Self-oscillating converter
AssigneeTexas Instruments Deutschland GmbH
InventorsNeil Gibson, Kevin Scoones
Life of this patent
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Abstract
A converter has a main feedback path and two auxiliary feedback paths from an output node to an auxiliary differential input pair of a comparator. The auxiliary feedback paths have different RC time constants so that a differential ramp signal is effectively applied to the auxiliary differential inputs of the comparator. The circuit design compensates for a negligibly small equivalent series resistor of an output capacitor so that modern capacitors may be used without compromising the stable oscillation of the converter.
Claims9
A self-oscillating converter including a load capacitor with a negligibly small equivalent series resistor and a feedback loop with a comparator to which a voltage difference between a reference voltage and an output voltage of the converter is applied, comprising:
- a first auxiliary feedback path from an switched node to a first input of a first differential input of the comparator, the first auxiliary feedback path having a first RC time constant;
- a second auxiliary feedback path from the switched node to a second input of the first differential input of the comparator, the second auxiliary feedback path having a second RC time constant different from the first time constant;
- and
- circuitry for adding a differential voltage between the first and second differential inputs to the voltage difference applied to the comparator for generating a voltage equivalent to a voltage that would have been generated across the equivalent series resistance of the load capacitor had the equivalent series resistance not been negligible.
Dependencies are inferred from the claim text.