CN218971474U - Step-down fan speed regulating circuit - Google Patents
Step-down fan speed regulating circuit Download PDFInfo
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- CN218971474U CN218971474U CN202223052703.8U CN202223052703U CN218971474U CN 218971474 U CN218971474 U CN 218971474U CN 202223052703 U CN202223052703 U CN 202223052703U CN 218971474 U CN218971474 U CN 218971474U
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Abstract
The utility model discloses a speed regulating circuit of a step-down fan, which comprises a triode push-pull module, an MOS tube and a step-down output module; the triode push-pull module is connected with the grid electrode of the MOS tube, the triode push-pull module controls the grid voltage of the MOS tube based on the input control signal, and the MOS tube is controlled to be turned on and off according to the control signal, so that a voltage reduction chip is replaced by the triode push-pull module, the voltage reduction chip can be omitted on a circuit, a voltage reduction control circuit can be simply built only by utilizing a triode, the fan rotating speed can be reasonably regulated according to the size of a load, and the effects of saving energy consumption and improving the use efficiency are achieved.
Description
Technical Field
The utility model relates to the technical field of electronic circuits, in particular to a speed regulating circuit of a step-down fan.
Background
Currently, for fans applied to air-cooled switching power supplies, a BUCK (BUCK) chip is generally used to control the fans. Although the step-down chip is adopted to realize the regulation of the rotating speed of the fan, the chip energy consumption is larger, the requirement of low energy consumption cannot be met, and the cost is higher.
Disclosure of Invention
The technical problems to be solved by the utility model are as follows: the step-down fan speed regulating circuit reduces the energy consumption of the fan.
In order to solve the technical problems, the utility model adopts the following technical scheme:
a speed regulating circuit of a step-down fan comprises a triode push-pull module, an MOS tube and a step-down output module;
the input end of the triode push-pull module is used for inputting a control signal; the output end of the triode push-pull module is connected with the grid electrode of the MOS tube;
the source electrode of the MOS tube is connected with a first grounding point; the drain electrode of the MOS tube is connected with the control input end of the buck output module;
the positive electrode output end and the negative electrode output end of the voltage reduction output module are respectively connected with a fan; the positive electrode output end of the step-down output module is also used for inputting a power supply; the negative electrode output end of the voltage reduction output module is also connected with a second grounding point.
Further, the triode push-pull module comprises a first-stage control group, a second-stage control group and a third-stage control group;
the power input end of the primary control group, the power input end of the secondary control group and the power input end of the tertiary control group are respectively connected with the positive output end of the voltage reduction output module;
the control input end of the primary control group is used for inputting control signals, and the output end of the primary control group is connected with the control input end of the secondary control group;
the output end of the secondary control group is connected with the control input end of the tertiary control group; and the output end of the three-stage control group is connected with the grid electrode of the MOS tube.
Further, the primary control group comprises a first triode, a first resistor, a second resistor and a third resistor;
one end of the first resistor is connected with one end of the second resistor and the base electrode of the first triode respectively; the other end of the first resistor is used for inputting a control signal;
the collector electrode of the first triode is respectively connected with one end of the third resistor and the control input end of the second-level control group; the other end of the third resistor is connected with the positive electrode output end of the step-down output module;
and the emitter of the first triode is connected with the other end of the second resistor and is connected with the first grounding point.
Further, the secondary control group comprises a second triode and a fourth resistor;
the base electrode of the second triode is connected with the output end of the primary control group;
the collector electrode of the second triode is respectively connected with one end of the fourth resistor and the control input end of the three-stage control group; the other end of the fourth resistor is connected with the positive electrode output end of the step-down output module;
and an emitter of the second triode is connected with the first grounding point.
Further, the three-stage control group comprises a third triode, a fourth triode and a fifth resistor;
one end of the fifth resistor is connected with the positive electrode output end of the step-down output module; the other end of the fifth resistor is connected with the collector electrode of the third triode;
the base electrode of the third triode and the base electrode of the fourth triode are respectively connected with the output end of the second-level control group;
the emitter of the third triode is respectively connected with the emitter of the fourth triode and the grid electrode of the MOS tube;
and the collector electrode of the fourth triode is connected with the first grounding point.
Further, the three-stage control group further comprises a sixth resistor and a seventh resistor;
one end of the sixth resistor is respectively connected with one end of the seventh resistor, the emitter of the third triode and the emitter of the fourth triode;
the other end of the sixth resistor is connected with the other end of the seventh resistor and the grid electrode of the MOS tube respectively.
