Littelfuse, Inc. has introduced the PLED5 circuit protection device that provide unique 3-in-1 protection for LED strings, including open LED protection, ESD and lightning protection, and protection against reverse battery/power connections. The new device is particularly useful for maintaining brightness and reliability in the growing market for outdoor LED lighting and high-intensity LED applications.

The PLED design is a voltage-triggered electronic shunt device that provides a current bypass in the case of a single LED failing into an open circuit condition. The design ensures against the loss of an entire string of LEDs due to the failure of a single LED.

This is the latest protection device from Littelfuse targeted for the new wave of LEDs that are being implemented in a wide range of applications ranging from advertising lighting, and traffic lighting to aircraft lighting and runway lighting. The demand for high reliability in these applications places a premium on the correct circuit design approach. In addition, the high-intensity white/blue/green LEDs typically used in these applications implement a sapphire substrate that may have a low ESD tolerance level. Because of this weakness, these LED strings need appropriate ESD protection.

When the Littelfuse PLED5 string protectors are compared with conventional LED protection measures, the device provide a simpler and more economical circuit design, reduce LED color unevenness, and prevent voltage level sags in the power supply typically observed when zener diodes are used, thus resulting in higher energy efficiency.

Here are some key advantages of the PLED5 device:

# Brightness of the LED string is maintained if an LED in the string fails open.
# Small footprint makes them inconspicuous and easy to fit.
# Low on-state resistance allows high LED current flow and reduces color unevenness.
# 3-in-1 protection (open-defect protection, reverse polarity protection, ESD/lightning surge protection) allows for lower-cost solution than available from other device suppliers.
# Open defects can be controlled without negatively affecting power supply voltage.
# Ideal for outdoor lighting fixtures where maintenance cost is high.
# Fast switching
# Auto-reset after power cycle

Availability

PLED5 Series samples are available now for order and sample request through authorized Littelfuse distributors worldwide. The PLED5 LED string protector devices are available 8-12 weeks ARO, in 3000 quantity reel pack for the QFN version.