Transient protection circuit for a dc voltage supply
AssigneeU.S. Philips Corporation
InventorFranciscus A. C. M. Schoofs
Life of this patent
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Abstract
A transient protection circuit for a d.c., voltage supply has a device such as a capacitor (C2) for absorbing transient energy developed on lines (11,12) of the supply. In order to provide such protection without loading the supply with a permanently connected large capacitor, the device for absorbing transient energy (C2) is indirectly connected in parallel with the supply lines (11,12) via a voltage responsive element (D1) which only conducts during the occurrence of a transient.
Claims18
A switched mode power converter with transient protection comprising:
- a resistive element,
- first and second DC supply voltage lines wherein one of said supply lines receives its voltage via the resistive element,
- an inductor and a diode connected in series circuit between the first DC supply voltage line and a first output terminal of the converter,
- a switching transistor coupled between a circuit node in the series circuit and the second DC supply voltage line,
- means for coupling a control electrode of the switching transistor to a source of cyclical switching voltage, and
- a transient protection circuit including a capacitor for absorbing transient electric energy appearing on the DC supply voltage lines and a voltage responsive element for indirectly connecting the capacitor in parallel with the DC supply voltage lines, said voltage responsive element becoming conductive during the occurrence of an electric transient on a DC supply voltage line and independently of the level of DC voltage at said first output terminal.
A converter as claimed in claim 5, further comprising a voltage, clamp coupled across the output lines of the rectifier circuit.
A switched mode power converter with transient protection comprising:
- a resistive element,
- first and second DC supply voltage lines with one of said supply lines coupled to a voltage supply terminal via said resistive element,
- an inductor and a diode connected in series circuit between the first DC supply voltage line and a first output terminal of the converter,
- switching means connected to repetitively couple a circuit point on the first DC supply voltage line to the second DC supply voltage line,
- a capacitor coupled to said first output terminal and to said second DC supply voltage line so as to receive energy via said series circuit, and
- a transient protection circuit including means for absorbing transient energy appearing on a DC supply voltage line and a voltage responsive element for indirectly connecting the energy absorbing means in parallel with the DC supply voltage lines, said voltage responsive element becoming conductive during the occurrence of an electric transient on a DC supply voltage line.
Dependencies are inferred from the claim text.