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Re: Self-Resonant Driver Boards (DRSSTC, ISSTC, etc...) Bulk Purchase ? ? ? ? Anyone ? ? ?
Original poster: "Eastern Voltage Research Corporation" <dhmccauley-at-easternvoltageresearch-dot-com>
> Good, because the way you had put it, it seemed as though the circuit was
> only to protect the driver chips and not the transistors in the bridge, I
> guess that would go hand in hand though...
> It might be wise to allow some sort of heatsinking on the driver chips,
> incase they would get warm, But if you're using the UCC27321, I don't
> think that would be needed, as they have a wider temperature operating
Heatsinks really aren't needed. If you do the calculations for power
dissipation at 10-15% duty cycle running 20nF gate loads (-30 to +30V
with the UCC chips, there really is no heat dissipation at all.
Remember heat dissipation of the gate driver is:
C * V^2 * Freq * Duty * DividingFactor
C = capacitance of gate loads (typically 20nF + 20nF per paralleled set)
V = 60V (Yes, you are swinging from -30V to +30V with the current
configurations that Steve and I use)
Freq = 50-200kHz (depends on coil)
Duty = 15%
Dividing Factor = (ON Resistance of Drivers/(SeriesGateResistor+ON