Freescale Semiconductor,inc.

Waley Li

Hongwei Zhao

Iven Zheng

Jian Yang

Linpeng Wei

Weiying Li

Tommy Mao

A method for passive cancellation of substrate noise for a buck converter uses an on-chip capacitor to reduce the substrate noise. The capacitor achieves a close-magnitude noise with opposite phase for better noise cancellation effect in the substrate. The capacitor can be realized as a MOS capacitor, NMOS isolation ring n-well capacitor, n-well junction capacitor, isolated p-well junction capacitor, etc. The capacitor is easy to implement. Further, bond wire parasitic inductance in the buck converter is used to reduce substrate noise.

Substrate noise passive cancellation method for buck converter

An H bridge circuit includes a gate driver circuit coupled to a gate of an NMOS device. The output of the gate driver circuit is at a voltage from 0.1V to 0.4V during a dead time of the H bridge circuit. The gate voltage of the NMOS device is biased at 0.1&#x2dc;0.4V to overcome the problems of minority carrier injection and power dissipation as compared with V=0 in a conventional H bridge circuit.

Gate driver circuit for H bridge circuit

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Beijing, China

Waley Li