Synchronized rectifier voltage step down DC-DC converter and control circuit therefor
AssigneeHitachi, Ltd.
InventorsNorikazu Tokunaga, Kenichi Onda, Takeshi Onaka, Ryouhei Saga, Akihiko Kanouda
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Abstract
A DC-DC converter is provided with a calculation circuit which estimates current flowing through a reactor in a control circuit for controlling a switching element and a circulation use element, and the switching element and the circulation use element are controlled by making use of the calculated reactor current value. Thereby, a DC-DC converter which operates in a high efficiency and with low ripple even during a light load condition and realizes a high response performance during load variation is provided.
Claims22
A synchronized rectifier voltage step down DC-DC converter, comprising:
- a first switching element and a circulation use switching element connected in series between DC input terminals of the DC-DC converter;
- a reactor and a capacitor connected in series between a junction of the switching element and the circulation use element, and a lower potential terminal of the DC input terminals;
- and
- a control circuit which controls operation of the first switching element and the circulation use switching element;
- wherein
- through ON/OFF control of the first switching element and the circulation use switching element a DC output is obtained at terminals of the capacitor;
- the control circuit includes a first calculation circuit which calculates current flowing through the reactor;
- and
- the first switching element and the circulation use switching element are controlled as a function of calculated current flowing through the reactor.
Dependencies are inferred from the claim text.