TWI548196B - Forward-based power supply apparatus and fan driving method thereof - Google Patents

Description

Power supply unit based on a forward architecture and its fan drive method

The present invention relates to a power supply technology, and more particularly to a power supply device based on a forward architecture and a fan driving method thereof.

It is well known that currently there are heat sinks (such as heat sinks, fans, etc.) mounted on internal components (such as CPUs) and/or devices (such as power supplies) of a computer device. Among these heat sinks, the fan is one of the important parts that are indispensable because it can remove the heat generated by the internal parts and/or devices of the computer device from the housing of the computer device, thereby enabling the computer device system to Works normally.

Taking a power supply device as an example, a fan driving voltage for driving a fan installed in a power supply device is provided/supplied via an independent and corresponding control circuit, and the control circuit is A thermistor having a negative temperature coefficient (NTC) is used to sense the heat source of the power supply device, and the supplied fan driving voltage is adjusted according to the resistance change of the thermistor having a negative temperature coefficient. .

It can be seen that the conventional method for driving the fan mounted on the power supply device must additionally design an independent control circuit corresponding to the fan, and this will increase the overall cost of the power supply device.

In view of this, the present invention provides a power supply device based on a forward architecture and a fan driving method thereof, which does not need to additionally design a separate control circuit corresponding to a fan to drive the cooling fan, thereby improving/solving the prior art. The problems mentioned.

Based on the above, an exemplary embodiment of the present invention provides a power supply device including: a fan, a forward power conversion circuit, and a fan power generation unit. The forward power conversion circuit may further include a transformer, a power switch, a first power generating unit, and a second power generating unit. The transformer has a primary side, a first secondary side, and a second secondary side, and the opposite end of the primary side of the transformer is configured to receive an input voltage. The first end of the power switch is coupled to the same end of the primary side of the transformer, the second end of the power switch is coupled to a ground potential, and the control end of the power switch is configured to receive a control signal.

The first power generating unit is coupled to the first secondary side of the transformer for generating a first power source in response to the input voltage and a first turn ratio of the primary side of the transformer to the first secondary side. The second power generating unit is coupled to the second secondary side of the transformer for generating a second power source in response to the input voltage and a second turn ratio of the primary side of the transformer to the second secondary side. The fan power generating unit is coupled to the first secondary side of the transformer, the second power generating unit, and the fan, configured to generate a fan driving voltage by reacting a reverse voltage of the first secondary side of the transformer with the second power source In order to drive the fan. Wherein, the fan driving voltage is changed in response to load variation of the forward power conversion line.

In an exemplary embodiment of the present invention, the first power generating unit may include: a first diode, a second diode, a first Zener diode, a first inductor, and a first capacitor. The anode of the first diode is coupled to the opposite end of the first secondary side of the transformer. The anode of the second diode is coupled to the same end of the first secondary side of the transformer, and the cathode of the second diode is coupled to the cathode of the first diode. The anode of the first Zener diode is coupled to the same end of the first secondary side of the transformer, and the cathode of the first Zener diode is coupled to the cathode of the first diode. The first end of the first inductor is coupled to the cathode of the first diode, and the second end of the first inductor is configured to generate and output the first power source. The first end of the first capacitor is coupled to the second end of the first inductor, and the second end of the first capacitor is coupled to the same end of the first secondary side of the transformer. Wherein, the voltage on the different name end of the first secondary side of the transformer is the reverse voltage.

In an exemplary embodiment of the present invention, the second power generating unit may include: a third diode, a fourth diode, a second Zener diode, a second inductor, and a second capacitor. The anode of the third diode is coupled to the opposite end of the second secondary side of the transformer. The anode of the fourth diode is coupled to the same end of the second secondary side of the transformer, and the cathode of the fourth diode is coupled to the cathode of the third diode. The anode of the second Zener diode is coupled to the same end of the second secondary side of the transformer, and the cathode of the second Zener diode is coupled to the cathode of the third diode. The first end of the second inductor is coupled to the cathode of the third diode, and the second end of the second inductor is configured to generate and output the second power source. The first end of the second capacitor is coupled to the second end of the second inductor, and the second end of the second capacitor is coupled to the same end of the second secondary side of the transformer.

