CN202121562U - Power switch circuit and digital television receiving terminal - Google Patents
Power switch circuit and digital television receiving terminal Download PDFInfo
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- CN202121562U CN202121562U CN2011200798210U CN201120079821U CN202121562U CN 202121562 U CN202121562 U CN 202121562U CN 2011200798210 U CN2011200798210 U CN 2011200798210U CN 201120079821 U CN201120079821 U CN 201120079821U CN 202121562 U CN202121562 U CN 202121562U
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Abstract
The utility model provides a power switch circuit comprising a power down negative pulse generating circuit, a negative pulse voltage clamping and forward bias circuit, a first level switch circuit, a voltage delay circuit, a voltage selection circuit, and a maximum voltage source with normally open system and normally open modules. A signal input terminal of the power down negative pulse generating circuit connects a second level switch circuit through an earliest power down track voltage source for a standby module; a signal output terminal connects the first level switch circuit through the negative pulse voltage clamping and forward bias circuit; a signal input terminal of the first level switch circuit connects the second level switch circuit; the maximum voltage source with normally open system and normally open modules connects the voltage selection circuit through the voltage delay circuit; the voltage selection circuit also connects the earliest power down track voltage source for a standby module; the other end of the voltage selection circuit connects an input signal input terminal of the first level switch circuit and an signal input terminal of the second level switch circuit; and the second level switch circuit connects the standby module. The power switch circuit and digital television receiving terminal provided by the utility model can reduce system consumption.
Description
Technical field
The utility model belongs to the power management techniques field, relates in particular to a kind of power supply power switch circuit.
Background technology
Now, include a large amount of high-speed figure chips in the electronic circuit, these chips are very responsive to the mutation current responding ability of power rail.In order to improve the current transient response of power distribution network; The designer need increase dissimilar usually on power distribution network; Appearance is worth different electric capacity as by-pass capacitor, and modular design is big capacity alminium electrolytic condenser or several different other ceramic condensers of appearance value level of tantalum electric capacity parallel connection.But since power distribution network on the parallel connection jumbo electric capacity, cause power distribution network electric voltage dropping after power down longer to the needed time of 0V.If before power distribution network voltage drops into 0V as yet, do not power on, then the electrifying timing sequence of power distribution network and power-on time can change, thereby have influenced system's electrifying timing sequence and resetting time, might cause system to start.Therefore, system's power down needs the interval of a period of time to power on next time, and the shunt capacitance that this spacer segment time approximates on the power distribution network is discharged the needed time fully.If too big during this period of time, then can cause customer complaint, problem such as waits for too long when the test link is switched in the process of producing product.
In order to reduce power consumption, most of electronic product has all possessed standby mode.And in the electronic system idle function; Some design is that for example metal-oxide-semiconductor (also is called MOSFET, Metal Oxide Semiconductor Field Effect Transistor through the increase switching device; The MOS type FET); Perhaps BJT (Bipolar Junction Transistor, bipolar transistor) etc. realizes the supply line of standby module through the distribution network of cutting off the electricity supply.This just means that switching device turn-offs when certain voltage is arrived in system's power down, and the big electric capacity that exists in the loop that is turned off just might can't carry out repid discharge, thereby has residual voltage.In addition, often have a plurality of power transfer module in the system, generally all there is the threshold values operating voltage in these modules.When voltage on the power distribution network is lower than the threshold voltage of its work; Transducer quits work; The Da Rong value electric capacity of parallel connection can't carry out repid discharge in the power distribution network of its power input, thereby has residual voltage, has influenced system's high-speed switch machine performance.
Under the system standby pattern, exist non-standby module (also being called operational module) and standby module, the former is still in running order when standby, and the latter has been in low power consumpting state when standby, and perhaps its power supply is turned off.In design, often there is signal transmission path between non-standby module and the standby module.When system standby; The power supply meeting of non-standby module is poured in down a chimney in the standby module that is cut off power supply through signal transmission path; Cause having a undesired direct voltage (pouring in down a chimney voltage) on the power distribution network of standby module, influenced normally waking up of standby module.
