NXP TEA1720B3T

Description

The TEA1720B3T is a small and low cost Switched Mode Power Supply (SMPS)controller IC for low power applications (up to 12.5 W) and operates directly from the rectified universal mains input. The device includes an emitter switch for driving an external low-cost bipolar power transistor. It 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 fast start-up directly from therectified 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 TEA1720B3T 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 audiblenoise and provides an energy save state which reduces the power consumption in no-load condition. The Burst mode frequency of 400 Hz enables no-load powerconsumption < 20 mW at high mains input.

A fast transient response is obtained when the TEA1720B3T is used in combination with the TEA1705 transient controller at the secondary side. The fast transient response ensures excellent control of the output voltage at load steps, at minimum no load power and at small output capacitors.

Features

• Low power SMPS controller designed for charger applications up to 12.5 W
• 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
• Cable compensation 0.3 V at maximum power
• Fast transient response when TEA1720B3T is used with the TEA1705 transient controller at the secondary side
• Integrated emitter switch to control external low-cost bipolar power transistor
• Enables no-load power consumption < 20 mW
• Very low supply current in no-load condition with energy save 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) SO8 package
• OverVoltage Protection (OVP) on Feedback control pin (FB) with auto-restart
• UnderVoltage LockOut (UVLO) and OverVoltage Protection (OVP) 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

Typical applications

• Standby supply for TV and desktop PC
• Battery chargers for smart phones and media tablets up to 12.5 W

More information

• Datasheet
• IC product information