CN207265888U - A kind of set-top box and its power circuit - Google Patents
A kind of set-top box and its power circuit Download PDFInfo
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- CN207265888U CN207265888U CN201721291634.2U CN201721291634U CN207265888U CN 207265888 U CN207265888 U CN 207265888U CN 201721291634 U CN201721291634 U CN 201721291634U CN 207265888 U CN207265888 U CN 207265888U
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Abstract
The utility model belongs to power technique fields, there is provided a kind of set-top box and its power circuit.In the utility model, by using the power circuit for including rectification filtering module, input sample module, the first output voltage sampling module, control module, switch module and voltage transformation module, during so that the input voltage of input sample module samples being higher than the first predeterminated voltage, control module controlling switch module is closed, so that voltage transformation module stops output charging voltage；And first the sampling of output voltage sampling module the first output sampled voltage when being higher than the second predeterminated voltage; control module controlling switch module is closed; so that voltage transformation module stops output charging voltage; so that electrical equipment and power circuit are protected in the input voltage or excessive output voltage of the power circuit; the functional reliability of power circuit is improved, solves the problems, such as that reliability existing for the power circuit of existing set-top box is low.
Description
Technical field
The utility model belongs to power technique fields, more particularly to a kind of set-top box and its power circuit.
Background technology
With the development of Interactive Internet TV IPTV, set-top box is used as in IPTV and traditional tv is matching used sets
Standby, its importance is self-evident.And as the power source of set-top box, the work of the power circuit of set-top box to set-top box plays
Vital effect.
However, in the power circuit of set-top box disclosed at present, the power circuit of existing set-top box is met with power grid
When lightning stroke, inputted to the input voltage of power circuit, and power circuit and exported to the output electricity of set-top box by power grid
Pressure can be raised drastically moment, and excessive input voltage and excessive output voltage are easy to cause power circuit and set-top box hair
Raw failure, so that power circuit and set-top box can not work, reduces the reliability of set-top box power circuit.
In conclusion the power circuit of existing set-top box there are reliability it is low the problem of.
Utility model content
The purpose of this utility model is to provide a kind of set-top box and its power circuit, it is intended to solves the electricity of existing set-top box
Source circuit there are reliability it is low the problem of.
The utility model is realized in this way a kind of power circuit, the power circuit includes：
Rectification filtering module, input sample module, the first output sampling module, control module, switch module and voltage
Modular converter；
The input terminal of the rectification filtering module receives supply voltage, the output terminal of the rectification filtering module with it is described defeated
Enter the first input end connection of the input terminal and the voltage transformation module of sampling module, the output of the input sample module
End is connected with the voltage end of the control module, the second input terminal of the voltage transformation module and the input of the switch module
End connection, the first output terminal and the second output terminal of the voltage transformation module are connected with electrical equipment, the voltage conversion
3rd input terminal of module is connected with the input terminal of the described first output sampling module, the output of the first output sampling module
End is connected with the signal input part of the control module, the control of the signal output part of the control module and the switch module
End connection, the output terminal of the switch module and the ground terminal of the control module are connected to equipotential end altogether；
The rectification filtering module exports direct current after being filtered rectification to the supply voltage；The control module will
The DC inverter is exchange electricity output to the voltage transformation module, and the voltage transformation module carries out the alternating current
Voltage conversion, and charging voltage is exported to the electrical equipment；The input sample module samples the direct current, and
When input sample voltage is higher than the first predeterminated voltage, the first feedback signal, the control module are inputted to the control module
The switch module is controlled to be closed according to first feedback signal, so that voltage transformation module stopping is defeated
Go out the charging voltage；The first output sampling module samples the alternating current to export the first output sampling electricity
Pressure, and when the described first output sampled voltage is higher than the second predeterminated voltage, the second feedback signal is exported to the control module,
The control module controls the switch module to be closed according to second feedback signal, so that the voltage turns
Block is changed the mold to stop exporting the charging voltage.
The another object of the utility model is to provide a kind of set-top box, and the set-top box includes above-mentioned power circuit.
