Abstract: Various exemplary embodiments relate to a current driver for controlling a current source controlled by an alternating current (AC) signal, including: a current sensor configured to measure an output current from the current source; a threshold detector configured to detect when the measured current is below a threshold value; and a controller configured to control the current source using a duty cycle of the AC signal when the measured current is below the threshold.

Abstract: A method for an up-down converter which is based on a buck converter during the current down-conversion phase (?2, ?3 and ?5, ?6, respectively) of the coil (L1) supplies an output (B) with a relatively high output voltage (UB), where UB>Uin. The down-conversion phase of the coil current (IL1) comprises at least two different down-conversion phases (?2, ?3 and ?5, ?6, respectively). A method for an up-down converter, which converter is based on a boost converter, supplies during the current up-conversion phase (?7, and ?10, respectively) of the coil (L2) an output (D) which has a relatively low output voltage (UD) with power, where UD>Uin. The up-conversion phase of the coil current (IL2) comprises at least two different current reduction phases (?7, ?8 and ?10, ?11, respectively).