ROHM’s New 80V Withstand, 5A Output Power Supply ICs

Contributing to improved reliability and functionality in industrial equipment

ROHM’s new buck DC/DC converter ICs are ideal for applications supporting high voltages and currents in factory automation equipment

ROHM’s new buck DC/DC converter ICs are ideal for applications supporting high voltages and currents in factory automation equipment

Evaluation Boards are available now for the BD9G500EFJ-LA (7V to 76V input / 5A output, 1ch buck DC/DC converter with built-in high-side MOSFET, asynchronous rectification type) and the BD9F500QUZ (4.5V to 36V input / 5A output, 1ch buck DC/DC converter with built-in MOSFET, synchronous rectification type).

Evaluation Boards are available now for the BD9G500EFJ-LA (7V to 76V input / 5A output, 1ch buck DC/DC converter with built-in high-side MOSFET, asynchronous rectification type) and the BD9F500QUZ (4.5V to 36V input / 5A output, 1ch buck DC/DC converter with built-in MOSFET, synchronous rectification type).

Santa Clara, CA and Kyoto, Japan, June 30, 2021 (GLOBE NEWSWIRE) — ROHM Semiconductor today announced two new buck DC/DC converter ICs with built-in MOSFET – the BD9G500EFJ-LA and BD9F500QUZ – ideal for applications supporting high voltages and currents in factory automation equipment (e.g., PLCs / inverters, and 5G base stations that handle high power).

Recent years have seen evolving markets of battery-driven applications and advanced industrial equipment, such as 5G base stations and factory automation systems equipped with new functions utilizing AI and IoT. This demands power supply ICs that are not only compact and operate at high efficiency, but that also deliver large currents for operating multiple functions that can withstand high voltages to prevent damage from sudden surges (i.e., due to lighting).

The BD9G500EFJ-LA and BD9F500QUZ are non-isolated DC/DC converter ICs developed by utilizing proprietary analog design technology based on high-voltage BiCDMOS power processes to provide the power supply functionality required by increasingly sophisticated industrial equipment.

In addition to a best-in-class 80V withstand voltage for 48V power supply systems, the BD9G500EFJ-LA with built-in MOSFET delivers the largest output current in its class (5A), contributing to higher reliability and functionality in charging and 5G base stations that handle high power. At the same time, the BD9F500QUZ with built-in Nano Pulse Control™ technology achieving a high step-down ratio provides 39V withstand voltage and 5A output current in a compact, low-profile package (3.0×3.0×0.4mm). Moreover, the product features overcurrent protection, as SEL1/SEL2 pins can be selected. These features are ideal for 24V power supply systems – enabling support for higher functionality and greater miniaturization in a wide range of advanced industrial equipment (i.e., factory automation).

New DC/DC Converter IC Specifications

Part No.: BD9G500EFJ-LAWithstand Voltage (V) (max.): 80Input Voltage Range (V): 7 to 76Output Voltage Range (V): 1 to 0.97 × VINOutput Current (A) (max.): 5Switching Frequency (MHz): 0.1 to 0.65Operating Temp. Range (°C): -40 to +125Package (mm): HTSOP-J8 (4.9×6.0×1.0)

Part No.: BD9F500QUZWithstand Voltage (V) (max.): 39Input Voltage Range (V): 4.5 to 36Output Voltage Range (V): 0.6 to 14Output Current (A) (max.): 5Switching Frequency (MHz): 0.6, 1.0, 2.2Operating Temp. Range (°C): -40 to +85Package (mm): VMMP16LZ3030 (3.0×3.0×0.4)


A person’s interaction with the outside world occurs through information being received and sent: input and output. In an interaction with a computer the user receives information that is output by the computer, and responds by providing input to the computer – the user’s output becomes the computer’s input and vice versa. Consequently the use of the terms input and output may lead to confusion so we shall blur the distinction somewhat and concentrate on the channels involved. This blurring is appropriate since, although a particular channel may have a primary role as input or output in the interaction, it is more than likely that it is also used in the other role. For example, sight may be used primarily in receiving information from the computer, but it can also be used to provide information to the computer, for example by fixating on a particular screen point when using an eyegaze system.

Input in the human occurs mainly through the senses and output through the motor control of the effectors. There are five major senses: sight, hearing, touch, taste and smell. Of these, the first three are the most important to HCI. Taste and smell do not currently play a significant role in HCI, and it is not clear whether they could be exploited at all in general computer systems, although they could have a role to play in more specialized systems (smells to give warning of malfunction, for example) or in augmented reality systems. However, vision, hearing and touch are central.

Similarly there are a number of effectors, including the limbs, fingers, eyes, head and vocal system. In the interaction with the computer, the fingers play the primary role, through typing or mouse control, with some use of voice, and eye, head and body position.

Imagine using a personal computer (PC) with a mouse and a keyboard. The appli- cation you are using has a graphical interface, with menus, icons and windows. In your interaction with this system you receive information primarily by sight, from what appears on the screen. However, you may also receive information by ear: for example, the computer may ‘beep’ at you if you make a mistake or to draw attention to something, or there may be a voice commentary in a multimedia presentation. Touch plays a part too in that you will feel the keys moving (also hearing the ‘click’) or the orientation of the mouse, which provides vital feedback about what you have done. You yourself send information to the computer using your hands, either by hitting keys or moving the mouse. Sight and hearing do not play a direct role in sending information in this example, although they may be used to receive

information from a third source (for example, a book, or the words of another per- son) which is then transmitted to the computer.

In this section we will look at the main elements of such an interaction, first con- sidering the role and limitations of the three primary senses and going on to consider motor control.