In the utility model, sampled by using including rectification filtering module, input sample module, the first output voltage
Module, control module, the power circuit of switch module and voltage transformation module, rectification filtering module filter supply voltage
Direct current is exported after ripple rectification；DC inverter is exchange electricity output to voltage transformation module, voltage conversion mould by control module
Block carries out voltage conversion to alternating current, and exports charging voltage to electrical equipment；Input sample module samples direct current,
And when input sample voltage is higher than the first predeterminated voltage, the first feedback signal is inputted to control module, control module is according to the
One feedback signal controlling switch module is closed, so that voltage transformation module stops output charging voltage；First is defeated
Go out sampling module to sample alternating current to export the first output sampled voltage, and be higher than second in the first output sampled voltage
During predeterminated voltage, to control module export the second feedback signal, control module according to the second feedback signal controlling switch module at
In closed mode, so that voltage transformation module stops output charging voltage, the input voltage when the power circuit is reached with this
Or output voltage it is excessive when, the purpose protected to electrical equipment and power circuit, the work for improving power circuit can
By property, solve the problems, such as that the power circuit of existing set-top box is low there are reliability.
Brief description of the drawings
Fig. 1 is the modular structure schematic diagram for the power circuit that one embodiment of the utility model is provided；
Fig. 2 is the modular structure schematic diagram for the power circuit that another embodiment of the utility model is provided；
Fig. 3 is the electrical block diagram for the power circuit that one embodiment of the utility model is provided.
Embodiment
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, is further elaborated the utility model.It should be appreciated that specific embodiment described herein is only explaining
The utility model, is not used to limit the utility model.
It is described in detail below in conjunction with realization of the specific attached drawing to the utility model：
Fig. 1 shows the modular structure for the power circuit 10 that one embodiment of the utility model is provided, for convenience of description,
Part related to the present embodiment is illustrate only, details are as follows：
As shown in Figure 1, the power circuit 1 that the utility model embodiment is provided includes：Rectification filtering module 10, input are adopted
Egf block 20, first exports sampling module 30, control module 40, switch module 50 and voltage transformation module 60.
Wherein, the input terminal of rectification filtering module 10 receives supply voltage, the output terminal of rectification filtering module 10 and input
The connection of the first input end of the input terminal of sampling module 20 and voltage transformation module 60, the output terminal of input sample module 20 with
The voltage end connection of control module 40, the second input terminal of voltage transformation module 60 are connected with the input terminal of switch module 50, electricity
The first output terminal and the second output terminal for pressing modular converter 60 are connected with electrical equipment (not shown), voltage transformation module
60 the 3rd input terminal is connected with the input terminal of the first output sampling module 30, the output terminal of the first output sampling module 30 and control
The signal input part connection of molding block 40, the signal output part of control module 40 are connected with the control terminal of switch module 50, switch
The output terminal of module 50 is connected to equipotential end altogether with the ground terminal of control module 40.
Specifically, rectification filtering module 10 exports direct current after rectification is filtered to supply voltage；Control module 40 will
DC inverter is exchange electricity output to voltage transformation module 60, and voltage transformation module 60 carries out alternating current voltage conversion, and
Charging voltage is exported to electrical equipment；Input sample module 20 samples direct current, and in input sample voltage higher than the
During one predeterminated voltage, the first feedback signal is inputted to control module 40, control module 40 is according to the first feedback signal controlling switch
Module 50 is closed, so that voltage transformation module 60 stops output charging voltage；First output 30 pieces of mould of sampling is right
Alternating current is sampled to export the first output sampled voltage, and when the first output sampled voltage is higher than the second predeterminated voltage,
The second feedback signal is exported to control module 40, control module 40 is according to the second feedback signal controlling switch module 50 and closes
State, so that voltage transformation module 60 stops output charging voltage.
It should be noted that in the present embodiment, supply voltage is exported by power grid, i.e., rectification filtering module 10 is defeated
Entering end to be connected with firewire and zero curve, that is to say, that the supply voltage is 220V alternating currents, and the direct current that direct current is 220V,
It is the alternating current after 50 inversion of switch module to export to the alternating current of voltage transformation module 60, and charging voltage is inverse to this
The alternating current obtained after change carries out the alternating current after voltage transformation；In addition, the first predeterminated voltage and the second predeterminated voltage are bases
Circuit needs what is be configured, is not particularly limited herein.
It is worth noting that, in the present embodiment, the first feedback signal and the second feedback signal can be feedback voltage, also may be used
Think height pulse feedback signal, it needs to feed back the worked of the output sampling module 30 of input sample module 20 and first
Journey, does not do concrete restriction to its implementation herein.
In the present embodiment, direct current is sampled by using input sample module, or mould is sampled with the first output
Block samples alternating current, and when the sampled result of direct current is higher than the first predeterminated voltage, which is carried out defeated
Enter overvoltage protection, or when the sampled result of alternating current is higher than the second predeterminated voltage, output overvoltage guarantor is carried out to the power circuit
Shield, realizes the input and output overvoltage protection of power circuit, improves the functional reliability of power circuit.
