Impedance matching circuit for radio-frequency amplifier

Abstract

An impedance matching circuit for an amplifier can include a first coil and a second coil configured as an autotransformer. A first end of the first coil can be configured to connect to a voltage source for the amplifier, and a second end of the first coil can be connected to an output of the amplifier. A first end of the second coil can be connected to the second end of the first coil, and a second end of the second coil can be connected to an output node. The impedance matching circuit can also include a capacitor connected to the second end of the first coil.

1 - 20 . (canceled) 
     
     
         21 . An impedance matching circuit for an amplifier, the impedance matching circuit comprising:
 a first coil having a first end configured to connect to a voltage source for the amplifier, the first coil having a second end connected to an output of the amplifier;   a second coil having a first end connected to the second end of the first coil and having a second end connected to an output node, the first coil and the second coil being configured as an autotransformer; and   a capacitor having a first end connected to the second end of the first coil and having a second end connected to at least one of the first end of the first coil, the second end of the second coil, or a ground.   
     
     
         22 . The impedance matching circuit of  claim 21  further comprising the amplifier, the amplifier including a transistor, a collector of the transistor being connected to the second end of the first coil and the first end of the second coil, a base of the transistor being configured to connect to an input for the amplifier. 
     
     
         23 . The impedance matching circuit of  claim 21  wherein the second end of the capacitor is connected to the first end of the first coil, the capacitor being electrically parallel with the first coil. 
     
     
         24 . The impedance matching circuit of  claim 21  wherein the second end of the capacitor is connected to the second end of the second coil, the capacitor being electrically parallel with the second coil. 
     
     
         25 . The impedance matching circuit of  claim 21  wherein the second end of the capacitor is connected to the ground, the capacitor being part of a harmonic trap circuit to trap a harmonic associated with an amplified signal. 
     
     
         26 . The impedance matching circuit of  claim 25  wherein the harmonic includes a second harmonic associated with the amplified signal. 
     
     
         27 . The impedance matching circuit of  claim 25  wherein the harmonic includes a third harmonic associated with the amplified signal. 
     
     
         28 . The impedance matching circuit of  claim 21  wherein the first coil is implemented in a first plane and the second coil is implemented in a second plane, the first plane being a distance from the second plane. 
     
     
         29 . The impedance matching circuit of  claim 28  wherein at least one of a trace of the first coil is wider than a trace of the second coil or the trace of the first coil is thicker than the trace of the second coil. 
     
     
         30 . The impedance matching circuit of  claim 21  further comprising an output capacitor implemented between the second end of the second coil and the output node, the output capacitor being configured to resonate out leakage inductance associated with the autotransformer. 
     
     
         31 . The impedance matching circuit of  claim 21  further comprising a first substrate to support the first coil, a second substrate to support the second coil, and an insulator layer implemented between the first coil and the second coil. 
     
     
         32 . The impedance matching circuit of  claim 31  further comprising a conductive element implemented through the insulator layer, the conductive element configured to provide a connection between the first end of the second coil and the second end of the first coil. 
     
     
         33 . The impedance matching circuit of  claim 21  wherein the impedance matching circuit is implemented as an integrated passive device (IPD). 
     
     
         34 . The impedance matching circuit of  claim 21  wherein the first coil is configured to provide passage of a DC current for the amplifier and provide a low impedance path for a radio-frequency current. 
     
     
         35 . The impedance matching circuit of  claim 21  wherein the amplifier is implemented as a power amplifier. 
     
     
         36 . A radio-frequency module comprising:
 a packaging substrate configured to receive a plurality of components;   an amplifier implemented on the packaging substrate and configured to provide an amplified signal at an output; and   an impedance matching circuit coupled to the output of the amplifier, the impedance matching circuit including a first coil, a second coil, and a capacitor, the first coil and the second coil being configured as an autotransformer, a first end of the first coil configured to connect to a voltage source for the amplifier, a second end of the first coil connected to the output of the amplifier, a first end of the second coil connected to the second end of the first coil, a second end of the second coil connected to an output node, a first end of the capacitor connected to the second end of the first coil, a second end of the capacitor connected to at least one of the first end of the first coil, the second end of the second coil, or a ground.   
     
     
         37 . The radio-frequency module of  claim 36  wherein a first portion of the autotransformer is implemented in a passive device that is mounted on the packaging substrate, and a second portion of the autotransformer is implemented as a part the packaging substrate. 
     
     
         38 . The radio-frequency module of  claim 37  wherein the first coil is implemented in the passive device, and the second coil is implemented as part of the packaging substrate. 
     
     
         39 . The radio-frequency module of  claim 36  wherein at least a portion of the autotransformer is implemented as a device that is mounted over the packaging substrate, the device including a substantially flat surface. 
     
     
         40 . A wireless device comprising:
 a transceiver configured to generate a signal;   a front-end module in communication with the transceiver and including an amplifier configured to amplify the signal and provide an amplified signal at an output, the front-end module further including an impedance matching circuit coupled to the output of the amplifier, the impedance matching circuit including a first coil, a second coil, and a capacitor, the first coil and the second coil being configured as an autotransformer, a first end of the first coil configured to connect to a voltage source for the amplifier, a second end of the first coil connected to the output of the amplifier, a first end of the second coil connected to the second end of the first coil, a second end of the second coil connected to an output node, a first end of the capacitor connected to the second end of the first coil, a second end of the capacitor connected to at least one of the first end of the first coil, the second end of the second coil, or a ground; and   an antenna in communication with the front-end module and configured to support transmission of the amplified signal.