A voltage reference is a piece of electronic equipment that basically generates a specified current regardless of the equipment overload, voltage supply changes, temperature variations, and the passage of time. Power supplies, analog-to-digital converters, digital-to-analog converters, and other measurement and control systems all require voltage. The performance of voltage varies greatly; a computer power supply regulator could only be able to maintain its value to a few percent of the nominal value, whereas laboratory voltage standards have precisions and stability measured in parts per million.
Why Do We Use Voltage?
A reference voltage must remain constant regardless of system variables like input voltage or outside temperature for measurements to be accurate. A voltage-reference IC delivers a constant voltage that other ICs can utilize to take accurate measurements.
Common Types of Voltage Reference
Voltage can be classified into three categories: bandgap, zener, and charged capacitor.
- Due to ionizing radiation's volatility, the charged capacitor is rarely employed. The capacitor is discharged by alpha, beta, gamma, cosmic rays, or regular x-rays used at airports, hospitals, and transportation security.
- Zener employed both in and out of avalanche mode is the second kind of common voltage reference. Most avalanche mode zeners are utilized above around 5.5V, depending on the semiconductor process, where they would be most stable (i.e., at a steep knee).
- Bandgap is an inventive use of two transistor junctions with various current densities and thus various temperature coefficients. To create a virtually flat temperature curve, two voltages with opposite temperature coefficients are subtracted from one another.
Applications of Voltage
Voltage is employed to offer a very precise current for measurements to be made against. The precision of any measurement is as efficient as the capability to make a comparison against a defined standard.
High-resolution A/D converters and D/A converters, digital meters, smart sensors with threshold detectors, servo systems, battery management, precision regulators, and many other precision industrial control systems require a precision voltage reference at their core.
