CN201203811Y - Power supply circuit and set-top box with the same - Google Patents
Power supply circuit and set-top box with the same Download PDFInfo
- Publication number
- CN201203811Y CN201203811Y CNU2008200236796U CN200820023679U CN201203811Y CN 201203811 Y CN201203811 Y CN 201203811Y CN U2008200236796 U CNU2008200236796 U CN U2008200236796U CN 200820023679 U CN200820023679 U CN 200820023679U CN 201203811 Y CN201203811 Y CN 201203811Y
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- resistance
- circuit
- direct current
- current stabilizer
- output terminal
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Abstract
The utility model discloses a power supply circuit and a set-top box with the power supply circuit, wherein the power supply circuit comprises a DC stabilizer and the input terminal of the DC stabilizer is connected with a DC input power and the output terminal thereof is connected with the output terminal of the power supply circuit by a self-recovery fuse and connected with the input terminal of the power supply circuit by an energy storage inductance on one hand; and the output terminal thereof is connected with the feedback terminal of the DC stabilizer by a first adjustment resistance on the other hand and the feedback terminal is grounded by a second adjustment resistance. The power supply circuit can match the lower DC input system and increase the circuit versatility and with lower power consumption.
Description
Technical field
The utility model relates to a kind of feed circuit, specifically, relates to a kind of feed circuit that can mate low-voltage input power-supply system.
Background technology
The satellite set top box receiving antenna is provided with tuner LNB, includes three end adjustable voltage-regulating ic devices in the circuit for the LNB power supply, and the input end of voltage stabilizer connects direct-current input power supplying, and the output terminal of voltage stabilizer connects the feeder ear of LNB.Owing to need the DC voltage of 13V and 18V during LNB work, to satisfy the switching of its polarization working method, so be provided with adjustment resistance between the adjustment end of three end adjustable voltage-regulating ic devices and the output terminal, regulate the resistance of adjusting resistance by control end, make the output terminal of voltage stabilizer export the DC voltage of 13V and 18V, satisfy the work requirements of LNB.Guarantee that above-mentioned feed circuit can stably export the work DC voltage of needed 18V of LNB, the direct-current input power supplying voltage that the voltage stabilizer input end connects must be greater than 19V.And the direct supply that most of circuit needs in the present set-top-box system is 12V, can not satisfy the power supply requirement of LNB feed circuit.In addition, in above-mentioned feed circuit, because the voltage difference between output end of voltage stabilizer and the output terminal is bigger, be at least 6V, and the working current of LNB is generally more than 0.35A, causes power consumption on the voltage stabilizer more than 2W, the heat that device produces is bigger, is unfavorable for the heat radiation and the steady operation of system.
Summary of the invention
The utility model is at for the circuit of LNB power supply the low direct-current input power supplying system that has relatively high expectations, can not mate of input DC power voltage being caused the relatively poor deficiency of feed circuit versatility in the prior art, a kind of feed circuit are provided, have improved the versatility of feed circuit.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of feed circuit, comprise direct current stabilizer, the input end of described direct current stabilizer connects direct-current input power supplying, and the output terminal of described direct current stabilizer connects the output terminal of feed circuit on the one hand by resettable fuse, and is connected with described input end by an energy storage inductor; Adjust resistance by first on the other hand and be connected with the feedback end of direct current stabilizer, described feedback end is adjusted resistance eutral grounding by second simultaneously.
For preventing the electric current adverse current, between the output terminal of direct current stabilizer and resettable fuse, be in series with diode; The positive pole of described diode is connected with the output terminal of described direct current stabilizer.
Further, the described second adjustment resistance is the resistance of an equivalent circuit, and the control end of described equivalent electrical circuit receives control signal, and changes the resistance of equivalent electrical circuit resistance according to the control signal that receives.Resistance by equivalent electrical circuit is adjusted cooperating of resistance with first, realizes the variable adjustment to stabilizer output voltage, to satisfy the different demands of follow-up load circuit to supply voltage.
