Power supply providing ultrafast modulation of output voltage

• US 20070024360A1
• Filed: 07/27/2005
• Published: 02/01/2007
• Est. Priority Date: 07/27/2005
• Status: Active Grant

• Current Assignee: Artesyn Technologies Incorporated (Artesyn Embedded Technologies, Inc.)
• Original Assignee: Artesyn Technologies Incorporated (Artesyn Embedded Technologies, Inc.)
• Inventors: Markowski, Piotr
• Granted Patent: US 7,602,155 B2
• Time in Patent Office: Days
• US Class Current: 330/123
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/0238 using supply converters
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/195 A hybrid coupler being used as power measuring circuit at the input of an amplifier circuit
• CPC Class Codes: H03F 2200/207 A hybrid coupler being used as power measuring circuit at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/504 the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
• CPC Class Codes: H03F 3/2178 using more than one switch or switching amplifier in parallel or in series H03F3/2173, H03F3/2175 take precedence

Abstract

A power supply for providing a modulated output voltage to a load is disclosed. According to various embodiments, the power supply comprises a plurality of parallel-connected switch-mode power modules and a controller. The controller is connected to each of the power modules and is for controlling the duty cycles of the respective power modules such that the power modules have a common duty cycle in steady state, but in a phase-shifted or “interleaved” manner. In addition, the controller is for controlling the output voltage of the power converter by controlling the ratio of power modules in the forward state at a time to the total number of power modules. In this way, by providing a sufficiently large number of power modules, arbitrarily low output voltage amplitudes and intra-level oscillations can be achieved. Further, the rate of modulation of the output voltage can exceed the switching frequency (f=1/T, where T is the switching period) of the power modules. An rf power amplifier system including such a power supply is also disclosed.

Claims

1. A power supply for providing a modulated output voltage to a load comprising:

a plurality of parallel-connected switch-mode power modules; and

a controller connected to each of the power modules for controlling the duty cycles of the power modules, wherein the controller is for controlling the power modules such that the power modules have a common duty cycle in steady state, and wherein the controller is for controlling the output voltage of the power converter by controlling the ratio of power modules in the forward state at a time to the total number of power modules.

2. The power supply of claim 1, wherein the controller is for controlling the duty cycle of each power module by outputting a PWM control signal to each power module, and wherein:

the period (T) of each PWM control signal is the same; and

the respective PWM control signals are shifted in phase relative to each other by T/N, where N is the number of power modules.

3. The power supply of claim 2, wherein the rate of modulation of the output voltage exceeds the switching frequency of the power modules.

4. The power supply of claim 2, wherein the power modules do not include a discrete output filter capacitor.

5. The power supply of claim 4, wherein each power module comprises a buck converter.

6. The power supply of claim 5, wherein each power module comprises a synchronous buck converter.

7. The power supply of claim 4, wherein each power modules comprises a voltage-fed power converter.

8. The power supply of claim 4, wherein each power module comprises a boost converter.

9. The power supply of claim 4, wherein each power module comprises a buck-boost converter.

10. A power amplifier system comprising:

a power amplifier for amplifying an input rf signal; and

a power supply connected to the power amplifier for supplying a supply voltage to the power amplifier, wherein the power supply comprises;

a plurality of parallel-connected switch-mode power modules; and

a controller connected to each of the power modules for controlling the duty cycles of the power modules, wherein the controller is for controlling the power modules such that the power modules have a common duty cycle in steady state, and wherein the controller is for controlling the output voltage of the power converter by controlling the ratio of power modules in the forward state at a time to the total number of power modules.

11. The power amplifier system of claim 10, wherein the controller of the power supply is for controlling the duty cycle of each power module by outputting a PWM control signal to each power module, and wherein:

the period (T) of each PWM control signal is the same; and

the respective PWM control signals are shifted in phase relative to each other by T/N, where N is the number of power modules.

12. The power amplifier system of claim 11, wherein the rate of modulation of the output voltage of the power supply exceeds the switching frequency of the power modules.

13. The power amplifier system of claim 11, wherein the power modules do not include a discrete output filter capacitor.

14. The power amplifier system of claim 11, wherein the power supply includes an open-loop power supply.

15. The power amplifier system of claim 14, further comprising a delay modification circuit in communication with the power supply for adjusting the delay of the power supply.

16. The power amplifier system of claim 14, further comprising a second, closed-loop regulator connected in parallel with the open-loop power supply for additionally supplying supply voltage to the power amplifier.

17. The power amplifier system of claim 16, wherein the second regulator includes a linear regulator.

18. The power amplifier system of claim 16, wherein the second regulator includes a switching regulator having a switching frequency greater than the switching frequency of the open-loop power supply.

19. The power amplifier system of claim 16, further comprising a delay modification circuit in communication with the open-loop power supply for adjusting the delay of the open-loop power supply.

20. The power amplifier system of claim 19, wherein the second regulator includes a linear regulator.

21. The power amplifier system of claim 19, wherein the second regulator includes a switching regulator having a switching frequency greater than the switching frequency of the open-loop power supply.

22. The power amplifier system of claim 11, wherein the power supply includes a closed-loop power supply.

23. A power amplifier system comprising:

a power amplifier for amplifying an input rf signal;

an open-loop switching regulator; and

a closed-loop regulator connected in parallel with the open-loop switching regulator such that the parallel combination of the open-loop switching regulator and the close-loop regulator supply a supply voltage to the power amplifier.

24. The power amplifier system of claim 23, further comprising a delay modification circuit in communication with the open-loop switching regulator for adjusting the delay of the open-loop switching regulator.

25. The power amplifier system of claim 24, wherein the closed-loop regulator includes a linear regulator.

26. The power amplifier system of claim 24, wherein the closed-loop regulator includes a switching regulator having a switching frequency greater than the switching frequency of the open-loop switching regulator.