December 20, 2007 -Allegro® announces a new, high-brightness, adjustable constant current LED driver to complement its existing portfolio of display driver ICs. Targeted at the automotive lighting market, this LED driver is also an excellent fit in industrial and consumer LED applications. This new device is designed to operate over the typical automotive battery and temperature ranges. The input voltage range is specified down to 6 V and will operate up to a maximum of 40 V. The linear constant current output can be adjusted to deliver up to 350 mA in a typical application. An ENABLE input is used to enable the LED drive and can also be driven with a pulse-width-modulated (PWM) input for dimming of the LED brightness. To help minimize EMI, the slew rate of the output current is controlled during switching. In addition, the ENABLE pin will cause the IC to enter into a low quiescent sleep mode if held low. Typical applications for Allegro’s A6260 include: automotive interior lighting such as map lights and dome lights, and exterior lighting such as rear indicator and brake lights and rear combination lighting. Industrial and consumer high intensity LED lighting applications will also benefit from the A6260’s feature set.

Functional Block Diagram of A6260 

 

Several automotive-grade protections are featured in the integrated circuit. The IC is fully protected against shorts to ground or shorts to battery. This new IC also includes a thermal shut-down circuit (TSD) which disables the IC if the junction temperature reaches ~ 165°C. Allegro’s A6260 has integrated reverse battery protection eliminating the need for an external reverse battery diode.

The A6260 also includes a temperature monitor circuit. This circuit monitors the chip temperature and will cause the output current to reduce in a fold-back fashion. The temperature threshold at which the fold-back begins can be adjusted by choosing an appropriate resistor on the THTH pin. This feature will allow the LED driver to dynamically protect itself during any over-voltage transients on VIN (such as load-dump or double battery). If the IC is mounted on an appropriate substrate and located near the LED, this feature can also be used to help protect the LED against over-temperature conditions.

Allegro’s new LED driver is available in an 8-lead thermally enhanced SOIC package.

Features:
- Automotive grade
- LED drive current up to 350 mA
- 6 to 40 V supply
- Reverse battery protection
- Low drop-out voltage
- LED short circuit and thermal protection
- 10 µA maximum shutdown current
- PWM dimming control input
- Current slew rate limiting

About Allegro:
Allegro MicroSystems, Inc. is a leader in developing, manufacturing and marketing high-performance power integrated circuits and integrated Hall-effect magnetic sensors. Allegro’s innovative solutions serve high-growth applications within the automotive, communications, computer/office automation, consumer and industrial markets. Allegro is headquartered in Worcester, Massachusetts (USA) with design and applications centers located in North and South America, Asia, and Europe. Further information about Allegro can be found at www.allegromicro.com .