Abstract: An inductive power transfer system for coupling a power source to a load across an air gap is provided, including a primary unit and a secondary unit separable from the primary unit and arranged to receive power inductively from the primary unit when placed proximate thereto. The system includes a multi stage comparator for monitoring operating conditions within the secondary unit and feedback loop for transmitting a feedback signal to the primary unit when predetermined operating conditions are detected within the secondary unit. The primary unit is arranged to operate in a low power mode where power is applied to the primary winding for a minimal period during each switching cycle when no feedback signal is received and a high power mode where power is applied to the primary winding for the majority of each switching cycle when a feedback signal is received.

Abstract: An inductive power transfer system for coupling a power source to a load across an air gap is provided, including a primary unit and a secondary unit separable from the primary unit and arranged to receive power inductively from the primary unit when placed proximate thereto. The system includes a multi stage comparator for monitoring operating conditions within the secondary unit and feedback loop for transmitting a feedback signal to the primary unit when predetermined operating conditions are detected within the secondary unit. The primary unit is arranged to operate in a low power mode where power is applied to the primary winding for a minimal period during each switching cycle when no feedback signal is received and a high power mode where power is applied to the primary winding for the majority of each switching cycle when a feedback signal is received.