General description

The TEA1721 is a small and low cost module Switched Mode Power Supply (SMPS)

controller IC for low power applications (up to 5 W) and operates directly from the rectified

universal mains input. The device includes a high voltage power switch (700 V) and has

been optimized for flyback converter topologies to provide high-efficiency over the entire

load range with ultra-low power consumption in the no-load condition. It provides a circuit

for start-up directly from the rectified mains voltage without any external bleeder circuits.

The converter operates as a regulated voltage source from no-load up to the maximum

output current and operates as current source that delivers the maximum current over a

broad output voltage range. Using the TEA1721, a low power converter can be built at

minimum cost and with the minimum number of external components.

The controller regulates the output voltage with primary-side sensing which eliminates the

need for an additional secondary feedback circuitry and simplifies the design. At higher

power levels, a frequency and current control mode is used. It operates with Burst mode

control at low power levels and no-load condition. The burst mode minimizes audible

noise and provides an energy saver state which reduces the power consumption in

no-load condition. The Burst mode frequency of 430 Hz enables no-load power

consumption below < 10 mW at high mains input.

Features and benefits

Power features:

 Low power SMPS controller with integrated power switch designed for applications up

to 5 W

 700 V high voltage power switch for global mains operation

 Primary sensing for control of the output voltage without optocoupler and secondary

feedback circuitry

 Minimizes audible noise in all operation modes

 USB battery charging and Energy Star 2.0 compliant

 Jitter function for reduced EMI

Green features:

 Enables no-load power consumption below < 10 mW

 Very low supply current in no-load condition with energy saver mode

 Incorporates a high voltage start-up circuit with zero current consumption under

normal switching operation

 Available in halogen-free and Restriction of Hazardous Substances (RoHS) SO7

package

Protective functions:

 OverVoltage Protection (OVP) on Feedback control (FB) pin with auto-restart

 UnderVoltage LockOut (UVLO) protection on IC supply pin

 OverTemperature Protection (OTP)

 Soft-start by reduced peak current for zero and low output voltage

 Demagnetization protection for guaranteed discontinuous conduction mode operation

 Open and short-circuit protection of the Feedback control (FB) pin

 Short-circuit protection of the charger output