Linjerreglering

Linjerreglering, or line regulation, is a specification used for voltage regulators that describes how strongly the output voltage responds to changes in the input line voltage. It measures the sensitivity of Vout to variations in Vin, and is typically expressed as a change in output per volt of input (for example in mV per volt) or as a percentage of Vout per volt. Linjerreglering is distinct from load regulation, which describes how the output changes when the load current varies while the input line remains fixed.

Measurement of linjerreglering is normally performed under defined conditions, with a specified load current and temperature, while Vin is swept within the regulator’s permitted input range. The resulting change in Vout is recorded. Because regulators can be used in a wide range of applications, the test conditions (load, temperature, output capacitor, and Vin range) are important for meaningful comparisons.

In practice, a small linjerreglering means stable output voltage despite fluctuations in the input supply, which is important for precision analog circuits, instrumentation, and other sensitive electronics. Poor linjerreglering can cause drift in reference-based circuits, increased error in ADC measurements, and degraded overall accuracy.

Designers improve linjerreglering through several approaches. These include tighter voltage references and higher open-loop gain, cascaded regulation stages, and improved power-supply rejection ratio (PSRR). Proper choice and placement of output capacitors with low equivalent series resistance (ESR) help stabilize the regulator’s feedback loop. In switching regulators, additional pre-regulation stages or post-regulation can also enhance line stability.

Linjerreglering is a key parameter in the specification and selection of power supplies for any application where voltage stability under fluctuating input conditions is important.