Designing with Shunt Regulators

Shunt regulators are being increasingly used in microcontroller designs. Traditionally, one of the biggest roadblocks in designing microcontroller applications is selecting an appropriate power supply.

Custom power supplies have solved many of these problems but there are still some small problems. Adding shunt regulators is one way to make such designs a reality. So how do shunt regulators work?

Shunt regulators create a path between the supply voltage and the ground, using a variable resistance. These are very low on the complexity scale. Many times, the shunt regulator is just a voltage reference diode.

They are used in many low powered circuits where the wasted current is too little to be of any major concern. You can also find them in many voltage reference circuits. In fact, many DC power supplies use a shunt regulator to regulate voltage.

There are many types of shunt regulators, categorized according to their reference voltage, accuracy, operating range and packaging type. The reference voltage of a shunt regulator can be between 1.24V which can go up to 36 V.

The inclusion of shunt regulators can simplify control circuits that operate at voltages above the microcontroller’s normal range. Such a circuit can also supply power to other devices connected to the circuit. All the embedded engineer needs to do is design the circuit and select components, carefully.