CN2595067Y - Voltage limiting circuit of small-power switch power supply - Google Patents
Voltage limiting circuit of small-power switch power supply Download PDFInfo
- Publication number
- CN2595067Y CN2595067Y CN 02294119 CN02294119U CN2595067Y CN 2595067 Y CN2595067 Y CN 2595067Y CN 02294119 CN02294119 CN 02294119 CN 02294119 U CN02294119 U CN 02294119U CN 2595067 Y CN2595067 Y CN 2595067Y
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- mosfet
- diode
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Abstract
The utility model discloses a voltage limiting circuit of a small-power switch power supply. The drain pole of MOSFET is connected with the positive polarity output end of a rectification circuit, the source pole is connected with the input end of a pulse transformer of a power conversion circuit, a resistor is connected between the drain pole and the grid pole of MOSFET, the positive pole of a diode is connected with the source pole of MOSFET and the negative pole is connected with the drain pole of MOSFET, the positive pole of a diode is connected with the source pole of MOSFET and the negative pole of the diode is connected with the grid pole of MOSFET, and the negative pole of a diode is connected with the grid pole of MOSFET and the positive pole is connected with a connecting wire between the negative polarity output end of the rectification circuit and the negative polarity input end of the power conversion circuit. The utility model expands the enable input voltage range of a switch power supply, a high-integrated-level switch power supply integrated circuit which is especially designed for a low voltage level can be used for a high voltage level, and the purposes of simple switch power supply design, low cost, and high reliability can be achieved.
Description
Technical field the utility model relates to a kind of pressure limiting circuit of small-power switching power-supply.
Background technology is present, and switch power technology is very ripe, and the switching power source chip of Highgrade integration is wide in variety, cost is low, use very extensively, these circuit all are the 110V/220V/230Vac electric power system design basically, can't directly directly use on higher electric pressure.Some electronic equipment that is applied to the specific occasion needs higher input voltage range, as electronic electric energy meter, because of it need consider the situation that the electrical network single-line to ground fault causes other two phase voltages to raise, make the supply voltage of electronic equipment may reach more than the 430Vac, common Switching Power Supply can't operate as normal.This kind equipment has two kinds of supply power modes at present, and the one, adopt the analog power of traditional Industrial Frequency Transformer step-down, the 2nd, adopt a plurality of discrete formation Switching Power Supplies such as switch power controller and injectron.Preceding a kind of scheme shortcoming is that the Industrial Frequency Transformer volume is big, heaviness, and a kind of scheme shortcoming in back is the design difficulty that has increased Switching Power Supply, has increased cost, has reduced reliability.
Summary of the invention: the purpose of this utility model is a kind of pressure limiting circuit of design, make to adopt former behind this circuit can only be at the Highgrade integration of level works such as low-voltage, switching power source chip can work in the higher voltage grade cheaply.
The pressure limiting circuit of a kind of small-power switching power-supply of the utility model, by MOSFET (Metal-oxide-semicondutor type field effect transistor), resistor and diode are formed, it is installed between the interchange input rectification circuit and power conversion circuit of Switching Power Supply, the drain electrode of MOSFET connects the positive polarity output terminal of rectification circuit, source electrode connects the pulse transformer input of power conversion circuit, resistor is connected between the drain electrode and grid of MOSFET, the positive pole of diode is connected to the source electrode of MOSFET and the drain electrode that its negative pole is connected to MOSFET, the positive pole of diode is connected to the source electrode of MOSFET and the grid that its negative pole is connected to MOSFET, and the negative pole of diode is connected on the connecting line of negative polarity input of the grid of MOSFET and negative polarity output that its positive pole is connected to rectification circuit and power conversion circuit.
Wherein three diodes all are that the TVS transient voltage suppresses diode.
Between the rectification circuit of small-power switching power-supply and power conversion circuit, the utility model is installed, expanded the permission input voltage range of Switching Power Supply, the feasible Switching Power Supply integrated circuit that aims at the high integration of low-voltage grade design can be applied to voltage levels, reached the design of simplification Switching Power Supply, reduce cost, improve the purpose of reliability.
Description of drawings Fig. 1 is a circuit diagram of the present utility model.
Embodiment is as shown in Figure 1: a kind of pressure limiting circuit 19 of small-power switching power-supply, by MOSFET1 (Metal-oxide-semicondutor type field effect transistor), resistor 8 and diode are formed, be installed between the interchange input rectification circuit 20 and power conversion circuit 21 of Switching Power Supply, the drain electrode 2 of a MOSFET 1 of this circuit connects the positive polarity output terminal 18 of rectification circuit 20, source electrode 3 connects the pulse transformer input 11 of power conversion circuit 21, a resistor 8 is connected between the drain electrode 2 and grid 6 of MOSFET 1, the positive pole 10 of a diode 4 is connected to the source electrode 3 of MOSFET 1 and the drain electrode 2 that its negative pole 9 is connected to MOSFET1, the negative pole 16 that the positive pole 13 of a diode 5 is connected to the source electrode 3 of MOSFET 1 and 6, one diodes 7 of grid that its negative pole 14 is connected to MOSFET 1 is connected on the connecting line of negative polarity input 12 of the grid 6 of MOSFET 1 and negative polarity output 17 that its positive pole 15 is connected to rectification circuit 20 and power conversion circuit 21.
