描述 Description

The TEA1938T is a member of the GreenChip family of controller ICs for switchedmodepower supplies. It is intended for flyback topologies to be used either standaloneor together with USB PD or smart charging controllers (like the TEA190x series) at thesecondary side. The built-in green functions provide high efficiency at all power levels.The TEA1938T is compatible with multiple output voltage applications with a wide outputrange from 5 V to 20 V in Constant Voltage (CV) mode. When used with a secondarysidecontroller IC, like the TEA190x series, it supports Constant Current (CC) mode downto 3 V output voltage.
At high power levels, the flyback converter operates in Quasi-Resonant (QR) mode. Atlower power levels, the controller switches to Frequency Reduction (FR) in DiscontinuousConduction Mode (DCM) operation. The peak current is limited to a minimum level.Valley switching is used in all operating modes.
At very low power levels, the controller uses a minimum-ripple burst mode to regulatethe output power. A special optocoupler current reduction regulation has been integratedwhich reduces the average optocoupler current in all modes to a minimum level. Thisreduction ensures high efficiency at low power and excellent no-load power performance.As the number of pulses per burst is kept at a minimum in this mode, the output ripple isminimized. For further efficiency optimization, the internal IC supply current is minimizedduring the non-switching phase of the burst mode.
The TEA1938T includes a wide set of protections that are safe-restart protections. Oneof these protections is an accurate OverPower Protection (OPP). If the output is shorted,the system stops switching and restarts. The output power is then limited to a lower level.The TEA1938T is manufactured in a high-voltage Silicon-On-Insulator (SOI) process.The SOI process combines the advantages of a low-voltage process (accuracy, highspeedprotection, functions, and control). However, it also maintains the high-voltagecapabilities (high-voltage start-up, low standby power, and brownin/brownout sensing atthe input).
The TEA1938T enables low-cost, highly efficient and reliable supplies for powerrequirements up to 75 W using a minimum number of external components.

特性 Features

General features
? SMPS controller IC supporting smart-charging applications and multiple-output-voltage applications
? Wide output range (5 V to 20 V in CV mode, 3 V to 20 V in CC mode, and 3 V to 6.5 Vin direct charging mode)
? Housed in a small SO10 package
? Adaptive dual supply for highest efficiency over the entire output voltage range
? Reduced optocurrent enabling low no-load power (20 mW at 5 V output)
? Fast transient response from 0 to full load
? Minimal audible noise and output voltage ripple in all operating modes
? Minimum ripple burst mode at very low power levels allowing the minimizing of the sizeof output capacitors
? Integrated soft start