Further, as one preferred embodiment of the utility model, as shown in Fig. 2, the power circuit 1 further includes second
Export sampling module 70.
Wherein, this second output sampling module 70 first input end and the second input terminal with voltage transformation module 60
First output terminal connects, and the output terminal of the second output sampling module 60 is connected with the feedback end of control module 40.
Specifically, the second output sampling module 70 samples charging voltage to export the second output sampled voltage, and
When the second output sampled voltage is higher than three predeterminated voltages, the 3rd feedback signal, control module 40 are exported to control module 40
It is closed according to the 3rd feedback signal controlling switch module 50, so that voltage transformation module 60 stops to electrical equipment
Charging.
It should be noted that in the present embodiment, the 3rd feedback signal can be feedback voltage, or height pulse is anti-
Feedback signal, it needs the course of work for feeding back the second output sampling module 70, its implementation is not done herein
Concrete restriction；In addition, the first predeterminated voltage and the second predeterminated voltage need to be configured according to circuit, do not do herein specific
Limitation.
In the present embodiment, charging voltage is sampled by using the second output sampling module, and in sampled result
During higher than three predeterminated voltages, output over-voltage protection is carried out to the power circuit, realizes the input and output overvoltage of power circuit
Protection, further increases the functional reliability of power circuit.
Further, as one preferred embodiment of the utility model, as shown in Fig. 2, the power circuit further includes protection
Module 80.
Wherein, the input terminal of protection module 80 receives supply voltage, the output terminal and rectification filtering module of protection module 80
10 input terminal connection.
Specifically, protection module 80 carries out supply voltage over-pressed protective treatment, and the supply voltage after processing is exported
To rectification filtering module 10.
In the present embodiment, over-pressed protective treatment carries out supply voltage using protection module 80 so that the power circuit
Lightning stroke is being run into when causing supply voltage moment to raise under state, and supply voltage is being absorbed, it is elevated to reduce moment
Supply voltage, prevents power circuit to be damaged.
Further, as one preferred embodiment of the utility model, as shown in figure 3, input sample module includes：
First resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the first capacitance C1, the first silicon-controlled IC1
And first switching element Q1.
Wherein, the first end of first resistor R1 is the input terminal of input sample module, the second end of first resistor R1 and the
The first end connection of two resistance R2, the second end of second resistance R2 are connected with the first end of 3rd resistor R3,3rd resistor R3's
Second end is connected with the control terminal of the first end of the 4th resistance R4, the first end of the first capacitance C1 and the first silicon-controlled IC1, the
The cathode of one silicon-controlled IC1 is connected with the control terminal of first switching element Q1, and the anode of the first silicon-controlled IC1 connects equipotential end,
The output terminal of first switching element Q1 is the output terminal of input sample module, and the second end of the 4th resistance R4 is with the first capacitance C1's
Second end is connected to equipotential end altogether.
It should be noted that in the present embodiment, first switching element Q1 can use NPN type triode to realize, the NPN type
Base stage, collector and the emitter of triode are respectively control terminal, input terminal and the output terminal of first switching element Q1；
Certainly it will be appreciated by persons skilled in the art that first switching element Q1 can also use metal-oxide-semiconductor etc. to realize, do not make to have herein
Body limits.
Further, capacitance C8 is further included as one preferred embodiment of the utility model, the input sample module, the electricity
The first segment for holding C8 is connected with the output terminal of first switching element Q1, and the second end of capacitance C8 is connected in equipotential end, it is used
It is powered in the voltage end to control module.
Further, as one preferred embodiment of the utility model, as shown in figure 3, the first output sampling module includes：
First diode D1, the first storage capacitor C2, the first zener diode D2 and the 5th resistance R5.
Wherein, the anode of the first diode D1 for first output sampling module input terminal, the cathode of the first diode D1
It is connected with the cathode of the two pole D2 of first end and the first voltage stabilizing of the first storage capacitor C2, the second end of the first storage capacitor C2 connects
Equipotential end is connected to, the anode of the first zener diode D2 is connected with the first end of the 5th resistance R5, and the second of the 5th resistance R5
Hold as the output terminal of the first output sampling module.
Further, as one preferred embodiment of the utility model, as shown in figure 3, switch module includes：
Second diode D3, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8 and second switch element Q2.
