Mitsumi Electric Company Ltd.

Heisuke Nakashima

Fumihiro Inoue

Kenji Mitsuhira

A DC-DC converter, which allows a current to pass through an inductor and rectifies the current through the inductor to convert an input direct current voltage supplied from a direct current power unit into a direct current voltage at a different potential and output the direct current voltage, includes a switching control circuit performing peak-current control procedures including turning on the switching element when the converted direct current voltage drops to a predetermined potential and turning off the switching element when the current through the inductor reaches a predetermined value. The converter includes a copied-current generating circuit generating a current proportional to the output current. The switching control circuit turns off the switching element when the circuit detects that the current through the inductor reaches a predetermined value with reference to a combined current of the copied current generated at the copied-current generating circuit and a predetermined reference current.

DC-DC converter and load-driving semiconductor integrated circuit

A ripple-control switched-mode power supply includes a control circuit to switch on/off a drive switching element. The control circuit includes a simulated voltage generation circuit that smoothes a voltage at a node connecting the drive switching element and an inductor and that generates a simulated voltage corresponding to an output voltage; a timer that measures a time corresponding to an input voltage and the simulated voltage; a voltage comparison circuit that compares a feedback voltage and a predetermined voltage; and a control pulse generation circuit that generates a control pulse having a pulse width corresponding to the time based on outputs from the timer and the voltage comparison circuit. The control circuit varies the pulse width of the control pulse in accordance with a variation in the input voltage to maintain a constant switching cycle.

Switched-mode power supply having an adaptive on-time function and controlling output with a ripple control method

Disclosed is a switched-mode power supply including an inductor which is connected between a voltage input terminal to which a DC voltage is input and an output terminal to which a load is connected, a driver switching element which intermittently feeds a current to the inductor and a control circuit which generates a control pulse according to a feedback voltage from output side and controls on/off of the driver switching element. The control circuit includes a voltage comparison circuit which compares the feedback voltage to a predetermined voltage and a pseudo ripple generator circuit which generates a pseudo ripple voltage having a predetermined amplitude, and the control circuit injects a ripple component in a transmission path of the feedback voltage based on the pseudo ripple voltage generated by the pseudo ripple generator circuit.

Switched-mode power supply

Disclosed is a switching-mode power supply device which outputs a voltage having a different electrical potential from an input voltage including an inductor, a driving switching element and a control circuit, and the control circuit includes a trigger signal generating circuit which generates and outputs a signal which provides timing to turn the driving switching element on or off, a first timekeeping unit which times a fixed ON period or a fixed OFF period which defines the pulse width of a driving pulse of the driving switching element, a second timekeeping unit which times a minimum OFF period or a minimum ON period of the driving switching element and a sudden load change detection circuit which detects a sudden load change.

PFM SMPS with quick sudden load change response

A control technology which eliminates the need for changing the switching frequency even under light load where the on-time of a drive switching element becomes shorter than a minimum on-time dependent on the characteristics of the circuit in a synchronous rectification switching regulator. The synchronous rectification switching regulator includes a drive switching element for storing energy in a coil by applying a DC input voltage from a DC power supply to an inductor and permitting a current to flow, and a rectification switching element for rectifying the current of the inductor during an energy discharge period where the drive switching element is turned off. The timing for turning off the rectification switching element under light load is delayed so as to store energy in the inductor from the output, and the on-time is controlled to become longer as the load becomes lighter by the output from an error amplifier.

DC-DC converter and semiconductor integrated circuit for controlling power source

In a current resonance type multi-phase DC/DC converting apparatus for combining, using an output capacitor, M converter output voltages produced by M current resonance type multi-phase DC/DC converters connected in parallel to each other to produce an output voltage, each of the M current resonance type multi-phase DC/DC converters has N current resonance type DC/DC converters connected in parallel with one another. The N current resonance type DC/DC converters have N resonance circuits, respectively. Each of the M current resonance type multi-phase DC/DC converters shares a resonance inductor of the N resonance circuits.

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Tama, Japan

Heisuke Nakashima