Medical devices play a vital role in healthcare settings every day, diagnosing, treating, and monitoring patients. However, these critical functions can be interrupted by power surges and inrush currents, causing data loss, malfunction, or even patient and operator harm. Surge and inrush protection (SIP) is a critical safety measure medical device manufacturers need to implement to mitigate risks associated with unpredictable currents. In this article, we’ll cover the importance of SIP in medical devices, protection techniques manufacturers might use, and key considerations for power supplies to ensure your product gets to market efficiently.
What is Surge and Inrush Protection (SIP)?
Surge and Inrush Protection (SIP) is a safety measure designed to protect electronic components in medical devices from damage that can be caused by sudden voltage spikes and high initial current surges. Transient events that cause surges and current inrushes can come from things like lightning strikes, power grid switching, or the initial powering on of a device.
Importance of SIP in Medical Devices
Medical devices perform at their best when they have access to reliable and uninterrupted power. Without protective measures in place to handle unexpected power events, devices may experience malfunctions, data corruption, component damage, or safety hazards.
Surges and current inrushes can cause medical devices to behave erratically or temporarily fail. Malfunctions from these events can lead to a loss of critical patient data or physical damage to sensitive components in the device. Surge events can also pose a risk to the safety of patients and operators, such as a shock hazard.
Requirements for Surge and Inrush Protection in Medical Devices
Medical electrical devices need to abide by regulatory standards, including IEC 60601-1, when implementing protective measures for patients and operators. This includes standards for surge and inrush protection. Requirements can include:
- Input overvoltage protection: Devices need to be able to handle transient overvoltage that comes in from power lines.
- Inrush current limiting: When powering on, devices should have mechanisms in place to limit the initial surge of current.
- Electrostatic discharge (ESD) protection: Protection measures need to be implemented against electrostatic discharges, which could otherwise damage sensitive components.
Types of SIP in Medical Devices
To prevent surge and inrush protection in medical devices, manufacturers may implement techniques including metal oxide varistors (MOVs), gas discharge tubes (GDTs), transient voltage suppressors (TVSs), and inrush current limiters (ICLs).
MOVs rapidly decrease resistance during high-voltage surges, diverting excess current away from sensitive circuitry and clamping the voltage to a safe level. GDTs also divert surge current away, but use a gas that ionizes and creates a low-resistance path for diversion. TVSs combine voltage clamping and current limiting for protection. Finally, ICLs provide temporary resistance when the power is first applied to the device.
Considerations for Medical Device Manufacturers when Choosing a Power Supply
When choosing a power supply for a medical device, manufacturers should consider its built-in surge and inrush protection capabilities, including its surge voltage rating and inrush current limiting mechanisms. Power supplies that already meet regulatory standards for IEC 60601-1 and relevant EMC standards can also make the path to getting the device approved by the FDA or another market more efficient.
Best Practices for Implementing Surge and Inrush Protection in Medical Devices
Effective implementation of surge and inrush protection for medical devices requires manufacturers to conduct thorough risk assessments, design with surge and inrush protection in mind, use reliable components in the construction of the device, and test and validate their device rigorously.
Surge and inrush protection needs to be considered alongside these six other forms of protection:
- Overcurrent protection (OCP)
- Overpower protection (OPP)
- Overvoltage protection (OVP)
- Undervoltage protection (UVP)
- Short-Circuit Protection (SCP)
- Over-Temperature Protection (OTP)
RAM Technologies offers all 7 forms of protection in our PC-based medical power supplies. Visit our product pages to learn more about our power supplies or contact us with any questions you have about protections and customizations we offer.
RAM Technologies’ power supplies are 60601-1 3.2 certified. When you’re designing your medical device and need help with a PSU, contact us for details.
More Resources:
What the FDA Moving to IEC 60601-1 3.2 Means for Manufacturers
7 Protections to Look For in a Power Supply
Undervoltage Protection (UVP) for Medical Devices
