电容在医疗器械中的使用，可以减少波纹并吸收开关稳压器产生的噪音等好处，医疗设备需要对电源进行高精度的控制和调节，才能支持设备执行每一功能。交、直流电源均被广泛应用于这些场合。为保证可靠工作，必须降低钽电容的额定电压。例如，额定值为10uF/35V的D型钽电容，工作电压应降低到17V，如果用在电源输入端过滤纹波，额定35V钽电容可在高达17V的电压导轨上可靠地工作。
The use of capacitors in medical devices can reduce ripple and absorb the noise generated by switching regulators. Medical devices need high-precision control and adjustment of power supply to support the equipment to perform every function. AC and DC power supply are widely used in these occasions. In order to ensure reliable operation, the rated voltage of tantalum capacitor must be reduced. For example, D-type tantalum capacitor with rated value of 10uF / 35V should be reduced to 17V. If it is used to filter ripple at the power input, the rated 35V tantalum capacitor can work reliably on the voltage rail up to 17V.
高压电源总线系统一般很难达到额定电压降低50%的指标。这种情况限制了钽电容用于电压导轨大于28V的应用。目前，由于钽电容需要被降额使用，高压滤波应用一个可行的办法是采用体积较大且带引线的电解电容，而不是钽电容。
It is difficult for high-voltage power bus system to reduce the rated voltage by 50%. This situation limits the application of tantalum capacitors in voltage guide greater than 28V. At present, because tantalum capacitors need to be de rated, a feasible way to apply high voltage filter is to use electrolytic capacitors with large volume and leads instead of tantalum capacitors.
选择电容的方法
Method of selecting capacitance
新型钽电容
New tantalum capacitor
为解决降低额定电压的问题，采用钽电容，可达到额定电压降低50%的行业认可安全指标。电介质成形更薄、更一致，使SMD固体钽电容的额定电压能够达到75V，从而实现了提高额定电压的技术突破。成形工艺中对多道工序进行了改进：降低了成形加工过程中产生的机械应力集中，降低了电容成形过程中电解液的局部过热，提高了电介质成形过程中电解液浓度和纯度的一致性。
In order to solve the problem of reducing the rated voltage, tantalum capacitor is used to achieve the industry recognized safety index of reducing the rated voltage by 50%. The dielectric forming is thinner and more consistent, so that the rated voltage of SMD solid tantalum capacitor can reach 75V, thus realizing the technical breakthrough of improving the rated voltage. In the forming process, the mechanical stress concentration is reduced, the partial overheating of electrolyte is reduced, and the consistency of electrolyte concentration and purity in dielectric forming process is improved.
无线感应耦合充电
Wireless inductive coupling charging
大量的感应充电器采用返驰式转换器。感应充电为医疗设备电池提供充电电能，同时，感应充电器也被用于大量的便携式设备（如牙刷）中。缩小充电电池尺寸有助于减小采用无线感应充电电路的植入式医疗设备的体积。无线感应充电器可为设备上安装的微小薄膜充电式储能器件安全地充电。感应充电器采用了并联LC（电感、电容）谐振储能电路的工作原理。
A large number of induction chargers use flyback converters. Inductive charging provides charging power for batteries of medical devices. At the same time, inductive chargers are also used in a large number of portable devices (such as toothbrushes). Reducing the size of rechargeable batteries helps to reduce the volume of implantable medical devices using wireless induction charging circuits. The wireless induction charger can safely charge the micro film charging energy storage device installed on the device. The working principle of parallel LC resonant energy storage circuit is adopted in the induction charger.
在一些电压较高的感应充电器应用中，需要采用高压稳定的电容作为谐振电容。由于感应充电器的初级线圈需要采用交流电压驱动，因此必须对电容进行相应的调整。感应充电器需要具备高击穿电压（VBD）性能，同时，某些应用中还需要防护高压电弧放电。为避免电弧放电，电路板一般敷有保护涂层，或者通过合理安排元器件布局达到高压侧与电路板其他部分隔离的效果，等。但这种方法往往需要很大的电路板空间，因为高压电路通常采用体积较大的引线型通孔插装电容。
In some high voltage applications of induction chargers, it is necessary to use high voltage stable capacitors as resonant capacitors. Because the primary coil of induction charger needs to be driven by AC voltage, the capacitance must be adjusted accordingly. Induction chargers need to have high breakdown voltage (VBD) performance, and some applications also need to protect against high voltage arc discharge. In order to avoid arc discharge, the circuit board is generally coated with protective coating, or the high voltage side is isolated from other parts of the circuit board by reasonable arrangement of component layout. However, this method often requires a lot of circuit board space, because the high-voltage circuit usually uses large lead-in plug-in capacitors.
高压电弧防护电容解决方案
High voltage arc protection capacitor solution
为解决这一问题，一系列的HVArc（高压电弧）防护MLCC（多层贴片陶瓷电容）可防止电弧放电，同时节省空间。这些新器件在较高的电压定额内具有大容量，并且提高了电压击穿的耐受能力。高压电弧放电会造成断路，并有可能损坏其他元器件。标准的高压SMD电容将会失效短路，这取决于电弧放电的次数和存在问题的部分。因此，此电容能够在高压下进行正常工作，至少在达到高压击穿极限之前，不会产生破坏性电弧放电。
To solve this problem, a series of hvarc (high voltage arc) protection MLCC (multilayer ceramic chip capacitor) can prevent arc discharge and save space. These new devices have large capacity within a high voltage rating and improve the withstand ability of voltage breakdown. High voltage arc discharge will cause open circuit and may damage other components. The standard high voltage SMD capacitor will fail and short circuit, depending on the number of arc discharges and the part with problems. Therefore, the capacitor can work normally under high voltage, and will not produce destructive arc discharge at least until the high voltage breakdown limit is reached.
用于MRI的新型无磁电容
New non magnetic capacitors for MRI
磁共振成像（MRI）设备内部或周边电路中所使用的电容及其他电子元器件需要屏蔽或封装在MRI室外。电容的电介质、电极材料或端接材料中可能含有铁质或磁性材料。为提高图像分辨率，MRI系统的磁场水平不断提高，而MRI室内使用的电容会造成磁场畸变。因此，需要减少或完全消除大部分电容中的磁性材料。
Capacitors and other electronic components used in the internal or peripheral circuits of magnetic resonance imaging (MRI) equipment need to be shielded or packaged outside the MRI room. The dielectric, electrode material or termination material of the capacitor may contain iron or magnetic material. In order to improve the image resolution, the magnetic field level of MRI system is constantly improved, and the capacitance used in MRI room will cause magnetic field distortion. Therefore, it is necessary to reduce or completely eliminate the magnetic materials in most capacitors.