Capacitive DC-to-DC converter with efficient use of flying capacitors and related method

An implantable medical device comprising:

• a sensor adapted to be coupled to living tissue;
• a monitor circuit coupled to said sensor for processing inputs received from said sensor and powered with an output power supply voltage;
• a power source;
• and
• a DC-to-DC converter having an input coupled to said power source and an output coupled to said monitor circuit for providing said output power supply voltage thereto, comprising:
• N capacitors, wherein N is a whole number greater than one;
• and
• a controller coupled to each of said N capacitors and to an output voltage terminal for providing said output power supply voltage thereto, and having N+1 phases wherein:
• during a first phase of said N+1 phases said controller couples selected ones of said N capacitors to said output voltage terminal;
• during successive N phases of said N+1 phases said controller couples other selected ones of said N capacitors selectively between an input voltage terminal, said output voltage terminal, and a power supply voltage terminal, such that voltages across each capacitor of said N capacitors and at said output voltage terminal assume respective uniquely determined values during all of said N+1 phases.

A method for converting an input voltage to an output voltage comprising the steps of:

• providing N capacitors wherein N is a whole number greater than one;
• generating at least N+1 phases;
• coupling selected ones of said N capacitors to an output voltage terminal during a first phase;
• and
• coupling other selected ones of said N capacitors selectively between an input voltage terminal, said output voltage terminal, and a power supply voltage terminal during each remaining phase such that voltages across each capacitor of said N capacitors and the output voltage assume respective uniquely determined values during all of said N+1 phases.