Therefore, reduce system's power down and become a challenge in the complicated electronic system design day by day with the reliability that improves the system standby arousal function at interval to power-on time.The key of head it off just is how to accomplish not influence the shunt capacitance value size of system power supply distribution network; Do not change existing power supply conversion plan and standby implementation; The power consumption that is not increased under the normal operation is under the precondition, reduces the parallel resistance on the power rail.
And use resistance as the parallel connection of the shunt capacitance in dummy load and the power distribution network, become the previous the most frequently used method of order with this dummy load as a low resistance discharge path.Except that this function, can make power rail on the standby module that is cut off power supply pour in down a chimney voltage and reach acceptable degree through this resistance of adjustment.
The defective of prior art is: when resistance value was big, the capacitance discharges electric current was too small, and the power rail power down time improves not obvious; Resistance value hour, the power loss introduced of dummy load is more considerable thus under system's normal operation.For example, have the power supply supply network of a 12V in the system, total capacitance of parallel connection is 1000uF on it.Reduce to 0V if hope its voltage in 500mS of shutdown back from 12V, then need the about 330R resistance of parallelly connected dummy load even littler.Under this application conditions, system is when operate as normal, and the extra power consumption of dummy load introducing has increased 0.43W at least thus.
In standby scheme with the mode of cutting off the electricity supply; Use resistance to reduce the voltage that pours in down a chimney on the power rail of standby module as dummy load; Often require this resistance be tens of ohm level other, the extra power consumption that other resistance of this resistance level is introduced can be quite big, this also is unacceptable.
The utility model content
The purpose of the utility model is to provide a kind of power switch circuit, is intended to solve the excess power loss problem that use resistance of the prior art is introduced as dummy load.
The utility model is achieved in that a kind of power switch circuit, is used to accelerate the power down of each road power rail after system's power down; And each road is turned off the voltage that pours in down a chimney of power rail when reducing standby; It connects the standby module, and said power switch circuit comprises that the power down negative pulse produces circuit, negative pulse voltage clamp and forward bias circuit; First order switching circuit; The voltage delay circuit, voltage selecting circuit, second level switching circuit; The standby module is power down railway voltage source at first; System Chang Kaimo piece is often opened sources, and wherein: said power down negative pulse produces circuit and electrically connects said second level switching circuit in power down railway voltage source at first through the standby module, and the other end that said power down negative pulse produces circuit electrically connects said first order switching circuit first signal input part through negative pulse voltage clamp and forward bias circuit; Said first order switching circuit signal output part electrically connects said second level switching circuit; Said system Chang Kaimo piece is often opened sources electrically connects said voltage selecting circuit through the voltage delay circuit first signal input part; The secondary signal input of said voltage selecting circuit electrically connects standby module power down railway voltage source at first, and the signal output part of voltage selecting circuit electrically connects the secondary signal input of said first order switching circuit; Said second level switching circuit electrically connects said standby module.
More excellent, said power down negative pulse produces circuit and comprises first diode, first resistance; Second electric capacity and the 3rd resistance; Wherein, the positive pole of said first diode electrically connects standby module power down railway voltage source at first, and negative pole is through first grounding through resistance; One end of second electric capacity connects the negative pole of first diode, and the other end is through the 3rd grounding through resistance.
More excellent, said negative pulse voltage clamp and forward bias circuit comprise second resistance, the 4th resistance and second diode, and wherein, an end of said second resistance connects standby module power down railway voltage source at first, and the other end is through the 3rd grounding through resistance; One end of the 4th resistance connects second resistance and the 3rd resistance, and the other end connects second diode cathode, the plus earth of said second diode.
More excellent, said first order switching circuit comprises a NPN type triode, the 5th resistance, and the base stage of a said NPN type triode electrically connects the negative pole and second resistance of second diode, and collector electrode electrically connects the 5th resistance, grounded emitter.
More excellent; Said voltage delay circuit comprises the 9th resistance; The 4th diode and the 3rd electric capacity, wherein, an end of said the 9th resistance electrically connects the Chang Kaimo of system piece and often opens sources; The other end electrically connects the positive pole of the 4th diode, and the negative pole of the 4th diode is through the 3rd capacity earth.
More excellent, said voltage selecting circuit comprises the 3rd diode, and the positive pole of said the 3rd diode connects standby module power down railway voltage source at first, and negative pole connects the negative pole and the 5th resistance of the 4th diode.
