LYTSwitch Family

The LYTSwitch family is a group of off-line LED drivers that deliver constant current output to drive LED loads.



The LYTSwitch-0 family is specifically designed for non-isolated non-dimming LED bulb and T8 tube applications. LYTSwitch-0 devices integrate a 700 V power MOSFET, oscillator, simple ON/OFF control scheme, a high-voltage switched current source, cycle-by-cycle current limit and thermal shutdown circuitry into a monolithic IC.

Start-up and operating power is derived directly from the voltage on the DRAIN pin, eliminating the need for a bias supply and associated circuitry.

The family delivers high efficiency (typically > 90%) and tight CC performance and enables very compact cost effective designs.

The LYTSwitch-2 family dramatically simplifies low power CC LED drivers by eliminating the optocoupler and secondary control circuitry. The family introduces a revolutionary control technique to provide very tight output current regulation, compensating for transformer and external component variations, and device parameter tolerances as well as input voltage variations.

The device incorporates a 725 V power MOSFET, a novel ON/OFF control state machine, a high-voltage switched current source for self-biasing, frequency jitter to reduce EMI, cycle-by-cycle current limit and hysteretic thermal shutdown circuitry into a monolithic IC.

The LYTSwitch-4 family enables off-line LED drivers with high power factor which easily meet international requirements for THD and harmonics. Output current is tightly regulated with better than ±5% CC tolerance1. Efficiency of up to 92% is easily achieved in typical applications.

The LYTSwitch-4 family provides excellent turn-on characteristics for leading-edge and trailing-edge TRIAC dimming applications. This results in drivers with a wide dimming range and fast start-up, even when turning-on from a low conduction angle. Large dimming ratio and low "pop-on" current.