[FAQ] TPS65219: Benefits of a PMIC vs discrete solution to power Sitara AM62x MPU

As systems continue to shrink in both size and power usage, while growing in functionality, designers face the challenge of how to effectively power embedded processor systems. Embedded processor systems require a power solution that can be implemented quickly and optimize board space. One option for creating the power tree is to use an individual power regulator integrated circuit (IC) for each rail of the processor, FPGA, or SoC. This is commonly referred to as a discrete solution. The other option is to use a multichannel power management IC, or PMIC.

More advanced power solutions such as in EV charging, HMI, and HVAC controllers require high-performance power solutions with features such as power sequencing, low-power modes and monitoring elements. PMICs unify many common power-management functions into a single energy-efficient chip, which can simplify designs, shrink power solution sizes, and optimize processor performance. This application report compares two Sitara AM62 Starter Kit EVM power solutions and outlines the benefits of using a highly integrated TPS65219 PMIC versus a discrete regulator approach.

Solution size

TPS65219 is a high power-density PMIC which integrates 3 bucks and 4 LDOs in a small 5mm x 5mm2 or 4mm x 4mm package. The TPS65219 PMIC is able to provide up to 60% power solution size savings compared to the discrete solution for powering AM62. The six discrete power ICs used in a discrete solution implementation can be replaced by a single TPS65219 chip. TPS65219 further shrinks the overall BOM size when considering the passive components in each solution. The high 2.3Mhz switching frequency of TPS65219 allows fewer and smaller size inductors and output capacitors. AM62x Starter Kit EVM with PMIC is available here: SK-AM62B-P1

Below table provides a comparison of PMIC vs discrete solution size and component count based on varying AM62x use cases of Vdd_core operation. TPS65219 PMIC leverages integration to simplify the total BOM reducing the total solution size of parts to 37.98 mm2 for the 5mm x 5mm and 46.98 mm2 for the 4mm x 4mm. In addition, a PMIC solution decreased the number of total BOM components from 51 to 27.

Greater level of system control, safety and flexibility

AM62 requires controlled power-up and power-down sequences to properly operate subsystems and downstream components. Power sequencing is critical in voltage rails that must turn on in specific orders to ensure operational safely and reliability. Sequencing the rails also helps stagger the inrush current during power-up, which reduces system stress and prevents unexpected reverse bias conditions.

TPS65219 PMIC simplifies the BOM with built-in voltage supervisors and a digital sequencer integrated within the PMIC. Meanwhile the discrete SK-AM62 solution requires 6 additional components to enable a daisy-chain sequence, which does not have the same level of control and precision as the TPS65219’s sequencer capabilities. The TPS65219 sequencer has a built-in memory that allows digitally controlled sequencing and information that can be read back to the processor through I2C. The advantages of the TPS65219 digital power sequencer in comparison to a discrete implementation is:

• Reduced external component count and smaller footprint.
• Greater precision and customization of the sequence.
• Flexibility to include sequencing for additional peripherals or discrete devices in the system. Power up and down sequence can also be reprogrammed through I2C.
• Supervisory functions such as over and under voltage, fault flags, and safe state transitions.

Linux driver benefits

TPS65219 can enable power savings and optimize the performance of the AM62 through PMIC specific Linux driver available that have been pushed upstream to the Linux kernel at kernel.org. These certified and tested drivers have already been integrated to the AM62 SK, and provide Impressive control over details such as power rail voltages and power sequencing. Linux® drivers developed specifically for these PMICs enable the system to trigger reboots, soft restarts and low-power modes; they also enable dynamic voltage scaling, adapting buck-converter voltages to match the system’s current power needs.

PMIC Driver Features

• U-Boot1 Linux (loads to MPU)
• I2C Drivers
• Regulator Control (V, mode)
• SD card select and voltage control
• Low power mode "STBY“
• Dynamic voltage scaling
• SW shutdown
• PB Startup and shutdown
• Reset
• Interrupt interrogation and service
• GPIO Control
• Upstream drivers in Uboot and Kernel (Linux) with HW updates in repositories
• Automated tests2 for kernel and Uboot

Accelerate your time to market

TPS65219 was co-developed with AM62 to meet all power specifications and optimize the performance of the processor and its principal peripherals such as microSD card and LPDDR4/DDR4 memory. TPS65219 is available in several factory programmed configurations to power multiple AM62 use-cases. Learn more about these configurations in “Powering the AM62x with the TPS65219 PMIC” application note.    

Summary

Utilizing a PMIC can reduce system size and layout versus discrete power designs as well as provide other on chip monitoring and diagnostics. TPS65219 PMIC can optimize solution size, allow a greater level of system control, safety and flexibility, while also accelerating time to market.