Voltage regulation of a DC/DC converter

1. Power system comprising

a plurality of power sources, each of the plurality of power sources being a same type of power source;

a separate capacitor connected in parallel with each of the plurality of power sources; and

a DC/DC converter comprising

a separate input coupled to each of the plurality of power sources,

a separate input voltage regulation circuit coupled to each of the separate inputs, wherein each input voltage regulation circuit comprises

a comparator configured to compare a voltage of the separate input with a reference voltage; and

a switch comprising a transistor coupled in parallel with a diode, wherein the switch is coupled to receive an output of the comparator;

a charge pump coupled to the separate input and arranged to augment a voltage received from the separate input and to provide the augmented voltage to the comparator as a power supply of the comparator; and

an output of the DC/DC converter, wherein the output of the DC/DC converter is coupled to the switch of each separate input voltage regulation circuit and coupled to a load for allowing power transfer from the plurality of power sources to the load.

2. Power system according to claim 1 , wherein the plurality of power sources are solar cells.

3. Power system according to claim 1 , wherein each voltage regulation controller is configured to regulate the input voltage of one of the plurality of power sources based on levels of illumination by ambient light.

4. Power system according to claim 1 , wherein the plurality of power sources are thermoelectric generators.

5. Power system according to claim 1 , wherein each voltage regulation controller is configured to regulate the input voltage of one of the plurality of power sources based on temperature gradient between hot and cold sources and absolute temperature values for hot and cold sources.

6. Power system according to claim 1 , wherein the load comprises a battery and/or an electronic function.

7. User equipment comprising:

a load;

a plurality of power sources, each of the plurality of power sources being a same type of power source;

a separate capacitor connected in parallel with each of the plurality of power sources; and

a DC/DC converter comprising

a separate input coupled to each of the plurality of power sources,

a separate input voltage regulation circuit coupled to each of the separate inputs, wherein each input voltage regulation circuit comprises

a comparator configured to compare a voltage of the separate input with a reference voltage; and

a switch comprising a transistor coupled in parallel with a diode, wherein the switch is coupled to receive an output of the comparator;

a charge pump coupled to the separate input and arranged to augment a voltage received from the separate input and to provide the augmented voltage to the comparator as a power supply of the comparator; and

an output of the DC/DC converter, wherein the output of the DC/DC converter is coupled to the switch of each separate input voltage regulation circuit and coupled to the load for allowing power transfer from the plurality of power sources to the load.

8. Power system according to claim 2 , wherein each voltage regulation controller is configured to regulate the input voltage of one of the plurality of power sources based on levels of illumination by ambient light.

9. Power system according to claim 4 , wherein each voltage regulation controller is configured to regulate the input voltage of one of the plurality of power sources based on temperature gradient between hot and cold sources and absolute temperature values for hot and cold sources.

10. Power system according to claim 1 , wherein each of the plurality of power sources is connected in parallel with the other of the plurality of power sources.

11. User equipment according to claim 7 , wherein each of the plurality of power sources is connected in parallel with the other of the plurality of power sources.