PMIC extends operating time for small portables

Rohm Semiconductor has announced the BD71837MWV programmable system power management integrated circuit (PMIC) which is optimised for NXP Semiconductors’ i.MX 8M application processors.

The i.MX 8M applications processors process audio, video, and graphics in a range of applications from home audio/video to industrial automation and mobile computing.

The BD71837MWV integrates all power rails required by i.MX 8M processors and system peripherals. The buck converter provides a maximum conversion efficiency of 95 per cent and most protection functions required by the system are included to reduce the development time, decrease size, and simplify system design, according to Rohm.

As the IoT evolves, electronic devices such as smart speakers interact with users through voice commands for streaming audio/video. NXP’s i.MX 8M family integrates up to four Arm Cortex-A53 and Cortex-4 cores, a range of memory options and a high-speed connectable user interface. There is also 4K Ultra HD and HDR video functionality, high-fidelity audio playback, up to 20 audio channels, and support for DSD512 audio.

The BD71837MWV’s power supply circuit is designed specifically for the power supply system of the i.MX 8M processor family. It integrates eight buck converters, seven LDOs, and control logic that allows it to supply power to the processor, and also the required DDR memory, from a single chip. A 1.8V/3.3V power switch for SDXC cards is also built in, together with a 32.768kHz crystal oscillator buffer and multiple protection circuits such as output short-circuit, output over-voltage/current, and thermal shutdown.

Buck conversion efficiency from 83 to 95 per cent is achieved for 0.7 to 3.3V output, and the 2.7 to 5.5V input range supports power sources, from batteries to USB.

Power sequencing, SoC-PMIC control signalling, and power state transitions are automatically handled by hardware control logic. The BD71837MWV supports all i.MX 8M low-power states such as SNVS and suspend, consuming only 30 microA in the SNVS state and 137 microA at idle with all but two power rails on. Communication with the host processor is performed via I2C, enabling 100/400kHz and 1MHz operation.

The compact 8.0 x 8.0mm 68-pin QFN package’s pin layout is designed to ensure easy connection to NXP’s i.MX 8M processor and DDR memory, reducing design load. Rohm reports that 56 fewer parts are needed compared with discrete solutions, reducing PCB area by up to 45 per cent. Two-sided mounting enables all power management functions with less than 400mm2 board size.

The BD71837MWV integrates a sequencer compatible with power modes supported by i.MX 8M processors (run, idle, suspend, SNVS, off). Power mode transition conditions, protection function enable/disable, and on/off control and voltage for each power supply can be customised through the I2C interface and one time programmable ROM for the memory type and functions required by the system.

A PMIC evaluation board is also available.

The BD71837MWV samples next month.

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