Do not forget to have deadtime. In a H-bridge circuit, you need both legs off for a short time or you may see blue smoke. You need to calculate the turn off and turn on times (which will not be identical) for both upper and lower transistors and insert delays so that no transistor turn on before the other half of the leg is fully turned off regardless of where in the tolerance band. This phenomena is the main reason for using IC H-bridges becuse the are designed to take care of this.

Erik