I'm working on a project which involves battery Ni-Mh 4x1.2v, 2100mAh], which power-ups the boards. The current consumption is about 150mA. Now what I wish to do is disconect the load when my battery voltage falls down to 4v or so
Because now when my battery reaches this voltage the instrument fails to work, sometimes my program gets corrupted. And battery reaches a critical voltage level like 1-1.2(summation of all 4 batt). what else can I do so prevent this?
Mail from MO
Depending on your budget you can solve this, a watchdog and power management chip from maxim may work for these types of problems.
You can even build your own watchdog and power management with logic and comparators.
When the uP malfunctions it has to be reset by a watchdog timer which monitors if the uP or uC is pulsing in the way expected.
Battery Backup for SRAM or Microcontroller
And when the power goes down slowly like a Brown out, you have to save all RAM on a Flash chip and shutdown system and wait. Or have another backup for RAM and use a low power RAM. Make sure that you write a start sequence and shutdown code in your program.
When you start start with a clear ram ( if not batt backed up) then load values from flash. Make sure power up, power down resets are ok.
Digital to Analog Converter with uC Watchdog
In an industrial environment your card it may malfunction due to EMI RFI. If your Board controls a huge Motor, when motor starts your Board could hang or Boot. You have to study and work out a solution.
The circuit or code is not everything, it is the Engineering that matters. 555 Watchdog.
See also - The MAX823 offers a watchdog input and manual reset input.The MAX824 offers a watchdog input and a complementary active-high reset. The MAX825 offers a manual reset input and a complementary active-high reset.
MAX793/MAX794/MAX795 microprocessor (μP)supervisory circuits monitor and control the activities of+3.0V/+3.3V μPs by providing backup-battery switchover,among other features such as low-line indication, μPreset, write protection for CMOS RAM, and a watchdog.