High-efficiency DC/DC voltage converter including capacitive switching pre-converter and down inductive switching post-regulator

• US 20090059630A1
• Filed: 08/08/2007
• Published: 03/05/2009
• Est. Priority Date: 12/30/2006
• Status: Active Grant

• Current Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Inventors: Williams, Richard K.
• Granted Patent: US 7,777,459 B2
• Time in Patent Office: Days
• US Class Current: 363/60
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/0095 Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A DC/DC converter includes a pre-converter stage, which may include a charge pump, and a post-regulator stage, which may include a Buck converter. The duty factor of the post-regulator stage is controlled by a feedback path that extends from the output terminal of the DC/DC converter to an input terminal in the post-regulator stage. The pre-converter steps the input DC voltage up or down by a positive or negative integral or fractional value, and the post-regulator steps the voltage down by a variable amount depending on the duty factor at which the post-regulator is driven. The converter overcomes the problems of noise glitches, poor regulation, and instability, even near unity input-to-output voltage conversion ratios.

Claims

1. A DC/DC voltage converter comprising:

a pre-converter comprising a switched capacitive circuit; and

a post-regulator comprising a switched inductive circuit;

wherein an output terminal of the pre-converter is coupled to an input terminal of the post-regulator, an input terminal of the pre-converter comprising an input terminal of the DC/DC voltage converter, an output terminal of the post-regulator comprising an output terminal of the DC/DC voltage converter

and wherein the post-regulator is adapted to produce a voltage at the output terminal of the post-regulator that is lower in absolute value than a voltage at the input terminal of the post-regulator.

2. The DC/DC voltage converter of claim 1 further comprising a feedback path, a first terminal of the feedback path being coupled to the pre-converter, a second terminal of the feedback path being coupled to the output terminal of the post-regulator.

4. The DC/DC voltage converter of claim 1 wherein the post-regulator comprises a high-side switch connected in a series path with a low-side switch and an inductor connected to a point in the series path between the high-side switch and the low-side switch, the series path extending from the input terminal of the post-regulator.

5. The DC/DC voltage converter of claim 4 wherein the high-side switch comprises a high-side MOSFET and the low-side switch comprises a low-side MOSFET.

6. The DC/DC voltage converter of claim 5 wherein the post-regulator comprises a break-before-make unit coupled to a gate of the high-side MOSFET and a gate of the low-side MOSFET.

7. The DC/DC voltage converter of claim 6 wherein the post-regulator comprises a pulse width modulation unit coupled to the break-before-make unit and a clock generator coupled to the pulse width modulation unit.

9. The DC/DC voltage converter of claim 7 wherein the clock generator is coupled to the pre-converter.

10. The DC/DC voltage converter of claim 7 comprising a level shift unit coupled to the pulse width modulation unit.

11. The DC/DC voltage converter of claim 10 comprising a feedback path, a first terminal of the feedback path being coupled to the level shift unit.

12. The DC/DC voltage converter of claim 11 wherein a second terminal of the feedback path is coupled to the output terminal of the post-regulator.

13. The DC/DC voltage converter of claim 1 wherein the pre-converter comprises a charge pump, the charge pump producing an output voltage equal to a predetermined multiple of an input voltage.

14. The DC/DC voltage converter of claim 13 wherein the predetermined multiple is a fraction less than one.

15. The DC/DC voltage converter of claim 14 wherein the charge pump produces an output voltage equal to 0.5 times the input voltage.

16. The DC/DC voltage converter of claim 15 wherein the post-regulator comprises a Buck converter.

17. The DC/DC voltage converter of claim 16 wherein the post-regulator comprises a high-side switch connected in a series path with a low-side switch and an inductor connected to a point in the series path between the high-side switch and the low-side switch, the series path extending from the input terminal of the post-regulator.

18. The DC/DC voltage converter of claim 13 wherein the predetermined multiple is a number greater than one.

19. The DC/DC voltage converter of claim 18 wherein the charge pump produces an output voltage equal to 2 times the input voltage.

20. The DC/DC voltage converter of claim 19 wherein the post-regulator comprises a Buck converter.

21. The DC/DC voltage converter of claim 20 wherein the post-regulator comprises a high-side switch connected in a series path with a low-side switch and an inductor connected to a point in the series path between the high-side switch and the low-side switch, the series path extending from the input terminal of the post-regulator.

22. The DC/DC voltage converter of claim 18 wherein the charge pump produces an output voltage equal to 1.5 times the input voltage.

23. The DC/DC voltage converter of claim 22 wherein the post-regulator comprises a boost converter.

24. The DC/DC voltage converter of claim 23 wherein the post-regulator comprises a high-side switch connected in a series path with a low-side switch and an inductor connected to a point in the series path between the high-side switch and the low-side switch, the series path extending from the input terminal of the post-regulator.

25. The DC/DC voltage converter of claim 13 wherein the predetermined multiple is a negative number.

26. The DC/DC voltage converter of claim 25 wherein the charge pump produces an inverted output voltage equal to −

1 times the input voltage.

27. The DC/DC voltage converter of claim 25 wherein the charge pump produces an inverted output voltage equal to −

0.5 times the input voltage.

3. (canceled)

8. (canceled)