Hybrid power supply

5 The hybrid power supply of claim 1 wherein the primary battery is an alkaline cell, Zn-air cell, fuel cell, solar cell, or another current limited power source.

6 The hybrid power supply of claim 1 wherein the rechargeable battery is a Li-Ion or Li-Polymer rechargeable cell.

7 The hybrid power supply of claim 1 wherein the primary battery control comprises:

• operational amplifier with a primary battery current sensing resistor to provide primary battery current control, having the output of the amplifier coupled to the closed feedback loop of the converter.

The hybrid power supply of claim 9 wherein the closed feedback loop of the converter further comprises:

• a resistor coupled between output and feedback terminals of the converter.

A hybrid power supply comprises:

• a switching type DC/DC boost type converter that receives energy from a primary cell and is arranged to deliver the energy to a rechargeable cell;
• a circuit disposed to control the switching type DC/DC converter, the circuit comprising:
• a resistor voltage divider coupled to the feedback input of the converter, selected to provide a fixed output voltage that is less than the full charge voltage of the rechargeable cell.

The hybrid power supply of claim 12 wherein the primary cell is an alkaline cell, Zn-air cell, fuel cell or solar cell, or another current limited power source.

14 The hybrid power supply of claim 15 wherein the circuit delivers an output voltage that corresponds to about 90% charge of the rechargeable cell.

15 A method of operating a hybrid power supply comprises:

• delivering energy from a primary cell to a rechargeable cell through a switching type DC/DC boost type converter at a fixed voltage that is less than the full charge voltage of the rechargeable cell.

The method of claim 15, further comprising:

• controlling a circuit that senses primary battery current, and controls in part operation of the converter to provide a constant current discharge on the primary battery side of the hybrid power supply.

The method of claim 15 wherein the primary cell is an alkaline cell, Zn-air cell, fuel cell or solar cell, or another current limited power source.

The method of claim 15 wherein the rechargeable cell is Li-Ion or Li-Polymer rechargeable cell.

19 The method of claim 15 wherein the circuit delivers an output voltage that corresponds to about 90% charge of the rechargeable cell.