voltage drop and circuit reset

[wealth210]

Hi All,
My project is using Masking Chip IC GPC11768A1, Whose IC operate VDD is 2.4v ~5.5v. During the design state, The project will use Kernal chip IC GPC11001A + 8MB Flash IC ! The project is a toy, which have two DC motor control four direction. OK, the problem is when use Kernal chip IC + Flash(IC VDD:2.2v~3.6v) ,The function of the toy is ok even though at the low battery voltage 3.6v. When use Masking Chip IC GPC11768A1,it will reset when the battery voltage <5.34v (Battery initial voltage is 6.4v ). We still find why cause that, Pls share your thinking.

Toy Project describe:
1. IC VDD: 3.6v LDO output
2. the system currently is Ipeak around 3.4A
3. Kernal chip + Flash IC VDD:2.2V~3.6v, it's still ok when LDO output is 1.9v. It wouldn't reset even though motor turn slow.
4. Masking Chip IC VDD: 2.4v~5.5v . Battery voltage will drop when two motor turn,and Toy will reset.

 

[crutschow]

It could be that the motor is generating fast negative spikes below the Masking Chips rated voltage which trip the reset function. Try decoupling the Masking Chip's voltage from the motor with a capacitor and small series resistor. Size the resistor to cause no more than 100mV or so drop at the chips normal operating current.