Smart AC/DC low-dropout linear voltage regulator

23rd July 2019

Alex Lynn

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The TPS7A78 improves the overall efficiency and standby power in power supplies for an easy-to-use non-magnetic approach to AC/DC conversion. The TPS7A78 uses an external capacitor to create a current source and actively clamps the rectified voltage. The device then regulates the voltage down to the application-specific operating voltage.

The architecture of the device allows the standby power to be reduced from several 100s of milliwatts to just a few 10s of milliwatts. The TPS7A78 takes advantage of an innovative switched capacitor stage to reduce the clamped voltage down by approximately 1/4th of the value, which in turn multiplies the current by four. Thus, the current source capacitor can be much smaller in size, which minimises standby power, reduces solution size, and can lead to a lower system cost

The TPS7A78 is optimised for e-metering applications where the power supply must be reliable and magnetic tamper-proof. The TPS7A78 requires no external magnetics, which makes complying with IEC 61000-4-8 easier while minimising costly magnetic shielding in e-metering applications.

Additionally, the TPS7A78 also comes with a user-programmable power-fail detection threshold that can provide an early alert to power failures so the system can save data before completely losing power. A power-good indication can also be used for sequencing or to provide a reset to a micro-controller.

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

To learn more, click here.