Patent ID: 6788017
Filing Date: 2004-09-07
Classification: H02P

Abstract:
A period adjustment circuit for use with a disconnection and restart IC connected to a DC brushless motor, the disconnection and restart IC having a current source output coupled to a first capacitor, said period adjustment circuit being connected to said current source output of said disconnection and restart IC, said period adjustment circuit comprising a second capacitor connected in series with a resistor and in parallel with a pair of terminals of a transistor, a third terminal of said transistor being connected to a current source output of said disconnection and restart IC and said first capacitor;said first capacitor being charged from an output of said current source output of said disconnection and restart IC, said second capacitor also charges said first capacitor through said resistor until a voltage of said first capacitor reaches an activation voltage of a disconnection and restart protection function of said disconnection and restart IC, said DC brushless motor being placed in a disconnection state by said disconnection and restart IC responsive to said voltage reaching said activation voltage, said second capacitor continually charges said first capacitor through said resistor until voltages of said two capacitors are equal, said first capacitor and said second capacitor being simultaneously charged by said output of said current source output of said disconnection and restart IC until the voltage of said first capacitor reaches a system reset voltage, said disconnection and restart IC discharging said first capacitor to a restart voltage and said second capacitor to the restart voltage plus an emitter-to-base conduction voltage of said transistor responsive to said first capacitor reaching the system reset voltage.