CN203761284U - Low-power step-down circuit - Google Patents
Low-power step-down circuit Download PDFInfo
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- CN203761284U CN203761284U CN201320882198.1U CN201320882198U CN203761284U CN 203761284 U CN203761284 U CN 203761284U CN 201320882198 U CN201320882198 U CN 201320882198U CN 203761284 U CN203761284 U CN 203761284U
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- resistance
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- voltage
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Abstract
The utility model discloses a low-power step-down circuit, and the circuit comprises a rectifier bridge, a first resistor, a second resistor, a third resistor, a sixth resistor, a first MOS tube, a second MOS tube, and a filter capacitor. The input end of the rectifier bridge is connected with an alternating-current power supply, and the positive direct-current output end of the rectifier bridge is connected with the first end of the first resistor, the first end of the third resistor, and the first end of the sixth resistor. The second end of the first resistor is connected with the first end of the second resistor, and the grid electrode of the first MOS tube. The second end of the third resistor is connected with the drain electrode of the first MOS tube and the grid electrode of the second MOS tube. The drain electrode of the second MOS tube is connected with the second end of the sixth resistor. The source electrode of the second MOS tube is connected with the first end of the filter capacitor and a first voltage output end. The negative direct-current output end of the rectifier bridge, the second end of the second resistor, the source electrode of the first MOS tube, the second end of the filter capacitor and a second voltage output end are all grounded. The circuit provided by the utility model is simple in structure and small in size.
Description
Technical field
The utility model relates to a kind of reduction voltage circuit, especially a kind of small-power reduction voltage circuit.
Background technology
At present, the various device using all adopts mains-supplied substantially, current mains-supplied is ac high-voltage, is low-voltage DC and most of circuit needs, therefore most equipment all need that ac high voltage source is carried out to step-down, rectification and filtering processes could be for late-class circuit.Traditional reduction voltage circuit is generally capacitance-resistance voltage reduction circuit, and components and parts are many, circuit structure complexity, and volume is large, is not easy to integrated.
Utility model content
Technical problem to be solved in the utility model be to provide a kind of simple in structure, be convenient to integrated small-power reduction voltage circuit.
The utility model solves its technical problem and adopts small-power reduction voltage circuit, comprises rectifier bridge, the first resistance, the second resistance, the 3rd resistance, the 6th resistance, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor and filter capacitor, connect AC power between the first input end of described rectifier bridge and the second input, the anodal DC output end of described rectifier bridge and the first end of described the first resistance, the first end of described the 3rd resistance, the first end of described the 6th resistance connects, the second end of described the first resistance and the first end of described the second resistance, the grid of described the first metal-oxide-semiconductor connects, the second end of described the 3rd resistance and the drain electrode of described the first metal-oxide-semiconductor, the grid of described the second metal-oxide-semiconductor connects, and the drain electrode of described the second metal-oxide-semiconductor is connected with the second end of described the 6th resistance, and the source electrode of described the second metal-oxide-semiconductor is connected with the first end of described filter capacitor, the first voltage output end connects, the negative pole DC output end of described rectifier bridge, the second end of described the second resistance, the source electrode of described the first metal-oxide-semiconductor, the second end of described filter capacitor and the equal ground connection of second voltage output.
Further, described small-power reduction voltage circuit also comprises the first voltage-stabiliser tube and the second voltage-stabiliser tube, the negative electrode of described the first voltage-stabiliser tube is connected with the grid of described the first metal-oxide-semiconductor, the anode of described the first voltage-stabiliser tube is connected with the source electrode of described the first metal-oxide-semiconductor, the negative electrode of described the second voltage-stabiliser tube is connected with the grid of described the second metal-oxide-semiconductor, and the anode of described the second voltage-stabiliser tube is connected with the second end of described filter capacitor.