Further, the buck output module comprises a first capacitor, a first inductor and a first diode;
the anode of the first capacitor and the cathode of the first diode are used for inputting a power supply;
the negative electrode of the first capacitor is connected with one end of the first inductor and is connected with the second grounding point;
the other end of the first inductor is connected with the anode of the first diode and the drain electrode of the MOS tube respectively.
The utility model has the beneficial effects that: the triode push-pull module is connected with the grid electrode of the MOS tube, the triode push-pull module controls the grid voltage of the MOS tube based on the input control signal, and the MOS tube is controlled to be turned on and off according to the control signal, so that a voltage reduction chip is replaced by the triode push-pull module, the voltage reduction chip can be omitted on a circuit, a voltage reduction control circuit can be simply built only by utilizing a triode, the fan rotating speed can be reasonably regulated according to the size of a load, and the effects of saving energy consumption and improving the use efficiency are achieved.
Drawings
FIG. 1 is a schematic diagram of a step-down fan speed regulation circuit in an embodiment of the utility model;
FIG. 2 is a timing control diagram of a step-down fan speed regulation circuit according to an embodiment of the present utility model;
description of the reference numerals:
1. a triode push-pull module; 2. a step-down output module; gnd_fan, first ground point; GND, second ground point; FANVCC, power supply; fan_con, control signal; c1, a first capacitor; l1, a first inductor; d1, a first diode; r1, a first resistor; r2, a second resistor; r3, a third resistor; r4, a fourth resistor; r5, a fifth resistor; r6, a sixth resistor; r7, a seventh resistor; q1, a first triode; q2, a second triode; q3, a third triode; q4, a fourth triode; q5, MOS tube.
Detailed Description
In order to describe the technical contents, the achieved objects and effects of the present utility model in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.
Referring to fig. 1, a step-down fan speed regulating circuit includes a triode push-pull module, a MOS transistor and a step-down output module;
the input end of the triode push-pull module is used for inputting a control signal; the output end of the triode push-pull module is connected with the grid electrode of the MOS tube;
the source electrode of the MOS tube is connected with a first grounding point; the drain electrode of the MOS tube is connected with the control input end of the buck output module;
the positive electrode output end and the negative electrode output end of the voltage reduction output module are respectively connected with a fan; the positive electrode output end of the step-down output module is also used for inputting a power supply; the negative electrode output end of the voltage reduction output module is also connected with a second grounding point.
From the above description, the beneficial effects of the utility model are as follows: the triode push-pull module is connected with the grid electrode of the MOS tube, the triode push-pull module controls the grid voltage of the MOS tube based on the input control signal, and the MOS tube is controlled to be turned on and off according to the control signal, so that a voltage reduction chip is replaced by the triode push-pull module, the voltage reduction chip can be omitted on a circuit, a voltage reduction control circuit can be simply built only by utilizing a triode, the fan rotating speed can be reasonably regulated according to the size of a load, and the effects of saving energy consumption and improving the use efficiency are achieved.
Further, the triode push-pull module comprises a first-stage control group, a second-stage control group and a third-stage control group;
the power input end of the primary control group, the power input end of the secondary control group and the power input end of the tertiary control group are respectively connected with the positive output end of the voltage reduction output module;
the control input end of the primary control group is used for inputting control signals, and the output end of the primary control group is connected with the control input end of the secondary control group;
the output end of the secondary control group is connected with the control input end of the tertiary control group; and the output end of the three-stage control group is connected with the grid electrode of the MOS tube.
The triode push-pull module is composed of a primary control group, a secondary control group and a tertiary control group, and the MOS tube is controlled by using an input control signal in a multistage connection mode, so that the signal stability is improved.
Further, the primary control group comprises a first triode, a first resistor, a second resistor and a third resistor;
one end of the first resistor is connected with one end of the second resistor and the base electrode of the first triode respectively; the other end of the first resistor is used for inputting a control signal;
the collector electrode of the first triode is respectively connected with one end of the third resistor and the control input end of the second-level control group; the other end of the third resistor is connected with the positive electrode output end of the step-down output module;
and the emitter of the first triode is connected with the other end of the second resistor and is connected with the first grounding point.
