This document describes how to implement a 10-bit Sigma-Delta A/D converter using a simple external circuit and a Sigma-Delta conversion program. The ST7FLITE05(09) has an on-chip ADC with 8-bit resolution and an input range of 0-VCC. The external Sigma-Delta ADC described in this application is designed for relatively slow alternating signals (0,2 - 5Hz) in the range 0 - 10mV(p-p). The focus of the project is to provide good relative accuracy, repeatable parameters and simplicity, resulting therefore a low cost of the device (in its simplest form, apart from the microcontroller, only three RC elements are necessary).
This document details the implementation of a 10-bit Sigma-Delta Analog-to-Digital Converter (ADC) using the ST7FLITE05/09 microcontroller. The solution is designed for relatively slow alternating signals (0.2 - 5Hz) in the range of 0 - 10mV peak-to-peak. The approach utilizes a simple external circuit consisting of only three RC elements alongside the microcontroller to achieve good relative accuracy and low cost.
| Resolution | 10-bit |
|---|---|
| Input Range | 0 - 10mV(p-p) |
| Signal Frequency | 0.2 - 5Hz |
| Conversion Period | 51.2ms |
| Interrupt Period | 50us |
| External Components | three RC elements |
To describe how to implement a 10-bit Sigma-Delta A/D converter using a simple external circuit and a Sigma-Delta conversion program.
It is designed for relatively slow alternating signals between 0.2 and 5Hz with a voltage range of 0 to 10mV peak-to-peak.
Only three RC elements are necessary in the simplest form, apart from the microcontroller.
The result is achieved every 51.2ms, which corresponds to 1024 interrupts.