Automatic load detection in a dimmer

Abstract

A dimmer circuit for detecting a connected load type comprising a controller, a plurality of dimming transistors adapted to provide a dimmed hot output signal to a load, and a current sensor adapted to sense current levels of the dimmed hot output signal. The controller is adapted to store at least one load type current parameter associated with a dimming mode. The controller is further adapted to generate an asymmetric forward phase transistor drive signal with half cycles of one polarity having incrementally increasing dimming levels to drive the plurality of dimming transistors. The controller receives current levels from the current sensor and determines whether at least one of the received current levels satisfies at least one stored current parameter. When at least one current level satisfies at least one current parameter, the controller sets the dimmer to operate in a dimming mode associated with the satisfied current parameter. When the received current levels do not satisfy the stored at least one load type current parameter, the controller sets the dimmer to operate in a default dimming mode. The at least one current parameter may define one or more current events associated with a load type, such as an inrushing current event, double peaked current event, a lagging current event, or a substantially non-ratiometric current rise.