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About ripple and noise
AC/DC Power Adapter, this is a feature page about ripple and noise in switching power supplies. It provides basic knowledge about ripple and noise and describes their relationship with AC/DC Power Adapter. If you have any questions, please feel free to contact us.
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"Ripple" and "Noise" are items that indicate the performance of an AC/DC Power Adapter. In our specifications, they are described as follows. (Excerpt from UNIFIVE Products specifications)
| Item | Specification | Min | Typical | Max |
|---|---|---|---|---|
| Output Voltage | 24V | |||
| Output Voltage Range | Typical Output Voltage | 22.8V | 25.2V | |
| Load Current | 1A | |||
| Ripple | Input Voltage (typ), Full Load Current, 25C | 150mV | ||
| Noise | Input Voltage (typ), Full Load Current, 25C | 150mV | ||
| Hold-up Time | Input Voltage (typ) and Full Load, 50Hz | 10mS | ||
| Start-up Delay Time | 2S |
Both "Ripple" and "Noise" indicate minute fluctuations contained in the DC output voltage. Ideally, they should be 0 (zero), but in principle it is difficult to eliminate them completely. Therefore, how small they are determines the performance of the AC/DC Power Adapter.
However, smaller does not necessarily mean a "better AC/DC Power Adapter". Reducing "Ripple" and "Noise" affects the number and size of components used, resulting in a larger, heavier, and more expensive product.
Therefore, it is necessary to select an AC/DC Power Adapter with optimal performance suited to the equipment in which it will be used.
Now, regarding the difference between "Ripple" and "Noise", the standards of the Japan Electronics and Information Technology Industries Association (JEITA) define them as shown in the figure below.
(Excerpt from JEITA standards)
"Ripple" refers to fluctuations composed of frequency components of 50/60Hz from the AC power supply, while "Noise" refers to fluctuations composed of frequency components of several tens of kHz or higher generated by the switching operation of the AC/DC Power Adapter. The combination of these is called "Ripple Noise", and the relationship is "Ripple", "Noise" < "Ripple Noise" < "Ripple" + "Noise".
We offer a wide range of AC/DC Power Adapter according to your application, and individual specification sheets are available for download. Please take a look. We also specialize in custom solutions. If you have any questions, please feel free to contact us. We respond to our customers' "It would be great if this existed..." needs.
You can download the Products catalog in PDF format.
The JEITA standards introduced this time can be purchased from the page below. Some are available for free viewing only, so please refer to the details there.