Wireless neuromodulation systems

An external control unit (ECU) for use with an electrostimulator implant that comprises a receiving coil and is implantable in a subject, the ECU comprising:

• (i) a housing;
• (ii) a battery coupled to the housing;
• (iii) an antenna circuit, comprising a transmitting coil;
• (iv) a power unit, comprising:
• (a) a power amplifier, which is arranged to provide current to the antenna circuit;
• (b) first and second parallel current paths, which are arranged to convey power from the battery to the power amplifier;
• and
• (c) a storage capacitor, connected to the first parallel current path and not to the second parallel current path;
• and
• (v) a microcontroller, which is configured to:
• transmit power to the electrostimulator implant in a plurality of stimulation pulse trains, by activating the power unit to provide the current to the transmitting coil of the antenna circuit to induce an induced current in the receiving coil, wherein each of the stimulation pulse trains includes a stimulation period and one or more non-stimulation periods,
• drive the power unit to charge the storage capacitor with the power from the battery at least at one or more times other than during the stimulation period of each of the stimulation pulse trains,
• during the one or more non-stimulation periods of each of the stimulation pulse trains, drive the power unit to provide the power from the battery to the power amplifier via the second parallel current path and not via the first parallel current path, and
• during the stimulation period of each of the stimulation pulse trains, drive the power unit to provide power from the storage capacitor to the power amplifier via the first parallel current path and not via the second parallel current path.