Patent ID: 8115458

Claim:
A driver comprising: a sensor configured to sense a driving current and a driving voltage for an external device comprising a capacitor; a pulse width modulator configured to supply a pulse signal to the external device; a power factor corrector comprising a phase angle estimation unit configured to estimate a phase angle variation of an input voltage to the power factor corrector based on a parameter regarding the driving current, a voltage compensator configured to compensate an error of the driving voltage, a first current estimation unit configured to estimate a variation of a charge current flowing to the capacitor based on the charge current for compensating the error by the voltage compensator and the phase angle variation estimated by the phase angle estimation unit, a second current estimation unit configured to estimate a driving current variation, and a calculator configured to calculate a duty ratio for the pulse width modulator based on the variation of the charge current estimated by the first current estimation unit and the driving current variation estimated by the second current estimation unit; and a controller configured to control the driving current for the external device and to generate the parameter based on the driving current and the driving voltage sensed by the sensor.