Voltage to Current Converter: How It Helps Control Load Current

Using a voltage-to-current converter can help control load current. Many electronic designs emphasize voltage over current, which is why so many voltage sources have stable voltages. But sometimes steps must be taken to mirror the sources shown in theoretical circuit diagrams. Here are ways to sufficiently control load current with a voltage converter.

Current and Voltage Relationship

The amount of current in a load is affected by the amplitude of the applied voltage, as well as properties of the load's current and voltage. Resistance defines the relationship between current and voltage in a typical resistance load. Current is measured by dividing voltage by resistance, as changes in load resistance proportionally affect changes in load current.

In situations when an operator decides to specify the current, it's necessary to use a voltage-to-current converter (VCC), which also acts as a voltage-controlled current source. This voltage converter allows users to generate current that relies completely on input voltage.

When To Use Converters

A VCC is useful when working with light-emitting diodes (LEDs). Since an LED has nonlinear current-voltage properties, voltage is not always equated with the brightness of the LED lights, which is determined by current. The configuration of the circuit will determine the degree that a voltage signal will accurately control the current through a load component. The key is to use a configuration that allows differential input voltages.

An operational amplifier (also known as op amp) can be used for generating output voltage much greater than voltage within input terminals. An op amp is DC coupled and includes a differential input and typically a single-ended output. Op amps can be used as building blocks to create circuits. They work as current and voltage regulators, as well as for the following applications:

• audio frequency pre-amplifiers
• filters
• precision rectifiers
• analog calculators
• oscillators and wave form generators

A major benefit to op amps is that they can be used to control circuits with external components. Keep in mind that not every op-amp provides rail-to-rail inputs.