Power supply
A power supply ( 1 ) for a load in the form of a PCMCIA card ( 2 ) has and onboard GPRS class (10) module (not shown). The module, and therefore card ( 2 ), demands a load current i load that has an average value over time and periodic instantaneous peak values (i peak ) that are significantly higher than the average value. Power supply ( 1 ) includes a pair of input terminals ( 3 ) for connecting with a power source in the form of a regulated power supply ( 4 ) that is contained within a personal computer (not shown). Supply ( 4 ) supplies a source current i input that is less than a predetermines current limit specified for the supply and which is less than the peak load current. A pair of output terminals ( 5 ) is electrically connected with terminals ( 3 ) and card ( 2 ). A supercapacitor device in the form of a single supercapacitor ( 6 ) is in parallel with terminals ( 3, 5 ) for allowing the load to be supplied the peak load current while maintaining the source current at less than the predetermined current limit.
1. A power supply for a load that demands an average load current and a peak load current that is higher than the average load current, the power supply including:
input terminals for connecting with a power source that supplies a source current that is less than a predetermined current limit, wherein the predetermined current limit is less than the peak load current;
output terminals for electrically connecting with the input terminals and the load; and
a supercapacitor device in parallel with the output terminals for allowing the load to be supplied to the peak load current while substantially maintaining the source current at less than about the predetermined current limit.
2. A supply according to claim 1 wherein the predetermined current limit is between the average load current and the peak load current.
3. A supply according to claim 1 wherein the voltage at the input terminals is greater than or equal to the voltage at the output terminals.
4. A supply according to claim 1 that maintains the input and the output terminals at substantially the same voltage.
5. A supply according to claim 1 wherein the supercapacitor device includes one or more supercapacitors in parallel with the output terminals.
6. A supply according to claim 1 including a current limiter disposed between the input terminals and the output terminals.
7. A supply according to claim 6 wherein the current limiter maintains the source current at less than the predetermined current limit during charging of the supercapacitive device from the power source.
8. A supply according to claim 1 wherein the supercapacitor device includes a plurality of supercapacitors that are connected in parallel with each other.
9. A supply according to claim 1 wherein the supercapacitor device includes a plurality of supercapacitors that are connected in series with each other.
10. A supply according to claim 1 wherein the supercapacitor device has an ESR of less than 30 mΩ.
11. A supply according to claim 10 wherein the supercapacitor device has an ESR of less than 24 mΩ.
12. A supply according to claim 11 wherein the supercapacitor device has an ESR of less than 20 mΩ.
13. A supply according to claim 1 wherein the supercapacitor device provides a capacitance of at least about 0.4 Farads.
14. A supply according to claim 1 wherein a footprint of the supercapacitor device is less than about 800 mm 2 .
15. A supply according to claim 1 , wherein the footprint of the supercapacitor device is less than about 40 mm×20 mm.