Patent ID: 8154258

Claim:
An energy storage module comprising: one or more capacitor banks, each including one or more capacitors, wherein the one or more capacitors includes a first capacitor and a second capacitor connected in series for storing energy, wherein a first terminal of the first capacitor is coupled to a first terminal of the second capacitor at a node, and a second terminal of the first capacitor is coupled to a circuit ground node, and a second terminal of the second capacitor is coupled to a regulated direct current (DC) voltage through a first resistor; a first voltage regulator coupled to the one or more capacitor banks and configured to, during a normal mode of operation, provide the regulated DC voltage to charge the one or more capacitors of each of the capacitor banks; wherein each of the one or more capacitor banks includes a voltage leveling circuit coupled to the one or more capacitors and configured to maintain a specific voltage on each of the one or more capacitors, wherein the voltage leveling circuit includes: a passive leveling portion having a first bleed resistor coupled between the node between the first and second capacitors and circuit ground, and a second bleed resistor coupled between the second terminal of the second capacitor and circuit ground; and an active leveling portion including: a second voltage regulator circuit coupled to the node between the first and second capacitors and configured to actively provide a first specific voltage to the node between the first and second capacitors; and a third capacitor coupled in parallel with a control resistor between circuit ground and a control input of the second voltage regulator; and an output circuit coupled to each of the one or more capacitor banks and configured to, during a backup mode of operation, provide an output voltage derived from an output of each of the one or more capacitor banks, wherein the output circuit includes a control unit configured to regulate and combine the output of each of the one or more capacitor banks.