Supplying energy to an apparatus

An apparatus comprising:

• energy storage circuitry to store energy and to discharge some of the energy to supply the some of the energy to a processing circuit;
• discharge circuitry to further discharge the energy storage circuitry in response to the some of the energy being discharged to the processing circuit;
• power supply circuitry to recharge the energy storage circuitry,
• wherein
• the discharge circuitry is adapted to retain the non-zero residual energy in the energy storage circuitry when the energy storage circuitry is further discharged by the discharge circuitry during the supply of the some of the energy to the processing circuit;
• the discharge circuitry comprises a first transistor;
• the first transistor is a p-type transistor;
• the first transistor has a natural threshold operating voltage;
• and
• when the first transistor and other transistors are deactivated, the non-zero residual energy corresponds with the natural threshold operating voltage.