issues with a TD352

[fab04]

Hi Everybody,

In the case of a LEDs tubes dimmer, I'm using a TD352.

It works very well. But in some case (and for the moment, I don't know why), my IGBT and the resistor wich controls the gate of the IGBT burn.

I just replace these two components and after it works well. It happens very rarely, but it happens.

IGBT can drive up to 80A (@ 25°C), and Vce is ok up to 650VAC, and the maximum inrush current that I measure is 35A, and the peak voltage, it's around 450VAC.

The value of the resistor is 51R in 0805 case.

The IGBT that I use is an IK40N65WR5.

If you have some suggestions to try to understand what happens, I'll be very happy.

 

 

 

[AScha.3]

Hi,

show full circuit, not only a part.

btw

LED dimmer, at 450V + 80A -> 36kW LED ??

[fab04]

Hi,

Maybe my explanations were not enough clear.

There are two channels on the product, and the maximum consumption per channel is 864W (each LEDs tubes consumes 18W, and 48 tubes per channel).

The system is supplied with 230VAC.

80A is the maximum that the IGBT can support (I choose this one, because the inrush current at starting can be very high - 35A), but in normal functionning, the current is low (around 3/4 A).

 

 

 

[AScha.3]

Hi,

ok - i see. You have a lot of protective diodes... so overvoltage should (!) be no problem.

Burned gate resistors are collateral damage from strange IGBT suicide . :)

So my ideas : change gate circuit...to just a 20 ohm (1206) resistor, as ds shows , is used for tests:

no extra diodes, no clamp connection. (IGBT switching anyway at its own speed - its not a mosfet.)

+

where is VCC for driver coming from ? 0/15V ? should be close to driver , or some small (5 ohm or so) in ground and vcc connection, to avoid any spikes coupling in.

+

Gate circuit :  driver-20r-IGBT gate - - source - driver : has to be small/close to IGBT , small included area.

+

What frequency you drive the dim pwm ? (and : any short "ON" states , like 100ns ON, IGBTs dont like. You avoid this short on-times ?)