Constant voltage power supplies are suitable for powering LEDs equipped with resistors or constant current drivers, which regulate the flow of current and may require a constant-voltage power supply when the desired operating voltage differs from the available power source (such as in homes or vehicles). 

For instance, LED light strips often incorporate current-regulating resistors. If the light strip operates within a range of 9-14.8 volts in direct current (DC), it can be directly connected to a 12-volt DC system in a vehicle without requiring a constant-voltage power supply. However, if you want to install the same light strip in a home with a 120-volt alternating current (AC) wiring system, you must reduce and convert the voltage from AC to DC using a power supply. 

In certain cases, constant-current drivers are available that match the voltage and current requirements of both the product and the power source (home, vehicle, etc.), eliminating the need for a constant-voltage power supply.

A driver and a power supply are the same thing. These terms are used interchangeably. Drivers tend to refer more to constant current power supplies.

The most common use for constant voltage power supplies is LED strip lights.

Constant voltage supplies provide a consistent voltage across the LEDs so that minimal voltage drop ensures all your LEDs work properly and effectively.

NEC Class 2 refers to the output voltage and power of AC/DC power supplies. So it focuses on wiring details like wire size, derating factors, installation, and overcurrent protection limits. Class 2 power supplies are considered less of a fire hazard and have less risk of causing electrical shocks.

On the other hand, IEC Class II refers to the internal construction of the power supply and its electrical insulation. With Class II power supplies, there are two layers of insulation, and they have a two-wire power cord.

For more details on Class 2 and Class II, read our blog “Is There a Difference Between Class 2 and Class II Power Supplies?”