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Pulse-width modulation speed controllable DC brushless cooling fan

  • US 5,099,181 A
  • Filed: 05/03/1991
  • Issued: 03/24/1992
  • Est. Priority Date: 05/03/1991
  • Status: Expired due to Term
First Claim
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1. A pulse-width modulation, speed controllable D brushless cooling fan for use inside a circuit system which is characterized in that said cooling fan is provided with a pulse-width modulation fan speed controlling circuit which comprises a driving IC, a Hall effect inductive IC connected with the two terminals on the input side of the driving IC and a rising-falling edge trigger monostable IC connected with the two terminals on the output side of the driving IC;

  • wherein the rising-falling edge trigger monostable IC further has a monostable pulse width timing resistor and a monostable pulse width timing capacitor on the output side thereof.

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