In an exemplary embodiment of the invention, the first and second inductors are mutually coupling.

In an exemplary embodiment of the present invention, the fan power generating unit may include: a fifth diode, a third capacitor, and a fourth capacitor. The cathode of the fifth diode is coupled to the opposite end of the first secondary side of the transformer. The first end of the third capacitor is coupled to the anode of the fifth diode, and the second end of the third capacitor is coupled to the ground potential. The first end of the fourth capacitor is coupled to the anode of the fifth diode, and the second end of the fourth capacitor is coupled to the first end of the second capacitor. The voltage across the fourth capacitor is the fan driving voltage.

In an exemplary embodiment of the present invention, the control signal may be a pulse width modulation signal, and the duty cycle of the pulse width modulation signal is changed in response to a load variation of the forward power conversion line, thereby The fan drive voltage is changed.

Another exemplary embodiment of the present invention provides a power supply device including: a fan, a power conversion circuit, and a fan power generation unit. The power conversion line is used to supply the power required by a load. The fan power generating unit is coupled between the fan and the power conversion line for providing a fan driving voltage to drive the fan in response to a portion of the power supplied by the power conversion line. Wherein, the fan driving voltage changes in response to a load variation of the power conversion line.

Still another exemplary embodiment of the present invention provides a fan driving method including: providing a power conversion line to supply power required for a load; and providing a fan driving voltage to drive the fan according to a part of power supplied from the power conversion line . Wherein, the fan driving voltage changes in response to a load variation of the power conversion line.

In an embodiment of the invention, the power conversion circuit can be a forward power conversion circuit, and the forward power conversion circuit operates in response to a pulse width modulation signal, and the pulse width adjustment The duty cycle of the change signal changes in response to load variations of the forward power conversion line, thereby changing the fan drive voltage.

In an exemplary embodiment of the present invention, when the load of the forward power conversion line is heavy, the duty cycle of the pulse width modulation signal is relatively large, and the fan driving voltage is relatively large. . On the contrary, when the load of the forward power conversion line is light load, the duty cycle of the pulse width modulation signal is relatively small, and the fan driving voltage is relatively small.

In an exemplary embodiment of the present invention, the forward power conversion circuit is configured to supply power required by the load in response to the enabling of the pulse width modulation signal; and the forward power conversion circuit is reactive The disablement of the pulse width modulation signal is performed by a fan to demagnetize the transformer therein.

Based on the above, the power supply device of the present invention is based on a forward architecture, and the fan driving voltage required for driving the fan can be obtained only from the forward power conversion line, and the fan drive The voltage will change as the load of the forward power conversion line changes (ie, light or heavy). In this way, there is no need to additionally design an independent and corresponding control circuit to drive the fan installed in the power supply device, and this will reduce the overall cost of the power supply device. On the other hand, since the fan can be regarded as a fixed load, the transformer can be demagnetized when the power switch is turned off.

It should be understood that the above general description and the following specific embodiments are only The invention is not intended to limit the scope of the invention as claimed.

DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to the exemplary embodiments embodiments In addition, wherever possible, the same reference numerals in the drawings

1 is a schematic diagram of a power supply apparatus 10 according to an exemplary embodiment of the present invention, and FIG. 2 is a schematic diagram of an implementation of the power supply apparatus 10 of FIG. 1 and 2, the power supply device 10 is forward-based, and may include a fan 101, a forward power conversion circuit. 103, and a fan power generating unit 105.

In the exemplary embodiment, the fan 101 is configured to perform a heat dissipation operation on a heat source generated when the power supply device 10 operates. In addition, the forward power conversion line 103 is used to generate power required for a load 20 (such as, but not limited to, a computer system). Furthermore, the fan power generating unit 105 is coupled between the fan 101 and the forward power conversion line 103 for reacting a part of the power generated by the forward power conversion line 103 to provide a fan driving voltage Vfan to drive the fan 101. .

