Evolution has been good for PMUs

The primordial human urge is to advance, to make things better, faster and bigger. We see the same human tendency repeated in the semiconductor industry, well, with the exception of bigger, which is actually smaller in the electronics world.  Once the transistor was invented, early pioneers asked, “Can we put more than one on the same chip?” leading to Jack Kilby’s invention of the integrated circuit.  And today, better, SMALLER and faster is alive and well with power management units (PMUs) integrating an astounding amount of circuitry into a single IC.

Single-output power devices, such as switcher-mode power supplies and low-drop out converters are essential in any electronic system. But nearly all power systems need multiple power sources. A PMU contains a variety of single-output solutions selected from a smorgasbord of power options. The PMU, as the cartoon illustrates, is like having multiple IC’s inside an IC.

Evolution of the PMU

PMU’s are as simple as just two LDO’s or switchers on a chip, or complex to include twenty-one outputs. PMU’s can be general-purpose, like a Swiss army knife, or can be designed with a specific application in mind.  For example, SSDs need power at certain voltages and current levels, and also need features like small footprint (larger mobile devices, anyone?) and light-load efficiency (when your device is in a low-power state, it draws as little power as possible). In this case, TI offers the LM10502 designed specifically for SSDs.

For those of you that design multiple-load systems, the simplicity and elegance of a PMU eases a complex design. But designing with a PMU is not trivial—you still need to configure the multiple channels, design the external components, ensure each channel is stable and efficiency is acceptable, and make sure the overall system performance heat generation is within spec.  Here is where I and my colleagues have been working hard over the last year—to incorporate PMUs into TI’s design tool.  The new WEBENCH® PMU Power Architect allows you to create complex designs incorporating PMUs and includes all the familiar WEBENCH features such as the optimizer dial, PDF report generation, operating value charts and performance charts. Take it for a spin:

From the TI PMU website, select your favorite PMU, such as the LM10502. In the WEBENCH panel, enter the requirements for your application, such as input voltage of 4.5V to 5V for the PMU, output voltage/current for three channels:  0.85V at 1A; 2.5V at 1A; and 3V at 10mA.

 Designing PMUs using the WEBENCH PMU power architect

  • Click “Open Design”
  • Optimize for cost, size and efficiency
  • Select from a range of analysis
  • Print the PDF report

For you visual folks, my colleague Wanda demonstrates the process in a video here.

Designing with PMUs using WEBENCH is easy—if not, please let me know!  And please share your experience here. I would love to hear from you.

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For more power management solutions, visit the Power House blog.