Abstract: A current driving device comprises; a three-terminal regulator configuration circuit operative as a three-terminal regulator which drops a voltage of a first electric power supply to a predetermined target output voltage in a state where a main terminal and a control terminal of a power transistor are connected to a main terminal connection terminal and a control terminal connection terminal, respectively; a voltage setting circuit which sets a control voltage corresponding to a target output voltage which is applied from the three-terminal regulator configuration circuit to the control terminal of the power transistor; and a voltage restricting circuit which is connected to the control terminal connection terminal and controls the control voltage applied to the control terminal of the power transistor so that the output voltage of the three-terminal regulator configuration circuit becomes a predetermined voltage or less, upon being supplied with the electric power from the first electric power supply.

Abstract: A current summing type D/A converter having a configuration of two or more steps is provided. In a D/A converter block of the first step, by adding current segments, upper bits are D/A converted, and one of the current segments in the first step is further supplied to a D/A converter block in a second step to be shunt by the D/A converter block in the second step, so that lower bits are D/A converted. The output current in the first step and the output current in the second step are then added each other. According to the foregoing method, the D/A conversion may be performed without causing a differential linearity error.

Abstract: A current summing type D/A converter having a configuration of two or more steps is provided. In a D/A converter block of the first step, by adding current segments, upper bits are D/A converted, and one of the current segments in the first step is further supplied to a D/A converter block in a second step to be shunt by the D/A converter block in the second step, so that lower bits are D/A converted. The output current in the first step and the output current in the second step are then added each other. According to the foregoing method, the D/A conversion may be performed without causing a differential linearity error.

Abstract: A laser diode driving device of the present invention can appropriately shorten the rising time and the falling time of a laser diode drive current in a range from a small current region to a large current region. In synchronization with the addition of an original input current from an input constant current source to the laser diode drive current amplifier, a differentiated current is added to the input current through a differentiation circuit and a pull-in type V-I conversion circuit, whereby the rising of a laser diode drive current is made abrupt. Furthermore, by increasing a gate potential of an input PchMOS transistor constituting the laser diode drive current amplifier by a differentiation circuit and a push-out type V-I conversion circuit in synchronization with the disconnection of an input current, the falling of a laser diode drive current is made abrupt.

Abstract: In order to improve the robustness against electrostatic discharge, when power source terminal and ground terminal are open, of a semiconductor device having a first, a second and a third inverter that are connected in a cascade arrangement, the semiconductor device is provided not only with a first input protection circuit for guiding positive electrostatic discharges, that are applied from outside to a signal input terminal, to a power source line, and a second input protection circuit for guiding negative electrostatic discharges, that are applied from outside to the signal input terminal, to a ground line, but also an internal protection circuit for guiding electrostatic discharges that have been guided by the first input protection circuit to the power source line and flow from a P-channel MOS transistor in the second inverter towards the third inverter, to the ground line.

Abstract: In order to improve the robustness against electrostatic discharge, when power source terminal and ground terminal are open, of a semiconductor device having a first, a second and a third inverter that are connected in a cascade arrangement, the semiconductor device is provided not only with a first input protection circuit for guiding positive electrostatic discharges, that are applied from outside to a signal input terminal, to a power source line, and a second input protection circuit for guiding negative electrostatic discharges, that are applied from outside to the signal input terminal, to a ground line, but also an internal protection circuit for guiding electrostatic discharges that have been guided by the first input protection circuit to the power source line and flow from a P-channel MOS transistor in the second inverter towards the third inverter, to the ground line.

Abstract: In order to improve the robustness against electrostatic discharge, when power source terminal and ground terminal are open, of a semiconductor device having a first, a second and a third inverter that are connected in a cascade arrangement, the semiconductor device is provided not only with a first input protection circuit for guiding positive electrostatic discharges, that are applied from outside to a signal input terminal, to a power source line, and a second input protection circuit for guiding negative electrostatic discharges, that are applied from outside to the signal input terminal, to a ground line, but also an internal protection circuit for guiding electrostatic discharges that have been guided by the first input protection circuit to the power source line and flow from a P-channel MOS transistor in the second inverter towards the third inverter, to the ground line.

Abstract: A laser diode driving device of the present invention can appropriately shorten the rising time and the falling time of a laser diode drive current in a range from a small current region to a large current region. In synchronization with the addition of an original input current from an input constant current source to the laser diode drive current amplifier, a differentiated current is added to the input current through a differentiation circuit and a pull-in type V-I conversion circuit, whereby the rising of a laser diode drive current is made abrupt. Furthermore, by increasing a gate potential of an input PchMOS transistor constituting the laser diode drive current amplifier by a differentiation circuit and a push-out type V-I conversion circuit in synchronization with the disconnection of an input current, the falling of a laser diode drive current is made abrupt.

Abstract: The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value.

Abstract: In order to improve the robustness against electrostatic discharge, when power source terminal and ground terminal are open, of a semiconductor device having a first, a second and a third inverter that are connected in a cascade arrangement, the semiconductor device is provided not only with a first input protection circuit for guiding positive electrostatic discharges, that are applied from outside to a signal input terminal, to a power source line, and a second input protection circuit for guiding negative electrostatic discharges, that are applied from outside to the signal input terminal, to a ground line, but also an internal protection circuit for guiding electrostatic discharges that have been guided by the first input protection circuit to the power source line and flow from a P-channel MOS transistor in the second inverter towards the third inverter, to the ground line.

Abstract: The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value.

Abstract: The laser drive device of this invention includes a laser, first and second current sources, a current amplifier, and first and second transistors. When the first transistor is OFF, a first current from the first current source is supplied to the current amplifier, where the current is amplified to generate a laser current to be supplied to the laser. Thus, the laser is turned ON. During this time, the second transistor is ON, allowing a second current to flow from a power supply node into the second current source. When the first transistor is ON, the entire or part of the first current flows into the second current source through the first transistor. This reduces the current supplied to the current amplifier and thus the laser current, resulting in turning OFF the laser. During this time, the second transistor is OFF. The values of the first and second currents are determined by a set current value.

Abstract: The digital-analog converter circuit includes: a high-order D-A converter circuit unit (100) for outputting a first voltage (Va) and a second voltage (Vb) both resulting from D-A conversion of the high-order five bits of a 13-bit input code to first and second output nodes (11, 12) through two buffers (10a, 10b) having the same characteristics, respectively; a low-order D-A converter circuit unit (200) for receiving the voltages on these two output nodes as reference voltages of an R-2R ladder circuit (201) and conducting D-A conversion of the low-order eight bits of the input code for output to a third output node (13); a sample-and-hold unit (250) for selectively sampling and holding the voltage on the third output node (13), i.e., the D-A conversion output of the 13-bit input code, according to a value of the input code; and an output unit (300) for multiplying the sampled and held D-A conversion output voltage by a gain with respect to an arbitrary central voltage.

Abstract: In an optical disc apparatus, a semiconductor SLD driving device is mounted on an optical pickup in order to realize a high speed switching of drive current for a semiconductor laser diode (SLD), necessary for recording data. The SLD is placed. within 5 cm from the SLD driving device. The driving device becomes a heat source due to driving current of the SLD, and increases a temperature of the optical pickup. Since the temperature rises proportionally to power consumption, power saving is required. A voltage supplied to the driving device is controlled to be a minimum level necessary for keeping the driving device still working on basic functions. The SLD driving device is mounted to the optical pickup, and this driving device handles N pieces of input signals for setting semiconductor laser power and N pieces of switch-timing-input-signals for selecting respective input signals.