Semiconductor Device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsTakuro KANEMURA, Yoshiyuki KUROKAWA, Hiromichi GODO, Kzuki TSUDA, Satoru OHSHITA, Hiidefumi RIKIMARU
Life of this patent
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Abstract
A novel semiconductor device is provided. An analog signal is converted into a digital signal using a comparison portion comparing two current values, a control portion, and a current output digital-analog conversion portion. The control portion has a function of generating a sign bit showing a magnitude relation between the two current values, a function of converting a difference between the two current values into a digital signal by successive approximation, and a function of outputting the sign bit and the digital signal.
Claims15
A semiconductor device comprising:
- a comparator having a first input terminal and a second input terminal;
- a first DA converter (Digital to Analog converter) having an output terminal electrically connected to the first input terminal of the comparator;
- a second DA converter having an output terminal electrically connected to the second input terminal of the comparator;
- and
- a control portion electrically connected to the comparator, the first DA converter, and the second DA converter,
- wherein the comparator is configured to compare a value of a first current flowing to the first input terminal with a value of a second current flowing to the second input terminal and generate an output signal,
- wherein the control portion is configured to generate a digital signal and a sign bit in accordance with the output signal, supply the digital signal to at least one of the first DA converter and the second DA converter,
- wherein the first DA converter is configured to add a third current in accordance with the digital signal to the first current,
- wherein the second DA converter is configured to flow a fourth current in accordance with the digital signal to the second current, and
- wherein the comparator is configured to compare values of the first current and the third current flowing to the first input terminal with values of the second current and the fourth current flowing to the second input terminal and generate the output signal.
A light-emitting apparatus comprising a pixel portion and a peripheral circuit,
- wherein the peripheral circuit comprise a semiconductor device comprising:
- a comparator having a first input terminal and a second input terminal;
- a first DA converter (Digital to Analog converter) having an output terminal electrically connected to the first input terminal of the comparator;
- a second DA converter having an output terminal electrically connected to the second input terminal of the comparator;
- and
- a control portion electrically connected to the comparator, the first DA converter, and the second DA converter,
- wherein the comparator is configured to compare a value of a first current flowing to the first input terminal with a value of a second current flowing to the second input terminal and generate an output signal,
- wherein the control portion is configured to generate a digital signal and a sign bit in accordance with the output signal, supply the digital signal to at least one of the first DA converter and the second DA converter,
- wherein the first DA converter is configured to add a third current in accordance with the digital signal to the first current,
- wherein the second DA converter is configured to flow a fourth current in accordance with the digital signal to the second current, and
- wherein the comparator is configured to compare values of the first current and the third current flowing to the first input terminal with values of the second current and the fourth current flowing to the second input terminal and generate the output signal.
Dependencies are inferred from the claim text.