Single inductor, multiple-output PMIC halves regulator size for the IoT

Single inductor, multiple-output PMIC halves regulator size for the IoT

New Products |
By Nick Flaherty

The MAX17270, MAX77278, MAX77640/MAX77641 and MAX77680/MAX77681 reduce the power-management footprint by up to 50 percent for space-constrained products such as wearables, hearables, sensors, smart-home automation hubs and IoT devices. The architecture increases overall system efficiency by nine percent compared, reducing heat dissipation, an important consideration for wearable products that make skin contact.

The SIMO control architecture in the PMICs allows a single inductor to serve as the critical energy-storage element for multiple, independent DC-rail outputs. This allows designers to reduce the number of bulky inductors in their designs, thereby improving efficiency, shrinking form factor and reducing heat dissipation. In addition, the low quiescent current of the PMICs plays an important role in extending battery life. With the intrinsic buck-boost operation of the PMICs, the power rails can operate over a battery’s entire range.

The MAX17270 SIMO buck-boost converter is half the size of the previous SIMO-only devices, reducing the number of inductors and ICs that are required for a power tree. The quiescent current of 850nA for one SIMO channel and 1.3µA for three SIMO channels helps extend battery life of end devices, prevents overheating and reduces frequent charging cycles for wearables and hearables. They are available in TQFN and WLP package options. 

The MAX77278 is optimised for small lithium ion batteries with three buck-boost regulators with independent voltage outputs (0.8VOUT to 5.25VOUT), 16µA operating quiescent current/300nA standby current and flexible power sequencing. The device is also a charger for small Li+ cells (7.5mA – 300mA CC range), including an adjustable 425mA current sink for an LED, eight general-purpose input/output (GPIO) pins and a 3.7125V to 5.3V, 50mA low-noise low-dropout regulator (LDO) with fixed headroom control in a total footprint of 24mm². An I²C interface allows an applications processor to monitor the status and control power management in remote controls, health and fitness monitors, body cameras and IoT applications.

The MAX77640/MAX77641 also have three buck-boost regulators alongside a low-noise 150mA LDO, a GPIO output port, a triple current sink for an RGB LED array and flexible power sequencing. Operating current is just 5.6µA and shutdown current is 300nA. Available in a 16mm² total solution size, the MAX77640 and MAX77641 are ideal for applications with a built-in charger in areas like wearables, fitness and health monitoring and IoT.

The MAX77680/MAX77681 again have three buck-boost regulators, this time with a 3.0µA operating quiescent current, 300nA shutdown current and flexible power sequencing for smaller systems such as hearables (Bluetooth headsets/earbuds) and rings, watches and e-pens as the total footprint is 15.5mm². 

“As small, connected mobile devices become more sophisticated, they also require more power rails,” said Kevin Anderson, senior analyst, Power IC Research at IHS Markit. “Any technology that allows designers to add functionality, reduce form factor and improve power management simultaneously will find interest among developers who need to shrink the design footprint of their devices to make them more attractive to end users.” 

“The challenge facing developers is how to include the processor, high-quality audio, near-field communication, wireless connectivity and multiple sensors in wearable form factors that conserve precious battery life and manage the thermals, given that these devices often come in contact with heat-sensitive skin,” said Karthi Gopalan, director of business management, Mobile Power Business Unit, Maxim Integrated. “These SIMO PMICs continue our tradition of providing one-stop power management solutions for a wide range of next-generation, low-power designs.” 

The MAX17270 is available for $1.84 (1000-up, FOB USA); the MAX77278 is available for $2.18 (1000-up, FOB USA); the MAX77680 and MAX77681 are available for $1.24 (1000-up, FOB USA); and the MAX77640 and MAX77641 are available for $1.71 (1000-up, FOB USA) at Maxim’s website. The ICs are also available from select authorized distributors.

The MAX17270EVKIT# evaluation kit is available for $100; the MAX77278EVKIT# evaluation kit is available for $100; the MAX77680/MAX77681EVKIT# evaluation kit is available for $100; and the MAX77640/MAX77641EVKIT# is available for $100.

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