Patent attributes
An H.F. power amplifier is disclosed having a plurality of branches (10, 11, 12) switched in parallel. Each branch comprises a plurality of amplifier elements (T1, T4) switched in series. Resistors (R2, R5) enable the voltage (U_DS) applied to the amplifier elements (T1, T4) to be set at a fraction of a supply voltage (Ud) applied to the branches (10, 11, 12). Capacitors (C2, C4) are used to adjust the source impedance of the amplifier elements (T2, T4). In order to prevent the gate-drain voltage (U_GD) from exceeding the breakdown voltage of an amplifier element (T1, T4) and damaging the amplifier element (T1, T4), a limiting path (7) is connected according to the invention between the gate terminal (G) and the drain terminal (D) of the amplifier element (T1, T4), the limiting path (7) being switchable between a conducting state and a blocking state depending on the gate-drain voltage (U_GD).