Summary of the invention
The LED desk lamp of a kind of charging of the present invention, digital dimming formula, provide a kind of digital dimming formula to carry out light modulation to LED desk lamp, the advance of its technology is: light modulation operation keys is a contact button, and the electric current by button when work is very little, guarantees the durability of button; The 2nd, dimming mode adopts the increase and decrease of LED current value to control light, and the part of working while avoiding LED light modulation is still under high voltage state works; The 3rd, by the charging of desk lamp, work separately, when charging, LED can not work, and assurance LED charging mistiming is pressed work button, and LED is burnt out.
A LED desk lamp for charging, digital dimming formula, its circuit structure is made up of charging circuit, digital type light-adjusting circuit and LED luminous plaque.
Embodiment
As shown in drawings, the left-hand component circuit of diverter switch K is desk lamp battery charger.When charging, diverter switch K plate is to the position of " 1 ", connect the line of battery E and triode T1, in the time that charger is received 220V alternating current, through capacitance-resistance voltage reduction circuit RC1 effect, 220V voltage will be arrived to some values, then send to rectification circuit device B and carry out rectification, alternating current become to the direct current of pulsation.
As shown in drawings, IC1 is three terminal regulator, and its value determines according to the value of battery E.D1 is light-emitting diode, and R2, R3 are current-limiting resistances, when charging, and in the time that battery E is not filled, triode T1 conducting, light-emitting diode D1 is bright, and pilot cell is in charging; In the time that battery is full of electricity, triode T1 cut-off, light-emitting diode D1 extinguishes, and represents that battery has been full of electricity.
As shown in drawings, the right-hand component circuit of diverter switch K is light modulation and the luminous plaque circuit of desk lamp.SC is contact button, and IC2 is that model is the counter of CD4017, and capacitor C 3 and resistance R 5 are clear circuits, and when SC does not press, IC2 does not export, and triode T2 is in cut-off state, and luminous plaque does not work; Press SC button the 1st time, IC2 is cleared and 2 ends output high level, 4, the 7 end output low levels of IC2, and triode T2 conducting, (LED) is bright for luminous plaque; Press SC button the 2nd time, the 4 end output high level of IC2, and 2,7 end output low levels, resistance R 6 on 2 ends and 4 ends, the value of R7, the value of getting R7 serious offense R6 when selected, like this, when 4 ends of IC2 are exported high level, the current value that triode T2 collector electrode is exported is bigger than original current value, and now desk lamp is brighter, realizes dimming function; While pressing SC button the 3rd time, the 7 end output high level of IC2, and 2,4 end output low levels, the high level of 7 end outputs is given pulse of clear circuit by capacitor C 4, the zero clearing of effect IC2 internal circuit, the whole output low levels of IC2 output 2,4,7, triode T2 becomes cut-off from conducting, and desk lamp extinguishes.
As shown in drawings, D2, D3, D4 are buck diodes, and D5, D6, D7 are guiding and isolation diode.