Further, described small-power reduction voltage circuit also comprises the 4th resistance, described the 4th resistance is connected between the drain electrode of described the first metal-oxide-semiconductor and the grid of described the second metal-oxide-semiconductor, and described the 4th resistance is connected between the second end of described the 3rd resistance and the grid of described the second metal-oxide-semiconductor.
Further, be parallel with the 5th resistance at the two ends of described the second resistance.
Further, between the first input end of described rectifier bridge and the second input, be parallel with piezo-resistance.
Further, between the first input end of described rectifier bridge and AC power, be in series with fuse-link.
The beneficial effects of the utility model are: due to small-power reduction voltage circuit of the present utility model, do not use transformer, the devices such as inductance just can complete buck functionality, nor use capacitance-resistance voltage reduction circuit mode, circuit structure is simple, be convenient to integratedly, and can in whole sine wave period, work.
Brief description of the drawings
Fig. 1 is circuit theory diagrams of the present utility model.
Shown in figure: 11-AC power, 12-fuse-link, 13-piezo-resistance, 14-rectifier bridge, 21-the first resistance, 22-the second resistance, 23-the 3rd resistance, 24-the 4th resistance, 25-the 5th resistance, 26-the 6th resistance, 31-the first metal-oxide-semiconductor, 32-the second metal-oxide-semiconductor, 41-the first voltage-stabiliser tube, 42-the second voltage-stabiliser tube, 51-filter capacitor, 61-the first voltage output end, 62-second voltage output.
Embodiment
Below in conjunction with drawings and Examples, the utility model is further illustrated.
As shown in Figure 1, small-power reduction voltage circuit of the present utility model, comprises rectifier bridge 14, the first resistance 21, the second resistance 22, the 3rd resistance 23, the 6th resistance 26, the first metal-oxide-semiconductor 31, the second metal-oxide-semiconductor 32 and filter capacitor 51, connect AC power between the first input end of described rectifier bridge 14 and the second input, the anodal DC output end of described rectifier bridge 14 and the first end of described the first resistance 21, the first end of described the 3rd resistance 23, the first end of described the 6th resistance 26 connects, the second end of described the first resistance 21 and the first end of described the second resistance 22, the grid of described the first metal-oxide-semiconductor 31 connects, the second end of described the 3rd resistance 23 and the drain electrode of described the first metal-oxide-semiconductor 31, the grid of described the second metal-oxide-semiconductor 32 connects, and the drain electrode of described the second metal-oxide-semiconductor 32 is connected with the second end of described the 6th resistance 26, and the source electrode of described the second metal-oxide-semiconductor 32 is connected with the first end of described filter capacitor 51, the first voltage output end 61 connects, the negative pole DC output end of described rectifier bridge 14, the second end of described the second resistance 22, the source electrode of described the first metal-oxide-semiconductor 31, the second end of described filter capacitor 51 and the equal ground connection of second voltage output 62.
