Next-Gen Power Management ICs for Industrial Automation

Industrial automation equipment, including PLCs, remote I/O modules, motor drives, sensors, and human-machine interfaces, places demanding requirements on power management. Supplies must tolerate wide input ranges and harsh transients, operate over extended temperatures, keep electromagnetic emissions low, and often report their own health. Recent generations of power management ICs (PMICs) and regulators address these needs with higher integration, better protection, and more diagnostic capability.

The Industrial Power Environment

Most factory equipment is powered from a nominal 24 V DC bus. In practice, that bus can vary widely and carry disturbances from long cables, inductive loads, and switching equipment. Designers typically need to handle:

• Wide input range: regulators rated well above 24 V, often 40 V to 60 V or more, to survive surges and transients.
• Surge and burst immunity: tests such as IEC 61000-4-4 (electrical fast transient) and IEC 61000-4-5 (surge) define stresses that the input stage must survive.
• Reverse polarity and miswiring: field wiring mistakes should not destroy the module.
• Extended temperature: enclosed cabinets and compact modules can run hot, so derating and thermal design matter.

Wide-Input Synchronous Buck Converters

Stepping 24 V down to 5 V, 3.3 V, or lower rails is the most common power task in industrial electronics. Modern wide-input synchronous buck converters integrate both power MOSFETs, compensation, and protection, which reduces board area compared with older non-synchronous designs using external diodes.

Examples include TI's LMR36015 and related LMR33x/LMR36x families, and ST's L6983 and similar synchronous buck converters. When comparing these devices, consider:

• Light-load efficiency: many modules spend most of their time at low load, so pulse-frequency or auto mode operation can reduce standby power.
• Quiescent current: important for always-on rails and for designs that must meet a tight power budget per I/O channel.
• EMI features: spread-spectrum frequency modulation, controlled switching edges, and pinouts that minimize hot loop area help pass conducted and radiated emissions limits.
• Minimum on-time: this determines whether a converter can regulate a high step-down ratio at a given switching frequency.

eFuses and Input Protection

Traditional input protection used fuses, TVS diodes, and discrete reverse-polarity circuits. Electronic fuses (eFuses) and hot-swap controllers integrate many of these functions into one device, with adjustable current limit, overvoltage cutoff, reverse current blocking, and thermal shutdown. TI's TPS2660 is an example of an industrial eFuse designed for 24 V systems. Benefits include predictable fault behavior, automatic or latched recovery, and fault indication that the system controller can read.

A TVS diode is usually still required ahead of the eFuse to clamp fast surge energy, so the two components should be selected together.

Multi-Rail PMICs for Processors and FPGAs

Controllers and gateways increasingly use application processors or FPGAs that need several rails with defined sequencing, voltage tolerance, and power-good monitoring. Dedicated PMICs designed alongside specific processors simplify this. Examples include NXP's PCA9450 for i.MX 8M family processors and TI's TPS65218 for certain Sitara processors. Using the PMIC recommended in the processor's reference design reduces risk with sequencing, DDR power, and low-power modes.

Configurable PMICs with one-time programmable or I2C-adjustable settings allow one hardware design to support different processor variants, but the programmed configuration must be specified correctly when ordering.

Isolated Power and Signal Isolation

Industrial I/O often requires galvanic isolation between field-side circuits and logic. Isolated DC-DC converters, transformer drivers, and integrated isolated power modules supply the field side, while digital isolators handle data. Selection should consider isolation rating, working voltage, creepage and clearance, and the relevant safety standards for the end equipment.

Smart Load Switching and Digital Outputs

PLC digital outputs drive solenoids, relays, and lamps. Intelligent high-side switches, such as ST's IPS family, integrate current limiting, thermal protection, and inductive load demagnetization, and provide diagnostic feedback for open-load or short-circuit conditions. This reduces external components and improves the ability to detect field faults.

Telemetry and Predictive Maintenance

A growing number of power ICs offer digital interfaces such as I2C or PMBus to report input voltage, output current, temperature, and fault history. In automation systems, this data supports predictive maintenance by revealing trends such as rising temperature or increasing load current before a failure occurs. Even where full telemetry is not needed, power-good outputs and fault flags routed to the controller improve diagnostics.

Selection Checklist

1. Confirm the absolute maximum input voltage covers expected transients with margin.
2. Check efficiency at both full and typical load, not only peak efficiency.
3. Review EMI features and the layout guidance in the datasheet.
4. Verify the operating temperature grade, often -40 °C to 105 °C or 125 °C for industrial use.
5. Check protection functions: current limit, thermal shutdown, undervoltage lockout, and reverse polarity handling.
6. Review lifecycle status and whether pin-compatible alternatives exist.

Summary

Next-generation power management ICs bring wide input range, integrated protection, low EMI, and diagnostic capability to industrial automation. Choosing the right combination of buck converters, eFuses, PMICs, isolation, and smart switches improves reliability and simplifies compliance with industrial standards.

XINJIEDA can help source power management ICs from ST, TI, and NXP, or review a power-section BOM for availability and alternatives.