An apparatus for supplying power to a load. The apparatus including a plurality of sources to provide charge, and a controller adapted to control a transfer of charge from the sources to the load at distinct times. The controller may control the transfer of charge based on variation of an ambient condition or a manufacturing process. The controller may control the transfer of charge to generate a defined voltage across the load. The apparatus may include a regulator adapted to regulate a voltage across the load. The regulator may regulate the voltage across the load in a defined timing relationship with the transfer of charge from the sources to the load.