More excellent, said second level switching circuit comprises the 6th resistance, the 8th resistance, transistor seconds; The 7th resistance, the tenth resistance, the 3rd transistor, the 12 resistance; The 11 resistance, the 4th transistor, wherein; The grid of said transistor seconds electrically connects the collector electrode of a said NPN type triode through the 6th resistance, and the drain electrode of transistor seconds electrically connects standby module power down railway voltage source at first, the source ground of transistor seconds through the 8th resistance; Said the 3rd transistor electrically connects the collector electrode of a said NPN type triode through the 7th resistance; The 3rd transistor drain is often opened sources, the 3rd transistorized source ground through the system Chang Kaimo piece that the tenth resistance electrically connects the generation of standby module; The 4th transistorized grid electrically connects the collector electrode of a said NPN type triode through the 12 resistance, and the 4th transistor drain electrically connects the 3rd standby voltage that the standby module produces, the 4th transistorized source ground through the 11 resistance.
More excellent, said transistor seconds, the 3rd transistor and the 4th transistor are the enhancement mode nmos pass transistor.
Another purpose of the utility model is to provide a kind of receiving terminal for digital television that comprises above-mentioned power switch circuit, and said receiving terminal for digital television is STB, digital TV integrated machine or network protocol television.
Adopt technical scheme disclosed in the utility model, reduced the power consumption of power switch circuit, simultaneously, this circuit has favorable compatibility.
Description of drawings
Fig. 1 is the power switch circuit structured flowchart that the utility model provides;
Fig. 2 is the structural representation of the power switch circuit that provides of the utility model.
Embodiment
For the purpose, technical scheme and the advantage that make the utility model is clearer,, the utility model is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.
When standby module when power down railway voltage source V1 powers at first, the power down negative pulse produces circuit B1 output positive pulse; When the power down railway voltage source V1 power down at first of standby module, the power down negative pulse produces circuit B1 output negative pulse.
The standby module is power down railway voltage source V1 powered on moment at first; The power down negative pulse produces the positive pulse of circuit B1 generation can pass through negative pulse voltage clamp and forward bias circuit B2, and the negative pulse of power down moment generation is clamped at a constant voltage with protection first order switching circuit B3 by negative pulse voltage clamp and forward bias circuit B2.When system's operate as normal, negative pulse voltage clamp and forward bias circuit B2 provide the bias voltage of conducting and guarantee its conducting for first order switching circuit B3.
First order switching circuit B3 plays the effect of reverser.
Voltage delay circuit B4; To the non-shutoff maximum supply power of non-standby module voltage; Be that the Chang Kaimo of system piece is often opened sources Vx and delayed time; With guarantee powered on moment its less than standby module power down railway voltage source V1 at first, voltage delay circuit B4 inner packet contains big electric capacity simultaneously, to provide lasting voltage to reach second level switching circuit B6 conducting in power down or standby moment;
Voltage selecting circuit B5; Select input system Chang Kaimo piece often to open sources Vx and standby module the maximum of power down railway voltage source V1 at first: the powered on moment output voltage is standby module power down railway voltage source V1 at first; Output voltage is that power down railway voltage source V1 and the Chang Kaimo of system piece are often opened the maximum among the sources Vx to the standby module at first during operate as normal; Power down moment and standby moment output voltage be the standby module at first power down railway voltage source V1 voltage and the Chang Kaimo of system piece often open the maximum among the sources Vx, output voltage is that the Chang Kaimo of system piece is often opened sources Vx under the holding state.
Second level switching circuit B6 comprises at least one switching tube and a dummy load, specifically can be as required, and switching tube is set to triode or metal-oxide-semiconductor, and dummy load is a resistance.
