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UCC37321: keeps popping...

Johnavon Vincent
Prodigy 30 points
Part Number: UCC37321
Other Parts Discussed in Thread: UCC37322,

around 2 or 3 months ago, I ordered 5 sets of ucc37321 and ucc37322, and around 1 week ago I got the time to use it in a project, but when I powered the project on, the ucc37321 ic keeps dying after 3-5 seconds or so, but the ucc37322 ic didn't, both of the ic was used to drive a gate drive transformer that should drive a half-bridge, I don't understand what happened then because the ic keeps dying and shorting after 3 attempts of ic replacement .the Vin for the ic was 12v and it was drawing around 600-800mA when it was working in the first 2 seconds. is it a problem with my circuit ? also I realized when the ic was working, I was probing the output of the ic and there was a 1.4Mhz oscillation when the ic was working, is it the ringing problem? since I only have 1 more ic again, I can't trust my circuit, since ordering one could take ages.. also I will attach the gate driving circuitry in here, thank you...

  the full circuit can be found on http://stevehv.4hv.org/SSTC5/miniSSTCsch.JPG

  • 0
    TI__Guru**** 189399 points

    Hi, Johnavon,

    Welcome to e2e, and sorry for the difficulties you are experiencing.

    The schematic looks fine. Can you send your pcb layout?

    Can you verify your power supply voltages are within the correct specifications for our IC?

  • 0 in reply to Don Dapkus
    Prodigy 30 points

    Hello, The Pcb Was built on a dotted board, and I have tested it to make sure there weren't any shorts.the voltage input from the power supply was 12v, I didn't put a 12v regulator for it, since I thought there would be no point, and the voltage regulator would just waste more heat. the signal input to the ic was fed from a 74ls14 so it had a voltage around 5v, but the interrupt pin had a voltage around 9v, is it a problem? because I have read the datasheet and it said +0.3Vdd so I thought it would be fine...there is also 1 more question that I had, in datasheet typical application schematic it suggests a 1uF ceramic capacitor, but since I didn't have it I replace it with a 100nF metal film capacitor and only a 100uF electrolytic capacitor after the power supply terminal could it be the main reason that the output was oscillating? Thank You...

  • 0 in reply to Johnavon Vincent
    TI__Genius 13445 points

    Hello,

    I work with Don in the gate drivers group.

    Please ensure the signals around the driver are within the recommended operating conditions NOT the abs max values as the drive might behave out of spec.  

    In terms of decoupling caps, for optimal performance from the driver IC, we recommend low ESR, ceramic surface mount capacitors. Typically, two capacitors across VDD and GND: a low capacitance ceramic surface-mount capacitor for high frequency filtering placed directly across the IC (to minimize stray inductance on the supply), and another high capacitance value surface mount capacitor for device bias requirements.

    Please let us know if you're still seeing failures once these recommendations are verified.

    Regards,

    -Mamadou

  • 0 in reply to Mamadou Diallo
    Prodigy 30 points

    Hello, thank you for responding quickly actually, okay I might have to change a couple of components in my circuit to optimize it a little bit more and also change the Interrupt pin voltage of the ic by feeding it to the 74ls14 with a resistor, but since I don't have anymore ucc37321p ic, I might not be able to test the circuit. in the next 1 or 2 weeks, so I might have to postpone this question... Thank you for the quick response...