When you make a consumer electronic device smaller than a bread box but which consumes as much power as a refrigerator, you had better expect to get attention from energy efficiency regulators.
That is the situation makers of set-top cable TV boxes now find themselves in. Fortunately for them, there are a variety of ICs ready to help minimize power consumption on these devices as well as on a variety of other consumer electronics.
Recent developments in this class of ICs include the Energy$ense product family from Akros Silicon Inc. The firm's AS19xx chips are high efficiency triple output synchronous buck PMICs (Power Management ICs) targeting not just set-top boxes, but also eBooks, mobile platforms, residential gateways, automotive infotainment gear, and a variety of other uses. There is also a version for driving LEDs.
Their claim to fame is the ability to handle power management and monitoring functions in consumer electronics that formerly would have required numerous ICs. Output one on an AS19xx chip is, depending on the specific device, a buck, boost, or LED boost controller with FET drivers. Outputs two and three are 2-A buck regulators with integrated FETs.
The designs are about 93% efficient and include efficiency features such as light-load efficiency management and low standby and quiescent currents. Versions serving as LED drivers also can handle high-frequency PWM dimming.
With compact applications in mind, the chips use synchronous spread-spectrum clocking, modulating the clock frequency by a few percent, to keep down EMI without having to take up a lot of space with shielding.
Akros says many consumer devices could be powered by a combination of two of the chips. In one scenario for a set-top box, Akros figures an AS1943 and AS1923 could be ganged to produce 1.2, 3.3, 5, 1.8, 2.5, and 4.5-V power lines.
More info: http://www.akrossilicon.com/AS1933-43