(公告)号：US5916162A

公开(公告)日：1999-06-29

申请号：US914595

申请日：1997-08-18

申请人： Jeroen Snelten ,  Hans H. Tuithof

发明人： Jeroen Snelten ,  Hans H. Tuithof

IPC分类号： G01R33/20 ,  A61B5/055 ,  A61M25/00 ,  G01R33/28 ,  G01R33/36 ,  G01R33/48

CPC分类号： G01R33/285

摘要： An invasive device which is intended to cooperate with a magnetic resonance imaging apparatus is provided with an RF coil which is situated near a distal part of the invasive device. The RF coil is used so as to visualize the position of a distal end of the invasive device, introduced into an object, in an image of the object. Current induced by an RF field to be generated by the magnetic resonance imaging apparatus develops heat in the electric connection between the RF coil and a control unit, which may be annoying to a patient. In order to counteract the development of heat in the invasive device, the invasive device is provided with a hollow carrier. The electric connection extends through said carrier which is provided with an electrically conductive shield with an additional resistance.

摘要翻译： 旨在与磁共振成像装置配合的侵入性装置设置有位于侵入性装置的远端附近的RF线圈。 RF线圈用于将被引入到对象中的侵入性设备的远端的位置可视化在对象的图像中。 由磁共振成像装置产生的RF场引起的电流在RF线圈和控制单元之间的电连接中产生热量，这可能对患者造成烦恼。 为了抵抗侵入性装置中的热量的发展，侵入性装置设置有空心载体。 电连接延伸穿过所述载体，其具有带有附加电阻的导电屏蔽。

公开(公告)号：US09155138B2

公开(公告)日：2015-10-06

申请号：US13380587

申请日：2010-06-22

申请人： Jeroen Snelten

发明人： Jeroen Snelten

IPC分类号： H05B33/08 ,  H05B41/392

CPC分类号： H05B33/0815 ,  H05B41/3924 ,  Y02B20/347 ,  Y10T307/50

摘要： A current correction circuit (200) has an input (201) and includes: a first controllable current source (220) having an input connected to the circuit input for drawing a first current (I 220) from the circuit input; a differentiator (210) having an input coupled to the circuit input and having an output coupled to the first current source; and/or a second controllable current source (240) having an input connected to the circuit input for drawing a second current (I 240) from the circuit input; a voltage comparator (230) having a first input coupled to the circuit input (201), having a second input coupled to receive a reference signal (Vref), and having an output coupled to the second current source. The circuit is responsive to voltage changes by drawing first current pulses (221) from the circuit input, and/or to low voltages by drawing second current pulses (241) from the circuit input.

摘要翻译： 电流校正电路（200）具有输入（201），包括：第一可控电流源（220），其具有连接到电路输入的输入端，用于从电路输入端抽出第一电流（I 220） 微分器（210）具有耦合到电路输入并具有耦合到第一电流源的输出的输入; 和/或第二可控电流源（240），其具有连接到所述电路输入端的输入端，用于从所述电路输入端抽出第二电流（I 240） 电压比较器（230）具有耦合到电路输入（201）的第一输入，具有耦合以接收参考信号（Vref）的第二输入，以及耦合到第二电流源的输出。 电路通过从电路输入引出第一电流脉冲（221）和/或通过从电路输入引出第二电流脉冲（241）来响应于电压变化。

公开(公告)号：US08836225B2

公开(公告)日：2014-09-16

申请号：US13497533

申请日：2010-09-21

申请人： Jeroen Snelten ,  Geert Willem Van Der Veen

发明人： Jeroen Snelten ,  Geert Willem Van Der Veen

IPC分类号： H05B37/02 ,  H05B33/08

CPC分类号： H05B33/0815 ,  H05B33/0818 ,  Y02B20/346 ,  Y02B20/348

摘要： A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

摘要翻译： 可调光LED驱动器电路包括耦合到输出电路的谐振DC-DC转换器。 该转换器包括耦合到谐振电路的半桥或全桥开关电路。 谐振电路的输出被整流并馈送到输出电路。 输出电路可以包括用于切换LED单元的至少一个LED串联或分流开关。 控制电路以可变的开关频率来控制开关电路的开关。 控制电路还被配置为控制用于对转换器进行幅度调制的开关电路，并且以低于开关频率的第一脉冲宽度调制频率对转换器进行脉宽调制。 控制电路还可以被配置为在低于开关频率的第二脉冲宽度调制频率下控制LED开关的切换。

