Electrical power energy converter unit for converting direct current to direct current, DC-DC, with maximum power point tracking, MPPT, to get the highest possible efficiency

1. An electrical power energy converter unit for converting Direct Current to Direct Current (DC-DC), comprising:

a DC-DC converting module operable for connecting with an energy harvesting module, supplying an electrical input for the DC-DC converting module, and outputting an electrical output for connecting a load;

a controller module operable for electrically controlling the DC-DC converting module and controlling electrical parameters thereof, wherein the electrical parameters comprise at least an input impedance of the DC-DC converting module; and

a maximum power point tracking module, coupled with the controller module, operable for outputting a power point control signal to the controller module for adjusting at least one of the electrical parameters, wherein the maximum power point tracking module comprises a resistor connected in series with the electrical output for connecting the load of the DC-DC converting module and providing the power point control signal to the controller module upon a comparison between a first and second voltage potential sample over the resistor, and wherein the first and second voltage potential are sampled sequentially in time.

2. The electrical power energy converter unit according to claim 1 , wherein the electrical power energy converter unit is operable for subsequently turning on and off the maximum power point tracking module.

3. The electrical power energy converter unit according to claim 1 , wherein the electrical power energy converter unit is operable for subsequently turning on and off the current to the resistor.

4. The electrical power energy converter unit according to claim 2 , wherein the electrical power energy converter unit is operable for simultaneously turning on and off the maximum power point tracking module and the current to the resistor.

5. The electrical power energy converter unit according to claim 3 , wherein the maximum power point tracking module further comprises a bypass circuit for bypassing the resistor wherein current to the resistor is turned off.

6. The electrical power energy converter unit according to claim 1 , further comprising a duty cycle of turning one or more of the current to the resistor on and off, and turning the maximum power point tracking module on and off, that is at most 50%.

7. The electrical power energy converter unit according to claim 1 , wherein the output current of the DC-DC converting module is measured by determining the first and second voltage potential sample over the resistor.

8. The electrical power energy converter unit according to claim 1 , wherein the DC-DC converting module is a switched capacitor DC-DC converter.

9. The electrical power energy converter unit according to claim 1 , wherein the resistor is an adjustable resistor or a programmable resistor.

10. The electrical power energy converter unit according to claim 1 , wherein the resistor is a fraction of the output resistance of the DC-DC converting module.

11. The electrical power energy converter unit according to claim 1 , wherein the controller comprises an oscillator.

12. The electrical power energy converter unit according to claim 1 , wherein the electrical parameters further comprise one or more of voltage gain and switching frequency of the DC-DC converting module.

13. The electrical power energy converter unit according to claim 1 , wherein the voltage drop between the first and second voltage potential is amplified by a voltage amplifier.

14. The electrical power energy converter unit according to claim 13 , wherein the voltage amplifier is a switched capacitor amplifier.

15. The electrical power energy converter unit according to claim 14 , wherein the maximum power point tracking module further comprises a low-pass filter for smoothing at least one of the first and second voltage potential signal.

16. The electrical power energy converter unit according to claim 1 , wherein the maximum power point tracking module further comprises a sample-and-hold comparator for sequentially sampling the first and second voltage potential in time.

17. The electrical power energy converter unit according to claim 1 , wherein the maximum power point tracking module further comprises a state machine for determining that one or more of the electrical parameters have to be changed.

18. The electrical power energy converter unit according to claim 17 , wherein the state machine determines to adapt the bit count of one or both of the controller module and the DC-DC converting module.

19. A System-on-a-Chip (SoC) comprising the electrical power energy converter unit according to claim 1 .