Editing Basic Circuit Building Blocks
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== ADC Voltage Protection Circuit == | == ADC Voltage Protection Circuit == | ||
− | The input to an Analog to Digital Converter (ADC) has some issues that need a bit of attention. | + | The input to an Analog to Digital Converter (ADC) has some issues that need a bit of attention. One is that the input is normally quite sensitive to input voltages that are too high or too low. This circuit protects the ADC. ( Additionally it can provide amplification and a low impedance input to the ADC which can be quite helpful ) Note this is a specialization of '''Op amp Non Inverting Amplifier''' also on this page. |
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− | (Additionally | ||
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[[Image:Adc.png|thumb|800px|center]] | [[Image:Adc.png|thumb|800px|center]] | ||
− | * | + | *The opamp circuit is used to |
#provide a low input source resistance to the ADC | #provide a low input source resistance to the ADC | ||
− | #protect ADC | + | #protect ADC whose input signal may exceed the supply/reference voltage (i.e. INPUT > V<sub>cc</sub>) |
+ | *In scenario 2, the voltage into the ADC input pin is capped at the supply voltage. | ||
*Requirement for the op-amp: | *Requirement for the op-amp: | ||
**The op-amp can withstand the input signal beyond the supply voltage, provided that the input current is limited to I<sub>max</sub> (e.g. [http://focus.ti.com/lit/ds/symlink/opa4340.pdf OPA4340] I<sub>max</sub> = 10mA) | **The op-amp can withstand the input signal beyond the supply voltage, provided that the input current is limited to I<sub>max</sub> (e.g. [http://focus.ti.com/lit/ds/symlink/opa4340.pdf OPA4340] I<sub>max</sub> = 10mA) | ||
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More Information: | More Information: | ||
* [[input protection]] circuits | * [[input protection]] circuits | ||
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