Adaptive impedance matching module (AIMM) control architectures
View Patent ↗An embodiment of the present invention an apparatus, comprising an adaptive impedance matching module (AIMM) adapted to minimize the magnitude of an input reflection coefficient seen at an RF in port under boundary conditions of a variable load impedance Z L , a tuner connected to the AIMM and including a plurality of variable reactance networks with independent control signals, wherein node voltages are sampled within the tuner; and a microcontroller or digital signal processor (DSP) calculates complex reflection coefficient information from the sampled voltages, the microcontroller or DSP providing a coarse and fine tune function that feeds bias signals to control impedance matching.
1. An apparatus, comprising:
an adaptive impedance matching module (AIMM) adapted to reduce a magnitude of an input reflection at a first port of the AIMM subject to a variable load impedance at a second port of the AIMM,
wherein the AIMM comprises a plurality of voltage tunable capacitors with independent control voltages,
wherein at least one directional coupler samples incident and reflected waves respectively at the first port, and
wherein a logic unit determines reflection coefficient information from said incident and reflected waves, and follows at least one cycle of a coarse tune process for generating bias voltages to control tuning of the plurality of voltage tunable capacitors.
2. The apparatus of claim 1 , wherein the logic unit corresponds to a microcontroller or DSP component that determines the reflection coefficient information from samples provided thereto by at least one analog to digital converter (ADC) coupled to the at least one directional coupler.
3. The apparatus of claim 1 , wherein a look-up table is used to perform said coarse tune process, and wherein said bias voltages are directed to a plurality of digital to analog converters (DACs) that in turn control voltage buffers driving said plurality of voltage tunable capacitors.
4. The apparatus of claim 1 , wherein said bias voltages generated by the coarse tune process are supplied to a plurality of digital to analog converters (DACs) that in turn control voltage buffers driving said plurality of voltage tunable capacitors.
5. The apparatus of claim 1 , wherein the logic unit determines new reflection coefficient information after the at least one cycle of the coarse tune process, and wherein if a magnitude of said new reflection coefficient information has achieved a desired level, then the logic unit fine tunes the plurality of voltage tunable capacitors using small and iterative adjustments to said bias voltages.
6. The apparatus of claim 5 , wherein said fine tunings compensates for variations in manufacturing tolerances or temperature variations of the plurality of voltage tunable capacitors.
7. The apparatus of claim 5 , wherein said fine tuning conforms to a scalar multi-variable minimization algorithm.
8. The apparatus of claim 7 , wherein said multi-variable minimization algorithm corresponds to at least one of:
a downhill simplex method in multidimensions;
a conjugate gradient method in multidimensions; and
a quasi-Newton method.
9. The apparatus of claim 3 , wherein a DC-to-DC converter powers said voltage buffers.
10. The apparatus of claim 1 , wherein the reflection coefficient information is determined from samples supplied to the logic unit by at least one analog to digital converter (ADC) coupled to the at least one directional coupler, wherein said bias voltages are directed to a plurality of digital to analog converters (DACs) that in turn control voltage buffers driving said plurality of voltage tunable capacitors.
11. The apparatus of claim 1 , wherein the plurality of voltage tunable capacitors correspond to at least one of semiconductor varactors, microelectromechanical system (MEMS) varactors, MEMS switched capacitors, semiconductor switched capacitors, and ferroelectric capacitors.
12. The apparatus of claim 1 , wherein each of said plurality of voltage tunable capacitors comprises dielectric material having a variable dielectric constant controllable with a bias voltage.
13. A computer-readable storage medium, comprising computer instructions to:
determine an input reflection coefficient from incident and reflected waves detected at a port of an adaptive impedance matching module (AIMM), wherein the AIMM includes a plurality of voltage tunable capacitors with independent control voltages; and
coarse tune the plurality of voltage tunable capacitors with bias voltages determined according to the input reflection coefficient.
14. The storage medium of claim 13 , comprising computer instructions to perform said course tune according to a look-up table that provides values corresponding to said bias voltages.
15. The storage medium of claim 13 , comprising computer instructions to:
determine a new input reflection coefficient from an additional sampling at the port of the AIMM;
detect that the new input reflection coefficient achieves a desired level; and
fine tune the plurality of voltage tunable capacitors using iterative adjustments to said bias voltages.
16. A method, comprising:
determining a reflection coefficient from a radio frequency signal sampled at a port;
determining at least one bias voltage from the reflection coefficient; and
tuning an adaptive impedance matching module (AIMM) with the at least one bias voltage, wherein the AIMM comprises at least one voltage tunable capacitor with at least one independent control voltage.
17. The method of claim 16 , comprising tuning according to a coarse tuning process.
18. The method of claim 16 , comprising tuning according to a fine tuning process.