LOW COST MOTOR HOME DETECTION, MOTOR SPEED CONTROL AND POWER SUPPLY FOR VENDING MACHINE CONTROL SYSTEMS

摘要

A vending machine control apparatus (100) has a product delivery motor home circuit (55) and a DC power supply (10, 110, 210, 310) modulated in response to varying line voltage and/or load by a pulse width modulation circuit (16, 116, 216, 316). The modulated DC power signal supplies power to one or more DC product delivery motors (47) in a vending machine. Each product delivery motor (47) has an associated switch (S1) which passes pulses, resulting from the modulation of the power supply (10, 110, 210, 310), when the delivery motor (47) is in its home position. A simple motor home detection circuit (55) detects these pulses, and preferably a microprocessor control circuit (60) connected to the detection circuit (55) determines that a home condition exists.