Switching PIC16F PWM output between each side of a H Bridge

[HenrikOlsson]

Hi Andrew,
Locked anti-phase PWM is when you, for zero torque ouput, applies a 50% dutycycle to the bridge. Upper left and lower right switch is on half of the time, then upper right and lower left switch is on half of the time. This means that current is passing thru the motor in one direction 50% of the time and in the other direction 50% of the time. The net current thru the motor is 0 so no torque is produced.

As you change the dutycycle, up or down, current is passing in one direction for a longer time than in the other meaning the net current thru the motor increases which makes it start to produce torque. This alows a single PWM signal to control direction and torque.

Basically you apply the PWM signal to top right and low left switch. Then you run the same signal thru an inverter and apply THAT signal to upper left and lower right switch. There's no dead-time when doing this which means your bridge has to implement that in hardware. With the 16F690 dead-time is avaliable and controlled thru the PWM-module and it outputs the complementary signals directly so you won't need the external inverters.

How is your H-bridge designed? Hybrid chip or discrete components? If MOSFETs what type of driver chip are you using?

/Henrik.