Ricoh Company, Ltd.

Hiroaki Kyogoku

Tomohiko Kamatani

Nobunari Tsukamoto

Yuji Watabe

Daijiroh Sumino

An ultrasonic sensor includes an ultrasonic transducer; a first voltage output circuit to output a transmission voltage signal that oscillates between a first high voltage and a first low voltage, supplied to a first terminal of the ultrasonic transducer; a reception circuit to detect a voltage signal generated at a second terminal of the ultrasonic transducer; and the second voltage output circuit to output a second high voltage smaller than the first high voltage. The first voltage output circuit includes a first switching unit to perform switching between supplying the transmission voltage signal in ultrasonic transmission; and fixing a potential of the first terminal in ultrasonic reception. The second voltage output circuit includes a second switching unit that performs switching between supplying the second high voltage to the second terminal in ultrasonic transmission; and electrically separating the second voltage output circuit from the second terminal in ultrasonic reception.

Ultrasonic sensor, ultrasonic image generating apparatus, and ultrasonic diagnostic apparatus

A low voltage differential signaling driver includes at least one output circuit, a first control circuit, and a second control circuit. The output circuit includes a first input terminal to receive a first input signal, a second input terminal to receive a second input signal, a first output terminal to output a first output signal, a second output terminal to output a second output signal, and first to sixth transistors. The first control circuit controls a voltage of a control terminal of the first transistor to make a voltage of the first output signal equal to a first reference voltage when the first input signal has a first value. The second control circuit controls a voltage of a control terminal of the second transistor to make the voltage of the first output signal equal to a second reference voltage when the first input signal has a second value.

Low voltage differential signaling driver

A semiconductor laser driver to drive at least one semiconductor laser, the semiconductor laser including a storage device, an emission-intensity setting device, and a drive circuit. The storage device stores emission-intensity switching data to control light-emission intensity of the semiconductor laser, the emission-intensity setting device sets the light-emission intensity based on the emission-intensity switching data stored in the storage device, and, the drive circuit generates a driving current to drive the semiconductor laser based on the light-emission intensity set in the emission-intensity setting device.

Semiconductor laser driver and image forming apparatus incorporating same

A semiconductor laser driver includes a light detection circuit to detect a quantity of light as a detected light emission intensity and output the detected light emission intensity to the control circuit, and a control circuit to control a light emission intensity for the semiconductor laser based on the detected light emission intensity and on a predetermined light emission intensity setting value. The light detection circuit includes a photoelectric conversion element to convert the quantity of light emitted from the semiconductor laser into an electrical current and output the converted electrical current, a current magnification setting circuit to amplify the electrical current output from the photoelectric conversion element to a predetermined amplified current at one of multiple different predetermined magnifications, a detection resistor to convert the amplified current output from the current magnification setting circuit into a voltage and output the voltage as the detected light emission intensity.

A semiconductor laser drive device includes a semiconductor-laser drive element to generate a drive current according to an input control signal to supply the drive current to a semiconductor laser, a control circuit to control the drive current by controlling the semiconductor-laser drive element, and a drive current detection circuit to detect a current value of the drive current supplied to the semiconductor laser and generate a digital control signal representing the detected digital value of the drive current to output.

Semiconductor laser drive device and image forming apparatus incorporating same

A semiconductor laser driver to drive a semiconductor laser, the semiconductor laser includes a drive circuit to generate a drive current to cause the semiconductor laser to emit, and a current control circuit to cause the driving current to repeatedly increase and decrease in a predetermined cycle.

A disclosed laser diode driving device drives laser diodes with driving currents obtained by adding switch currents to corresponding bias currents and includes a common switch current generating circuit configured to generate a common switch current according to an input signal; switch current generating circuits provided for the corresponding laser diodes and configured to generate the switch currents based on the common switch current and input signals; switches configured to control the output of the switch currents to the corresponding laser diodes according to input signals; bias current generating circuits configured to generate the bias currents and output the generated bias currents to the corresponding laser diodes; and a control unit configured to detect the light intensities of the respective laser diodes and to control the common switch current generating circuit, the switch current generating circuits, and the switches to adjust the light intensities of the respective laser diodes.

Laser diode driving device and image forming apparatus including the same

A laser driving circuit configured to drive a semiconductor laser diode, which is less susceptible to noise interference and capable of achieving the control of laser light intensity with high accuracy. Respective circuit components in the laser driving circuit such as an amplifier circuit, a sample hold circuit, a voltage-to-current converter, and a switching circuit are all integrated into an integrated circuit. A capacitor included in the sample hold circuit is further provided as built-in in the integrated circuit, which is previously attached externally. In addition, by changing the resistance of a resistor which is externally connected between the bias current setting terminal of the amplifier circuit and the ground potential by way of a terminal of the integrated circuit, the current outputting capability of the amplifier circuit can be variably adjusted through the adjustment of the charging time of the capacitor. As a result, the response speed of a feedback control loop for controlling the light intensity of laser diode can be increased with less noise interference and high accuracy.

Semiconductor laser driving circuit less susceptible to noise interference

A semiconductor laser driving unit is disclosed that includes a first part generating a bias current; a second part generating a first current for causing the semiconductor laser to emit light, and outputting the first current to the semiconductor laser in accordance with an input control signal; a third part performing initialization to detect a light emission characteristic of the semiconductor laser, and causing the second part to generate a second current of a value obtained from the detected light emission characteristic; and a fourth part causing the second part to generate the first current in which a set offset current is added to the second current. The first part detects the amount of light emission of the semiconductor laser, and generates and outputs the bias current so that the amount of light emission produced by the sum of the bias current and the first current is a predetermined value.

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Hyogo, Japan

Hiroaki Kyogoku