Well i am trying to control the heating and cooling of TEC using a H-bridge using a PID controller so i would expect the output from the controller can either be negative or positive, Any recommendations?Well, you really do not need a negative supply to an H-bridge. Ground will do fine.
If you simply wish to control a motor in direction and not speed, a simple DPDT switch is all you need to do that - no H-bridge at all. Does that satisfy your definition of an H-bridge switch?
If you are going to the trouble of an H-bridge, then PWM makes sense. Open loop PWM is simple with no microcontroller.
Its base on setpoint using a PI controller say if the temperature of the device cooled reaches the setpoint it should have zero error although it is impossible and i am using a thermocouple as its feedback with the AD595 as the thermocuple amplifier, So i was thinking to use a H-Bridge with PWM but i dont know whether it can be controlled in analogue since my circuit is based on analog not digital.Perhaps the larger issue is the nature of the control. Is is to be proportional, or setpoint on/off?