Tdk Corporation

Tdk-lambda Corporation

Masahiko Hirokawa

Hiroshi Nakazawa

Tadao Senriuchi

Noriyuki Hirao

Takumi Sakamoto

Hiroshi Miyazaki

Ken Matsuura

Yasuhiro Murai

Naoyuki Ishibashi

Xiaofeng Wu

Hisanori Cho

Tomomi Yamada

A switching power supply unit includes: a transformer; an inverter circuit including first to fourth switching devices, first to third capacitors, first and second rectifying devices, a resonant inductor, and a resonant capacitor; and a driver. The first to fourth switching devices are coupled in series. The first and second capacitors are coupled in series. The first rectifying device is disposed between a first connection point between the first and second capacitors and a second connection point between the first and second switching devices. The second rectifying device is disposed between the first connection point and a third connection point between the third and fourth switching devices. The third capacitor is disposed between the second and third connection points. The resonant capacitor, the resonant inductor, and a primary winding are coupled in series between a fourth connection point between the second and third switching devices and the first connection point.

Switching power supply unit and electric power supply system

A switching power supply unit includes a pair of input terminals, a pair of output terminals, a transformer, an inverter circuit, a rectifying and smoothing circuit, and a driver. The inverter circuit includes first to fourth switching devices, a first capacitor, a resonant inductor, and a resonant capacitor. The rectifying and smoothing circuit includes a rectifying circuit including rectifying devices, and a smoothing circuit. The first to fourth switching devices are coupled in series in this order between two input terminals constituting the pair of input terminals. The first capacitor is disposed between a connection point between the first and second switching devices and a connection point between the third and fourth switching devices. The resonant inductor, the resonant capacitor, and a primary winding are coupled in series in no particular order between a connection point between the second and third switching devices and one of the two input terminals.

A number of cells can be determined before control for a battery without providing cell number setting and input means. The cell number determination device comprises voltage measuring units that select an 'i'th cell among cells that are connected in series and that configure a battery, and that measure a voltage value between a terminal in which the 'i'th cell and an (i&#x2212;1)th cell, which is in one location higher than the &#x201c;i&#x201d;th cell, are connected and a ground potential line, voltage comparators that determine an existence, nonexistence or normality of the cells by comparing a voltage value of an (i+1)th cell that is in one location lower than the &#x201c;i&#x201d;th cell with the voltage value of the &#x201c;i&#x201d;th cell measured by the voltage measuring units and a cell number determination unit that determines a number of assembled cells and normal cells and cell assembled locations in the battery.

Method for determining cell number, cell number determination device, power supply device and program

A reusable period of a battery can be maintained for a long time by recharging while avoiding abnormal heating of the battery due to over discharge. A battery protection circuit comprises a control part that cuts off a discharge switch which is a discharge path to a load for a battery when a voltage value of the battery is equal to or less than a first threshold value, or when the voltage value of the battery is less than the first threshold value, wherein the control part cuts off a power switch as a power supply path to the control part itself when the voltage value of the battery is equal to or less than a second threshold value, or when the voltage value of the battery is less than the second threshold value which is lower than the first threshold value.

Battery protection circuit, method for protecting battery, power supply device and program

A power supply control device for controlling power supply to a pair of terminals to which a load is connected, comprising a voltage measuring part for measuring a voltage which has a predetermined relationship with the voltage of the pair of terminals, a short circuit detecting part for detecting whether a short circuit exists between the pair of terminals based on the measured voltage and for making power supply to the pair of terminals stop when existence of a short circuit is detected, and a constant current supplying part for supplying a constant current though the pair of terminals; wherein the short circuit detecting part is configured to detect that the previously detected short circuit is eliminated when the voltage measured by the voltage measuring part is equal to or greater than a predetermined threshold value upon supplying the constant current through the pair of terminals.

Power supply control device, method for controlling power supply, program and power supply device

The switching power supply comprises a main circuit having a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to generate a DC output voltage, a control circuit for controlling the operation of the main circuit, and an abrupt load change detector circuit for detecting an abrupt change in the load current supplied from the main circuit, characterized in that the abrupt load change detector circuit comprises a first filter and a second filter for receiving the output voltage and detection signal generating means for generating an abrupt load change detection signal based on the outputs of the first filter and the second filter. This eliminates a power loss or operation delay caused when a resistor or a current transformer is used to directly detect the output current. Proper use of an abrupt load change detection signal allows dramatic improvement in transient response.

Switching power supply

A switching power supply suitable for driving a load whose load current may fluctuate abruptly comprises a main circuit unit including a switching circuit for converting a DC input voltage to an AC voltage and an output circuit for rectifying the AC voltage to produce a DC output voltage, and a control circuit for controlling the operation of the main circuit unit, the transfer function of the control circuit assuming a first value when the load current supplied by the main circuit unit changes at a rate not exceeding a prescribed rate and assuming a second value exceeding the first value when the load current changes at a rate exceeding the prescribed rate. The switching power supply therefore exhibits markedly improved transient response when the load current changes at a rate exceeding the prescribed rate because the transfer function of the control circuit is increased relative to that under normal condition.

Switching power supply with transfer function control circuit

A switching power supply unit capable of adjusting the inductance value of a resonance circuit and outputting a rated output voltage regardless of any fluctuation in an input voltage and a load. The switching power supply unit comprises first to fourth switching elements connected with each other in a bridge connection. A diode having a reverse polarity and a capacitor are disposed between main electrodes of each of the switching elements. A first winding of a transformer is connected between first and second connection points An inductor is inserted into a path ranging from the first connection point through the first winding to the second connection point and forms a resonance circuit in conjunction with the capacitors The inductance value L2 of the inductor is arranged to provide the output voltage Vout of an output circuit greater than or equal to the rated output voltage Vout (nom), in a minimum input voltage Vin (mm), a maximum output current Iout (max), and a switching phase-difference f of zero.

Switching power supply unit

A switching power supply comprises a transformer a switching circuit an output rectifier circuit, an output smoothing circuit, and a snubber circuit. A snubber capacitor has one terminal connected to the one terminal of a snubber diode The other end of the snubber capacitor is led to an output winding of the transformer, while the other terminal of the snubber diode is led to the other of the electrode of an output rectifier diode A snubber inductor has one end connected to the connecting point of the snubber capacitor and the snubber diode, and the other end is. connected to the input side of the output smoothing circuit. The polarity of the diode is arranged to establish a charging loop circulating through the snubber diode, the snubber capacitor and the output winding of the transformer, so as to provide a reduced loss, in a cycle in which the voltage appearing at the output winding of the transformer is the reverse direction to the output rectifier diode.

Growing community of inventors

Tokyo, Japan

Masahiko Hirokawa