公开(公告)号：US20120181940A1

公开(公告)日：2012-07-19

申请号：US13497533

申请日：2010-09-21

申请人： Jeroen Snelten ,  Geert Willem Van Der Veen

发明人： Jeroen Snelten ,  Geert Willem Van Der Veen

IPC分类号： H05B37/02

CPC分类号： H05B33/0815 ,  H05B33/0818 ,  Y02B20/346 ,  Y02B20/348

摘要： A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

摘要翻译： 可调光LED驱动器电路包括耦合到输出电路的谐振DC-DC转换器。 该转换器包括耦合到谐振电路的半桥或全桥开关电路。 谐振电路的输出被整流并馈送到输出电路。 输出电路可以包括用于切换LED单元的至少一个LED串联或分流开关。 控制电路以可变的开关频率来控制开关电路的开关。 控制电路还被配置为控制用于对转换器进行幅度调制的开关电路，并且以低于开关频率的第一脉冲宽度调制频率对转换器进行脉宽调制。 控制电路还可以被配置为在低于开关频率的第二脉冲宽度调制频率下控制LED开关的切换。

公开(公告)号：US20120112657A1

公开(公告)日：2012-05-10

申请号：US13381980

申请日：2010-06-29

申请人： Geert Willem Van Der Veen ,  Jeroen Snelten

发明人： Geert Willem Van Der Veen ,  Jeroen Snelten

IPC分类号： H05B37/02 ,  H02J1/00 ,  H02M3/335

CPC分类号： H02M3/335 ,  H02M1/4225 ,  H02M2001/007 ,  H05B33/0815 ,  Y02B70/126 ,  Y10T307/25

摘要： A power supply circuit has an LLC converter stage for converting a DC voltage input into a DC voltage output, and at least one hysteretic converter stage. Each hysteretic converter stage has a DC voltage input coupled to the DC voltage output of the LLC converter stage, and a DC current output. The LLC converter stage lacks a feedback control, and is operated at its load independent point. A ripple on the DC voltage output of the LLC converter does not affect the output current of the hysteretic converter stage. The stable DC current output of the hysteretic converter stage is coupled to a load having one or more LED strings.

摘要翻译： 电源电路具有用于将DC电压输入转换为DC电压输出的LLC转换器级和至少一个迟滞转换级。 每个迟滞转换器级具有耦合到LLC转换器级的DC电压输出的直流电压输入和直流电流输出。 LLC转换器级缺乏反馈控制，并且在其负载独立点运行。 LLC转换器的直流电压输出上的纹波不影响滞后转换器级的输出电流。 迟滞转换器级的稳定DC电流输出耦合到具有一个或多个LED串的负载。

公开(公告)号：US08115536B2

公开(公告)日：2012-02-14

申请号：US12596866

申请日：2008-04-21

申请人： Jeroen Snelten

发明人： Jeroen Snelten

IPC分类号： G05F1/10

CPC分类号： H05B33/0818 ,  H02M3/1563 ,  Y02B20/346

摘要： A self-oscillating switch circuit for amplitude modulation dimming for dimming a LED load. The self-oscillating switch circuit comprises a high-power input terminal (S2) for supplying a first power to the load and a low-power input terminal (S1) for supplying a second power to the load. The switch circuit further comprises a power switch semi-conductor device (Q1) configured for controlling a load current from at least one of the high-power input terminal (S2) and the low-power input terminal (S1) to the output terminal. A control semi-conductor device (Q2) is configured to control the power switch semi-conductor device (Q1) in response to a sensing voltage. The sensing circuit comprises a first sensing resistor (R1A) and a second sensing resistor (R1B) for generating the sensing voltage such that a load current has a predetermined first peak current level corresponding to the first power, when power is supplied to the high-power input terminal, and the load current has a predetermined second peak current level corresponding to the second power when power is supplied to the low-power input terminal.

