General description

The GreenChip is the latest generation of green Switched Mode Power Supply (SMPS)

controller ICs. The TEA1755T combines a controller for Power Factor Correction (PFC)

and a flyback controller. Its high level of integration enables cost-effective power supply

design using a very low number of external components.

The PFC operates in Quasi-Resonant (QR) or Discontinuous Conduction Mode (DCM),

with valley switching.

The specially built-in green functions provide high efficiency at all power levels. At high

power levels the flyback operates in QR mode or DCM with valley detection. At medium

power levels, the flyback controller switches to Frequency Reduction (FR) mode and limits

the peak current to an adjustable minimum value. In low power mode, the PFC switches

off to maintain high efficiency. At very low power levels, when the flyback switching

frequency drops below 25 kHz, the flyback converter switches to burst mode. During the

non-switching phase of burst mode, the internal IC supply current is minimized to further

optimize efficiency. Valley switching is used in all operating modes.

The advanced burst mode ensures high-efficiency at low power and good standby power

performance while minimizing audible transformer noise.

The TEA1755T is a Multi-Chip Module, (MCM), containing two chips. The proprietary

high-voltage BCD800 process makes direct start-up possible from the rectified universal

mains voltage in an effective and green way. The second low voltage Silicon-On-Insulator

(SOI) is used for accurate, high-speed protection functions and control.

The TEA1755T enables easy design of highly efficient and reliable supplies up to 250 W.

These power supply designs are cost-effective, requiring the minimum number of external

components.

Remark: All values in this document are typical values unless otherwise stated.

Features and benefits

Distinctive features

Integrated PFC and flyback controller

Universal mains supply operation between 70 V (AC) to 276 V (AC)

Dual-boost PFC with accurate maximum output voltage (NXP Semiconductors

patented)

High level of integration, results in cost-effective designs with very low external

component counts

Adjustable PFC switch off delay

External PFC switch on and switch off override

Accurate PFC switch on and switch off control (NXP Semiconductors patent pending)

Green features

On-chip start-up current source

Reduced IC supply current during burst mode enabling ErP lot 6

Power-down functionality for very low standby power

PFC green features

Valley/Zero-Voltage Switching (ZVS) for minimum switching losses

(NXP Semiconductors patented)

Frequency limitation reduces switching losses

PFC switched off when a low-load is detected at the flyback output

Flyback green features

Valley switching for minimum switching losses (NXP Semiconductors patented)

Frequency reduction with adjustable minimum peak current at low-power operation

maintains high-efficiency at low output power levels

Burst mode operation at very low-power levels for high-efficiency operation

Protection features

Safe restart mode for system fault conditions

Continuous mode protection using demagnetization detection for both converters

(NXP Semiconductors patented)

UnderVoltage Protection (UVP) (foldback during overload)

Accurate OverVoltage Protection (OVP) for both converters (adjustable for flyback

converter)

Mains voltage independent OverPower Protection (OPP)

Open control loop protection for both converters. The open-loop protection on the

flyback converter is safe restart

OverTemperature Protection (OTP)

Low and adjustable OverCurrent Protection (OCP) trip level for both converters

General-purpose input for latched protection, for use with system OverTemperature

Protection (OTP)