LED lamps works follow the safety design concept of the consumer electronics, LED light source is a light emitting device of a low-voltage DC current source Can not use 100 ~ 220V AC high voltage direct lit LED desk lamp program design idea is, first of all to the high-voltage alternating current transformation A DC constant current source into a low pressure, in order to illuminate the LED light source. Use the most cost-effective way to buck and AC-DC conversion is a primary consideration of the design Today's portable electronic products using AC power AC-DC buck converter - adapter (Adapter) became not only economical, but also off-the-shelf And easy choice. The adapter's output voltage is required to be stabilized DC12V, output current to the LED light source power to choose, and generally give To 30% margin, 3 × 1W white LED light source, for example, 1W white LED standard operating current 350mA, thus three LED light source series Its circuit current is 350mA, taking into account the extended LED life and reduce the light fades, can be designed to 300mA to 330mA, did not significantly affect The brightness of the LED light, so the output current of the adapter to be elected 750mA ~ 1A.