The LTC3643EUDDPBF from Linear Technology efficiently charges a capacitor array up to 40 V from an input supply between 3 V to 17 V. When the input supply falls below the programmable power-fail threshold, the step-up charger operates in reverse as a synchronous step-down regulator to power the system rail from the backup capacitor during this power interruption/failure condition. When charging the backup capacitor, an external low value sense resistor may be used to maintain an accurate current limit from the input supply or implement PowerPath™ functionality. The step-down converter operates at a 1 MHz switching frequency, allowing small external components to be used. Low quiescent current during regulation maximizes the energy usage from the backup capacitor.
Feature
- Bidirectional Synchronous Boost Capacitor Charger/Buck Regulator for System Backup
- Wide Input Voltage Range: 3V to 17V
- Up to 40V Capacitor Voltage Storage for High Energy Backup
- 2A Maximum CAP Charge Current
- Integrated Power N-Channel MOSFETs (150mΩ Top and 75mΩ Bottom)
- Integrated Power N-Channel MOSFET for Output/CAP Disconnect (50mΩ)
- Input Current Limit During Charging
- Fast 1MHz Switching Frequency
- ±1% Reference Accuracy for System Voltage Regulation
- Indicator Outputs for Charge Status and Input Power Fail
- Low Profile 24-lead 3mm × 5mm QFN Package
Applications
- Backup Capacitor Systems
- Power Failure Backup Systems
- Solid-State Drives