More specifically, the forward power conversion line 103 may include a transformer T, an N-type power switch Q, a first power generating unit PG1, and a second. The power generation unit PG2, the third power generation unit PG3, and the pulse width modulation control chip 209 (pulse width modulation control chip). The transformer T has a primary winding NP, a first secondary winding NS1, a second secondary side NS2, and a third secondary side NS3. The opposite-positive end of the NP of the transformer T is used to receive the input voltage VIN.

The first end of the power switch Q is coupled to the common-polarity terminal of the primary side of the transformer T, and the second end of the power switch Q is coupled to the ground potential, and the power switch Q The control terminal is configured to receive the control signal PW (for example, a pulse width modulation signal (PWM signal), but is not limited thereto). In the present exemplary embodiment, the power switch Q is switched in response to the control signal PW, that is, alternately turned-on and turned-off.

In addition, the first power generating unit PG1 is coupled to the first secondary side NS1 of the transformer T for reacting to the input voltage VIN and the turns ratio of the primary side NP of the transformer T to the first secondary side NS1 (turns ratio, NP) /NS1) generates the first power source V1. More specifically, the first power generating unit PG1 includes: diodes D1 and D2, a Zener diode ZD1, an inductor L1, a capacitor C1, and an output stage ( Output stage) 201. The anode of the diode D1 is coupled to the different end of the first secondary side NS1 of the transformer T. The anode of the diode D2 is coupled to the same name end of the first secondary side NS1 of the transformer T, and the diode The cathode of D2 is coupled to the cathode of diode D1.

The anode of the Zener diode ZD1 is coupled to the same end of the first secondary side NS1 of the transformer T, and the cathode of the Zener diode ZD1 is coupled to the cathode of the diode D1. The first end of the inductor L1 is coupled to the cathode of the diode D1, and the second end of the inductor L1 is used to generate and output the first power source V1. The first end of the capacitor C1 is coupled to the second end of the inductor L1, and the second end of the capacitor C1 is coupled to the same end of the first secondary side NS1 of the transformer T. The output stage 201 is connected in parallel with the capacitor C1 for regulating the first power source V1 to output the regulated power source V1'. In the present exemplary embodiment, the voltage on the different name end of the first secondary side NS1 of the transformer T is first defined as the reverse voltage of the first secondary side NS1 of the transformer T. Moreover, the output regulated power supply V1' can be substantially smaller than the first power supply V1. For example, the output regulated power supply V1' may be +5V, and the first power supply V1 may be about +6.5V, but is not limited thereto. Therefore, the reverse voltage of the first secondary side NS1 of the transformer T can be understood as -6.5V.

Similarly, the second power generating unit PG2 is coupled to the second secondary side NS2 of the transformer T for reacting to the input voltage VIN and the turns ratio of the primary side NP of the transformer T to the second secondary side NS2 (NP/NS2) And generating a second power source V2. More specifically, the second power generating unit PG2 includes: diodes D3 and D4, a Zener diode ZD2, an inductor L2 coupled to the inductor L1, a capacitor C2, and an output stage 203. The anode of the diode D3 is coupled to the different end of the second secondary side NS2 of the transformer T. The anode of the diode D4 is coupled to the same end of the second secondary side NS2 of the transformer T, and the cathode of the diode D4 is coupled to the cathode of the diode D3.

The anode of the Zener diode ZD2 is coupled to the same name end of the second secondary side NS2 of the transformer T, and the cathode of the Zener diode ZD2 is coupled to the cathode of the diode D3. The first end of the inductor L2 is coupled to the cathode of the diode D3, and the second end of the inductor L2 is used to generate and output the second power source V2. The first end of the capacitor C2 is coupled to the second end of the inductor L2, and the second end of the capacitor C2 is coupled to the same end of the second secondary side NS2 of the transformer T. The output stage 203 is connected in parallel with the capacitor C2 for regulating the second power source V2 to output the regulated power source V2'. In the present exemplary embodiment, the output regulated power supply V2' may be substantially smaller than the second power supply V2. For example, the output regulated power supply V2' may be +3.3V, and the second power supply V2 may be about +3.5V, but is not limited thereto.

