Digitally controlled oscillators with current mirrors and negative feedback circuits therein that support high supply voltage penetration (PSSR) and low noise characteristics

摘要

A digitally controlled oscillator (DCO) has a current mirror (31), which is configured to generate a reference current (I) at a first output terminal thereof, and a supply current (I), which is a size proportional to a size of the reference current ( I) has, at a second output port thereof. An oscillation circuit (33) is provided which responds to the supply current (I) at an input node (IN) thereof. This oscillation circuit (33) generates a periodic output signal (OUT) which has a frequency (f) which varies in response to changes in the magnitude of the supply current (I). A variable resistance circuit (32) is provided which responds to a first control signal (CTR1) which has a size which influences a value of a resistance which is provided between a first node thereof which receives the reference current (I) and one second knot of it. A negative feedback circuit (34) is provided, which has a first and a second current-carrying connection, is electrically connected to the first output connection of the current mirror (31) and the first node of the variable resistance circuit (32), and a control connection, which is electrically connected to the Input node of the oscillation circuit (33) is coupled.