Thomson Licensing S.a.

Deutsche Thomson-brandt Gmbh

Thomson Licensing

Reinhard Koegel

Jean-Paul Louvel

Eugen Kizmann

The protection circuit for a switch has an energy-storage means, which is connected to a control input of the switch and which is charged with a delay via resistance means when a control voltage is present and is discharged via switching means when the control voltage is low or absent, and has a switching stage which is connected to a supply voltage, is switched on when a specific threshold voltage is present across the energy-storage means and in this way reduces the supply voltage. In one exemplary embodiment, when the switching stage is switched on, the charge which is dissipated from the supply voltage is at least partially routed to the energy-storage means via a diode which is connected in parallel with the said energy-storage means, so that the phase during which the switching stage is switched on is lengthened and the energy-storage means, in this case a capacitor, is completely discharged.

Protection circuit for a switch, and a switched-mode power supply

A switched mode power supplier having an improved power factor, that is to say a reduced harmonic load on the mains comprising a switch mode power supply with a reduced harmonic load on mains, comprising a mains rectifier being coupled to a charge capacitor and to a series circuit, the series circuit comprising a decoupling element, a primary winding of a transformer, a switching transistor, and an energy storage capacitor coupled in parallel with the primary winding and the switching transistor, with the voltage thereacross being a smoothed DC voltage, the charge capacitor being further coupled to a tap of said primary winding via a second series circuit comprising an inductor and a diode, and the inductor and the diode being connected via a second diode to a point with a fixed voltage.

Growing community of inventors

Brigachtal, Germany

Reinhard Koegel