DC power supply with reduced ripple
AssigneeSpellman High Voltage Electronics Corp.
InventorCliff Scapellati
Life of this patent
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Abstract
A switching power supply for providing a dc voltage with substantially no ripple includes a rectifier for rectifying an ac supply, a filter for filtering the rectifier output and an inductor for current limiting. The filtered output includes a ripple generated by the equivalent series resistance of the filter. This ripple is sensed and used to generate a correcting signal. The correcting signal is arranged and sized so that when it is superimposed on the filtered output, the ripple is substantially eliminated. Preferably the correcting signal is coupled to the inductor.
Claims17
A low ripple output DC power supply having a DC output comprising:
- input means for receiving an AC input;
- rectifying means for generating a rectifier output from said AC input;
- filter means for generating a filtered output having a DC component and a ripple component;
- ripple sensing means for sensing said ripple component and generating a ripple correcting signal;
- phase correction means for generating a phase corrected signal from said ripple correcting signal, whereby said phase corrected signal and said ripple component have opposite phases;
- and
- summing means for summing said filtered output and said phase corrected signal to generated said DC output consisting substantially of said DC component, whereby said DC output is substantially free of ripple.
A DC power supply for generating a DC output with substantially no ripple comprising:
- an input receiving AC power from an AC supply;
- a transformer transforming said AC power to an output AC power;
- a rectifier rectifying said output AC power into DC power;
- a filter filtering said DC power to generate a filtered power, said filtered power having a DC component and a ripple component;
- an inductor coil for outputting said filtered DC power as output DC power, said inductor coil being provided for current limiting;
- a ripple sensor for sensing said ripple component and for generating a corresponding correcting signal;
- and
- a coupler for coupling said correcting signal to said inductor coil for substantially eliminating said ripple component from said output DC power.
A DC power supply for delivering low ripple DC power of a preselected nominal DC amplitude, said power supply comprising:
- an input receiving AC power;
- a full wave rectifier for generating a full wave rectified output from said AC power;
- a filter for filtering said full wave rectified output, said filter including a resistive element, said filter generating a filtered DC output consisting of a DC component and an undesirable ripple caused by said resistive element;
- a first current limiting coil receiving said filtered DC output, said inductor providing a current limited DC output;
- and
- a ripple eliminator for eliminating said ripple, said ripple eliminator including a sensor coil for sensing said ripple, a generator coil for generating a correcting signal and a first coupling coil for coupling said correcting signal to said first current limiting coil, said first current limiting coil superimposing said correction signal on said filtered DC output for canceling said ripple.
Dependencies are inferred from the claim text.