CN210518108U - BUCK switch type voltage reduction circuit - Google Patents
BUCK switch type voltage reduction circuit Download PDFInfo
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- CN210518108U CN210518108U CN201921623855.4U CN201921623855U CN210518108U CN 210518108 U CN210518108 U CN 210518108U CN 201921623855 U CN201921623855 U CN 201921623855U CN 210518108 U CN210518108 U CN 210518108U
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Abstract
The utility model discloses a BUCK switch type voltage reduction circuit, which comprises a power supply, a driving module, a switch element, an inductor and a load; the positive pole of power with the positive pole of load is connected, the positive pole of power with drive module's voltage input end is connected, drive module's drive output with switching element's drive input end is connected, switching element's output with inductance one end is connected, the inductance other end with the negative pole of load is connected, the negative pole of power with switching element's voltage input end is connected. The utility model discloses a components and parts are few, simple structure, cost are reduced.
Description
Technical Field
The utility model relates to a switching power supply technical field, in particular to BUCK switch type step-down circuit.
Background
The switching circuit is an important circuit in an electronic circuit, plays a role in controlling and adjusting the voltage of a stable output end, and is usually assembled and connected by adopting a large number of components. The existing BUCK switch voltage-reducing circuit basically consists of a PWM chip and an MOS tube; the negative pole of the power supply is connected with the negative pole of the load, the positive pole of the power supply is connected with the positive pole of the load after being connected with components such as an MOS tube and an inductor in series, the negative pole of the power supply is also connected with a PWM chip, and the PWM chip drives the MOS tube through an isolation transformer and a driving circuit. However, the connection method requires many components, has complex circuit, high cost and low efficiency, and is not favorable for quality control of products.
Disclosure of Invention
To the problem that BUCK switch step-down circuit structure is complicated among the prior art, the cost is higher, the utility model provides a simple structure, BUCK switch type step-down circuit with low costs.
In order to achieve the above object, the present invention provides the following technical solutions:
a BUCK switch type voltage reduction circuit comprises a power supply, a driving module, a switch element, an inductor and a load;
the positive pole of power with the positive pole of load is connected, the positive pole of power with drive module's voltage input end is connected, drive module's drive output with switching element's drive input end is connected, switching element's output with inductance one end is connected, the inductance other end with the negative pole of load is connected, the negative pole of power with switching element's voltage input end is connected.
Preferably, the switching element is a field effect transistor.
Preferably, the driving module comprises a PWM chip U1:
the input positive pole of the power supply is respectively connected with the load output positive pole and one end of a second resistor, and the other end of the second resistor is connected with the voltage input end of U1; the grounding end of the U1 is respectively connected with one end of the first capacitor and the negative pole of the power input, and the other end of the first capacitor is connected with the positive pole of the power input;
the driving output end of the PWM chip U1 is respectively connected with one end of a third resistor and the cathode of the first diode, the other end of the third resistor is connected with the anode of the first diode in parallel and then respectively connected with the grid of the field-effect tube and one end of a ninth resistor, and the other end of the ninth resistor is connected with the source of the field-effect tube;
the current detection end of the PWM chip U1 is connected with one end of a fifth capacitor, and the other end of the fifth capacitor is connected with the base electrode of the second triode; the control end of the U1 is connected with the collector of the second triode, the emitter of the second triode is connected with one end of the fifth resistor, the other end of the fifth resistor is connected with one end of the eighth resistor, and the other end of the eighth resistor is connected with the source electrode of the field effect transistor;
the power input negative electrode is respectively connected with one end of a sixth resistor and one end of a seventh resistor, and the other end of the sixth resistor and the other end of the seventh resistor are connected in parallel and then connected with the source electrode of the field effect transistor; and the drain electrode of the field effect transistor is connected with one end of the inductor, and the other end of the inductor is connected with the negative electrode of the load.
Preferably, the driving module further comprises a voltage feedback circuit:
the load output positive electrode is connected with one end of a second resistor, the other end of the second resistor is respectively connected with one end of a third capacitor and one end of a fourth capacitor, and the other end of the third capacitor and the other end of the fourth capacitor are connected in parallel and then connected with a voltage feedback port of U1;
the voltage feedback port of the U1 is also connected with one end of a second capacitor, one end of a first resistor and the emitter of a photoelectric coupler respectively, and the other end of the second capacitor, the other end of the first resistor and the collector of the photoelectric coupler are connected in parallel and then connected with the current compensation port of the U1.
Preferably, the driving module further includes a current protection circuit:
a chip frequency setting port of U1 is respectively connected with one end of a sixth capacitor and one end of a seventh capacitor, and the other end of the seventh capacitor is connected with the negative electrode of the power input;
the other end of the sixth capacitor is connected with one end of a tenth resistor, the other end of the tenth resistor is connected with one end of an eighth capacitor, the other end of the eighth capacitor is connected with one end of a ninth capacitor, the other end of the ninth capacitor is respectively connected with a collector of the second triode and one end of a fourth resistor, and the other end of the fourth resistor is connected with a base electrode of the second triode.
