Canon Kabushiki Kaisha

Hiroyuki Nakamura

Nobuyuki Hirayama

Ryo Kasai

Kimiyuki Hayasaki

Tatsuo Furukawa

Shigeki Kondo

Shinichi Omo

Makoto Takeuchi

Yoji Serizawa

Seiji Uchiyama

Kazuro Yamada

Yukihide Ushio

Akio Noguchi

Wataru Endo

Shimpei Matsuo

Kei Fujita

Toshihiko Ichise

Shunichi Kaizu

Seiji Kamei

A printing apparatus comprising a light-emitting element, a light-receiving element configured to output a monitor current based on a light-emitting amount from the light-emitting element, a comparison unit connected to the light-receiving element and configured to compare the monitor current with a reference current, a driving unit configured to drive the light-emitting element based on the comparison result, a current generation unit configured to generate a first current, and a conversion unit arranged in a path between the current generation unit and the comparison unit, the conversion unit outputting, upon receiving a control signal, the reference current based on the control signal and the first current.

Printing apparatus and substrate for driving light-emitting element

A driving circuit for causing a light emitting element to emit light in response to a driving signal is provided. The driving circuit comprising a first current supply circuit that starts to supply a driving current to the light emitting element in response to the driving signal, a second current supply circuit that starts to supply a supplementary current to the light emitting element in response to the driving signal. The second current supply circuit stops to supply the supplementary current upon detecting that a voltage applied to the light emitting element has reached a threshold voltage.

Driving circuit for light emitting element

A device includes a first element substrate and a second element substrate for driving a driving element; a first signal input unit connected to an input terminal of the first element substrate; a second signal input unit connected to an input terminal of the second element substrate; and a signal output unit. Each of the first and second element substrates includes a driving element, a first signal generation unit configured to output a first signal, a second signal generation unit configured to output a second signal, an input terminal, an output terminal, and a selection unit configured to receive a signal from the first and the second signal generation units, select one of a state of the first signal, a state of the second signal, and a high-impedance state on the basis of the selection signal input from the input terminal, and output the state to the output terminal.

Device and apparatus for controlling same

A surge protection circuit comprises a surge detection circuitfor detecting a surge applied to a semiconductor integrated circuit, and a protection elementfor absorbing the surge. The protection element is connected between a signal terminal for supplying a signal to the semiconductor integrated circuit and a power source terminal for supplying a power source voltage. When the power source voltage is not larger than a voltage enough to normally operate the semiconductor integrated circuit and the surge detection circuit does not detect the surge, the protection element is set in a current limiting state. When the power source voltage is not larger than a voltage enough to normally operate the semiconductor integrated circuit and the surge detection circuit detects the surge, the protection element is set in a current non-limiting state.

Protection circuit for semiconductor integrated circuit and driving method therefor

A light emitting element driving circuit for driving a light emitting element in accordance with a differential data signal for causing the light emitting element to turn on or turn off is provided. The circuit includes a first transistor, a first constant current source connected to a drain and gate of the first transistor and configured to supply a constant current through the drain and source of the first transistor, a second transistor configured to supply a certain current, and a control circuit configured to electrically connect or disconnect the gate of the first transistor to or from a gate of the second transistor via a first resistor. The control circuit may supply, to the gate of the second transistor, an intermediate potential in accordance with the other of the differential data signals, while the gate of the first transistor is electrically disconnected from the gate of the second transistor.

Light emitting element driving circuit

A light-emitting device driving circuit capable of reliably performing emission control on a light-emitting device of a low emission threshold (about 10 mA or less) and capable of correcting a distortion due to the Early effect of a transistor in the drive current supplied to the light emitting device. The light limiting device driving circuit includes a current control unit () which controls the value of a main current based on a control voltage, a bias current source (CC) for subtracting a bias current from the main current, and a switching unit () which controls emission of light from the light-emitting device by switching, based on the drive signal, a current obtained by subtracting the bias current from the main current or a current based on the current obtained by the subtraction.

Driving circuit of driving light-emitting device

There is provided a differential signal comparator which maintains the duty ratio of complementary input signals. The differential signal comparator includes differential amplifier circuitsandreceiving complementary input signals, a plurality of current amplifier circuitstofor amplifying current output from the differential amplifier circuits and a current arithmetic operation circuitfor an arithmetic operation of an output from the plurality of current amplifier circuitstoat the time of converting the differential signal between the complementary input signals into a voltage of CMOS level, wherein a capacitive load of an output of the differential amplifier circuit is constant independent of a level of the input signals. A voltage signal which is current-voltage converted to a complementary CMOS level signal is input into a differential comparator to obtain a single end CMOS level signal.

Differential signal comparator

Gradation is improved in image formation by image-forming apparatus employing a light emitting elements such as organic light-emitting element, and image quality. A light-emitting element is provided in which the emission and no emission of light is controlled by the intensity of the input signal from the scanning line and the signal line by flowing constant electric current to a two-input-differential connection circuit one of which is connected to the light-emitting element.

Driving circuit of active matrix type light-emitting element

A light-emitting element and a picture signal current supply circuit are formed near each of the crossings of scan lines and signal lines and a charging circuit is provided to precharge the electric capacitance of the light-emitting element with an electric load that is lower than the light-emitting threshold level of the element. With this arrangement, the time that needs to be spent before the light-emitting element, which is an organic EL element, starts emitting light is reduced so that it can be driven at high speed to display an image with tones.

Drive circuit to be used in active matrix type light-emitting element array

Drive circuit for active matrix light emitting device

This invention includes a current output sensor, and a current AD conversion means which is connected to the output side of the current output sensor and has a current mirror circuit arranged on the input side of a comparator in order to directly A/D-convert an output from the current output sensor. A signal can be stably processed with a small circuit scale and low current consumption.

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Atsugi, Japan

Hiroyuki Nakamura