Wide frequency range couplers and detectors for power detection in multiple frequency band systems

• US 6,397,077 B1
• Filed: 05/20/1998
• Issued: 05/28/2002
• Est. Priority Date: 05/20/1998
• Status: Expired due to Term

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Jensen, Niels J.
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): Gantt, Alan T.
• Application Number:
  US09/081,702
• Time in Patent Office: 1,469 Days
• Field of Search: 455/550,552,553,127,575,126,571
• US Class Current: 455/553.1
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback

Abstract

A multiband phone capable of transmitting a signal within a plurality of distinct frequency bands having a single wide frequency range power detecting device capable of measuring the power of the transmitted signal over all of the plurality of frequency bands. The multiband phone includes multiple power amplifiers, where each power amplifier amplifies the power of a signal transmitted within a different frequency band. A power amplifier controller is provided for controlling the amount of amplification performed by the power amplifiers, where a switching device switches the connection of the power amplifier controller to a selected power amplifier. The single wide frequency range power detecting device is connected to the output of the all of the power amplifiers through a switching device, where the switching device connects the power detecting device to the particular power amplifier selected for transmission. The power detector then measures the power of the signal transmitted and feeds the measured power back to the power amplifier controller. The power amplifier controller may then adjust the voltage driving the power amplifier connected thereto based upon any difference detected between the desired output power and the measured output power. The performance of the wide frequency range power detecting device is adjusted for the specific transmission frequencies utilized by the multiband phone in order to achieve optimal power detection sensitivity over all of the multiple frequencies.

Claims

1. A multiband phone capable of transmitting signals within multiple distinct frequency bands, where the phone selects a particular frequency at which to transmit the signal and the power of the selected transmission signal is measured and controlled, comprising:

a plurality of power amplifiers, each of the power amplifiers amplifying the power of a signal to be transmitted within a respective one of the multiple distinct frequency bands;

a single, wide frequency range power sensing device for measuring the power of a signal selected to be transmitted from any of the power amplifiers, wherein the amplified signal output by each of the plurality of power amplifiers is connected to the power sensing device;

a transmitting device connected to the output of the power sensing device for transmitting the signal selected to be transmitted; and

a power detector switching device connected between the plurality of amplifiers and the power sensing device for switching the connection of the power sensing device between the plurality of power amplifiers so that the power sensing device is only connected to one of the plurality of power amplifiers at any time.

2. A multiband phone capable of transmitting signals within multiple distinct frequency bands, where the phone selects a particular frequency at which to transmit the signal and the power of the selected transmission signal is measured and controlled, comprising:

a plurality of power amplifiers, each of the power amplifiers amplifying the power of a signal to be transmitted within a respective one of the multiple distinct frequency bands;

a single, wide frequency range power sensing device for measuring the power of a signal selected to be transmitted from any of the power amplifiers, wherein the amplified signal output by each of the plurality of power amplifiers is connected to the power sensing device;

a transmitting device connected to the output of the power sensing device for transmitting the signal selected to be transmitted;

a power amplifier controller for controlling the amount of amplification performed by one of said plurality of power amplifiers; and

a switching device connected to said power amplifier controller for switching the connection of said power amplifier controller between said plurality of power amplifiers such that the power amplifier controller is coupled to only one of the power amplifiers at a time so that said power amplifier controller only controls one of said power amplifiers at a time.

3. The multiband phone of claim 2, further comprising a processing device for monitoring the quality and strength of a received signal and instructing said switching device to switch its connection between respective ones of said plurality of power amplifiers based upon a determination of which of said multiple distinct frequency bands provides an optimal balance between signal quality and signal strength.

4. The multiband phone of claim 3, wherein said processing device includes a stored predetermined relationship between signal strength and a voltage driving said plurality of power amplifiers;

said processing device further instructing said power amplifier controller to adjust the voltage driving said plurality of power amplifiers according to the desired signal strength.

5. The multiband phone of claim 4, further comprising a feedback loop connected to said power sensing device for communicating the power measured by said power detector back to said power amplifier controller,

wherein said power amplifier controller adjusts the voltage driving the power amplifier connected thereto based upon a difference between the desired power output by the connected power amplifier and the measured power output by the connected power amplifier fed back to said power amplifier controller.