摘要翻译： 一种用于调光LED负载的调幅调光的自振荡开关电路。 自振荡开关电路包括用于向负载提供第一功率的大功率输入端（S2）和用于向负载提供第二功率的低功率输入端（S1）。 开关电路还包括电源开关半导体器件（Q1），其被配置为用于控制从大功率输入端子（S2）和低功率输入端子（S1）中的至少一个到输出端子的负载电流。 控制半导体器件（Q2）被配置为响应感测电压来控制功率开关半导体器件（Q1）。 感测电路包括用于产生感测电压的第一感测电阻器（R1A）和第二感测电阻器（R1B），使得负载电流具有对应于第一功率的预定的第一峰值电流电平， 电力输入端子，并且当向低功率输入端子供电时，负载电流具有对应于第二功率的预定的第二峰值电流电平。

公开(公告)号：US20100117656A1

公开(公告)日：2010-05-13

申请号：US12596863

申请日：2008-04-23

申请人： Jeroen Snelten

发明人： Jeroen Snelten

IPC分类号： G01R31/00

CPC分类号： H05B33/0893 ,  H05B33/0887

摘要： In order to detect a defective light source, such as a LED coupled to a DC-DC converter circuit for receiving a power signal, an outage detection circuit comprises a top voltage detector coupled to the LED for detecting a voltage across the LED. The top voltage detector has an top voltage terminal for supplying a top voltage signal. The detection circuit further comprises a differential amplifier coupled to the top voltage terminal for receiving the top voltage signal as a first input signal and coupled to a reference voltage terminal. The reference voltage terminal is configured to supply a reference voltage as a second input signal. The differential amplifier comprises an output terminal for supplying an outage detection signal.

摘要翻译： 为了检测诸如耦合到用于接收功率信号的DC-DC转换器电路的LED的有缺陷的光源，中断检测电路包括耦合到LED的顶部电压检测器，用于检测LED两端的电压。 顶部电压检测器具有用于提供顶部电压信号的顶部电压端子。 检测电路还包括耦合到顶部电压端子的差分放大器，用于接收顶部电压信号作为第一输入信号并耦合到参考电压端子。 参考电压端子被配置为提供参考电压作为第二输入信号。 差分放大器包括用于提供中断检测信号的输出端子。

公开(公告)号：US20100045204A1

公开(公告)日：2010-02-25

申请号：US12596866

申请日：2008-04-21

申请人： Jeroen Snelten

发明人： Jeroen Snelten

IPC分类号： H05B41/36

CPC分类号： H05B33/0818 ,  H02M3/1563 ,  Y02B20/346

摘要： A self-oscillating switch circuit for use in a switching DC-DC converter that is enabled to use amplitude modulation dimming for dimming a load such as a LED is provided. The dimming may be used to provide two or more distinct light output levels, which may be used in automotive combined tail and break lighting, for example. The self-oscillating switch circuit comprises an output terminal (Ton P1), a high-power input terminal (S2) for supplying a first power to the load and a low-power input terminal (S1) for supplying a second power to the load. The second power is lower than the first power The switch circuit further comprises a power switch semi-conductor device (Q1) configured for controlling a load current from at least one of the high-power input terminal (S2) and the low-power input terminal (S1) to the output terminal. A control semi-conductor device (Q2) is coupled to the power switch semi-conductor device (Q1) for supplying a control signal for controlling switching of the power switch semi-conductor device (Q1). A sensing circuit is configured to generate a sensing voltage. The control semi-conductor device (Q2) is configured to control the power switch semi-conductor device (Q1) in response to the sensing voltage. The sensing circuit comprises a first sensing resistor (R1A) and a second sensing resistor (R1B) for generating the sensing voltage such that a load current has a predetermined first peak current level corresponding to the first power, when power is supplied to the high-power input terminal, and the load current has a predetermined second peak current level corresponding to the second power when power is supplied to the low-power input terminal.

摘要翻译： 提供了一种用于开关DC-DC转换器中的自振荡开关电路，其能够使用幅度调制调光来对诸如LED的负载进行调光。 调光可用于提供两个或多个不同的光输出水平，例如可用于汽车组合尾灯和断路照明。 自振荡开关电路包括输出端子（Ton P1），用于向负载提供第一功率的高功率输入端子（S2）和用于向负载提供第二功率的低功率输入端子（S1） 。 第二功率低于第一功率。开关电路还包括电源开关半导体器件（Q1），其配置用于控制来自大功率输入端子（S2）和低功率输入端（S2）中的至少一个的负载电流 端子（S1）连接到输出端子。 控制半导体器件（Q2）耦合到功率开关半导体器件（Q1），用于提供用于控制功率开关半导体器件（Q1）的开关的控制信号。 感测电路被配置为产生感测电压。 控制半导体器件（Q2）被配置为响应感测电压来控制功率开关半导体器件（Q1）。 感测电路包括用于产生感测电压的第一感测电阻器（R1A）和第二感测电阻器（R1B），使得负载电流具有对应于第一功率的预定的第一峰值电流电平， 电力输入端子，并且当向低功率输入端子供电时，负载电流具有对应于第二功率的预定的第二峰值电流电平。