Furthermore, the third power generating unit PG3 is coupled to the third secondary side NS3 of the transformer T for reacting to the input voltage VIN and the turns ratio of the primary side NP of the transformer T to the third secondary side NS3 (NP/NS3) And generating a third power source V3 and a fourth power source V4. More specifically, the third power generating unit PG3 includes: diodes D6 to D10, Zener diodes ZD3 and ZD4, capacitors C5 to C7, an inductor L3 coupled to the inductor L1, and an inductor coupled to the inductor L3. L4, and output stages 205 and 207.

The anode of the diode D6 is coupled to the opposite end of the third secondary side NS3 of the transformer T. The anode of the diode D7 is coupled to the same end of the third secondary side NS3 of the transformer T, and the cathode of the diode D7 is coupled to the cathode of the diode D6. The anode of the diode D8 is coupled to the opposite end of the third secondary side NS3 of the transformer T, and the cathode of the diode D8 is coupled to the cathode of the diode D6. The anode of the diode D9 is coupled to the same name end of the third secondary side NS3 of the transformer T, and The cathode of the diode D9 is coupled to the cathode of the diode D6. The anode of the Zener diode ZD3 is coupled to the opposite end of the third secondary side NS3 of the transformer T, and the cathode of the Zener diode ZD3 is coupled to the cathode of the diode D6. The cathode of the Zener diode ZD4 is coupled to the cathode of the diode D6. The first end of the capacitor C5 is coupled to the anode of the Zener diode ZD4, and the second end of the capacitor C5 is coupled to the same end of the third secondary side NS3 of the transformer T.

The first end of the inductor L3 is coupled to the cathode of the diode D6, and the second end of the inductor L3 is used to generate and output the third power source V3. The first end of the capacitor C6 is coupled to the second end of the inductor L3, and the second end of the capacitor C6 is coupled to the same end of the third secondary side NS3 of the transformer T. The anode of the diode D10 is used to generate and output a fourth power source V4. The first end of the inductor L4 is coupled to the cathode of the diode D10. The first end of the capacitor C7 is coupled to the second end of the inductor L4, and the second end of the capacitor C7 is coupled to the anode of the diode D10. The output stage 205 is connected in parallel with the capacitor C6 for regulating the third power source V3 to output the regulated power source V3'. The output stage 207 is connected in parallel with the capacitor C7 for regulating the fourth power source V4 to output the regulated power source V4'. In the present exemplary embodiment, the output regulated power supply V3' may be +12V, and the output regulated power supply V4' may be -12V, but is not limited thereto.

In addition, a PWM control chip 209 is coupled to the power switch Q for generating a control signal (pulse width modulation signal) PW in response to a power supply request of the load 20, And in response to the change of the load 20, the duty cycle of the control signal (pulse width modulation signal) PW is adjusted. It can be seen that the forward power conversion line 103 is generated by the pulse width modulation control chip 209. The control signal (pulse width modulation signal) PW operates.

On the other hand, the fan power generating unit 105 is coupled to the first secondary side NS1 of the transformer T, the second power generating unit PG2, and the fan 101 for reacting to the reverse voltage of the first secondary side NS1 of the transformer T (ie, The voltage on the different end of the first secondary side NS1 is generated by the second power supply V2 generated by the second power generating unit PG2 to generate the fan driving voltage Vfan, thereby driving the fan 101.

More specifically, the fan power generating unit 105 includes a diode D5 and capacitors C3 and C4. The cathode of the diode D5 is coupled to the different end of the first secondary side NS1 of the transformer T (ie, the end point B). The first end of the capacitor C3 is coupled to the anode of the diode D5, and the cathode of the second end of the capacitor C3 is coupled to the ground potential. The first end of the capacitor C4 is coupled to the anode of the diode D5, and the second end of the capacitor C4 is coupled to the first end of the capacitor C2 (ie, the end point C). The voltage across the capacitor C4 is the fan drive voltage Vfan.

In the present exemplary embodiment, the fan driving voltage Vfan supplied/generated by the fan power generating unit 105 changes in response to the load 20 of the forward power converting line 103. More clearly, the control signal PW received by the control terminal of the power switch Q can be a PWM signal, so that the duty cycle of the control signal (pulse width modulation signal) PW is reflected in the forward direction. The load 20 of the power conversion line 103 is changed and changed, thereby changing the fan driving voltage Vfan supplied/generated by the fan power generating unit 105.

