CN203056540U - Auxiliary output protective circuit for Set Top Box circuit board - Google Patents
Auxiliary output protective circuit for Set Top Box circuit board Download PDFInfo
- Publication number
- CN203056540U CN203056540U CN 201320046094 CN201320046094U CN203056540U CN 203056540 U CN203056540 U CN 203056540U CN 201320046094 CN201320046094 CN 201320046094 CN 201320046094 U CN201320046094 U CN 201320046094U CN 203056540 U CN203056540 U CN 203056540U
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- resistance
- triode
- resistor
- top box
- circuit board
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Abstract
The utility model discloses an auxiliary output protective circuit for a Set Top Box circuit board. The auxiliary output protective circuit comprises components of a first resistor and the like. A fourth resistor and the seventh resistor are connected in series. Collector electrodes of the fourth resistor, the seventh resistor and a fourth triode are connected with a base electrode of a third triode. A Zener diode is connected with an emitting electrode of the third triode. A fifth resistor is connected with a collector electrode of the third triode. A second resistor and the fifth resistor are connected in series. The second resistor and the fifth resistor are connected with a base electrode of a first triode. A collector electrode of the first triode is connected with an emitting electrode of a second triode. A sixth resistor is connected with a collector electrode of the second triode. The sixth resistor and a ninth resistor are connected in series. An eighth resistor is connected with a base electrode of a fourth triode. A third resistor is connected with a base electrode of the second triode. The first resistor is connected with the collector electrode of the first triode and the emitting electrode of the second triode. A capacitor is connected with the first resistor. The auxiliary output protective circuit for the Set Top Box circuit board has functions of over-current protection, over-voltage protection and short circuit protection, and can protect auxiliary output.
Description
Technical field
The utility model relates to a kind of set-top box circuit board, particularly relates to a kind of bypass output protection circuit of set-top box circuit board.
Background technology
Many group output Switching Power Supplies have the more perfect defencive function except main road output, and bypass is exported most unprotect or protection imperfection, very easily damage when unusual condition such as long-time short circuit, overcurrent occurring, also easily cause supporting with it system failure.
The utility model content
Technical problem to be solved in the utility model provides a kind of bypass output protection circuit of set-top box circuit board, and it has overcurrent, overvoltage, short-circuit protection function, the output of protection bypass.
The utility model solves above-mentioned technical problem by following technical proposals: a kind of bypass output protection circuit of set-top box circuit board; it is characterized in that; it comprises first resistance; second resistance; the 3rd resistance; the 4th resistance; the 5th resistance; the 6th resistance; the 7th resistance; the 8th resistance; the 9th resistance; first triode; second triode; the 3rd triode; the 4th triode; electric capacity; voltage stabilizing didoe; the 4th resistance is connected with the 7th resistance; the 4th resistance; the 7th resistance; the collector electrode of the 4th triode all is connected with the base stage of the 3rd triode; voltage stabilizing didoe is connected with the emitter of the 3rd triode; the 5th resistance is connected with the collector electrode of the 3rd triode; second resistance is connected with the 5th resistance; second resistance; the 5th resistance all is connected with the base stage of first triode; the collector electrode of first triode is connected with the emitter of second triode; the 6th resistance is connected with the collector electrode of second triode; the 6th resistance is connected with the 9th resistance; the 8th resistance is connected with the base stage of the 4th triode; the 3rd resistance is connected with the base stage of second triode; the collector electrode of first resistance and first triode; the emitter of second triode connects, and electric capacity is connected with first resistance.
Preferably, the emitter of described electric capacity, the 3rd resistance, the 7th resistance, the 9th resistance, voltage stabilizing didoe, the 4th triode ground connection all.
Preferably, the emitter of described second resistance, the 4th resistance, first triode all connects a voltage input end, and the 8th resistance connects a switch control end, and electric capacity, first resistance all connect an output.
Positive progressive effect of the present utility model is: the utility model is stable sensitive reliable; have overcurrent (OCP), overvoltage (OVP), short-circuit protection function, also can effectively improve the too high bad problem of intersection regulation that causes that bypass voltage raises of main road output loading.
Description of drawings
Fig. 1 is the circuit diagram of the bypass output protection circuit of a kind of set-top box circuit board of the utility model.
Embodiment
Provide the utility model preferred embodiment below in conjunction with accompanying drawing, to describe the technical solution of the utility model in detail.