Wherein, the first end of the 6th resistance R6 connects the control terminal to form switch module altogether with the first end of the 7th resistance R7,
The second end of 6th resistance R6 is connected with the cathode of the second diode D3, and the of the anode of the second diode D3 and the 7th resistance R7
The control terminal connection at two ends, the first end of the 8th resistance R8 and second switch element Q2, the output terminal of second switch element Q2
For the output terminal of switch module, the Q2 input terminals of second switch element are the input terminal of switch module, the second of the 8th resistance R5
End is connected to equipotential end.
It should be noted that in the present embodiment, second switch element Q2 can use nmos pass transistor to realize, the NMOS is brilliant
Grid, drain electrode and the source electrode of body pipe are respectively control terminal, input terminal and the output terminal of second switch element Q2.Certain ability
Field technique personnel are it is understood that second switch element Q2 can also use NPN type triode, PNP type triode, PMOS brilliant
Body pipe etc. is realized, is not specifically limited herein.
Further, as one preferred embodiment of the utility model, as shown in figure 3, control module includes control chip
U1。
Wherein, the voltage end of the voltage pin VDD of control chip U1 modules in order to control, the signal input of control chip U1 are drawn
The signal input part of foot RI modules in order to control, the signal output part of the controlling switch GATE of control chip U1 module in order to control, control
The feedback end of the feedback pin FB of coremaking piece modules 40 in order to control, module connects in order to control by the grounding pin GND of control chip U1
Ground terminal.
Further, as one preferred embodiment of the utility model, as shown in figure 3, the second output sampling module includes：
9th resistance R9, the tenth resistance R10, the 11st resistance R11, the 12nd resistance R12, the 13rd resistance R13, the tenth
Four resistance R13, the second capacitance C3, the second controllable IC2 and photoelectrical coupler IC3-A-B.
Wherein, the first end of the 9th resistance R9 for the second output sampling module first input end, the of the 9th resistance R9
Two ends are connected with the first end of the tenth resistance R10 and the first end of photoelectrical coupler IC3-A-B, photoelectrical coupler IC3-A-B
Second end be connected with the cathode of the second end of the tenth resistance R10, the first end of the second capacitance C3 and the second silicon-controlled IC2,
The second end of second capacitance C3 is connected with the first end of the 11st resistance R11, the second end of the 11st resistance R11 and the 12nd electricity
Hinder the second end of R12, the first end of the 14th resistance R14, the first end of the 13rd resistance R13 and the second silicon-controlled IC2
Control terminal connects, and the first end of the 12nd resistance R12 is the second input terminal of the second output sampling module, the second silicon-controlled IC1
Anode and the second end of the 13rd resistance R13 and the second end of the 14th resistance R14 be connected to ground, photoelectrical coupler IC3- altogether
The 3rd end of A-B is the output terminal of the second output sampling module, and the 4th end and the equipotential end of photoelectrical coupler IC3-A-B connect
Connect.
Further, as one preferred embodiment of the utility model, as shown in Fig. 2, power circuit further includes filtering mould
Block 90.
Wherein, the first input end of filter module 90 is connected with 60 first output terminal of voltage transformation module, filter module 90
The second input terminal be connected with the second output terminal of voltage transformation module 60, the first output terminal of filter module 90 and second output
End is connected with electrical equipment.
Specifically, the charging voltage of 90 receiving voltage modular converter 60 of filter module output, and charging voltage is filtered
Charge after ripple to electrical equipment.
Further, inhaled as one preferred embodiment of the utility model, the filter module 90 including the first spike
Receive circuit and filter circuit.
Wherein, the first input end of the first spike absorbing circuit is the first input end of filter module 90, and first is sharp
Second input terminal of peak pulse absorption circuit and the second input terminal of filter circuit connect the second input to form filter module 90 altogether
End, the output terminal of the first spike absorbing circuit and the first input end of filter circuit connect, the first output of filter circuit
The first output terminal for filter module 90 is held, the second output terminal of filter circuit is the second output terminal of filter module 90.
Specifically, the charging voltage that the first spike absorbing circuit exports voltage transformation module 60 carries out spike
Absorb, and filter circuit is that the charging voltage after spike absorbs is filtered to handle to eliminate in charging voltage
Noise jamming.
Further, as one preferred embodiment of the utility model, as shown in figure 3, the first spike absorbing circuit
Including resistance R15, resistance R16, capacitance C4, capacitance C5, diode D4 and diode D5.
Wherein, the first end of resistance R15 and first end, the anode of diode D4 and the sun of diode D5 of resistance R16
Extremely connect the first input end to form the first spike absorbing circuit altogether, the first end of resistance R15 and the second end of resistance R16 with
And the first end connection of capacitance C4, the second end of capacitance C4 and the cathode of diode D4, the cathode and capacitance C5 of diode D5
First end connect the output terminal to form the first spike absorbing circuit altogether, the second end of capacitance C5 is that the first spike absorbs
Second input terminal of circuit.
