Due to the enormous successes in recent years in getting out more lumen per watt, LEDs are starting to penetrate more and more illumination applications with high brightness LEDs. LEDs starting from 0.5W with drive currents between 150 to 200mA going up to several watts with drive currents of 700mA belong to the category of high brightness LEDs.
Infineon Technologies has recently issued the application note AN101 for high current applications with an unbeatable cost position for LED drivers. The AN101 based on a low cost BCR 401R in combination with a booster transistor is addressing high current applications which don’t require any frills and fancy features.
The new BCR 450 follows the same concept as described in AN101 that combines an LED Controller with an external power stage with the difference that the BCR 450 contains some more useful features than BCR 401R used in AN101. The combination of the external power stage next to an intelligent and feature-rich IC like the BCR450 is the most cost efficient solution in the industry besides the advantage of spreading the heat dissipation over two devices instead of one monolithic driver IC.
Infineon PN
Features
- Linear mode driver
- High precision current control +/- 1.6% at 25°C
- Stand alone: 10mA – 85mA (adjustable with external resistor)
- Booster circuit: 85mA – 5A
- Maximum power dissipation of booster transistor, in case of BCX68-25 - 1.5W,
- but higher power dissipation possible by usage of other booster transistors
- Over voltage protection up to 45V , maximum operating voltage 27V
- Thermal shutdown-protection for LEDs
- Low voltage overhead of 0.45V in boost operation
- Logic levels enable input, direct PWM dimmable
Applications
- High precision lighting applications
- Architectural and landscape lighting
- Aircraft lighting
- Interior/exterior building lighting
- Advertising panels
- Light bars on emergency vehicles
- EM I sensitive lighting applications
- Other types of general lighting applications
Benefits
- No EM I problems
- Differences in brightness resulting from temperature variation can be avoided
- External power stage allows improved heat dissipation in comparison to monolithic drivers
- Thermal shutdown function ensures that the LED Driver and the LEDs are protected
- Higher count of LEDs in a string due to very low voltage overhead
- Low part count, no external digital transistor or coils required
- Excellent price-performance-ratio, due to separation of power-stage from higher cost IC technology
Datasheet
Application note