Programmable DC Power Supply: Architecture and Protocols

Understanding modern power supply technology for industrial applications

Power Supply Architecture

Digital Control Architectures

SCPI, LXI, and Hybrid Topologies for Modern Labs.

In the modern electronics lab, the standalone "dumb" power supply is obsolete. As we embrace Industry 4.0, the Programmable DC Power Supply has evolved into the central nervous system of automated test benches.

What Makes a Power Supply "Programmable"?

For 2026 standards, a unit is only considered "Industrial Grade" if it supports specific bidirectional controls. It's not just about a digital screen; it's about the feedback loop.

  • Remote Sensing (Voltage Compensation)
  • List Mode (Waveform Generation)
  • Real-time Readback (V/I Telemetry)

Important Note

Many budget units claim to be "digital" but lack serial control. True industrial units (like the eTommens Series) allow full automation via PC/PLC.

SCPI and Connectivity

SCPI (Standard Commands for Programmable Instruments) is the universal language of ATE. Below is a standard connection sequence via RS232/LAN.

Connection Example
# Establishing connection to Power Supply...
> *IDN?
< ETOMMENS,ETM-3050,SN:2601001,V2.1
# Setting Voltage Limit to 24V
> VOLT 24.0
> CURR 5.0
# Enable Output
> OUTP ON
> MEAS:CURR?
< 4.982 A

SCPI over LAN

Standard for rack integration. Replaces legacy GPIB.

Modbus (RS485)

Best for PLC communication in noisy factory environments.

Topology Comparison

ArchitectureRipple/NoiseEfficiencyApplication
Linear (LDO)< 1mVppLow (40%)RF / Audio / Calibration
Switching (SMPS)> 10mVppHigh (90%+)Burn-in / Electroplating
Hybrid (2026)< 3mVppHigh (85%)Universal Lab Use

Data based on 2026 industry averages. Check eTommens datasheets for specific model specifications.

Summary

Automating repetitive voltage cycling tests saves hundreds of engineering hours. Ensure your equipment speaks the right language.

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