Power converter with reduced RMS input current

Patent metadata

Field	Value
Publication number	US-11228243-B2
Application number	US-202016900669-A
Country	US
Kind code	B2
Filing date	Jun 12, 2020
Priority date	Jun 12, 2020
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A power converter includes a first flying capacitor, an inductor, and a driver. A network of switches has a first switch to couple the first flying capacitor to a first port, and a second switch to couple the inductor to ground. The driver is adapted to drive the network of switches with a sequence of states that includes a first state and a second state. In the first state the ground port is coupled to a second port via a first path comprising the first flying capacitor and the inductor, and the first port is decoupled from the second port. In the second state the ground port is coupled to second port via a second path comprising the second switch and the inductor, and the first port is coupled to the second port via a third path comprising the first flying capacitor while bypassing the inductor.

First claim

What is claimed is:

1. A power converter for providing an output voltage with a target conversion ratio, the power converter having a ground port, a first port, and a second port, wherein when the power converter operates as a step-down converter the first port receives an input voltage and the second port provides the output voltage and when the power converter operates as a step-up converter the second port receives an input voltage and the first port provides the output voltage; the power converter comprising
a first flying capacitor coupled to a network of switches,
an inductor coupled to the second port, and
a driver;

the network of switches comprising
a first switch to couple the first flying capacitor to the first port;
a second switch to couple the inductor to ground;
the driver being adapted to drive the network of switches with a sequence of states during a drive period, the sequence of states comprising a first state and a second state,
wherein in the first state the ground port is coupled to the second port via a first path comprising the first flying capacitor and the inductor, and the first port is decoupled from the second port,
wherein in the second state the ground port is coupled to the second port via a second path comprising the second switch and the inductor, and wherein the first port is coupled to the second port via a third path comprising the first flying capacitor while bypassing the inductor.

2. The power converter as claimed in claim 1 , further comprising a second flying capacitor coupled to the second port via a first inductor switch, wherein the network of switches comprises a capacitor switch between the first flying capacitor and the second flying capacitor.

3. The power converter as claimed in claim 2 , wherein in the first state the first path comprises the first flying capacitor, the capacitor switch, the second flying capacitor and the inductor, and wherein in the second state the ground port is coupled to the second port via a ground path comprising the second switch, the second flying capacitor and the first inductor switch, while bypassing the inductor.

4. The power converter as claimed in claim 2 , wherein the network of switches comprises a second capacitor switch between the first flying capacitor and the second flying capacitor, and a ground switch to couple the second flying capacitor to the ground.

5. The power converter as claimed in claim 4 , wherein the inductor is coupled to the first flying capacitor via a second inductor switch, and wherein the first flying capacitor is coupled to the second port via a third capacitor switch.

6. The power converter as claimed in claim 5 , wherein in the first state the ground port is coupled to the second port via another path comprising the ground switch, the second flying capacitor, the first inductor switch and the inductor; and wherein in the second state the first port is coupled to the second port via a path comprising the capacitor switch, the second flying capacitor, the second capacitor switch, the first flying capacitor and the third capacitor switch, while bypassing the inductor.

7. The power converter as claimed in claim 2 , further comprising a third flying capacitor, the third flying capacitor having a first terminal coupled to the first flying capacitor via a first coupling switch, and a second terminal coupled to the first flying capacitor via a second coupling switch.

8. The power converter as claimed in claim 7 , wherein the driving sequence comprises a primary first-state, a secondary first-state, a primary second-state and a secondary second-state.

9. The power converter as claimed in claim 8 , wherein in the primary second-state the ground port is coupled to the second port via a first ground path comprising the second flying capacitor while bypassing the inductor, and wherein the first port is coupled to the second port via a path comprising the first and third flying capacitors while bypassing the inductor.

10. The power converter as claimed in claim 9 , wherein in the secondary second state the ground port is coupled to the second port via the first ground path, and a second ground path comprising the first and third flying capacitors while bypassing the inductor.

11. The power converter as claimed in claim 8 , wherein in the primary and secondary first states the ground port is coupled to the second port via a path comprising the first flying capacitor, the second flying capacitor and the inductor.

12. The power converter as claimed in claim 11 , wherein the driving sequence comprises a first additional state, and a second additional state, wherein in the first additional state the first port is coupled to the second port via a path comprising the second and third flying capacitors and the inductor, and wherein in the second additional state the ground port is coupled to the second port via a path comprising the second and third flying capacitors and the inductor.

13. The power converter as claimed in claim 1 , wherein the driving sequence comprises another first state in which the ground port is de-coupled from the second port and wherein the first port is coupled to the second port via a path comprising the inductor.

14. The power converter as claimed in claim 1 , further comprising a current sensor for sensing an inductor current through the inductor, wherein the driver is adapted to open the second switch during the second state upon sensing that the inductor current has reached a threshold value.

15. The power converter as claimed in claim 1 , wherein the power converter is a step-down converter, the first state being a magnetization state and the second state being a de-magnetization state.

16. The power converter as claimed in claim 1 , wherein the power converter is a step-up converter, the first state being a de-magnetization state and the second state being a magnetization state.

17. A method of converting power by providing an output voltage with a target conversion ratio, the method comprising
providing a power converter having a ground port, a first port, and a second port, wherein when the power converter operates as a step-down converter the first port receives an input voltage and the second port provides the output voltage and when the power converter operates as a step-up converter the second port receives an input voltage and the first port provides the output voltage; the power converter comprising a first flying capacitor coupled to a network of switches, an inductor coupled to the second port, and a driver; the network of switches comprising a first switch to couple the first flying capacitor to the first port; a second switch to couple the inductor to ground;
driving the network of switches with a sequence of states during a drive period, the sequence of states comprising a first state and a second state,
wherein in the first state the ground port is coupled to the second port via a first path comprising the first flying capacitor and the inductor, and the first port is decoupled from the second port,
wherein in the second state the ground port is coupled to the second port via a second path comprising the second switch and the inductor, and wherein the first port is coupled to the second port via a third path comprising the first flying capacitor while bypassing the inductor.

Assignees

• Dialog Semiconductor Uk Ltd

Inventors

• Petersen Holger

Classifications

• H02M1/0095 Primary

  Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck · CPC title

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M3/155

  using semiconductor devices only · CPC title

• H02M1/088

  for the simultaneous control of series or parallel connected semiconductor devices · CPC title