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SMPS control IC focuses on efficiency at all power levels

The GreenChip III from NXP Semiconductors is the third generation of green Switched Mode Power Supply (SMPS) controller ICs. The TEA1750 combines a controller for Power Factor Correction (PFC) and a flyback controller. Its high level of integration allows the design of a cost-effective power supply with a very low number of external components.

The special built-in green functions provide high efficiency at all power levels. This applies to quasi-resonant operation at high power levels, quasi-resonant operation with valley skipping, as well as to reduced frequency operation at lower power levels. At low power levels, the PFC switches over to burst mode control to maintain high efficiency. In burst mode, soft-start and soft-stop functions are added to eliminate audible noise.

During low power conditions, the flyback controller switches to frequency reduction mode and limits the peak current to 25 pct of its maximum value. This will ensure high efficiency at low power and good standby power performance while minimizing audible noise from the transformer.

The proprietary high voltage BCD800 process makes direct start-up possible from the rectified universal mains voltage in an effective and green way. A second low voltage Silicon On Insulator (SOI) IC is used for accurate, high speed protection functions and control.

The TEA1750 enables highly efficient and reliable supplies with power requirements up to 250 W, to be designed easily and with the minimum number of external components.

Features
* Integrated PFC and flyback controller
* Universal mains supply operation (70 V AC to 276 V AC)
* High level of integration, resulting in a very low external component count and a cost-effective design
* On-chip start-up current source

PFC features
* Valley/zero voltage switching for minimum switching losses (patented)
* Frequency limitation to reduce switching losses
* Burst mode operation if a low load is detected at the flyback output (patented)

Flyback features
* Valley switching for minimum switching losses (patented)
* Frequency reduction with fixed minimum peak current at low power operation to maintain high efficiency at low output power levels

Protection features
* Safe restart mode for system fault conditions
* Continuous mode protection by means of demagnetization detection for both converters (patented)
* Undervoltage protection (foldback during overload)
* Accurate OverVoltage Protection (OVP) for both converters (adjustable for flyback converter)
* Open control loop protection for both converters
* IC overtemperature protection
* Low and adjustable OverCurrent Protection (OCP) trip level for both converters
* Soft (re)start for both converters
* Soft stop PFC to minimize audible noise
* Mains undervoltage protection / brown-out protection
* General purpose input for latched protection, e.g. to be used for system OverTemperature Protection (OTP)

The device can be used in all applications that require an efficient and cost-effective power supply solution up to 250 W. Notebook adapters in particular can benefit from the high level of integration.

TEA1750 datasheet

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