Head unit and liquid ejection apparatus

A liquid ejection apparatus comprising:

• a first ejection unit which includes a first piezoelectric element to be driven by a first drive signal, and is configured to eject a liquid due to drive of the first piezoelectric element;
• a drive signal output circuit to which a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal are input, and which is configured to output the first drive signal;
• and
• a control circuit configured to output the ejection control signal, wherein
• the drive signal output circuit includes
• a first constant current output circuit configured to output a first constant current signal based on the first DC voltage signal,
• a second constant current output circuit configured to output a second constant current signal based on the second DC voltage signal, and
• a selection control circuit configured to control the first constant current output circuit and the second constant current output circuit based on the ejection control signal,
• the selection control circuit is configured to control whether the first constant current output circuit outputs the first constant current signal and whether the second constant current output circuit outputs the second constant current signal based on the ejection control signal, and
• the drive signal output circuit is configured to output the first drive signal corresponding to the first constant current signal and the second constant current signal.