General description

The TEA1733LT/N1 is a low cost Switched Mode Power Supply (SMPS) controller ICs

intended for flyback topologies. They operate in fixed frequency mode. To reduce

ElectroMagnetic Interference (EMI), frequency jitter has been implemented. Slope

compensation is integrated for Continuous Conduction Mode (CCM) operation.

The TEA1733LT/N1 includes OverPower Protection (OPP). This enables the controller to

operate under overpower situations for a limited amount of time.

Two pins, VINSENSE and PROTECT, are reserved for protection purposes. Input

UnderVoltage Protection (UVP) and OverVoltage Protection (OVP), output OVP and

OverTemperature Protection (OTP) can be implemented using a minimal number of

external components.

At low power levels the primary peak current is set to 25 of the maximum peak current

and the switching frequency is reduced to limit switching losses. The combination of fixed

frequency operation at high output power and frequency reduction at low output power

provides high-efficiency over the total load range.

The TEA1733LT/N1 enables low cost, highly efficient and reliable supplies for power

requirements up to 75 W to be designed easily and with a minimum number of external

components.

2.1 Features

 SMPS controller IC enabling low-cost applications

 Large input voltage range (12 V to 30 V)

 Very low supply current during start-up and restart (typically 10 A)

 Low supply current during normal operation (typically 0.5 mA without load)

 Overpower or high/low line compensation

 Adjustable overpower time-out

 Adjustable overpower restart timer

 Fixed switching frequency with frequency jitter to reduce EMI

 Frequency reduction with fixed minimum peak current to maintain high-efficiency at

low output power levels

 Slope compensation for CCM operation

 Low and adjustable OverCurrent Protection (OCP) trip level

 Adjustable soft start operation

 Two protection inputs (e.g. for input UVP and OVP, OTP and output OVP)

 IC overtemperature protection