Phase control die power-supply unit

摘要

PURPOSE: To provide the phase control type power unit which has sufficient response characteristics to abrupt variation of an input source voltage. ;CONSTITUTION: With the output (b) of a source voltage detecting circuit 5 and the output (c) of a zero=cross detecting circuit 1 for the source voltage, a lamp waveform generating circuit 3 generates a lamp voltage (d) having a crest value which is reset at each zero-crossing point and proportional to the source voltage. A comparator 8 compares this lamp voltage (d) with a reference value (e) supplied from a microprocessor 4 through a D/A converter 7 to obtain a phase control signal (f). With this phase control signal (f), switching elements such as the thyristor and triac of an electric power control circuit 6 are brought under phase control to supply a stabilized voltage to a power load L connected in series with an electric power control circuit 6. When the source voltage varies abruptly, the microprocessor 4 varies a digital value to a D/A converter 7 to stabilize the output of the electric power control circuit 6 more.;COPYRIGHT: (C)1995,JPO