For example, when the load of the forward power conversion line 103 is overloaded (Heavy loading), the duty cycle of the control signal (pulse width modulation signal) PW received by the control terminal of the power switch Q is relatively large, so that the fan driving voltage supplied/generated by the fan power generating unit 105 at this time is generated. It will also be relatively large. On the other hand, when the load of the forward power conversion line 103 is light loading, the duty cycle of the control signal (pulse width modulation signal) PW received by the control terminal of the power switch Q is relatively small, so that the duty cycle is relatively small. At this time, the fan driving voltage supplied/generated by the fan power generating unit 105 is also relatively small. In other words, the fan driving voltage supplied/generated by the fan power generating unit 105 changes as the source voltage (Vds) of the (N-type) power switch Q fluctuates.

Based on the above, when the power switch Q is turned on-on in response to the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209 (ie, the control signal (pulse width modulation signal) The enabling of the PW, the first power generating unit PG1 reacts with the energy on the first secondary side NS1 of the transformer T to generate a regulated power supply V1' (+5V); the second power generating unit PG2 reacts The regulated power supply V2' (+3.3V) is generated by the energy on the second secondary side NS2 of the transformer T; and the third power generating unit PG3 is responsive to the energy on the third secondary side NS3 of the transformer T. At the same time, the regulated power supply V3' (+12V) and V4' (-12V) are generated. In other words, the forward power conversion line 103 is responsive to the enable of the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209 to supply the power required by the load 20 (+5V, +3.3V). , +12V, -12V).

At the same time, the fan power generating unit 105 reacts to the transformer T The reverse voltage on the first secondary side NS1 (ie, the voltage on the terminal B) and the second power supply V2 generated by the second power generating unit PG2 that has not been regulated (ie, the voltage at the terminal C) And a fan driving voltage Vfan is generated to drive the fan 101. In other words, the fan driving voltage Vfan generated by the fan power generating unit 105 can be regarded as the accumulation of the voltage of the terminal B and the voltage of the terminal C.

In addition, since the pulse width modulation control chip 209 changes the duty cycle of the control signal (pulse width modulation signal) PW generated by the load 20 change. Therefore, when the load 20 is heavily loaded, the duty cycle of the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209 is relatively large, so that the reaction is first to third in the transformer T. The energy of the secondary side NS1~NS3 will also be relatively large. It can be seen that the fan driving voltage Vfan generated by the fan power generating unit 105 at this time increases as the voltages of the terminals B and C increase, thereby increasing the rotational speed of the fan 101.

On the other hand, when the load 20 is lightly loaded, the duty cycle of the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209 is relatively small, so that the reaction is first in the transformer T. The energy of the third secondary side NS1~NS3 will also be relatively small. It can be seen that the fan driving voltage Vfan generated by the fan power generating unit 105 at this time decreases as the voltages of the terminals B and C decrease, thereby reducing the rotational speed of the fan 101.

Obviously, the fan driving voltage Vfan required for driving the fan 101 of the present exemplary embodiment can be obtained only from the forward power conversion line 103, and the fan driving voltage Vfan is converted along with the forward power source. The load 20 of the line 103 changes (i.e., light load or heavy load) changes. As a result, The fan 101 mounted on the power supply device 10 eliminates the need to additionally design a separate control circuit corresponding to the fan, and this will reduce the overall cost of the power supply device 10.

Furthermore, when the power switch Q is turned on-off from the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209 (ie, the control signal (pulse width modulation signal) The disability of the PW, since the fan 101 can be regarded as a fixed load at this time, the transformer T can be demagnetized when the power switch Q is turned off. In this way, it is not necessary to additionally add a degaussing coil and a degaussing diode to the forward power conversion line 103, thereby further reducing the overall cost of the power supply device 10. In other words, the forward power conversion line 103 is responsive to the disable of the control signal (pulse width modulation signal) PW generated by the pulse width modulation control chip 209, and is transmitted through the fan 101 to demagnetize the transformer T.

