Understanding the Working of a Voltage Regulator

A fixed output voltage of a preset magnitude is generated by a voltage Regulator that remains constant irrespective of changes to its load conditions or input voltage. Switching and linear are two types of voltage regulators.

An active pass device controlled by a high gain differential amplifier is employed by a linear regulator. With a precise reference voltage, it compares the output voltage, and to maintain a constant output voltage, it adjusts the pass device.

To a circuit that controls the power switch on and off times, the filtered power switch output voltage is fed back so that regardless of load current or input voltage changes, the output voltage remains constant.

Switching regulator associated losses

As a result of the power needed to turn the MOSFET on and off, Losses occur which are associated with the MOSFET’s gate driver. Also as it takes a finite time to switch to/from the conduction to no conduction states, MOSFET power losses occur. Due to the energy needed to discharge and charge the capacitance of the MOSFET gate between the gate voltage and threshold voltage, Losses occur. The Power Regulator is also useful.

Design specifications crucial for IC of a voltage regulator

The output current, output voltage, and input voltage are the basic parameters. Other parameters may be important based on the application, such as efficiency, load transient response, output ripple voltage, and output noise. Important parameters for the linear regulator are output noise, power supply rejection ratio, and dropout voltage. With a precise reference voltage, it compares the output voltage, and to maintain a constant output voltage, it adjusts the pass device.

Switching and linear regulators applications

The linear regulator’s power dissipation for a given output and input voltage is directly proportional to its output current. So, typical efficiencies can be 50% or even lower. Efficiencies in the 90% range can be achieved by using the optimum components like a switching regulator. However, as compared to a switching regulator with the same output voltage and current requirements, the noise output from a linear regulator is much lower. Typically, higher current loads can be driven by the Automatic Voltage Regulator than a linear regulator. Follow us on Facebook