Further, as one preferred embodiment of the utility model, as shown in figure 3, filter circuit includes the first electromagnetism
Disturbance means L1, resistance R17, photodiode D6 and capacitance C6.
Wherein, the first end and second end of the first electromagnetic interference device L1 is respectively the first input end and of filter circuit
Two input terminals, the 3rd end of the first electromagnetic interference device L1 and the first end of resistance R17 and the first end of capacitance C6 connect shape altogether
Into the first output terminal of filter circuit, the 4th end of the first electromagnetic interference device L1 and the anode and capacitance of photodiode D6
The second end of C6 connects the second output terminal to form filter circuit altogether, and the 3rd end of resistance R17 and the cathode of photodiode D6 connect
Connect.
Further, as one preferred embodiment of the utility model, as shown in figure 3, the power circuit further includes second
Spike absorbing circuit.
Wherein, the input terminal of the second spike absorbing circuit is connected with the first input end of voltage transformation module 60,
The output terminal of the second spike absorbing circuit is connected with the second input terminal of voltage transformation module 60.
Specifically, the second spike absorbing circuit is used to carry out point to the alternating current after 50 inversion of switch module
Peak pulse absorption processing, to eliminate the noise signal in the alternating current.
Further, as shown in figure 3, the second spike absorbing circuit include capacitance C7, resistance R18, resistance R19,
Resistance R20, resistance R21 and diode D7.
Specifically, the first end of the first end of capacitance C7 and resistance R18 and the first end of resistance R19 connect altogether to be formed this
The input terminal of two spike absorbing circuits, second end and the second end of resistance R18, the second end of resistance R19, the electricity of capacitance C7
Hinder the first end of R20 and the first end of resistance R21 connects altogether, the second end of resistance R20 and the second end of resistance R21 and two poles
The cathode connection of pipe D7, the anode of diode D7 are the output terminal of the second spike absorbing circuit.
Further, as one preferred embodiment of the utility model, as shown in figure 3, the power circuit further includes electric current
Sampling module, the current sample module sample the electric current for flowing through second switch element Q2, in order to U1 pairs of control chip
The power circuit carries out overcurrent protection.
Wherein, which includes resistance R23, resistance R24, resistance R25 and resistance R26.
Specifically, the first end of the resistance R23 and first end of resistance R24, the first end of resistance R25 and resistance R26
First end is connected to the output terminal of second switch element Q2, the second end of resistance R23 and the second end and resistance of resistance R24 altogether
The second end of R25 is connected to equipotential end altogether, and the second end of resistance R26 is connected with the electric current induction end SEN of control chip U1.
Further, as one preferred embodiment of the utility model, as shown in figure 3, voltage transformation module includes：Transformation
Device T and resistance R22.
Wherein, the first end of the first armature winding of transformer T be voltage transformation module 60 first input end, transformer
The second end of the first armature winding of T is the second input terminal of voltage transformation module 60, the of the second armature winding of transformer T
One end is connected with the second end of resistance R22, and the first end of resistance R22 is the 3rd input terminal of voltage transformation module 60, transformer T
The second end of the second armature winding be connected with equipotential end, the first end and second end of the secondary windings of transformer T is respectively
The first output terminal and the second output terminal of voltage transformation module 0.
It should be noted that in the present embodiment, due to the operation principle of transformer T be according to armature winding and it is secondary around
Coil ratio between group, is high voltage by low voltage transition, or high voltage is converted to low-voltage, therefore, transformer T's
Voltage on secondary windings can be obtained by the proportionate relationship between the coil of the armature winding of transformer T and the coil of secondary windings
Know, therefore, when needing the charging voltage size to obtaining power circuit output, it is only necessary to the second armature winding of transformer T
On voltage sampled.
Further, as one preferred embodiment of the utility model, as shown in figure 3, protection module include fuse F and
Varistor RV.Wherein, the first end of fuse F is the input terminal of protection module, the second end of fuse F and varistor RV
First end connect the output terminal to form protection module altogether, the second end of varistor RV is connected with zero curve.
Specifically, when the 220V electric mains of input are within predetermined voltage range, the resistance value of varistor RV is big, protects
Dangerous silk F, which will not fuse, to be not turned on, when the 220V electric mains of input are higher by preset voltage value, varistor RV transient switchings,
Electric current in fuse F all flows through varistor RV, fuse F fusing, with protection power source circuit.
