Bench Talk

Why does high-voltage innovation matter? It’s a question we hear frequently, and the answer may surprise you. Recently, my colleague Chris Schairbaum and I co-authored a white paper about how we are redefining power management through high-voltage innovation. Here, we have answered some of the more common questions we receive from customers about high-voltage.

 

Q: How can innovations in high voltage make a difference in the ever-increasing demand for electricity?

A: The goal of high-voltage innovation involves making the transmission and conversion of electrical power more efficient, so that less power is lost between the source and the end equipment. These innovations complement changes in electricity generation, such as introducing renewable energy sources, as well as energy-saving improvements in consuming equipment such as motors and refrigeration units. The result is a steady rise in power efficiency that saves money and helps reduce the release of greenhouse gases into the atmosphere.

Q: Where do semiconductors and integrated circuits (ICs) fit into the high-voltage equation?

A: Advanced semiconductors are among the most important technologies that have already been deployed and are being further developed to make power generation, transmission and consumption more efficient. Smart controls implemented using integrated circuits (ICs) and the use of new power semiconductor materials such as SiC and GaN enable us to convert and manage power with minimal losses. Furthermore, intelligent IC hardware enables power grids, factories, homes, cars and other systems to monitor, control and communicate system power usage efficiently. Finally power ICs, which are the backbone of power supplies and battery chargers, are an important factor enabling the mushrooming growth of portable electronics, creating convenience along with efficiency.

Q: Why focus on high voltages?

A: As power makes its way from the power source to the end application, every voltage conversion step involves a power loss. So power conversion is a prime area of opportunity. In addition, other conditions being equal, lower voltages lose a higher percentage of power in transmission than higher voltages. For these reasons, it is most efficient to bring high voltages close to, or even into, the end equipment before stepping them down with conversion methods that minimize power losses. The presence of high voltages in the vicinity of equipment and users also entails additional measures for machine protection and human safety.

Q: What type of power supplies should we be focused on for creating greater efficiency in high voltage?

A: Switched-mode power supplies (SMPSs) have gained ground in power conversion because they are inherently more efficient than traditional linear power supply designs. However, perfecting SMPS design is an ongoing art. These supplies create currents at high frequencies that must be prevented from propagating deep into the system and escaping back out into the source. Furthermore, operation of sensitive devices inside the power supply is susceptible to impedances from inside and interferences from surrounding components. For these reasons, SMPS solutions that integrate as much of the system as possible can help reduce the complexity of power supply design and help lower manufacturing costs. If the solution can include small-form-factor isolation along with the power circuitry, it is better because it effectively shields the system from outside interferences and prevents high frequencies from migrating from within the system onto the line.

Q: What kind of new materials are creating innovative opportunities in this space?

A: Manufacturers are turning to new materials such as gallium-nitride (GaN), built on a silicon substrate and silicon-carbide (SiC) to enable faster switching and even greater efficiencies at high voltages. Our company, in addition to its numerous silicon-based solutions, has developed several gate drivers for GaN switches and is starting to introduce advanced multichip modules (MCMs) that include both gate drivers and GaN power switches.

Q: How can MCMs help with rescaling high-voltage power supplies to fit on a board inside end equipment?

A: Whenever full system integration is not economical or prevented because the functions are built using different processes, integrating two or more devices in an MCM is a viable solution. Along with saving space, single-chip and MCM solutions increase power density and reduce the need for passive materials such as windings and heat sinks. The solutions also simplify design because they eliminate or minimize the complex internal impedances that make power supply design so difficult.

Q: How do you create precise control for gate drivers and power switches in SMPS settings?

A: At a minimum, the high frequencies of new SMPS designs call for digital control from high-performance state machines such as the UCD3138 controller. More flexible devices are C2000™ 32-bit microcontrollers (MCUs). Both devices deliver programmable timing control through multiple, high-resolution pulse-width-modulated (PWM) outputs. A single C2000 MCU or UCD3138 controller can handle closed-loop control of multi-stage power conversion and other system functions such as protection, measurement and communications. In addition to offering sophisticated timing techniques, these controllers feature high-resolution analog-to-digital (A/D) converters that allow isolated signal measurements and high-speed analog comparators for fast protection. Innovative software tools help power designers understand how to develop the closed-loop control functions of a digitally controlled SMPS system, simplifying the transition from traditional analog control methods.

To read the full white paper on high voltage, click here.



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