Patent ID: 8482210

Claim:
A luminance adjusting circuit, comprising: an integrated circuit configured for converting alternating current provided by a power supply into direct current; an LED (light emitting diode) module comprising a plurality of LEDs; a button module configured for creating trigger signals in response to user's operation on the button module; a switch module connected to the LED module; a processing unit comprising: a storage module configured for storing a table defining a relationship between luminance levels of the LED module and average current flowing through the LED module; a judging and executing module configured for determine a desired luminance level according to the trigger signals, and further determines the average value of the current in the table corresponding to the desired luminance level; and a signal generating module connected to the switch module, and configured for producing a timing signal according to the average value of the current required controlled by the judging and executing module, to turn on or off the switch module periodically for adjusting a current flowing through the LED module to obtain an average current value which according to the table equates to the desired luminance level, thereby adjusting the luminance level of the LED module to the desired the luminance level.