Data communication system, data communication apparatus, and sensor apparatus

A data communication apparatus that performs bidirectional communication with a slave side via a single-wire communication line, comprising:

• an input clock-side transistor connected between a reference potential and the single-wire communication line, and configured to perform switching according to an input clock;
• a first transistor connected between a first potential and the single-wire communication line;
• a second transistor having one end connected to a second potential lower than the first potential;
• a third transistor having one end connected to the second potential;
• a master-side resistor connected between another end of the second transistor and another end of the third transistor;
• and
• a master-side data reproduction circuit configured to reproduce data transmitted from the slave side via the single-wire communication line.

A data communication apparatus that performs bidirectional communication with a master side via a single-wire communication line, comprising:

• a transistor connected between the single-wire communication line and a slave-side potential equal to or higher than a master-side potential supplied to the master side;
• a clock reproduction circuit configured to reproduce a clock transmitted from the master side via the single-wire communication line;
• and
• a slave-side data reproduction circuit configured to reproduce data transmitted from the master side via the single-wire communication line,
• wherein the transistor is configured to be turned on or off by a signal that is a result of a logical operation on the reproduced clock, an enable signal of the data communication apparatus, and a data signal transmitted by the data communication apparatus to the master side, such that when an abnormality occurs in the data communication apparatus, the transistor autonomously turns on to set a potential on the single-wire communication line to a high potential level, and notifies the master-side of the abnormality.

A sensor apparatus that performs bidirectional communication with a master side via a single-wire communication line and detects a physical quantity, comprising:

• an interface circuit including a transistor connected between the single-wire communication line and a slave-side potential equal to or higher than a master-side potential supplied to the master side, a clock reproduction circuit configured to reproduce a clock transmitted from the master side via the single-wire communication line, and a slave-side data reproduction circuit configured to reproduce data transmitted from the master side via the single-wire communication line, and configured to communicate with the master side via the single-wire communication line;
• a sensor element configured to generate an electrical signal according to the detected physical quantity;
• an amplification circuit configured to amplify the electrical signal;
• an auxiliary memory configured to temporarily store input trimming data;
• a main memory configured to store, by an electric write operation, the input trimming data stored in the auxiliary memory;
• an adjustment circuit configured to adjust output characteristics of the sensor element on the basis of the input trimming data stored in the auxiliary memory, or the input trimming data stored in the main memory;
• and
• a control circuit configured to determine a control mode of the main memory, and
• the sensor apparatus having, as apparatus terminals:
• a single output terminal for outputting the electrical signal amplified by the amplification circuit to an outside;
• a single input/output interface terminal connected to the single-wire communication line for receiving trimming clocks in order to determine the input trimming data to be written to the main memory, and also inputting and outputting data;
• and a plurality of voltage application terminals for applying a voltage when writing data to the main memory.

A data communication apparatus that performs bidirectional communication with a master side via a single-wire communication line, comprising:

• a transistor connected between the single-wire communication line and a slave-side potential equal to or higher than a master-side potential supplied to the master side;
• a clock reproduction circuit configured to reproduce a clock transmitted from the master side via the single-wire communication line;
• and
• a slave-side data reproduction circuit configured to reproduce data transmitted from the master side via the single-wire communication line,
• wherein the transistor is configured to be turned on or off by a signal that is a result of a logical operation on the reproduced clock, an enable signal of the data communication apparatus, and a data signal transmitted by the data communication apparatus to the master side, such that
• the data communication apparatus transmits a high potential level to the master side when operating with a normal power supply, and outputs a GND level when not operating with the normal power supply, and
• the master side recognizes a power supply state of the data communication apparatus by determining whether or not the data communication apparatus is able to transmit the high potential level.