Sequentially Timed Current-Switch Phase-Modulator Controller
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2005-Feb-19
A sequentially timed current switch phase modulator uses a triggered monostable-comparator to phase lock in sync with two-times the line frequency (i.e., 120 Hz) to control voltage ramping from a programmer. An input sine wave having 208 volts AC line voltage is applied to a transformer. If, by means of a TRIAC or a silicon-controlled rectifier (SCR) the conduction of this voltage is delayed, then the average DC voltage output will be reduced. Phase-control of this delay results in regulation of the output voltage. The power supply can be caused to operate in either of two modes: current and voltage. In the current mode, output current is variable and voltage remains constant. In the voltage mode, output voltage is variable and current remains constant.