Abstract: A semiconductor integrated circuit device has a p-type substrate to which a ground voltage is applied and a floating-type NMOSFET which is integrated on the p-type substrate and to which a negative voltage lower than the ground voltage is applied. The floating-type NMOSFET includes an n-type buried layer buried in the p-type substrate, a high voltage n-type well formed on the n-type buried layer and floats electrically, a p-type drift region formed in the n-type well, an n-type drain region and an-type source region formed in the p-type drift region, and a gate electrode formed on a channel region interposed between the n-type drain region and the n-type source region. The high voltage n-type well includes an n-type tunnel region, with a higher impurity concentration than that of the high voltage n-type well, inside a peripheral region formed so as to surround the p-type drift region.

Abstract: A semiconductor integrated circuit device has a p-type substrate to which a ground voltage is applied and a floating-type NMOSFET which is integrated on the p-type substrate and to which a negative voltage lower than the ground voltage is applied. The floating-type NMOSFET includes an n-type buried layer buried in the p-type substrate, a high voltage n-type well formed on the n-type buried layer and floats electrically, a p-type drift region formed in the n-type well, an n-type drain region and an-type source region formed in the p-type drift region, and a gate electrode formed on a channel region interposed between the n-type drain region and the n-type source region. The high voltage n-type well includes an n-type tunnel region, with a higher impurity concentration than that of the high voltage n-type well, inside a peripheral region formed so as to surround the p-type drift region.

Abstract: An SPM driver drives a spindle motor. A VCM driver drives a VCM. A DC/DC converter (switching regulator) receives a power supply voltage from an external circuit, and generates a stabilized voltage. Linear regulators each receive a power supply voltage from an external circuit, and each generates a stabilized voltage. A shock detection circuit detects vibration of a device mounting the driving circuit. A power monitoring circuit monitors the power supply voltage, and generates a power-on reset signal which is switched to a predetermined level whenever the power supply voltage is cut off. An ADC converts the back electromotive voltage that occurs at the VCM into a digital signal. A serial interface receives data from an external host processor, which is used to control the driving circuit. Cutoff circuits are arranged between the capacitors, which are to be charged using the induced current that occurs at the SPM, and the power supply terminal.

Abstract: A sampling circuit samples, while running a motor at a predetermined rotational speed, over a predetermined period a back electro-motive force induced at one end of at least one phase coil, with one end of each phase coil of the motor being brought to a high impedance. A waveform data generating circuit holds as waveform data SIN the back electro-motive force beforehand sampled by the sampling circuit. A PWM signal generating circuit sequentially reads the waveform data SIN from the waveform data generating circuit to generate a PWM signal Spwm, the pulse width of which is modulated.

Abstract: An SPM driver drives a spindle motor. A VCM driver drives a VCM. A DC/DC converter (switching regulator) receives a power supply voltage from an external circuit, and generates a stabilized voltage. Linear regulators each receive a power supply voltage from an external circuit, and each generates a stabilized voltage. A shock detection circuit detects vibration of a device mounting the driving circuit. A power monitoring circuit monitors the power supply voltage, and generates a power-on reset signal which is switched to a predetermined level whenever the power supply voltage is cut off. An ADC converts the back electromotive voltage that occurs at the VCM into a digital signal. A serial interface receives data from an external host processor, which is used to control the driving circuit. Cutoff circuits are arranged between the capacitors, which are to be charged using the induced current that occurs at the SPM, and the power supply terminal.

Abstract: A sampling circuit samples, while running a motor at a predetermined rotational speed, over a predetermined period a back electro-motive force induced at one end of at least one phase coil, with one end of each phase coil of the motor being brought to a high impedance. A waveform data generating circuit holds as waveform data SIN the back electro-motive force beforehand sampled by the sampling circuit. A PWM signal generating circuit sequentially reads the waveform data SIN from the waveform data generating circuit to generate a PWM signal Spwm, the pulse width of which is modulated.

