The AL1788 is designed for primary side regulation (PSR), which removes the need for feedback optically coupled from the secondary side. This delivers efficiency of up to 91%, line and load regulation of 2% over a full range of line and load regulation, and standby power of less than 200mW.
With a PFC of >0.9, the AL1788 operates with an external MOSFET to deliver constant voltage to an LED load. This high power factor is achieved through constant on time operation, while its quasi-resonant mode valley switching method minimises switching losses for improved EMI performance.
By exploiting PSR, the complexity of the secondary side is reduced, enabling a smaller overall profile suitable for solid state lighting installations. The output voltage is regulated when operating in constant-voltage mode through feedback provided by an auxiliary winding, coupled to the secondary side winding.
The AL1788 maintains the PFC and THD performance across a wide input range over a load from 50% to 100%. It features low start-up and operating current of just 3μA and 500μA, respectively (typical), combined with ‘Burst Mode’ operation.
It includes output-open protection and output-short protection, as well as overcurrent, overvoltage and over-temperature protection. Undervoltage lockout is also integrated.
The controller-only version of AL1788 is available now and provided in the SOT26 (SC74R) package, while the MOSFET regulator options will be supplied in an SO-7 package and will be released in 2018. Both are lead, halogen, and antimony free and fully RoHS compliant.
Available in quantities of 1k units, AL1788 controllers can be purchased for $0.17 each.