6. The multiband phone of claim 2, wherein said single, wide frequency range power sensing device includes:

a wide frequency range directional coupler positioned along a transmission path of the transmission signal passing through said power detector; and

a wide frequency range power detector operably connected to said directional coupler;

wherein said directional coupler couples the transmission signal to said power detector so as to substantially allow only signals traveling in the direction toward the transmission device to be passed through said power detector.

7. The multiband phone of claim 6, wherein said directional coupler is formed having design parameters matched with said multiple distinct transmission frequency bands to provide a desired balance of performance characteristics over all of said multiple distinct transmission frequency bands.

15. The multiband phone of claim 7, wherein the directional coupler is formed of a first conductive trace coupled to the power detector switching device and a second conductive trace coupled to a power detector, wherein the first conductive trace is sensitive to transmission frequencies associated for each one of the plurality of power amplifiers.

17. The multiband phone of claim 2, further comprising a power detector switching device connected between the plurality of power amplifiers and the power sensing device for switching the connection of the power sensing device between the plurality of power amplifiers so that the power sensing device is only connected to one of the plurality of power amplifiers at any time.

8. A wide frequency range power detecting device for measuring the power of a signal transmitted from a multiband phone capable of transmitting signals within multiple distinct frequency bands, comprising:

a wide frequency range directional coupler positioned in a transmission path of a signal to be transmitted;

a wide frequency range power detector connected to said directional coupler for measuring the power of the signal to be transmitted; and

a switching device connected to said directional coupler and further including a plurality of inputs;

each of said inputs connected to receive a signal from a respective one of a plurality of power amplifiers;

said switching device operable to switch the connection of said directional coupler between respective ones of said inputs to operably connect said directional coupler to receive the signal from the respective one of a plurality of power amplifiers.

9. The wide frequency range power detecting device of claim 8, wherein said directional coupler couples the signal selected to be transmitted to said power detector, said directional coupler substantially allowing only signals traveling in the direction of the transmission path to be passed through to said power detector.

10. The wide frequency range power detecting device of claim 9, further comprising a resistor operably connecting said directional coupler to ground, said directional coupler preventing undesirable signals from entering said power detector by transmitting any undesirable signals traveling in an opposite direction to the transmission path through said resistor to be dissipated.

11. The wide frequency range power detecting device of claim 8, wherein said directional coupler is formed having design parameters matched with said multiple distinct transmission frequency bands to provide a desired balance of performance characteristics over all of said multiple distinct transmission frequency bands.

12. A method of forming a wide frequency range power detecting device for use in a multiband telephone capable of transmitting signals within a plurality of distinct frequency bands, the wide frequency range power detecting device having design parameters that provide desired performance characteristics for detecting the power of a transmitted signal over each of the distinct frequency bands, comprising the steps of:

selecting initial design parameters for the power detecting device;

analyzing the performance of the power detecting device at each of the distinct frequency bands using the initial design parameters to determine if the power detecting device is operating with predetermined performance characteristics in each of the distinct frequency bands;

adjusting the design parameters of the power detecting device until the performance of the power detecting device operates with the predetermined performance characteristics over all of said plurality of distinct frequency bands,

wherein the power detector includes a directional coupler having a first conductive trace coupled to at least two power amplifiers residing in a multiband power amplifier and configured to transmit a first signal having a first bandwidth and configured to transmit a second signal having a second bandwidth different from the first bandwidth, and having a second conductive trace coupled to a power measuring device that provides an indication of the signal power to be transmitted;

wherein the design parameters of the power detector which are adjusted include at least one of a length of the first conductive trace, a width of the first conductive trace, and an amount of overlap between the first conductive trace and the second conductive trace.

13. The method of forming a wide frequency range power detecting device of claim 12, wherein the performance characteristics analyzed include the insertion loss of the directional coupler.

14. The method of forming a wide frequency range power detecting device of claim 12, wherein the performance characteristics analyzed include the amount of isolation provided by the directional coupler.

16. The method of claim 12, wherein the directional coupler is formed of the first conductive trace coupled to a power detector switching device such that the first conductive trace is sensitive to each one of a plurality of transmission frequencies associated with each one of the plurality of distinct frequency bands.