multisupply

Multisupply refers to an electrical power supply arrangement that provides multiple output rails to power circuits with different voltage requirements. In electronics, common multisupply configurations include dual (±V) supplies, triple supplies, and multi-output supplies with several positive and negative rails. Such systems may be implemented as a single multi-output power supply or as multiple isolated supplies sharing a common reference.

Rails in a multisupply can be positive, negative, and ground, or include a virtual ground. A center-tapped transformer is a classic source for ± rails, while modern designs may use isolated DC-DC converters or switching regulators to generate additional rails. Regulation can be linear for low noise and low ripple or switching for higher efficiency, with sequencing and protection features to ensure safe startup and operation.

Advantages of multisupply include expanded dynamic range and headroom, the ability to bias different circuit blocks (for example, op-amps, analog front ends, and instrumentation) with appropriate voltages, and reduced noise transfer when digital and analog sections are isolated on separate rails. They also enable specialized biasing schemes and improved performance in precision electronics and audio equipment.

Challenges involve cross-regulation between rails, ground loops, and complex decoupling needs. Proper startup sequencing, load balancing, isolation where needed, and robust protection are important. Designers must also consider space, cost, EMI, and safety requirements when implementing multisupply solutions.

Typical applications include audio amplifiers, instrumentation and measurement equipment, laboratory power supplies, embedded systems with mixed analog/digital blocks, and RF transceivers.