FIELD: electricity.
SUBSTANCE: invention relates to lighting engineering. An excitation circuit of LED with adjustable brightness includes a resonant DC/DC converter connected to a resonant circuit. The converter includes a half-wave or double-wave switching circuit connected to the resonant circuit. An output signal of the resonant circuit is rectified and supplied to an output circuit. The output circuit can contain at least one series or shunting LED switch for switching on and off a LED unit. The control circuit controls switches of the switching circuit with a variable switching frequency and is configured to control the switching circuit for amplitude modulation of the converter and for pulse-width modulation of the converter with the first frequency of pulse-width modulation that is lower than the switching frequency. The control circuit can be additionally configured to control switching of the LED switch with the second frequency of pulse-width modulation that is lower than the switching frequency.
EFFECT: providing deep brightness adjustment with stable control of a working cycle of pulse-width modulation.
10 cl, 7 dwg