Further, as one preferred embodiment of the utility model, as shown in figure 3, rectification filtering module includes rectification
Unit and filter unit.
Wherein, the input terminal of rectification unit is the input terminal of rectification filtering module, and the output terminal of rectification unit and filtering are single
The input terminal connection of member, the output terminal of filter unit are the output terminal of rectifying and wave-filtering mould 10.
Specifically, the rectification of 220V electric mains is unidirectional Rectified alternating current by rectification unit, filter unit is to the unidirectional arteries and veins
Dynamic direct current is filtered for the first time, to eliminate the noise signal in unidirectional Rectified alternating current.
Further, as one preferred embodiment of the utility model, as shown in figure 3, rectification unit can use bridge-type whole
Current circuit realizes that filter unit can use EMC electromagnetic interference circuits to realize, and on bridge rectifier and EMC electromagnetic interferences
The related work principle of circuit, refers to the prior art, is not particularly limited herein.
The operation principle of power circuit provided by the utility model is made specifically by taking the circuit shown in Fig. 3 as an example below
Bright, details are as follows：
As shown in figure 3, when the input voltage of 1 front end receiver of power circuit is normal, rectification circuit is by the input voltage
Output is extremely defeated to this by resistance input sample module, input sample mould sampling resistor R1, R2, R3 and R4 in the block after rectification
Enter voltage to be sampled, when the voltage of sampling is less than the conducting voltage of the first silicon-controlled IC1, control chip U1 controls second are opened
Close element Q2 conducting, the DC inverter after rectifier circuit rectifies is alternating current by second switch element Q2, the alternating current via
Transformer T exports charging voltage after carrying out voltage conversion, and the charging voltage is by spike absorbing circuit and filter circuit
After clutter filters out, export to electrical equipment, to charge to electrical equipment.And when the input voltage of 1 front end receiver of power circuit
When increasing because of a variety of causes, input sample mould sampling resistor R1, R2, R3 and R4 in the block sample obtained input sample
Voltage increases, when the input sample voltage is higher than the conducting voltage of the first silicon-controlled IC1, the first silicon-controlled IC1 conductings, and then
By the voltage pull-down of the voltage end VDD of control chip U1 so that control chip U1 control second switch element Q2 by, into
And make it that the path between transformer T and second switch element Q2 disconnects, to realize the input overvoltage protection to power circuit 1.
Further, since power circuit 1 is there are output overvoltage risk, and the charging voltage and transformer T that power circuit 1 exports
The second armature winding voltage it is proportional, therefore, by diode D1, capacitance C5, zener diode D2 and resistance R5
First output sampling module of composition samples the alternating current on the second armature winding of transformer T, is obtained when sampling
First output sampled voltage be higher than zener diode D2 breakdown voltage when, zener diode D2 breakdown, and by resistance R5 to
Control chip U is fed back, and control chip U1 controls second switch element Q2 by so that transformer according to feedback result
Path between T and second switch element Q2 disconnects, to realize the output over-voltage protection to power circuit 1.
Further, can be by the electricity in the second output sampling module when carrying out output over-voltage protection to power circuit 1
Hinder R12, resistance R13 and resistance R14 carry out partial pressure to the charging voltage of output, when the charging voltage of output raises for some reason, and
When can damage power circuit 1, resistance R12, resistance R13 and resistance R14 carry out partial pressure to the charging voltage of output can equally rise
Height, when the partial pressure is more than the conducting voltage of the second silicon-controlled IC2, the phototriode in photoelectrical coupler U2 shines, with to
Control chip U1 feedback charging voltage it is excessive, at this time control chip U1 according to feedback result control second switch element Q2 by,
So that the path between transformer T and second switch element Q2 disconnects, to realize that the output overvoltage to power circuit 1 is protected
Shield.
Further, the utility model additionally provides a kind of set-top box, which includes power circuit 1.Need to illustrate
, the power circuit 1 shown in power circuit 1 and Fig. 1 to Fig. 3 provided by the utility model embodiment is identical,
The concrete operating principle of power circuit 1 in the set-top box that the embodiment of the present invention is provided, refers to previously with regard to Fig. 1 to Fig. 3
Detailed description, details are not described herein again.
