Comparator challenge (FPGA)

This task would typically be performed by an external comparator, and the comparator output (a logic level) routed to the FPGA.

What are you trying to do? Perhaps I can offer an alternative solution.

Cheers,

Dave

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This task would typically be performed by an external comparator, and the comparator output (a logic level) routed to the FPGA.

What are you trying to do? Perhaps I can offer an alternative solution.

Cheers,

Dave

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Trying to design temperature sensor, it would require varying input voltage at some comparator. The design ought to be typically digital and inbuilt in the FPGA, so using an external comparator would not be an alternative. Do u think a voltage-to-frequency converter using linear voltage controlled oscillator would suffice???

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Trying to design temperature sensor, it would require varying input voltage at some comparator.

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Why would you try to design a temperature sensor, when there are very good parts already available?

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The design ought to be typically digital and inbuilt in the FPGA, so using an external comparator would not be an alternative. Do u think a voltage-to-frequency converter using linear voltage controlled oscillator would suffice???

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This design would require an external voltage-to-frequency converter, so that breaks your idea to keep everything digital.

If the goal is to sense DC voltages using an FPGA, then you can use an LVDS receiver to build a sigma-delta converter, however, I'm not sure how accurate it would be.

It sounds to me like you are making more complicated than they need to be.

Cheers,

Dave

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Why would you try to design a temperature sensor, when there are very good parts already available?

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We are trying out something different, never mind.

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If the goal is to sense DC voltages using an FPGA, then you can use an LVDS receiver to build a sigma-delta converter, however, I'm not sure how accurate it would be.

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Building a sigma-delta converter is a trival task, anything simpler??? perhaps a voltage-to-frequency converter?? But if a sigma-delta is used will it keep design digital???

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Building a sigma-delta converter is a trival task, anything simpler??? perhaps a voltage-to-frequency converter?? But if a sigma-delta is used will it keep design digital???

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No, there is no way to measure an analog voltage with an FPGA without using some external components.

The sigma-delta method relies on an external RC filter and an LVDS receiver, so the external components are simple; Google "Lattice RD1066" for an example.

A voltage-to-frequency converter is essentially a VCO, i.e., it has an analog input and a logic output, at that point you may as well use an ADC.

Cheers,

Dave