Feedback sampling control circuit for lamp driving system

In a lamp driving system having an inverter circuit for converting a DC power to an AC power further forwarded to a lamp, and a feedback controller for adjusting said inverter circuit based on a sampling current from a feedback point, wherein said sampling current has a lamp current component and a current component of a parasitic capacitance, a feedback sampling control circuit comprising:

• a switch electrically coupled between said feedback controller and said feedback point, and controlled in response to a sampling control signal;
• a capacitive load electrically coupled between a high voltage terminal of said lamp and ground;
• and
• an effective current sampling controller electrically coupled to said capacitive load and said switch to generate said sampling control signal based on a current signal flowing through said capacitive load thereby controlling an effective current received from said sampling current by said feedback controller and minimizing said current component of said parasitic capacitance contained in said effective current.