Devices and methods for radio-frequency voltage detection

Abstract

Methods and apparatus are provided for detection of voltage levels of RF signals. A first voltage correction is provided based on a thermal voltage and a second voltage correction is provided based on a voltage difference between a detection transistor, used for the rectification of the RF signal, and a reference transistor, to which the RF signal is not supplied. Based on the first and second voltage corrections, a more accurate detector with greater linearity may be obtained. In an embodiment, the second voltage correction may be generated proportional to a hyperbolic tangent of the voltage difference between two transistors, obtained using an additional pair of transistors configured as a differential pair. Applications include the control of a power amplifier output in a wireless device.

What is claimed is: 
     
         1 . A method of detecting a voltage level of a radio-frequency input signal, the method comprising:
 rectifying the radio-frequency input signal with a detection transistor;   dc-offsetting the rectified radio-frequency input signal using a reference transistor that is not configured to receive the radio-frequency input signal;   generating a first correction voltage based on the thermal voltage;   generating a second correction voltage that is based on a voltage difference between the detection transistor and the reference transistor; and   providing an output signal based on the voltage level of the radio-frequency input signal and the first and second correction voltages.