Data transmission device
According to one embodiment, a data transmission device includes a buffer circuit configured to set a voltage level of a data signal to high or low, a power supply line for supplying a power supply voltage to the buffer circuit, a buffer control circuit configured to control a switching operation of the buffer circuit, a current circuit configured to make a dummy current flow to the power supply line, and a current control circuit configured to control the dummy current based on one of the set voltage level and a transmission timing of the data signal.
1. A data transmission device comprising:
a clock driver configured to issue a clock signal;
a buffer circuit configured to set a voltage level of a data signal to high or low, the data signal being issued according to the clock signal;
a buffer control circuit configured to control a switching operation of the buffer circuit;
a current circuit configured to make a dummy current flow from a first end of the current circuit to a second end thereof, the second end being connected to a ground line;
a power supply line connected to the first end of the current circuit and by which a power supply voltage is applied to the buffer circuit and the current circuit; and
a current control circuit configured to control the current circuit to make the dummy current flow during a time period no current is flowing in the buffer circuit, based on one of the set voltage level and a transmission timing of the data signal, wherein
the current circuit is configured to make the dummy current flow before the data signal is issued according to the clock signal.
2. The data transmission device according to claim 1 , further comprising:
a slew rate control circuit configured to control a slew rate of the dummy current.
3. The data transmission device according to claim 2 , wherein the slew rate control circuit is further configured to turn on one or more transistors with a slew rate control signal.
4. The data transmission device according to claim 3 , wherein a magnitude of the dummy current is controlled by the slew rate control signal.
5. The data transmission device according to claim 3 , wherein the one or more transistors are N-channel transistors.
6. The data transmission device according to claim 1 , wherein the dummy current is configured to reduce variation in the power supply voltage.
7. The data transmission device according to claim 1 , wherein the time period includes a time period in which the voltage level of the data signal is set to low.
8. The data transmission device according to claim 1 , wherein the current circuit is configured to make the dummy current not flow when the voltage level of the data signal is high, and make the dummy current flow when the voltage level of the data signal is low.