CN101806826B - Input voltage detection circuit and power supply circuit - Google Patents
Input voltage detection circuit and power supply circuit Download PDFInfo
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- CN101806826B CN101806826B CN 200910006444 CN200910006444A CN101806826B CN 101806826 B CN101806826 B CN 101806826B CN 200910006444 CN200910006444 CN 200910006444 CN 200910006444 A CN200910006444 A CN 200910006444A CN 101806826 B CN101806826 B CN 101806826B
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Abstract
The invention discloses an input voltage detection circuit and a power supply circuit. The input voltage detection circuit comprises an input circuit, a signal processing circuit, and an output circuit. The input circuit is used for converting the signal intensity and waveform of the input voltage to generate a first signal similar to an input voltage timing sequence; the signal processing circuit is connected with the input circuit and is used for weakening first delay time of the first signal so as to generate a second signal of which the second delay time is shorter than the first delay time; and the output circuit is connected with the signal processing circuit and is used for converting the signal intensity and waveform of a second signal so as to generate a power state signal. When the input voltage is uninterrupted, the power state signal is in an uninterrupted state; and when the input voltage is interrupted, the power state signal is in an interrupted state. The input voltage detection circuit can solve the problem that the input voltage detection circuit has too slow response and too long delay time; and programs before power off are finished in enough time when the input voltage is suddenly interrupted. The power supply circuit also has the function of detecting the input voltage interrupt.
Description
Technical field
The present invention relates to a kind of testing circuit and power supply circuit, relate in particular to a kind of input voltage detection circuit and power supply circuit.
Background technology
In recent years along with the progress of science and technology, electronic product with difference in functionality of all kinds is developed gradually, these electronic products with difference in functionality of all kinds have not only satisfied people's various different demands, more incorporate everyone daily life, so that people's life is more convenient.
The electronic product of these difference in functionalitys of all kinds is comprised of various electronic component, and the required supply voltage of each electronic component is not quite similar, therefore, for the electronic product that makes these difference in functionalitys of all kinds normally moves, need to input voltage be converted to suitable voltage by power-switching circuit, and offer the electronic component use of electronic product.
See also Fig. 1, it is the circuit box schematic diagram of conditional electronic product.As shown in Figure 1, power supply circuit 11 comprises power-switching circuit 111 and input capacitance Cx, and wherein input capacitance Cx is connected in the input end of power-switching circuit 111, in order to electromagnetic interference (EMI) (EMI) characteristic of improving electronic product 1.The output terminal of power-switching circuit 111 is connected in circuit system 12, produces output voltage V o in order to the electric energy that receives input voltage vin and offers circuit system 12.
The electric energy that receives input voltage vin owing to power-switching circuit 111 produces output voltage V o, if when input voltage vin is interrupted suddenly, power-switching circuit 111 also can stop to provide electric energy to give circuit system 12, and causes electronic product 1 out of service abnormally.Yet, the program of some electronic product 1 before front needs out of service are finished some shutdown, such as the game progress storage of game machine, the service data storage of computing machine and the emitting bulb cooling of projector etc., if the program of not finishing before the shutdown just stops electronic product 1 operation, can cause electronic product 1 to start shooting and move or irregular operating.
Just out of service for preventing that electronic product 1 from not finishing the front program of shutdown when input voltage vin is interrupted suddenly, whether correlation technique utilizes input voltage detection circuit to interrupt suddenly to detect input voltage vin, and have no progeny suddenly in detecting input voltage vin, make the program before electronic product 1 is finished shutdown.
See also Fig. 2, it is the signal sequence schematic diagram of traditional input voltage detection circuit.As shown in Figure 2, input voltage vin is interrupted suddenly when very first time t1, because the capacitance of input capacitance Cx and the sending-end impedance of power-switching circuit 111 are larger, so that the time of input capacitance Cx discharge is longer, cause the magnitude of voltage of input voltage vin to descend slowly, moreover because traditional input voltage detection circuit is simple comparator circuit (not shown), can't the rapid reaction input voltage vin interrupt suddenly, and until during the second time t2, the magnitude of voltage of input voltage vin just is lower than reference voltage level, input voltage detection circuit just can detect input voltage vin and interrupted suddenly this moment, and produced the power state signal Vk of the noble potential that represent the input voltage vin interruption.
