Power adapter, usually refers to a DC regulated switching power adapter , is a rapidly developing discipline in electronic engineering. Therefore, the specialized terminology used to describe them is also still evolving and has not yet achieved consensus and a complete definition. The following list of terms, although not comprehensive, provides a general understanding. In some cases, the common meaning of a term may differ from its special meaning in power adapter applications. In such cases, the “common meaning” is given first, followed by the “special meaning” in power adapter applications.
1.Efficiency: The ratio of output power to input power expressed as a percentage. (Note that due to the impact of power factor limits, active power is used for calculation. Switching power adapters typically use capacitive input filters with a power factor of about 0.63).
2.Thermal Protection: A method to prevent a switching power adapter from failing under overheating conditions. The power can be automatically shut off when a critical component exceeds the specified temperature.
3.Overvoltage Protection Circuit (OVP): An independent circuit that prevents the output voltage from exceeding the specified maximum limit when the control circuit fails. When the output voltage is too high, this power protection circuit can shut off the power or short-circuit the power output terminal to ground.
4.Line Regulation: The percentage change in output caused by changes in the supply voltage over the entire input voltage range.
5.Load Regulation: The percentage change in the controlled output parameter caused by a defined load change. The output change is usually expressed as a percentage of the defined load change.
5.Mean Time Between Failure (MTBF): The average time between two failures, expressed in hours. In an ideal state, it is a statistical prediction of possible failures that can be measured based on actual operating data. Predictions are more often based on a recognized standard statistical analysis.
6.Common-Mode Ripple and Noise: The voltage or current component of ripple and noise that exists between the input or output circuit and a specified ground terminal.
7.Constant-Current Limit: A part of unwanted interference energy that is conducted along the input or output terminal of a switching power supply. Conductive EMI is regulated by national and international standards.
8.Constant-Current Limit: A method of overload protection that keeps the output current constant regardless of changes in the load resistance within the overload protection range.
9.Constant-Current Supply: Any high-impedance current source whose current is basically constant and independent of the load device.
10.Constant-Voltage Supply: A power supply whose main controlled parameter is the output voltage.
11.Converter: A term commonly used in switching power supplies that converts input DC voltage to output DC voltage and uses a transformer for isolation.
12.Dynamic Load: An active load that can vary during loading. It is used to test the transient response of switching power supplies. It can also refer to an adjustable fixed current electronic load used for testing.
13.Ambient Temperature: The temperature at which a switching power adapter operates.
14.Ground Loop: A noise-generated current loop that is usually generated to make multiple common output terminals of a power supply grounded. In switching power supplies, the ground loop is often minimized by grounding the common output of the power supply. If the system requires other grounding terminals, a common-mode inductor can be connected to the output terminal to minimize the loop current.
15.Holdup Time: The time during which the output voltage of a switching power supply remains within its specified range after the input AC power is removed.
16.Inrush Current: The peak input current value that flows into the power supply when the power transformer is first turned on.
17.Leakage Current: The current that flows between two isolated components. In medical IEC60601-1 standard switching power supply applications, the leakage current of the ground loop must be very low for safety reasons. In this application, any current returning to the ground through any input filter is considered part of the leakage current.
18.Choke: An inductor specially designed to transmit large DC current components. To prevent magnetic saturation, the choke usually has a gapped magnetic core or a special low-permeability magnetic core.
19.Bleeder Resistor: Its main purpose is to provide a load. For safety reasons, it can be used to discharge capacitors or pre-set loads at the output of a switching power supply to prevent the output voltage from rising too high after the external load is disconnected. It is also called a dummy load resistor or pre-set load resistor.
20.Short-Circuit Protection: A method of overload protection that prevents the power supply from being damaged when the output terminal is short-circuited. In some flyback switching power supplies, they can withstand short circuits but cannot withstand long-term overloads or short circuits.
21.Bandwidth: It describes the frequency response of a system, usually referring to the frequency difference between the high-frequency half-power point (3dB down) and the low-frequency half-power point (3dB down) or the frequency range of the 3dB down. When used in switching power supplies, it usually refers to a frequency range in which the output ripple and noise components are specified or measured.
Post time: May-25-2023