Linear Control of Phase-Controlled Rectifiers
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Power supplies operating from an AC source frequently use phase-controlled rectifiers to gate the AC input signal variably to a load in response to a control signal. Conventional methods using a linear ramp do not provide a linear relationship between the AC voltage across the load and the control signal. This disclosure proposes a simple way to generate an S-shaped ramp whose use yields a linear relationship between the AC voltage across the load and the control signal. Fig. 1 illustrates a conventional control circuit and the proposed improvements thereto. In the conventional circuit, the upper terminal of resistor R is connected to a DC voltage source + V and path 10 does not exist. (This is illustrated by switch SW set in position 1.