LIGHTING DEVICE AND LUMINAIRE

To provide a lighting device and a luminaire that can appropriately perform dimming to a lower limit side of dimming with a simple configuration while controlling a current flowing through a light source so that the current is substantially constant.SOLUTION: A lighting device includes a constant current circuit that causes a constant DC current to flow through a light source, and can change the current value of the DC current, a detector for detecting the current value of the DC current flowing through the light source, a comparison circuit for comparing a detection value of the detector with a target value, and a controller for setting a target value of the comparison circuit based on a dimming signal, and controlling the operation of the constant current circuit based on the dimming signal and the comparison result of the comparison circuit, and when the dimming degree of the dimming signal is equal to or less than a predetermined value, the controller intermittently supplies the DC current to the light source to change a DC current supply period and a DC current supply stop period according to the dimming degree, and synchronizes the DC current supply period and the DC current supply stop period with each other to change the target value.SELECTED DRAWING: Figure 1 【課題】光源に流れる電流を実質的に一定に制御しつつ、簡単な構成で、調光下限側まで適切に調光できる点灯装置及び照明器具を提供する。【解決手段】光源に一定の直流電流が流れるようにするとともに、直流電流の電流値を可変可能な定電流回路と、光源に流れる直流電流の電流値を検出する検出部と、検出部の検出値を目標値と比較する比較回路と、調光信号に基づいて比較回路の目標値を設定するとともに、調光信号及び比較回路の比較結果に基づいて定電流回路の動作を制御する制御部と、を備え、制御部は、調光信号の調光度が所定値以下の時に、直流電流を光源に断続的に供給し、直流電流の供給の期間と直流電流の供給の停止の期間とを調光度に応じて変化させるとともに、直流電流の供給の期間と停止の期間とに同期させて目標値を変化させる点灯装置が提供される。【選択図】図１