Patent ID: 7557668

Claim:
An injection-locked frequency divider, suitable for performing a frequency division action on an injection signal to generate a frequency division signal, comprising: a variable reactance unit, having a first connecting terminal and a second connecting terminal, for adjusting a reactance value of the injection-locked frequency divider and outputting the frequency division signal through the first connecting terminal and the second connecting terminal; a signal injection unit, coupled to the first connecting terminal and the second connecting terminal, for receiving the injection signal; a first switch, with a first terminal coupled to the first connecting terminal and a control terminal coupled to the second connecting terminal; a second switch, with a first terminal coupled to the second connecting terminal and a control terminal coupled to the first connecting terminal; a first transformer, having a primary-side coil and a secondary-side coil, the primary-side coil of the first transformer being coupled between the first connecting terminal and a ground terminal, and the secondary-side coil of the first transformer being coupled between the second terminal of the first switch and an operating voltage; and a second transformer, having a primary-side coil and a secondary-side coil, the primary-side coil of the second transformer being coupled between the second connecting terminal and the ground terminal, and the secondary-side coil of the second transformer being coupled between the second terminal of the second switch and the operating voltage.