Voltmeter and Ammeter Training Camp

I. Design Background
Participating in the CW32 Voltage and Current Meter Training Camp to
become familiar with LCSC EDA and Chipsource Semiconductor's CW32 products.
In electronic systems, voltage and current are two fundamental quantities of analog signals. To process these analog signals in digital systems, we need to use an ADC to convert them into digital signals.
ADC, short for Analog-to-Digital Converter, is used to convert analog signals (usually continuously changing voltage or current) into digital signals (usually binary code).
II. Overall Solution

III. Design Summary

1. Power Supply Circuit
LDO (Low Dropout Linear Regulator) Selection
This project uses an LDO as the power supply. Considering that most voltage meter products are used in industrial scenarios with 24V or 36V power supplies, this project selected the SE8550K2, which has a maximum input voltage of up to 40V, as the power supply. The main reason for not using a DC-DC buck converter to handle the large voltage drop is to avoid introducing DC-DC ripple interference during the design process; a secondary reason is to reduce project costs.
2. MCU Selection Analysis
3. Voltage Sampling Circuit
4. Current Sampling Circuit:
INA199A1DCKR was selected here to amplify the current sampling by 50 times before measurement.
5. OLED Display
6. LED Indicators:
This section includes a power indicator and an IO operation indicator.
7. Button Circuit Design
: Buttons are used for overcurrent settings: KEY1 sets overcurrent to -, KEY2 sets overcurrent to +, and KEY3 restores the default 200mA overcurrent setting. KEY1 and KEY2 have long-press and short-press functions.
IV. Overall Design Block Diagram

V. Program Flowchart
(Refer to Appendix)
VI. Physical Demonstration VII.

Precautions

VIII. Demonstration Video

(See Appendix)