Radio front-end circuit

Abstract

In a radio front-end circuit having at least two amplifier-mixer cascades, the amplifiers are switched on or off via the mixers. By switching between the amplifier-mixer cascades, the power consumption is lowered.

What is claimed is:  
     
         1 . A radio front-end circuit comprising at least two amplifiers, an input terminal of each amplifier to be connected to an antenna terminal of the radio, an output terminal of each amplifier being connected to a first input terminal of an associated mixer, a second input terminal of each mixer being connected to a local oscillator, and an output terminal of each mixer to be connected to an input terminal of an intermediate frequency amplifier, and a switch interconnected between the local oscillator and the respective second input terminal of each mixer to connect and disconnect, respectively, the local oscillator to and from, respectively, the respective mixer.  
     
     
         2 . The circuit according to  claim 1 , wherein a control circuit is adapted to control the switch.  
     
     
         3 . The circuit according to  claim 2 , wherein the control circuit is adapted to control the switch in response to at least one of signal strength and interference strength.  
     
     
         4 . The circuit according to  claim 3 , wherein the control circuit is adapted to control the switch to disconnect the local oscillator from one of the mixers in response to at least one of high signal strength and high interference strength, and to connect the local oscillator to that mixer in response to at least one of low signal strength and low interference strength.  
     
     
         5 . The circuit according to  claim 4 , wherein the switch is adapted to switch off a quiescent current of the associated amplifier at substantially the same time as the local oscillator is disconnected from said mixer.  
     
     
         6 . The circuit according to  claim 1 , comprising two amplifiers, wherein one of the amplifiers is a low noise amplifier and the other is a low current linear amplifier.