From the above, the tradition input voltage detection circuit, interrupt having long Td time delay between the power state signal Vk that represents the input voltage vin interruption to exporting in input voltage vin suddenly, therefore, can't be effectively applied to power supply circuit 11, make electronic product 1 can descend and interrupt providing electric energy to make program before circuit system 12 is finished shutdown to the circuit system 12 at output voltage V o at the input voltage vin time enough of having no progeny suddenly.
Therefore, how to develop a kind of input voltage detection circuit and power supply circuit that improves above-mentioned known technology defective, be in fact the present problem in the urgent need to address of those skilled in the technology concerned.
Summary of the invention
The object of the present invention is to provide a kind of input voltage detection circuit, have no progeny suddenly at input voltage, capacitance sending-end impedance large, power-switching circuit the time magnitude of voltage long and input voltage large, the input capacitance discharge that can reduce because of input capacitance descends slowly, and the reaction that causes input voltage detection circuit is crossed slow and time delay long problem, more can be applied to power supply circuit, make electronic product in the input voltage program of time enough before finishing shutdown of having no progeny suddenly.
For reaching above-mentioned purpose, of the present invention one than the broad sense embodiment for a kind of input voltage detection circuit is provided, in order to detecting the state of input voltage, and according to the corresponding power state signal that produces of state of input voltage.This input voltage detection circuit comprises: input circuit, and in order to signal intensity and the waveform of changing input voltage, and generation is similar in appearance to the first signal of input voltage sequential; Signal processing circuit is connected in input circuit, produces the secondary signal of the second time delay less than the first time delay in order to first time delay of subduing first signal; And output circuit, be connected in signal processing circuit, in order to signal intensity and the waveform of changing secondary signal, and produce power state signal.Wherein, power state signal is not an interruption status not when input voltage interrupts, and the power state signal of having no progeny in input voltage is an interruption status.
Another object of the present invention is to provide a kind of power supply circuit, it also has input voltage and interrupts measuring ability, output voltage is provided simultaneously and represents the power state signal whether input voltage interrupts, and have no progeny suddenly in input voltage, utilize power state signal to make electronic product finish the front program of shutdown.Wherein, input voltage is had no progeny suddenly, input voltage detection circuit can not descend slowly by sending-end impedance large because of the capacitance of input capacitance, power-switching circuit time magnitude of voltage long and input voltage large, the input capacitance discharge, and cause the reaction of input voltage detection circuit cross slow and time delay long problem.In addition, power supply circuit of the present invention can use general power-switching circuit, does not need to use the specially designed long power-switching circuit of holding time that has.
For reaching above-mentioned purpose, of the present invention one than the broad sense embodiment for a kind of power supply circuit is provided, in order to output voltage and power state signal to a circuit system to be provided.This power supply circuit comprises: power-switching circuit is connected in circuit system, in order to change input voltage to provide output voltage to circuit system; Input capacitance is connected in the input end of power-switching circuit; And input voltage detection circuit, be connected between the input end and circuit system of power-switching circuit, in order to detecting the state of input voltage, and according to the corresponding power state signal that produces of state of input voltage.This input voltage detection circuit comprises: input circuit, and in order to signal intensity and the waveform of changing input voltage, and generation is similar in appearance to the first signal of input voltage sequential; Signal processing circuit is connected in input circuit, produces the secondary signal of the second time delay less than the first time delay in order to first time delay of subduing first signal; And output circuit, be connected in signal processing circuit and circuit system, in order to signal intensity and the waveform of changing secondary signal, and produce power state signal.Wherein, power state signal is not an interruption status not when input voltage interrupts, and the power state signal of having no progeny in this input voltage is an interruption status.
Input voltage detection circuit of the present invention, have no progeny suddenly in input voltage, the reaction that can reduce input voltage detection circuit cross slow and time delay long problem, more can be applied to power supply circuit of the present invention, make electronic product when input voltage interrupts suddenly, have time enough to finish the front program of shutdown.Power supply circuit of the present invention has more input voltage and interrupts measuring ability, except providing output voltage to the circuit system, more provide and represent power state signal that whether input voltage interrupt to circuit system, and have no progeny suddenly in input voltage, utilize power state signal to make the circuit system of electronic product finish the front program of shutdown.Wherein, input voltage is had no progeny suddenly, input voltage detection circuit can not descend slowly by sending-end impedance large because of the capacitance of input capacitance, power-switching circuit time magnitude of voltage long and input voltage large, the input capacitance discharge, and the reaction that causes input voltage detection circuit is crossed slow and time delay long problem, power supply circuit can use general power-switching circuit, does not need to use the specially designed long power-switching circuit of holding time that has.
