Supercapacitor IC provides uninterrupted power, protection and monitoring
Analog Devices announces the Power by Linear LTC3351, a supercapacitor charger and back-up power controller IC that includes hot swap front-end protection and the features necessary to provide standalone, capacitor-based back-up power.
The LTC3351’s integrated hot swap controller and circuit breaker uses n-channel MOSFETS to provide a low loss power path from the input to the output, plus foldback current limiting to reduce inrush current. The device enables reliable short term uninterrupted power in the event of a main power failure for applications such as solid-state drives (SSDs) and non-volatile dual in-line memory modules (NVDIMMs) data backup, power fail alarms in medical and industrial applications and “dying gasp” power fail indicators.
The LTC3351 provides PowerPath control, capacitor stack charging and balancing, protection and capacitor health monitoring. Other applications include high current 12V ride-through supplies and short term uninterruptible power supplies (UPS) for servers, mass storage and high availability systems.
The LTC3351 features a 4.5 to 35V input voltage range and over 10A of charge/backup current capability. The device also provides balancing and over-voltage protection for a series stack of one to four supercapacitors. The LTC3351’s synchronous step-down controller enables constant current/constant voltage charging of the capacitor stack at up to 5V per cell, adds Analog Devices. In back-up mode, the step-down converter runs in reverse as a synchronous step-up DC/DC to deliver power from the supercapacitor stack to the system supply to be backed up. The hot swap controller provides programmable under-/over-voltage thresholds, PCIe-compatible start-up timing and a precision threshold /retry input.
The LTC3351 includes a16-bit ADC which continuously monitors input and output voltage and current. The internal measurement system monitors parameters associated with the back-up capacitors, including capacitor stack voltage, capacitance and stack equivalent series resistance (ESR) to ensure adequate energy storage and power delivery during backup. By monitoring the capacitance of the back-up supercapacitors, the LTC3351 provides longer capacitor life by enabling the system to set the capacitor voltage to a minimum value while ensuring the required back-up energy is maintained. All system parameters and fault status can be monitored via a two-wire I2C interface, and alarm levels can be set to alert the system to a sudden change in any of these measured parameters.
The LTC3351 is available in a thermally enhanced 44-lead, low profile (0.75mm) 4.0 x 7.0mm QFN package. The device operates over a -40 to 125 degree C junction temperature range and is available from stock.