STMicroelectronics AN2818 Application Note NiMH Charger Demo Board

About this manual

The document details an application note for a NiMH battery charger demonstration board powered via USB. The system utilizes the ST72F60E2M1 microcontroller to manage charging operations, including current limiting and status monitoring.

It explains the theory of operation using methods like negative delta V and zero delta voltage detection to terminate charging. The guide provides implementation details for customizing the STEVAL-ISBO03V1 board, connecting NiMH batteries, and monitoring charging status through a PC interface.

What's inside

• Theory of operation
• NiMH battery charging methods
• USB-based charger implementation
• STEVAL-ISBO03V1 customization
• Hand-shaking with the PC
• Connecting the NiMH battery
• Monitoring battery status
• External USB controller usage

Specifications

Frequently asked questions

What method does the demonstration board use to detect the end of charging?

The board uses the zero delta voltage method as the primary technique, with time out and max temperature as backup methods.

What is the primary method used to detect when NiMH charging ends on this demonstration board?

The board uses a zero delta voltage condition for a certain time duration as the primary technique for terminating the charge.

What current limit does the USB bus provide by default before enumeration increases it?

Only a 100-mA current is available by default from the USB bus.

What voltage threshold per cell indicates that an NiMH battery is connected?

If the battery voltage is less than 0.9 V/cell, the battery is considered connected.