Connecting circuit and communication interface

1 . A connecting circuit connected to a preceding stage of a transmission circuit to which a data signal is input, the connecting circuit comprising:

an initial voltage value holding circuit; and

a terminating load connected in series with the initial voltage value holding circuit,

wherein the initial voltage value holding circuit is configured to output, to the terminating load, an initial voltage value obtained when the data signal is not input, and sets both ends of the terminating load at the same potential in terms of a DC component.

2 . The connecting circuit according to claim 1 , wherein the initial voltage value holding circuit includes:

a frame detection circuit configured to detect an input of the data signal and output a frame detection signal;

a signal delay circuit configured to delay the data signal;

a sample-and-hold circuit configured to receive the data signal delayed by the signal delay circuit, detect the initial voltage value obtained when the data signal is not input, hold the initial voltage value in response to the input of the frame detection signal, and output the initial voltage value; and

a voltage maintenance circuit configured to output the initial voltage value from the sample-and-hold circuit to the terminating load.

3 . The connecting circuit according to claim 1 , wherein the terminating load includes a plurality of terminating loads.

4 . The connecting circuit according to claim 1 , wherein

the signal delay circuit is connected in parallel with the frame detection circuit.

5 . The connecting circuit according to claim 1 , wherein

the transmission circuit includes a plurality of transmission circuits to which a plurality of data signals are input,

the termination load is provided for each of the plurality of transmission circuits,

the initial voltage value holding circuit includes

an inter-channel interpolation bias detection circuit configured to detect, as the initial voltage value, a signal of a low voltage among the plurality of input data signals, and

a voltage maintenance circuit configured to receive an output of the inter-channel interpolation bias detection circuit and apply the output to the terminating load.

6 . The connecting circuit according to claim 5 , wherein the inter-channel interpolation bias detection circuit includes

a plurality of diode circuits, and

a voltage source connected to an input of the voltage maintenance circuit via a resistor,

wherein each of the plurality of data signals is input to one end of each of the plurality of diode circuits, and

wherein the other end of each of the plurality of diode circuits is connected to the input of the voltage maintenance circuit.

7 . The connecting circuit according to claim 6 , wherein when the signal of the low voltage is input to one diode circuit among the plurality of diode circuits, the inter-channel interpolation bias detection circuit is configured to output the signal of the low voltage to the voltage maintenance circuit.

8 . A communication interface comprising the connecting circuit according to claim 1 .

9 . The connecting circuit according to claim 2 , wherein the terminating load includes a plurality of terminating loads.

10 . The connecting circuit according to claim 4 , wherein the terminating load includes a plurality of terminating loads.

11 . A communication interface comprising the connecting circuit according to claim 2 .

12 . A communication interface comprising the connecting circuit according to claim 3 .

13 . A communication interface comprising the connecting circuit according to claim 4 .

14 . A communication interface comprising the connecting circuit according to claim 5 .

15 . A communication interface comprising the connecting circuit according to claim 6 .

16 . A communication interface comprising the connecting circuit according to claim 7 .