Patent ID: 6327424
Filing Date: 2001-12-04
Classification: H03K

Abstract:
A method of modulating the duration of pulses for control of power transistors applying voltage to a winding of an electronically commutated dc electric motor, said method comprising the steps of:(a) storing data with respect to sequences in a microprocessor;(b) writing with said microprocessor data characteristic of a succession of pulses of at least one pulse sequence to an intermediate register;(c) reading with a module separate from said microprocessor and equipped with a clock generator or a counter or with both a clock generator and a counter or a pulse width modulator, and connected to said intermediate register the contents of said intermediate register and based upon the data read from said intermediate register and characterizing said one pulse sequence:(c1) initiating and applying to said power transistors a corresponding succession of transistor-control pulses,(c2) limiting a duration of a first, starting one of said transistor-control pulses to a duration determined by data contents of said register, and(c3) varying the durations of the remaining transistor-control pulses of said succession of transistor-control pulses to ultimately reach a final transistor-control pulse of said succession of transistor-control pulses in accordance with the data in said intermediate register.