Denso Corporation

Junichi Nagata

Hiroyuki Ban

Junji Hayakawa

Akio Kojima

Masahiro Kitagawa

Tsuneo Maebara

Kiyoshi Yamamoto

Hirokazu Itakura

Toru Itabashi

Yusuke Shindo

Akito Itou

Junichi Fukuta

Ryotaro Miura

Satoshi Shiraki

Yutaka Fukuda

Yoshiyuki Hamanaka

Tomohisa Yamamoto

Takeshi Ishikawa

Takeshi Miki

Tomoyuki Muraho

Takanori Ishikawa

Shinichi Maeda

Masayuki Kominami

Hiroyuki Kawabata

Atsuo Onozaki

A drive circuit supplies a charging current via a charging path to drive the control terminal of a voltage-controlled switching device, with a resistor and a switching device being connected in series in the charging path. A control circuit in an integrated circuit of the drive circuit operates an internal switching device such as to selectively enable/interrupt the charging current and to regulate the voltage drop across the resistor to a fixed value. The switching device connected in the charging path can be readily changed from the internal switching device to an external switching device, in accordance with the operating requirements of the driven switching device.

Integrated circuit-based drive circuit for driving voltage-controlled switching device and method of manufacturing the drive circuit

A drive device has a break circuit. The break circuit inputs phase-current values transferred from phase-current sensors mounted on an electrical path of a motor generator. A power switching element is equipped with a freewheel diode connected in parallel with each other. An inverter has pairs of the power switching elements. In each pair, the power switching element in a high voltage side and the power switching element in a low voltage side are connected in series. It is detected for the freewheel diode to be in a freewheel mode when a forward current flows in the freewheel diode. The break circuit detects the freewheel mode where the current flows in the freewheel diode in a lower arm when the phase-current value is not less than a predetermined threshold value. The break circuit detects the freewheel mode where the current flows in the freewheel diode in an upper arm when the phase-current value is not more than the threshold current value.

Drive device for electric power conversion circuit

A drive unit controls the operation of a corresponding power switching element such as IGBT which forms an inverter and a converter. The drive unit controls the operation of the corresponding power switching element to supply an operation current to a motor generator. First and second switching elements in the drive unit are simultaneously turned on when an operation signal transferred from a control device is switched to a turning-on instruction operation signal. The voltage at the gate terminal of the power switching element is shifted to a divided voltage obtained by dividing a voltage of the power source by first and second resistances connected in series in the drive unit. When a mirror time period of the power switching element is elapsed, the second switching element only is turned off in order to shift the gate voltage of the power switching element to the voltage of the power source.

Device for driving switching elements

A level shift circuit includes a first capacitor circuit including capacitors connected in series between a ground and a predetermined potential, a first trigger circuit coupled to the predetermined potential side of the first capacitor circuit, an input terminal coupled to the ground side of the first capacitor circuit, a second capacitor circuit including capacitors connected in series between the ground and the predetermined potential, a second trigger circuit coupled to the predetermined potential side of the second capacitor circuit, an inverter coupled between the input terminal and the ground potential side of the second capacitor circuit, and a SR latch circuit having a first input coupled to an output of the first trigger circuit and a second input coupled to an output of the second trigger circuit.

Level shift circuit

An overcurrent detection circuit for detecting an overcurrent condition in an output transistor connected in series with an electrical load includes a pair of transistors having input terminals connected together. The pair of transistors is interposed between a current mirror circuit and a resistor and between the current mirror circuit and a detection transistor capable of being turned on at the same time as the output transistor. When a voltage is applied to the input terminals of the pair of the transistors, output terminals of the current mirror circuit are fixed at the same potential. Thus, even when an early effect occurs in the current mirror circuit, an electric current flowing through the resistor becomes equal to that flowing through the detection transistor. The overcurrent detection circuit can accurately detect the overcurrent condition based on a voltage drop across the resistor.

Overcurrent detection circuit

A series-regulator type of power supply circuit is provided. In the circuit, the emitter and collector of a transistor are connected to power input/output terminals. A control circuit controls a base current of the transistor based on the output voltage detected at the power output terminal and a given target voltage. A resistor circuit connects the base and the collector of the transistor. A bypass circuit connects the emitter and the base of the transistor and passes a bypass current. The accepting circuit connected to the power output terminal accepts (absorbs) current from an output current. An amount of the acceptance current is equal to or larger than an amount of the bypass current and a product of the bypass current and a resistance value of the resistance circuit is equal to or more than a difference between a voltage at the power input terminal and the target voltage.

Power supply circuit with series regulator

In a band gap reference voltage circuit, a band gap cell circuit composed of two transistors is driven with different current densities under a bias condition in which first and second reference voltages output in accordance with the operating states of the two transistors are equal to each other, thereby outputting a band gap reference voltage from a reference voltage output line. A differential amplifying circuit that is supplied with the first and second reference voltages as differential input signals subjects the differential input signals thus supplied to differential amplification. A level shift circuit is connected between a power supply line and the reference voltage output line and supplied with an output voltage of the differential amplifying circuit to carry out a level shift operation on the output voltage concerned.

