A power supply manager introduced by Linear technology features EEPROM to digitally manage power supply systems with four or more power rails.
The LTC2974 utilises an I²C interface and PMBus command set to monitor and control positive or negative supplies. The device provides rapid troubleshooting and debug capabilities during power system design, development, production and failure analysis. Any supply with a ‘run’ pin can be sequenced and controlled using tracking or time-based events.
The solution has four channels that simultaneously monitor voltage and current, as well as external temperature so users can compensate for shifting MOSFET RDS(ON) or inductor DCR. Each supply can be margined and trimmed over temperature, using a digital servo loop that measures the rail voltage and continuously adjusts to maintain accuracy. All of the supply functions perform with accuracy, with more than ±0.25 percent total unadjusted error.
Users can utilise the onboard GUI to intuitively configure and interrogate the registers, user settings, and fault log. For applications requiring more than four supplies, the device can be cascaded using a 1-wire synchronisation bus, allowing fault dependencies to be established across devices sharing the fault bus.
The power supply manager is suitable for a wide variety of applications, including uninterruptible power supplies (UPS), automotive, medical, video and networking applications. The device integrates key building blocks, such as differential measurement and adjustment, high resolution data converters, high retention EEPROM, and a precise reference to enable digital management of an otherwise purely analogue power system. A programmable watchdog timer provides supervision to an external microcontroller, FPGA, ASIC. All four channels are fully functional, with dedicated monitoring, supervising, sequencing, margining, trimming, fault protection features. Black box fault logging provides a method to diagnose failure at the time of fault by storing critical parameters in EEPROM. In the field, it operates autonomously to provide continuous supervision and to take preprogrammed action in response to faults. The device is also protected with an internal die temperature sensor. This high level of mixed-signal integration ensures that the LTC2974 can reliably manage even the most complex power supply systems with ease.
Linear Technology