As can be seen from the above description, the voltage input to the first triode is controlled by the first resistor and the second resistor, and the current input to the first triode is controlled by the third resistor, so that the working stability of the first triode is improved, and the effective control output is realized.
Further, the secondary control group comprises a second triode and a fourth resistor;
the base electrode of the second triode is connected with the output end of the primary control group;
the collector electrode of the second triode is respectively connected with one end of the fourth resistor and the control input end of the three-stage control group; the other end of the fourth resistor is connected with the positive electrode output end of the step-down output module;
and an emitter of the second triode is connected with the first grounding point.
From the above description, the second triode and the fourth resistor form a second control group, so that the signal output by the first control group is optimized, and the control effect on the MOS tube is improved.
Further, the three-stage control group comprises a third triode, a fourth triode and a fifth resistor;
one end of the fifth resistor is connected with the positive electrode output end of the step-down output module; the other end of the fifth resistor is connected with the collector electrode of the third triode;
the base electrode of the third triode and the base electrode of the fourth triode are respectively connected with the output end of the second-level control group;
the emitter of the third triode is respectively connected with the emitter of the fourth triode and the grid electrode of the MOS tube;
and the collector electrode of the fourth triode is connected with the first grounding point.
From the above description, the push-pull circuit is formed by the third triode and the fourth triode, so that not only is the control on the MOS tube realized, but also the circuit consumption is reduced.
Further, the three-stage control group further comprises a sixth resistor and a seventh resistor;
one end of the sixth resistor is respectively connected with one end of the seventh resistor, the emitter of the third triode and the emitter of the fourth triode;
the other end of the sixth resistor is connected with the other end of the seventh resistor and the grid electrode of the MOS tube respectively.
From the above description, the output voltage can be controlled within the range adapted to the MOS transistor by the sixth resistor and the seventh resistor connected in parallel to the output end of the three-stage control group, so as to effectively control the MOS transistor.
Further, the buck output module comprises a first capacitor, a first inductor and a first diode;
the anode of the first capacitor and the cathode of the first diode are used for inputting a power supply;
the negative electrode of the first capacitor is connected with one end of the first inductor and is connected with the second grounding point;
the other end of the first inductor is connected with the anode of the first diode and the drain electrode of the MOS tube respectively.
As can be seen from the above description, the BUCK circuit is formed by the first capacitor, the first inductor, the first diode, the MOS transistor and the triode push-pull module, so as to realize the BUCK control of the input voltage according to the input control signal, thereby realizing the fan rotation speed control.
The step-down fan speed regulating circuit of the embodiment can be suitable for an application scene of a speed regulating fan, can realize fan speed control and reduce energy consumption, and is described by a specific embodiment:
example 1
Referring to fig. 1, a step-down fan speed regulating circuit includes a triode push-pull module 1, a MOS transistor Q5 and a step-down output module 2; the input end of the triode push-pull module 1 is used for inputting a control signal FAN_CON; the output end of the triode push-pull module 1 is connected with the grid electrode of the MOS tube Q5; the source electrode of the MOS tube Q5 is connected with a first grounding point GND_FAN; the drain electrode of the MOS tube Q5 is connected with the control input end of the buck output module 2; the positive electrode output end and the negative electrode output end of the step-down output module 2 are respectively connected with a fan; the positive electrode output end of the step-down output module 2 is also used for inputting a power supply FANVCC; the negative electrode output end of the step-down output module 2 is also connected with a second grounding point GND;
the buck output module 2 comprises a first capacitor C1, a first inductor L1 and a first diode D1; the anode of the first capacitor C1 and the cathode of the first diode D1 are used for inputting a power source FANVCC; the negative electrode of the first capacitor C1 is connected with one end of the first inductor L1 and is connected with the second grounding point GND; the other end of the first inductor L1 is connected with the anode of the first diode D1 and the drain electrode of the MOS tube Q5 respectively; the input voltage of the voltage reduction module is the voltage difference between the power supply FANVCC end and the second grounding point GND, and the output voltage of the voltage reduction module is the voltage difference between the power supply FANVCC end and the first grounding point GND_FAN; the level of the first grounding point GND_FAN is greater than or equal to the level of the second grounding point GND, and the potential difference value between the first grounding point GND and the second grounding point GND is equal to the voltage at two ends of the first inductor L1; when the duty ratio of the buck output module 2 is 100%, the level of the first ground gnd_fan is equal to the level of the second ground GND; when the duty ratio of the step-down output module 2 is less than 100%, the level of the first ground point gnd_fan is greater than the level of the second ground point GND;
