LED driver eliminates audible noise during dimming
The new LED backlight driver from Allegro MicroSystems employs the patented pre-emptive boost (PEB) control to eliminate the audible noise. The A8060x family of LED drivers uses PEB control to substantially reduce V out ripple and thus eliminate the common problem of audible noise from ceramic output capacitors during PWM dimming.
That allows the lighting systems to achieve an LED brightness contrast ratio of 15,000:1 using PWM-only dimming at 200 Hz. Moreover, a higher contrast ratio of 150,000:1 is possible with a combination of PWM and analog dimming. Here, it’s worth noting that A8060x drivers boost PMW dimming ratios without analog adjustment.
The ALT80600 and A80603 LED drivers combine a switching converter with a MOSFET and four current sinks. They feature four LED strings, each capable of handling up to 120 mA with the total LED current of up to 480 mA. Next, the A80601 and A80602 devices drive an external boost FET for higher output power. And they provide a total LED current of up to 840 mA via four or six strings, respectively.
>> Read the complete article originally published on our sister site, Electronic Products: "LED driver uses a patented control method to eliminate audible noise."