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TPS7A78: Operating principle

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Part Number: TPS7A78

Hi,

Let me confirm the operating principle of TPS7A78.
① DC cut with Cs → Voltage drop with Rs
②Fit within 30V input range
③Input a voltage such as half-wave rectification to the AC+ (AC-) pin, and output the voltage at a low voltage with LDO.

Is my understanding correct?

Best regards,
Yuto Sakai

  • Hi Sakai-san,

    I may need more clarification on your questions. But here are my responses:

    ① DC cut with Cs → Voltage drop with Rs - The Cs Capacitor drops the AC line voltage and the internal active bridge produces a DC voltage at the SCIN pin., This voltage is ~(Vout+0.6V)*4 or 16V whichever is lower. 
    ②Fit within 30V input range - If used in DC mode, the input Voltage is 24VMax. While the device is 30V tolerant, operating at a higher voltgae would impact the long-term reliability of device.
    ③Input a voltage such as half-wave rectification to the AC+ (AC-) pin, and output the voltage at a low voltage with LDO.-The difference between Full-Bridge and Half-Bridge mode is simply made by grounding the the pin that does not have Cs and Rs in series with it. 

    John Cummings 蔣康明
    Texas Instruments 德洲儀器
    Johncummings@ti.com

    Please click the "Resolved" link at the bottom of this post if I have answered your question.

    Thank you,

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