PWM Current - mode Controller for Universal off-Line Supplies Featuring Standby and Short Circuit Protection With an internal structure operating at a fixed 40 kHz, 60 kHz, 100 kHz or 200 kHz switching frequency, the controller features, a high-voltage startup FET which ensures a clean and loss-less startup sequence. Its current—mode control naturally provides good audio-susceptibility and inherent pulse—by—pulse control.
When the current set point falls below a given value, e.g. the output power demand diminishes, the IC automatic ally enters the so-called skip cycle mode and provides improved efficiency at light leads while offering excellent performance in standby conditions. Because this occurs at a user adjustable low peak current, no acoustic noise takes place.
The An1203 also includes an efficient protective circuitry which in presence of an output over load condition, disables the output pulses while the device enters a safe burst mode, trying to restart. Once the default has gone, the device auto—recovers. Finally, a temperature shutdown with hysteresis helps building safe and robust power supplies.
- High-Voltage Startup Current Source
- Auto-Recovery Internal Output Short-Circuit Protection
- Extremely Low No-Load Standby Power
- Current— Mode with Adjustable Skip—Cycle Capability
- Internal Leading Edge Blanking
- 250 mA Peak Current Capability
- Internally Fixed Frequency at 40 kHz, 60 kHz, 100 kHz and 200 kHz
- Direct Optocoupler Connection
- Under voltage Lockout at 7.8 V Typical