Hi,
My customer need assistance.
This is an application case where I use DRV421 for a closed-loop current sensor. The circuit diagram is shown in the figure.
fig1 Product outline drawing
The product can output the current value normally when the input current reaches 300A in the normal test. At this time, the sensor output is 296mA (the compensation coil has a transformation ratio of 1000:1, and the inductance is less than 100mH). No output lock phenomenon will occur.
When the bus is charged and discharged, there is a 250A surge current (caused by the parasitic capacitance of the electronic load) on the bus（fig2）, and the sensor is abnormal. After the output is locked, the fixed output is about 250mA. The sensor returns to normal after restarting。
I want to understand the reason, is it caused by the unstable work of DRV421, and how to avoid this problem.
Can you tell me? Thanks！
Fig2
Fig3
Please help. Thanks.