Its course of work is: at system's powered on moment, standby module power down railway voltage source V1 at first produces positive pulse control signal of circuit B1 generation through the power down negative pulse, and through negative pulse voltage clamp and forward bias circuit B2.This moment, negative pulse voltage clamp and forward bias circuit B2 did not work, and positive pulse is transferred to the signal input part of first order switching circuit B3.Simultaneously; System Chang Kaimo piece often opens sources Vx because the time-lag action of voltage delay circuit B4; Always postpone in standby module power down railway voltage source V1 arrival at first voltage selecting circuit B5; After the Chang Kaimo of system piece was often opened sources Vx and standby module power down railway voltage source V1 arrival at first voltage selecting circuit B5 like this, the module of the standby always of output is power down railway voltage source V1 at first, so just avoids second level switching circuit B6 powered on moment conducting.Simultaneously, positive pulse control first order switching circuit B3 conducting, output low level, thus second level switching circuit B6 is turn-offed, second level switching circuit B6 does not work.
In system's power down or standby moment; Standby module power down railway voltage source V1 at first produces negative pulse control signal of circuit B1 generation through the power down negative pulse; And the negative pulse control signal is clamped at a fixed voltage value through negative pulse voltage clamp and forward bias circuit B2, with protection first order switching circuit B3.Voltage selecting circuit B5 through voltage delay circuit B4 continue output standby module at first power down railway voltage source V1 and the Chang Kaimo of system piece often open sources Vx the maximum among the two, the electric charge in voltage delay circuit B4 discharges fully.Negative pulse control signal control first order switching circuit B3 is by the output high level, and level value is that power down railway voltage source V1 and the Chang Kaimo of system piece are often opened sources Vx the maximum among the two to the standby module at first.Second level switching circuit B6 conducting this moment is also started working.If be system's power down, then the ON time of second level switching circuit B6 can be adjusted through the delay time of adjustment voltage delay circuit B4; If be system standby, then the stable system Chang Kaimo piece of voltage selecting circuit B5 output is often opened sources Vx and is controlled second level switching circuit B6 conducting, thereby makes the dummy load work among the switching circuit B6 of the second level.After dummy load is started working, a low resistance loop respectively is provided for the shunt capacitance (not shown among Fig. 2) of the supply power voltage of standby module 20, makes the shunt capacitance repid discharge, reduced the voltage that pours in down a chimney under the holding state simultaneously again.Whole process be equivalent to the standby module power rail parallel connection the dummy load of " dynamically " (this resistance can be adjusted according to actual conditions), consumed power not when system's operate as normal, this resistance works when system's power down or standby.
Below in conjunction with Fig. 2, this power switch circuit is specifically described.
The power down negative pulse produces circuit B1 and comprises the first diode D1; First resistance R 1; The positive pole of second capacitor C 2 and the 3rd resistance R 3, the first diode D1 electrically connects standby module power down railway voltage source V1 at first, and negative pole is through first resistance R, 1 ground connection; One end of second capacitor C 2 connects the negative pole of the first diode D1, and the other end is through the 3rd resistance R 3 ground connection.
Negative pulse voltage clamp and forward bias circuit B2 comprise second resistance R, 2, the four resistance R 4 and the second diode D2, and wherein, an end of said second resistance R 2 connects standby module 20 power down railway voltage source V1 at first, and the other end is through the 3rd resistance R 3 ground connection; One end of the 4th resistance R 4 connects second resistance R 2 and the 3rd resistance R 3, and the other end connects the second diode D2 negative pole, the plus earth of the said second diode D2.
First order switching circuit B3 comprises a NPN type triode Q1, and the base stage of the 5th resistance R 5, the one NPN type triode Q1 electrically connects the negative pole and second resistance R 2 of the second diode D2, and collector electrode electrically connects the 5th resistance R 5, grounded emitter.
Voltage delay circuit B4 comprises the 9th resistance R 9; The 4th diode D4 and the 3rd capacitor C 3; Wherein, One end of the 9th resistance R 9 electrically connects the Chang Kaimo of system piece and often opens sources VX, and the other end electrically connects the positive pole of the 4th diode D4, and the negative pole of the 4th diode D4 is through the 3rd capacitor C 3 ground connection.
Voltage selecting circuit B5 comprises the 3rd diode D3, and the positive pole of the 3rd diode D3 connects standby module power down railway voltage source V1 at first, and negative pole connects negative pole and the 5th resistance R 5 of the 4th diode D4.
