A switching amplifier circuit comprising: an output driving circuit comprising a high side split gate-source switching transistor and low side split gate-source switching transistor connected in series between first and second supply voltage lines (VDD, VSNSext); a switch driver circuit (211, 213) configured to drive the switching transistors (211, 213) with first and second respective control signals of opposing phases; an output connection (ANTP) for driving an output load; and wherein the low side split gate-source switching transistor comprises a first power transistor and a second current sense transistor, each having a drain node directly connected to the output connection (ANTP) and a gate node driven by a shared gate control signal, wherein a source node of the first power transistor is connected to the second power supply line (VSNSext);wherein the switching amplifier further comprises an output current sensing circuit for measuring a current through the output load with a current sensing resistor (Rs) having a first node (VSNSresn) connected to the second supply voltage line (VSNSext) and a second node (VSNSresp) connected to a source of the second current sense transistor in the low side split gate-source switching transistor; wherein the low side split gate-source switching transistor further comprises a third current sense transistor having a drain node directly connected to the output connection (ANTP) and source node connected to the second node (VSNSresp) of the current sensing resistor (Rs), where a gate node of the third current sense transistor is connected by a connection switch to the shared gate control signal in a first connection state, and is connected by the connection switch to the source node of the third current sense transistor in a second connection state so that less current is provided to the current sensing resistor (Rs) in the second state than in the first state; and wherein the first power transistor is larger in size than the second current sense transistor and the third current sense transistor; wherein the high-side split gate-source transistor defines a plurality of constituent transistors (201A, 201B, 201C, 201D) having a shared drain terminal connected to the first supply voltage line with separate gate terminals each connected to the output of the switch driver circuit and source terminals connected to the output connection (ANTP). an output driving circuit comprising a high side split gate-source switching transistor and low side split gate-source switching transistor connected in series between first and second supply voltage lines (VDD, VSNSext); a switch driver circuit (211, 213) configured to drive the switching transistors (211, 213) with first and second respective control signals of opposing phases; an output connection (ANTP) for driving an output load; and wherein the low side split gate-source switching transistor comprises a first power transistor and a second current sense transistor, each having a drain node directly connected to the output connection (ANTP) and a gate node driven by a shared gate control signal, wherein a source node of the first power transistor is connected to the second power supply line (VSNSext);wherein the switching amplifier further comprises an output current sensing circuit for measuring a current through the output load with a current sensing resistor (Rs) having a first node (VSNSresn) connected to the second supply voltage line (VSNSext) and a second node (VSNSresp) connected to a source of the second current sense transistor in the low side split gate-source switching transistor; wherein the low side split gate-source switching transistor further comprises a third current sense transistor having a drain node directly connected to the output connection (ANTP) and source node connected to the second node (VSNSresp) of the current sensing resistor (Rs), where a gate node of the third current sense transistor is connected by a connection switch to the shared gate control signal in a first connection state, and is connected by the connection switch to the source node of the third current sense transistor in a second connection state so that less current is provided to the current sensing resistor (Rs) in the second state than in the first state; and wherein the first power transistor is larger in size than the second current sense transistor and the third current sense transistor; wherein the high-side split gate-source transistor defines a plurality of constituent transistors (201A, 201B, 201C, 201D) having a shared drain terminal connected to the first supply voltage line with separate gate terminals each connected to the output of the switch driver circuit and source terminals connected to the output connection (ANTP).