As shown in Figure 1; the bypass output protection circuit of a kind of set-top box circuit board of the utility model; comprise first resistance R 1; second resistance R 2; the 3rd resistance R 3; the 4th resistance R 4; the 5th resistance R 5; the 6th resistance R 6; the 7th resistance R 7; the 8th resistance R 8; the 9th resistance R 9; the first triode Q1; the second triode Q2; the 3rd triode Q3; the 4th triode Q4; capacitor C 1; voltage stabilizing didoe ZD1; the 4th resistance R 4 is connected with the 7th resistance R 7; the 4th resistance R 4; the 7th resistance R 7; the collector electrode of the 4th triode Q4 all is connected with the base stage of the 3rd triode Q3; voltage stabilizing didoe ZD1 is connected with the emitter of the 3rd triode Q3; the 5th resistance R 5 is connected with the collector electrode of the 3rd triode Q3; second resistance R 2 is connected with the 5th resistance R 5; second resistance R 2; the 5th resistance R 5 all is connected with the base stage of the first triode Q1; the collector electrode of the first triode Q1 is connected with the emitter of the second triode Q2; the 6th resistance R 6 is connected with the collector electrode of the second triode Q2; the 6th resistance R 6 is connected with the 9th resistance R 9; the 8th resistance R 8 is connected with the base stage of the 4th triode Q4; the 3rd resistance R 3 is connected with the base stage of the second triode Q2; the collector electrode of first resistance R 1 and the first triode Q1; the emitter of the second triode Q2 connects, and capacitor C 1 is connected with first resistance R 1.The emitter of capacitor C 1, the 3rd resistance R 3, the 7th resistance R 7, the 9th resistance R 9, voltage stabilizing didoe ZD1, the 4th triode Q4 is ground connection all.The emitter of second resistance R 2, the 4th resistance R 4, the first triode Q1 all connects a voltage input end VIN, and the 8th resistance R 8 connects a switch control end PSON, and capacitor C 1, first resistance R 1 all connect an output VOUT.
The operation principle of the bypass output protection circuit of a kind of set-top box circuit board of the utility model is as follows: after the voltage input end VIN energising; when switch control end PSON is low level; the 4th triode Q4 ends; the base stage high level of the 3rd triode Q3, the 3rd triode Q3 conducting, the first triode Q1 base stage low level; the first triode Q1 conducting; voltage input end VIN,, exports through output VOUT after capacitor C 1 filtering through first resistance R 1 through the first triode Q1 again.Otherwise when switch control end PSON was high level, the first triode Q1 cut-off circuit was off state.
Organize the unbalanced voltage superelevation that causes of load when the VIN electric voltage exception or because of each, voltage stabilizing didoe ZD1 provide clamp voltage, makes output voltage in normal range (NR), realizes that output over-voltage protection and elimination are by the unbalanced voltage superelevation that causes of each group load.
When output short-circuit, 1 pressure drop of first resistance R increases, the second triode Q2 conducting, and the 4th triode Q4 conducting, the 3rd triode Q3 ends, and the first triode Q1 ends, and circuit turn-offs, and realizes short-circuit protection.Overcurrent protection is similar to short-circuit protection; when overcurrent takes place; 1 pressure drop of first resistance R increases; the second triode Q2 tends to saturation conduction, and the 4th triode Q4 tends to saturation conduction, and the 3rd triode Q3 trend is ended; first triode Q1 trend is ended; output voltage descends, and further cut-off current is realized overcurrent protection.
Those skilled in the art can carry out various remodeling and change to the utility model.Therefore, the utility model has covered various remodeling and the change in the scope that falls into appending claims and equivalent thereof.
Claims (3)
1. the bypass output protection circuit of a set-top box circuit board; it is characterized in that; it comprises first resistance; second resistance; the 3rd resistance; the 4th resistance; the 5th resistance; the 6th resistance; the 7th resistance; the 8th resistance; the 9th resistance; first triode; second triode; the 3rd triode; the 4th triode; electric capacity; voltage stabilizing didoe; the 4th resistance is connected with the 7th resistance; the 4th resistance; the 7th resistance; the collector electrode of the 4th triode all is connected with the base stage of the 3rd triode; voltage stabilizing didoe is connected with the emitter of the 3rd triode; the 5th resistance is connected with the collector electrode of the 3rd triode; second resistance is connected with the 5th resistance; second resistance; the 5th resistance all is connected with the base stage of first triode; the collector electrode of first triode is connected with the emitter of second triode; the 6th resistance is connected with the collector electrode of second triode; the 6th resistance is connected with the 9th resistance; the 8th resistance is connected with the base stage of the 4th triode; the 3rd resistance is connected with the base stage of second triode; the collector electrode of first resistance and first triode; the emitter of second triode connects, and electric capacity is connected with first resistance.
2. the bypass output protection circuit of a kind of set-top box circuit board as claimed in claim 1 is characterized in that, the emitter of described electric capacity, the 3rd resistance, the 7th resistance, the 9th resistance, voltage stabilizing didoe, the 4th triode is ground connection all.
3. the bypass output protection circuit of a kind of set-top box circuit board as claimed in claim 1; it is characterized in that; the emitter of described second resistance, the 4th resistance, first triode all connects a voltage input end; the 8th resistance connects a switch control end, and electric capacity, first resistance all connect an output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320046094 CN203056540U (en) | 2013-01-28 | 2013-01-28 | Auxiliary output protective circuit for Set Top Box circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320046094 CN203056540U (en) | 2013-01-28 | 2013-01-28 | Auxiliary output protective circuit for Set Top Box circuit board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203056540U true CN203056540U (en) | 2013-07-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320046094 Expired - Fee Related CN203056540U (en) | 2013-01-28 | 2013-01-28 | Auxiliary output protective circuit for Set Top Box circuit board |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203056540U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105720551A (en) * | 2016-04-25 | 2016-06-29 | 武汉海微科技有限公司 | Output overcurrent protection circuit of power supply |
-
2013
- 2013-01-28 CN CN 201320046094 patent/CN203056540U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105720551A (en) * | 2016-04-25 | 2016-06-29 | 武汉海微科技有限公司 | Output overcurrent protection circuit of power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20130710 Termination date: 20150128 |
|
| EXPY | Termination of patent right or utility model |