SIGNAL TRANSMITTER

To provide a signal transmitter with which it is possible to speed up switching between in-phase transmission and differential transmission.SOLUTION: A transmission buffer of the signal transmitter according to an embodiment includes a differential circuit unit that is connected between a first potential and a second potential, a variable current source unit that supplies a current to the differential circuit unit, a switch unit that switches states from a conductive state to a cutoff state and vice versa between a first transmission terminal and a fixed potential and between a second transmission terminal and the fixed potential, and a control unit that controls the current supplied to the differential circuit unit by the variable current source unit and controls the switch unit. A reception buffer includes a first differential pair of first conductive type that is connected between a third potential and a fourth potential, a second differential pair of second conductive type that is connected between the third potential and the fourth potential and outputs a third reception current in accordance with a first transmission signal, and outputs a fourth reception current in accordance with a second transmission signal, a first current mirror unit, and a second current mirror unit.SELECTED DRAWING: Figure 1 【課題】同相伝送と差動伝送との切り替えの高速化を図ることが可能な信号伝送装置を提供すること。【解決手段】実施形態に係る信号伝送装置の送信バッファは、第１電位と第２電位との間に接続された差動回路部と、差動回路部に電流を供給する可変電流源部と、第１送信端子と固定電位との間及び第２送信端子と固定電位との間において導通した状態と遮断した状態とを切り替えるスイッチ部と、可変電流源部が差動回路部に供給する電流を制御するとともに、スイッチ部の動作を制御する制御部と、を備え、受信バッファは、第３電位と第４電位との間に接続された第１導電型の第１差動対と、第３電位と第４電位との間に接続され、第１伝送信号に応じて第３受信電流を出力し、且つ、第２伝送信号に応じて第４受信電流を出力する、第２導電型の第２差動対と、第１カレントミラー部と、第２カレントミラー部と、を備える。【選択図】図１