Based on the disclosure/teaching of the above exemplary embodiments, FIG. 3 is a flow chart of a fan driving method according to an exemplary embodiment of the present invention. Referring to FIG. 3, the fan driving method of the exemplary embodiment includes: providing a power conversion circuit to supply power required by a load (step S301); and providing a part of power supplied according to the supplied power conversion line. The fan drives the voltage to drive the fan (step S303), wherein the supplied fan drive voltage is varied in response to load variations in the supplied power conversion line.

In the exemplary embodiment, the power conversion circuit provided may be A forward power conversion line. Accordingly, the forward power conversion line can be operated in response to a PWM signal, and the duty cycle of the pulse width modulation signal is reflected in the load variation of the forward power conversion line ( That is, light load or heavy load) changes to change the supplied fan drive voltage. Wherein, when the load of the forward power conversion line is heavy, the duty cycle of the pulse width modulation signal is relatively large, and the provided fan driving voltage is relatively large; conversely, when the forward power conversion line is When the load is light load, the duty cycle of the pulse width modulation signal is relatively small, and the supplied fan driving voltage is relatively small.

On the other hand, the provided (forward) power conversion line can supply the power required by the load in response to the enable of the pulse width modulation signal. In addition, the provided (forward) power conversion circuit can be demagnetized by a fan through the fan in response to the disable of the pulse width modulation signal.

In summary, the power supply device of the present invention is based on a forward architecture, and the fan driving voltage required for driving the fan can be obtained only from the forward power conversion line. The fan drive voltage will again change as the load of the forward power conversion line changes (ie, light load or heavy load). In this way, there is no need to additionally design an independent and corresponding control circuit to drive the fan installed in the power supply device, and this will reduce the overall cost of the power supply device. On the other hand, since the fan can be regarded as a fixed load, the transformer can be demagnetized when the power switch is turned off.

Although the invention has been disclosed above by way of example, it is not intended to be limiting The scope of the present invention is defined by the scope of the appended claims, and the scope of the invention is defined by the scope of the appended claims. Prevail. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

10‧‧‧Power supply unit

20‧‧‧ load

101‧‧‧fan

103‧‧‧ directional power conversion circuit

105‧‧‧Fan power generation unit

201~207‧‧‧Output level

209‧‧‧ Pulse width modulation control chip

PG1~PG3‧‧‧first to third power generation unit

D1~D10‧‧‧ Diode

ZD1~ZD4‧‧‧Zina diode

C1~C7‧‧‧ capacitor

L1~L4‧‧‧Inductance

T‧‧‧Transformer

Q‧‧‧Power switch

Primary side of NP‧‧‧ transformer

Secondary side of NS1~NS3‧‧‧ transformer

Vfan‧‧‧fan drive voltage

V1~V4‧‧‧first to fourth power supplies

V1’~V4’‧‧‧Power supply

VIN‧‧‧ input voltage

PW‧‧‧ control signal

B, C‧‧‧ endpoint

S301, S303‧‧‧ steps of the flowchart of the fan driving method of an exemplary embodiment of the present invention

The following drawings are a part of the specification of the invention, and illustrate the embodiments of the invention

FIG. 1 is a schematic diagram of a power supply apparatus 10 according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic diagram of an implementation of the power supply device 10 of FIG. 1.

FIG. 3 is a flow chart of a fan driving method according to an exemplary embodiment of the present invention.

101‧‧‧fan

103‧‧‧ directional power conversion circuit

105‧‧‧Fan power generation unit

201~207‧‧‧Output level

209‧‧‧ Pulse width modulation control chip

PG1~PG3‧‧‧first to third power generation unit

D1~D10‧‧‧ Diode

ZD1~ZD4‧‧‧Zina diode

C1~C7‧‧‧ capacitor

L1~L4‧‧‧Inductance

T‧‧‧Transformer

Q‧‧‧Power switch

Primary side of NP‧‧‧ transformer

Secondary side of NS1~NS3‧‧‧ transformer

Vfan‧‧‧fan drive voltage

V1~V4‧‧‧first to fourth power supplies

V1’~V4’‧‧‧Power supply

VIN‧‧‧ input voltage

PW‧‧‧ control signal

B, C‧‧‧ endpoint

Claims (27)

