Catalyst Semiconductor CAT3604V: Quad-mode fractional-charge pump requires no additional capacitors

The CAT3604V quad-mode fractional-charge pump drives as many as four LEDs. Quad-mode technology provides inductor-based LED-driver efficiency levels and claims to eliminate high-profile inductors and EMI (electromagnetic interference). In addition to the three operating modes typical for charge-pump LED drivers and corresponding to the ratio of V_OUT to V_IN (1×, 1.5×, and 2×) the device adds a fourth, 1.33×. Requiring no additional capacitor, the 1.33× fractional-operating mode reduces the input-switching currents at the battery, reducing supply noise. Additional features include high average efficiency; a PWM (pulse-width-modulation) dimming interface; and channel diagnostics, including automatic detection for short- and open-LED-channel conditions. The CAT3604V costs 48 cents (10,000).

Catalyst Semiconductor, www.catsemi.com