電容在醫(yī)療器械中的使用，可以減少波紋并吸收開關(guān)穩(wěn)壓器產(chǎn)生的噪音等好處，醫(yī)療設(shè)備需要對電源進(jìn)行高精度的控制和調(diào)節(jié)，才能支持設(shè)備執(zhí)行每一功能。交、直流電源均被廣泛應(yīng)用于這些場合。為保證可靠工作，必須降低鉭電容的額定電壓。例如，額定值為10uF/35V的D型鉭電容，工作電壓應(yīng)降低到17V，如果用在電源輸入端過濾紋波，額定35V鉭電容可在高達(dá)17V的電壓導(dǎo)軌上可靠地工作。
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.
高壓電源總線系統(tǒng)一般很難達(dá)到額定電壓降低50%的指標(biāo)。這種情況限制了鉭電容用于電壓導(dǎo)軌大于28V的應(yīng)用。目前，由于鉭電容需要被降額使用，高壓濾波應(yīng)用一個可行的辦法是采用體積較大且?guī)б€的電解電容，而不是鉭電容。
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.
選擇電容的方法
Method of selecting capacitance
新型鉭電容
New tantalum capacitor
為解決降低額定電壓的問題，采用鉭電容，可達(dá)到額定電壓降低50%的行業(yè)認(rèn)可安全指標(biāo)。電介質(zhì)成形更薄、更一致，使SMD固體鉭電容的額定電壓能夠達(dá)到75V，從而實現(xiàn)了提高額定電壓的技術(shù)突破。成形工藝中對多道工序進(jìn)行了改進(jìn)：降低了成形加工過程中產(chǎn)生的機(jī)械應(yīng)力集中，降低了電容成形過程中電解液的局部過熱，提高了電介質(zhì)成形過程中電解液濃度和純度的一致性。
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.
無線感應(yīng)耦合充電
Wireless inductive coupling charging
大量的感應(yīng)充電器采用返馳式轉(zhuǎn)換器。感應(yīng)充電為醫(yī)療設(shè)備電池提供充電電能，同時，感應(yīng)充電器也被用于大量的便攜式設(shè)備（如牙刷）中?？s小充電電池尺寸有助于減小采用無線感應(yīng)充電電路的植入式醫(yī)療設(shè)備的體積。無線感應(yīng)充電器可為設(shè)備上安裝的微小薄膜充電式儲能器件安全地充電。感應(yīng)充電器采用了并聯(lián)LC（電感、電容）諧振儲能電路的工作原理。
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.
在一些電壓較高的感應(yīng)充電器應(yīng)用中，需要采用高壓穩(wěn)定的電容作為諧振電容。由于感應(yīng)充電器的初級線圈需要采用交流電壓驅(qū)動，因此必須對電容進(jìn)行相應(yīng)的調(diào)整。感應(yīng)充電器需要具備高擊穿電壓（VBD）性能，同時，某些應(yīng)用中還需要防護(hù)高壓電弧放電。為避免電弧放電，電路板一般敷有保護(hù)涂層，或者通過合理安排元器件布局達(dá)到高壓側(cè)與電路板其他部分隔離的效果，等。但這種方法往往需要很大的電路板空間，因為高壓電路通常采用體積較大的引線型通孔插裝電容。
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.
高壓電弧防護(hù)電容解決方案
High voltage arc protection capacitor solution
為解決這一問題，一系列的HVArc（高壓電?。┓雷o(hù)MLCC（多層貼片陶瓷電容）可防止電弧放電，同時節(jié)省空間。這些新器件在較高的電壓定額內(nèi)具有大容量，并且提高了電壓擊穿的耐受能力。高壓電弧放電會造成斷路，并有可能損壞其他元器件。標(biāo)準(zhǔn)的高壓SMD電容將會失效短路，這取決于電弧放電的次數(shù)和存在問題的部分。因此，此電容能夠在高壓下進(jìn)行正常工作，至少在達(dá)到高壓擊穿極限之前，不會產(chǎn)生破壞性電弧放電。
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的新型無磁電容
New non magnetic capacitors for MRI
磁共振成像（MRI）設(shè)備內(nèi)部或周邊電路中所使用的電容及其他電子元器件需要屏蔽或封裝在MRI室外。電容的電介質(zhì)、電極材料或端接材料中可能含有鐵質(zhì)或磁性材料。為提高圖像分辨率，MRI系統(tǒng)的磁場水平不斷提高，而MRI室內(nèi)使用的電容會造成磁場畸變。因此，需要減少或完全消除大部分電容中的磁性材料。
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.