A power supply device includes: a fan; a forward power conversion circuit, comprising: a transformer having a primary side, a first secondary side, and a second secondary side, wherein the primary side of the different name The first end of the power switch is coupled to the same end of the primary side, the second end of the power switch is coupled to a ground potential, and the control end is configured to receive a control signal; a power generating unit coupled to the first secondary side for generating a first power source in response to the input voltage and a first turn ratio of the primary side and the first secondary side; and a second power source a generating unit coupled to the second secondary side for generating a second power source in response to the input voltage and a second turns ratio of the primary side and the second secondary side; and a fan power generating unit And coupling the first secondary side, the second power generating unit, and the fan to generate a fan driving voltage by reacting a reverse voltage of the first secondary side with the second power source, thereby driving the fan Fan, wherein the fan drive voltage And a reverse voltage corresponding to the variation of the power of the second regulator has not been changed. The power supply device of claim 1, wherein the first power generating unit comprises: a first diode, the anode of which is coupled to the opposite end of the first secondary side; a second diode having an anode coupled to the same end of the first secondary side and a cathode coupled to the cathode of the first diode; a first Zener diode having an anode coupled thereto a first end of the same name, and a cathode coupled to the cathode of the first diode; a first inductor having a first end coupled to the cathode of the first diode and a second end a first capacitor is coupled to the first end of the first inductor, and a second end is coupled to the same end of the first secondary side, wherein the first end is coupled to the second end of the first inductor The voltage on the different end of the first secondary side is the reverse voltage. The power supply device of claim 2, wherein the first power generating unit further comprises: a first output stage coupled to the first capacitor for regulating the first power source, thereby A first regulated power supply is output. The power supply device of claim 3, wherein the first regulated power supply is +5V. The power supply device of claim 3, wherein the second power generating unit comprises: a third diode having an anode coupled to the second end of the second name; a fourth diode An anode is coupled to the same end of the second secondary side, and a cathode is coupled to the cathode of the third diode; a second Zener diode having an anode coupled to the second secondary side a cathode of the same name, and a cathode coupled to the cathode of the third diode; a second inductor having a first end coupled to the cathode of the third diode The second end is configured to generate and output the second power source; and a second end is coupled to the second end of the second inductor, and the second end is coupled to the second second side The same name end. The power supply device of claim 5, wherein the second power generating unit further comprises: a second output stage coupled to the second capacitor for regulating the second power source, thereby A second regulated power supply is output. The power supply device of claim 6, wherein the second regulated power supply is +3.3V. The power supply device of claim 6, wherein the first and the second inductance are coupled to each other. The power supply device of claim 8, wherein the fan power generating unit comprises: a fifth diode having a cathode coupled to the different end of the first secondary side; and a third capacitor One end is coupled to the anode of the fifth diode, and the second end is coupled to the ground potential; and a fourth capacitor having a first end coupled to the anode of the fifth diode, and The two ends are coupled to the first end of the second capacitor, wherein a voltage across the fourth capacitor is the fan driving voltage. The power supply device of claim 9, wherein the transformer further has a third secondary side, and the forward power conversion circuit further comprises: a third power generating unit coupled to the third Secondary side, for reaction And generating a third power source and a fourth power source at the input voltage and a third turn ratio of the primary side and the third secondary side. The power supply device of claim 10, wherein the third power generating unit comprises: a sixth diode, the anode of which is coupled to the opposite end of the third secondary side; and a seventh diode An anode is coupled to the same end of the third secondary side, and a cathode is coupled to the cathode of the sixth diode; an eighth diode having an anode coupled to the opposite end of the third secondary side The cathode is coupled to the cathode of the sixth diode; the ninth diode has an anode coupled to the same end of the third secondary side, and a cathode coupled to the sixth diode a cathode; a third Zener diode having an anode coupled to the opposite end of the third secondary side and a cathode coupled to the cathode of the sixth diode; a fourth Zener diode The cathode is coupled to the cathode of the hexa diode; a fifth capacitor has a first end coupled to the anode of the fourth Zener diode, and a second end coupled to the same end of the third secondary side a third inductor