Fuji Electric Co., Ltd.

Ryuji Yamada

Ryuunosuke Araumi

Satoru Fujita

Kazuaki Mino

Koji Kawaguchi

Qichen Wang

Manabu Takei

Koji Maruyama

Hideyo Nakamura

Takaaki Tanaka

Takashi Kuwabara

Takato Sugawara

Hiromu Takubo

Ryuji Shimizu

Nobuyuki Tawada

Kazuyuki Yoda

Hirokazu Kadoi

Hiroyuki Oguchi

A switching control circuit for a power supply circuit including first and second inductors, and first and second transistors controlling first and second inductor currents flowing through the first and second inductors, respectively. The switching control circuit includes: a detection circuit detecting a switching period of the first transistor and a time difference between first and second timings, at which the first and second inductor currents respectively reach first and second predetermined values; an error output circuit outputting an error between a predetermined ratio and a ratio of the time difference to the switching period; and a driving signal output circuit configured to output a driving signal to turn on the second transistor, after the second inductor current reaches the second predetermined value, and to turn off the second transistor, in response to a second time period according to the first time period and the error having elapsed.

Switching control circuit, control circuit, and power supply circuit

A switching control circuit for a power supply circuit that includes an inductor configured to receive a rectified voltage corresponding to an alternating current (AC) voltage, and a transistor configured to control a current flowing through the inductor, the power supply circuit generating an output voltage from the AC voltage, the switching control circuit being configured to switch the transistor. The switching control circuit comprises: a signal output circuit configured to output a signal to turn on the transistor, after lapse of a first time period since the inductor current reaches a first predetermined value after the transistor is turned off, the first time period corresponding to a conduction period during which a parasitic diode of the transistor conducts; and a driver circuit configured to turn on the transistor based on the signal, and turn off the transistor, based on a feedback voltage corresponding to the output voltage.

Switching control circuit and power supply circuit

An integrated circuit for a power supply circuit, including: a first command value output circuit outputting a first command value to turn on a transistor of the power supply circuit for a first time period; an on signal output circuit outputting an on signal to turn on the transistor; a delay circuit delaying the on signal by a predetermined time period; a correction circuit correcting the first command value, to output a second command value to turn on the transistor for a second time period; and a driver circuit turning on and off the transistor based respectively on the delayed on-signal and the second command value. The correction circuit corrects the first command value based on the predetermined time period and a ratio between the second time period and another time period from when the transistor is turned off to when an inductor current of the power supply circuit reaches a predetermined value.

Integrated circuit and power supply circuit

A switching control circuit for a power supply circuit, including: a first command value output circuit outputting a first command value; a correction circuit correcting the first command value, to output a second command value; a first timer circuit measuring a first time period starting from a first timing at which a transistor of the power supply circuit is turned on; and a driving signal output circuit outputting a driving signal to turn on the transistor in response to an inductor current of the power supply circuit reaching a predetermined value and the first time period having elapsed since the first timing, and outputting the driving signal to turn off the transistor based on the second command value. The correction circuit causes an on time period of the transistor to increase, when the first time period has elapsed since the first timing, after the inductor current reaches the predetermined value.

A current detection circuit configured to detect a resonant current of a power supply circuit. The power supply circuit includes a resonant circuit that has an inductor and a first capacitor having a first end and a second end. The current detection circuit includes a second capacitor having a first end and a second end, and a non-linear circuit provided between the second end of the second capacitor and the second end of the first capacitor. The first end of the second capacitor is coupled to the first end of the first capacitor.

Current detection circuit including non-linear circuit and power supply circuit containing the same

A switching control circuit controls switching of a switching device, which controls a resonance current of a resonant converter, with a frequency corresponding to an output voltage of the resonant converter. The switching control circuit includes a detection circuit configured to detect a difference between a first timing at which the switching device is turned on and a second timing at which a polarity of the resonance current reverses, and a signal output circuit configured to output a driving signal with a preset minimum frequency, responsive to the difference becoming so small as to satisfy a predetermined condition.

Switching control circuit and resonant converter

A switching control circuit for a power supply circuit that generates an output voltage from an AC voltage. The power supply circuit includes a rectifier circuit rectifying the AC voltage, an inductor receiving the rectified AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, based on the inductor current and the output voltage. The switching control circuit includes a target value output circuit that outputs a target value of a peak value of the inductor current for shaping a waveform of the peak value so as to be similar to a waveform of the rectified voltage, and a drive signal output circuit that outputs a drive signal to turn on the transistor upon the inductor current falling below a predetermined value and turn off the transistor upon the peak value of the inductor current reaching the target value.

Switching control circuit and power factor correction circuit

A switching control circuit for controlling a power supply circuit that includes an inductor receiving a rectified voltage corresponding to an AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, and includes an output circuit, a processing circuit and a drive signal output circuit. The output circuit sequentially receives a first voltage, which fluctuates at a frequency twice a frequency of the AC voltage, and outputs, as a second voltage, the received first voltage after a delay of a predetermined period of time. The processing circuit processes the first voltage based on a value corresponding to the second voltage, to remove a ripple component generated in an output voltage and contained in the first voltage. The drive signal output circuit outputs a drive signal for driving the transistor, in response to a processing result of the processing circuit.