公开(公告)号：US5742165A

公开(公告)日：1998-04-21

申请号：US749936

申请日：1996-11-14

申请人： Jeroen Snelten ,  Peter H. Wardenier

发明人： Jeroen Snelten ,  Peter H. Wardenier

IPC分类号： A61B5/055 ,  G01R33/36 ,  G01V3/00

CPC分类号： G01R33/3685 ,  G01R33/34007 ,  G01R33/3628

摘要： Magnetic resonance includes predetermined frequency and which is connected, via a connection circuit (14), to a transmission and/or receiving device (11, 13) for RF signals, said connection circuit comprising a coaxial cable (41) having a central conductor (45) and a conductor sheath (47) which coaxially encloses the central conductor. Over at least a part of its length the coaxial cable (41) is enclosed, by a tubular conductor (49) having first and second ends (51, 53), a dielectric (50) being present between the conductor sheath (47) and the tubular conductor. The tubular conductor (49) has an electrical length equal to one quarter of the wavelength in the dielectric (50) of electromagnetic radiation of the predetermined frequency. The first end (51) of the tubular conductor (49) is directly electrically connected to the conductor sheath (47) and the second end (53) is connected to the conductor sheath via a capacitor (57). As a result, the physical length (1) of the tubular conductor (49) can be substantially shorter than its electrical length.

摘要翻译： 磁共振包括预定频率，并且经由连接电路（14）连接到用于RF信号的发射和/或接收装置（11,13），所述连接电路包括具有中心导体的同轴电缆（41） 45）和同轴地围绕中心导体的导体护套（47）。 在其长度的至少一部分上，同轴电缆（41）由具有第一和第二端（51,53）的管状导体（49）封闭，电介质（50）存在于导体护套（47）和 管状导体。 管状导体（49）具有等于预定频率的电磁辐射的电介质（50）中波长的四分之一的电长度。 管状导体（49）的第一端（51）直接电连接到导体护套（47），第二端（53）经由电容器（57）连接到导体护套。 结果，管状导体（49）的物理长度（1）可以比其电气长度短得多。

公开(公告)号：US5302901A

公开(公告)日：1994-04-12

申请号：US932870

申请日：1992-08-20

申请人： Jeroen Snelten

发明人： Jeroen Snelten

IPC分类号： A61B5/055 ,  G01R33/34 ,  G01R33/36 ,  G01R33/20

CPC分类号： G01R33/365

摘要： Magnetic resonance apparatus includes an RF receiver coil system (13, 15) for detecting magnetic resonance signals generated in an object. This RF receiver coil system has a first (35) and a second receiver coil (37) which could be coupled to one another by mutual inductance. In order to compensate for the mutual inductance there is provided a decoupling network. This network has a first (49) and a second terminal (51) which are connected to a first end and a second end, respectively, of the first receiver coil (35), and also a third (53) and a fourth terminal (55) which are connected to a first end and a second end, respectively, of the second receiver coil (37). The decoupling network contains a first circuit (57) of variable impedance which interconnects the first and the third terminal (49, 53) and also a second circuit (59) of variable impedance which interconnects the second and the fourth terminal (51, 55). Each of the first and second circuits (57, 59) have at least one capacitor ( 63) and at least one coil (61), the value of the capacitor and/or the coil being variable so as to enable variation of the impedance of the circuits.

摘要翻译： 磁共振装置包括用于检测在物体中产生的磁共振信号的RF接收器线圈系统（13,15）。 该RF接收器线圈系统具有可以通过互感而彼此耦合的第一（35）和第二接收器线圈（37）。 为了补偿互感，提供了一个去耦网络。 该网络具有分别连接到第一接收线圈（35）的第一端和第二端的第一（49）和第二端（51），以及第三端（53）和第四端（ 55），其分别连接到第二接收线圈（37）的第一端和第二端。 去耦网络包含​​互连第一和第三端子（49,53）的可变阻抗的第一电路（57），以及互连第二和第四端子（51,55）的可变阻抗的第二电路（59） 。 第一和第二电路（57,59）中的每一个具有至少一个电容器（63）和至少一个线圈（61），电容器和/或线圈的值是可变的，以便能够改变 电路。