Abstract: The present application relates to a system-on-chip SoC, the system-on-chip SoC comprising: a power regulating input port; and a light-emitting diode LED driving circuit coupled with the power regulating input port, wherein the light-emitting diode LED driving circuit is used to provide a constant current output, and wherein the light-emitting diode LED driving circuit comprises an adjustable resistor, so that the constant current output changes with a change in resistance value of the adjustable resistor. The present application also relates to a smoke detection device.

Abstract: The present application relates to power supply technology, and in particular to a drive circuit for driving a light-emitting diode and a smoke detection device comprising the drive circuit. The drive circuit according to the present application comprises: a constant-current drive module; a light-emitting diode, a positive electrode of which is coupled with a DC power supply, the DC power supply having an output voltage greater than a maximum allowable operating voltage of the constant-current drive module; and a transistor comprising a control terminal, a first terminal coupled with a negative electrode of the light-emitting diode, and a second terminal coupled with the constant-current drive module, wherein a voltage signal having a set amplitude is applied onto the control terminal such that the transistor operates in a cut-off region when a voltage at the second terminal is close to the set amplitude.