ST Praises Power Management IC for Saving Board Space, BOM, & Power
ST’s STPMIC1 is both a general-purpose system power management device and a companion chip for the STM32MP1 microprocessor.
STMicroelectronics' new power management IC (PMIC) packs six low-dropout regulators, four DC/DC buck converters, and one boost DC/DC converter into a 5mm x 6mm x 0.8mm WFQFN package.
Block diagram of STPMIC1. Image from STMicroelectronics
ST claims that the device not only cuts down on the parts required to provide multiple power rails; it also affords monitoring and protection for each of them.
Optimized for ST's STM32MP1 MPU
The PMIC is optimized for ST's microprocessor STM32MP1—which is part of a series for IoT and industrial applications.
As such, the PMIC adheres to the accuracy and settling-time requirements of its host MPU.
Diagram of how STPMIC1 and STM32P1 function together. Image from STMicroelectronics
The STPMIC1 is controlled from the host processor through an I²C and IO interface. Users can scale using programmable non-volatile memory, which is said to offer support for a range of applications.
The unit is intended to power external memory and peripherals as well as its host MPU. It can also work with input voltages ranging from 2.8V to 5.5V.
Four Buck Converters, Six LDO Channels, One Boost Converter
The STPMIC1’s four buck converters are built to provide a fast, transient response and precise output-voltage control. This will allow it to handle a number of operating conditions.
The device achieves up to 90% efficiency through a low-power PFM mode with a smooth transition to PWM during normal operations.
The STPMIC1. Image from STMicroelectronics
EMI is minimized through a PWM synchronization technique employing an integrated phase lock loop.
One of the six LDO (low-dropout) regulators features automatic power source detection, making it suitable to power a USB PHY.
Another LDO regulator is designed for DDR3 termination and for low-power DDR, which can operate in bypass mode. The other four LDOs are for general purposes.
The single boost converter, also featuring bypass-mode capability, can power three USB ports.
STMicroelectronics states that the converter achieves smooth regulation when operating from a battery or even from a consumer-grade 5V AC/DC source.
Boost converter for USB-VBUS. Image from Image from STMicroelectronics
The PMIC features two power switches for USB sub-systems. One is a 500mA power switch with input internally connected to boost.
It is compatible with a USB Type-C DRD or USB OTG port and it supports VBUS detection, OCP, and reverse current protection. The other, supplying up to 1A, can support two USB STD HOST ports.
Applications Beyond ST's MPU
The STPMIC1, while optimized to serve as the power management chip for ST’s STM32MP1 MPU, is also compatible for:
- Power management for other embedded MPUs
- Smart home applications
- IoT edge point devices
- Wearable and portable devices
- Man-machine interfaces
STPMIC1 for industrial applications. Image from STMicroelectronics
ST has explained that other key applications they see for the PMIC include industrial applications (for example, controls, POS, M2M interfaces, and predictive
maintenance), home automation, networking, and medical monitoring.
Evaluation Board for PMIC Prototyping
The STEVAL-PMIC1K1 is an evaluation board for the STPMIC1 that is designed to simplify the PMIC’s prototyping. A USB dongle is included, through which I²C access to the STPMIC1’s configuration registers is established.
The STEVAL-PMIC1K1 Evaluation board. Image from STMicroelectronics
Users can trigger the PMIC’s features through digital I/O’s and pushbuttons, making STEVAL-PMIC1K1 an easy-to-use option.
Around the Industry
PMICs are a great way to lower the BOM count. They can simplify manufacturing and conserve precious board space. It’s no surprise, then, that there are many entrants in this race, serving a diversity of product segments.
Renesas’s ISL95906 is a PMIC aimed at notebook and tablet computers. It features VDDQ and VTT regulators for memory types DDR3/L/U, LPDDR3, and DDR4.
NXP’s FS5502, like the STPMIC1, is designed specifically for one MPU—in this case, NXP’s S32Rx. This device is focused on radar applications. Various versions are available with different output voltages, switching frequencies, and power-up sequencing.
