Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Mirise Technologies Corporation

Imrise Technologies Corporation

Tomohiro Nezuka

Yoshikazu Furuta

Shotaro Wada

Kunihiko Nakamura

Yasuaki Aoki

Hyoungjun Na

Shigeki Otsuka

Takasuke Ito

Yuuta Nakamura

Takashi Yoshiya

Kazutaka Honda

Akimasa Niwa

Nobuaki Matsudaira

Shogo Kawahara

Takasuke Itou

Hideji Yoshida

Soya Taniguchi

Yuu Fujimoto

Yu Fujimoto

A current sensor includes a current detection unit, a relay, a relay control unit, and a resistance value correction circuit. The current detection unit detects a detection target current based on a terminal voltage of a shunt resistor located in series with a path through which the detection target current flows and a detection resistance value for current detection corresponding to a resistance value of the shunt resistor. The relay is located in series with the path through which the detection target current flows. The relay control unit controls the relay to be turned on or off. The resistance value correction circuit calculates the resistance value of the shunt resistor as a calculated resistance value and corrects the detection resistance value based on the calculated resistance value.

Current sensor

An analog-to-digital converter includes an input-signal chopping switch, an integrator, an output chopping switch, a quantizer, and a feedback switch. The integrator is located after the input-signal chopping switch. The integrator includes an operational amplifier, an integral capacitor, and an integral-capacitor-chopping input switch being at on an input side of the integral capacitor. The output chopping switch is on an output side of the operational amplifier. The quantizer is located after the output chopping switch. The feedback chopping switch is in a feedback path from an output of the quantizer to an input of the first integrator. The input-signal chopping switch, the integral-capacitor-chopping input switch, the output chopping switch, and the feedback chopping switch execute chopping at an identical frequency. The output chopping switch sets a polarity of an input value of the quantizer to be identical before and after the chopping.

Analog-to-digital converter

A delta-sigma modulator includes a capacitively-coupled amplifier, a first integrator, a second integrator, a quantizer, a first switch, a second switch, and a control circuit. The first switch is connected between an input of the capacitively-coupled amplifier and a sampling capacitor of the capacitively-coupled amplifier to execute a chopping operation. The second switch is connected between an output of the capacitively-coupled amplifier and an input of the first integrator to execute a chopping operation. The control circuit executes modulation through the first switch at the input of the capacitively-coupled amplifier, executes demodulation through the second switch at the output of the capacitively-coupled amplifier, and imports an output signal of the capacitively-coupled amplifier into the first integrator after the demodulation.

Delta-sigma modulator

A battery monitor system includes: a reference signal generation unit; an excitation signal generation unit; a current generation unit for an excitation current; a current measurement unit for the excitation current; a voltage measurement unit for a voltage of each battery cell; an impedance measurement unit for an impedance of each battery cell; a noise measurement unit for a noise voltage; and a control unit. The control unit selects one or more battery cells not a measurement target, and the noise measurement unit measures the noise voltage near a measurement frequency equal to a frequency of an orthogonal reference signal while operating the voltage measurement unit without operating the current generation unit.

Battery monitor system

An insulated communication system includes a communication controller that sets communication data to a communication symbol through a numeral system and executes insulated communication through an insulator by adopting the communication symbol. The numeral system includes multiple states having a positive state, a negative state and a zero state. The positive state is represented by at least one positive integer, and the negative state is represented by at least one negative integer. The zero state is represented by zero being a level without generating current consumption. An absolute value of the at least one positive integer and an absolute value of the at least one negative integer are identical to each other. The communication controller sets an initial section of the communication data in the communication symbol to the positive state or the negative state, and sets a following section of the communication data to one of the multiple states.

Insulated communication system

A differential communication driver circuit includes a drive unit that drives differential signal lines connected via capacitors by a source current and a sink current. When a noise detection unit detects that in-phase noise is applied to the differential signal lines, a drive assisting unit maintains an amplitude of a differential signal output to the differential signal lines by increasing a current drive capability of the sink current.

Differential communication driver circuit

In a pulse edge detection circuit, a measurement circuit has a comparator provided therein which compares a voltage with a reference voltage and outputs a pulse signal. An RSFF puts a signal in a high level at a timing at which detecting a rise edge due to a change of the pulse signal to the high level. In such manner, a set signal of an RSFF becomes inactive and a reset signal of the RSFF becomes active, and a fall edge of the pulse signal becomes detectable. When a fall edge is generated due to a change of the pulse signal from the high level to the low level, the set signal of the RSFF becomes active, and a signal becomes high level.

