Linear Tech Octal PMBus Power Supply Monitor Manages DC-DC Converters Digitally
Linear Technology Corp. introduced the LTC2978 Power Supply Monitor and Controller for digital management of up to eight 0 to 6V power supplies. Configuring multiple dc-dc converters in an already complex system can be a complicated design task when using passive components.
Values defined by external trim resistors and capacitors such as startup time, setpoint value or switching frequency make a system inflexible. To help alleviate these issues, digital control over analog power supplies has allowed for quick adjustment of output voltages and precise protection, monitoring and diagnostic mechanisms.
The LTC2978’s PMBus® compliant interface provides easy access to an on-board EEPROM, giving users supply configuration, fault response and logging capabilities. In addition, an array of supervising, margining and sequencing functions are said to make the LTC2978 a convenient, all-in-one digital power management solution, drastically simplifying the design challenges and reducing the component count typical of traditional analog control.
The LTC2978 provides numerous functions with on-the-fly adjustments that make it an ideal device for digital power control in a wide variety of automotive, medical and telecommunication applications. An integrated 15-bit ADC and 9:1 ADC MUX allows the IC to accurately monitor and servo eight output channels and one input channel. The primary PMBus operations include sequencing the startup of supplies, adjusting point-of-load voltages using voltage-buffered 10-bit current output digital-to-analog converters (IDACs), margining voltages to programmed limits and supervising output voltages, as well as the LTC2978’s die temperature, for overvalue or undervalue conditions. The configuration settings of these operations are all user-programmable and can be stored in EEPROM along with any faults, allowing for discontinuous system use. A programmable watchdog timer is also provided to supervise an external microcontroller, FPGA or ASIC. For applications that monitor more than eight supplies, the LTC2978 can be cascaded using only two connections. This extremely high level of mixed-signal integration ensures that the LTC2978 can reliably manage even the most complicated power supply systems today with ease.
The LTC2978 is available in a 64-lead 9 x 9mm QFN package that is RoHS compliant, and is specified over the commercial and industrial temperature ranges. Pricing starts at $10.95 each in 1,000 piece quantities.