having a first end coupled to the cathode of the sixth diode and a second end for generating and outputting the third power source; a sixth capacitor One end is coupled to the second end of the third inductor, and the second end is coupled to the third end of the same name end; a twelfth pole body, the anode is used to generate and output the fourth power source; a fourth inductor having a first end coupled to the cathode of the twelfth body; and a seventh capacitor having a first end coupled to the second end of the fourth inductor The second end is coupled to the anode of the twelfth polar body. The power supply device of claim 11, wherein the third power generating unit further includes: a third output stage coupled to the sixth capacitor for regulating the third power source, thereby And outputting a third regulated power supply; and a fourth output stage coupled to the seventh capacitor for regulating the fourth power supply to output a fourth regulated power supply. The power supply device of claim 12, wherein the third regulated power supply is +12V, and the fourth regulated power supply is -12V. The power supply device of claim 11, wherein the first and the third inductor are coupled to each other, and the third and the fourth inductor are coupled to each other. The power supply device of claim 1, wherein the control signal is a pulse width modulation signal. The power supply device of claim 15, wherein one of the duty cycles of the pulse width modulation signal changes in response to the load variation of the forward power conversion line, thereby changing the fan driving voltage. The power supply device of claim 16, wherein when the load of the forward power conversion line is a heavy load, the duty cycle of the pulse width modulation signal is relatively large, and the fan is The driving voltage is relatively large. The power supply device of claim 16, wherein when the load of the forward power conversion line is a light load, the duty cycle of the pulse width modulation signal is relatively small, and the fan Drive voltage phase To be smaller. The power supply device of claim 16, wherein the forward power conversion circuit further comprises: a pulse width modulation control chip coupled to the power switch for reacting to a power supply requirement of the load The pulse width modulation signal is generated, and the duty cycle of the pulse width modulation signal is adjusted in response to the load change. A power supply device includes: a fan; a power conversion circuit for supplying power required by a load; and a fan power generating unit coupled between the fan and the power conversion line for reacting A portion of the power supplied by the power conversion line provides a fan drive voltage to drive the fan, wherein the fan drive voltage changes in response to a reverse voltage in the power conversion line and a change in a power supply that has not been regulated. The power supply device of claim 20, wherein the power conversion circuit comprises a forward power conversion circuit, and the forward power conversion circuit operates in response to a pulse width modulation signal, and The one duty cycle of the pulse width modulation signal changes in response to the load variation of the forward power conversion line, thereby changing the fan driving voltage. The power supply device of claim 21, wherein: when the load of the forward power conversion line is a heavy load, the duty cycle of the pulse width modulation signal is relatively large, and the The fan drive voltage is relatively large; When the load of the forward power conversion line is a light load, the duty cycle of the pulse width modulation signal is relatively small, and the fan driving voltage is relatively small. The power supply device of claim 21, wherein: the forward power conversion line is responsive to the enabling of the pulse width modulation signal to supply power required by the load; and the forward power conversion The line reacts to the disablement of the pulse width modulation signal to degauss a transformer therein. A fan driving method includes: providing a power conversion line to supply power required by a load; and providing a fan driving voltage to drive a fan according to a part of the power supplied by the power conversion line, wherein the fan driving voltage response The reverse voltage in the power conversion line and the change in a power source that has not been regulated. The fan driving method of claim 24, wherein the power conversion circuit comprises a forward power conversion circuit, and the forward power conversion circuit operates in response to a pulse width modulation signal, and The one duty cycle of the pulse width modulation signal changes in response to the load variation of the forward power conversion line, thereby changing the fan driving voltage. The fan driving method of claim 25, wherein: when the load of the forward power conversion line is a heavy load, the duty cycle of the pulse width modulation signal is relatively large, and the Fan drive voltage When the load of the forward power conversion line is a light load, the duty cycle of the pulse width modulation signal is relatively small, and the fan driving voltage is relatively small. The fan driving method of claim 25, wherein: the forward power conversion line is responsive to the enabling of the pulse width modulation signal to supply power required by the load; and the forward power conversion The line reacts to the disablement of the pulse width modulation signal to degauss a transformer therein.