Precise Motor Speed Regulator

C J JL MONOST TRIGGER & DIFFER. 2.3V 10k THERMAL PROTEC. (a) (b) (C) 20 rn EE 62 November 1987 PRECISE MOTOR SPEED REGULATOR by Arturo Wolfsgruber By virtue of an innovative dual control loop scheme, the TDA7272 motor speed regulator chip achieves both fast response and long-term stability without speed sensors. The speed of small DC motors is usually controlled either by regulating the current or with a velocity feedback loop using a tacho generator or speed sensor. But both of these systems have disadvantages. Current control offers a fast response to transients but poor long term stability, while vel- ocity feedback schemes need a costly tacho generator and only provide an adequate transient response if a high-frequency AC tacho is used. A new motor speed regulator chip, the SGS TDA7272 (Fig. 1), combines the best features of the two techniques, having a current control loop to guarantee fast transient response, plus a velocity feed- back loop to guarantee long term stability. ...