Quieter AC-DC supply

Louise Smyth

TDK has added quieter 700 to 1200 Watt models to its QM series of modular AC-DC power supplies along with PMbus communications options.

The supplies have low acoustic noise and body floating (BF) ready isolation for medical and industrial safety applications, including BF rated medical equipment, test and measurement, broadcast, communications and renewable energy applications.

The new QM enclosures measure 127 x 63.3 x 270 mm long and deliver 1200W at 180-264Vac and 700W with a wide range input of 90-264Vac.

Up to 12 outputs can be configured using single and dual output modules with voltages from 2.8V to 61.6V. An optional standby/signal module can be selected with a choice of one or two standby voltages (5V, up to 2A and 12V at 1A), unit inhibit or unit enable, an AC Good signal and a PMBus interface.

The units will operate in ambient temperatures of -20 to +70°C, derating the output power and output current by 2.5% per °C above 50°C.

The QM operating efficiency is up to 91% and as this reduces the power consumption and heat generated, a low speed, quieter fan can be used.

This also increases reliability as less dirt and contaminants are drawn into the power supply, enabling a seven-year warranty.

The units are certified to IEC/EN/UL/CSA 60601-1, ANSI/AAMI ES 60601-1, IEC/EN/UL/CSA 60950-1, is designed to meet IEC/EN 61010-1 and has the CE marking for the Low Voltage and RoHS2 Directives.

With an input to output isolation of 4,000Vac (2 x MOPPs), 1,500Vac input to ground (1 x MOPP) and 1,500Vac (1 x MOPP) output to ground, the series can be used in BF rated medical equipment.

The QM series has a maximum earth leakage current of 300µA, while still complying with the EN61000-6-3:2007 and EN60601-1-2:2015 (curve B conducted and radiated) emission standards.  The units also meet the EN60601-1-2 and EN61000-6-2 immunity standards.

TDK has also added a standby/signal option with a PMBus communications interface for the QM series.

This can be used to improve system-level power management in medical equipment, test and measurement, broadcast, communications and renewable energy applications.

The PMBus module allows developers to inhibit or enable all the QM output voltages with a single command, monitor the inlet temperature, review fan speed and status, monitor run-time and determine manufacturing related data.

Up to 8 units can be connected to a single PMBus controller.

The standby/signal option also contains a 5V/2A standby voltage (always present when AC power is applied to the power supply), and a fan-fail warning signal indicating that a fan has stopped, is slowing down or running too fast indicating a blockage.