Device Family Achieves Ultra-Wide True PWM Dimming Ratio, in Small 4x4 Packages
Allegro MicroSystems has announced the A8060x family, its latest generation of advanced LED backlight controllers. The family of devices is designed with an innovative PEB (Pre-Emptive Boost) control, which eliminates noise normally heard. The PEB control in the A8060x family substantially reduces Vout ripple and eliminates the common problem of audible noise from output ceramic capacitors during PWM dimming, while also requiring less overall output capacitance. Systems can achieve a 15.000:1 LED brightness contrast ratio using PWM-only dimming at 200 Hz. A ratio greater than 150.000:1 is possible when using a combination of PWM and analog dimming. “This family of LED drivers alleviates customer pain points in the areas of audible noise and device footprint,” explains Mark Gaboriault, Allegro's Director of Marketing for DC/DC Dimmers and LED Drivers.
“The A8060x family offers excellent PMW attenuation ratios without analog adjustment and eliminates noise emitted by ceramic capacitors, making them perfect for automotive applications.” The ALT80600 and A80603 combine a switching converter with integrated MOSFET and four current sinks, while the A80601 and A80602 drive an external boost FET for higher output power. All devices can be configured in a single-ended primary inductor converter (SEPIC) or boost topology to cover a wide range of application configurations. Switching converters are designed for low EMI, including programmable switching frequency, controlled switching slew rate, and programmable dithering.
Additionally, a clock output pin allows other switching converters to be synchronized with the A8060x switching frequency to improve overall system EMI performance. The A8060x family of devices is ideal for all types of automotive backlighting, including audio and video systems, as well as instrument clusters and head-up display (HUD). These devices offer a wide input range from a single 4,5 to 40V power source - once started it can continue to run down to 3,9V. This allows parts to withstand start/stop function, motion cold crankshaft, double battery and loss of charge conditions in automotive systems.
The A8060x is a robust family with a number of safety and security features required for automotive applications. The ALT80600 and A80603 models feature four LED strings, each capable of up to 120mA with a total LED current of up to 480mA. The A80601 and A80602 provide up to 840mA total LED current, through 4 or 6 strings, respectively. All of these devices are available in a compact 24x4 QFN-4 wettable flank package with exposed thermal pad (ES suffix), a smaller package than the direct competition.