Abstract: A power supply apparatus may include a plurality of power supply circuits, an individual soft start circuit including a first terminal for outputting a predetermined fixed voltage and a second terminal for outputting a voltage that varies with time, and an individual soft start switch. The individual soft start circuit may be operated when any of the plurality of supply voltages output from the power supply circuits is caused to make a transition individually. The individual soft start switch may connect the power supply circuit with the first terminal or the second terminal of the individual soft start circuit. The plurality of power supply circuits may apply soft start control to the respective supply voltages in accordance with the soft start voltage output from the individual soft start circuit.

Abstract: A power supply apparatus may include a plurality of power supply circuits, an individual soft start circuit including a first terminal for outputting a predetermined fixed voltage and a second terminal for outputting a voltage that varies with time, and an individual soft start switch. The individual soft start circuit may be operated when any of the plurality of supply voltages output from the power supply circuits is caused to make a transition individually. The individual soft start switch may connect the power supply circuit with the first terminal or the second terminal of the individual soft start circuit. The plurality of power supply circuits may apply soft start control to the respective supply voltages in accordance with the soft start voltage output from the individual soft start circuit.

Abstract: A power supply apparatus includes a plurality of power supply circuits, switches connected to the power supply circuits, a common soft start circuit and an individual soft start circuit commonly connected to the plurality of power supply circuits via the switches. The power supply circuits are commonly connected to the common soft start circuit at power-on or power-off so as to perform common soft start by the common soft start circuit. When a voltage from any of the plurality of power supply circuits is caused to make a transition individually, the associated power supply circuit is connected to the individual soft start circuit so as to perform soft start by the individual soft start circuit.

Abstract: In a load driving circuit, a detection current Is (=Io/N), 1/N of a driving current Io, flows in a detection resistor, where N indicates a shunt ratio between a current (=driving current Io) that flows in an output source (S1) and a current (=detection current Is) that flows in a detection source (S2). The shunt ratio is determined by a cell ratio between the output source (S1) and the detection source (S2).

Abstract: The sensorless motor driving apparatus according to the invention may include: a timing generation circuit generating a timing signal at intervals T; a driving signal generation circuit receiving the timing signal and generating, at the intervals T, pulse signals, the number of which M (=m×L+k) is defined by a sum of a predetermined number k and a product of the number of statuses L of the rotor and an integer (m) equal to or greater than 1; and an amplitude control circuit switching between commutation patterns of the driving signal in synchronization with the pulse signals.

Abstract: A power supply apparatus includes a plurality of power supply circuits, switches connected to the power supply circuits, a common soft start circuit and an individual soft start circuit commonly connected to the plurality of power supply circuits via the switches. The power supply circuits are commonly connected to the common soft start circuit at power-on or power-off so as to perform common soft start by the common soft start circuit. When a voltage from any of the plurality of power supply circuits is caused to make a transition individually, the associated power supply circuit is connected to the individual soft start circuit so as to perform soft start by the individual soft start circuit.

Abstract: In a load driving circuit, a detection current Is (=Io/N), 1/N of a driving current Io, flows in a detection resistor, where N indicates a shunt ratio between a current (=driving current Io) that flows in an output source (S1) and a current (=detection current Is) that flows in a detection source (S2). The shunt ratio is determined by a cell ratio between the output source (S1) and the detection source (S2).

Abstract: The sensorless motor driving apparatus according to the invention includes: a timing generation circuit generating a timing signal at intervals T; a driving signal generation circuit receiving the timing signal and generating, at the intervals T, pulse signals, the number of which M (=m×L+k) is defined by a sum of a predetermined number k and a product of the number of statuses L of the rotor and an integer (m) equal to or greater than 1; and an amplitude control circuit switching between commutation patterns of the driving signal in synchronization with the pulse signals.

Abstract: A motor driving device for keeping the rotation speed of a spindle motor has a detector for detecting the rotation rate of the motor and a circuit for producing an error voltage that represents the error of the detected rotation rate from the specified rotation rate. In accordance with the error voltage, the amplitude of the driving signal of the motor is controlled. As the error voltage becomes lower, the amplitude of the driving signal is increased to supply more current to the motor. To prevent an overcurrent through the motor, a current limiter circuit is provided. When the error voltage is lower than the current limit voltage output from the current limiter circuit, the driving signal is controlled in accordance with the current limit voltage instead of the error voltage. The current limiter circuit is so configured that the current limit voltage does not vary with temperature.