How to choose the capacitor switching power supply?

2021-07-10 09:41

Switching power supply for control of the power supply, because of its significant advantages, switching power supply has become the standard power most of the electronic products. The capacitor can be used to reduce the ripple and noise absorption switching regulator is generated, it can also be used for post regulator,improve the stability and transient response capability of equipment. Anyripple and noise or residual jitter should not power output. These circuits used tantalum capacitors to reduce the ripple, but may beaffected by the noise of tantalum capacitor switching regulator and the unsafe transient phenomena.

In order to ensure the reliable work, must reduce the tantalum capacitor rated voltage. Model of tantalum capacitors

In order to solve the problem of lower rated voltage, Vishay R & D a new series of SMD solid tantalum capacitor rated voltage levelis more developed, with rated voltage up to 75WVDC.50V, rated voltage of capacitor in 28V and higher voltagerails caused thedesigners worried, and the Vishay model of 63V and 75V tantalumcapacitor can reach the rated voltage, reduce industry recognizedsafety index50%. Dielectric forming a thin, uniform, the rated voltage of SMD solid tantalumcapacitor can reach 75V, so it can improve the technological breakthrough of rated voltage. The forming process of multi-channel processes are proposed: reducing the forming process of the mechanical stress concentration, reduce the local overheating capacitor forming process in the electrolyte, increasing the consistencyof dielectric forming electrolyte concentration and purity process.

Rated voltage of capacitor T97 series of up to 75V, 83 series of 63V.

Charging wireless inductive coupling Induction charger to extensive use of flyback converter. Induction charger to extensive use offlyback converter. Inductive charging supply charging power for medical equipment, battery at the same time,induction charger is alsoused in portable devices (such as a toothbrush).

An implantable medical device battery size helps to reduce the wireless inductive charging circuit reduced volume.

Wireless induction charger for micro film installed on the device (such as CymbetEnerChip) rechargeable energy storage devicesecurity charge. Induction chargeradopts parallel LC (inductance, capacitance) principle of resonant tank circuit.

Figure 1 shows the RF induction charger CBC- EVAL-11 Cymbet evaluation kit.Vishay 595D series 1000uF tantalum capacitor is used as the Cymbet receiving circuit board of C5 capacitor, as the radio emission and the load to provide pulse current. Vishay 595D series 1000uF tantalum capacitor is used as the Cymbetreceiving circuit board of C5 capacitor, as the radio emission and the load to provide pulse current. Has good isolation between the input and output of theinduction charger, which is an important requirement formedical equipment.

In the induction charger application of some high voltage capacitor, need highstability as the resonant capacitor. Since inductioncharger primary coil need to adopt AC voltage driving, so we must carry on the corresponding adjustment to thecapacitor.

Induction charger must have high breakdown voltage (VBD) performance, at the same time, some applications also need protection of high voltage arc discharge. In order to avoid arc discharge, circuit board with a protective coating of generalapplication,or through the rational arrangement of components and circuit boardlayout to achieve high voltage side isolated from the rest of theeffect, etc.. But this method is often required board space greatly, due to the high voltage circuitusually adopts larger leaded through-hole capacitors. But this method is oftenrequired board space greatly, due to the high voltage circuit usually adopts largerleadedthrough-hole capacitors. High voltage arc protection capacitor solutions

In order to solve this problem, Vishay launched a series of HVArc (high voltage arcprotection (MLCC) multilayer chip ceramic capacitor), can prevent arc discharge,while saving space.

These new devices have a maximum capacity at the higher voltage rating, and improve the voltage breakdown of tolerance. High voltage arc discharge will cause the circuit breaker, and has the potential to damage other components. StandardSMD high voltagecapacitor will eventually fail short circuit, depending on the number of arc discharge and the existing problems of the part. VishayHVArcprotection capacitor can absorb all the energy, therefore, the capacitor can work normally under high pressure, at least before reaching the high voltage breakdownlimit, does not produce destructive arc discharge. Vishay HVArc protection capacitor can absorb all the energy, therefore, the capacitor can work normallyunder high pressure, at least before reaching the high voltage breakdownlimit,does not produce destructive arc discharge.

The unique design of VBD distributed HVArc protection capacitor by a device usedto control, VBD is 3kV or above. This product uses the NPO and X7R dielectrics.

New magnetic capacitor for MRI

Magnetic resonance imaging (MRI) capacitor equipment used in internal or peripheral circuits and other electronic componentsrequires shielding orencapsulated in MRI outdoor. May contain iron or magnetic material, electrode material for capacitor dielectricmaterial or termination. In order to improve theimage resolution, the magnetic field level MRI system continuously improve, and the capacitor MRI indoor use will cause magnetic field distortion. Therefore, the need to reduce or completely eliminate most capacity ofmagnetic material.

Series MLCC is the latest in the electrode and the terminal structure using non ferrous materials, to meet the requirements of the elimination of magnetization. No magnetic structure can use X7R and NPO dielectrics. Size of 0402 to 1812,according to EIA specifications. Vishay is still the final test adopts special capacitor sorting equipment, to ensure that all non magnetic capacitor canmeet the technical requirements.