Smart Power Stage adds Flexibility to Vertical Power Delivery

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Integration is a key concern to any electronics designer, not just those in the power market. There are lots of benefits of adding functionality to a product, including getting designs to market quicker, cutting the bill of materials, and having more compact designs. As with any other design decision, there are also usually trade-offs, and for highly integrated products, this usually means giving up on the flexibility to get the exact circuit specifications that you need, and often a higher cost per device.

Manufacturers of power components have really taken to the integration trend, and currently offer a wide variety of options to designers, from discrete components to modules with the entire conversion circuit included in a single package. Integration in the power industry normally starts with the controller and then incorporates extra features. In practice, this meant incorporating the switching circuit with the controller in a monolithic package. Later, the inductor was added to the mix, and finally, modules were made available with passive components also integrated. That wide variety of choice allows designers to make the trade-offs that suit their unique application, for example, they could choose to use an IC that includes the controller, driver and switches, and tailor the remainder of the circuit using their desired passive components.

Analog Devices has now added to that list of choices with the launch of the MAX20845B smart power stage. Bucking the norm of the controller forming the basis of the IC, the company has taken it out completely, and integrated the high- and low-side drivers and switches in a single, compact package. This area of the circuit is possibly the most difficult part of the design to get correct, as there are many small issues that can affect the end performance if overlooked. The smart power stage optimizes the layout of the components to ensure better control, higher efficiency and lower losses. It also allows the designer a greater degree of freedom to pick the stand-alone controller that best suits the circuit and then customize the design with passive choices. The devices also incorporate sensors that enable phase current and temperature reporting, and fault-protection for a variety of faults.

Frederik Dostal, Subject Matter Expert for Power Management at Analog Devices explains, “Each smart power stage device has an electrical current rating of 70 amps, so a lot of power is flowing into the high side switch. It communicates the exact current and temperature back to the controller to decide if current needs to be moved to another power stage for better thermal balance. In its typical application in data centres, space is at a premium, so small Vcc and Vdd capacitors are integrated, which saves a lot of space, as these designs can have six or eight different phases, and placing the power stages next to each other with inductors and power stage components does not leave a lot of space available under the processor”.

Multiple MAX20845B smart power stage ICs can be combined with a single controllers to implement a high-density synchronous buck converter design. The switching frequency can be selected depending on the application and if the reduction of switching losses or conduction losses is more important. The high level of integration combined with advanced packaging ensures that the devices has low losses, even at higher frequencies. Fault-protection is included for overtemperature, VX short, I/O open/short, supply undervoltage lockout, and main power-supply overvoltage lockout, and an internal LDO is also available to simplify bias generation for applications that do not have 1.8V available.

https://www.analog.com/en/products/max20845b.html