| 主权项 |
1. A lighting device, comprising:
a DC power supply configured to provide a DC voltage across output ends thereof; a switching element connected in series with at least one light emitting element across the output ends of the DC power supply, the switching element including a control terminal to which a control signal is applied for adjusting a current flowing through the at least one light emitting element; and a controller configured to generate, when receiving a dimming instruction signal of setting a luminous level for the at least one light emitting element, the control signal, and apply the control signal to the control terminal of the switching element, the controller having a first mode and a second mode, the first mode being of generating a PWM signal that has a duty ratio to be changed according to the luminous level and has a constant amplitude, the second mode being of generating a PAM signal that has a constant duty ratio and has an amplitude to be changed according to the luminous level, the controller being configured to apply, as the control signal, one of the PWM signal in the first mode and the PAM signal in the second mode to the control terminal of the switching element, when the luminous level is a predetermined level or more, the controller being configured to apply, as the control signal, an other of the PWM signal in the first mode and the PAM signal in the second mode to the control terminal of the switching element, when the luminous level is less than the predetermined level. |
