A medical power supply is a specialized type of power supply designed to provide conditioned outputs for medical devices, instruments, and equipment. These power supplies are built to meet the stringent safety standards of IEC 601(EN60601) & UL60601, which are specifically tailored for electrical, medical, and dental equipment intended for professional use. Compliance with these standards ensures the reliability and safety of the devices, which is paramount in the medical field. Medical power supplies are categorized as "medical-grade" when they satisfy these standards and are designed to isolate the patient from any electrical signals, a critical feature in medical applications.
Medical power supplies typically require longer design cycles compared to commercial devices, and they often have a longer life expectancy, necessitating vendor support for many years. They are available in various form factors, including open frame, enclosed frame, modular, and encapsulated designs.
There are two main types of medical power supplies:
Linear Power Supplies:
These accept AC inputs and provide one or more DC outputs. They use an active element, usually a power transistor, operating in its linear region to generate the desired voltage. The output voltage is regulated by dropping excess input power in ohmic losses (heat) in a series dissipative component, such as a resistor or a transistor. Linear power supplies are known for their excellent regulation, very small ripple, and very little output noise.
Also known as switch-mode products or switching mode power supplies (SMPSs), these use a switching element or regulator to generate the desired voltage. They incorporate electronic components that continuously switch ON and OFF at a very high frequency, connecting and disconnecting energy-storing devices (inductors or capacitors) to and from the input source voltage or the output load. SMPS designs result in high power density (smaller size for the same power output) and reduced power consumption (higher efficiency) compared to linear power supplies.
Medical power supplies are used across a wide range of applications, including diagnostic equipment, medical monitoring devices, laboratory instruments, and home patient and dental care equipment. Examples of such applications are medical imaging, CT scanners, ultrasound, blood analysis, blood pressure monitors, ECG, EEG, chemical analysis, lab automation, medical beds, CPAP, infusion pumps, dental chairs, dental LCD displays, and oral care equipment.
