Patent ID: 7675240
Filing Date: 2010-03-09
Classification: H05B

Abstract:
1. A light emitting diode (LED) circuit having even current comprising: multiple LED strings being connected to an external power source, and each LED string comprising multiple LEDs connected in series together and having a current equalizing integrated circuit (IC) comprising a multi-transistor current mirror and having a voltage compensation module being connected between the power terminals of the LED strings and the external power source and having wherein the voltage compensation further comprises a feedback input unit being connected to the driving pins of the current equalizing IC and the external power source to obtain the feedback voltages and a feedback reference voltage; and a boosting compensation unit being connected to the external power source, the feedback input unit and the power terminals of the LED strings to obtain an input voltage, an operating voltage and the feedback reference voltage, send the voltage obtained from the external power source to the LED strings when the voltage compensation module determines all of the feedback voltages are lower than the threshold voltage value and raise and send the voltage obtaining from the external power source to the LED strings when the voltage compensation module determines any of the feedback voltages is lower than the threshold voltage value; and wherein the feedback input unit further comprises multiple diodes connected respectively to the driving pins of the current equalizing IC, and each diode having a first resistor having a second resistor having a second end being connected to the second end of the first resistor at a node.