DC1589A: SuperCap Charger with Current-Limited Ideal Diode and V/I Monitor

Summary

The DC1589A is a constant-current/constant-voltage linear charger circuit designed to charge a 2-cell supercap stack from either a Li-Ion/Polymer battery, a USB port, or a 2.7V to 5.5V current-limited supply. The part operates as an ideal diode with an extremely low 50mO on-resistance making it suitable for high peak-power/low average power applications.

The LTC4425 charges the output capacitors to an externally programmed output voltage in LDO mode at a constant charge current, or to VIN in normal mode with a smart charge current profile to limit the inrush current until the VIN to VOUT differential is less than 250mV. In addition the LTC4425 IC can be set to clamp the output voltage to 4.9V or 5.4V.

The Charge current (VOUT current limit) is programmed by connecting a resistor between PROG and GND. The voltage on the PROG pin represents the current flowing from VIN to VOUT for current monitoring. An internal active balancing circuit maintains equal voltages across each supercapacitor and clamps the peak voltage across each cell to a pin-selectable maximum value. The LTC4425 operates at a very low 20µA quiescent current (shutdown current <3µA)

Specifications

Manufacturer	Analog Devices Inc.
Category	Power Management
Sub-Category	Capacitor Chargers
Eval Board Part Number	505-DC1589A-ND
Eval Board Supplier	Analog Devices Inc.
Eval Board	Normally In Stock
Capacitor Type	Super Capacitor
Function	Charger Controller
Number of Capacitors	2
Voltage In	2.7 ~ 5.5 V
Voltage Out (Max)	5.4 V
Charge Current (Max)	2 A
Topology	Linear
Features	Adjustable Output Current Adjustable Output Voltage Automatic Cell Balancing Power Good Indicator Undervoltage Protection
Quiescent Current	20 µA
Component Count + Extras	17 + 33
Main I.C. Base Part	LTC4425
Design Author	Linear Technology
Date Created By Author	2009-11
Date Added To Library	2019-05