Fan speed controlling circuit
AssigneesHONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD., Hon Hai Precision Industry Co., Ltd.
InventorXiang Zhang
Life of this patent
Estimating the term…
Abstract
A fan speed controlling circuit includes a temperature sensing circuit for transforming a temperature signal to a voltage signal, a reference voltage providing circuit for outputting a reference voltage, and a voltage amplifying and comparing circuit. The voltage amplifying and comparing circuit includes a negative terminal receiving the voltage signal from the temperature sensing circuit and a positive terminal receiving the reference voltage from the reference voltage providing circuit. A reactive circuit is connected to the voltage amplifying and comparing circuit. The reactive circuit produces a control signal according to a voltage signal output by the voltage amplifying and comparing circuit. The reactive circuit includes a driving component controlled by the control signal for providing a driving current to a fan.
Claims15
A fan speed controlling circuit, comprising:
- a temperature sensing circuit for transforming a temperature signal to a voltage signal;
- a reference voltage providing circuit for outputting a reference voltage;
- a voltage amplifying and comparing circuit comprising a negative terminal receiving the voltage signal from the temperature sensing circuit and a positive terminal receiving the reference voltage from the reference voltage providing circuit;
- a voltage follower circuit connected between the temperature sensing circuit and the voltage amplifying and comparing circuit for transferring the voltage signal to the voltage amplifying and comparing circuit without attenuation;
- and
- a reactive circuit connected to the voltage amplifying and comparing circuit, the reactive circuit producing a control signal according to a voltage signal output by the voltage amplifying and comparing circuit, the reactive circuit comprising a driving component controlled by the control signal for providing a driving current to a fan.
A fan speed controlling circuit, comprising:
- a transistor;
- a first amplifier having a positive terminal, a negative terminal and an output terminal, the positive terminal connected to the transistor, the negative terminal connected to the output terminal;
- a second amplifier having a positive terminal, a negative terminal, and an output terminal, the positive terminal receiving a reference voltage, the negative terminal connected to the output terminal;
- a third amplifier having a positive terminal, a negative terminal, and an output terminal, the negative terminal connected to the output terminal of the second amplifier, the positive terminal receiving a feedback voltage;
- and
- a MOSFET connected to the third amplifier for outputting a driving current to a fan.
A fan speed controlling circuit, comprising:
- a temperature sensing circuit for transforming a temperature signal to a voltage signal;
- a reference voltage providing circuit for outputting a reference voltage;
- a voltage amplifying and comparing circuit comprising a negative terminal receiving the voltage signal from the temperature sensing circuit and a positive terminal receiving the reference voltage from the reference voltage providing circuit, the voltage amplifying and comparing circuit further comprising a second amplifier, a resistor connected to the negative terminal of the second amplifier and a resistor connected between an output terminal and the negative terminal of the second amplifier;
- and
- a reactive circuit connected to the voltage amplifying and comparing circuit, the reactive circuit producing a control signal according to a voltage signal output by the voltage amplifying and comparing circuit, the reactive circuit comprising a driving component controlled by the control signal for providing a driving current to a fan.
Dependencies are inferred from the claim text.