Switch circuit and high-frequency composite part

Abstract

A switch circuit for selectively switching connection of an antenna side circuit with a reception circuit and a transmission circuit of two communication systems one of which has a reception frequency band partially overlapped with a transmission frequency of the other. The switch circuit includes (a) a first switch unit for switching connection to the antenna side circuit with the transmission circuit side of the first and the second communication systems and the reception circuit side of the first and the second communication system and (b) a second switch unit connected between the first switch unit and the reception circuit of the first end and the second communication system for switching connection of the antenna side circuit with the reception circuit of the first and the second communication system. (c) The transmission circuit side of the first and the second communication system of the first switch unit is connected to a transmission circuit shared by the first and the second communication system. (d) When the transmission circuit of the first and the second communication system is connected to the antenna side circuit, the second switch unit cuts off the connection between the reception circuit of the first communication system and the first switch unit.

1 . A switch circuit for selectively switching the connection of a receiving circuit or a transmitting circuit in two communication systems, in which a receiving frequency bandwidth in a first communication system partially overlaps a transmitting frequency bandwidth in a second communication system, and an antenna circuit, comprising: 
 two switches, including a first switch switching the connection of said antenna circuit to said transmitting circuit of first and second communication systems and the connection of said antenna circuit to receiving circuits of first and second communication systems, and a second switch being connected between said first switch and said receiving circuit of said first and second communication systems to switch the connection of said antenna circuit to said receiving circuit of the first communication system via said first switch, and the connection of said antenna circuit to said receiving circuit of the second communication system via said first switch;    a transmitting circuit common to said first and second communication systems being connected to said transmitting circuit of the first and second communication systems in said first switch; and    said second switch disconnecting said receiving circuit of said first communication system from said first switch, while said transmitting circuit of said first and second communication systems are connected to said antenna circuit.    
   
   
       2 . (canceled)  
   
   
       3 . The switch circuit according to  claim 1 , wherein there is a capacitor between said first switch and said second switch.  
   
   
       4 .- 21 . (canceled)  
   
   
       22 . The switch circuit according to  claim 1 , wherein the operation current of said second switch is lower than that of said first switch.  
   
   
       23 . The switch circuit according to  claim 1 , wherein the operation current of said second switch is 2.5 mA or less.