Linear Built-in Circuits Purposes
Within the earlier chapter, we mentioned about what an ADC is and the examples of a Direct kind ADC. This chapter discusses concerning the Oblique kind ADC.
If an ADC performs the analog to digital conversion by an oblique technique, then it’s referred to as an Oblique kind ADC. Usually, first it converts the analog enter right into a linear perform of time (or frequency) after which it should produce the digital (binary) output.
Twin slope ADC is the perfect instance of an Oblique kind ADC. This chapter discusses about it intimately.
Twin Slope ADC
Because the identify suggests, a twin slope ADC produces an equal digital output for a corresponding analog enter by utilizing two (twin) slope method.
The block diagram of a twin slope ADC is proven within the following determine −
The twin slope ADC primarily consists of 5 blocks: Integrator, Comparator, Clock sign generator, Management logic and Counter.
The working of a twin slope ADC is as follows −
- The management logic resets the counter and permits the clock sign generator with the intention to ship the clock pulses to the counter, when it’s acquired the beginning commanding sign.
- Management logic pushes the swap sw to hook up with the exterior analog enter voltage , when it’s acquired the beginning commanding sign. This enter voltage is utilized to an integrator.
- The output of the integrator is related to one of many two inputs of the comparator and the opposite enter of comparator is related to floor.
- Comparator compares the output of the integrator with zero volts (floor) and produces an output, which is utilized to the management logic.
- The counter will get incremented by one for each clock pulse and its worth will probably be in binary (digital) format. It produces an overflow sign to the management logic, when it’s incremented after reaching the utmost rely worth. At this instantaneous, all of the bits of counter will probably be having zeros solely.
- Now, the management logic pushes the swap sw to hook up with the unfavorable reference voltage . This unfavorable reference voltage is utilized to an integrator. It removes the cost saved within the capacitor till it turns into zero.
- At this instantaneous, each the inputs of a comparator are having zero volts. So, comparator sends a sign to the management logic. Now, the management logic disables the clock sign generator and retains (holds) the counter worth. The counter worth is proportional to the exterior analog enter voltage.
- At this instantaneous, the output of the counter will probably be displayed because the digital output. It’s virtually equal to the corresponding exterior analog enter worth .
The twin slope ADC is used within the purposes, the place accuracy is extra essential whereas changing analog enter into its equal digital (binary) knowledge.