Abstract: An air-fuel ratio sensor control apparatus comprises a voltage control part configured to control a voltage Vo1 applied to a cell of an air-fuel ratio sensor in accordance with a sensor current flowing in the cell and a current detection part configured to detect the sensor current as a physical value, which indicates the air-fuel ratio. In the air-fuel ratio sensor control apparatus, a voltage varying time point, at which the voltage control part varies the voltage Vo1, and a current detecting time point, at which the current detection part detects the current, are shifted from each other. A time period Ta from the current detecting time point, which is immediately before the voltage varying time point, to the voltage varying time point and a time period Tb from the voltage varying time point to the current detecting time period, which is immediately after the voltage varying time point, are set to satisfy Ta<Tb.

Abstract: A controller of an air-fuel ratio sensor includes, in a digital processor, an adjuster and a control unit, among which the adjuster adjusts a second input digital value for a control of an output voltage of a second voltage application circuit to a preset voltage, and the control unit controls, based on a calculation result of a digital value of a sensor current, a first input digital value for a control of an output voltage of an output terminal of a first OP amplifier of a first voltage application circuit to a voltage Vu based on the equation, Vu=Vout±(Vtar+Is×Rs), so that an application voltage applied to the air-fuel ratio sensor is quickly adjusted to a target voltage.

Abstract: A power supply device comprises: a first linear regulator, which receives a voltage from a direct-current power supply at all times and outputs a first voltage; a step-down switching regulator, which receives the voltage from the direct-current power supply through a path via a power supply switch and outputs an intermediate voltage, and a second linear regulator, which receives the intermediate voltage and outputs a second voltage. The power supply device outputs a higher one of the first voltage and the second voltage. The first linear regulator has a smaller current consumption and a higher minimum operating voltage than the second linear regulator. When the voltage supplied from the direct-current power supply is lower than or equal to a predetermined threshold value, the switching regulator drives a main switching component interposed in series with a voltage input-output path to turn on at all times.

Abstract: A power supply device comprises: a first linear regulator, which receives a voltage from a direct-current power supply at all times and outputs a first voltage; a step-down switching regulator, which receives the voltage from the direct-current power supply through a path via a power supply switch and outputs an intermediate voltage, and a second linear regulator, which receives the intermediate voltage and outputs a second voltage. The power supply device outputs a higher one of the first voltage and the second voltage. The first linear regulator has a smaller current consumption and a higher minimum operating voltage than the second linear regulator. When the voltage supplied from the direct-current power supply is lower than or equal to a predetermined threshold value, the switching regulator drives a main switching component interposed in series with a voltage input-output path to turn on at all times.

Abstract: An air-fuel ratio sensor control apparatus comprises a voltage control part configured to control a voltage Vo1 applied to a cell of an air-fuel ratio sensor in accordance with a sensor current flowing in the cell and a current detection part configured to detect the sensor current as a physical value, which indicates the air-fuel ratio. In the air-fuel ratio sensor control apparatus, a voltage varying time point, at which the voltage control part varies the voltage Vo1, and a current detecting time point, at which the current detection part detects the current, are shifted from each other. A time period Ta from the current detecting time point, which is immediately before the voltage varying time point, to the voltage varying time point and a time period Tb from the voltage varying time point to the current detecting time period, which is immediately after the voltage varying time point, are set to satisfy Ta<Tb.

Abstract: In an impedance detector, a current application portion applies a first current and a second current, directions of which are opposite to each other, to an element of an oxygen concentration sensor. A detection portion detects a difference between a current application prior voltage and a current application subsequent voltage. The current application prior voltage is a voltage between both of ends of the element before being applied with the first current, and the current application subsequent voltage is a voltage between both of the ends of the element when being applied with the first current. An impedance calculation portion calculates an impedance of the element based on the difference detected by the detection portion and a value of the first current. The current application portion is configured to change a current application time to apply the first current and the second current according to a command provided thereto.

Abstract: An air-fuel ratio sensor control device, connected with two-cell type air-fuel ratio sensor having electromotive force and oxygen pump cells with first to third two-cell terminals or a one-cell type air-fuel ratio sensor having a single cell with first and second one-cell terminals, includes: first to third connection terminals for connecting the one-cell or two-cell type air-fuel ratio sensor; a control circuit that is switchable between a two-cell circuit configuration for controlling the two-cell type air-fuel ratio sensor through the first to third connection terminals and a one-cell circuit configuration for controlling the one-cell type air-fuel ratio sensor through the first and second connection terminals; and a control unit that sets a circuit configuration of the control circuit to the one-cell or two-cell circuit configuration.

