Patent ID: 6941122
Filing Date: 2005-09-06
Classification: H03F,H03G

Abstract:
1. A circuit for compensating temperature of an automatic gain control (AGC) circuit, comprising: a low noise amplifier (LNA) configured to amplify a radio frequency (RF) signal; an attenuation control unit configured to generate an attenuation control signal by sensing the amplified RF signal; a PIN diode attenuator configured to attenuate the RF signal inputted to the LNA by driving a first PIN diode with the attenuation control signal; and a temperature compensation unit configured to compensate a change in an amount of attenuation of the PIN diode caused by a temperature change, wherein the temperature compensation unit comprises: a first voltage divider to divide a power supply voltage; a first operational (OP) amplifier to amplify the divided voltage of the first voltage divider; a second voltage divider to divide an output voltage of the first OP amplifier with a second PIN diode having a same characteristic as the first PIN diode; and a second OP amplifier to amplify an output of the second voltage divider and output the amplified voltage to the PIN diode attenuator.