Abstract: In a power supply apparatus that is so configured as to produce from an input voltage an output voltage Vo within a predetermined permissible variation range, the output voltage Vo is so controlled as to decrease within the permissible variation range as the output current Io increases.

Abstract: In a power supply apparatus that is so configured as to produce from an input voltage an output voltage Vo within a predetermined permissible variation range, the output voltage Vo is so controlled as to decrease within the permissible variation range as the output current Io increases. This configuration offers an output voltage with an improved transient characteristic against an abrupt variation in the output current and simultaneously permits reduction of the power consumed when the output current increases.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.

Abstract: A semiconductor device has an electrostatic protection diode in a signal input portion thereof and is accompanied by a parasitic transistor between the diode and an output control transistor. The semiconductor device further has a dummy transistor that is formed closer than the output control transistor to the electrostatic protection diode, and an output logic determining circuit that keeps the output signal at a predetermined logic level so long as the parasitic transistor formed between the electrostatic protection diode and the dummy transistor is on. With this configuration, malfunctioning caused by a parasitic transistor can be prevented without the use of an externally fitted component.

Abstract: In a DC/DC converter having a plurality of DC/DC converters, to prevent faults in the circuit and the circuit elements constituting it even when the balance of current limiting operation among the individual DC/DC converters is disturbed due to individual and temperature-related variations in the characteristics of the circuit elements, the output currents of the individual DC/DC converters are detected and added together, and are limited individually so that their sum does not exceed a predetermined level of current.

Abstract: A power supply unit (system power supply IC) has a multiplicity of power supply circuits providing for different supply voltages. Should an abnormal condition take place in any of the multiple power supply circuits, the power supply circuit suffering the abnormality issues an abnormality detection signal that contains a power supply circuit number and an abnormality type, which signal is stored in a nonvolatile memory together with time data indicative of the time of reception of the abnormality detection signal before all the power supply circuits are disabled. Thus, this arrangement protects the system power supply IC and the loads connected thereto, and provides convenient means for analyzing the abnormality and replicating it if necessary, based on the abnormal power supply circuit number, abnormality type and time data stored in the nonvolatile memory.

Abstract: A switching device driving apparatus has a driver for controlling, according to an input signal, the on/off states of a pair of field-effect transistors connected in series between a first supply voltage and a second supply voltage lower than the first supply voltage, and a detector for detecting the on/off states of body diodes attached respectively to the field-effect transistors. Only after either of the body diodes is detected being on are the field-effect transistors respectively turned on to produce an output corresponding to the input signal. This makes it possible to securely prevent the two FETs from being turned on simultaneously independently of their characteristics and type.

Abstract: A switching power supply unit generates a pulse signal having a duty factor based on the voltage associated with the difference between a reference voltage and the output voltage of the unit, and the voltage associated with the current flowing through a smoothing coil. Upon receipt of the pulse signal and a light-load determination signal, a delay-control unit of the power supply unit outputs as an instruction signal supplied to the switching circuit the pulse signal as it is when the light-load determination signal indicates that the load is not light, but otherwise outputs the pulse signal after delaying and widening the pulse width thereof. Thus, when the load is light, the switching power supply unit may hold its switching frequency substantially low and constant without rendering the frequency bursting discontinuously.

Abstract: A motor driving apparatus which includes a pair of field-effect transistors connected in series between a first supply voltage and a second supply voltage lower than the first supply voltage, an output smoothing circuit connected to a node between the two field-effect transistors, a driver for controlling on/off states of the field-effect transistors according to an input signal, and a detector for detecting on/off states of body diodes attached respectively to the field-effect transistors. Only after either of the body diodes is detected being on are the field-effect transistors respectively turned on to produce an output corresponding to the input signal so as to eventually produce a desired output voltage from the first supply voltage.

Abstract: A DC/DC converter produces from an input voltage a desired output voltage by first finding the error voltage between the output voltage and a first reference voltage and then controlling the output current according to the differential voltage between the error voltage and a second reference voltage. Used as the first reference voltage is whichever of a variable reference voltage and a first constant reference voltage is lower, and used as the second reference voltage is whichever of the variable reference voltage and a second constant reference voltage is lower. With this circuit configuration, an overshoot or undershoot in the output voltage can be prevented or reduced.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.

