| 摘要 |
The present invention relates to a fault detector circuit in a string of light emitting diodes comprising comparing operational amplifiers as evaluating elements, has a source of a supply voltage of a string consisting of light emitting diodes (D1) through (Dc), is dividend into three sections consisting of the diodes (D1) through (Da), further the diodes (D2) through (Db) and finally the diodes (D3) through (Dc), wherein the common point between the cathode of the last diode (Da) of the first section and the anode of the first diode (D2) of the second section is connected to the noninverting input of the first comparing operational amplifier (IC1), while the Common point between the cathode of the last diode (Db) of the second section and the anode of the first diode (D2) of the third section is connected to the noninverting input of the second operational amplifier (IC2), whereby the string consisting of the sections comprising the diodes (D1) through (Db) is connected in parallel to a divider comprising a first and a second resistors (R1) and (R2), while the string consisting of the sections comprising the diodes (D2 through Dc) is connected in parallel to a divider comprising a third and a fourth resistors (R3) and (R4), and the common point of the first and a second resistors (R1) and (R2) is connected to the inverting input of the first comparing operational amplifier (IC1) and the common point of the third and a fourth resistors (R3) and (R4), is connected to the inverting input of second operational amplifier (IC2), whereby the outputs of both the comparing operational amplifiers (IC1) and (IC2) are connected to the bases of corresponding transistors (T1) (T2), whose emitters are connected to ground and collectors are connected to the voltage source and also to an output terminal (OUT). |
