IW3627-00

The iW3627 is a high-performance single-stage AC/DC constant voltage (CV) controller with high power factor correction. It supports most commonly used isolated and non-isolated topologies including flyback, buck-boost, and buck. The device operates in constant on-time mode to achieve high power factor (>0.9) across a wide load range. It can achieve excellent output voltage regulation over line and load variation without the need for a secondary feedback circuit. It also eliminates the need for external loop compensation while maintaining stability over all operating conditions with different types of loads, including downstream DC-DC converter, constant current (CC) load, LED load, and constant resistive (CR) load. The iW3627 integrates a proprietary technique that adaptively adjusts output voltage limits to maintain overshoot and undershoot transients to less than 10% of the nominal output voltage for any load transient. The iW3627 operates in pulse-frequency-modulation (PFM) mode at light load to eliminate audible noise, and at the same time achieving less than 200mW no-load standby power consumption. The iW3627 provides maximum design flexibility by providing two multi-function pins that allow users to configure maximum and minimum switching frequencies with no cost or size impact. In addition to providing input voltage sensing for input under-voltage protection, the VIN pin also enables the active start-up scheme to achieve the shortest possible start-up time without sacrificing active efficiency.

Applications

• Smart LED lighting
• LED lighting ballast
• Front-end pre-regulator

Key features

• All-in-one low-cost off-line high power factor (PF) constant voltage (CV) controller supports flyback, buck-boost, and buck topologies in isolated or non-isolated designs
• Primary-side control achieves very tight line and load regulation (±3%)
• Enhanced MOSFET driver supports output power up to 90W or above in a tiny SOT-23 package
• User-configurable minimum switching frequency (600Hz/1kHz) ensures no-load standby power consumption <200mW or below
• Internal loop compensation ensures stable operation with different types of loads: downstream DC-DC converter, constant current (CC) load, LED load, and constant resistive (CR) load
• Supports wide range of output capacitance (with output voltage ripple ranging from 1% to 20% at full load)
• Supports universal AC input (90VAC - 277VAC) and DC input
• Adaptively adjusted output voltage limits accommodating different load conditions ensures <10% overshoot and undershoot for any load transient
• User-configurable maximum PWM switching frequency (90kHz or 120kHz)
• Built-in soft-start achieves fast and smooth start-up for all different operating conditions
• Active start-up scheme enables fastest possible startup
• Built-in single-point fault protection features: output over-load, output over-voltage, output short and input voltage under-voltage protections
• Built-in over-temperature protection
• No audible noise over entire operating range