Tdk Corporation

Masakazu Takagi

Katsuhiko Shimizu

Toshiyuki Zaitsu

Junichi Yamamoto

Masahiro Gamou

Kenichi Aonuma

A switching power supply unit of the present invention a timing generating circuit () which receives a first control signal formed by a rectifier-transistor driving circuit (), forms a second control signal based on the first control signal, and supplies the second control signal to a control electrode of the rectifier transistor (). The first control signal is synchronized with the switching operation of a half-bridge circuit (), and the second control signal exceeds a threshold voltage of a rectifier transistor () at a timing substantially equal to the timing that one edge of the first control signal is generated and falls below the threshold voltage of the rectifier transistor () at a timing earlier by predetermined time than the timing that the other edge of the first control signal is generated.

Switching power supply unit

A rectifying circuit having a pair of input terminals at which voltage having an AC waveform appears, a plurality of first rectifying elements a plurality of second rectifying elements a first wiring pattern for connecting one of the paired input terminals to the plurality of first rectifying elements and a second wiring pattern for connecting the other of the paired input terminals to the plurality of second rectifying elements In the rectifying circuit, the plurality of first rectifying elements and the plurality of second rectifying elements are laid out so that at least two boundaries between the first and second rectifying elements adjacent to each other are present. With such a layout of the rectifying elements, current flow paths between one of the input terminals and the plurality of first rectifying elements and current flow paths between the other of the input terminals and the plurality of second rectifying elements are closely disposed. Therefore, AC resistance Rac in the first wiring pattern and the second wiring pattern is effectively reduced.

Rectifying circuit and switching power supply device having the same

A multi-stage DC&mdash;DC converter is provided that utilizes multiple loops in the control system to perform stable operation. The multi-stage DC&mdash;DC converter includes: a first DC&mdash;DC converter, a second DC&mdash;DC converter provided as a latter stage to said first DC&mdash;DC converter and a control circuit that controls the switching operation performed by said first DC&mdash;DC converter based on at least the output voltage of said first DC&mdash;DC converter and the output voltage of said second DC&mdash;DC converter. Since the control system is formed with an external loop for feedback of the output voltage of the second DC&mdash;DC converter and an internal loop for feedback of the output voltage of the first DC&mdash;DC converter, the resonance frequencies on the low-frequency side in the transfer function of the entire control system are shifted to higher frequencies than in the case where the control system consists of a single loop, even in cases where stabilization of the control system is difficult with single-loop output voltage feedback control. Accordingly, the frequency at which the phase crosses zero degrees is becomes higher, so the gain margin increases and the operation of the control system can be stabilized.

Multi-stage DC&mdash;DC converter

Switching power supply unit with series connected converter circuits

There is disclosed a synchronized rectifier type switching power source device in which losses and noise generation due to differences in operating delay times in the input and output switching elements can be suppressed. A signal timing adjusting device is provided for controlling the timing of the control signal applied to the first switching device provided in the input side and those of the control signals applied to the second and third switching devices provided in the output side, so that the control signal is applied to the first switching device with a timing delayed as compared with the timings of the control signals applied to the second and third switching devices to thereby compensate for the operating time delay among the first switching device and the second and third switching devices due to the differences in the voltage durability and the current capacity among these switching devices.

Growing community of inventors

Tokyo, Japan

Masakazu Takagi