in an alternative embodiment, the triode push-pull module 1 comprises a primary control group, a secondary control group and a tertiary control group; the primary control group comprises a first triode Q1, a first resistor R1, a second resistor R2 and a third resistor R3; one end of the first resistor R1 is respectively connected with one end of the second resistor R2 and the base electrode of the first triode Q1; the other end of the first resistor R1 is used for inputting a control signal FAN_CON; the collector electrode of the first triode Q1 is respectively connected with one end of the third resistor R3 and the base electrode of the second triode Q2; the other end of the third resistor R3 is connected with the positive electrode output end of the step-down output module 2; the emitter of the first triode Q1 is connected with the other end of the second resistor R2 and is connected with the first grounding point GND_FAN;
the second-stage control group comprises a second triode Q2 and a fourth resistor R4; the collector of the second triode Q2 is respectively connected with one end of the fourth resistor R4, the base of the third triode Q3 and the base of the fourth triode Q4; the other end of the fourth resistor R4 is connected with the positive electrode output end of the step-down output module 2; the emitter of the second triode Q2 is connected with the first grounding point GND_FAN;
the three-level control group comprises a third triode Q3, a fourth triode Q4 and a fifth resistor R5; one end of the fifth resistor R5 is connected with the positive electrode output end of the step-down output module 2; the other end of the fifth resistor R5 is connected with the collector electrode of the third triode Q3; the emitter of the third triode Q3 is respectively connected with the emitter of the fourth triode Q4 and the grid electrode of the MOS tube Q5; the collector of the fourth triode Q4 is connected with the first grounding point GND_FAN;
the three-stage control group further comprises a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 is connected to one end of the seventh resistor R7, the emitter of the third triode Q3, and the emitter of the fourth triode Q4, respectively; the other end of the sixth resistor R6 is connected with the other end of the seventh resistor R7 and the grid electrode of the MOS tube Q5 respectively; the first triode Q1, the second triode Q2 and the third triode Q3 are NPN triodes, and the fourth triode Q4 is a PNP triode;
the specific principle of the step-down fan speed regulating circuit is as follows:
referring to fig. 2, when the control signal fan_con is at a high level 3.3V, the collector and the emitter of the first transistor Q1 are turned on, so that the base input of the second transistor Q2 is at a low level, i.e., the collector and the emitter of the second transistor Q2 are not turned on, and the base of the third transistor Q3 and the base of the fourth transistor Q4 are input at a high level, i.e., the collector and the emitter of the third transistor Q3 are turned on, and a high level is output to the gate of the MOS transistor Q5, so that the MOS transistor Q5 is turned on, the input voltage of the step-down output module 2 electrically stores energy in the first inductor L1 and the first capacitor C1, and simultaneously provides current to the FAN;
when the control signal fan_con is at a low level, the first triode Q1 is not turned on, so that the second triode Q2 is turned on, the third triode Q3 is not turned on, the fourth triode Q4 is turned on, the low level is output to the grid of the MOS tube Q5, so that the MOS tube Q5 is turned off, the input voltage of the buck output module 2 is cut off by the MOS tube Q5, the first inductor L1 and the first capacitor C1 cannot be charged, after the MOS tube Q5 is turned off, the first inductor L1 stores electric energy, the current of the first inductor cannot be suddenly changed, the inductor current charges the first capacitor C1 through a freewheeling diode, namely a first diode D1, simultaneously provides current for a FAN, keeps the FAN to rotate, and keeps the FAN to repeatedly work every cycle, and keeps the FAN voltage to stably rotate;
namely, the on-off time sequence of the MOS transistor Q5 is controlled by the control signal FAN_CON, and the voltage on a FAN end, namely the first capacitor C1, can be adjusted by changing the duty ratio of the control signal FAN_CON, so that the FAN speed regulation is realized; the linear speed regulation of the FAN from never rotating to full rotating can be realized by reasonably controlling the duty ratio of the square wave signal (namely the control signal FAN_CON);
in a specific example, if the output load of the switching power supply is at most 20A, when the load is above 12A, the duty ratio of the control signal fan_con is set to 100% by the singlechip, so that the step-down output module 2 supplies the FAN with the voltage=fanvcc=100% =12v, and the FAN rotates fully at this time; when the load is below 12A, the duty ratio of the control signal fan_con is set to 50% by the singlechip, so that the step-down output module 2 is a FAN supply voltage=fanvcc=50% = 6v, and the FAN turns slightly at this time.
