Slash Power Dissipation with Maxim’s Industrial Protected Low-Side Digital Output Solution
Feb 23, 2021
| By: Josh Fankhauser
Business Manager, Industrial Communications, Maxim Integrated
Industrial systems around the world face the ever-present pressure to evolve and innovate to keep pace with competition and satiate growing customer demands. As factory floors become more intelligent and production flows are optimized, size and reliability become critical issues in every system.
Automated factories utilize programmable logic controllers (PLCs) to manage the input and control of a multitude of sensors and output devices. PLCs employ digital outputs to drive or activate various high-voltage (24V+) loads on the factory floor such as relays, lamps, valves, and other actuators. Simply put, these digital outputs essentially act as electronically controlled ON/OFF switches. Depending on the system design, a PLC may use either high-side or low-side switches.
Traditionally, low-side switches have been more prevalent in Eastern industrial markets such as China & Japan, but as the globalization of technology continues, digital output module manufacturers are striving to expand their portfolios to address every available end market. Many low-side factory automation products today are comprised of non-optimized discrete solutions which, although cheap, struggle to meet the I/O density that many high-side modules are capable of due to the limitations posed by power and heat dissipation, alongside total solution size.
One other consideration to be made is that of the protections and reliability of a specific system. When high inductance loads are turned off, the energy of the coil must be allowed to dissipate via high-voltage clamps to avoid damage. Additionally, per channel surge and ESD protection is also often a necessity in digital input/output modules. Large, bulky discrete TVS arrays can provide robust protection, but majorly impact the form factor in high channel count designs. Finally, due to the complexity of many factory automation systems, load supply miswiring faults can occur.
In summary, some of the key challenges that need to be addressed when designing a PLC (or motor control) system include:
- Power dissipation: Reducing the power dissipation enables smaller enclosures and can ease the thermal budget.
- Reliability: Systems must be protected against a scope of hazards such as surge, ESD, inductive load kickback, miswiring faults, etc.
- Solution size: Large discrete components limit available board space and can decrease the available I/O density in the module.
Half the Power Dissipation in Half the Size
Maxim Integrated's newest addition to its digital input & output product family is the MAX14919. This industrial-protected, quad-channel low-side switch can decrease power dissipation up to 70% when compared to the competition due its low 140mΩ (typ) On-Resistance per channel. It features ±1kV/42Ω, 8µs/20µs integrated surge protection alongside ±8kV contact and ±25kV airgap ESD protections. Reverse current detection allows for protection against load-supply miswiring and internal high-voltage clamps enable fast load demagnetization. Packaged in a form factor friendly 6.5mm x 6.4mm footprint 20-pin TSSOP package, the MAX14919 offers an ideal solution for PLC, distributed control system (DCS), or motor control solutions looking to improve I/O density and compete with the highest levels of integration available in the market.
You can evaluate the MAX14919 for your next PLC, DCS, or motor control by buying the MAX14919EVKIT evaluation kit. The kit is available for $45, is fully assembled and tested, and is RoHS compliant.