Abstract: A controller of an air-fuel ratio sensor includes, in a digital processor, an adjuster and a control unit, among which the adjuster adjusts a second input digital value for a control of an output voltage of a second voltage application circuit to a preset voltage, and the control unit controls, based on a calculation result of a digital value of a sensor current, a first input digital value for a control of an output voltage of an output terminal of a first OP amplifier of a first voltage application circuit to a voltage Vu based on the equation, Vu=Vout±(Vtar+Is×Rs), so that an application voltage applied to the air-fuel ratio sensor is quickly adjusted to a target voltage.

Abstract: An impedance detector includes a current application portion, a detection portion, a calculation portion and a changing portion. The current application portion applies an impedance detection current for detecting an impedance of an element of an oxygen sensor to the element. The detection portion detects a difference between a current application prior voltage and a current application subsequent voltage of the element. The calculation portion calculates the impedance of the element based on the difference detected by the detection portion and a value of the impedance detection current applied by the current application portion. The current application portion can change the value of the impedance detection current applied to the element. The changing portion determines to change the value of the impedance detection current according to the difference detected by the detection portion.

Abstract: An air-fuel ratio detection device includes a resistor, a first voltage application section, a second voltage application section, an amplification section, an A/D conversion section, and an arithmetic section. The first voltage application section applies a direct current voltage to a first end of a series circuit constituted of an air-fuel ratio sensor and the resistor. The amplification section amplifies a voltage across the resistor and outputs an amplified voltage as an output voltage. The A/D conversion section carries out an A/D conversion of the output voltage every time before the second voltage application section switches a voltage applied to a second end of the series circuit between a first voltage and a second voltage. The arithmetic section calculates a sensor current and an impedance of the air-fuel ratio sensor using two consecutive A/D conversion results by the A/D conversion section.

Abstract: An air-fuel ratio sensor control device, connected with two-cell type air-fuel ratio sensor having electromotive force and oxygen pump cells with first to third two-cell terminals or a one-cell type air-fuel ratio sensor having a single cell with first and second one-cell terminals, includes: first to third connection terminals for connecting the one-cell or two-cell type air-fuel ratio sensor; a control circuit that is switchable between a two-cell circuit configuration for controlling the two-cell type air-fuel ratio sensor through the first to third connection terminals and a one-cell circuit configuration for controlling the one-cell type air-fuel ratio sensor through the first and second connection terminals; and a control unit that sets a circuit configuration of the control circuit to the one-cell or two-cell circuit configuration.

Abstract: In an impedance detector, a current application portion applies a first current and a second current, directions of which are opposite to each other, to an element of an oxygen concentration sensor. A detection portion detects a difference between a current application prior voltage and a current application subsequent voltage. The current application prior voltage is a voltage between both of ends of the element before being applied with the first current, and the current application subsequent voltage is a voltage between both of the ends of the element when being applied with the first current. An impedance calculation portion calculates an impedance of the element based on the difference detected by the detection portion and a value of the first current. The current application portion is configured to change a current application time to apply the first current and the second current according to a command provided thereto.

Abstract: An impedance detector includes a current application portion, a detection portion, a calculation portion and a changing portion. The current application portion applies an impedance detection current for detecting an impedance of an element of an oxygen sensor to the element. The detection portion detects a difference between a current application prior voltage and a current application subsequent voltage of the element. The calculation portion calculates the impedance of the element based on the difference detected by the detection portion and a value of the impedance detection current applied by the current application portion. The current application portion can change the value of the impedance detection current applied to the element. The changing portion determines to change the value of the impedance detection current according to the difference detected by the detection portion.

Abstract: An air-fuel ratio detection device includes a resistor, a first voltage application section, a second voltage application section, an amplification section, an A/D conversion section, and an arithmetic section. The first voltage application section applies a direct current voltage to a first end of a series circuit constituted of an air-fuel ratio sensor and the resistor. The amplification section amplifies a voltage across the resistor and outputs an amplified voltage as an output voltage. The A/D conversion section carries out an A/D conversion of the output voltage every time before the second voltage application section switches a voltage applied to a second end of the series circuit between a first voltage and a second voltage. The arithmetic section calculates a sensor current and an impedance of the air-fuel ratio sensor using two consecutive A/D conversion results by the A/D conversion section.

Abstract: A positive displacement liquid-delivery apparatus includes a positive displacement pump 110 and a differential pressure control unit 142. The positive displacement pump 110 includes a liquid-delivery chamber 128 having a watertight housing 122 with one part formed of a flexible diaphragm 124, and a diaphragm driver 136 linked to the diaphragm 124 for deforming the same to discharge fluid from the liquid-delivery chamber 128. The differential pressure control unit 142 uniformly controls the differential pressure inside and outside the diaphragm 124 during the pumping process.