MP4690 Smart Bypass For LED Open Protection

MP4690 Smart Bypass For LED Open Protection

The MP4690 is a MOSFET based smart bypass for LED open protection, which provides a current bypass in the case of a single LED fails and becomes an open circuit.

Key Specifications

Features

• Simple Two Terminal Device
• Automatic Reset if the LED Heals itself or is Replaced
• 0.22Ω Typical On-state Resistance
• Less than 1µA Off-state Current
• Available in SOD123 Package

Typical Application Circuit

Applications

• LEDs where Preventive Maintenance is not Practical
• LED Headlights
• LEDs with high Reliability Requirements
• Crowbar Protection for Open Circuit Conditions

Design Notes

• Channel-to-channel current matching sets backlight uniformity; check the matching spec at the current you will actually run.
• In boost topologies the OVP threshold must clear the worst-case forward voltage of the longest string, including temperature and binning spread.
• Keep PWM dimming above 200 Hz to stay clear of visible flicker, and away from the audio band if the product has a speaker.
• Size the inductor and output capacitor for the string current ripple, not the total LED current.

Common Questions