This article shows how to produce negative output voltages from positive input voltages using the MAX17501 and MAX17502 synchronous step-down converters. By Dipankar Mitra:
Industrial control equipment such as programmable logic controllers, I/O modules, mass flow controllers, and various other sensors and supporting systems use analog components like amplifiers and multiplexers that operate on negative supply voltage. Typically operating at ±12V, ±18V or other variations, these voltages are generated from a 24V DC bus. Maxim’s portfolio of high-voltage synchronous buck regulators offer 50% lower power loss allowing customers to operate their equipment 50% cooler. In this application note, we discuss techniques to use these synchronous buck regulators to generate negative voltages.
AppNote: How to Use the MAX17501 and MAX17502 for Negative Output Voltage Applications - [Link]
Engineers at the University of California, Berkeley, have shown that it is possible to reduce the minimum voltage necessary to store charge in a capacitor, an achievement that could reduce the power draw and heat generation of today’s electronics. Shown is a rendition of an experimental stack made with a layer of lead zirconate titanate, a ferroelectric material. UC Berkeley researchers showed that this configuration could amplify the charge in the layer of strontium titanate, an electrical insulator, for a given voltage, a phenomenon known as negative capacitance.
“Just like a Formula One car, the faster you run your computer, the hotter it gets. So the key to having a fast microprocessor is to make its building block, the transistor, more energy efficient,” said Asif Khan, UC Berkeley graduate student in electrical engineering and computer sciences. “Unfortunately, a transistor’s power supply voltage, analogous to a car’s fuel, has been stuck at 1 volt for about 10 years due to the fundamental physics of its operation. Transistors have not become as ‘fuel-efficient’ as they need to be to keep up with the market’s thirst for more computing speed, resulting in a cumulative and unsustainable increase in the power draw of microprocessors. We think we can change that.” [via]
Negative capacitance – one day soon - [Link]
Two models will be shown, one full-wave rectified and the other a half-wave rectified negative ion ionizer. Featuring an optional fan on the full-wave model.
Benefits of negative ions supposedly include
• freshen and purify the air
• help lift mood
• alleviate depression including winter depression(SAD)
• eliminate most tiny particles suspended in the air (indoors)
How to Make a Negative Ion air ionizer – [Link]
Simple negative power supply (-5V / -12V / -15V) Sometimes you need a simple negative power supply. The best example is the contrast PSU for common small LCD device. Building -5V from a battery or a wallmart supply isn’t really easy.Here is a simple design small device that is able to provide -5V, -12V, -15V. He used the MAX 764/765/766 series. [via]
Simple negative power supply (-5V / -12V / -15V) – [Link]