To sum up, owing to adopted above-mentioned technical scheme, compare with prior art, the utility model discloses following beneficial effect has at least:
the utility model discloses a carry on the positive negative pole of load and the positive negative pole of power and alternate the connection, adjust the duty cycle of switch tube according to the voltage of output end load, current change with the photoelectric coupler, improved the reliability of circuit, reduced the complexity; and the MOS tube is directly controlled by the driving module (namely a PWM chip), so that the number of components in the circuit is reduced, namely the cost is reduced.
Description of the drawings:
fig. 1 is a diagram illustrating a novel BUCK switching mode step-down circuit according to an exemplary embodiment of the present invention.
Fig. 2 is a schematic diagram of a novel BUCK switching mode step-down circuit according to an exemplary embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples and specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter is limited to the following embodiments, and all the technologies realized based on the present invention are within the scope of the present invention.
In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.
In the description of the present invention, unless otherwise specified and limited, it is to be noted that the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, mechanically or electrically connected, or may be connected between two elements through an intermediate medium, or may be directly connected or indirectly connected, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.
Fig. 1 is a schematic diagram of an exemplary BUCK switching step-down circuit of the present invention, which includes a power supply, a driving module, a switching element, an inductor, and a load; the positive pole of power is connected with the positive pole of load, and the positive pole of power is connected with drive module's voltage input end, and drive module's output is connected with switching element's drive input end, and switching element's output is connected with inductance one end, and the inductance other end is connected with the negative pole of load, and the negative pole of power is connected with switching element's voltage input end.
In this embodiment, the power supply inputs a dc voltage to the driving module, and the driving module directly switches the element, and the switching element may be a field effect transistor or a transistor.
Fig. 2 is the utility model discloses an exemplary novel BUCK switch type step-down circuit schematic diagram, in this embodiment, drive module includes PWM chip U1 for the change of electric current in the control circuit can be according to the change of voltage, electric current in the circuit, adjusts field effect transistor's duty cycle:
the power input anode (Vin +) is respectively connected with the load output anode (Vout +) and one end of a second resistor R2, and the other end of the second resistor R2 is connected with the voltage input end (VDD port) of U1; the grounding end (GND port) of the U1 is respectively connected with one end of a first capacitor C1 and a power input cathode (Vin-), and the other end of the first capacitor C1 is connected with a power input anode (Vin +); an output end (out port) of the U1 is respectively connected with one end of a third resistor R3 and the cathode of a first diode D1, the other end of the third resistor R3 is connected with the anode of the first diode D1 in parallel and then respectively connected with a gate of the field effect transistor and one end of a ninth resistor R9, and the other end of the ninth resistor R9 is connected with the source of the field effect transistor; a current detection end (Isens port) of the U1 is connected with one end of a fifth capacitor C5, and the other end of the fifth capacitor C5 is connected with the base electrode of a first triode Q1; a control end (Verf port) of the U1 is connected with a collector of a first triode Q1, an emitter of the first triode Q1 is connected with one end of a fifth resistor R5, the other end of the fifth resistor R5 is connected with one end of an eighth resistor R8, and the other end of the eighth resistor R8 is connected with a source of a field effect transistor; the power input negative electrode (Vin-) is respectively connected with one end of a sixth resistor R6 and one end of a seventh resistor R7, and the other end of the sixth resistor R6 and the other end of the seventh resistor R7 are connected in parallel and then connected with the source electrode of the field effect transistor;
the drain electrode of the field effect transistor is respectively connected with the anode of the second diode D2 and the anode of the third diode D3, and the cathode of the second diode D2 and the cathode of the third diode D3 are connected in parallel and then connected with the anode of the load output; the drain of the field effect transistor is further connected with one end of a first inductor L1, the other end of the first inductor L1 is respectively connected with a load output cathode (Vout-) and one end of a tenth capacitor C10, and the other end of the tenth capacitor C10 is connected with a load output anode.
In this embodiment, the current of the load is realized by controlling the switching element through the U1, and the first inductor L1 functions to freewheel through the diodes D2 and D3 during the turn-off period of the switching element, thereby ensuring the stability of the output.
In this embodiment, the driving module further includes a voltage feedback circuit, which is configured to detect a current of the load and feed the current back to U1 for regulation control:
a load output anode (Vout +) is connected with one end of a second resistor R2, the other end of the second resistor R2 is respectively connected with one end of a third capacitor C3 and one end of a fourth capacitor C4, and the other end of the third capacitor C3 and the other end of the fourth capacitor C4 are connected in parallel and then connected with a voltage feedback port (FB port) of U1; the voltage feedback port of the U1 is also connected with one end of a second capacitor C2, one end of a first resistor R1 and the output end of the photoelectric coupler OC respectively, and the other end of the second capacitor C2, the other end of the first resistor R1 and the input end of the photoelectric coupler OC are connected in parallel and then connected with the current compensation port (CO port) of the U1.
In other words, in this embodiment, the U1 detects the current change of the load through the sixth resistor R6 and the seventh resistor R7, and the photocoupler OC adjusts the duty ratio of the switching element (field effect transistor) according to the voltage and current change of the output terminal, thereby achieving the purpose of stabilizing the output voltage.
