Fdk Corporation

Norio Fukui

Masatsuru Miyazaki

Tadashi Sato

Kenji Hamada

Miyabi Ishikawa

Tomoki Onaka

Yukio Ono

A charging device includes a rectifier circuit which rectifies AC power output by an AC power supply, a DC-DC converter which converts a voltage of DC power output by the rectifier circuit, a charging circuit which includes a positive electrode contact point in contact with a positive electrode terminal of a mounted secondary battery and a first negative electrode contact point and a second negative electrode contact point in contact with a negative electrode terminal of the secondary battery, an output voltage from the DC-DC converter being applied between the positive electrode contact point and the first negative electrode contact point, and a control circuit which includes a photocoupler that is turned on by a difference in potential between the positive electrode contact point and the second negative electrode contact point and outputs an enable signal for the DC-DC converter when the photocoupler is on.

Charging device

A charging device of the present invention includes a DC-DC converter, a charging circuit that charges a secondary battery, a power supply voltage detecting circuit that detects an input voltage Ve, an output voltage setting circuit that sets an output voltage of the DC-DC converter, and a charging control section that controls the charging circuit and the output voltage setting circuit based on the input voltage Ve, and the charging control section increases the output voltage of the DC-DC converter by a predetermined voltage in a stepwise manner while monitoring the input voltage Ve, and in a case where the input voltage Ve is decreased to a first threshold voltage Vthor less before the output voltage of the DC-DC converter increases to a rated charging voltage, the charging control section keeps the output voltage of the DC-DC converter at a voltage that is one step lower than a voltage at a time point of the case.

Charging device that can optimize charging current of a secondary battery

A charging device according to the present invention includes a rectifier circuit which rectifies AC power output by an AC power supply, a DC-DC converter which converts a voltage of DC power output by the rectifier circuit, a charging circuit which includes a positive electrode contact point in contact with a positive electrode terminal of a mounted secondary battery and a first negative electrode contact point and a second negative electrode contact point in contact with a negative electrode terminal of the secondary battery, an output voltage from the DC-DC converter being applied between the positive electrode contact point and the first negative electrode contact point, and a control circuit which includes a photocoupler that is turned on by a difference in potential between the positive electrode contact point and the second negative electrode contact point and outputs an enable signal for the DC-DC converter when the photocoupler is on.

A switching power supply includes an input terminal and an output terminal, a voltage converter including a first switching circuit configured to serve as a trigger for inputting a voltage from the input terminal and a second switching circuit configured to serve as a trigger for outputting, after the input voltage is converted, the converted voltage from the output terminal O, a control circuit configured to output a control signal for selectively sequentially driving the first switching circuit and the second switching circuit, and a delay circuit configured to delay, based on the control signal for driving any one of the first switching circuit and the second switching circuit, a subsequent driving timing of the other switching circuit that is not driven to provide a dead time when both the first switching circuit and the second switching circuit are turned off.

Switching power supply with delay for dead time adjustment

A voltage balance correction circuit includes multiple voltage correction circuits that correspond one-to-one to multiple electricity storage cells connected in series, and a control circuit that is configured to control the multiple voltage correction circuits based on voltages of the multiple electricity storage cells. The multiple voltage correction circuits include first coils that are connected to the electricity storage cells in parallel, respectively, field-effect transistors that are configured to turns on/off connections of the first coils with the electricity storage cells, respectively, under control of the control circuit, and second coils that are magnetically respectively coupled with the first coils. In the multiple voltage correction circuits, the second coils are connected in parallel.

Voltage balance correction circuit

An insulation-type switching power supply according to the present invention includes: a PWM control circuit that generates and outputs a PWM pulse and a PWM pulse respectively by alternately extracting pulses of a PWM control pulse signal at a field-effect transistor in a flyback converter circuit; a pulse transformer; a bidirectional excitation circuit that excites a primary winding of the pulse transformer in the forward direction using the PWM pulse and excites the primary winding of the pulse transformer in the reverse direction using the PWM pulse; and a switching circuit that generates a pulse signal by inverting a negative pulse of a pulse signal, induced in a secondary winding of the pulse transformer, to a positive pulse and switches the field-effect transistor by using the generated pulse signal.

Insulation-type switching power supply

A detection circuit detects a current value obtained from a mathematically processed signal to be inputted in a former half period of bisected halves of an ON period of a switching element when step-down operation is performed. Moreover, the detection circuit detects a current value obtained from a mathematically processed signal to be inputted in a latter half period of bisected halves of an ON period of a switching element when step-up operation is performed.

Current detector for bidirectional switching power supply

A switching power supply includes an insulated transformer, a full-bridge circuit which converts input DC power into AC power and outputs the AC power to a primary-side coil, an output circuit which converts AC power input from secondary-side coils into DC power and outputs the DC power, and a control circuit which controls the full-bridge circuit by using a phase shift method based on voltage output by the output circuit. When a measured value of the amount of phase shift determined from at least one of the voltage and current output by the output circuit is smaller than a theoretical value of the amount of phase shift corresponding to the switching power supply operating in a continuous current mode, the control circuit prolongs dead time used in the full-bridge circuit in accordance with the difference between the measured value and the theoretical value.

Switching power supply

A load current control apparatus according to the present invention includes a current detecting circuit adapted to detect an electric current on a power supply line used to supply electric power from a power supply unit to a load device, a field effect transistor adapted to turn on and off the power supply line, and a controller adapted to control the field effect transistor according to the electric current on the power supply line, in which the controller starts counting time from a time point when the electric current on the power supply line exceeds the overcurrent detection threshold while maintaining the field effect transistor in an ON state, sets an upper limit time corresponding to the electric current on the power supply line at that time as a time threshold based on a relationship between electric current and time set beforehand according to electrical characteristics of the field effect transistor, and turns off the field effect transistor when a time period corresponding to the time threshold elapses.

Growing community of inventors

Tokyo, Japan

Norio Fukui