In the utility model, sampled by using including rectification filtering module, input sample module, the first output voltage
Module, control module, the power circuit of switch module and voltage transformation module, rectification filtering module filter supply voltage
Direct current is exported after ripple rectification；DC inverter is exchange electricity output to voltage transformation module, voltage conversion mould by control module
Block carries out voltage conversion to alternating current, and exports charging voltage to electrical equipment；Input sample module samples direct current,
And when input sample voltage is higher than the first predeterminated voltage, the first feedback signal is inputted to control module, control module is according to the
One feedback signal controlling switch module is closed, so that voltage transformation module stops output charging voltage；First is defeated
Go out sampling module to sample alternating current to export the first output sampled voltage, and be higher than second in the first output sampled voltage
During predeterminated voltage, to control module export the second feedback signal, control module according to the second feedback signal controlling switch module at
In closed mode, so that voltage transformation module stops output charging voltage, the input voltage when the power circuit is reached with this
Or output voltage it is excessive when, the purpose protected to electrical equipment and power circuit, the work for improving power circuit can
By property, solve the problems, such as that the power circuit of existing set-top box is low there are reliability.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
All any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model
Protection domain within.
Claims (10)
1. a kind of power circuit, it is characterised in that the power circuit includes：
Rectification filtering module, input sample module, the first output sampling module, control module, switch module and voltage conversion
Module；
The input terminal of the rectification filtering module receives supply voltage, and the output terminal of the rectification filtering module is adopted with the input
The first input end of the input terminal of egf block and the voltage transformation module connect, the output terminal of the input sample module with
The voltage end connection of the control module, the second input terminal of the voltage transformation module connect with the input terminal of the switch module
Connect, the first output terminal and the second output terminal of the voltage transformation module are connected with electrical equipment, the voltage transformation module
The 3rd input terminal with described first output sampling module input terminal be connected, it is described first output sampling module output terminal and
The signal input part connection of the control module, the signal output part of the control module and the control terminal of the switch module connect
Connect, the output terminal of the switch module and the ground terminal of the control module are connected to equipotential end altogether；
The rectification filtering module exports direct current after being filtered rectification to the supply voltage；The control module is by described in
DC inverter is exchange electricity output to the voltage transformation module, and the voltage transformation module carries out voltage to the alternating current
Conversion, and charging voltage is exported to the electrical equipment；The input sample module samples the direct current, and defeated
When entering sampled voltage and being higher than the first predeterminated voltage, the first feedback signal is inputted to the control module, the control module according to
First feedback signal controls the switch module to be closed, so that the voltage transformation module stops output institute
State charging voltage；The first output sampling module samples the alternating current to export the first output sampled voltage, and
When the described first output sampled voltage is higher than the second predeterminated voltage, the second feedback signal is exported to the control module, it is described
Control module controls the switch module to be closed according to second feedback signal, so that the voltage conversion mould
Block stops exporting the charging voltage.
2. power circuit according to claim 1, it is characterised in that the power circuit further includes the second output sampling mould
Block；
The first input end and the second input terminal of the second output sampling module are defeated with the first of the voltage transformation module
Outlet connects, and the output terminal of the second output sampling module is connected with the feedback end of the control module；
The second output sampling module samples the charging voltage to export the second output sampled voltage, and described
When second output sampled voltage is higher than three predeterminated voltages, the 3rd feedback signal, the control mould are exported to the control module
Root tuber controls the switch module to be closed according to the 3rd feedback signal, so that the voltage transformation module stops
Charge to the electrical equipment.
3. power circuit according to claim 1 or 2, it is characterised in that the power circuit further includes protection module；
The input terminal of the protection module receives the supply voltage, the output terminal of the protection module and the rectifying and wave-filtering mould
The input terminal connection of block；
The protection module carries out the supply voltage over-pressed protective treatment, and the supply voltage after processing is exported to described
Rectification filtering module.
4. power circuit according to claim 1 or 2, it is characterised in that the input sample module includes：
First resistor, second resistance, 3rd resistor, the 4th resistance, the first capacitance, the first silicon-controlled and first switching element；
The first end of the first resistor be the input sample module input terminal, the second end of the first resistor with it is described
The first end connection of second resistance, the second end of the second resistance are connected with the first end of the 3rd resistor, and the described 3rd
The second end of resistance and first end, the first end of first capacitance and the first silicon-controlled control of the 4th resistance
End connection processed, the described first silicon-controlled cathode are connected with the control terminal of the first switching element, and described first is silicon-controlled
Anode connects the equipotential end, and the output terminal of the first switching element is the output terminal of the input sample module, and described the
The second end of four resistance and the second end of first capacitance are connected to the equipotential end altogether.