The foregoing description is only illustrative of the present utility model and is not intended to limit the scope of the utility model, and all equivalent changes made by the specification and drawings of the present utility model, or direct or indirect application in the relevant art, are included in the scope of the present utility model.
Claims (7)
1. The step-down fan speed regulating circuit is characterized by comprising a triode push-pull module, an MOS tube and a step-down output module;
the input end of the triode push-pull module is used for inputting a control signal; the output end of the triode push-pull module is connected with the grid electrode of the MOS tube;
the source electrode of the MOS tube is connected with a first grounding point; the drain electrode of the MOS tube is connected with the control input end of the buck output module;
the positive electrode output end and the negative electrode output end of the voltage reduction output module are respectively connected with a fan; the positive electrode output end of the step-down output module is also used for inputting a power supply; the negative electrode output end of the voltage reduction output module is also connected with a second grounding point.
2. The step-down fan speed regulation circuit of claim 1, wherein the triode push-pull module comprises a primary control group, a secondary control group and a tertiary control group;
the power input end of the primary control group, the power input end of the secondary control group and the power input end of the tertiary control group are respectively connected with the positive output end of the voltage reduction output module;
the control input end of the primary control group is used for inputting control signals, and the output end of the primary control group is connected with the control input end of the secondary control group;
the output end of the secondary control group is connected with the control input end of the tertiary control group; and the output end of the three-stage control group is connected with the grid electrode of the MOS tube.
3. The step-down fan speed regulation circuit of claim 2, wherein the primary control group comprises a first triode, a first resistor, a second resistor and a third resistor;
one end of the first resistor is connected with one end of the second resistor and the base electrode of the first triode respectively; the other end of the first resistor is used for inputting a control signal;
the collector electrode of the first triode is respectively connected with one end of the third resistor and the control input end of the second-level control group; the other end of the third resistor is connected with the positive electrode output end of the step-down output module;
and the emitter of the first triode is connected with the other end of the second resistor and is connected with the first grounding point.
4. The step-down fan speed regulation circuit of claim 2 wherein the secondary control group includes a second triode and a fourth resistor;
the base electrode of the second triode is connected with the output end of the primary control group;
the collector electrode of the second triode is respectively connected with one end of the fourth resistor and the control input end of the three-stage control group; the other end of the fourth resistor is connected with the positive electrode output end of the step-down output module;
and an emitter of the second triode is connected with the first grounding point.
5. The step-down fan speed regulation circuit of claim 2 wherein the three stage control group includes a third transistor, a fourth transistor and a fifth resistor;
one end of the fifth resistor is connected with the positive electrode output end of the step-down output module; the other end of the fifth resistor is connected with the collector electrode of the third triode;
the base electrode of the third triode and the base electrode of the fourth triode are respectively connected with the output end of the second-level control group;
the emitter of the third triode is respectively connected with the emitter of the fourth triode and the grid electrode of the MOS tube;
and the collector electrode of the fourth triode is connected with the first grounding point.
6. The step-down fan speed regulation circuit of claim 5 wherein the three stage control group further comprises a sixth resistor and a seventh resistor;
one end of the sixth resistor is respectively connected with one end of the seventh resistor, the emitter of the third triode and the emitter of the fourth triode;
the other end of the sixth resistor is connected with the other end of the seventh resistor and the grid electrode of the MOS tube respectively.
7. The buck fan speed regulating circuit of claim 1 wherein the buck output module includes a first capacitor, a first inductor, and a first diode;
the anode of the first capacitor and the cathode of the first diode are used for inputting a power supply;
the negative electrode of the first capacitor is connected with one end of the first inductor and is connected with the second grounding point;
the other end of the first inductor is connected with the anode of the first diode and the drain electrode of the MOS tube respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202223052703.8U CN218971474U (en) | 2022-11-17 | 2022-11-17 | Step-down fan speed regulating circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223052703.8U CN218971474U (en) | 2022-11-17 | 2022-11-17 | Step-down fan speed regulating circuit |
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| CN218971474U true CN218971474U (en) | 2023-05-05 |
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| CN202223052703.8U Active CN218971474U (en) | 2022-11-17 | 2022-11-17 | Step-down fan speed regulating circuit |
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