Method and apparatus for power management

A power management system comprising:

• a thermo-electric device;
• a low-voltage direct current to direct current voltage converter (DC-DC converter) coupled with the thermoelectric device;
• a high-efficiency DC-DC converter coupled with the thermoelectric device and the low-voltage DC-DC converter;
• a charge storage circuit coupled with the low-voltage DC-DC converter and the high-efficiency DC-DC converter;
• a voltage generation circuit coupled with the low-voltage DC-DC converter and the high-efficiency DC-DC converter, wherein the voltage generation circuit, in operation, disables the low-voltage DC-DC converter, and
• a programmable controller coupled with the charge storage circuit, the voltage generation circuit and the high-efficiency DC-DC converter, wherein the programmable controller substantially controls the operation of the charge storage circuit, the high-efficiency DC-DC converter and the voltage generation circuit.

A method comprising:

• generating a first voltage potential by converting thermal energy from a thermal energy source to electrical energy;
• converting the first voltage potential to a second voltage potential using a low-voltage direct current to direct current voltage converter (DC-DC converter) and storing the second voltage potential using a first charge storage device of a charge storage circuit;
• activating a controller circuit;
• converting the first voltage potential to a third voltage potential using the low-voltage DC-DC converter and storing the third voltage potential using the first charge storage device;
• setting an initial value for a variable time constant for charging a second charge storage device of the charge storage circuit;
• disabling the first DC-DC converter;
• and
• converting the first voltage potential to a fourth voltage potential using a high-efficiency DC-DC converter and storing the fourth voltage potential using the first and second charge storage devices, wherein storing the fourth voltage potential is based, at least in part, on the variable time constant.

A method of managing a thermally powered circuit comprising:

• converting a thermal voltage potential from a thermal voltage source to a power supply operating target voltage potential of a controller circuit using a low-voltage DC-DC converter to perform a first part of the conversion and a high-efficiency DC-DC converter to perform a second part of the conversion;
• opening a valve with a current supplied from the thermal voltage produced by the thermal voltage source;
• waiting a predetermined period of time;
• sensing an operating temperature of a gas valve coupled with the thermal voltage source;
• determining a target input voltage for holding the valve open based on the operating temperature;
• sensing an input voltage of the valve;
• comparing the input voltage with the target input voltage;
• and
• modifying a power conversion duty cycle of the high-efficiency DC-DC converter based on the comparison of the input voltage with the target input voltage.