Part Number: LM5113
I am using the LM5113 gate driver to drive an EPC2034 in a DC-DC converter. The IC is connected as required and an isolated DC-DC converter is used to provide 5 V voltage for the IC. The Vss port of the IC is connected to the power ground. The IC only needs to drive one switch and thus LI, LOH and LOL ports are not connected. The source of EPC2034 is connected to a point with 5-10 V potential over power ground. It is found that the gate-source voltage of the device is negative and the device is not turned on. However, if the source of the switch is connected to power ground, the gate-source voltage is about 5 V and switch is turned on. In short, the IC seems not capable of providing an isolated gate-source voltage that ensures the turn-on of switch.
I would appreciate any idea/advice on why this happens and how I can drive such a single floating GaN device. Thanks!
Gate Driver Applications Engineering Manager
Dallas, TX USA
In reply to Don Dapkus:
In reply to Liyao Wu:
Please check below the two drawings that can better explain my question. I assume we have a load voltage of 20 V over the power ground. According to your suggestion, I am now using the load voltage as the VSS input. I hope to check three things. First, in this case, do we need to use a VDD around 25 V to make the IC work properly? Secondly, should the HI or LI input also carry a logic signal with load voltage (20 V) as the reference level (e.g., 25 V when high and 20 V when low)? Thirdly, will there be any differences between the following two ways of connection, i.e., using HOH/HOL and using LOH/LOL to drive the device?
Thank you for your time! I hope this makes my question clearer.
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