13 Aug 2018
Efficient supercapacitor backup power management system unveiled
Analog Devices has announced the Power by Linear LTC4041, a complete supercapacitor backup power management system for 2.9V to 5.5V supply rails that must be kept active during a main power failure. Supercapacitors have higher power density than batteries, making them ideal for systems requiring high peak power backup for short periods of time.
The LTC4041 uses an on-chip bidirectional synchronous converter to provide high efficiency step-down supercapacitor charging, as well as high current, high efficiency boost backup power. When external power is available, the device operates as a step-down battery charger for one or two supercapacitor cells while giving preference to the system load. When the input supply drops below the adjustable power-fail input (PFI) threshold, the LTC4041 switches to step-up regulator operation, capable of delivering up to 2.5A to the system load from the supercapacitor. During a power fail event, the device’s PowerPath control provides reverse blocking and a seamless switchover from input power to backup power. Typical applications for the LTC4041 include ride-through “dying gasp” supplies, high current ride-through 3V-5V uninterruptible power supplies (UPSs), power meters, industrial alarms, servers and solid-state drives.
The LTC4041 includes an optional overvoltage protection (OVP) function using an external FET which can protect the IC from input voltages greater than 60V. An internal supercapacitor balancing circuit maintains equal voltages across each supercapacitor and limits the maximum voltage of each supercapacitor to a predetermined value. Its adjustable input current limit function enables operation from a current limited source while prioritizing system load current over battery charge current. An external disconnect switch isolates the primary input supply from the system during backup. The device also includes input current monitoring, an input power fail indicator, and a system power fail indicator.
The LTC4041 is offered in a low profile (0.75mm) 24-lead 4mm x 5mm QFN package with backside metal pad for excellent thermal performance. The device operates from –40°C to 125C, in both E and I grades.
Summary of Features: LTC4041
2.5A Step-Down Supercapacitor Charger & 2.5A Step-Up Backup Supply
6.5A Switches for 2.5A Backup from One Supercapacitor or Two in Series
Current Limit Prioritizes Load over Charge Current
Input Ideal Diode Isolates Input During Backup
Automatic Seamless Switchover to Backup Mode
Internal Supercapacitor Balancer (No External Resistors)
Programmable Charge Current & Charge Voltage
Input Power Fail Indicator
System Power Good Indicator
Optional OVP Circuitry Protects Device to >60V
Constant Frequency Operation
Thermally Enhanced 24-Lead 4mm × 5mm QFN Package
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