Second level switching circuit B6 comprises the 6th resistance R 6, the eight resistance R 8, transistor seconds Q2, the 7th resistance R 7; The tenth resistance R 10, the three transistor Q3, the 12 resistance R 12; The 11 resistance R 11, the four transistor Q4, wherein; The grid of transistor seconds Q2 is through the collector electrode of the 6th resistance R 6 electric connections the one NPN type triode Q1, and the drain electrode of transistor seconds Q2 electrically connects standby modules power down railway voltage source V1 at first, the source ground of transistor seconds Q2 through the 8th resistance R 8; The 3rd transistor Q3 electrically connects the collector electrode of a NPN type triode Q1 through the 7th resistance R 7; The drain electrode of the 3rd transistor Q3 is often opened sources V2, the source ground of the 3rd transistor Q3 through the system Chang Kaimo piece that the tenth resistance R 10 electrically connects 20 generations of standby module; The grid of the 4th transistor Q4 electrically connects the collector electrode of a NPN type triode Q1 through the 12 resistance R 12; The drain electrode of the 4th transistor Q4 electrically connects the 3rd standby voltage V3 that standby module 20 produces, the source ground of the 4th transistor Q4 through the 11 resistance R 11.
The course of work of entire circuit is specific as follows:
When standby module when power down railway voltage V1 is begun to rise by 0V at first when standby wakeup (system power on or); Because second capacitor C, 2 voltage can't be suddenlyd change; Cause by the first diode D1 first resistance R, 1, the second capacitor C 2; The power down negative pulse that the 3rd resistance R 3 is formed produces circuit B1 and produces a positive pulse voltage, drives a NPN type triode Q1 through the 4th resistance R 4.At this moment, if system is a standby wakeup, then the existence of the 3rd capacitor C 3 two ends equals the voltage that Vx deducts the 4th diode D4 conduction voltage drop; If system re-powers, then because the 9th resistance R Chang Kaimo of 9 pairs of systems piece is often opened the time-lag action of sources Vx, the existence of the 3rd capacitor C 3 two ends equals the standby module voltage of power down railway voltage V1 at first.No matter is standby wakeup this time or re-power, and the positive pulse that a NPN type triode Q1 all can be produced is urged to saturation conduction, and its emitter current potential is 0V.At this moment as the transistor seconds Q2 of second level switching circuit B6; The 3rd transistor Q3; The 4th transistor Q4 all ends; Dummy load the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12 are in and disconnect state, therefore do not produce power consumption.
When the railway voltage of the power down at first V1 of standby module 20 is begun to descend by normal voltage (when system's power down or standby); Because second capacitor C 2 has been full of before the power down; And second capacitor C, 2 voltage can't be suddenlyd change, therefore by the first diode D1, and first resistance R 1; Second capacitor C 2; The power down negative pulse that the 3rd resistance R 3 is formed produces circuit B1 and produces a negative pulse voltage, and the clamper through the second diode D2 to make negative pulse voltage be the conduction voltage drop of the second diode D2, this voltage drives a NPN type triode Q1 through the 4th resistance R 4 to be ended.At this moment; Because before the power down railway voltage source V1 decline at first of standby module, the 3rd capacitor C 3 also has been full of electricity, and a NPN type triode Q1 ends; So second triode Q2 among the switching circuit B6 of the second level; The 3rd triode Q3, the equal conducting of the 4th triode Q4, dummy load the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12 are in on-state.If system is power down at this moment; Then charge stored is released and finishes in the second triode Q2 among the second level switching circuit B6, the 3rd triode Q3, the 4th triode Q4 conducting to the always three capacitor C 3; The dummy load that is switched on during this period the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12 have been accelerated the power down railway voltage source V1 at first of the standby module in the power rail; System Chang Kaimo piece is often opened sources V2; The 3rd standby voltage V3 goes up the discharge of shunt capacitance, has therefore played the effect of " dynamically " dummy load; If system is holding state at this moment; Then the second triode Q2 among the second level switching circuit B6, the 3rd triode Q3, the 4th triode Q4 can be driven conducting by the maximum supply power voltage Vx of system always; Dummy load this moment the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12 can drag down power rail, and (the standby module is power down railway voltage source V1 at first; System Chang Kaimo piece is often opened sources V2; The 3rd standby voltage V3) pours in down a chimney voltage on, thereby improved the stability that system standby is waken up.
