NXP公司的TEA1751是第三代绿色开关电源(SMPS)控制器,集成了功率因子修正(PFC)和反激控制器,适用于对成本敏感和非常低外接元件的开关电源.通用输入电压从70VAC到276VAC,带精确的最大输出电压的双引导PFC. TEA1751(L)T是双芯片模块,采用高压的BCD800工艺制造,因此可直接从整流的火线电压上起动. TEA1751是适合高达250W的电源解决方案.本文介绍了TEA1751(L)T的各项特性,方框图, 典型应用框图以及有完整功能应用电路图.

GreenChip III TEA1751: integrated PFC and flyback controller

The GreenChip III is the third generation of green Switched Mode Power Supply (SMPS)
controller ICs. The TEA1751(L)T (TEA1751T and TEA1751LT) 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 off to maintain high efficiency.
During low power conditions, the flyback controller switches to frequency reduction mode
and limits the peak current to 25 % 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 TEA1751(L)T is a MultiChip Module, (MCM), containing 2 chips. The proprietary high
voltage BCD800 process which makes direct start-up possible from the rectified universal
mains voltage in an effective and green way. The second low voltage Silicon On Insulator
(SIOI) is used for accurate, high speed protection functions and control.
The TEA1751(L)T enables highly efficient and reliable supplies with power requirements
up to 250 W, to be designed easily and with a minimum number of external components.
TEA1751主要特性:
Distinctive features
Integrated PFC and flyback controller.
Universal mains supply operation (70 VAC to 276 VAC).
Dual boost PFC with accurate maximum output voltage (NXP patented).
High level of integration, resulting in a very low external component count and a
cost-effective design.
Green features
On-chip start-up current source.
PFC green features
Valley/zero voltage switching for minimum switching losses (NXP patented).
Frequency limitation to reduce switching losses.
PFC is switched off when a low load is detected at the flyback output.
Flyback green features
Valley switching for minimum switching losses (NXP 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 (NXP 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 latched on the TEA1751L and safe restart on the TEA1751.
IC overtemperature protection.
Low and adjustable OverCurrent Protection (OCP) trip level for both converters.
General purpose input for latched protection, e.g. to be used for system
OverTemperature Protection (OTP).
TEA1751应用:
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.



图1.TEA1751方框图



图2.TEA1751典型配置



图3.TEA1751典型应用框图



图4.TEA1751完整功能应用电路图



图5.PFC 准时控制框图