Medical devices need to include reliable and safe power supplies to ensure they function properly and protect both operator and patient. Overvoltage protection (OVP) is a critical safety measure for medical devices. We’ll talk about what OVP is and what medical device manufacturers should consider when choosing a safe and compliant power supply.
What is Overvoltage Protection (OVP)?
Overvoltage happens when the voltage applied to a device exceeds the rated maximum. If overvoltage is a recurrent problem, it can result in component damage, device failure, and even safety hazards for people on both sides of the device.
OVP circuits are part of devices to prevent excessive voltage from reaching vulnerable parts of a medical power supply. Protection circuits include different components to accomplish this, including:
- Overvoltage relays: When input voltages exceed a prescribed threshold, overvoltage relays can disconnect the load from the power source.
- Zener diodes: These devices provide a constant voltage output, regardless of the voltage they’re receiving. Diodes conduct when the input voltage exceeds the Zener voltage. This directs excess current away from the load.
- Transistor-based circuits: Transistor-based circuits can offer more precise control compared to Zener diodes, regulating the output voltage as it comes in.
Why is Overvoltage Protection Important?
Overvoltage protection is important for patient safety, equipment reliability, and regulatory compliance. Medical devices that malfunction can put patients and medical professionals in danger. OVP keeps devices from failing while simultaneously protecting patients. When equipment fails, it can be expensive to repair or replace. OVP also reduces the need for these extra expenses. Finally, all medical devices must abide by strict safety standards, including regulations around overvoltage protection. To sell in markets like the United States, OVP is part of the requirement.
Types of OVP
Medical power supplies may include clamping circuits, crowbar circuits, or electric fuses as part of overvolt protection. Clamping circuits use voltage-limiting components, such as Zener diodes, to clamp the output voltage and keep it at a safe level. Crowbar circuits use a Zener diode and a transistor to create a short circuit across the load. This happens when voltage goes beyond a set threshold. Electronic uses use electronic components for overcurrent protection, which can also aid in preventing overvoltage.
Designing for Overvoltage Protection
To achieve successful OVP, medical device power supplies have to provide the following:
- Activation at a voltage level below the maximum-rated voltage of the device
- Quick response to overvoltage events to keep device damage at a minimum
- Reliable OVP circuits so safety is ensured in critical moments
- Regulatory compliance with all applicable safety standards
What should you look for in power supply protections?
The seven protections for power supplies medical device manufacturers should look for include OVP, as well as these other measures:
- Overcurrent protection (OCP)
- Overpower protection (OPP)
- Undervoltage protection (UVP)
- Short-Circuit Protection (SCP)
- Over-Temperature Protection (OTP)
- Surge and Inrush Protection (SIP)
RAM Technologies provides all 7 forms of protection with our medical PC-based power supplies. Our product pages have more information on the specifics of our medical-grade power supplies. You can also contact us with any questions about customizations or protections 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
Overpower Protection and Medical Power Supplies
