J4 ›› 2009, Vol. 36 ›› Issue (3): 433-437.

• Original Articles • Previous Articles     Next Articles

Design research on the high-precision programming constant current driver of the white light LED

LI Xian-rui1;LAI Xin-quan1;WANG Song-lin2;LI Yu-shan1
  

  1. (1. Research Inst. of Circuit Design, Xidian Univ., Xi'an  710071, China;
    2. School of Mechano-electronic Engineering, Xidian Univ., Xi'an  710071, China)
  • Received:2008-07-03 Revised:2008-08-20 Online:2009-06-20 Published:2009-07-04
  • Contact: LI Xian-rui E-mail:lixr@xidian.edu.cn

Abstract:

An accurate programmable constant current driver for the white light LED is designed. An autozero amplifier, based on the autozero technique, is constructed in the chip. The current delivered to the LED load is controlled by the external resistor and the enable pins. Three discrete constant current settings are available and may be selected at the supply voltage from 2.9 V to 4.4 V, which is up to 1 A. Measurement results show that the variation in the ratio of the external resistor current to the LED load current is less than 2.3%, when the LED load current changes from 200 mA to 800 mA. The driving current of 800 mA varies by less than 0.46% when the supply voltage changes by ±10%.

Key words: amplifier, light emitting diode, constant-current driving, autozeroing

CLC Number: 

  • TN432