Description
The iW1812 is a high performance AC/DC power supply control device which uses digital control technology to build peak current mode PWM flyback power supplies. This device includes an internal power BJT and operates in quasi-resonant mode to provide high efficiency along with a number of key built-in protection features while minimizing the external component count, simplifying EMI design, and lowering the total bill of material cost. The iW1812 removes the need for secondary feedback circuitry while achieving excellent line and load regulation. It also eliminates the need for loop compensation components while maintaining stability in all operating conditions. The pulse-by-pulse waveform analysis allows for a loop response that is much faster than traditional solutions, resulting in improved dynamic load response for both one-time and repetitive load transients. The built-in power limit function enables optimized transformer design in universal off-line applications and allows for a wide input voltage range.iWatt’s innovative proprietary technology ensures that power supplies built with the iW1812 can achieve both highest average efficiency and less than 30 mW no-load power consumption in a compact form factor.
- Primary-side feedback eliminates opto-isolators and simplifies design
- Internal 800-V bipolar junction transistor (BJT)
- 64 kHz PWM switching frequency
- No-load power consumption < 30 mW at 230 VAC with typical application circuit
- Fast dynamic load response for both one-time and repetitive load transients
- Adaptive multi-mode PWM/PFM control improving efficiency
- Quasi-resonant operation for highest overall efficiency
- Ultra-low start-up current (1.7 µA typical)
- EZ-EMI ® design to easily meet global EMI standards
- Dynamic BJT base drive current control
- Very tight constant voltage and constant current regulation with primary-side-only feedback
- No external compensation components required
- Complies with EPA 2.0 energy-efficiency specifications with ample margin
- Built-in soft start
- Built-in short-circuit protection and output over-voltage protection
- Built-in current-sense-resistor short-circuit protection
- Built-in over-temperature protection (OTP)
- No audible noise over entire operating range
