ST8125 5W Flyback Controller
Specifications
Product details
Overview
The ST8125 is a high-performance current-mode PWM controller designed for cost-effective AC/DC converter applications. It provides up to 5W/4W of continuous output power over a wide input voltage range of 85-265V, with a peak output capability of 6W/5W; the optimized circuit design, combined with a cost-effective bipolar process, minimizes overall system cost. Operating in a typical flyback topology, the startup circuit uses a unique current-sinking method that utilizes the amplification of the power switch transistor, significantly reducing startup resistor dissipation; at light loads the IC automatically reduces its operating frequency for extremely low standby power. When VCC reaches 10V, over-voltage protection limits the output voltage rise to prevent damage from optocoupler or feedback-circuit failure; comprehensive overload and transformer-saturation protection plus hysteretic thermal protection are built in, and built-in line-voltage compensation keeps the maximum input power limit consistent across the full input range.
Features
- Integrated 700V high-voltage power switch
- Built-in high-voltage startup current source for fast startup
- Built-in energy-efficiency control; standby power below 0.1W
- Built-in over-voltage, under-voltage and short-circuit protection
- Built-in overload and over-temperature protection
- Precision temperature-compensated cycle-by-cycle current control
- Low startup current and low operating current
- Adaptive frequency foldback design for low EMI
- High conversion efficiency, compliant with ENERGY STAR 2.0
- Wide-input output power: 5W (A series, 6W peak); 4W (B series, 5W peak)
- Minimal external components for low system cost
- Built-in line compensation for precise LPS control
Typical Applications
- Power adapters
- Portable device chargers
- Battery chargers
- Home appliance controller power supplies
