Temperature to Digital converter
Created: Jan 21, 2016
No description available.
The reference design being shown is a simple temperature sensing circuit that uses LM35 as the sensing component and the ADC0804, which is the main component that digitalized the analog input. The ADC0804 is a CMOS 8-bit analog-to-digital converter that uses a differential potentiometric ladder. In this design, LM158 which is a two independent, high gain and internally frequency compensated general-purpose op-amp is used to be the one sending the reference voltage to the ADC0804.
The circuit starts to function when the LM35 sensed the change in temperature. The output of LM35 changed which is connected to the Vin (+) of ADC0804. The ADC0804 then compare the change of voltage to the reference voltage coming from LM158. The ADC0804 then interprets the difference of voltage and send the corresponding output state to 8-parallel data output. The LM158 is configured to be a voltage follower circuit so that the reference voltage will remain fixed and constant for the ADC to properly compare the change of voltage from the LM35. The output section can be a configured as LED, which turns on with the corresponding voltage coming from ADC0804, or it can be an LCD display or a seven-segment display.
This circuit design can be implemented as input to another circuit device that needs input that vary according to the temperature of the surroundings.