Digital pulse width modulator circuit with proportional dither

• Main Author: ANDERSON, ROBERT LEE
• Format: Patent
• Language: English; French; German
• Published: 05.10.1994
• Edition: 5
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; BASIC ELECTRIC ELEMENTS; BASIC ELECTRONIC CIRCUITRY; CALCULATING; CODE CONVERSION IN GENERAL; CODING; COMPUTING; CONTROL OR REGULATION THEREOF; CONTROLLING; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; COUNTING; DECODING; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; GENERATION; INDUCTANCES; MAGNETS; PHYSICS; PULSE TECHNIQUE; REGULATING; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES; TRANSFORMERS

System and method for digitally generating a pulse width modulated (PWM) signal with dither based on a command signal, the signal having a pulse width proportional to the command signal. In the preferred embodiment, the PWM signal with proportional dither energizes a load, such as a variable force solenoid, with a desired electrical current. The system includes a base signal generator (30) for generating a base signal having a pulse width which is based on a command signal representing the desired electrical current. The system also includes a dither signal generator (32) for digitally generating a dither signal having a pulse width proportional to the command signal, and a summer (50) for combining the base signal and the dither signal to obtain the pulse width modulated signal with proportional dither.