How Does a Voltage Regulator Work?

Voltage regulators function by generating a fixed output voltage and keeping the magnitude of that voltage constant despite changes to load conditions or input voltage. Two categories of voltage regulators exist: linear regulators and switching ones.

A linear voltage regulator uses an active pass device controlled by a differential amplifier at high gain. The device compares the output voltage with a reference voltage and consequently adjusts itself to compensate and maintain a consistent output voltage.

A switching voltage regulator operates by converting DC input voltage and feeding back the filtered output voltage through a circuit that controls the device's power switch, turning it on and off in such a way as to maintain constant output voltage.

Electricians can design switching regulators with various switching frequencies. The benefit of using higher switching frequencies is that the device can be constructed with smaller capacitors and inductors. The disadvantage of this, however, is that the circuit is more prone to noise and switching losses. Losses generally occur due to the power consumption of the device switch and the amount of time it takes for the switch to physically operate. Generally, linear voltage regulators provide significantly less noise output, while switching regulators are capable of driving higher current loads.