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How to protect ADC input from overvoltage?
A way of eliminating overvoltage issues completely is to use a single-supply rail for the amplifier. This means the driving amplifier can never swing below ground or above the max input voltage if the same supply level is used as for the reference voltage (max input voltage), which is 5 V in this example.
What is ADS1115?
ADS1115 is an ultra-small, low-power, 16-bit precision AD converter (Analog to Digital Converter) with an internal reference voltage. Mainly used in high-precision instrumentation, automotive electronics, battery voltage collection and other high-precision collection occasions.
How does a clamping diode work?
The clamping circuit fixes the voltage lower limit to zero, that is, the start of the signal is 0 V. The positive clamping circuit blocks the input signal when the diode is forward biased. During the negative half cycle of an AC signal, the diode is forward biased and allows electric current through it.
What are different types of ADC?
Main Types of ADC Converters
- Successive Approximation (SAR) ADC.
- Delta-sigma (ΔΣ) ADC.
- Dual Slope ADC.
- Pipelined ADC.
- Flash ADC.
Where is ADC used?
An analog-to-digital converter (ADC) is used to convert an analog signal such as voltage to a digital form so that it can be read and processed by a microcontroller. Most microcontrollers nowadays have built-in ADC converters. It is also possible to connect an external ADC converter to any type of microcontroller.
How does the ads1115 16-bit ADC work?
Normally you would need two inputs to switch between 4 addresses but the ADS1115 16-bit ADC uses a clever scheme. The single address input is sampled continuously and if you connect it to GND, VDD, SDA or SCL you can set the address from 0x48, 0x49, 0x4a, 0x4b respectively.
How to protect ADC inputs from overvoltage?
A common issue that arises when designing an ADC circuit is how to protect the ADC inputs from overvoltage. The protection of ADC inputs has many scenarios and potential solutions. ADCs from all vendors have similar needs in this respect.
What can ads1115 be used for in a microcontroller?
This ads1115 tutorial shows you how to setup the libraries to drive the chip, and take readings using different PGA gain settings. It also covers how the device is able to measure negative voltageeven though it only operates using a single supply. This makes it useful as a current sink or source measuring device.
How does the series resistor protect the ADC?
The series resistor after the Schottky diodes also helps limit the current into the ADC if the internal diodes turn on slightly. For extra protection, if the reference has little to no sink current capability, a Zener diode or clamp circuit could be used on the reference node to guarantee the reference voltage cannot be pulled too high.