Powering efficiency

At the chip level, power consumption is everything. Those designing for consumer applications are pushing their products to the smallest possible process geometry in order to reduce the amount of power consumed, with the aim of extending battery operating life in portable products. At the product level, designers are being constrained by ever smaller device sizes. But these designs often have challenging power requirements and the engineer has to produce multiple operating voltages while bearing in mind thermal considerations. Meanwhile, there are still products which plug into the wall. Often, these devices are ‘always on’. Technology is now being applied to ensure their consumption is monitored and the device can ‘wake up’ quickly when activated. Vishay is one of the companies addressing power supply issues at the product level. It has introduced a reference design for a 200W 1/16th brick power supply. Claiming the announcement as an ‘industry first’, Vishay says the design has the highest power density and lowest component count of any such dc/dc power supply implementation currently available. The reference design (www.vishay.com/ppg?62932) delivers a power density in excess of 600W/in2, which Vishay says is more than 60% higher than any previous 1/16th brick design. Featuring a nominal 12V dc output, the design operates with 95% efficiency and 40% lower power losses at 270kHz. A fixed duty cycle mode provides a constant input-output voltage relationship to maximise efficiency. Meanwhile, an ENABLE pin is provided to allow the module to be turned on and off for use in power supply sequencing applications. According to Vishay, the design has been developed in order to help designers speed time to market. A further benefit is a large reduction in the space required for the brick. A quick look at the bill of materials shows that 90% of the components needed for the design can be obtained from Vishay, including the controller ic, power mosfets, the rectifier and additional passive components.