PWM controllers enable low standby power in SMPS for notebooks, battery chargers

Addressing the growing industry need for Switched Mode Power Supplies (SMPS) manufacturers to reduce the standby power consumption at input levels higher than 75 watts (W) (medium-to-high-power), ON Semiconductor introduces the NCP1230 and NCP1231 families of PWM controllers. These current mode controllers are ideal for power supply applications in notebook adapters, off-line battery chargers and consumer electronics equipments.

The NCP1230 / NCP1231 devices allow the power supply designer to shut-down the Power Factor Correction (PFC) stage in light or no-load conditions. PFC is needed in power supply designs from 50 watt (W) to 75 W, but it typically becomes a liability by continuing to consume power at light loading. This inherently lowers the overall conversion efficiency of the power supply. The NCP1230 and NCP1231 families of PWM controllers are the only devices on the market offering the PFC shut-down feature.

“ON Semiconductor's NCP1230 and NCP1231 devices provide power supply designers with a unique tool to meet global power stand-by regulations.” said Andy Williams, ON Semiconductor director of Power Conversion Products. “These current mode controllers are compatible with any power factor correction IC and address the challenges of improving efficiency and lowering EMI in both the active and stand-by power modes.”

The NCP1230 and NCP1231 families are a series of current mode controllers offering cycle skipping at light loads, internal ramp compensation, and frequency dithering for improved electromagnetic interference (EMI) performance. Both families feature the power factor shutdown feature and are available in three frequency options ” 65 kilohertz (kHz), 100 kHz, and 133 kHz. A short-circuit protection independent of the auxiliary winding insures a safe and robust design.

The NCP1230 integrates a 2.5 milliseconds (ms) soft-start, an internal high-voltage start-up current source for lossless start-up, while in the NCP1231 the soft start is adjustable and a brown out function has been added

The NCP1230A device also includes a proprietary soft-skipping mode at light loading which prevents acoustic noise generation.

The NCP1230 and NCP1231 families are offered in both SO-8 and PDIP-8 packages (minus pin # 7) and are priced at between $0.48 and $0.53 per unit in 10,000-unit quantities.

For more information, please visit ON Semiconductor's website at

NCP1230 data sheet

NCP1231 data sheet

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