Denso Corporation

Denso Corpora Tion

Akifumi Araragi

Yuu Yamahira

Masakiyo Sumitomo

Tetsuya Matsuoka

Kazuma Fukushima

Noriyuki Kakimoto

Masanori Yamamura

Kouichi Nishibata

A control circuit is used for a system including a power storage unit, an electric load, and a power converter electrically connected to the electric load. The control circuit includes an abnormality determination unit, an emergency power supply that generates power based on electricity supplied from the power storage unit, and a protective control unit that, when the abnormality determination unit determines that an abnormality has occurred, performs protective control for the system. The emergency power supply includes a power supply control unit configured to be operable based on electricity supplied from the power storage unit. During the period from when the voltage input to the power supply control unit starts increasing based on electricity supplied from the power storage unit, the power supply control unit starts the emergency power supply in response to the input voltage reaching a specified voltage.

Power converter control circuit

A drive circuit drives a switch that has first and second terminals and a control terminal. The drive circuit includes a discharge path, a capacitor, an AC suppressor and a DC voltage generator. The discharge path connects the control terminal and the second terminal. The capacitor has a high-potential terminal connected to the second terminal side and a low-potential terminal connected to the control terminal side. The AC suppressor has a first end connected to a part of the discharge path between the high-potential terminal the second terminal. The DC voltage generator has a connection terminal connected to a second end of the AC suppressor. The DC voltage generator regulates electric current flowing between the connection terminal and the AC suppressor so as to keep the potential of the part of the discharge path between the high-potential terminal and the second terminal higher than the potential of the low-potential terminal.

Drive circuit for switch

In a power converter, a control circuit has a speed adjustment resistor that limits a control current to adjust a switching speed of each of first and second switching elements. The speed adjustment resistor has a resistance that varies depending on a voltage at the control electrode of each of the first and second switching elements. A feedback route connects between the control electrode of the first switching element and the control electrode of the second switching element. The feedback route has a resistance that is set to be lower than a value of the resistance of the speed adjustment resistor during a predetermined Miller period of each of the first and second switching elements.

Power converter with switching elements, control circuit having speed adjustment resistor, and feedback route

In a drive circuit, a reference voltage generator generates a reference voltage that monotonically increases in a direction to pass through the threshold voltage during a voltage at the control terminal being lower than the Miller voltage. A buffer unit supplies the reference voltage output from the reference voltage generator to the control terminal of the switch, and adjusts a first transfer rate of electrical charge to or from the control terminal of the switch during at least part of a Miller period to be higher than a second transfer rate of electrical charge to or from the control terminal of the switch during the voltage at the control terminal of the switch passing through the threshold voltage. The Miller period is a period during which the voltage at the control terminal of the switch is maintained at the Miller voltage.

In an overcurrent detection circuit for switches parallely connected to each other, sense detectors are respectively provided for the switches. Each of the sense detectors detects a sense voltage of the corresponding one of the switches. The sense voltage of each of the switches is based on a sense current associated with a current flowing through the corresponding one of the switches. A parameter calculator calculates, based on the sense voltages calculated by the respective sense detectors, a determination parameter that is less subject to imbalance between currents flowing through the respective switches. A determiner determines whether a value of the determination parameter is higher than an overcurrent threshold, and determines that there is an overcurrent flowing through at least one of the switches upon determining that the value of the determination parameter is higher than the overcurrent threshold.

Overcurrent detection circuit for switches

Provided is a switch drive circuit that drives a plurality of switches mutually connected in parallel including a charge unit allowing charge current to flow to the gate of the switch; an off switch connecting between the gate of the switch and the ground; a detection unit detecting whether charge state of the gate of the switch is in a predetermined state; and a changeover unit that changes a state of off switches when the charge units allow the charge current to flow to the gate. The changeover unit changes the state of the off switches to be ON when detection units do not detect the charge state of the gate being in the predetermined state, and to change the state of the off switches to be OFF when detection units detect the charge state of the gate being in the predetermined state.

Drive circuit of switching circuit

A switching element driving device includes a main on switch that is connected to gates of a first and second IGBTs and that, when brought into a conductive state, turns on the first and second IGBTs, diodes each disposed between the main on switch and one of the gates of the first and second IGBTs, the diodes having a forward direction from the main on switch to the gates of the first and second IGBTs, an on sub-switch that is connected to the gate of the second IGBT and that, when brought into the conductive state, turns on the second IGBT, and a control circuit that controls the conductive state and a non-conductive state of the main on switch and the on sub-switch.

Switching element driving device

In a signal transmission device having a pulse generator, a RS F/F circuit and a detector, the generator generates a set pulse signal and/or a reset pulse signal when a state of a PWM signal is changed. After the generation of the set pulse signal, the generator continuously generates following pulse signals after elapse of a predetermined period of time counted from the generation of the set pulse signal. The generator adjusts, based on a selector signal, the predetermined period of time counted to a time when the following pulse signal is transmitted at a first time. The detector detects the state of the selector signal based on the predetermined period of time counted from a time when the RS F/F circuit receives the set pulse signal or the reset pulse signal to a time when receiving the following pulse signal at a first time.

Signal transmission device and drive device

In a drive circuit, a control switch is electrically connected between a negative voltage source and a reference voltage generator. A drive controller switches a discharge switch and a control switch from an off state to an on state to thereby supply a first negative output voltage to a main control terminal of a target switch. The drive controller switches the discharge switch and the control switch from the on state to the off state to thereby change the first negative output voltage to be supplied to the main control terminal of the target switch to a second negative voltage based on the reference voltage generated by the reference voltage generator. The second negative voltage is more positive than the first negative voltage.

Growing community of inventors

Kariya, Japan

Akifumi Araragi