Here is a block diagram of an isolated fly-back LED driver design that uses the TPS92070. Notice the arrows on the slide highlighting some of the key points. Shown in blue, the dimmer angle detection is done via the SEN, or sense pin; this is key in how the dimmer is managed. Next, labeled in green, is an arrow labeled “Non-Dissipative Dimmer Triggering”. This path is turned on at the appropriate time to allow the TRIAC trigger current to flow. Colored in red is the TRIAC Dimmer Detect trace. It is used to control the PFC circuit shown at the top of the diagram. Since dimmers have a power factor, this is disabled when a dimmer is present to improve the performance of the TPS92070. The last couple of points on the slide involve the regulation of the LED current. In isolated designs, a small transformer is used to sense the average LED current and provide regulation. The net result of this approach is a driver with very little low frequency current ripple.