In this embodiment, the driving module further includes a protection circuit, configured to detect a change in current at the output terminal, and prevent the power device from being damaged by an overcurrent:
a chip frequency setting port (OSC port) of U1 is connected to one end of a sixth capacitor C6 and one end of a seventh capacitor C7, respectively, and the other end of the seventh capacitor C7 is connected to the negative input terminal of the power supply, and is used for detecting the input current of the power supply; the other end of the sixth capacitor C6 is connected to one end of a tenth resistor R10, the other end of the tenth resistor R10 is connected to one end of an eighth capacitor C8, the other end of the eighth capacitor C8 is connected to one end of a ninth capacitor C9, the other end of the ninth capacitor C9 is connected to the collector of the second transistor Q2 and one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the base of the second transistor Q2. Can be used as slope compensation when the duty ratio is larger than 50%.
It will be understood by those skilled in the art that the foregoing embodiments are specific examples of the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in its practical application.
Claims (5)
1. A BUCK switch type voltage reduction circuit is characterized by comprising a power supply, a driving module, a switch element, an inductor and a load;
the positive pole of power with the positive pole of load is connected, the positive pole of power with drive module's voltage input end is connected, drive module's drive output with switching element's drive input end is connected, switching element's output with inductance one end is connected, the inductance other end with the negative pole of load is connected, the negative pole of power with switching element's voltage input end is connected.
2. The BUCK switching BUCK circuit of claim 1, wherein the switching element is a field effect transistor.
3. The BUCK switching BUCK circuit of claim 1, wherein the driver module includes a PWM chip U1:
the input positive pole of the power supply is respectively connected with the load output positive pole and one end of a second resistor, and the other end of the second resistor is connected with the voltage input end of U1; the grounding end of the U1 is respectively connected with one end of the first capacitor and the negative pole of the power input, and the other end of the first capacitor is connected with the positive pole of the power input;
the driving output end of the PWM chip U1 is respectively connected with one end of a third resistor and the cathode of the first diode, the other end of the third resistor is connected with the anode of the first diode in parallel and then respectively connected with the grid of the field-effect tube and one end of a ninth resistor, and the other end of the ninth resistor is connected with the source of the field-effect tube;
the current detection end of the PWM chip U1 is connected with one end of a fifth capacitor, and the other end of the fifth capacitor is connected with the base electrode of the second triode; the control end of the U1 is connected with the collector of the second triode, the emitter of the second triode is connected with one end of the fifth resistor, the other end of the fifth resistor is connected with one end of the eighth resistor, and the other end of the eighth resistor is connected with the source electrode of the field effect transistor;
the power input negative electrode is respectively connected with one end of a sixth resistor and one end of a seventh resistor, and the other end of the sixth resistor and the other end of the seventh resistor are connected in parallel and then connected with the source electrode of the field effect transistor; and the drain electrode of the field effect transistor is connected with one end of the inductor, and the other end of the inductor is connected with the negative electrode of the load.
4. The BUCK switching BUCK circuit of claim 3, wherein the driver module further includes a voltage feedback circuit:
the load output positive electrode is connected with one end of a second resistor, the other end of the second resistor is respectively connected with one end of a third capacitor and one end of a fourth capacitor, and the other end of the third capacitor and the other end of the fourth capacitor are connected in parallel and then connected with a voltage feedback port of U1;
the voltage feedback port of the U1 is also connected with one end of a second capacitor, one end of a first resistor and the emitter of a photoelectric coupler respectively, and the other end of the second capacitor, the other end of the first resistor and the collector of the photoelectric coupler are connected in parallel and then connected with the current compensation port of the U1.
5. The BUCK switching BUCK circuit of claim 3, wherein the driver module further includes a current protection circuit:
a chip frequency setting port of U1 is respectively connected with one end of a sixth capacitor and one end of a seventh capacitor, and the other end of the seventh capacitor is connected with the negative electrode of the power input;
the other end of the sixth capacitor is connected with one end of a tenth resistor, the other end of the tenth resistor is connected with one end of an eighth capacitor, the other end of the eighth capacitor is connected with one end of a ninth capacitor, the other end of the ninth capacitor is respectively connected with a collector of the second triode and one end of a fourth resistor, and the other end of the fourth resistor is connected with a base electrode of the second triode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921623855.4U CN210518108U (en) | 2019-09-26 | 2019-09-26 | BUCK switch type voltage reduction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921623855.4U CN210518108U (en) | 2019-09-26 | 2019-09-26 | BUCK switch type voltage reduction circuit |
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| Publication Number | Publication Date |
|---|---|
| CN210518108U true CN210518108U (en) | 2020-05-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921623855.4U Active CN210518108U (en) | 2019-09-26 | 2019-09-26 | BUCK switch type voltage reduction circuit |
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| Country | Link |
|---|---|
| CN (1) | CN210518108U (en) |
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2019
- 2019-09-26 CN CN201921623855.4U patent/CN210518108U/en active Active
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