DC-DC converter and semiconductor device
First Claim
1. A semiconductor device comprising:
- a control circuit comprising;
a holding circuit comprising a first transistor; and
an operational amplifier;
a second transistor; and
a first output terminal,wherein a first terminal of the first transistor is electrically connected to the operational amplifier,wherein an output terminal of the operational amplifier is electrically connected to a gate of the second transistor,wherein a first terminal of the second transistor is electrically connected to the first output terminal,wherein the first transistor comprises a first oxide semiconductor film comprising a channel formation region,wherein the second transistor comprises a second oxide semiconductor film comprising a channel formation region,wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises In, M, and Zn,wherein an atomic ratio of In to M in the second oxide semiconductor film is higher than an atomic ratio of In to M in the first oxide semiconductor film, andwherein M is at least one of Ga, Y, Zr, La, Ce, and Nd.
1 Assignment
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Accused Products
Abstract
A DC-DC converter with low power consumption and high power conversion efficiency is provided. The DC-DC converter includes a first transistor and a control circuit. The control circuit includes an operational amplifier generating a signal that controls switching of the first transistor, a bias circuit generating a bias potential supplied to the operational amplifier, and a holding circuit holding the bias potential. The holding circuit includes a second transistor and a capacitor to which the bias potential is supplied. The first transistor and the second transistor include a first oxide semiconductor film and a second oxide semiconductor film, respectively. The first oxide semiconductor film and the second oxide semiconductor film each contain In, M (M is Ga, Y, Zr, La, Ce, or Nd), and Zn. The atomic ratio of In to M in the first oxide semiconductor film is higher than that in the second oxide semiconductor film.
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Citations
21 Claims
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1. A semiconductor device comprising:
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a control circuit comprising; a holding circuit comprising a first transistor; and an operational amplifier; a second transistor; and a first output terminal, wherein a first terminal of the first transistor is electrically connected to the operational amplifier, wherein an output terminal of the operational amplifier is electrically connected to a gate of the second transistor, wherein a first terminal of the second transistor is electrically connected to the first output terminal, wherein the first transistor comprises a first oxide semiconductor film comprising a channel formation region, wherein the second transistor comprises a second oxide semiconductor film comprising a channel formation region, wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises In, M, and Zn, wherein an atomic ratio of In to M in the second oxide semiconductor film is higher than an atomic ratio of In to M in the first oxide semiconductor film, and wherein M is at least one of Ga, Y, Zr, La, Ce, and Nd. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor device comprising:
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a control circuit comprising; a holding circuit comprising a first transistor; and an operational amplifier; a second transistor; and a first output terminal, wherein a first terminal of the first transistor is electrically connected to the operational amplifier, wherein an output terminal of the operational amplifier is electrically connected to a gate of the second transistor, wherein a first terminal of the second transistor is electrically connected to the first output terminal, wherein the first transistor comprises a first oxide semiconductor film comprising a channel formation region and a pair of first gate electrodes between which the first oxide semiconductor film is provided, wherein the second transistor comprises a second oxide semiconductor film comprising a channel formation region and a pair of second gate electrodes between which the second oxide semiconductor film is provided, wherein a potential of one of the pair of first gate electrodes is lower than a potential of the other of the pair of first gate electrodes, wherein the pair of second gate electrodes is electrically connected to each other, wherein the first oxide semiconductor film and the second oxide semiconductor film each contain In, M, and Zn, and wherein M is at least one of Ga, Y, Zr, La, Ce, and Nd. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A semiconductor device comprising:
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a control circuit comprising; a holding circuit comprising a first transistor; and an operational amplifier; a second transistor; and a first output terminal, wherein a first terminal of the first transistor is electrically connected to the operational amplifier, wherein an output terminal of the operational amplifier is electrically connected to a gate of the second transistor, wherein a first terminal of the second transistor is electrically connected to the first output terminal, wherein the first transistor comprises a first oxide semiconductor film comprising a channel formation region, wherein the second transistor comprises a second oxide semiconductor film comprising a channel formation region, wherein the first oxide semiconductor film comprises In, M, and Zn, wherein M is at least one of Ga, Y, Zr, La, Ce, and Nd, and wherein the second oxide semiconductor film comprises at least one of In and Zn. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification