High efficiency power amplifier

• US 5,777,519 A
• Filed: 07/18/1996
• Issued: 07/07/1998
• Est. Priority Date: 07/18/1996
• Status: Expired due to Term

• Current Assignee: Anastasios V. Simopoulos
• Original Assignee: Anastasios V. Simopoulos
• Inventors: Simopoulos, Anastasios V.
• Primary Examiner(s): MOTTOLA, STEVEN J
• Application Number:
  US08/683,172
• Time in Patent Office: 719 Days
• Field of Search: 330/85, 330/136, 330/285, 330/297, 323/265, 323/266, 323/280
• US Class Current: 330/297
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence

Abstract

A high efficiency power amplifier system receives an unregulated voltage signal and an input signal V_in, and conditions the unregulated voltage signal to provide a regulated output signal whose magnitude depends on the value of the input signal V_in. The system includes a control circuit which detects changes in the input signal V_in and the regulated output signal, and provides a feedback signal to a variable output switching regulator, which controls the regulated output signal value to maintain a predetermined relationship between the input signal V_in and the regulated output signal. Significantly, controlling the regulated output signal such that it maintains the predetermined relationship with the input signal V_in allows the power amplifier system to provide the regulated voltage signal directly to the electrical load. The control circuit monitors V_in and the regulated output, and as either signal changes the control circuit provides the feedback control signal to the variable output switching regulator in order to drive V_out such that the predetermined relationship (e.g., V_out =constant*V_in) is maintained. Providing V_out in this manner substantially reduces the power dissipation of the power amplifier system.

Claims

1. A power amplifier system, comprising:

a variable output pulse modulated power supply which receives an unregulated voltage signal, and conditions and regulates said unregulated voltage signal to provide a regulated voltage signal value V_cc ;

an operational amplifier powered by said regulated voltage signal value V_cc and responsive to an input signal value V_in, for providing an output signal value V_out which is proportional to said input signal value V_in ;

a control circuit responsive to said regulated voltage signal value V_cc and said input signal value V_in for providing a feedback control signal; and

wherein, said variable output pulse modulated power supply receives said feedback control signal, and in response thereto drives said regulated voltage signal value V_cc to maintain the value (V_cc -V_out) equal to a predetermined value.

3. The power amplifier system of claim 1, wherein said variable output pulse modulated power supply includes a pulse width modulator.

4. The power amplifier system of claim 1, wherein said variable output pulse modulated power supply includes a pulse frequency modulator.

5. The power amplifier system of claim 1, wherein said variable output pulse modulated power supply includes a pulse phase modulator.

9. The power amplifier system of claim 1, wherein said input signal value V_in is unipolar.

10. The power amplifier system of claim 1, wherein said input signal value V_in is bipolar.

11. The variable output pulse modulated power supply of claim 1, wherein said variable output pulse modulated power supply includes

a pulse modulator which receives said feedback control signal and provides a drive signal;

a transformer comprising a primary winding and a secondary winding;

means responsive to said drive signal for switching an unregulated DC voltage signal across said primary winding to establish an AC signal in said secondary winding; and

a filter which rectifies said AC signal to provide said regulated voltage signal value V_cc.

12. The variable output pulse modulated power supply of claim 11, wherein said unregulated voltage signal is an AC signal, and said variable output pulse modulated power supply further comprises a diode bridge rectifier which receives said unregulated voltage signal and provides said unregulated DC voltage signal.

13. The variable output pulse modulated power supply of claim 1, wherein said unregulated voltage is a DC signal.

2. A power amplifier system, comprising:

a variable output pulse modulated power supply which receives an unregulated voltage signal, and conditions and regulates said unregulated voltage signal to provide a regulated output signal value V_out which is proportional to an input signal value V_in ; and

a control circuit responsive to said regulated output signal value V_out and said input signal value V_in, for providing a feedback control signal indicative of the difference between V_out and V_in ;

wherein, said variable output pulse modulated power supply receives said feedback control signal and in response thereto drives said regulated output signal value V_out to maintain the relationship (V_out =k*V_in) where k is a constant value.

6. The power amplifier system of claim 2, wherein said variable output pulse modulated power supply includes a pulse width modulator.

7. The power amplifier system of claim 2, wherein said variable output pulse modulated power supply includes a pulse frequency modulator.

8. The power amplifier system of claim 2, wherein said variable output pulse modulated power supply includes a pulse phase modulator.

14. The power amplifier system of claim 2, wherein said input signal value V_in is unipolar.

15. The power amplifier system of claim 2, wherein said input signal value V_in is bipolar.

16. The variable output pulse modulated power supply of claim 2, wherein said variable output pulse modulated power supply includes

a pulse modulator which receives said feedback control signal and provides a drive signal;

a transformer comprising a primary winding and a secondary winding;

means responsive to said drive signal for switching an unregulated DC voltage signal across said primary winding to establish an AC signal in said secondary winding; and

a filter which rectifies said AC signal to provide said regulated output signal value V_out.

17. The variable output pulse modulated power supply of claim 16, wherein said unregulated voltage signal is an AC signal, and said variable output pulse modulated power supply further comprises a diode bridge rectifier which receives said unregulated voltage signal and provides said unregulated DC voltage signal.

18. The variable output pulse modulated power supply of claim 2, wherein said unregulated voltage is a DC signal.