Step-up / Boost converters
For low input voltages
PREMA ICs PR4401 and PR4402
For batteries (Vcc) up to 1.9 V, standard-ICs PR4401 and PR4402 can be utilized for low ILED and high ILED. Based on the applied Inductor, LED currents ranging from 6.5 mA to 40.0 mA are selectable. Importantly, further external components are not required. Thus, small, light and cost-efficient devices can be fabricated using PR4401 or PR4402.
Applications:
- supply for white or colored LEDs
- LCD background lighting (e.g. mp3-player, alarm clock)
- supply for operating display
- mini-pocket lamp (e.g. key chain, integrated into car keys)
For supply voltages up to 5.0 V
PREMA IC PR4404
The LED driver PR4404 offers the highest level of flexibility. A low ohm resistance (about 1 Ω), connected in series with the LEDs, enables a current regulation. For power LEDs, maximum currents of 150 mA or 300 mA can be applied with one or two AA/AAA batteries, respectively. LED dimming can be set by a PWM signal applied at a hold pin. Here, also blinking or switching of the LEDs becomes feasible. Inductivities of about 2 µA are already sufficient for operation.
Applications:
- LED pocket lamps
- LCD background lighting
- lighting
- toys, portable household appliances