The VAS1106A is a constant current driverdesigned to be compatible with TRIAC dimmers. A string of series/parallel LEDs is tapped at the Drain of integrated high voltage switch. The LED current is programmable and kept constantby a current source.  The VAS1106A includes a bleeder circuit to ensure proper TRIAC operation by allowing current flow while the line voltage is low to enable proper firing of the dimmer. The device has an input voltage detecting circuit improves PSRR performance when AC line voltage varies.