Light-emitting diode lighting device having multiple driving stages

摘要

An LED lighting device includes a slave driving stage and a master driving stage. The slave driving stage includes a first luminescent device and a first current controller for providing a constant current setting in an ON phase. The master driving stage includes a second luminescent device and a current control unit having a second current controller and a current envelope controller. The second current controller provides a current envelope in the ON phase. The current envelope controller sets a level of the current envelope according to a rectified AC voltage. The driving current is regulated by the first current controller according to the constant current setting when the constant current setting is smaller than the level of the current envelope, or by the second current controller according to the current envelope when the level of the current envelope is smaller than the constant current setting.

主权项

1. A light-emitting diode (LED) lighting device having multiple driving stages, comprising:
a slave driving stage comprising:
a first luminescent device; anda first current controller coupled in parallel to the first luminescent device and configured to provide a constant current setting in a first phase and turn off in a second phase; a master driving stage comprising:
a second luminescent device coupled in series to the first luminescent device for providing light according to driving current; anda current control unit coupled in series to the first and second luminescent devices and including:
a second current controller configured to provide a current envelope in the first phase and turn off in the second phase; anda current envelope controller configured to set a level of the current envelope, wherein:
the driving current is regulated by the first current controller according to the constant current setting in the first phase at a specific time during a cycle of a rectified alternative-current (AC) voltage when the constant current setting is smaller than the level of the current envelope at the specific time; orthe driving current is regulated by the second current controller according to the current envelope in the first phase when the level of the current envelope at the specific time is smaller than the constant current setting.