Instrument Cluster(Dash Board) Reserve Power Issues

instrument dash boards

I have designed and in process of testing Instrument Cluster(Dash board) using FPGA,Supporting 6 stepper motor(40mA each),CAN,LIN,RTC,LCD.

The circuit is consuming 1 Amp, My problem is battery is used for powering the ckt. when switched OFF, A reference signal is given to FPGA(Isolated from main power capacitor), in a very short time FPGA has to save some data and big problem is all the pointers of stepper motor has to come to its zero position.

So when powered off the capacitor (1000uF) is not able to provide enough reserve power such that the motor pointer can be brought back to zero position, I have tried with 2200uF but not so usefull.

It takes around 1Second for the Pointers to come back to its zero position(FPGA code Test result).

Can any one Please help me out with any possible suggestions.

lcd cluster dash

The power-off signal could be acknowledged by the FPGA after all motor positions are zeroed. That is, the FPGA shuts _itself_ off at the end of a power-down sequence.

Wade Hassler

stepper motor dashboard

provide enough reserve power such that the motor pointer can be brought back to zero position

Click to expand...

This job requires a lot of current, even a 10,000mfd is not enough i think.

Try some other method, use your main source till proper shutdown is done.

MicroCon