Patent ID: 8235693

Claim:
A power supply device for an electrically driven injection molding machine for supplying electric power to a servo motor for driving a member of the electrically driven injection molding machine, the power supply device comprising: an AC/DC converter; and a power accumulating device, wherein: the AC/DC converter is configured to convert an AC voltage into a DC voltage and to supply the DC voltage to a servo amplifier for driving the servo motor; and the power accumulating device comprises a power accumulating circuit and a control circuit; the power accumulating circuit comprises a first loop circuit and a second loop circuit; the first loop circuit comprises a coil, a first switch circuit and a capacitor coupled in series between a positive terminal and a negative terminal; the second loop circuit comprises the coil and a second switch circuit coupled in series between the positive terminal and the negative terminal; the power accumulating device is configured to accumulate electric power supplied from the DC circuit in the capacitor, and when accepting a predetermined output request, to supply a DC voltage to the DC circuit to thereby supply to the servo amplifier a DC voltage higher than the DC voltage generated from the AC/DC converter.