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What is the evolution of power supplies?
Since the advent of solid-state electronic power supplies (around 1950s) there has been very rapid development in power supplies.
- Solid‑state rectification and regulated linear supplies (1950s → 1970s)
Semiconductor diodes and later transistors made rectification and regulation cheaper, smaller, and more reliable.than the previous vacuum-tube power supplies.
Linear regulators (series pass elements) provided low‑noise outputs but dissipated heat proportional to voltage drop × current. This means poor efficiency. - Rise of switching‑mode power supplies (SMPS) (1960s → 1980s → mainstream by 1990s)
Key idea: Rectify the input ac, then chop DC at high frequency, using much smaller inductors/transformers, then rectify/filter. This brings large efficiency and size advantages over linear supplies.
Benefits: much higher efficiency (often 80–95% vs 30–60% for equivalent linear designs), much smaller size and weight, higher power density.
Result: SMPS rapidly displaced linear supplies in computers, TVs, telecom, industrial power. - Efficiency and power factor correction (1990s → 2000s)
Power Factor Correction (PFC) circuits (passive then active) became common to reduce harmonics and meet regulations.
Research and design evolution (partly driven by legislation) pushed designs toward 80–94% efficiencies across load ranges. - Power semiconductors and switching frequency evolution (1990s → present)
Devices moved from BJTs to MOSFETs to IGBTs for higher power and faster switching.
There is now an industry shift to wide‑bandgap semiconductors (GaN and SiC):. This brings lower losses, higher switching frequencies (MHz), higher temperature operation → smaller passives and higher density. - Digital control, telemetry, and modularity (2000s → present)
PWM controllers gave way to microcontrollers and DSPs for advanced regulation, multi‑rail sequencing, telemetry, adaptive switching, and soft‑start.
Server and telecom supplies became hot‑swappable, redundant; remote monitoring and smart power distribution increased. - Safety, EMI, and environmental drivers
EMI suppression, isolation, and safety standards (UL, CE, IEC) tightened designs.
Regulations on standby power, efficiency, and harmonic emissions pushed adoption of SMPS with PFC and low standby loss.
Current state-of-the-art and near future
- Widespread use of SMPS with digital control and active PFC; very high efficiencies (often >90%).
- GaN and SiC devices enabling smaller, lighter, higher‑frequency converters.
- DC distribution (48 V or higher) in data centers and buildings being explored to reduce conversions.
- More intelligence: networked power supplies with telemetry, predictive maintenance, and software‑defined power behavior.