Conventional LED (light emitting diode) driver designs often include switching circuits that require a timing device to control a semiconductor switch. An integrated circuit typically acts as the timing device. The integrated circuit requires its own power source and usually requires additional components for interfacing the power source to the integrated circuit. The integrated circuit may be a key component of the cost of an LED driver since the integrated circuit is itself relatively costly and the power source and the other components needed to support the integrated circuit add additional cost. As the use of LEDs in lighting applications expands, there is a need to provide LED driver designs that are low cost and that can be included in applications with limited space.
Many lighting applications require dimming. Conventional dimmers include TRIAC dimmers. One issue with using a TRIAC dimmer with an LED array is that at low current levels, the TRAIC dimmer may become unstable and may cause flicker. To address this issue a TRAIC dimmer may be connected to multiple LED arrays to provide a minimum load. However, this limits the available dimming level. In order to support low levels of dimming with an LED array, there is a need to operate a TRIAC dimmer at low current levels without requiring connection to multiple LED arrays.