Features

• Accurate Output Current Programming
• Usable in Charging Applications Up to 32V Output
• Programmable Load Current Monitor for End-of-Charging-Cycle Notification (16-Pin Version)
• Dual Function IC (LT1621) Allows Convenient Integration of Load and Input Current Sensing
• Level-Shifted Current Sense Output for Current Mode PWM Controllers
• Can be Used for NiCd, NiMH, Lead-Acid and Lithium- Ion Battery Charging
• Greater than 96% Efficiency Possible in Charger Applications
• High Output Currents Possible: > 10A Easily Obtained

Typical Application

Description

The LT1620 simplifies the design of high performance, controlled current battery charging circuits when used in conjunction with a current mode PWM controller IC. The LT1620 regulates average output current independent of input and output voltage variations. Output current can be easily adjusted via a programming voltage applied to the LT1620’s PROG pin. Most current mode PWM controllers have limited output voltage range because of common mode limitations on the current sense inputs. The LT1620 overcomes this restriction by providing a level-shifted current sense signal, allowing a 0V to 32V output voltage range. The 16-pin version of the LT1620 contains a programmable low charging current flag output. This output flag can be used to signal when a Li-Ion battery charging cycle is nearing completion. The LT1621 incorporates two fully independent current control circuits for dual loop applications.