1 Features
1• Charge Super Capacitor Pack From 2.1 V to 26 V
• CC/CV Charge Profile From 0 V Without
Precharge
• 600-kHz NMOS-NMOS Synchronous Buck
Controller
• Over 90% Efficiency for up to 10-A Charge
Current switched•
5-V to 28-V VCC Input Voltage Range
• Accuracy
– ±0.5% Charge Voltage Regulation
– ±3% Charge Current Regulation
• High Integration
– Internal Loop Compensation
– Internal Digital Soft Start
• Safety
– Input Overvoltage Protection
– Capacitor Temperature Sensing Hot and Cold
Charge Suspend
– Thermal Shutdown
• Status Outputs
– Adapter Present
– Charger Operation Status
• Charge Enable Pin
• 30-ns Driver Dead Time and 99.5% Maximum
Effective Duty Cycle
• Automatic Sleep Mode for Low Power
Consumption
– <15-μA Off-State Super Capacitor Discharge
Current
– <1.5-mA Off-State Input Quiescent Current

2 Applications
• Memory Backup Systems
• Industrial UPS Systems and Power Transient
Buffering
• Bridge Power to Buffer the Battery

3 Description
The bq24640 device is a highly integrated switched•
mode super capacitor charge controller. The device
offers a constant-frequency synchronous PWM
controller with high accuracy charge current, voltage
regulation, and charge status monitoring.
The bq24640 charges a super capacitor in two
phases: constant current and constant voltage
(CC/CV). The device can charge super capacitors
from 0 V with current set on the ISET pin. When the
super capacitor voltage reaches the programmed
target voltage, charge current begins tapering down.
The bq24640 enters a low-current sleep mode
(<15 μA) when the input voltage falls below the
output capacitor voltage.
The bq24640 has an input CE pin to enable and
disable charge, and the STAT and PG output pins
report charge and adapter status. The TS pin on the bq24640 monitors the temperature of the capacitor
and suspends charge during hot and cold conditions.