Apparatus and methods configured to perform power regulation for an implantable device are presented. In an aspect, an implantable device can include a substrate that forms at least part of a body of the implantable device and a circuit disposed on or within the substrate. The circuit can include a high load power regulator configured to provide a first current level to components of the implantable device and a low load power regulator configured to provide a second current level to components of the implantable device, wherein the second current level is lower that the first current level. The circuit can also include a regulator switch configured to enable or disable current draw from the high load power regulator and the low load power regulator as a function of power state and associated power requirement of the components of the implantable device.