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US 9,178,419 B2Granted
Power source circuit including transistor with oxide semiconductor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsYoshiaki Ito, Takuro Ohmaru
Life of this patent
Estimating the term…
Abstract
An object is to reduce degradation of circuit operation and to reduce the area of the entire circuit. A power source circuit is provided with a first terminal to which first voltage is input; a second terminal to which second voltage is input; a comparator being connected to the first terminal and the second terminal and comparing the first voltage and the second voltage; a digital circuit averaging, integrating, and digital pulse width modulating a first digital signal output from the comparator; a PWM output driver amplifying a second digital signal output from the digital circuit; and a smoothing circuit smoothing the amplified second digital signal.
Claims22
A power source circuit comprising:
- a comparator configured to compare a first voltage and a second voltage;
- a digital arithmetic process circuit configured to average, integrate, and digital pulse width modulate a digital signal output from the comparator;
- a pulse width modulation output driver configured to amplify the digital signal output from the digital arithmetic process circuit;
- a smoothing circuit configured to smooth the digital signal output from the pulse width modulation output driver;
- and
- a DC-DC converter,
- wherein the DC-DC converter comprises a coil, a diode, and a transistor comprising an oxide semiconductor film,
- wherein a first wiring is electrically connected to the source electrode of the transistor,
- wherein a second wiring is electrically connected to the drain electrode of the transistor,
- wherein the gate electrode of the transistor is a same layer as the first wiring and the second wiring,
- wherein the oxide semiconductor film comprises a channel formation region, and
- wherein the oxide semiconductor film contains indium and zinc.
9 more elements
A power source circuit comprising:
- a comparator configured to compare a first voltage and a second voltage;
- a digital arithmetic process circuit configured to average, integrate, and digital pulse width modulate a digital signal output from the comparator;
- a pulse width modulation output driver configured to amplify the digital signal output from the digital arithmetic process circuit;
- and
- a smoothing circuit configured to smooth the digital signal output from the pulse width modulation output driver,
- wherein the comparator, the digital arithmetic process circuit, and the pulse width modulation output driver each comprise a transistor comprising an oxide semiconductor film, a source electrode, a drain electrode, a gate electrode, and a gate insulating film,
- wherein a first wiring is electrically connected to the source electrode,
- wherein a second wiring is electrically connected to the drain electrode,
- wherein the gate electrode is a same layer as the first wiring and the second wiring,
- wherein the oxide semiconductor film comprises a channel formation region, and
- wherein the oxide semiconductor film contains indium and zinc.
8 more elements
A power source circuit comprising:
- a comparator configured to compare a first voltage and a second voltage;
- an adder circuit configured to average a digital signal output from the comparator;
- an adder-subtractor circuit configured to integrate the digital signal;
- a count comparison circuit;
- a latch circuit;
- a pulse width modulation output driver configured to amplify the digital signal output from the latch circuit;
- a smoothing circuit configured to smooth the digital signal output from the pulse width modulation output driver;
- and
- a DC-DC converter,
- wherein the count comparison circuit and the latch circuit are configured to digital pulse width modulate the digital signal output from the adder-subtractor circuit,
- wherein the DC-DC converter comprises a coil, a diode, and a transistor comprising an oxide semiconductor film,
- wherein a first wiring is electrically connected to the source electrode of the transistor,
- wherein a second wiring is electrically connected to the drain electrode of the transistor,
- wherein the gate electrode of the transistor is a same layer as the first wiring and the second wiring,
- wherein the oxide semiconductor film comprises a channel formation region, and
- wherein the oxide semiconductor film contains indium and zinc.
13 more elements
A power source circuit comprising:
- a comparator configured to compare a first voltage and a second voltage;
- an adder circuit configured to average a digital signal output from the comparator;
- an adder-subtractor circuit configured to integrate the digital signal;
- a count comparison circuit;
- a latch circuit;
- a pulse width modulation output driver configured to amplify the digital signal output from the latch circuit;
- and
- a smoothing circuit configured to smooth the digital signal output from the pulse width modulation output driver,
- wherein the count comparison circuit and the latch circuit are configured to digital pulse width modulate the digital signal output from the adder-subtractor circuit,
- wherein the comparator, the adder circuit, the adder-subtractor circuit, the count comparison circuit, the latch circuit, and the pulse width modulation output driver each comprise a transistor comprising an oxide semiconductor film, a source electrode, a drain electrode, a gate electrode, and a gate insulating film,
- wherein a first wiring is electrically connected to the source electrode,
- wherein a second wiring is electrically connected to the drain electrode,
- wherein the gate electrode is a same layer as the first wiring and the second wiring,
- wherein the oxide semiconductor film comprises a channel formation region, and
- wherein the oxide semiconductor film contains indium and zinc.
12 more elements
Dependencies are inferred from the claim text.