ON Semiconductor NCP1200A Manuals

NCP1200A is a PWM current-mode controller that can achieve low standby power for universal offline power supplies. It is housed in SOIC-8 or PDIP-8 package, and can reduce optocoupler current while increasing drive capability. Due to its novel concept, the circuit can implement complete offline AC-DC adapters, battery charger or a SMPS where standby power is a key parameter. The controller operates at a fixed 40 kHz, 60 kHz or 100 kHz, and supplies itself from the high-voltage rail, avoiding the need for an auxiliary winding. This feature naturally eases the designer's task in battery charger applications. Finally, current-mode control provides an excellent audio-susceptibility and inherent pulse-by-pulse control. When the current setpoint falls below a given value, e.g. the output power demand diminishes, the IC automatically enters the so-called skip cycle mode and provides excellent efficiency at light loads. Because this occurs at a user adjustable low peak current, no acoustic noise takes place. The NCP1200A features an efficient protective circuitry which, in presence of an overcurrent 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.

NCP1200A is a PWM current-mode controller for universal off-line supplies featuring low standby power.

The NCP1200A is a PWM current-mode controller suitable for universal off-line supplies featuring low standby power. It enhances the previous NCP1200 series by offering a reduced optocoupler current together with an increased drive capability. With its novel concept, the circuit allows the implementation of complete off-line AC-DC adapters, battery chargers, or SMPS where standby power is a key parameter. The controller operates at a fixed frequency of 40 kHz, 60 kHz, or 100 kHz and draws power from the high-voltage rail, eliminating the need for an auxiliary winding. This simplifies the design task in battery charger applications. The current-mode control provides excellent audio susceptibility and inherent pulse-by-pulse control. When the current setpoint falls below a given value, the IC automatically enters the skip cycle mode, providing excellent efficiency at light loads. This occurs at a user-adjustable low peak current, ensuring no acoustic noise. The NCP1200A features efficient protective circuitry that disables the output pulses in the presence of an overcurrent condition, entering a safe burst mode to attempt a restart. The device auto-recovers once the fault has been resolved.