Further, comprise a gate-controlled switch circuit in the above-mentioned equivalent electrical circuit, be in series with the 3rd in the switch ways of described on-off circuit and adjust resistance formation series arm, the 4th adjustment resistance and described series arm are formed parallel branch and are connected between the feedback end and ground of direct current stabilizer, the control end of described on-off circuit receives control signal, and according to the turn-on and turn-off of the control signal gauge tap circuit that receives.
As a kind of way of realization of gate-controlled switch circuit, adopt NPN type triode to realize in the described on-off circuit.The collector of described triode is in series with the 3rd and adjusts resistance, the grounded emitter of described triode; The 4th adjusts resistance and the 3rd adjusts the series circuit of resistance and the triode composition formation parallel branch that is in parallel, and is connected between the feedback end and ground of direct current stabilizer; The base stage connection control signal input end of described triode is according to the turn-on and turn-off of the control signal control triode that receives.
For the direct supply with most of circuit is complementary, the voltage of described direct-current input power supplying is preferably 12V.
The utility model discloses a kind of set-top box with above-mentioned feed circuit simultaneously, comprise direct current stabilizer, the input end of described direct current stabilizer connects direct-current input power supplying, the output terminal of described direct current stabilizer connects the output terminal of feed circuit on the one hand by resettable fuse, and is connected with described input end by an energy storage inductor; Adjust resistance by first on the other hand and be connected with the feedback end of direct current stabilizer, described feedback end is adjusted resistance eutral grounding by second simultaneously.
Further, for preventing the electric current adverse current, be in series with diode between the output terminal of described direct current stabilizer and the resettable fuse; The positive pole of described diode is connected with the output terminal of described direct current stabilizer.
Further, the described second adjustment resistance is the resistance of an equivalent circuit, and the control end of described equivalent electrical circuit receives control signal, and changes the resistance of equivalent electrical circuit resistance according to the control signal that receives.By with the cooperating of first resistance, realize variable adjustment, to satisfy the different demands of follow-up load circuit to supply voltage to stabilizer output voltage.
Compared with prior art, advantage of the present utility model and good effect are: by insert the direct supply of low voltage at the direct current stabilizer input end, as the 12V power supply, output terminal at voltage stabilizer can be met multiple supply voltages such as the needed 13V of subsequent conditioning circuit, 18V, can mate the existing used LVPS of most of circuit, improve the versatility of feed circuit.And direct current stabilizer voltage transitions efficient is higher, thereby has reduced the power consumption of entire circuit.
Description of drawings
Fig. 1 is the circuit theory diagrams of an embodiment of the utility model;
Fig. 2 is the circuit theory diagrams of another embodiment of the utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model is described in further detail.
Embodiment one: referring to circuit theory diagrams shown in Figure 1, feed circuit shown in the figure comprise direct current stabilizer U302, and its input terminal P10 connects direct-current input power supplying, and described direct-current input power supplying voltage is 12V.The lead-out terminal P2 of direct current stabilizer U302 is connected with input terminal P10 by energy storage inductor L309 on the one hand, connects the output terminal PWR of feed circuit on the other hand by commutation diode VD301, anti-adverse current diode VD302 and resettable fuse F301.Wherein, the effect of anti-adverse current diode VD302 is the adverse current that prevents when output terminal LNB_PWR voltage electric current during greater than the 12V direct-current input power supplying, and resettable fuse F301 can carry out short-circuit protection to feed circuit.Also be connected with between VD301 and VD302 by the first adjustment resistance R 309 and second and adjust the voltage regulator resistor network that resistance R 308 is formed, the feedback end FB of U302 is connected between R309 and the R308.
The voltage of above-mentioned feed circuit output terminal can calculate by following formula:
Adjust the resistance that resistance R 309 and second is adjusted resistance R 308 by choose reasonable first, can be met its load-carrying voltage requirements at the feed circuit output terminal.