Band gap reference voltage circuit

A drive circuit that supplies electric power to an electric load from a DC electric source includes a pair of series-connected first and second MOSFETS of the same conduction type, a pair of clamp circuits respectively connected between the drains and gates of the first and second MOSFETS, a series circuit of a first resistor and a switch, a first test terminal; a second test terminal connected to a joint of the first and second MOSFETS, a third test terminal for operating the switch, a fourth test terminal connected a joint of the first resistor and the switch; and a second resistor connected between the gate of the second MOSFET and the first test terminal. The switch and the first resistor are connected between the gate and the source of the first MOSFET to close when the drive circuit is normally operated and to open when it is given a high voltage test.

Drive circuit and method of applying high voltage test thereon

A constant voltage supplying circuit including an output transistor is connected to a power source line and an output terminal. A base-emitter voltage of the output transistor is detected by a voltage detecting circuit composed of a transistor. A current-outputting circuit for supplying a current determined based on the voltage detected by the voltage detector to a reference voltage supplying circuit is used in the constant voltage supplying circuit. The reference voltage is supplied to a base of the output transistor to cancel a base-emitter voltage of the output transistor and to equalize the output voltage to a voltage generated in a reference voltage generating element included in the reference voltage supplying circuit. In this manner, the output voltage is kept constant notwithstanding variation of output current.

Circuit for supplying constant voltage

The power supply PS includes a voltage detecting circuit VD for detecting a voltage level Vs inputted from an external voltage source, a boot strap circuit BS, andET connected in parallel with BS, a smoothing circuit SM connected with the BS output terminal and a regulating IC connected with BS and FET. The regulating IC includes VD, a transistor Tr and condenser C. Both when a PS switch is turned on and when VD detects that Vs (which once descended) reaches an ascending reference, a high level driving signal generated by VD is changed into a low level signal, thereby turning off Tr connected with C. Thus, until Tr completes charging up C, a duty ratio of a pulse width modulation (PWM) signal dependent on the SM output is made gradually greater, thereby surely preventing a rush current by turning on and off the FET by the PWM signal.

Switching regulator and power supply using the same

A load driving circuit controls a feed of a power supply voltage of a power supply to a load. A power MOSFET is connected in series with the power supply and the load. A load driving state such as disconnection and short circuit of the load is detected by comparing a predetermined reference voltage and a voltage of the load and MOSFET node. For this, a pull-up resistor is connected between the power supply and the load. A diode is connected between source and gate of the MOSFET. A transistor circuit is connected between source and gate of the MOSFET to discharge a gate capacitance of the MOSFET. In a non-feed mode, a driving current is made to flow in a control electrode of the transistor circuit. The magnitude of the driving current is preferably enough to operate the transistor circuit and the voltage drop caused by the driving current is preferably smaller than a difference between the power supply voltage and the predetermined reference voltage.

Load driving circuit capable of raised accuracy detection of disconnection and short circuit of the load

An integrated circuit device includes an output terminal for connection with a terminal of an external load, and first and second power supply terminals for connection with a terminal of an external power supply. A switching element is connected between the output terminal and the first power supply terminal. The switching element, the external load, and the external power supply form a load current flow path. An impedance circuit is connected between the output terminal and the second power supply terminal. An abnormality detection circuit operates for monitoring a voltage at the output terminal, and detecting an abnormal condition on the basis of the monitored voltage. A drive control circuit operates for driving and controlling the switching element.

Integrate circuit device

A series circuit including a capacitor and a resistor for detecting variation of the output voltage of dc power supply is further provided. During startup, a charge current corresponding to the rising rate of the output voltage flows through the series circuit. This reduces the base current of the power transistor to suppress the rising rate to suppress overshoot and undershoot. A clamp circuit is provided to the differential amplifier for detecting the error voltage. This prevents the saturation in the differential amplifier or limit the voltage variation amplitude to accelerate the operation of the operational amplifier and suppress undershoot. A delay circuit for disabling to driving circuit for the power transistor for the initial interval may be further provided to suppress the initial rapid rise of the output voltage.

DC power supply with output voltage detection and control

The present invention discloses an output circuit, by which it is possible to reduce power consumption while maintaining maximum voltage value to be outputted at high level. In this output circuit, a charge-and-discharge circuit uses a terminal voltage Vc of a capacitor as a trapezoidal wave voltage, and a drive circuit drives an output transistor based on the terminal voltage Vc, and a voltage Vo equal to the terminal voltage Vc is outputted to the load. A voltage detection circuit detects an emitter voltage (Vc&plus;VF) of the transistor and generates an electric current proportional to the terminal voltage Vc. This electric current is turned to a base current of the output transistor via a variable current circuit. Therefore, a base current proportional to the output voltage Vo is supplied to the output transistor.

Output circuit

A constant voltage circuit robust to the input voltage lowering is disclosed. The invention is applied to a constant voltage circuit fed with an input voltage through first and second power conductors for transferring the input voltage to a load as an output voltage through an output transistor. An inventive constant voltage circuit is provided with a substitute circuit, responsive to a detection of the lowing of the input voltage to a predetermined voltage, for providing a substitute output path that is connected in parallel with the output transistor. Doing this minimize the degree of lowering of the second voltage due to the lowering of said first voltage. The output transistor may be nay of NPN and PNP transistors and P-type and N-type MOS FETs.

Growing community of inventors

Okazaki, Japan

Junichi Nagata