Regulated rectifier d.c. power supply

Claim 1

Regulated a.c.-d.c. rectifier and power supply with sinusoidal network current input and high-power factor having power input terminals (S1, S2) adapted for connection to a power network supplying input electrical energy at commercial power voltage (U N ) and frequency (f N ); power output terminals (L1, L2) supplying d.c. output power at a regulated voltage (U o ); a rectifier (12) connected to receive input electrical energy from the input terminals, rectifying said energy and supplying a rectified pulsating d.c. output; having a pulsating d.c. output voltage (U E ); an inductance(L S ) connected between the d.c. output of the rectifier and the output terminals (L1, L2); a power storage capacitor (C L ) connected across the output terminals (L1, L2); a diode (d1) connected between the inductance and the power storage capacitor to prevent discharge of the capacitor through the inductance; a controlled electronic switch (T Q ) coupled to the inductance (L S ) and affecting current flow (i L ) through the inductance; and a control circuit (16) controlling conduction of the electronic switch (T Q ) in dependence on (a) instantaneous charge state of the inductance represented by an L signal, (b) instantaneous rectified pulsating d.c. output voltage (U E ) delivered by the rectifier represented by a U E signal, and (c) instantaneous output voltage (U o ) of d.c. power delivered to the d.c. power terminals (L1, L2) and also applied across said power storage capacitor (C L ), represented by a U o signal wherein, in accordance with the invention the control circuit (16) comprises a first threshold switch (STc) connected to and controlling conduction of the elctronic switch (T Q ); a control capacitor (C12) coupled (24, 38) to receive the U E signal representative of the instantaneous rectified d.c. output voltage (U E ) supplied by the rectifier, further coupled (32, 24) to receive the U o signal representative of the instantaneous output power voltage (U o ), and further coupled (22, 28; 30, STa, STb) to receive the L signal representative of the charge state of the inductance (L S ), said U E signal, the U o signal, and the L signal controlling said control capacitor to reverse its charge state and recharge to assume an oppositely charged state, said control capacitor being connected to control the threshold switch (STc) to render the electronic switch (T Q ) conductive for a period of time which corresponds to the time of charge reversal and recharge of the control capacitor (C12) and until the voltage on the control capacitor, upon recharge into the oppositely charged state has reached an upper hysteresis threshold level of the threshold switch (STc), said charge reversal and recharging time being determined by the relative values of said U E signal representative of the rectified d.c. output voltage (U E ) supplied by the rectifier (12), the U o signal representative of output power voltage (U o ) and the time instant when said upper hysteresis threshold level is reached being determined when the L signal representative of the charge state of the inductance (L S ) has a characteristic which signifies that the inductance is completely discharged.