5. power circuit according to claim 1 or 2, it is characterised in that the first output sampling module includes：
First diode, the first storage capacitor, the first zener diode and the 5th resistance；
The anode of first diode for described first output sampling module input terminal, the cathode of first diode with
The cathode of the first end of first storage capacitor and first zener diode connects, and the of first storage capacitor
Two ends are connected to the equipotential end, and the anode of first zener diode is connected with the first end of the 5th resistance, institute
The second end for stating the 5th resistance is the output terminal of the described first output sampling module.
6. power circuit according to claim 1 or 2, it is characterised in that the switch module includes：
Second diode, the 6th resistance, the 7th resistance, the 8th resistance and second switch element；
The first end of 6th resistance connects the control terminal to form the switch module altogether with the first end of the 7th resistance, institute
The second end for stating the 6th resistance is connected with the cathode of second diode, the anode of second diode and the described 7th electricity
The control terminal connection of the second end of resistance, the first end of the 8th resistance and the second switch element, the second switch
The output terminal of element is the output terminal of the switch module, and the input terminal of the second switch element is the defeated of the switch module
Enter end, the second end of the 8th resistance is connected to the equipotential end.
7. power circuit according to claim 2, it is characterised in that the control module includes control chip；
The voltage pin of the control chip is the voltage end of the control module, and the signal input pin of the control chip is
The signal input part of the control module, the controlling switch of the control chip are the signal output part of the control module, institute
The feedback pin for stating control chip is the feedback end of the control module, and the grounding pin of the control chip is the control mould
The ground terminal of block.
8. power circuit according to claim 2, it is characterised in that the second output sampling module includes：
9th resistance, the tenth resistance, the 11st resistance, the 12nd resistance, the 13rd resistance, the 14th resistance, the second capacitance,
Two silicon-controlled and photoelectrical couplers；
The first end of 9th resistance for described second output sampling module first input end, the second of the 9th resistance
End is connected with the first end of the tenth resistance and the first end of the photoelectrical coupler, the second end of the photoelectrical coupler
The first end of second end, second capacitance with the tenth resistance and the second silicon-controlled cathode are connected, described
The second end of second capacitance is connected with the first end of the 11st resistance, the second end and the described tenth of the 11st resistance
The second end of two resistance, the first end of the 14th resistance, the first end of the 13rd resistance and described second controllable
The control terminal connection of silicon, the first end of the 12nd resistance is the described second the second input terminal for exporting sampling module, described
Second silicon-controlled anode is connected to ground, institute altogether with the second end of the 13rd resistance and the second end of the 14th resistance
The 3rd end for stating photoelectrical coupler is the output terminal of the described second output sampling module, the 4th end of the photoelectrical coupler and institute
State the connection of equipotential end.
9. power circuit according to claim 1 or 2, it is characterised in that the power circuit further includes filter module；
The first input end of the filter module is connected with the first output terminal of the voltage transformation module, the filter module
Second input terminal is connected with the second output terminal of the voltage transformation module, the first output terminal of the filter module and second defeated
Outlet is connected with the electrical equipment；
The filter module receives the charging voltage of the voltage transformation module output, and after being filtered to the charging voltage
Charge to the electrical equipment.
10. a kind of set-top box, it is characterised in that the set-top box is included such as claim 1 to 9 any one of them power supply electricity
Road.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721291634.2U CN207265888U (en) | 2017-09-30 | 2017-09-30 | A kind of set-top box and its power circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721291634.2U CN207265888U (en) | 2017-09-30 | 2017-09-30 | A kind of set-top box and its power circuit |
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| CN207265888U true CN207265888U (en) | 2018-04-20 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109546847A (en) * | 2019-01-16 | 2019-03-29 | 合肥惠科金扬科技有限公司 | Synchronization breaking circuit, driving circuit and the synchronous cut-off method of Switching Power Supply |
| CN110602541A (en) * | 2018-06-12 | 2019-12-20 | 瑞昱半导体股份有限公司 | Media streaming device and protection method thereof |
-
2017
- 2017-09-30 CN CN201721291634.2U patent/CN207265888U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110602541A (en) * | 2018-06-12 | 2019-12-20 | 瑞昱半导体股份有限公司 | Media streaming device and protection method thereof |
| CN110602541B (en) * | 2018-06-12 | 2021-08-20 | 瑞昱半导体股份有限公司 | Media streaming device and protection method thereof |
| CN109546847A (en) * | 2019-01-16 | 2019-03-29 | 合肥惠科金扬科技有限公司 | Synchronization breaking circuit, driving circuit and the synchronous cut-off method of Switching Power Supply |
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