General description

The TEA1738(L) is a low cost Switched Mode Power Supply (SMPS) controller IC intended for flyback topologies. The TEA1738(L) operates in peak current and frequency control mode. Frequency jitter has been implemented to reduce ElectroMagnetic Interference (EMI). Slope compensation is integrated for Continuous Conduction Mode (CCM) operation.

The TEA1738(L) IC 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), output OverVoltage Protection (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 TEA1738(L) 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.

Features and benefits

Features

■ SMPS controller IC enabling low-cost applications

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

■ Integrated OverVoltage Protection (OVP) on pin VCC

■ Very low supply current during start-up and restart (10 μA typical)

■ Low supply current during normal operation (0.55 mA typical 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 at medium power operation to maintain high efficiency

■ Frequency reduction with fixed minimum peak current at low power to maintain

high efficiency at low output power levels

■ Frequency increase at peak power operation

■ Slope compensation for CCM operation

■ Low and adjustable OverCurrent Protection (OCP) trip level

■ Adjustable soft start

■ Two protection inputs (e.g. for input UVP and OTP)

■ IC overtemperature protection

Applications

■ All applications requiring efficient and cost-effective power supply solutions up to 75 W.