Constant Current Vs Constant Voltage Power Supply

A constant voltage power supply receives standard line voltage 120 277vac.

Constant current vs constant voltage power supply.

Constant voltage lights are always wired in parallel. In order to ensure the leds function perfectly the self contained led driver needs to provide a constant power supply for the led. This is the type of power that is typically output from your wall outlets around the home. Although the voltage stays constant the current required from the driver goes up with the number of lights.

Similar to ballasts for fluorescent lamps or transformers for low voltage bulbs led drivers provide and regulate the necessary voltage in order to maintain a safe and consistent operation. Both constant current and constant voltage drivers act as a power supply for an led light source but the delivery methods differ. Luminaires require a steady voltage to be supplied from the driver eg 12 or 24 volts. In some cases constant current drivers matching the voltage and current requirements of both the product and the power source home vehicle etc.

For these lights the voltage is fixed by the driver but the current may vary. The important thing to keep in mind is whether the output of the power device provides a constant voltage or a constant current they are required by the led device that is receiving the power. Constant voltage drivers switch this alternating current voltage vac to a low direct current voltage vdc. Just because leds are constant current devices doesn t mean that they require a constant current power supply.

In order for that light strip to be installed in a home with a 120 volt alternating current ac wiring system the voltage would need to be reduced and converted from ac to dc with a power supply. By joshua caldwell download pdf many applications require a power supply that can accurately regulate a voltage and accurately limit output current but there are remarkably few solutions that can do both with a single ic system designers must typically trade off accuracy in. We compare constant current led drivers and constant voltage led drivers to help you pick the perfect led power supply for your application. A cc power source will maintain current at a relatively constant level regardless of fairly large changes in voltage while a cv power source will maintain voltage at a relatively constant.

The power source is monitoring the arc and making millisecond changes in order to maintain a stable arc condition.