LMG1205: LMG1205

user5846952

Part Number: LMG1205

LMG1205 used in a DC-DC converter system functions as a gate driver for GaN power transistors. When testing in the prototype of the converter, we’ve faced with several problems:

1. The LMG1205 driver part is shown in Fig .1. When the port VDD of LMG1205 is added to 4.7V with no HI and LI input, the voltage of the ports HOH and HS is about 2.2V. Is it a normal phenomenon? If yes, could you explain the potential reasons for this phenomenon? If not, could you provide some suggestions to improve the design.

figure1

2. When the port VDD of LMG1205 is added to 4.7V, with HI and LI showed in the figure2, the voltage of HOH showed in the figure 3 is about constant 2.26V, which is not corresponding with the expectations. Could you provide some potential reasons for the problem.

figure2

figure3

over 6 years ago

0 Richard Herring over 6 years ago

TI__Mastermind 23015 points

Hello,

Thank you for the interest in the LMG1025. The engineer supporting this device is not available right now, and will look at your concerns as soon as he is back in the office.

Regards,

0 Jeffrey Mueller over 6 years ago

TI__Genius 12990 points

Hi User,

thanks for reaching out about LMG1205,

I see from the first waveform screenshot of LI and HI that the signals only go up to 500mV. LMG1205 needs 3.3V or 5V signal so the rising and falling thresholds will be crossed in order to switch the input and output.

Can you capture on one signal screenshot HO,LO,HI,LI with respect to ground?

also, are you able to share the portion of the LMG1205 pcb schematic?

thanks,