Patent ID: 7271642

Claim:
A charge pump drive circuit for driving a light emitting diode, comprising: a charge pump for converting an input voltage source into a drive voltage to be supplied to the light emitting diode; a switch control circuit for operating the charge pump alternately between a charging phase and a discharging phase; a current regulation circuit having a current setting unit and a current regulating unit, the current setting unit being used for determining a reference current, the current regulating unit having a current regulating terminal and a feedback detecting terminal, the current regulating unit being coupled to the light emitting diode so as to control a current flowing through the light emitting diode to become proportional to the reference current, the feedback detecting terminal being used for providing a feedback signal representative of a current regulation characteristic voltage; an error amplifier for generating an error signal based on a difference between the feedback signal and a reference voltage source; and a variable resistance unit coupled between the input voltage source and the charge pump for adjusting a variable resistance in response to the error signal.