SEMICONDUCTOR DEVICE AND COMMUNICATION DEVICE
First Claim
1. A semiconductor device comprising:
- a variable gain type differential amplifier circuit which receives a gain setting signal, amplifies differential input signals by a gain indicated by the gain setting signal, and outputs differential output signals; and
a correcting circuit which cancels an offset voltage generated in the differential amplifier circuit,the correcting circuit cancelling the offset voltage by receiving the gain setting signal, generating a correction voltage changed in accordance with the gain, and adding the correction voltage to the differential output signals.
1 Assignment
0 Petitions
Accused Products
Abstract
A semiconductor device capable of achieving high speed performance in addition to correction of differential offset and a communication device provided with the semiconductor device are provided. For example, there are provided: a variable gain type differential amplifier circuit VGA1 which receives a gain setting signal ASET, which amplifies differential input signals INP and INN by a gain indicated by the gain setting signal, and which outputs differential output signals OUTP′ and OTUN′; and an offset correcting circuit unit OFCBK1 which cancels an offset voltage (VOF and VOFO) generated in the VGA1. Here, the OFCBK1 cancels an output offset voltage VOFO (which results in an input offset voltage VOF) by receiving the ASET, generating a correction voltage changed in accordance with the gain, and adding the correction voltage to the OUTP′ and OUTN′.
8 Citations
13 Claims
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1. A semiconductor device comprising:
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a variable gain type differential amplifier circuit which receives a gain setting signal, amplifies differential input signals by a gain indicated by the gain setting signal, and outputs differential output signals; and a correcting circuit which cancels an offset voltage generated in the differential amplifier circuit, the correcting circuit cancelling the offset voltage by receiving the gain setting signal, generating a correction voltage changed in accordance with the gain, and adding the correction voltage to the differential output signals. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor device comprising:
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a variable gain type first differential amplifier circuit to which first differential input signals and a first gain setting signal are inputted, which amplifies the first differential input signals by a first gain indicated by the first gain setting signal, and which outputs first differential output signals to differential output nodes; a variable gain type second differential amplifier circuit to which second differential input signals having a reverse polarity from but the same level as those of the first differential input signals and a second gain setting signal are inputted, which amplifies the second differential input signals by a second gain indicated by the second gain setting signal, and which adds second differential amplification signals of a result of this amplification to the first differential output signals in the differential output nodes; and a correcting circuit which cancels a first offset voltage generated in the first differential amplifier circuit, and besides, which cancels a second offset voltage generated in the second differential amplifier circuit, and the correcting circuit cancelling the first offset voltage by receiving the first gain setting signal, generating a first correction voltage changed in accordance with the first gain, and adding the first correction voltage to the first differential output signals, and besides, cancelling the second offset voltage by receiving the second gain setting signal, generating a second correction voltage changed in accordance with the second gain, and adding the second correction voltage to the second differential output signals. - View Dependent Claims (8, 9, 10)
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11. A communication device comprising:
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a first semiconductor device which transmits differential signals; a first wiring board on which the first semiconductor device is mounted; a second semiconductor device which receives the differential signals; a second wiring board on which the second semiconductor device is mounted; and a communication route through which the differential signals are transferred from the first wiring board to the second wiring board, the second semiconductor device including; a variable gain type differential amplifier circuit which is arranged at an input first stage, which receives a gain setting signal, which amplifies the differential signals received with a gain indicated by the gain setting signal, and which outputs differential output signals; and a correcting circuit which cancels an offset voltage generated in the differential amplifier circuit, and the correcting circuit cancelling the offset voltage by receiving the gain setting signal, generating a correction voltage changed in accordance with the gain, and adding the correction voltage to the differential output signals. - View Dependent Claims (12, 13)
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Specification