Hi,
What is the current capability of the internal charge pump? I want to know whether it will be able to keep a high side MOSFET on continuously. How does it depend on temperature? In the datasheet it is indicated the problem might get worse at high temperature.
While I understand that there’s a mechanism for recharging the bootstrap through the low side, that will disturb the output voltage depending on the load current. Speaking of which, what is the duration of the high side turn off, low side turn on for recharging the bootstrap?
Regards
Hi Nicolas,
From the datasheet, the IC will work under 290C, but I will not suggest your application exceeds 130C for its good performance. I didn’t find any information about the current capability of the internal charge pump, but I could say that we cannot keep high side MOSFET on continuously for a really long time. BST cap discharges really slow, but after some cycles, we still need to open the LS FET to recharge it in some microseconds. I hope my answer can help you, but if you still want to know the precise information about the current capability, please let me know, I can contact our team and give you the answer. Thanks!
Best,
Fox
Hi,
Yes please, understanding this well will allow me to use this device. Devices from other manufacturers are able to keep the MOSFET on if the pull down resistor is high enough.
Is the 290ºC data correct?
Hi,
Sorry for the late response, I checked the performance of MP1922 with our application engineer team.
For MP1922, the current capability of the internal charge pump is 10uA to 20uA. For most of your application, the HS FET can be 100% turned on. But for some high temperature, it cannot maintain 100% on. You can find the information in the datasheet:
The upper temperature for 100 HS FET on is decided by lot of different reasons. It is mainly related to the performance of your MOSFET. For some MOS, they can be turned on 100% up to 290C. But you should do some tests by yourself and leave some margin.
Hope it is useful!
Best,
Fox