Description of drawings
Fig. 1: be the circuit box schematic diagram of conditional electronic product.
Fig. 2: be the signal sequence schematic diagram of traditional input voltage detection circuit.
Fig. 3: be the circuit diagram of the input voltage detection circuit of the preferred embodiment of the present invention.
Fig. 4: be the detailed circuit schematic of Fig. 3.
Fig. 5: be the signal sequence schematic diagram of Fig. 4.
Fig. 6: be another detailed circuit schematic of Fig. 3.
Fig. 7: be the signal sequence schematic diagram of Fig. 6.
Fig. 8: be the circuit box schematic diagram of the power supply circuit of the preferred embodiment of the present invention.
Description of reference numerals in the above-mentioned accompanying drawing is as follows:
1: electronic product 11: power supply circuit
111: power-switching circuit 12: circuit system
3: input voltage detection circuit 31: input circuit
311: reduction voltage circuit 312: the first signal change-over circuit
Comparator circuit 313 in 3121: the first: rectification circuit
32: signal processing circuit 321: control signal produces circuit
33: output circuit 331: filtering circuit
332: 3321: the second comparator circuits of secondary signal change-over circuit
8: electronic product 81: power supply circuit
82: circuit system 812: power-switching circuit
R
1～R
5: the first～the 5th resistance C
1: the first electric capacity
C
2: the second capacitor C
x: input capacitance
D
1: the first diode S
1: the first switch
S
1a: first end S
1b: the second end
K
a: step-down end K
b: the filtering end
COM: meet altogether end V
In: input voltage
V
o: output voltage V
a: step-down voltage
V
b: filtering signal V
C1: control signal
V
r: input rectifying voltage V
Ref1: the first reference voltage
V
Ref2: the second reference voltage V
1: first signal
V
2: secondary signal V
Th: the Continuity signal value
V
k: power state signal T
d: time delay
T
D1～T
D3: first～the 3rd time delay T
In: the cycle
t
1～t
6: the first～the 6th time
Embodiment
Some exemplary embodiments that embody feature ﹠ benefits of the present invention will be described in detail in the explanation of back segment.Be understood that the present invention can have in different modes various variations, its neither departing from the scope of the present invention, and explanation wherein and the accompanying drawing usefulness that ought explain in itself, but not in order to limit the present invention.
See also Fig. 3, it is the circuit diagram of the input voltage detection circuit of the preferred embodiment of the present invention.As shown in Figure 3, input voltage detection circuit 3 of the present invention is in order to detect input voltage V
InWhether interrupt, and according to input voltage V
InState produce power state signal V
kThis input voltage detection circuit 3 comprises: input circuit 31, signal processing circuit 32 and output circuit 33, wherein, the output terminal of input circuit 31 is connected in the input end of signal processing circuit 32, in order to change input voltage V
InSignal intensity and waveform, and produce similar in appearance to input voltage V
InThe first signal V1 of sequential.Signal processing circuit 32 is connected between input circuit 31 and the output circuit 33, in order to subdue first signal V
1First time delay T
D1, and produce secondary signal V
2The input end of output circuit 33 is connected in the output terminal of signal processing circuit 32, in order to change secondary signal V
2Signal intensity and waveform, and produce power state signal V
k
See also Fig. 4, it is the detailed circuit schematic of Fig. 3.As shown in Figure 4, in the present embodiment, input circuit 31 comprises reduction voltage circuit 311 and first signal change-over circuit 312, wherein the step-down end K of reduction voltage circuit 311
aBe connected in the input end of first signal change-over circuit 312, in order to minute compression functions conversion input voltage V by reduction voltage circuit 311
InSignal intensity, and produce the step-down voltage V of signal intensity attenuation
aFirst signal change-over circuit 312 is connected in the input end of signal processing circuit 32 and the step-down end K of reduction voltage circuit 311
aBetween, in order to according to similar in appearance to input voltage V
InThe step-down voltage V of waveform
aGeneration is similar in appearance to input voltage V
InThe first signal V of sequential
1
In the present embodiment, reduction voltage circuit 311 comprises the first resistance R
1With the second resistance R
2, the first resistance R wherein
1With the second resistance R
2An end be connected in the step-down end K of reduction voltage circuit 311
a, and the second resistance R
2The other end be connected in connect altogether the end COM.In the present embodiment, first signal change-over circuit 312 is the first comparator circuit 3121, and wherein the positive input terminal of the first comparator circuit 3121 is connected in the step-down end K of reduction voltage circuit 311
a, and by comparing step-down voltage V
aThe first reference voltage V with the negative input end of the first comparator circuit 3121