Abstract: In a multiphase DC/DC converter having a plurality of DC/DC converters, to prevent faults in the circuit and the circuit elements constituting it even when the balance of current limiting operation among the individual DC/DC converters is disturbed due to individual and temperature-related variations in the characteristics of the circuit elements, the output currents of the individual DC/DC converters are detected and added together, and are limited individually so that their sum does not exceed a predetermined level of current.

Abstract: A power supply device has a reference voltage generator for generating a reference voltage, a monitor voltage generator for generating a monitor voltage that varies according to an output voltage, an output controller for producing the output voltage from an input voltage in such a way that the monitor voltage is kept equal to the reference voltage and then supplying the output voltage to a load, and a reference voltage adjuster for varying the reference voltage according to the monitor voltage. This makes it possible to reduce, with a simple configuration, variation in the output voltage resulting from variation in the power source or the load.

Abstract: The power supply unit is provided with a power supply circuit adapted to generate an output voltage in accord with an instruction voltage, an output condenser Co connected to the output end of the power supply circuit, and an auxiliary output voltage setting circuit adapted to compare the instruction voltage and the output voltage and to cause the output condenser to discharge its electric charge when the instruction voltage becomes lower than the output voltage. Because of the auxiliary output voltage setting circuit, the power supply circuit quickly generates an output voltage in accord with the instruction voltage if the instruction voltage is lowered.

Abstract: In a multiphase DC/DC converter having a plurality of DC/DC converters, to prevent faults in the circuit and the circuit elements constituting it even when the balance of current limiting operation among the individual DC/DC converters is disturbed due to individual and temperature-related variations in the characteristics of the circuit elements, the output currents of the individual DC/DC converters are detected and added together, and are limited individually so that their sum does not exceed a predetermined level of current.

Abstract: A switching power supply unit generates a pulse signal having a duty factor based on the voltage associated with the difference between a reference voltage and the output voltage of the unit, and the voltage associated with the current flowing through a smoothing coil. Upon receipt of the pulse signal and a light-load determination signal, a delay-control unit of the power supply unit outputs as an instruction signal supplied to the switching circuit the pulse signal as it is when the light-load determination signal indicates that the load is not light, but otherwise outputs the pulse signal after delaying and widening the pulse width thereof. Thus, when the load is light, the switching power supply unit may hold its switching frequency substantially low and constant without rendering the frequency bursting discontinuously.

Abstract: A switching power supply unit generates a pulse signal having a duty factor based on the voltage associated with the difference between a reference voltage and the output voltage of the unit, and the voltage associated with the current flowing through a smoothing coil. Upon receipt of the pulse signal and a light-load determination signal, a delay-control unit of the power supply unit outputs as an instruction signal supplied to the switching circuit the pulse signal as it is when the light-load determination signal indicates that the load is not light, but otherwise outputs the pulse signal after delaying and widening the pulse width thereof. Thus, when the load is light, the switching power supply unit may hold its switching frequency substantially low and constant without rendering the frequency bursting discontinuously.

Abstract: A semiconductor device has an electrostatic protection diode in a signal input portion thereof and is accompanied by a parasitic transistor between the diode and an output control transistor. The semiconductor device further has a dummy transistor that is formed closer than the output control transistor to the electrostatic protection diode, and an output logic determining circuit that keeps the output signal at a predetermined logic level so long as the parasitic transistor formed between the electrostatic protection diode and the dummy transistor is on. With this configuration, malfunctioning caused by a parasitic transistor can be prevented without the use of an externally fitted component.

Abstract: In a power supply apparatus that is so configured as to produce from an input voltage an output voltage Vo within a predetermined permissible variation range, the output voltage Vo is so controlled as to decrease within the permissible variation range as the output current Io increases.

Abstract: A DC/DC converter produces from an input voltage a desired output voltage by first finding the error voltage between the output voltage and a first reference voltage and then controlling the output current according to the differential voltage between the error voltage and a second reference voltage. Used as the first reference voltage is whichever of a variable reference voltage and a first constant reference voltage is lower, and used as the second reference voltage is whichever of the variable reference voltage and a second constant reference voltage is lower. With this circuit configuration, an overshoot or undershoot in the output voltage can be prevented or reduced.