In concrete the realization, can control a NPN type triode Q1 ON time through the appearance value size of adjusting second capacitor C 2 and the 3rd capacitor C 3.More greatly then power down moment the one NPN type triode Q1 is long more deadline for second capacitor C 2 and the 3rd capacitor C 3; Then the ON time of the second triode Q2 among the second level switching circuit B6, the 3rd triode Q3, the 4th triode Q4 is long more, and dummy load (the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12) operating time is long more.Can be according to standby power threshold voltage when the size of power down railway voltage V1 is adjusted a NPN type triode Q1 conducting at first; Requirement is when system's operate as normal, the saturation conduction time of the second triode Q2 among a NPN type triode Q1, the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12 road B6, the 3rd triode Q3, the 4th triode Q4.The diode of same model is selected in the 3rd diode D3 and the 4th diode D4 suggestion; Transistor seconds Q2, the 3rd transistor Q3 and the 4th transistor Q4 are the enhancement mode nmos pass transistor.
The power switch circuit that adopts the utility model embodiment to be provided; Following advantage is arranged: at first; In the quickening power rail power down that has realized that resistance (the 6th resistance R 6, the 8th resistance R 8, the 7th resistance R 7, the tenth resistance R the 10, the 11 resistance R the 11, the 12 resistance R 12) should play as dummy load; Reduce the standby module and pour in down a chimney under the prerequisite of voltage effect, solved dummy load also problem of consumed power when system's operate as normal;
Simultaneously, this circuit has favorable compatibility, does not influence the shunt capacitance value size of system power supply distribution network, does not change existing power supply conversion plan and standby implementation.
Moreover this circuit has good autgmentability, can realize one or more " dynamically " dummy load as required.
Last this circuit has good debugging property, and a plurality of device parameters can be made amendment according to actual design and debugging situation.
Another purpose of the utility model is to provide a kind of receiving terminal for digital television, and described receiving terminal for digital television comprises the power switch circuit in the previous embodiment.Concrete, said receiving terminal for digital television be STB, digital TV integrated machine or network protocol television (Internet Protocol Television, IPTV).
The above is merely the preferred embodiment of the utility model; Not in order to restriction the utility model; Any modification of being done within all spirit and principles at the utility model, be equal to replacement and improvement etc., all should be included within the protection range of the utility model.
Claims (10)
1. power switch circuit, it connects standby module, it is characterized in that; Said power switch circuit comprises that the power down negative pulse produces circuit; Negative pulse voltage clamp and forward bias circuit, first order switching circuit, voltage delay circuit; Voltage selecting circuit; Second level switching circuit, the standby module is power down railway voltage source at first, and system Chang Kaimo piece is often opened sources; Wherein: the signal input part that said power down negative pulse produces circuit electrically connects said second level switching circuit in power down railway voltage source at first through the standby module, and the signal output part that said power down negative pulse produces circuit electrically connects said first order switching circuit first signal input part through negative pulse voltage clamp and forward bias circuit; Said first order switching circuit signal output part electrically connects said second level switching circuit; Said system Chang Kaimo piece is often opened sources electrically connects said voltage selecting circuit through the voltage delay circuit first signal input part; The secondary signal input of said voltage selecting circuit electrically connects standby module power down railway voltage source at first, and the signal output part of voltage selecting circuit electrically connects the secondary signal input of said first order switching circuit; Said second level switching circuit electrically connects said standby module.
2. power switch circuit as claimed in claim 1 is characterized in that, said power down negative pulse produces circuit and comprises first diode; First resistance, second electric capacity and the 3rd resistance, wherein; The positive pole of said first diode electrically connects standby module power down railway voltage source at first; Negative pole is through first grounding through resistance, and an end of second electric capacity connects the negative pole of first diode, and the other end is through the 3rd grounding through resistance.
3. according to claim 1 or claim 2 power switch circuit; It is characterized in that; Said negative pulse voltage clamp and forward bias circuit comprise second resistance, the 4th resistance and second diode, wherein; One end of said second resistance connects standby module power down railway voltage source at first, and the other end is through the 3rd grounding through resistance; One end of the 4th resistance connects second resistance and the 3rd resistance, and the other end connects second diode cathode, the plus earth of said second diode.
