Discharge lamp driving device, projector, and discharge lamp driving method

A discharge lamp driving device comprising:

• a discharge lamp driving unit configured to supply a driving current to a discharge lamp including a first electrode and a second electrode;
• and
• a control unit configured to control the discharge lamp driving unit,
• wherein the driving current includes a first positive driving current which causes the first electrode to serve as an anode and a second negative driving current which causes the second electrode to serve as an anode,
• wherein the control unit controls the discharge lamp driving unit so that the first positive driving current and the second negative driving current are alternately supplied to the discharge lamp, a period over which the first positive driving current is supplied is changed according to a periodic first pattern, and a period over which the second negative driving current is supplied is changed according to a periodic second pattern,
• wherein the first pattern and the second pattern are patterns in which the length of the periods over which the respective driving current is supplied to the discharge lamp decreases over time within each cycle of the pattern, and
• wherein the cycle of the first pattern is phase-shifted relative to the cycle of the second pattern.