Ref1And generation first signal V
1, to realize conversion decompression voltage V
aWaveform and produce first signal V
1
In the present embodiment, signal processing circuit 32 comprises the 3rd resistance R
3, the 4th resistance R
4, the first diode D
1, the first capacitor C
1With the first switch S
1, wherein, the 3rd resistance R
3Be connected between the input end of the output terminal of input circuit 31 and output circuit 33 the first switch S
1First end S
1aBe connected in the 3rd resistance R
3An end, the first switch S
1The second end S
1bBe connected in and meet altogether end COM, and according to the 4th resistance R
4, the first diode D
1With the first capacitor C
1The control signal that consists of produces the control signal V that circuit 321 produces
C1Make the first switch S
1Conducting or cut-off.The first diode D
1Cathode terminal be connected in the 3rd resistance R
3The other end, the first diode D
1Anode tap be connected in the first switch S
1Control end, and the 4th resistance R
4Then be connected in parallel in the first diode D
1The first capacitor C
1Be connected in the first switch S
1Control end connect together the end COM between.In the present embodiment, the first switch S
1Can be but be not defined as bipolar junction transistor (Bipolar Junction Transistor, BJT) or mos field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET).
In the present embodiment, output circuit 33 comprises filtering circuit 331 and secondary signal change-over circuit 332, and wherein the input end of filtering circuit 331 is connected in the output terminal of signal processing circuit 32, the filtering end K of filtering circuit 331
bBe connected in the input end of secondary signal change-over circuit 332, in order to secondary signal V
2Filtering and produce filtering signal V
bThe input end of secondary signal change-over circuit 332 is connected in the filtering end K of filtering circuit 331
b, in order to according to similar in appearance to secondary signal V
2The filtering signal V of sequential
bProduce power state signal V
k
In the present embodiment, filtering circuit 331 comprises the 5th resistance R 5 and the second capacitor C
2, the 5th resistance R wherein
5An end be connected in filtering end K
bWith the input end of secondary signal change-over circuit 332, the 5th resistance R
5The other end be connected in the output terminal of signal processing circuit 32, and the second capacitor C
2Then be connected in filtering end K
bConnect together between the end COM.In the present embodiment, secondary signal change-over circuit 332 is the second comparator circuit 3321, and wherein the negative input end of the second comparator circuit 3321 is connected in the filtering end K of filtering circuit 331
b, and by comparing filtering signal V
bThe second reference voltage V with the positive input terminal of the second comparator circuit 3321
Ref2And generation power state signal V
k
See also Fig. 5 and cooperate Fig. 4, wherein Fig. 5 is the signal sequence schematic diagram of Fig. 4.As shown in Figure 5, in the 3rd time t
3Before, input voltage V
InStep-down voltage V with signal intensity attenuation
aBe all the string ripple, and input voltage V
InWith step-down voltage V
aCycle T
InIdentical.In the 3rd time t
3The time, input voltage V
InInterrupt input voltage V suddenly
InStep-down voltage V with signal intensity attenuation
aThe magnitude of voltage slow decreasing.First signal V
1Basis signal strength retrogression's step-down voltage V
aProduce, as step-down voltage V
aGreater than the first reference voltage V
Ref1The time, the first comparator circuit 3121 can produce the first signal V of noble potential
1, on the contrary, as step-down voltage V
aLess than the first reference voltage V
Ref1The time, the first comparator circuit 3121 can produce the first signal V of electronegative potential
1Therefore, input circuit 31 passes through the first comparator circuit 3121 with step-down voltage V
aWaveform transformation be the first signal V of square wave
1, and first signal V
1Sequential is similar in appearance to input voltage V
In
Control signal produces circuit 321 and utilizes first signal V
1Make the first capacitor C
1Charge and discharge and produce control signal V
C1, as first signal V
1During for noble potential, first signal V
1Electric energy via the 4th resistance R
4To the first capacitor C
1Charging is as first signal V
1During for electronegative potential, the first capacitor C
1Electric energy via the first diode D
1Discharge.Because the first capacitor C
1Charge path can be through the 4th resistance R
4, and discharge path only passes through the first less diode D of resistance characteristic
1, so that the first capacitor C
1Charging is slowly discharged faster, and in input voltage V
InCycle T
InHalf the time length in, control signal V
C1Can't rise and surpass the first switch S
1Continuity signal value V
ThTherefore, control signal V
C1At input voltage V
InThe 3rd time t that interrupts
3In the past, control signal V
C1Do not reach Continuity signal value V
ThSo, the first switch S
1Cut-off.
