DC-DC converter
AssigneeTexas Instruments Incorporated
InventorKatsuya Ikezawa
Life of this patent
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Abstract
The objective of this invention is to reduce the current flowing through the inductance element in a step-up/step-down DC—DC converter and to control the ripple in the output voltage. In the DC—DC converter, four states, that is, the first state [1] of (M1, M2)=(off, on) and (M3, M4)=(on, off), the second state [2] of (M1, M2)=(on, off) and (M3, M4)=(off, on), the third state [3] of (M1, M2)=(on, off) and (M3, M4)=(on, off), and the fourth state [4] of (M1, M2)=(off, on) and (M3, M4)=(off, on) are repeated in a prescribed order, preferably in the order . . . [1]→[4]→[2]→[3]→[1] . . . or . . . [1]→[3]→[2]→[4]→[1] . . . .
Claims13
DC—DC converter having the following:
- a first switching element connected between a voltage input terminal and
- a first terminal of an inductance element;
- a second switching element connected between a reference potential and said first terminal;
- a third switching element connected between a voltage output terminal and a second terminal of said inductance element;
- a fourth switching element connected between the reference potential and said second terminal;
- and
- a control unit, which controls the switching of the aforementioned first, second, third, and fourth switching elements such that in a first state, the first switching element is off, the second switching element is on, the third switching element is on, and the fourth switching element is off;
- in a second state, the first switching element is on, the second switching element is off, the third switching element is off, and the fourth switching element is on;
- in a third state, the first switching element is on, the second switching element is off, the third switching element is on, and the fourth switching element is off, and in a fourth state, the first switching element is off, the second switching element is on, the third switching element is off, and the fourth switching element is on;
- and the state transitions are from first state to third state, from third state to second state, from second state to fourth state, and from fourth state to first state.
DC—DC converter characterized in that the converter has the following:
- a first switching element connected between a voltage input terminal and one of the terminals of an inductance element;
- a second switching element connected between a reference potential and one of the terminals of the aforementioned inductance element;
- a third switching element connected between a voltage output terminal and the other terminal of the aforementioned inductance element;
- a fourth switching element connected between the reference potential and the other terminal of the aforementioned inductance element;
- a first control circuit, which compares a voltage level of a feed forward signal corresponding to an input voltage to the aforementioned voltage input terminal and a first reference voltage with a voltage level of a first triangular signal having a prescribed frequency and which turns on/off the first and second switching elements in a complementary manner corresponding to a comparison result;
- a second control circuit, which compares the voltage level of a feedback signal corresponding to the output voltage from the aforementioned voltage output terminal and a second reference voltage with the voltage level of a second triangular signal having the aforementioned prescribed frequency and which turns on/off the third and fourth switching elements in a complementary manner corresponding to the comparison result;
- a polarity or phase relationship between the aforementioned first and second triangular signals is set such that in the first state, the first switching element is off, the second switching element is on, the third switching element is on, and the fourth switching element is off;
- in the second state, the first switching element is on, the second switching element is off, the third switching element is off, and the fourth switching element is on;
- in the third state, the first switching element is on, the second switching element is off, the first switching element is on, and the fourth switching element is off;
- and in the fourth state, the first switching element is off, the second switching element is on, the third switching element is off, and the fourth switching element is on;
- wherein the first, second, third, and fourth states occur in a prescribed order in one period of the aforementioned first or second triangular signal.
The DC—DC converter described in 4, characterized by having a feed forward signal generating circuit, which multiplies the aforementioned input voltage by a prescribed coefficient, then adds a prescribed constant to the multiplication result, and outputs the sum as the aforementioned feed forward signal.
Dependencies are inferred from the claim text.