4. power switch circuit as claimed in claim 3; It is characterized in that; Said first order switching circuit comprises a NPN type triode, the 5th resistance, and the base stage of a said NPN type triode electrically connects the negative pole and second resistance of second diode; Collector electrode electrically connects the 5th resistance, grounded emitter.
5. like claim 1 or 4 described power switch circuits; It is characterized in that said voltage delay circuit comprises the 9th resistance, the 4th diode and the 3rd electric capacity; Wherein, One end of said the 9th resistance electrically connects the Chang Kaimo of system piece and often opens sources, and the other end electrically connects the positive pole of the 4th diode, and the negative pole of the 4th diode is through the 3rd capacity earth.
6. power switch circuit as claimed in claim 5; It is characterized in that; Said voltage selecting circuit comprises the 3rd diode, and the positive pole of said the 3rd diode connects standby module power down railway voltage source at first, and negative pole connects the negative pole and the 5th resistance of the 4th diode.
7. power switch circuit as claimed in claim 5 is characterized in that, said second level switching circuit comprises the 6th resistance; The 8th resistance, transistor seconds, the 7th resistance; The tenth resistance, the 3rd transistor, the 12 resistance; The 11 resistance, the 4th transistor, wherein; The grid of said transistor seconds electrically connects the collector electrode of a said NPN type triode through the 6th resistance, and the drain electrode of transistor seconds electrically connects standby module power down railway voltage source at first, the source ground of transistor seconds through the 8th resistance; Said the 3rd transistor electrically connects the collector electrode of a said NPN type triode through the 7th resistance; The 3rd transistor drain is often opened sources, the 3rd transistorized source ground through the system Chang Kaimo piece that the tenth resistance electrically connects the generation of standby module; The 4th transistorized grid electrically connects the collector electrode of a said NPN type triode through the 12 resistance, and the 4th transistor drain electrically connects the 3rd standby voltage that the standby module produces, the 4th transistorized source ground through the 11 resistance.
8. power switch circuit as claimed in claim 7 is characterized in that, said transistor seconds, the 3rd transistor and the 4th transistor are the enhancement mode nmos pass transistor.
9. a receiving terminal for digital television is characterized in that, comprises any described power switch circuit like claim 1-8.
10. receiving terminal for digital television as claimed in claim 9 is characterized in that, said receiving terminal for digital television comprises STB or digital TV integrated machine or network protocol television.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200798210U CN202121562U (en) | 2011-03-24 | 2011-03-24 | Power switch circuit and digital television receiving terminal |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200798210U CN202121562U (en) | 2011-03-24 | 2011-03-24 | Power switch circuit and digital television receiving terminal |
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| CN202121562U true CN202121562U (en) | 2012-01-18 |
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| CN2011200798210U Expired - Fee Related CN202121562U (en) | 2011-03-24 | 2011-03-24 | Power switch circuit and digital television receiving terminal |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107340846A (en) * | 2017-08-31 | 2017-11-10 | 广东虹勤通讯技术有限公司 | The logic circuit and notebook computer of a kind of power down preventing |
| CN109510953A (en) * | 2018-11-29 | 2019-03-22 | 中国航空工业集团公司沈阳飞机设计研究所 | A kind of S separation vision signal is converted to the conversion circuit of composite video signal |
| CN110611354A (en) * | 2019-10-11 | 2019-12-24 | 苏州浪潮智能科技有限公司 | Discharging structure and charging and discharging structure |
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2011
- 2011-03-24 CN CN2011200798210U patent/CN202121562U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107340846A (en) * | 2017-08-31 | 2017-11-10 | 广东虹勤通讯技术有限公司 | The logic circuit and notebook computer of a kind of power down preventing |
| CN109510953A (en) * | 2018-11-29 | 2019-03-22 | 中国航空工业集团公司沈阳飞机设计研究所 | A kind of S separation vision signal is converted to the conversion circuit of composite video signal |
| CN110611354A (en) * | 2019-10-11 | 2019-12-24 | 苏州浪潮智能科技有限公司 | Discharging structure and charging and discharging structure |
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