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.