Patent ID: 7075345
Filing Date: 2006-07-11
Classification: H03D

Abstract:
1. A frequency converter which converts a first current signal having a first frequency into a second current signal having a second frequency different from the first frequency, comprising: an adder which adds the first current signal and a reference current signal to output a third current signal; and a switching circuit (a) including a field effect transistor having a gate terminal which is grounded for radio-frequency currents, and (b) configured to (i) pass a larger current component of the third current signal to obtain the second current signal, when the third current signal includes the larger current component larger in magnitude than a threshold current, and (ii) block a smaller current component of the third current, when the third current signal includes the smaller current component which is smaller in magnitude than the threshold current; and a constant current source which is connected to a source terminal of the field effect transistor, and generates a current substantially equal in magnitude to the threshold current.