Yet, input voltage V
InThe 3rd time t that interrupts
3Afterwards, because input voltage V
InThe magnitude of voltage slow decreasing so that first signal V
1For the time span of noble potential greater than input voltage V
InCycle T
InHalf, and then make the first capacitor C
1The time enough charging is arranged, and in input voltage V
InIn the 4th time t that has no progeny
4, control signal V
C1Arrive the first switch S
1Continuity signal value V
Th, make the first switch S
1Conducting.
It is the 3rd resistance R between the input end of signal processing circuit 32 and the output terminal
3, when the first switch S
1During cut-off, secondary signal V
2Similar in appearance to first signal V
1, both waveforms and sequential are identical, when the first switch S
1During conducting, secondary signal V
2For connecing altogether the electronegative potential of end COM.Because the 4th time t
4Before, the first switch S
1So cut-off is secondary signal V
2Similar in appearance to first signal V
1, both waveforms and sequential are identical, the 4th time t
4Afterwards, the first switch S
1Conducting, so secondary signal V
2For connecing altogether the electronegative potential of end COM.
Although input voltage V
InIn have no progeny input voltage V
InWith step-down voltage V
aThe magnitude of voltage slow decreasing, in the 6th time t
6The time, step-down voltage V
aMagnitude of voltage just be lower than the first reference voltage V
Ref1, cause first signal V
1Have the time long first time delay T
D1But signal processing circuit 32 is utilized the first switch S
1In the 4th time t
4The time conducting, subdue first signal V
1First time delay T
D1, and produce second time delay T
D2Less than first time delay T
D1Secondary signal V
2
In addition, secondary signal V
2Via the 5th resistance R
5With the second capacitor C
2The low-pass filter circuit filtering secondary signal V that consists of
2Radio-frequency component and produce filtering signal V
bSo, filtering signal V
bThe sequential of rise and fall can be similar in appearance to secondary signal V
2, therefore, the second comparator circuit 3321 is according to filtering signal V
bThe power state signal V that produces
kAlso have less than first time delay T
D1The 3rd time delay T
D3Wherein, in the 5th time t
5Before, filtering signal V
bGreater than the second reference voltage V
Ref2, 3321 outputs of the second comparator circuit represent input voltage V
InThe power state signal V that does not interrupt
kIn the 5th time t
5Afterwards, filtering signal V
bLess than the second reference voltage V
Ref2, 3321 outputs of the second comparator circuit represent input voltage V
InThe power state signal V that interrupts
k
In the present embodiment, power state signal V
kHave interruption status and interruption status not, and represent with noble potential and electronegative potential respectively, in certain embodiments, the annexation of the second comparator circuit (not shown) positive input terminal that is different from the second comparator circuit 3321, the second comparator circuits of Fig. 4 is connected in the filtering end K of filtering circuit 331
b(not shown), and by comparing filtering signal V
bThe second reference voltage V with the negative input end of the second comparator circuit
Ref2And generation power state signal V
kSo, power state signal V
kInterruption status represent with electronegative potential and noble potential respectively with interruption status not.
See also Fig. 6 and cooperate Fig. 4, wherein Fig. 6 is another detailed circuit schematic of Fig. 3.Input voltage detection circuit 3 differences of Fig. 6 and Fig. 4 are that the input circuit 31 of Fig. 6 except comprising reduction voltage circuit 311 and first signal change-over circuit 312, also comprises input end and input voltage V that rectification circuit 313 is connected in reduction voltage circuit 311
InBetween, in order to input voltage V
InRectification and produce input rectifying voltage V
rChange input rectifying voltage V by minute compression functions of reduction voltage circuit 311 again
rSignal intensity, and produce the step-down voltage V of signal intensity attenuation
aWherein, rectification circuit 313 can be full-wave rectification pattern or half-wave rectification pattern, and in the present embodiment, rectification circuit 313 is the bridge rectifier circuit of full-wave rectification pattern, but not as limit.As for, the annexation of other circuit and electronic component and operation logic are not given unnecessary details at this similar in appearance to Fig. 4 among Fig. 6.