1.2. Vision

Human vision is a highly complex activity with a range of physical and perceptual limitations, yet it is the primary source of information for the average person. We can roughly divide visual perception into two stages: the physical reception of the stimulus from the outside world, and the processing and interpretation of that stimulus. On the one hand the physical properties of the eye and the visual system mean that there are certain things that cannot be seen by the human; on the other the interpretative capabilities of visual processing allow images to be constructed from incomplete information. We need to understand both stages as both influence what can and cannot be perceived visually by a human being, which in turn directly affects the way that we design computer systems. We will begin by looking at the eye as a physical receptor, and then go on to consider the processing involved in basic vision.

1.3. The human eye

Vision begins with light. The eye is a mechanism for receiving light and transform- ing it into electrical energy. Light is reflected from objects in the world and their image is focussed upside down on the back of the eye. The receptors in the eye transform it into electrical signals which are passed to the brain.

The eye has a number of important components (see Figure 1.1) which we will look at in more detail. The cornea and lens at the front of the eye focus the light into a sharp image on the back of the eye, the retina. The retina is light sensitive and con- tains two types of photoreceptor: rods and cones.

Rods are highly sensitive to light and therefore allow us to see under a low level of illumination. However, they are unable to resolve fine detail and are subject to light saturation. This is the reason for the temporary blindness we get when moving from a darkened room into sunlight: the rods have been active and are saturated by the sudden light. The cones do not operate either as they are suppressed by the rods. We are therefore temporarily unable to see at all. There are approximately 120 million rods per eye which are mainly situated towards the edges of the retina. Rods there- fore dominate peripheral vision.

Cones are the second type of receptor in the eye. They are less sensitive to light than the rods and can therefore tolerate more light. There are three types of cone, each sensitive to a different wavelength of light. This allows color vision. The eye has approximately 6 million cones, mainly concentrated on the fovea, a small area of the retina on which images are fixated.

THEORY AND Human Computer Interaction


Major theories Concept Map based on main research areas

Unfortunately for us, there is no general and unified theory of HCI that we can present. Indeed, it may be impossible ever to derive one; it is certainly out of our reach today. However, there is an underlying principle that forms the basis of our own views on HCI, and it is captured in our claim that people use computers to accomplish work. This outlines the three major issues of concern: the people, the computers and the tasks that are performed. The system must support the user’s task, which gives us a fourth focus, usability: if the system forces the user to adopt an unacceptable mode of work then it is not usable.

There are, however, those who would dismiss our concentration on the task, saying that we do not even know enough about a theory of human tasks to support them in design. There is a good argument here (to which we return in Chapter 15). However, we can live with this confusion about what real tasks are because our understanding of tasks at the moment is sufficient to give us direction in design. The user’s current tasks are studied and then supported by computers, which can in turn affect the nature of the original task and cause it to evolve. To illustrate, word processing has made it easy to manipulate paragraphs and reorder documents, allowing writers a completely new freedom that has affected writing styles. No longer is it vital to plan and construct text in an ordered fashion, since free-flowing prose can easily be restructured at a later date. This evolution of task in turn affects the design of the ideal system. However, we see this evolution as providing a motivating force behind the system development cycle, rather than a refutation of the whole idea of supportive design.

This word ‘task’ or the focus on accomplishing ‘work’ is also problematic when we think of areas such as domestic appliances, consumer electronics and e-commerce. There are three ‘use’ words that must all be true for a product to be successful; it must be:

useful – accomplish what is required: play music, cook dinner, format a document; usable – do it easily and naturally, without danger of error, etc.;
used – make people want to use it, be attractive, engaging, fun, etc.

The last of these has not been a major factor until recently in HCI, but issues of motivation, enjoyment and experience are increasingly important. We are certainly even further from having a unified theory of experience than of task.

The question of whether HCI, or more importantly the design of interactive sys- tems and the user interface in particular, is a science or a craft discipline is an inter- esting one. Does it involve artistic skill and fortuitous insight or reasoned methodical science? Here we can draw an analogy with architecture. The most impressive struc- tures, the most beautiful buildings, the innovative and imaginative creations that provide aesthetic pleasure, all require inventive inspiration in design and a sense of artistry, and in this sense the discipline is a craft. However, these structures also have to be able to stand up to fulfill their purpose successfully, and to be able to do this the architect has to use science. So it is for HCI: beautiful and/or novel interfaces are artistically pleasing and capable of fulfilling the tasks required – a marriage of art and science into a successful whole. We want to reuse lessons learned from the past about how to achieve good results and avoid bad ones. For this we require both craft and science. Innovative ideas lead to more usable systems, but in order to maximize the potential benefit from the ideas, we need to understand not only that they work, but how and why they work. This scientific rationalization allows us to reuse related con- cepts in similar situations, in much the same way that architects can produce a bridge and know that it will stand, since it is based upon tried and tested principles.

The craft–science tension becomes even more difficult when we consider novel systems. Their increasing complexity means that our personal ideas of good and bad are no longer enough; for a complex system to be well designed we need to rely on something more than simply our intuition. Designers may be able to think about how one user would want to act, but how about groups? And what about new media? Our ideas of how best to share workloads or present video information are open to debate and question even in non-computing situations, and the incorporation of one version of good design into a computer system is quite likely to be unlike anyone else’s version. Different people work in different ways, whilst different media color the nature of the interaction; both can dramatically change the very nature of the original task. In order to assist designers, it is unrealistic to assume that they can rely on artistic skill and perfect insight to develop usable systems. Instead we have to pro- vide them with an understanding of the concepts involved, a scientific view of the reasons why certain things are successful whilst others are not, and then allow their creative nature to feed off this information: creative flow, underpinned with science; or maybe scientific method, accelerated by artistic insight. The truth is that HCI is required to be both a craft and a science in order to be successful.