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.
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.