Low-cost voltage-adjustable control circuit

Abstract

The utility model discloses a low-cost voltage-adjustable control circuit, which mainly solves the problem that the speed regulation control cost of the existing fan is high. The circuit comprises a fan power supply input filter circuit, an amplifier tube connected with the fan power supply input filter circuit, and a multi-gear rotating speed control circuit connected with the amplifier tube, and the multi-gear rotating speed control circuit is connected with an external fan CPU (Central Processing Unit). Through the above design, the circuit design of discrete components such as low-cost common triodes, voltage-regulator tubes, resistors, capacitors and the like is used, the cost is low, intelligent voltage regulation is highly reliably realized, energy is saved, the service life of a product is prolonged, and guarantee is provided for continuous high-reliability work, so that the circuit is worthy of popularization.

Description

Technical Field

[0001] The utility model belongs to the technical field of fan gear position control, in particular to a low-cost adjustable voltage control circuit. Background Art

[0002] In order to save energy and extend the service life of fans in current electronic equipment such as switches, it is necessary to control the speed of the wind speed in real time according to usage, thereby ensuring product reliability while increasing product service life and energy saving and environmental protection.

[0003] In the prior art, realizing the operation of a fan from 1 to N gears requires a specially adjustable wind speed and a dedicated fan drive and speed regulation chip, which increases the cost exponentially. Utility Model Content

[0004] The utility model aims to provide a low-cost adjustable voltage control circuit, mainly to solve the problem of high cost of existing fan speed control.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0006] A low-cost adjustable voltage control circuit includes a fan power input filter circuit, an amplifier connected to the fan power input filter circuit, and a multi-speed speed control circuit connected to the amplifier; wherein the multi-speed speed control circuit is connected to an external fan CPU.

[0007] Furthermore, in the present invention, the multi-gear control circuit includes a second-gear speed control circuit and a third-gear speed control circuit; wherein the second-gear speed control circuit and the third-gear speed control circuit are both connected to an external fan CPU.

[0008] Furthermore, in the utility model, the fan power input filter circuit includes a connector J1 connected to the fan, a capacitor C1 with one end connected to the positive electrode of the connector J1 and the other end grounded, a capacitor C2 with one end connected to the positive electrode of the connector J1 and the other end grounded, a magnetic bead FB1 with one end connected to the positive electrode of the connector J1, a capacitor C3 with one end connected to the other end of the magnetic bead FB1 and the other end grounded, and a capacitor C4 with one end connected to the input power supply and the other end grounded; wherein, the common end of the magnetic bead FB1 and the capacitor C3 is connected to the emitter of the amplifier tube; and the non-grounded end of the capacitor C4 is connected to the collector of the amplifier tube.

[0009] Furthermore, in the present invention, the amplifier tube adopts an NPN transistor Q1 with a model of MMBT2222A.

[0010] Furthermore, in the utility model, the second-gear speed control circuit includes a bias resistor R1 connected between the base and collector of the transistor Q1, a voltage-stabilizing diode D1 whose cathode is connected to the base of the transistor Q1, an NPN transistor Q2 of model MMBT3904 whose collector is connected to the anode of the voltage-stabilizing diode D1 and whose emitter is grounded, a resistor R5 whose one end is connected to the base of the transistor Q2, and a resistor R2 whose one end is connected to the other end of the resistor R5 and whose other end is grounded; wherein the common end of the resistor R2 and the resistor R5 is connected to the fan CPU.

[0011] Furthermore, in the utility model, the three-speed speed control circuit includes a voltage-stabilizing diode D2 whose cathode is connected to the base of the transistor Q1, a resistor R3 connected in parallel to both ends of the voltage-stabilizing diode D2, an NPN transistor Q3 of model MMBT3904 whose collector is connected to the anode of the voltage-stabilizing diode D2 and whose emitter is grounded, a resistor R6 whose one end is connected to the base of the transistor Q3, and a resistor R4 whose one end is connected to the other end of the resistor R6 and whose other end is grounded; wherein the common end of the resistor R4 and the resistor R6 is connected to the fan CPU.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] The utility model uses a low-cost common fan and a discrete component combination circuit to realize the operation of the fan from 1 to N gears. In addition, the circuit structure is simple and the control cost is low, which greatly reduces the control cost of the fan wind speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a three-speed wind speed control circuit diagram in an embodiment of the utility model. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The present invention includes but is not limited to the following embodiments.