Wherein three diodes all are that the TVS transient voltage suppresses diode.
The expansion input voltage range is to the instantiation of 530Vac when below being power conversion circuit employing 85～265Vac intelligent switch power source chip (TOP232P).
As seen from Figure 1, MOSFET1 (model IRF830), resistor 8 (resistance 120K Ω), diode 7 (model 1.5KE400A) has constituted a basic pressure limiting circuit device, when input voltage during less than the clamped voltage (about 400Vdc) of diode 7, output voltage is grid-source voltage (3～5Vdc) that input voltage subtracts MOSFET 1, when input voltage during greater than the clamped voltage of diode 7, output voltage is grid-source voltage that the clamped voltage of diode 7 deducts MOSFET 1, so the clamped voltage of diode 7 has determined the maximum output voltage of MOSFET 1.Resistor 8 is used to diode 7 and MOSFET 1 that biasing is provided.The input voltage that surpasses diode 7 clamped voltage segments will mainly fall on MOSFET 1.The gate protection of MOSFET1 is provided under diode 5 (model SA12) normal condition.Diode 4 (model 1.5KE400A) provides drain electrode-source electrode protection of MOSFET 1; when the voltage between the drain electrode-source electrode that is added in MOSFET 1 surpasses the voltage of turning back (about 400Vdc) of diode 4; diode 4 conductings; the rising of deboost, drain electrode-source electrode of protection MOSFET1 is not breakdown.Diode 4, diode 5, diode 7 has also constituted the surge voltage limit circuit simultaneously, when input voltage surpasses diode 4, diode 5, during the clamped voltage of diode 7, diode 4, diode 5, diode 7 conductings, the input surge voltage is limited in certain scope, maximum output voltage is limited in diode 5, in the scope of the maximum clamped voltage sum of diode 7, thereby guarantee under normal over-voltage condition or greater than the surge voltage (12/50uS of 530Vac, 10/700uS) under the situation, output voltage is no more than the input voltage range (450Vdc) of intelligent switch power source operate as normal.
Claims (4)
1, a kind of pressure limiting circuit of small-power switching power-supply, by MOSFET (1) (Metal-oxide-semicondutor type field effect transistor), resistor (8) and diode are formed, it is installed between the interchange input rectification circuit (20) and power conversion circuit (21) of Switching Power Supply, it is characterized in that: the drain electrode (2) of MOSFET (1) connects the positive polarity output terminal (18) of rectification circuit (20), source electrode (3) connects the pulse transformer input (11) of power conversion circuit (21), resistor (8) is connected between the drain electrode (2) and grid (6) of MOSFET (1), the positive pole (10) of diode (4) is connected to the source electrode (3) of MOSFET (1) and the drain electrode (2) that its negative pole (9) is connected to MOSFET (1), the positive pole (13) of diode (5) is connected to the source electrode (3) of MOSFET (1) and the grid (6) that its negative pole (14) is connected to MOSFET (1), and the negative pole (16) of diode (7) is connected on the connecting line of negative polarity input (12) of the grid (6) of MOSFET (1) and negative polarity output (17) that its positive pole (15) is connected to rectification circuit (20) and power conversion circuit (21).
2, the pressure limiting circuit of small-power switching power-supply as claimed in claim 1 is characterized in that: the drain electrode (2) and the diode (4) between the source electrode (3) that are connected to MOSFET (1) are that the TVS transient voltage suppresses diode.
3, the pressure limiting circuit of small-power switching power-supply as claimed in claim 1 is characterized in that: the grid (6) and the diode (5) between the source electrode (3) that are connected to MOSFET (1) are that the TVS transient voltage suppresses diode.
4, the pressure limiting circuit of small-power switching power-supply as claimed in claim 1 is characterized in that: the diode (7) that is connected between the negative polarity input (12) of the negative polarity output (17) of the grid (6) of MOSFET (1) and rectification circuit (20) and power conversion circuit (21) is that the TVS transient voltage suppresses diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02294119 CN2595067Y (en) | 2002-12-27 | 2002-12-27 | Voltage limiting circuit of small-power switch power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02294119 CN2595067Y (en) | 2002-12-27 | 2002-12-27 | Voltage limiting circuit of small-power switch power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2595067Y true CN2595067Y (en) | 2003-12-24 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 02294119 Expired - Fee Related CN2595067Y (en) | 2002-12-27 | 2002-12-27 | Voltage limiting circuit of small-power switch power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2595067Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109541424A (en) * | 2018-10-10 | 2019-03-29 | 深圳市崧盛电子股份有限公司 | A kind of test PDFN encapsulation metal-oxide-semiconductor electric stress device and Switching Power Supply |
-
2002
- 2002-12-27 CN CN 02294119 patent/CN2595067Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109541424A (en) * | 2018-10-10 | 2019-03-29 | 深圳市崧盛电子股份有限公司 | A kind of test PDFN encapsulation metal-oxide-semiconductor electric stress device and Switching Power Supply |
| CN109541424B (en) * | 2018-10-10 | 2020-02-21 | 广东省崧盛电源技术有限公司 | Device for testing electric stress of PDFN (polymer dispersed non-leaded semiconductor) packaged MOS (metal oxide semiconductor) tube and switching power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20031224 Termination date: 20100127 |