Faster, simpler switch controls

A demonstration board for CogniPower's patent-pending switch controls was shown for the first time at the APEC Conference in February, 2009. We achieve faster switching speeds for better efficiency, and use only marginally more than the theoretic minimum power required for gate drive. Snubbing requirements can be greatly reduced or even eliminated. Absence of overshoot allows lower voltage switches to be employed for a given working voltage. Lower voltage parts are smaller, faster, less expensive and more efficient. CogniPower switch controls incorporate the power supplies, so no separate high-side supply is necessary.

Totem Pole Switch Control Board

The demonstration board pictured above can drive a totem pole switch built of FETs or IGBTs. With FETs capable of 50 volts at 12 amps, the screen shot below shows rise and fall times faster than 5000 volts per microsecond.

Oscilloscope Screenshot 1

1 kW totem pole output swinging between 0 and 40 volts at 200 kHz without snubbing. (1 µs/div, 10 V/div)

Oscilloscope Screenshot 2

Another view of the waveform from the previous image, with the timescale set to 20 ns/div. Transition time is 7 ns and overshoot is less than 2%.

Oscilloscope Screenshot 3

The negative transition time is 9 ns and undershoot is minimal.


More pictures of the totem pole switch