Reconfiguring impedance matching for high power circuits
View Patent ↗A method and an apparatus are provided for impedance matching using an analog circuit. The method comprises providing the analog circuit to substantially match a start impedance to an end impedance and tuning a performance parameter of an associated circuit using the analog circuit operating at a high power level. The analog circuit may transform the start impedance to the end impedance using a characteristic impedance in a range above the start impedance and the end impedance. By reconfiguring the analog circuit, the associated circuit may operate at one of a first, second, or higher order frequency bands. By using a matching transformation process, reconfigurable matching circuits for medium and/or high power applications may be provided by using available lower power reconfiguration elements. In the matching transformation process, the intermediate impedance at which the reconfiguration is performed is higher than the matching processes used for lower power reconfiguration elements. A relatively smaller and cheaper reconfiguration element having lower parasitics may be used.
1. A method of impedance matching in a circuit including a power amplifier having a first impedance, the power amplifier being configured to provide a signal to a transceiver circuit having a second impedance that is higher than the first impedance, the transceiver circuit being capable of operating in a plurality of frequency bands, the method comprising:
providing an analog circuit to substantially match the first impedance to the second impedance, the analog circuit comprising:
a reconfigurable circuit that operates in a plurality of modes corresponding to the plurality of frequency bands used by the transceiver circuit, the reconfigurable circuit having a third impedance higher than the first impedance and the second impedance;
a first impedance matching circuit coupled between the power amplifier and the reconfigurable circuit for matching the first impedance to the third impedance; and
a second impedance matching circuit coupled between the reconfigurable circuit and the transceiver circuit for matching the third impedance to the second impedance.
2. A method, as set forth in claim 1 , comprising selecting one of the plurality of modes of the reconfigurable circuit in response to changing the frequency band used by the transceiver circuit.
3. A method, as set forth in claim 2 , comprising selecting the third impedance based on an equation P=R×I 2 , where P is power, R is impedance and I is current.
4. A method, as set forth in claim 3 , wherein selecting the third impedance comprises selecting the third impedance to be higher than a threshold impedance to ensure that at least one of a given maximum current and DC-dissipation rating of said matching network element is not violated.
5. A method, as set forth in claim 3 , wherein selecting the third impedance comprises selecting the third impedance to increase a power and current handling capability of the reconfigurable circuit for at least one of medium and higher power applications based on a characteristic impedance of said reconfigurable circuit.
6. A method, as set forth in claim 5 , comprising
transforming the power and current of the reconfigurable circuit during a matching process to serve a different frequency band than an instantaneous operating frequency band.