Sanken Electric Co., Ltd.

Akiteru Chiba

Yoichi Kyono

Keita Ishikura

A switching power-supply device, includes a first terminal; a first winding connected to the first terminal; a second winding, which is connected in series to the first winding and is magnetically coupled to the first winding; a first capacitor connected in series to the second winding; a transformer including a primary winding connected in series to the first capacitor and a secondary winding magnetically coupled to the primary winding; a rectifying-and-smoothing circuit connected to the secondary winding; a second terminal, which is connected to an opposite end of the primary winding opposite to a connection end connecting to the first capacitor; a first switching element, which is connected between a connection point of the first winding and the second winding and the second terminal; and a control circuit, which controls first switching element to turn on-and-off.

Switching power-supply device having control circuit controlling switching element to turn on-and-off

Provided is a synchronous rectifier circuit which, even if a synchronous rectification element having a low on-resistance is used, can perform a synchronous rectifying operation without being influenced by the inductance component. It is a synchronous rectifier circuit having a synchronous rectification element Qand a synchronous rectification control circuit ICfor turning on/off the synchronous rectification element Qin accordance with the current iflowing through the synchronous rectification element Q, including a current detection circuit for detecting the current iflowing through the synchronous rectification element Qduring an on-period of the synchronous rectification element Qas a synchronized voltage waveform, the synchronous rectification control circuit ICbeing configured so as to turn off the synchronous rectification element Qon the basis of the voltage waveform detected by the current detection circuit

Synchronous rectifier circuit

A bridge-less step-up switching power supply device includes (i) a first and a second reactor having: a first and a second main winding connected to a first and a second input terminal, respectively; and a first and a second auxiliary winding magnetically coupled to the first main winding and connected to the first and second main windings, the first and second auxiliary windings having a first and a second leakage inductance, respectively; (ii) a first and a second diode connected between the first and second auxiliary windings and a first output terminal, respectively; (iii) a first capacitor connected between the first output terminal and a second output terminal; (iv) a second capacitor connected between a connection point of a third switch and a fourth switch, and the first output terminal; and (v) a controller for controlling turning on/off of first to fourth switches.

Bridge-less step-up switching power supply device

A switching power source apparatus includes a first arm including first and second switching elements, a second arm including third and fourth switching elements, a series circuit connected between a connection point of the first and second switching elements and a connection point of the third and fourth switching elements and including a capacitor and a primary winding, a rectifying-smoothing circuit that rectifies and smoothes a voltage of a secondary winding and provides an output voltage, a reactor connected to a connection point of the first and second switching elements and a DC input end, and a controller that turns on/off the first and second switching elements alternately and the third and fourth switching elements alternately and synchronizes the first and third switching elements with each other and the second and fourth switching elements with each other.

Inverter bridge switching power source utlizing a capacitor with transformer for multiple outputs

A gate driver of a switching element Qincludes transistors Qand Qthat are totem-pole-connected to both ends of a DC power source Vcc, transistors Qand Qthat are totem-pole-connected to both ends of a DC power source Vccand have emitters connected to the gate of the switching element Q, and a transformer Thaving a primary winding and a secondary winding. The primary winding is connected to a collector of one of the transistors Qand Q, and through a capacitor, emitters of the transistors Qand Q. The second winding is connected to bases of the transistors Qand Qand the emitters of the transistors Qand Q. A maximum duty cycle of a pulse signal is determined according to a primary winding voltage of the transformer and a forward base-emitter voltage of the transistors Qand Q

Gate driver

A power factor correction circuit includes reactors Land Lto accumulate energy of an AC power source and discharge the accumulated energy, a hybrid bridge switch having two diodes Dand Dand two switching elements Qand Qto switch the energy accumulation and energy discharge of the reactors from one to another, a controllerto conduct ON-control of the two switching elements according to currents passing through the reactors and OFF-control of the two switching elements according to currents passing through the two switching elements, and a mode changerto change an operation mode of the power factor correction circuit between a discontinuous mode and a critical mode according to a voltage of the AC power source.

Growing community of inventors

Niiza, Japan

Akiteru Chiba