Embodiment two: circuit diagram shown in Figure 2 is the circuit theory diagrams to the power supply of the tuner LNB on the receiving antenna in the set-top box.Feed circuit shown in the figure comprise direct current stabilizer U302, and its input terminal P10 connects direct-current input power supplying.For with the set-top box circuit in the shared power supply of 12V direct supply of other circuit, improved the versatility of feed circuit, the direct-current input power supplying that direct current stabilizer connected also is 12V.The lead-out terminal P2 of direct current stabilizer U302 is connected with input terminal P10 by energy storage inductor L309 on the one hand, connects the output terminal LNB_PWR of feed circuit on the other hand by commutation diode VD301, anti-adverse current diode VD302 and resettable fuse F301.Wherein, the effect of anti-adverse current diode VD302 is the adverse current that prevents when output terminal LNB_PWR voltage electric current during greater than the 12V direct-current input power supplying, and resettable fuse F301 can carry out short-circuit protection to feed circuit.Between VD301 and VD302, also be connected with the first adjustment resistance R 309 and second and adjust the voltage regulator resistor network that resistance is formed.In order to guarantee that feed circuit output terminal LNB_PWR can export LNB when work needed 13V and the DC voltage of 18V, it is the equivalent resistance of an equivalent electrical circuit that second among this embodiment adjusts resistance.Comprise a NPN type triode VT301 in the described equivalent electrical circuit, the collector of described triode is in series with the 3rd and adjusts resistance R 306, the grounded emitter of described triode; The 4th adjusts resistance R 318 is connected in parallel on the upper end formation parallel branch that transistor emitter and the 3rd is adjusted resistance R 306, is connected between the feedback end FB and ground of direct current stabilizer U302.The base stage of triode VT301 controls the turn-on and turn-off of triode by resistance R 304 connection control signal input end VSEL according to the control signal that receives, thereby changes the equivalent resistance of equivalent electrical circuit.
The concrete course of work of foregoing circuit is as follows: when signal input end VSEL is high level, and triode VT301 conducting, the resistance of equivalent electrical circuit is that the 3rd adjustment resistance R 306 and the 4th resistance are adjusted R318 parallel resistor value.In the output end voltage computing formula
In, the R308 of this moment is the parallel resistance of R306 and R318.Reasonably select the resistance of each resistance, for example, R309=330K Ω, R306=100K Ω, R318=41K Ω with the above-mentioned formula of each resistance value substitution, calculate feed circuit output end voltage VLNB_PWR ≈ 18V, thereby LNB is operated in horizontal polarization mode.When signal input end VSEL was low level, triode VT301 ended, and the resistance of equivalent electrical circuit is the 4th and adjusts resistance R 318 resistances.With R308=R318=41K Ω, R309=330K Ω substitution voltage computing formula
In, obtain feed circuit output end voltage V
LNB_PWR≈ 13V, the vertical polarization mode of LNB work.
In addition, because the voltage transitions efficient of direct current stabilizer U302 is higher, be about 90%, the feed circuit electric current is 500mA during by the LNB operate as normal, power consumption in the circuit is 12 * 0.5 * (1-90%)=0.6W, this power consumption is far smaller than the power consumption of feed circuit in the prior art, has reduced the heat of circuit, has improved the mission life of components and parts.
Certainly, need the tuner LNB of 3V/5V polarizing voltage, only need to change the resistance of respectively adjusting resistance and just can realize that 3V/5V voltage switches, and satisfies the polarization job requirement of LNB for some.
The utility model is on the DC power system application basis more and more widely of low voltages such as 12V, consider from aspects such as circuit versatility and power consumptions, propose a kind of new feed circuit, thereby solved the problem that the feed circuit versatility is poor in the prior art, power consumption is big.
Certainly, the above only is a kind of preferred implementation of the present utility model.Should be pointed out that for those skilled in the art under the prerequisite that does not break away from the utility model principle, can also make some improvements and modifications, these improvements and modifications also should be considered as protection domain of the present utility model.
