A power supply
system comprises a
parallel arrangement of a
linear amplifier (LA) and a DC-
DC converter (CO). The
linear amplifier (LA) has an
amplifier output to supply a first current (II) to the load (LO). The DC-
DC converter (CO) comprises: a converter output for supplying a second current (12) to the load (LO), a first
inductor (L1), and a switch (SC) coupled to the first
inductor (L1) for generating a current in the first
inductor (L1), and a low-pass filter (FI) arranged between the first inductor (L1) and the load (LO). The
low pass filter (FI) comprises a first
capacitor (C1; CA) which has a first terminal coupled to the switch (SC) an a second terminal coupled to a reference
voltage level (GND), and a second inductor (L2; LC) which has a first terminal coupled to the first inductor (L1) and a second terminal coupled to the load (LO). The low-pass filter further comprises, either: (i) a series arrangement of a second
capacitor (C2) and a damping
resistor (R2), which series arrangement is arranged in parallel with the first
capacitor (C1), or (ii) a
parallel arrangement of a third capacitor (CB) and a damping
resistor (RB) arranged in series with the first capacitor (CA), or (iii) a series arrangement of a third inductor (L3) and a damping
resistor (R3), which series arrangement is arranged in parallel with the second inductor (L2), or (iv) a
parallel arrangement of a fourth inductor (LD) and a damping resistor (RD), which parallel arrangement is arranged in series with the second inductor (LC).