Patent ID: 6111739
Filing Date: 2000-08-29
Classification: H05B

Abstract:
A circuit for driving a plurality of light emitting diodes, comprising:a power supply for generating an output voltage between a pair of output terminals that drives a plurality of light emitting diodes; anda voltage dividing circuit electrically connected to the pair of output terminals for adjusting the output voltage, the voltage dividing circuit including:a positive temperature coefficient thermistor having a positive resistance slope characteristic wherein the resistance of the positive temperature coefficient thermistor increases as ambient temperature increases, anda negative temperature coefficient thermistor having a negative resistance slope characteristic wherein the resistance of the negative temperature coefficient thermistor decreases as ambient temperature increases;wherein the positive and negative temperature coefficient thermistors are electrically connected, and the positive and negative resistance slope characteristics are selected, to increase the output voltage between the pair of output terminals when ambient temperature of the driving circuit deviates from room temperature.