DIMMING CONTROLLING CIRCUIT FOR LED

摘要

A dimming controlling circuit for LED comprises: a switch (S0) configured to connect a main circuit (50) and a power grid; a switch-on duration controlling circuit (10) configured to output a switch-on duration controlling signals according to action times of the switch (S0); a switch-off controlling circuit (20) configured to output a switch-off controlling signal according to a comparison result of the voltages of the switch-on duration controlling signal and of a signal from a terminal of a switch transistor (M1) in the main circuit (50); a switch-on controlling circuit (30) configured to generate a switch-on controlling signal after a first preset duration since receiving the switch-off controlling signal; and a logic unit (40) configured to output a switch transistor controlling signal. The dimming controlling circuit for LED of the present disclosure is simple in structure and a manufacturing cost is low.