Described metal-oxide-semiconductor refers to insulating gate type field effect tube, and metal-oxide-semiconductor is divided into four classes, N channel enhancement, N channel depletion type, P-channel enhancement type, P channel depletion type, and the utility model adopts N channel enhancement.The AC high voltage that AC power 11 provides is after rectifier bridge 14 rectifications, negative half period in input sine wave is inverted positive half cycle, form pulse direct current, this voltage provides after baseband signal and power supply output ripple direct current for late-class circuit, the first resistance 21 and the second resistance 22 form the upper and lower biasing circuit of the first metal-oxide-semiconductor 31, the gate source voltage of the first metal-oxide-semiconductor 31 equals the voltage at the second resistance 22 two ends, when the voltage at the second resistance 22 two ends is less than the first metal-oxide-semiconductor 31 cut-in voltage U
gS (th)time, the first metal-oxide-semiconductor 31 is by the drain electrode output high level of, the first metal-oxide-semiconductor 31, the second metal-oxide-semiconductor 32 conductings, and input voltage charges to filter capacitor 51 and provides output voltage for late-class circuit; When the voltage at the second resistance 22 two ends is more than or equal to the first metal-oxide-semiconductor 31 cut-in voltage U
gS (th)time, the first metal-oxide-semiconductor 31 conductings, the drain electrode output low level of the first metal-oxide-semiconductor 31, the second metal-oxide-semiconductor 32 by, input voltage stops filter capacitor 51 to charge, and discharges for late-class circuit provides output voltage, thereby realize the object of step-down by filter capacitor 51; Owing to only having the voltage when the second resistance 22 two ends to be less than the first metal-oxide-semiconductor 31 cut-in voltage U
gS (th)time, just filter capacitor 51 is charged, therefore can carry out controlled hypotension ratio by the resistance ratio of controlling the first resistance 21 and the second resistance 22; The 3rd resistance 23 is the upper offset resistance of the first metal-oxide-semiconductor 31; play current-limiting protection; in the time of the first metal-oxide-semiconductor 31 conducting, prevent from forming large electric current and damaging the first metal-oxide-semiconductor 31 between the leakage, source of the first metal-oxide-semiconductor 31, described the 6th resistance 26 is the upper offset resistance of the second metal-oxide-semiconductor 32.
In order to protect the first metal-oxide-semiconductor 31 and the second metal-oxide-semiconductor 32; make both gate source voltages separately in prescribed limit; described small-power reduction voltage circuit also comprises the first voltage-stabiliser tube 41 and the second voltage-stabiliser tube 42; the negative electrode of described the first voltage-stabiliser tube 41 is connected with the grid of described the first metal-oxide-semiconductor 31; the anode of described the first voltage-stabiliser tube 41 is connected with the source electrode of described the first metal-oxide-semiconductor 31; the negative electrode of described the second voltage-stabiliser tube 42 is connected with the grid of described the second metal-oxide-semiconductor 32, and the anode of described the second voltage-stabiliser tube 42 is connected with the second end of described filter capacitor 51.
Keep apart in order to make the first metal-oxide-semiconductor 31 and the second metal-oxide-semiconductor 32, during simultaneously for fear of the second metal-oxide-semiconductor 32 conducting, the electric current that flows through the second metal-oxide-semiconductor 32 grids is excessive, as preferred embodiment, described small-power reduction voltage circuit also comprises the 4th resistance 24, described the 4th resistance 24 is connected between the drain electrode of described the first metal-oxide-semiconductor 31 and the grid of described the second metal-oxide-semiconductor 32, and described the 4th resistance 24 is connected between the second end of described the 3rd resistance 23 and the grid of described the second metal-oxide-semiconductor 32, and described the 4th resistance 24 plays isolation and current limliting.
Owing to being that resistance ratio by controlling the first resistance 21 and the second resistance 22 is carried out controlled hypotension ratio, in the situation that input voltage is certain, in order to obtain the output voltage of various different electric pressures, because the resistance that can buy on market is all standard resistor, in the time of some output voltage of needs, there is no standard resistor corresponding thereto, just can obtain non-standard resistance by the mode of two standard resistor parallel connections, therefore, as preferred embodiment, be parallel with the 5th resistance 25 at the two ends of described the second resistance 22.
Excessive and damage rectifier bridge 14 in order to prevent from being added in the voltage at rectifier bridge 14 two ends, between the first input end of described rectifier bridge 14 and the second input, be parallel with piezo-resistance 13, described piezo-resistance 13 works to input overvoltage protection.
Excessive and damage rectifier bridge 14 in order to prevent from flowing through rectifier bridge 14 electric currents, between the first input end of described rectifier bridge 14 and AC power, be in series with fuse-link 12, described fuse-link 12 plays input overcurrent protection.
