MIC4609施加任何负载故障引脚被拉下来

你好，AllI设计了一个具有各种模块的评估板。在MOSFET驱动器的一个模块中，我使用MIC4609集成电路。现在IC似乎工作正常，直到我对它施加任何负载，然后故障引脚被拉下来，所有的输出都被打开。数据表指出故障的原因是乙醚A在欠电压或过电流。因此，我首先检查的是电源电压（12V）的范围，并确保这不会下降与故障引脚。结果证明没问题。现在，目前的引脚看起来有相当数量的电机噪音，所以只是为了证明概念，我只是短路了低通帽上的ISNS引脚到GND。我仍然有故障和桥梁的禁用。我已经复制了参考设计，但改变了引导到0.1UF（我使用非常低的栅极电荷MOSFET），改变了栅极电阻为100OHM，我只有一个并联电阻三个半桥。我已经监测到电流，以确保没有电流尖峰（穿透等）。我有问题，非常高的电流汲取（和降压电流限制，降低电源电压低于阈值造成故障）。但是，一旦我把反向二极管放在门上，这似乎可以解决问题，电源电压现在稳定了。有人有什么想法（有什么好的意见）吗？谢谢



      以下为原文

    Hello All

I have designed an evaluation board with various modules. On one of the modules for the mosfet drivers I am using the MIC4609 IC. Now the IC seems to work OK until I put any sort of load on it, then the fault pin is pulled down and all the outputs are opened. The datasheet says the causes for the fault is ether a under voltage or over current. So the first thing I check is the supply voltage (12V) with a scope and ensure this does not drop with the fault pin. This turns out to be OK. Now the current pin looked to have a fair amount of motor noise on it, so just to prove concept I just shorted out the low pass cap on the ISNS pin to GND. I am still getting the fault and the bridge's disabling.

I have pretty much copied the reference design, but changed the bootstraps to 0.1uF (I am using very low gate charge mosfets), changed the gate resistors to 100Ohm, I only have a single shunt resistor for all three half bridges. I have monitored the current to ensure there are no current spikes (shoot through etc...).

I was having problems with very high current draw (and the buck current limiting decreasing the supply voltage below the threshold causing a fault). But once I put the reverse diodes on the gates this seemed to cure the problem and the supply voltage is now stable.

Does anyone have any idea (of have any good opinions) on what else could be causing the fault?

Thanks