Pulse edge detection circuit

An analog-to-digital converter includes a primary converter and a secondary converter. The primary converter executes conversion processing to convert an analog input signal to a first digital signal through delta-sigma modulation. The secondary converter outputs a second digital signal by converting amplified analog output of a quantization error in the primary converter to the second digital signal.

A differential transmission circuit for a communication device performs bidirectional communication via a differential transmission line. The differential transmission circuit include: output transistors that are turned on and off according to a drive signal during a transmission period; a signal generation unit that generates and outputs the drive signal; short-circuit transistors connected between gates and drains of the output transistors; and a cut off unit that cuts off a supply path of the drive signal between the signal generation unit and the gates of the output transistors. The cut off unit cuts off the supply path of the drive signal during a reception period in which a reception operation is performed by the communication device.

Differential transmission circuit

A signal detection circuit detects, as a detection target signal, a signal of a main terminal of a switching element by comparing the detection target signal with a reference signal. The signal detection circuit includes: a signal generation unit generating the reference signal; a first capacitor having a first terminal connected with the main terminal of the switching element; a second capacitor having a first terminal connected with an output terminal of the signal generation unit; and a detection circuit receiving, as input signals, a signal output from a second terminal of the first capacitor and a signal output from a second terminal of the second capacitor, and the detection circuit detecting the detection target signal based on the input signals.

Signal detection circuit

A current sensor for a detection target current using a shunt resistor includes: a resistance value correction circuit having a correction resistor; a signal application unit that applies an alternating current signal to a series circuit of the shunt resistor and the correction resistor; a voltage detection unit that detects terminal voltages of the shunt resistor and the correction resistor; and a correction unit that calculates a resistance value of the shunt resistor and corrects the resistance value for detection; and a power supply circuit having a first power supply generation unit that generates a first power supply of the signal application unit from an input power supply of an outside; and a second power supply generation unit that generates a second power supply of the voltage detection unit.

In a communication system, a control unit and driver units are connected in a daisy chain; each unit includes a corresponding insulated communication circuit, respectively. The control unit measures a communication delay time between the control unit and each driver unit from a response time to transmission of a pulse signal performed to each driver unit during a measurement period. Then, based on each communication delay time, the control unit transmits a shift time to each driver unit for equalizing the timing of signals output by the driver units. When each driver unit receives, from the control unit, an instruction instructing each driver unit to output a signal, each driver unit outputs the signal when the shift time has elapsed.

Communication system

A clock signal generation circuit for a switched capacitor circuit with a chopping function unit includes: first and second synchronous clock circuits that generate first and second synchronous clock signals, respectively; an edge signal generation circuit that generates one or more rise and fall edge signals by delaying the first synchronous clock signal; a first clock generator that generate a first clock signal group for driving the switched capacitor circuit; and a second clock generator that generates a second clock signal group for driving the chopping function unit. Frequencies of the first and second clock signal groups are respectively defined by the first and second synchronous clock circuits. Rise and fall edges of the first and second clock signal groups are defined by the edge signal generation circuit.

Clock signal generation circuit

A current sensor for detecting a current based on a terminal voltage and a resistance value of a shunt resistor, includes: a resistance value correction circuit having: correction resistors; a signal application unit; a voltage detection unit that detects terminal voltages of the shunt resistor and a part of the correction resistors in a first period, and terminal voltages of all of the correction resistors in a second period; and a correction unit that corrects the resistance value for current detection based on a calculated resistance value of the shunt resistor. Resistance values and resistance accuracies of the correction resistors are higher as the plurality of correction resistors are disposed farther from the shunt resistor.

A differential communication circuit is connected to a communication line formed of a positive communication line and a negative communication line for differential communication. The differential communication circuit includes: a series circuit that includes a resistor element and a connection switch. The resistor element is connected between the positive and negative communication lines when the connection switch is turned on. The circuit also includes a transmission unit that is configured to output a differential signal to the communication line and a controller that is configured to change impedance of the communication line by turning on the connection switch in a period during which the transmission unit does not output the differential signal.

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Kariya, Japan

Tomohiro Nezuka