An auxiliary power source (HQ) constructed with conventional components for generating an auxiliary voltage lying above the voltage of a power supply source (U1), in particular for triggering an n-channel MOS transistor (T11) used as a high-side switch for switching a load (I1). An energy store (L1) is connected via a switching element (T1) to the power supply source (U1) and an auxiliary voltage is generated at a power output (U3).