A backlight (10), a control method for the backlight (10), and a display device. The backlight (10) comprises a plurality of light emitting modules (11) arranged in an array. Each of the light emitting modules (11) comprises a light emitting unit (111) and a control circuit (112). The control circuit (112) comprises n branches (A1-An), a controller (B), and a current module (C). Each branch of the n branches (A1-An) is connected in series with the light emitting unit (111) and the current module (C). Each branch is provided with a switch (S), and the controller (B) is separately connected to the switch (S) on each branch.