• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

• 페이스북 공유
• 트위터 공유
• 

Power supply circuits overview Linear energy provide Switch mode power provide Capacitor smoothing AC rectifier circuits Voltage regulator circuits Zener voltage regulator circuit Over-voltage protection PSU specs Digital Power Power administration bus: PMbus Uninterruptible power supply Although fashionable energy supplies are now very dependable, there's all the time a small but actual probability that they will fail. There are many ways in which a power supply can fail. The ability provide will function usually. Obviously this form of over-voltage protection requires circuits that are particular to the actual circuit and swap mode energy supply chips used. For each linear regulated energy provides and swap mode power supplies, some form of over-voltage safety is at all times advisable. All three strategies are used and can present effective power supply over-voltage safety. Typically thyristors, i.e. SCRs are used for this as they can swap giant currents and stay on until any charge has dispersed. Be certain each halves of every coil are wound in similar course. PMI’s AC-DC power supplies are remoted and Non-isolated. This is applicable to each linear power provides and in addition to switch mode power provides. When over-voltage protection is required for switch mode power supplies, SMPS the clamp and crowbar techniques are much less broadly used due to the facility dissipation necessities and the attainable size and cost of the components.

Some power supplies might not incorporate over-voltage safety and these should not be used for powering costly gear - it is possible to perform a little electronic circuit design and to develop a small over-voltage safety circuit and add this on as an extra item. The transistor collection pass gadget would extra usually fail in an open circuit condition, but beneath some circumstances, the transistor could develop a brief circuit between the collector and emitter. Within the event of a brief circuit between the collector and emitter, or drain and supply an FET, the full unregulated enter voltage would seem in the output of the voltage regulator. For a FET, the equivalent can be a brief circuit between the drain and source. As the name implies the crowbar circuit locations a short circuit across the output of the ability provide if an over-voltage situation is skilled. Typical output with a 12 VDC 2 A energy supply or battery can be 12,000 V. Maximum output current at full voltage is usually round 1 to 2 mA. It's not doable to make use of an ohmmeter to locate the return for the excessive voltage winding in case your flyback has a built-in HV rectifier or multiplier because the ahead voltage drop of the rectifier diodes is way greater than the battery voltage utilized in your multimeter.

By including just a little additional protection circuitry in the digital circuit design stage in the type of over-voltage protection, it is feasible to protect towards this unlikely however catastrophic chance. With a big shade Tv or coloration monitor flyback, 30,000 V or more might be attainable utilizing a 24 VDC energy supply. If the collection pass transistor in the facility supply fails, the voltage will begin to rise - the decoupling within the unit will ensure it doesn't rise immediately. As it rises, it will rise above the point the place the Zener diode begins to conduct and present will circulation into the gate of the thyristor causing it to trigger. By detecting the high voltage, the circuit can fire the thyristor to position a short circuit or crowbar throughout the voltage rail to make sure it doesn't rise to high in voltage. However this capacitor should not be made too large as it might slow the circuit firing in a real case of failure and the protection could also be in place too slowly. Power provides can fail in some ways and one particularly worrying risk is that the series go ingredient of a linear power provide, i.e. important cross transistor or FET may fail in such a manner that it goes short circuit.

The thyristor will be linked again to a fuse which blows and isolates the regulator from having any additional voltage positioned upon it. Read extra about Thyristor Crowbar Overvoltage Protection Circuit. The Thyristor or SCR, Silicon Controlled Rectifier can be used to supply overvoltage protection in a power provide circuit. This means that there will be a significant stage of heat dissipated in the voltage regulator component and combined with any transient spikes that might appear on the input, this implies there is at all times a possibility of failure. Most power provides designed for very reliable operation of high worth gear will incorporate some form of over-voltage protection in the digital circuit design to make sure that any energy provide failure does not result in injury to the tools being powered. A flyback removed as a consequence of failure could also be used if it was the first that failed and the primary turns could be eliminated without damaging the HV secondary or dropping the secondary return connection! It is essential to use an external sense loop as a result of if the change mode regulator chip is damaged causing the over-voltage situation, the sense mechanism might even be damaged. This could also be a special coloration wire than the low voltage winding or could exit from the potted a part of the flyback in a distinct place.

If you have any thoughts concerning in which and how to use low voltage power line, you can get hold of us at our own web page.