SMPS having a safety arrangement, a method of operating a SMPS, and a controller therefor

摘要

A switched mode power supply (SMPS) is disclosed. The SMPS includes a mechanism for discharging charge stored in an input capacitor, upon the SMPS becoming disconnection from the mains, for instance by being unplugged. The SMPS includes a detector for detecting the disconnection of the mains, and a discharge circuit. The discharge circuit comprises a discharge element. The discharge element may be a part of the SMPS which is used otherwise, for instance, a high-voltage current source, or a bus capacitor or it may be an additional element, for instance a resistance load. The discharge circuit is adapted for, in response to the detector detecting a disconnection of the mains, discharging the input capacitor along a path. The detector controls a switch which engages the discharge circuit upon the detection. The switch forms a part of the discharge path.

主权项

1. A switched mode power supply comprising:
an input to which a mains supply is connectable; an input filter including an input capacitor; a rectifier stage coupled to the input capacitor; a converter stage, and a safety arrangement, the safety arrangement having a detector for detecting a disconnection of the mains supply from the input; and a switchable discharge path including a discharge element, the discharge path being arranged to discharge charge stored in the input capacitor through the discharge element in response to the detector detecting a disconnection of the mains supply from the input, wherein the path is switchably connected to a node located between the rectifier stage and the power factor correction stage, the path includes a part of the power factor correction stage, the discharge element is a capacitor located on an output side of the power factor correction stage and different from the input capacitor, the power factor correction stage comprises a switch which is adapted to be cyclically switched, and the path is configured so as to charge the capacitor upon cyclic switching of the switch.