稳压器突然进入热关断模式

嗨，


我已经测试了20多个设计用于L6926稳压器的电路板，发现一些稳压器突然进入热关断模式。我认为它是热关机，因为它试图恢复生命，加热并在一秒钟内再次关闭。在允许一定的冷却时间后芯片通电时重复相同的操作。从稳压器汲取的电流仅为几mA（最大10mA）。

在未能理解这种失败之后，我们提供了并联线性稳压器。现在，每次我们使用DC DC稳压器发生故障时，我们只需将其拆下并安装线性稳压器即可。线性稳压器从未在船上失效。所以我确信这不是负载问题。过去几个月我一直在看这些失败。

是否有任何测试方法可供您理解此故障。我尝试使用比推荐值（6.8uH）更低的电感值（4.7uH），并且故障与两个电感值一样普遍。

你能推荐一个更稳定的更换零件吗？

谢谢。



以下为原文




Hi,


I have tested over 20+ boards that was designed to take L6926 regulators and find that some of the regulators abruptly go into thermal shutdown mode. I think it is thermal shutdown because it tries to spring back to life, heats up and shuts down again in a matter a second. The same repeats when the chip is powered up after allowing a certain cooling time. The currents being drawn from the regulators is only a few mA (10mA max).  

After failing to understand this failure, we made provision for a parallel linear regulator. Now, each time we have a failure with the DC DC regulator, we just remove it and mount the linear regulator. The linear regulators have never failed on board. So I am certain that this is not a load issue. I have been seeing these failures over the last several months.  

Is there any test method you would recommend for understanding this failure. I have tried using a lower value of inductance (4.7uH) than the recommended (6.8uH) value and the failures are just as common with both inductor values.  

Could you recommend a more stable replacement part?

Thanks.