[0016] like Figure 1As shown, the utility model discloses a low-cost adjustable voltage control circuit. This embodiment takes a common fan adjustment three-speed switch as an example: J1 is a connector for connecting the fan, and the magnetic bead FB1 and capacitors C1-C4 are fan power input filter circuits. Q1 MMBT2222A is an NPN transistor used as an amplifier. Q2 NPI transistor MMBT3904 is used as a switch tube and Schottky voltage regulator diode D1 (this example takes a 10V voltage regulator tube as an example) is used as the second speed voltage regulation control application of the fan. R1 is the base bias resistor of Q1 and also the collector bias resistor of Q2. R2 and R5 are the base bias current limiting resistors of Q2. Q3 is an NPN transistor MMBT3904 as a switch tube and Schottky voltage regulator diode D2 (8.2V voltage regulator is used as an example in this example) as the third gear application of the fan speed voltage regulation control. R1 is the base bias resistor of Q1 and the collector bias resistor of Q3. R4 and R6 are the base bias current limiting resistors of Q3. GPIO1_FAN10V_CTRL and GPIO2_FAN8.2V_CTRL are connected to the ordinary GPIO1 and GPIO2 of the CPU. When GPIO1 and GPIO2 both output a low level, Q2 and Q3 are both cut off, Q1 is turned on, and the power supply voltage of fan J1 is close to 12V. At this time, the fan is running at high speed in the first gear. When GPIO1 outputs a high level and GPIO2 is a low level, Q2 is turned on, Q3 is cut off, and Q1 is turned on. At the same time, the E-pole voltage of Q1 is clamped to about 10V of the voltage regulator tube of D1, which is the second gear operation of the fan. When GPIO1 outputs a low level and GPIO2 outputs a high level, Q2 is turned off, Q3 is turned on, Q1 is turned on, and at the same time, the voltage of the E pole of Q1 is clamped at about 8V of the voltage regulator tube D2, which is the third gear of the fan. R3 is connected in parallel with D2. If R3 is a 0R resistor, the fan can be stopped when GPIO1 outputs a low level and GPIO2 outputs a high level. The truth table of the circuit is shown in Table 1.

[0017] Table 1 Fan status truth table

[0018]

[0019] Although this example takes the fan with three gears as an example, if more adjustment gears are needed, only one more level of this switch voltage regulation circuit is needed. At the same time, the models and parameters of each component can be selected and adjusted according to the power and other conditions. At the same time, this circuit is suitable for various applications of voltage regulation and is not limited to fan speed control.

[0020] Through the above design, the utility model uses low-cost ordinary triodes and voltage regulators, resistors, capacitors and other discrete components in the circuit design. While having low cost, it realizes intelligent voltage regulation with high reliability to achieve energy saving and extend the life of the product, providing a guarantee for continuous high-reliability operation, and is therefore worthy of promotion.

[0021] The above embodiment is only one of the preferred implementation modes of the present utility model and should not be used to limit the protection scope of the present utility model. Any changes or modifications that are made to the main design concept and spirit of the present utility model without any substantive significance, as long as the technical problems solved are still consistent with the present utility model, should be included in the protection scope of the present utility model.

Claims

1. A low-cost adjustable voltage control circuit, characterized in that: It includes a fan power input filter circuit, an amplifier connected to the fan power input filter circuit, and a multi-speed speed control circuit connected to the amplifier; wherein the multi-speed speed control circuit is connected to an external fan CPU.

2. A low-cost adjustable voltage control circuit according to claim 1, characterized in that: The multi-gear speed control circuit includes a second-gear speed control circuit and a third-gear speed control circuit; wherein the second-gear speed control circuit and the third-gear speed control circuit are both connected to an external fan CPU.

3. A low-cost adjustable voltage control circuit according to claim 2, characterized in that: The fan power input filter circuit includes a connector J1 connected to the fan, a capacitor C1 with one end connected to the positive electrode of the connector J1 and the other end grounded, a capacitor C2 with one end connected to the positive electrode of the connector J1 and the other end grounded, a magnetic bead FB1 with one end connected to the positive electrode of the connector J1, a capacitor C3 with one end connected to the other end of the magnetic bead FB1 and the other end grounded, and a capacitor C4 with one end connected to the input power supply and the other end grounded; wherein the common end of the magnetic bead FB1 and the capacitor C3 is connected to the emitter of the amplifier tube; and the non-grounded end of the capacitor C4 is connected to the collector of the amplifier tube.

4. A low-cost adjustable voltage control circuit according to claim 3, characterized in that: The amplifier tube adopts an NPN transistor Q1 with a model of MMBT2222A.

5. A low-cost adjustable voltage control circuit according to claim 4, characterized in that: The second-gear speed control circuit includes a bias resistor R1 connected between the base and collector of the transistor Q1, a voltage-stabilizing diode D1 whose cathode is connected to the base of the transistor Q1, an NPN transistor Q2 of model MMBT3904 whose collector is connected to the anode of the voltage-stabilizing diode D1 and whose emitter is grounded, a resistor R5 whose one end is connected to the base of the transistor Q2, and a resistor R2 whose one end is connected to the other end of the resistor R5 and whose other end is grounded; wherein the common end of the resistor R2 and the resistor R5 is connected to the fan CPU.

6. A low-cost adjustable voltage control circuit according to claim 5, characterized in that: The three-speed speed control circuit includes a voltage-stabilizing diode D2 whose cathode is connected to the base of the transistor Q1, a resistor R3 connected in parallel to both ends of the voltage-stabilizing diode D2, an NPN transistor Q3 of model MMBT3904 whose collector is connected to the anode of the voltage-stabilizing diode D2 and whose emitter is grounded, a resistor R6 whose one end is connected to the base of the transistor Q3, and a resistor R4 whose one end is connected to the other end of the resistor R6 and whose other end is grounded; wherein the common end of the resistor R4 and the resistor R6 is connected to the fan CPU.

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