Juno Lighting, Inc.

James A Rekowski

David Schie

This invention allows conversion from AC or DC line voltage between 70 and 424 volts to small loads between 2.5V and 18V DC for charging of batteries and operating of small loads. The invention uses a topology including two flyback stages in tandem. This invention has many uses and we are believed to be the first to apply it to battery charging and the operation of small loads. The invention is very cost effective and has feedback both from the input line voltage and output voltage to allow different loads and to allow the universal voltage input. The invention operates at high frequency and thus eliminates large transformers and uses surface mount components. All of this results in its very small size, low heat generation, and high efficiency. The invention draws very little power when connected only to a battery without the AC having been cycled. Primary applications for this invention include low powered uninterrupted power supply (UPS) devices. As disclosed herein, our first application is an emergency lighting device combined with an exit sign. However, we may use the same power supply for lighting equipment, lighting sensors, smoke detectors, burglar alarms, passive receivers, infrared detectors, ultrasonic detectors, stand-alone battery chargers, communications equipment or any other device which has a small load or requires charging with a battery from high input line voltages, such as 120V and higher.

Exit sign having a pulse switching tandem flyback voltage converter and

The power supply converts a high wide ranging AC or DC voltage into a low regulated output voltage. Input rectifiers and filters are provided to rectify and filter the AC and to pass the DC voltage. An integrated switching circuit converts the filtered DC voltage into brief pulses whose duty cycle is varied by a first regulator as an inverse function of the filtered DC voltage. The pulses are employed to produce a DC output voltage by a tandem flyback circuit connected to the filtered DC voltage and comprising an electronic switch connected in series with a first inductor across the filtered voltage and having a gate supplied with the pulses, a capacitor and a first diode connected in series across the first inductor for receiving the discharge thereof, a second inductor and a second diode connected in series with the electronic switch and the capacitor whereby the capacitor is discharged through the second inductor, and output rectifier and a filter connected across the second inductor to produce a filtered DC output, a secondary winding coupled to the second inductor and connected through a rectifier and a filter to supply DC operating voltage to the integrated switching circuit during normal operation, and a diode and a resister connected between the filtered high voltage DC and the integrated switching circuit to supply operating power thereto during start-up.

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Prospect Heights, IL, United States of America

James A Rekowski