High efficiency power regulator and method

1. A system comprising:

a three-terminal converter comprising:

a first terminal coupled to an input voltage bus;

a second terminal coupled to an output voltage bus; and

a third terminal coupled to a first terminal of a protection device; and

the protection device, wherein a portion of an output current of the output voltage bus is configured to flow through the protection device, and wherein the portion of the output current is equal to a current flowing through a power switch of the three-terminal converter.

2. The system of claim 1 , wherein the protection device comprises:

an inrush current limiting element; and

a reverse polarity protection element.

3. The system of claim 2 , wherein:

the inrush current limiting element is connected in series with the reverse polarity protection element.

4. The system of claim 2 , wherein:

the inrush current limiting element is an n-type metal oxide semiconductor (NMOS) transistor.

5. The system of claim 2 , wherein:

the inrush current limiting element is a p-type metal oxide semiconductor (PMOS) transistor.

6. The system of claim 2 , wherein:

the reverse polarity protection element is an NMOS transistor.

7. The system of claim 2 , wherein:

the reverse polarity protection element is a PMOS transistor.

8. The system of claim 2 , wherein:

the reverse polarity protection element is a diode.

9. The system of claim 1 , wherein:

the three-terminal converter is a buck dc-dc converter.

10. The system of claim 1 , wherein:

the three-terminal converter is a boost dc-dc converter.

11. The system of claim 1 , wherein:

the three-terminal converter is a buck-boost dc-dc converter.

12. The system of claim 1 , wherein:

the three-terminal converter is a dc-dc converter configured to operate with negative power, the system comprising:

the protection device coupled between a common return of the input voltage bus and the output voltage bus, and an intermediate point; and

the dc-dc converter comprising:

the first terminal coupled to a negative terminal of the input voltage bus;

the second terminal coupled to a negative terminal of the output voltage bus; and

the third terminal coupled to the intermediate point.

13. The system of claim 1 , wherein:

the three-terminal converter is a dc-dc converter configured to operate with positive power, the system comprising:

the protection device coupled between a common return of the input voltage bus and the output voltage bus, and an intermediate point; and

the dc-dc converter comprising:

the first terminal coupled to a positive terminal of the input voltage bus;

the second terminal coupled to a positive terminal of the output voltage bus; and

the third terminal coupled to the intermediate point.

14. A regulator comprising:

a first switching element;

an input capacitor coupled between a positive terminal of an input voltage bus and a return point;

an output capacitor coupled between a positive terminal of an output voltage bus and the return point; and

a protection device coupled between the return point and a common return point of the input voltage bus and the output voltage bus, wherein a portion of an output current of the output voltage bus is configured to flow through the protection device, and wherein the portion of the output current is equal to a current flowing through a power switch of the regulator.

15. The regulator of claim 14 , further comprising a second switching element and an inductor, wherein:

the first switching element is coupled between the positive terminal of the input voltage bus and a phase point of the regulator;

the second switching element is coupled between the phase point of the regulator and the return point; and

the inductor is coupled between the phase point of the regulator and the positive terminal the output voltage bus.

16. The regulator of claim 14 , further comprising a second switching element and an inductor, wherein:

the inductor is coupled between the positive terminal the input voltage bus and a phase point of the regulator;

the first switching element is coupled between the positive terminal of the output voltage bus and the phase point of the regulator; and

the second switching element is coupled between the phase point of the regulator and the return point.

17. The regulator of claim 14 , further comprising a second switching element, a third switching element, a fourth switching element and an inductor, wherein:

the first switching element is coupled between the positive terminal of the input voltage bus and a first phase point of the regulator;

the second switching element is coupled between the first phase point of the regulator and the return point;

the inductor is coupled between the first phase point and a second phase point;

the third switching element is coupled between the second phase point of the regulator and the return point; and

the fourth switching element is coupled between the positive terminal of the output voltage bus and the second phase point of the regulator.

18. A method comprising:

connecting a first terminal of a three-terminal converter to a positive terminal of an input voltage bus;

connecting a second terminal of the three-terminal converter to a positive terminal of an output voltage bus;

connecting a third terminal of the three-terminal converter to a first terminal of a protection device, wherein a portion of an output current of the output voltage bus is configured to flow through the protection device, and wherein the portion of the output current is equal to a current flowing through a power switch of the three-terminal converter; and

connecting a second terminal of the protection device to a common return of the input voltage bus and the output voltage bus.

19. The method of claim 18 , further comprising:

connecting an inrush current limiting device between the first terminal of the protection device and a junction point of the protection device; and

connecting a reverse polarity protection device between the junction point and the second terminal of the protection device.

20. The method of claim 19 , wherein the inrush current limiting is a first n-type metal oxide semiconductor (NMOS) transistor, the method further comprising:

configuring a gate voltage of the first NMOS transistor such that:

the first NMOS transistor is slowly turned on when a surge voltage is applied to the input voltage bus; and

the first NMOS transistor is fully turned on when a steady voltage is applied to the input voltage bus.

21. The method of claim 19 , wherein the reverse polarity protection device is a second NMOS transistor, the method further comprising:

configuring a gate voltage of the second NMOS transistor such that:

the second NMOS transistor allows a current to flow through the second NMOS transistor when a positive lead of the three-terminal converter is coupled to a positive terminal the input voltage; and

the second NMOS transistor prevents a current from flowing through the second NMOS transistor when a positive lead of the three-terminal converter is coupled to a negative terminal the input voltage.

22. The method of claim 18 , further comprising:

configuring the three-terminal converter such that the three-terminal converter operates in a high duty cycle mode.