Claims (10)
1, a kind of feed circuit, comprise direct current stabilizer, the input end of described direct current stabilizer connects direct-current input power supplying, it is characterized in that, the output terminal of described direct current stabilizer connects the output terminal of feed circuit on the one hand by resettable fuse, and is connected with described input end by an energy storage inductor; Adjust resistance by first on the other hand and be connected with the feedback end of direct current stabilizer, described feedback end is adjusted resistance eutral grounding by second simultaneously.
2, feed circuit according to claim 1 is characterized in that, are in series with diode between the output terminal of described direct current stabilizer and the resettable fuse; The positive pole of described diode is connected with the output terminal of described direct current stabilizer.
3, feed circuit according to claim 1 and 2 is characterized in that, the described second adjustment resistance is the resistance of an equivalent circuit; The control end of described equivalent electrical circuit receives control signal, and changes the resistance of equivalent electrical circuit resistance according to the control signal that receives.
4, feed circuit according to claim 3, it is characterized in that, comprise a gate-controlled switch circuit in the described equivalent electrical circuit, be in series with the 3rd in the switch ways of described on-off circuit and adjust resistance formation series arm, the 4th adjustment resistance and described series arm are formed parallel branch and are connected between the feedback end and ground of direct current stabilizer, the control end of described on-off circuit receives control signal, and according to the turn-on and turn-off of the control signal gauge tap circuit that receives.
5, feed circuit according to claim 4 is characterized in that, include a NPN type triode in the described on-off circuit, and the collector of described triode is in series with the 3rd and adjusts resistance, the grounded emitter of described triode; The 4th adjusts resistance and the 3rd adjusts the series circuit of resistance and the triode composition formation parallel branch that is in parallel, and is connected between the feedback end and ground of direct current stabilizer; The base stage connection control signal input end of described triode is according to the turn-on and turn-off of the control signal control triode that receives.
6, feed circuit according to claim 1 and 2 is characterized in that, the voltage of described direct-current input power supplying is 12V.
7, feed circuit according to claim 3 is characterized in that, the voltage of described direct-current input power supplying is 12V.
8, a kind of set-top box with the described feed circuit of claim 1, comprise direct current stabilizer, the input end of described direct current stabilizer connects direct-current input power supplying, it is characterized in that, the output terminal of described direct current stabilizer connects the output terminal of feed circuit on the one hand by resettable fuse, and is connected with described input end by an energy storage inductor; Adjust resistance by first on the other hand and be connected with the feedback end of direct current stabilizer, described feedback end is adjusted resistance eutral grounding by second simultaneously.
9, set-top box according to claim 8 is characterized in that, is in series with diode between the output terminal of described direct current stabilizer and the resettable fuse; The positive pole of described diode is connected with the output terminal of described direct current stabilizer.
10, set-top box according to claim 9 is characterized in that, the described second adjustment resistance is the resistance of an equivalent circuit; The control end of described equivalent electrical circuit receives control signal, and changes the resistance of equivalent electrical circuit resistance according to the control signal that receives.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200236796U CN201203811Y (en) | 2008-06-05 | 2008-06-05 | Power supply circuit and set-top box with the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008200236796U CN201203811Y (en) | 2008-06-05 | 2008-06-05 | Power supply circuit and set-top box with the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201203811Y true CN201203811Y (en) | 2009-03-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008200236796U Expired - Lifetime CN201203811Y (en) | 2008-06-05 | 2008-06-05 | Power supply circuit and set-top box with the same |
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| Country | Link |
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| CN (1) | CN201203811Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105826904A (en) * | 2015-01-06 | 2016-08-03 | 鸿富锦精密工业(武汉)有限公司 | Interface power supply circuit |
-
2008
- 2008-06-05 CN CNU2008200236796U patent/CN201203811Y/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105826904A (en) * | 2015-01-06 | 2016-08-03 | 鸿富锦精密工业(武汉)有限公司 | Interface power supply circuit |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20090304 |