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response are determined by a compensation net- work connected between its output and ground. This OTA has a large bandwidth (300KHz) and so its pole does not interfere with the pole and zero of the Motor + Power Mos system and of the compensation network. In the application the RC network gives an high system gain at low fre- quency to ensure good precision and a low gain at high frequency to ensure stability of the sys- tem. The figure 5 shows the Bode plot of the com- pensated error amplifier plus power stage and m otor. The RC value of the compensating network must be choosen to have for high frequencies a flat gain of about 20dB so that the double pole of the motor makes the Bode diagram change its slope and decrease with 40dB/decade stabilizing the whole system cutting the bandwidth. An empiric way to find good RC value for compensation net- work can be the follow: 1)set a great value of C in order to not interfere at high frequencies 2)give, with motor completely stopped, an exci- tation as voltage step and act on R in order to get an acceptable current overshoot 3)decrease the value of C until to have a good gain at low frequencies. Figure 5.