• Resolved

LMG5200: Switches short when using 2 devices cascaded

Part Number: LMG5200

Hi,

I am using two LMG5200 cascaded (Q1+Q2 is one package and Q3+Q4 is the other package) as can be seen in the schematics below. Here Q1 and Q3 are switched at the same time, while Q2 and Q4 are also switched at the same time. The Q1+Q3 pair and Q2+Q4 pair are never switched at the same time.

For my test I was switching at 100kHz, with around 2µs between Q1+Q3 and Q2+Q4. However, I saw that the resonant tank (Cr+Lr) was being discharged when Q2+Q4 are switched on. It seems that Q2 and Q3 are conducting at the same time, while the control signal for Q2 is high and the control signal for Q3 is low.

Does anyone have any idea what might go wrong, why Q2 and Q3 seem to short the resonant tank?

I have used a 2-channel isolator for the HI and LI signals of the upper LMG5200 with a 5V supply with respect to the main input voltage.

Used control signals:

Thanks,

Wouter