AN780 MICROCHIP [Microchip Technology], AN780 Datasheet
AN780
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AN780 Summary of contents
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... – Analog Switch Control Signals 2 16 – AN780 approximately equal INT (max) INT INT INT INT IN Control Logic A B Converter State 0 0 Zero Integrator Output 0 1 Auto-zero 1 0 Signal Integrate 1 1 Deintegrate ...
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... AN780 10k 100k V IN+ .01u V IN– 100k LM285-2.5 Analog Ground *C recommended Polypropylene INT FIGURE 2: TC500A and TC520 The 16-bit conversion result is accumulated in the TC520 along with a polarity bit and an overrange bit. These bits are formed into one 18-bit serial word which may be read at any rate and at any time ...
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... R /R REF REF TOTAL + – (V – INT SG + – (V – REF/ TOTAL AN780 = INT TOTAL REF has been replaced by an expression for the IN ), the strain gage constant ( INT INT BUF ...
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... AN780 AUTO-ZERO AND REFERENCE CAPACITORS The voltage on these capacitors stay very constant so dielectric absorption is not a consideration. The long integration time does require capacitors with very low leakage. A .68 F polyester capacitor was used in both cases. TC520 TIMING A 200ms integration time is already selected. There are a few options available with the TC520 to do this ...
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... FIGURE 4: Kilogram scale schematic. © 2002 Microchip Technology, Inc. 74HTTC244 PIC16C62A TC520 TC500A AN780 DS00780A-page 5 ...
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... AN780 READ D OUT OUT OVR POL MSB Read Format D CLK LOAD D Load Format MSB IN D CLK FIGURE 5: Serial interface protocol. REFERENCE VOLTAGE CALCULATION Now that the timing has been determined, eq3 can be used to calculate the reference voltage (max REF ...
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... Add Delta to Register Low Register Overflow Reset Polarity Bit Retrieve Saved Reading Deintegrate Multiply by 22046 Set Overrange Bit Yes FIGURE 7: PIC16C62A program flow chart. AN780 Start Setup Conversion No Complete ? Yes Read Conversion Results from TC520 Save Results as Offset Value 15 Times ? Yes ...
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... AN780 NOTES: DS00780A-page 8 2002 Microchip Technology Inc. ...
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Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates your responsibility to ensure that your application meets with your specifications. No representation or warranty is ...
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