It seemed there was a theme this month: how to deal with power in embedded environments. Here’s a look at three approaches to different parts of the power challenge.

Measuring USB power

One of the major benefits of USB is its ability to power a connected device from the host port. USB 3.0 has done a couple of things to improve this capability by increasing the device unit load from 100 mA to 150 mA using a nominal 5 V and offering mandatory power management mechanisms such as inactivity timers and device-initiated power requests. A single USB 3.0 port now drives six unit loads. The question is: How can designers get the most, or more accurately, the least, out of this new power capability?

Figure 1: (click graphic to zoom by 1.2x)

To answer that, what would be useful is a USB protocol analyzer that could also measure power consumption, and that’s exactly what LeCroy has created. While the Voyager analyzer looks at USB 2.0 or 3.0 data traffic, its optional integrated Power Tracker feature simultaneously measures and plots voltage and current draw. Measurements are correlated so that designers can see power draw during different states of the protocol and make the right choices to save power.

LeCroy Corporation
www.lecroy.com
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Controlling power supplies

Many types of power supplies are digitally controllable and able to be monitored over an I2C bus using the PMBus protocol. If you’ve got an I2C port handy and know how to use it, great, but let’s say you’ve got something higher level like a USB port, RS-485 port, or CANbus connection.

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Emerson Network Power has designed three new simple extension cards to enable USB, CANbus, and RS-485 connectivity for the iMP and iVS AC-DC power supply families. These extension adapters provide the interface between the power supply control port (CaseRx/CaseTx) and the selected connectivity port, and program with a simple command set. This allows the energy-efficient iMP and iVS power supplies to be used in many industrial-type applications that rely solely on CANbus or newer installations that can use USB.

Emerson Network Power
www.powerconversion.com
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Staying powered through it all

The idea of an Uninterruptible Power Supply (UPS) isn’t anything new, but many UPS devices don’t go where they’re needed in embedded applications due to harsh environments. Companies have been ruggedizing industrial PCs for some time now, but what about the UPS?

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To help avoid power supply interruptions and voltage sags or spikes, noax Technologies has brought industrial packaging to the UPS. The company claims up to one hour of backup power using an integrated lead-gel accumulator, and the UPS operates from -20 °C to +50 °C. Software enables programmable shutdown sequence time and allows the battery to be changed without affecting the operation of connected computers. The UPS also offers selectable output of either 12 V or 24 V and has protection against input voltage reversal, output shorts, and unexpected battery discharge.

noax Technologies
www.industrial-panel-computer.com
RSC# 42703