Light-emission drive device, light-emitting device, and light-emitting system

A light-emission drive device comprising:

• a bypass circuit configured to switch over between an inflow state, in which a drive current is made to flow into each of light-emitting elements connected in series in plurality, and a withdrawal state, in which the drive current is made not to flow but to be withdrawn;
• and
• a bypass control circuit configured to control the bypass circuit in such a way that when an externally inputted enable signal is at a first logic level, the drive current is made to flow into, or be withdrawn from, each of the light-emitting elements, and when the enable signal is at a second logic level, the drive current is made to flow into none of the light-emitting elements but to be withdrawn from all the light-emitting elements until the drive current becomes less than a specified current value.