Denso Corporation

Atsushi Kanamori

Atsushi Kobayashi

Kiyoshi Yamamoto

Sadahiro Akama

Satoshi Yoshimura

Takashi Nagasaka

Mitsuhiro Saitou

Koji Takeuchi

Noriyuki Kakimoto

Yukihiro Maeda

Hirokazu Imai

Yuji Ootani

Kan Kinouchi

Hiroyuki Yamakawa

Masatoshi Yokai

A timing adjustment method for a drive circuit, including: a rise detector for a rise start when a voltage-driven semiconductor element is turned off; a timing signal output unit outputting a speed change timing signal after a set delay time has elapsed from the rise start; and a conduction controller for a conduction control terminal of the semiconductor element using the timing signal, comprises: defining an estimated terminal voltage of the conduction control terminal when a rise completion time elapses; increasing a delay time by a predetermined unit time, and changing the drive signal to a turning off level again, when the conduction control terminal doesn't fall below the estimated terminal voltage after the drive signal is changed to a turning off level before the level is inverted; and determining a delay time, when the conduction control terminal falls below the estimated terminal voltage initially, as a set value.

Timing adjustment method for drive circuit and timing adjustment circuit for drive circuit

A drive device for controlling a power switching element to turn on and off includes: an on-side circuit performing an on operation of the power switching element; an off-side circuit performing an off operation of the power switching element; and a temperature detector detecting a temperature. At least one of the on-side and off-side circuits includes a current path for supplying or drawing a gate current of the power switching element and a switch circuit for switching the gate current. The switch circuit transitionally changes the gate current based on the temperature of the power switching element when the switching circuit switches the gate current.

Drive device

A drive device for controlling a power switching element includes: an on-side circuit that performs an on operation of the power switching element; and an off-side circuit that performs an off operation of the power switching element. The on-side circuit or the off-side circuit includes: multiple main MOS transistors; a sense MOS transistor that define a drain current of each main MOS transistor; and a sense current control circuit that controls a drain current of the sense MOS transistor to be constant; and a switch circuit that is connected to the gate of each main MOS transistor, and controls each main MOS transistor to turn on and off so as to switch a gate current in the power switching element.

A motor control apparatus has a start control section. When the motor control apparatus receives a motor start command from a host control unit when a motor is in a stop state or a low-speed rotating state where a sensorless control cannot be applied, the control section starts the motor that rotates a vehicle fan by a forced commutation which supplies a pseudo sinusoidal drive signal caused by a complementary PWM control. Thereafter, the motor control apparatus switches over to a sensorless control using a rectangular wave drive signal at an energization angle of lower than 180&#xb0;.

Motor control apparatus, vehicle fan drive apparatus, and motor control method

An energization timing determination circuit corrects a shift contained in a position signal outputted from a position detecting means and supplies energization timing appropriate to drive a motor. A correction amount computation unit computes detection intervals obtained based on position signals outputted from filters, comparators, and a position detection unit during one cycle of electrical angle. The correction amount computation unit thereby determines the duty shift length &#x3b1; and phase shift length &#x3b2; of the position signals. A control circuit corrects energization timing based on the position signals according to the detected shift lengths.

Energization timing determination circuit and determination method for energization timing of motor

A rotor position detecting circuit includes a first position detecting circuit having a low-pass filter that shapes up phase voltage induced in a phase coil and a first comparator that compares the output voltage of the low-pass filter with a threshold level to form a first rotor position signal, and a second position detecting circuit having a second comparator that compares the phase voltage with a threshold voltage and a control unit that digitally processes the output voltage of the second comparator to form a second rotor position signal. The control unit corrects the first rotor position signal by the second rotor position signal to provide a final rotor position signal when the rotation speed of the brushless DC motor is in a measurable range.

Rotor position sensing system of brushless motor

If a PWM duty instruction Ddetermined by a duty calculation circuit exceeds an upper limit value, a duty signal processing circuit in a motor drive apparatus divides a switching current supply period in each of the phases into a first current supply period and a second current supply period. In the first current supply period, the duty is set to the upper limit value. In the second current supply period, the duty is set to 100%, and the length of the second current supply period is set depending upon the duty instruction.

Motor drive apparatus and method

A protection circuit is configured to change control modes in a drive control process of a drive circuit for a motor when overvoltage is applied to a power source line while the motor is driven. With overvoltage applied, the control process is changed to a control mode to perform forced commutation control. When a predetermined time period passes after the voltage of the power source line returns to a predetermined level, the control process is changed to a sensorless control mode using a position detection circuit. This configuration can provide a motor drive apparatus capable of performing an overvoltage protection operation appropriately even when the sensorless control mode is adopted.

Motor drive apparatus and motor drive control method

A rotor position detection circuit detects a position of a rotor in a motor from a detection signal of an induced voltage generated in a stator coil. The circuit includes: a first low pass filter having a first reference potential for filtering the detection signal; a comparator for comparing an output signal from the first low pass filter with a predetermined reference voltage and for outputting a rotation position signal; and a second low pass filter having a second reference potential for filtering a virtual neutral point potential of the motor. The first reference potential is the filtered virtual neutral point potential, and the second reference potential is a ground.

Rotor position detection circuit and motor driving device

A fan motor is driven under a pulse width modulation (PWM) control. PWM signals to be supplied to a circuit for driving the fan motor are formed from carrier waves having a specified frequency and a duty ratio of the PWM control. Rotational speed of the fan motor is increased by increasing the duty ratio. In a low speed region, the fan motor is driven with a high carrier frequency to suppress driving noises of the fan motor, while it is driven with a low carrier frequency in a high speed region to reduce switching losses in semiconductor elements. The carrier frequency may be continuously decreased when the fan motor speed reaches the high speed region, or it may be stepwise decreased. The low carrier frequency used in the high speed region is set to such a frequency that guarantees a sufficient number of switching times at a maximum speed of the fan motor.

Method of driving fan motor

In a control apparatus for a motor, which rotates a fan, a semiconductor device is connected to the motor in series to drive the motor. An analog driver circuit drives the semiconductor device with an analog voltage. A PWM control circuit drives the semiconductor device with a PWM signal of a frequency of less than several tens. A switching control circuit selects the analog driver circuit and the PWM control circuit when the motor is to be rotated at speeds lower and higher than a predetermined speed, respectively.

Semiconductor device control apparatus and method

Several electronic parts are mounted on several ceramic substrates in a semiconductor device, and are wire bonded to the respective ceramic substrates through bonding wires. The electronic parts and the bonding wires are covered with an enclosing member on every ceramic substrate, and an inside of the enclosing member is filled with silicone gel for sealing. The ceramic substrates are bonded to a radiation fin together, and are mounted on a motherboard perpendicularly to the motherboard.

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Nukata-gun, Japan

Atsushi Kanamori