Constant Current vs. Constant Voltage LED Drivers

This page compares constant current LED drivers and constant voltage LED drivers, highlighting the key differences between them.

Constant Current LED Driver

• This type of driver is used to power LEDs that require a fixed output current, with a specified voltage range.
• As shown in the figure above, the constant current is 700 mA, and the output voltage range is 4 to 13 V DC.
• In this LED driver, typically only one output current is mentioned (in units of Amps or milliamps), along with a voltage range that varies based on the wattage of the LED.

Constant Voltage LED Driver

• This type of driver is used to power LEDs that require a fixed output voltage, with a specified maximum current.
• As shown in the figure above, the constant voltage is 24V DC, and the output current is 1.04 Amp (maximum).
• In this LED driver, usually one stable voltage is used, rather than a range of voltages.
• Here, the current is regulated either using resistors or using an internal constant current driver within the LED module.

AC LED Driver

There’s also another type of LED driver known as an AC LED driver. It’s essentially a no-minimum load transformer. This means it can also be used to operate low-voltage halogen or incandescent bulbs.

AC LED drivers are typically used with bulbs that already have an internal driver. This internal driver converts AC current to DC current. Therefore, the AC LED driver’s job is to register the low wattage of the LEDs and subsequently step down the voltage to meet the bulb’s voltage requirement (usually 12 or 24 volts).