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TIDM-02008: TIDM-2008 Bus Voltage Sensing

Part Number: TIDM-02008


In Design Guide:TIDM-2008, section 2.2.2,  bus voltage is sensed by resistor divider network.

This sense circuitry has high impedance because of voltage divider with large R values.

Should an Op-Amp as buffer used? 

Similarly, section 2.2.1,  input AC  voltage is sensed by resistor divider network, but application did not use opamp as a buffer.

  • Hello,

    Yes, using an op-amp will give better signal band width. But in this case the frequency of AC voltage sensed is  60Hz and DC bus voltage which was assumed reasonably stable. So, the voltage will track close enough to the input already. Hence the need of an op-amp is not mandatory unless we need better signal band width.