LED light manufacturers are wrestling with the fact that without adequate thermal management, heat can degrade the LED’s lifespan and affect colour output.
Also, since LED drivers are typically semiconductor devices, they can fail short. This means fail-safe backup overcurrent protection may be required.
It is accepted that the optical behaviour of an LED varies significantly with temperature. The amount of light emitted by the LED decreases as the junction temperature rises and, for some technologies, the emitted wavelength changes with temperature. If drive current and junction temperature are not properly managed, the LED’s efficiency can drop quickly, resulting in reduced brightness and shortened life.
Power line coupled transients and surges can also reduce LED lifespan, and many LED drivers are susceptible to damage resulting from improper DC voltage levels and polarity. LED driver outputs may also be damaged or destroyed by short circuits.
Most LED drivers include built-in safety features, including thermal shutdown, as well as open and short LED detection. However, additional overcurrent protection devices may be needed to help protect ICs and other sensitive electronic components.
LEDs are driven with a constant current, with the forward voltage varying from less than 2V to 4.5V, depending on the colour and current. Older designs relied on simple resistors to limit LED drive current, but designing an LED circuit based on the typical forward voltage drop as specified by a manufacturer can lead to overheating of the LED driver.
Overheating may occur when the forward voltage drop across the LED decreases to a value significantly less than the typical stated value. During such an event, the increased voltage across the LED driver can result in higher total power dissipation from the driver package.
LED applications use power conversion and control devices to interface with various power sources, such as the AC line, a solar panel or battery power, to control power dissipation from the LED driver.
Also, since LED drivers are typically semiconductor devices, they can fail short. This means fail-safe backup overcurrent protection may be required.
It is accepted that the optical behaviour of an LED varies significantly with temperature. The amount of light emitted by the LED decreases as the junction temperature rises and, for some technologies, the emitted wavelength changes with temperature. If drive current and junction temperature are not properly managed, the LED’s efficiency can drop quickly, resulting in reduced brightness and shortened life.
Power line coupled transients and surges can also reduce LED lifespan, and many LED drivers are susceptible to damage resulting from improper DC voltage levels and polarity. LED driver outputs may also be damaged or destroyed by short circuits.
Most LED drivers include built-in safety features, including thermal shutdown, as well as open and short LED detection. However, additional overcurrent protection devices may be needed to help protect ICs and other sensitive electronic components.
LEDs are driven with a constant current, with the forward voltage varying from less than 2V to 4.5V, depending on the colour and current. Older designs relied on simple resistors to limit LED drive current, but designing an LED circuit based on the typical forward voltage drop as specified by a manufacturer can lead to overheating of the LED driver.
Overheating may occur when the forward voltage drop across the LED decreases to a value significantly less than the typical stated value. During such an event, the increased voltage across the LED driver can result in higher total power dissipation from the driver package.
LED applications use power conversion and control devices to interface with various power sources, such as the AC line, a solar panel or battery power, to control power dissipation from the LED driver.