Claims (6)
1. a small-power reduction voltage circuit, is characterized in that: comprise rectifier bridge (14), the first resistance (21), the second resistance (22), the 3rd resistance (23), the 6th resistance (26), the first metal-oxide-semiconductor (31), the second metal-oxide-semiconductor (32) and filter capacitor (51), connect AC power between the first input end of described rectifier bridge (14) and the second input, the first end of the anodal DC output end of described rectifier bridge (14) and described the first resistance (21), the first end of described the 3rd resistance (23), the first end of described the 6th resistance (26) connects, the first end of the second end of described the first resistance (21) and described the second resistance (22), the grid of described the first metal-oxide-semiconductor (31) connects, the drain electrode of the second end of described the 3rd resistance (23) and described the first metal-oxide-semiconductor (31), the grid of described the second metal-oxide-semiconductor (32) connects, and the drain electrode of described the second metal-oxide-semiconductor (32) is connected with the second end of described the 6th resistance (26), and the source electrode of described the second metal-oxide-semiconductor (32) is connected with the first end of described filter capacitor (51), the first voltage output end (61) connects, the negative pole DC output end of described rectifier bridge (14), the second end of described the second resistance (22), the source electrode of described the first metal-oxide-semiconductor (31), the second end of described filter capacitor (51) and second voltage output (62) be ground connection all.
2. small-power reduction voltage circuit as claimed in claim 1, it is characterized in that: described small-power reduction voltage circuit also comprises the first voltage-stabiliser tube (41) and the second voltage-stabiliser tube (42), the negative electrode of described the first voltage-stabiliser tube (41) is connected with the grid of described the first metal-oxide-semiconductor (31), the anode of described the first voltage-stabiliser tube (41) is connected with the source electrode of described the first metal-oxide-semiconductor (31), the negative electrode of described the second voltage-stabiliser tube (42) is connected with the grid of described the second metal-oxide-semiconductor (32), and the anode of described the second voltage-stabiliser tube (42) is connected with the second end of described filter capacitor (51).
3. small-power reduction voltage circuit as claimed in claim 1 or 2, it is characterized in that: described small-power reduction voltage circuit also comprises the 4th resistance (24), described the 4th resistance (24) is connected between the drain electrode of described the first metal-oxide-semiconductor (31) and the grid of described the second metal-oxide-semiconductor (32), and described the 4th resistance (24) is connected between the second end of described the 3rd resistance (23) and the grid of described the second metal-oxide-semiconductor (32).
4. small-power reduction voltage circuit as claimed in claim 1 or 2, is characterized in that: be parallel with the 5th resistance (25) at the two ends of described the second resistance (22).
5. small-power reduction voltage circuit as claimed in claim 1 or 2, is characterized in that: between the first input end of described rectifier bridge (14) and the second input, be parallel with piezo-resistance (13).
6. small-power reduction voltage circuit as claimed in claim 1 or 2, is characterized in that: between the first input end of described rectifier bridge (14) and AC power, be in series with fuse-link (12).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320882198.1U CN203761284U (en) | 2013-12-30 | 2013-12-30 | Low-power step-down circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320882198.1U CN203761284U (en) | 2013-12-30 | 2013-12-30 | Low-power step-down circuit |
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| Publication Number | Publication Date |
|---|---|
| CN203761284U true CN203761284U (en) | 2014-08-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320882198.1U Expired - Fee Related CN203761284U (en) | 2013-12-30 | 2013-12-30 | Low-power step-down circuit |
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| Country | Link |
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| CN (1) | CN203761284U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111181389A (en) * | 2020-02-19 | 2020-05-19 | 东风电子科技股份有限公司 | Power supply voltage reduction circuit and corresponding control system |
-
2013
- 2013-12-30 CN CN201320882198.1U patent/CN203761284U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111181389A (en) * | 2020-02-19 | 2020-05-19 | 东风电子科技股份有限公司 | Power supply voltage reduction circuit and corresponding control system |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140806 Termination date: 20171230 |
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| CF01 | Termination of patent right due to non-payment of annual fee |