Power management and the development of the USB field, are you worthy of attention?

In recent years, power management and USB are two that are undergoing rapid development. Since the manufacturer added the control chip required for USB to the ASIC (dedicated IC) of the peripheral device, the support of the USB by the PC only needs to increase the socket with a cost of less than one dollar. This greatly stimulated the development of USB. Microsoft’s PC98 and PC99 systems have announced that USB and HID will be one of the industry standards it supports. As a general-purpose device, power supply equipment is increasingly developing toward a unified standard. The realization of the USB standard in power supply equipment greatly improves the versatility of power supply equipment and simplifies the control and management of power supply equipment. It is conceivable that with the development of USB, US

In recent years, power management and USB are two that are undergoing rapid development. Since the manufacturer added the control chip required for USB to the ASIC (dedicated IC) of the peripheral device, the support of the USB by the PC only needs to increase the socket with a cost of less than one dollar. This greatly stimulated the development of USB. Microsoft’s PC98 and PC99 systems have announced that USB and HID will be one of the industry standards it supports. As a general-purpose device, power supply equipment is increasingly developing toward a unified standard. The realization of the USB standard in power supply equipment greatly improves the versatility of power supply equipment and simplifies the control and management of power supply equipment. It is conceivable that with the development of USB, USB-supported power devices will also become standard power devices, all of which will make power management more standard and easier.

Power source management has always been one of the main links in the design and maintenance of Electronic products. In the past, users wanted to understand the power supply, only through limited work instructions on the equipment; with the development of computer technology, the power supply system (such as UPS) began to communicate with the computer through RS-232, so that users can control the power supply greatly. Convenient; but RS-232 is not perfect either. The development of the bus structure has brought IEEE1394 (high-speed serial bus) and USB. The power supply finally chose the USB standard suitable for low- and medium-speed peripherals. This is not to follow the fashion, there is a deep demand background behind it.

It is one of the development trends of power supply equipment to follow the USB standard to design and manage power supply equipment, and fully realize the advantages of plug-and-play USB equipment, low power consumption and convenient use and maintenance.

1. USB universal serial bus and HID man-machine interface equipment

USB (Universal Serial Bus) is based on Intel, and is a serial interface standard jointly developed by seven companies including Compaq, Microsoft, IBM, DEC, Northern Telecom, and NEC of Japan. The first draft was formulated in November 1994 , The USB specification version 1.0 was announced in February 1996. USB can connect up to 127 peripherals to your system, and its 12Mbps bandwidth is completely sufficient for low and medium-speed peripherals such as keyboards and mice. This technology allows you to plug in or unplug the device from your system at any time, and eventually you will no longer need to set up multiple parallel and serial ports behind your PC.

USB divides devices into different types, and each device type defines the common behaviors and protocols of similar functional devices. HID (Human Interface Device) mainly refers to the device used for human to control the operation of the computer system, and the power device (Power Device) is positioned as one of the subsystems of HID. The purpose of classifying devices is to erase the differences between different hardware manufacturers, so that the host (PC) can conveniently and uniformly manage the devices. Devices of the same type are composed of a set of standard-defined functional modules. In this way, the communication between the host and the USB device can be completed through some standard format data packets.

2. HID power supply equipment

The power management of the equipment is usually through the internal hardware integration control component to complete the management of the battery or the internal power supply device. Similarly for external power supply equipment, (such as equipment powered by UPS), there are also special control components to complete various control functions. In either case, the communication of the status and control information between the host and the control component can be completed through the USB protocol, so that the host can achieve absolute control of the power supply of the device.

From the perspective of the host, since the USB power device protocol is designed in the framework of the USB human-machine interface device, the HID class driver on the host is the foundation for the realization of the power device. With the help of the HID class driver, the device driver can directly access the device on a much more friendly platform without too much consideration of the interaction between the class driver and the low-level software of the system.

In short, through a series of standard definitions, USB enables users to directly touch the power management of the device through the host, which greatly enhances and facilitates the power management function.

3. Object definition of power supply equipment

Each power supply device is composed of a set of modules (such as battery systems, power converters), and each module can be subdivided into one or more sub-modules. Sub-modules can exist inside the modules (such as batteries, chargers), or they can be interfaces between modules. All modules, submodules, and interfaces are defined as objects, with clear physical descriptions:

Battery

Charger

Input and Output

Battery System (a collection of battery, charger and input/output)

Power Supply or Power Converter (conversion and output of specific voltage and frequency)

Outlet and Outlet System (power outlet and power outlet system-power output that can be remotely switched on and off by a PC)

Gang (group-a collection of objects with the same characteristics and functions)

Flow (flow-a summary description of the electrical characteristics of the power cord)

Power Summary (power report), for the power supply device to provide its own work and status messages to the host or other devices, complete the power supply’s own information collection and external communication,

The structure of modules, small modules, and interfaces within different power supply devices is called the object hierarchy table of power supply devices, which are as follows:

1. Battery system:

Input (connect to input stream)

charger

Battery (connect to charger or output)

Output (connect to output stream)

2. Power converter:

Input (connect to output stream or output)

Output (connect to input stream or input)

3. Power outlet system:

Independent power outlet (connect to output stream)

An input stream

Output stream

Power report (connect to output stream)

The sub-modules inside the module are directly connected, while different modules are connected by flow, and the connection points are the input and output of the module.

4. The realization of two simple power equipment

1. Power supply for a typical USB peripheral

Power management and the development of the USB field, are you worthy of attention?

Figure 1. Power supply of a typical USB peripheral

One AC input stream, one DC input stream (USB bus power)

A power converter (including an AC input, a DC input and a DC output)

One DC output stream

A power report

2. A simple UPS power supply

One AC input stream (main AC input)

A battery system (one AC input, one battery, one charger and one DC output)

One DC stream (backup DC)

A power converter (one DC input, one AC input and one AC output)

One AC output stream (AC stream)

A power report

Figure 2. Simple UPS power supply

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