Driver circuit, transmitter, and communication system

A driver circuit, comprising:

• a first driver provided between a first power supply of a first voltage and a ground power supply, the first driver receiving a first input signal and outputting a signal responsive to the first input signal;
• a regulator connected to a second power supply of a second voltage lower than the first voltage, the regulator providing a third power supply of a third voltage lower than the second voltage;
• a second driver provided between the third power supply and the ground power supply, the second driver receiving a second input signal and outputting a signal responsive to the second input signal;
• an output terminal connected in common to the output of the first driver and the output of the second driver;
• and
• an anti-load fluctuation circuit for preventing or reducing fluctuations in the third voltage of the third power supply at a time of transition from a first mode in which the first driver operates to a second mode in which the second driver operates,
• wherein
• the anti-load fluctuation circuit includes a current route provided between the third power supply and the ground power supply, the current route being switched between a conductive state and a non-conductive state in response to a given signal, and
• in the case of transition from the first mode to the second mode, the anti-load fluctuation circuit is configured to give a signal to the current route so as to bring the current route to the conductive state while the mode is in the first mode and, at the time of transition to the second mode, bring the current route to the cut-off state.