Texas Instruments TPS7A7850PWPR

The TPS7A78 improves the overall efficiency and standby-power in power-supplies in aneasy-to-use, non-magnetic approach to AC/DC conversion. The TPS7A78 uses a capacitor-droparchitecture to lower the AC source voltage before actively clamping the rectified voltage. Thedevice then regulates this rectified voltage down to the application-specific operating voltage.The unique architecture of the device allows the standby power to be reduced to just a few 10s ofmilliwatts. The TPS7A78 switched-capacitor stage reduces power losses by stepping down therectified input voltage by a factor of four and increasing the output-to-input current by the sameratio, as given by P_IN ≅ P_OUT andV_IN ≅ V_OUT × 4. Compared to a traditionalcapacitor-drop (cap-drop) stage, this step down reduces input current, thus minimizing the value ofthe capacitance needed.

Electricity-metering applications, where the power supply must be reliable and magnetictamper-proof, benefits from using the TPS7A78 because this device does not require externalmagnetics. This feature makes complying with IEC 61000-4-8 easier while minimizing magneticshielding cost.

Additionally, the TPS7A78 also comes with a user-programmable, power-fail detectionthreshold that can provide an early alert to power failures and enable shutdown before completepower loss. The power-good indicator (PG) is also provided for sequencing or resetting amicrocontroller.

The TPS7A78 is available in a 14-pin HTSSOP (PWP) package.