LED drivers with digital low-pass filters are industry’s first

LED drivers with digital low-pass filters are industry’s first

The SC652 and SC656 tiny LED charge pump drivers are claimed to be the first of their kind to integrate digital low-pass filters to convert a PWM dimming signal’s duty-cycle into dc current for LCD backlighting with white LEDs. Both parts are optimized for single-cell Li-ion battery handheld applications. The SC652 supports up to five LEDs with one PWM dimming input, while the SC656 supports up to seven LEDs with one or two independent PWM dimming inputs for end products that have multiple zones of lighting.

The PWM input accepts 200-Hz to 50-kHz PWM signals with logic level of 1.4 V and above. Additional features include an input supply of 2.9 to 5.5 V, charge pump modes of 1x, 1.5x, and 2x, a current accuracy of ±1.5% typical and a current matching of ±0.5%.

LED current is linearly proportional to duty cycle from 1% to 100%, while 0% duty cycle places the IC into 0.1-µA shutdown. The SC652 and SC656 are available in 14- and 20-pin MLPQ-UT packages, respectively. (Ea/3,000: SC652, $0.55; SC656, $0.71 — available now.)

Semtech , Camarillo , CA
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http://www.semtech.com