Denso Corporation

Hoshizaki Denki Kabushiki Kaisha

Takao Kuroda

Koji Yoshida

Hiroshi Imai

Katsunobu Minari

Yasuhiro Kotani

Takuya Sugie

An electronic device that has a circuit network therein and conducts at least one of power reception and communication with an external device through a wire harness includes a detection circuit and a resonance frequency shift circuit. The detection circuit detects a voltage variation caused by a noise that has a frequency component near a resonance frequency and superimposes on at least one of the wire harness and the circuit network. The resonance frequency is determined based on a characteristic impedance of the wire harness and the circuit network. The resonance frequency shift circuit shifts the resonance frequency by changing at least one of a capacitance and an inductance of the circuit network based on a level of the voltage variation detected by the detection circuit.

Electronic device

A control circuit controls a driving transistor connected in series with an electrical load between a power supply voltage and a ground. The control circuit includes a pull-up resistor connected at one end to a power supply voltage side of the driving transistor, a current detection resistor for detecting an electric current flowing from the driving transistor to the ground, a current mirror circuit including a starting transistor connected between the pull-up transistor and the current detection resistor. The current mirror circuit supplies a mirror current of the electric current. The control circuit further includes a current source circuit for supplying a driving current to a control terminal of the driving transistor in accordance with the mirror current to turn ON the driving transistor in response to an external control signal.

Driving transistor control circuit

In a transmitter device of a smart entry system for a vehicle, a transmitter antenna is provided between a variable power circuit and the ground, and is controlled by a switching circuit to transmit a searching radio wave. The transmission power of the antenna, that is, a range of reach of the searching radio wave is variably controlled by a drive output voltage applied to the antenna by a variable power circuit, which converts a battery voltage to the drive output voltage. Data to be transmitted in the searching radio wave is not used to modulate the drive output voltage but is used in an ON/OFF control of the switching circuit.

Device and method of radio wave transmission

In a disconnection detecting mode, first and second MOSFETs are turned off, a transistor is turned on, and charges of a capacitor are initialized. After that, third and fourth MOSFETs are alternately turned on/off by drive signals and having a complementary relation. When an antenna is connected normally, a pulse AC signal is transmitted to an output terminal via the antenna, and current flows from the output terminal into the capacitor via a resistor, a diode, and a resistor. When a voltage across terminals becomes equal to or higher than a determination reference voltage, a disconnection detection signal is changed to the H level (a connection state).

Disconnection detecting circuit

An ice making machine in which ice making water in a static or flowing condition is gradually frozen on the surface of an ice making plate cooled at an ice making cycle of the machine, wherein the surface of said ice making plate is made of synthetic resin or glass.

Growing community of inventors

Nagoya, Japan

Takao Kuroda