In digital and communication circuits, certain communication interfaces such as the RS232 standard use positive and negative voltages to distinguish high and low logic levels: Logic 1 = -12 V, Logic 0 = +12 V. Negative voltages improve anti-interference performance for long cable transmission and suppress common-mode noise. This is a mandatory specification for industrial serial communication; the absence of negative voltage will result in garbled data and packet loss during communication.
Application Scenarios
Industrial PLC serial ports, RS232 ports for equipment debugging, differential communication modules, and data interaction for industrial control devices.
Key Technical Points
- Standard signal levels rely on ±10 V to ±12 V negative rails;
- On-chip charge pumps generate negative voltage from a single 5 V supply rail;
- Larger negative voltage levels deliver higher fault tolerance for long-distance transmission.
Further Reading on Negative Voltage Fundamentals
- Negative Voltage Basics: What Is Negative Voltage?
- Negative Voltage Basics: Voltages in Communication Circuits
- Negative Voltage Basics: Why Op-Amp & Audio Analog Circuits Require Positive/Negative Power Supplies
- Negative Voltage Basics: Charge Pump Implementations
- Negative Voltage Basics: Positive and Negative Voltage Design for Buck Circuits
- Negative Voltage Basics: Negative Rail Supply for Precision Op-Amp AC Signal Amplification