How to Achieve Voltage Inversion: Detailed Guide to Positive and Negative Voltage Conversion Circuits

Introduction

Power converters play a vital role in industrial automation and electronic systems. Buck converters generally step down voltage, while boost converters increase voltage. As application demands evolve, voltage inversion techniques have become essential, especially in systems requiring coexistence of positive and negative voltages. Such designs are common in analog signal processing, telecommunications, and power control fields.

Positive to Negative Voltage Conversion

Many scenarios require inverting a positive voltage to negative—for instance, providing ±5V symmetrical supplies for operational amplifiers, ensuring precise signal conditioning, or safely turning off MOSFET gates. Figure 1 illustrates a simple inverter circuit based on a standard buck regulator. This transformerless design achieves stable negative output voltage via feedback resistor adjustment, offering compact structure and cost-effectiveness.

Negative to Positive Voltage Conversion

A typical negative-to-positive conversion application is in telecom systems converting -48 V to +48 V. Figure 2 shows an inverting boost converter employing a boost regulator IC for efficient negative-to-positive voltage transformation. Careful design considerations include correct switching device polarity and control signal level shifting to maintain reliable operation.

LTC7899 Dedicated Controller – High-Performance Negative-to-Positive Conversion

For higher power applications, specialized synchronous boost controllers such as the LTC7899 significantly enhance design efficiency and performance. Supporting a wide voltage range (up to 135 V) and utilizing external MOSFETs, the LTC7899 enables high-efficiency synchronous conversion. Figure 3 demonstrates a LTspice simulation validating the application, facilitating faster prototyping for engineers.

Conclusion

Modern switching regulator technologies enable simple, efficient, and scalable voltage inversion without relying on traditional transformers. A variety of circuit topologies and dedicated ICs offer designers flexible solutions for diverse needs. Leading-edge controllers like the LTC7899 empower innovation and upgrades in industrial automation and telecommunication power systems.