Tapped-inductor step-down converter and method for clamping the tapped-inductor step-down converter
AssigneeKoninklijke Philips Electronics N.V.
InventorJinrong Qian
Life of this patent
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Abstract
A tapped-inductor step-down converter and method for clamping same with a clamping capacitor so that MOSFETs can be employed to improve circuit efficiency. The converter includes a tapped-inductor and clamping capacitor uniquely arranged to eliminate resonance between the leakage energy of the leaky inductance and the clamping capacitor. Moreover, such arrangement provides for the recycling or recovering of the leakage energy from a leaky inductance of the tapped-inductor to further improve circuit efficiency.
Claims19
A method of clamping a tapped-inductor step-down converter having a tapped-inductor, the method comprising the steps of:
- (a) complementarily switching a first switch to an off-state and maintaining the off-state for a time interval and switching a second switch to an on-state and maintaining the on-state for the time interval;
- (b) clamping a voltage across the first switch during the time interval via a clamping capacitor;
- and,
- (c) during the step (b), transferring the leaky energy of a leaky inductance of a tapped-inductor to the clamping capacitor to recover the leaky energy.
A tapped-inductor step-down converter comprising:
- complementarily switched first and second switches;
- a parallel combination output capacitor and load;
- a tapped-inductor coupled between the first and second switches having a leaky inductance;
- and,
- a clamping capacitor constructed and arranged with the tapped-inductor to clamp a voltage across the first switch, when the first switch is off, to recycle leakage energy from the leaky inductance of the tapped-inductor and to eliminate resonance between the leakage energy of the leaky inductance and the clamping capacitor.
A tapped-inductor step-down converter comprising:
- first and second switches turned on and off in a complementary manner between an on-state and an off-state;
- an output capacitor;
- a load coupled in parallel with the output capacitor;
- a tapped storage inductor having first, second and third windings wherein the first winding, having leaky energy, is tapped to the second winding at a tap and the third winding is coupled to the first and second windings via a path having a diode coupled therealong wherein the second switch is coupled to the tap;
- and,
- a clamping capacitor having one terminal coupled to the third winding and the diode and the other terminal coupled to the first switch and the first winding wherein leaky energy is transferred to the clamping capacitor and a voltage across the clamping capacitor when the first switch is in an off-state clamps the first switch.
Dependencies are inferred from the claim text.