A switching control circuit for controlling an LLC converter that includes a first switching device, a first free-wheeling diode connected in parallel with the first switching device, a second switching device connected in series with the first switching device and the first free-wheeling diode, and a second free-wheeling diode connected in parallel with the second switching device. The switching control circuit controls switching of the first and second switching devices. The switching control circuit includes a determination circuit determining whether an operation mode of the LLC converter is a first mode or a second mode based on the resonant current of the LLC converter, and a drive signal output circuit outputting first and second drive signals for respectively switching the first and second switching devices based on the determined operation mode, to thereby prevent a shoot-through current from flowing through the first switching device or the second switching device.

Switching control circuit and LLC converter

A snubber apparatus includes N parallel charge paths, each of which has a positive-side capacitor, a first diode, and a negative-side capacitor sequentially connected in series between a positive-side terminal and a negative-side terminal, and that allows current to flow from the positive-side terminal's side to the negative-side terminal's side. The snubber apparatus includes N+1 parallel discharge paths, each of which has a second diode connected between the negative-side terminal or the negative-side capacitor in the k-th charge path of the N charge paths, and the positive-side capacitor in the (k+1)-th charge path of the N charge paths or the positive-side terminal, and that allows current to flow from the negative-side terminal's side to the positive-side terminal's side via at least one of the negative-side capacitor and the positive-side capacitor. At least one of the charge paths has a plurality of sections that are turned and adjacent to each other.

Snubber apparatus and power conversion apparatus

A switching control circuit that controls switching of a switching device, the switching control circuit includes a frequency modulation circuit that generates an oscillator signal, and modulates a frequency of an oscillator signal with a predetermined frequency and a modulation index of two or more, and a drive circuit that drives the switching device in response to a signal corresponding to the modulated oscillator signal, the predetermined frequency being higher than a frequency indicative of a value that is a quarter of a half width of a bandpass filter used for measuring noise generated when the switching device is driven.

A power conversion device includes a transformer, and a first bridge circuit connected to a primary-side of the transformer and capable of switching a polarity of a connection between a pair of DC bus bars on the primary-side and the transformer. A second bridge circuit is connected to a secondary-side of the transformer and capable of switching a polarity of a connection between a pair of DC bus bars on the secondary-side and the transformer. A control device is provided which is capable of performing control of switching the first bridge circuit and the second bridge circuit with a phase difference. The control device has a frequency adjustment unit for adjusting a frequency of switching of the first bridge circuit and the second bridge circuit, according to an output from the first bridge circuit or the second bridge circuit and a target value.

Power conversion device, control method, and computer-readable medium

A snubber module is provided, which constitutes a snubber apparatus attachable to a terminal of a semiconductor module. The snubber module includes: a positive-side capacitor, a first diode and a negative-side capacitor sequentially connected between a positive-side snubber terminal and a negative-side snubber terminal, the positive-side snubber terminal connectable to a positive-side terminal of the semiconductor module, and the negative-side snubber terminal connectable to a negative-side terminal of the semiconductor module; a first coupling terminal directly or indirectly connected to one node of either a first node between the positive-side capacitor and the first diode or a second node between the negative-side capacitor and the first diode; and a housing accommodating the positive-side capacitor, the negative-side capacitor and the first diode, and having provided therein the positive-side snubber terminal, the negative-side snubber terminal and the first coupling terminal in a manner enabling external connection.

Snubber module, snubber apparatus and power conversion apparatus

A snubber device to be mounted to a terminal of a semiconductor module is provided. The snubber device includes n (n: integer of 1 or greater) parallel charge paths each having a positive-side capacitor, a first diode, and a negative-side capacitor sequentially connected in series between positive-side and negative-side terminals of the semiconductor module, and configured to enable current to flow from the positive-side terminal toward the negative-side terminal; and (n+1) parallel discharge paths each of which having a second diode connected between the negative-side terminal or the negative-side capacitor of an Ncharge path (N: integer within a range of 0&#x2264;N&#x2264;n) of then charge paths and the positive-side capacitor of a (N+1)charge path of the n charge paths or the positive-side terminal, and configured to enable current to flow from the negative-side terminal toward the positive-side terminal via at least one of the negative-side and positive-side capacitors.

Snubber device and power conversion apparatus

An integrated circuit that drives a switching device provided between a first line on a ground side and a second line on a power supply side, when a power supply voltage is applied between a first input terminal connected with a first capacitor and a second input terminal, the first capacitor having one end grounded and another end connected to the first input terminal, the integrated circuit includes: a first terminal connected to a circuit element, the circuit element having one end grounded and another end connected to the first terminal; and a drive circuit that changes a voltage at the first terminal to one logic level when a drive signal of the switching device changes to the one logic level, and changes the voltage at the first terminal to another logic level when the drive signal changes to the other logic level.

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Hachioji, Japan

Ryuji Yamada