See also Fig. 7 and cooperate Fig. 4, Fig. 5 and Fig. 6, wherein Fig. 7 is the signal sequence schematic diagram of Fig. 6.Fig. 7 is similar to Fig. 5, and the main difference part is step-down voltage V
a, because the input circuit 31 of Fig. 6 is not just with input voltage V
InSignal intensity attenuation, but with input voltage V
InRectification is deamplification intensity and produce step-down voltage V simultaneously
a, therefore, the step-down voltage V of Fig. 7
aBe input voltage V
InThe waveform of rectification and deamplification intensity.As for, the first signal V of square wave shown in Figure 7
1Equally be according to step-down voltage V
aProduce, and first signal V
1Sequential is the same as input voltage V
InAnd first signal V
1, control signal V
C1, secondary signal V
2, filtering signal V
bWith power state signal V
kBetween relation also identical, do not given unnecessary details at this.
From the above, input voltage V
In, step-down voltage V
aWith first signal V
1First time delay T
D1Not only greater than input voltage V
InCycle T
InSeveral times, first time delay T
D1Especially greater than input voltage V
InCycle T
InSeveral times.Input voltage detection circuit 3 of the present invention utilizes signal processing circuit 32, can with first time delay T
D1Subdue to an input voltage V
InCycle T
In, so that first time delay T
D1With second time delay T
D2Between mistiming, and first time delay T
D1With the 3rd time delay T
D3Between mistiming at least greater than an input voltage V
InCycle T
In, and in certain embodiments, first time delay T
D1With the 3rd time delay T
D3Can be less than an input voltage V
InCycle T
In
See also Fig. 8, it is the circuit box schematic diagram of the power supply circuit of the preferred embodiment of the present invention.As shown in Figure 8, electronic product 8 comprises power supply circuit 81 and circuit system 82, and wherein, power supply circuit 81 of the present invention is except providing output voltage V
oTo circuit system 82, more provide power state signal V
kGive circuit system 82, make the circuit system 82 can be according to power state signal V
kState finish the shutdown before program.
Input voltage V
InSuddenly have no progeny in, because power supply circuit 81 has output capacitance (not shown), power supply circuit 81 provides to the output voltage V of circuit system 82
oCan not be subjected at once input voltage V
InSuddenly interrupt affecting inscribing for thirty years of age and fall, output voltage V o still can be maintained load voltage value, until input voltage V
InHave no progeny in again through holding time (hold time) output voltage V suddenly
oJust can descend and interrupt providing electric energy to circuit system 82.
Similarly, input capacitance C
xCapacitance and the sending-end impedance of power-switching circuit larger so that input capacitance C
xIn input voltage V
InSuddenly have no progeny in time of discharge is longer, causes input voltage V
InMagnitude of voltage descend slowly.Because input voltage detection circuit 3 of the present invention can be subdued input voltage V
InFirst time delay T
D1Even, in input voltage V
InInterrupt and input voltage V suddenly
InMagnitude of voltage descend slowly, input voltage detection circuit 3 still can produce more quickly and represent input voltage V
InThe power state signal V that interrupts
k, make circuit system 82 have the time enough can be in output voltage V
oDecline and interruption provide electric energy to finish the front program of shutdown to circuit system 82.
In other words, input voltage detection circuit 3 has the more quickly reaction time, so, power supply circuit 81 of the present invention can use the power-switching circuit 812 of any type to realize, for example boost type (Boost), buck (Buck) or step-down/up type (Buck-boost), do not need to use the specially designed long power-switching circuit of holding time that has, the output capacitance (not shown) of large capacitance for example is set in the output terminal of power-switching circuit, and in input voltage V
InHave no progeny the output voltage V that power-switching circuit produces in suddenly
oHold time and enough make circuit system 82 in output voltage V
oDecline and interruption provide electric energy to make circuit system 82 finish the front program of shutdown to circuit system 82.
The required electric energy of the partial circuit of input voltage detection circuit 3 of the present invention and electronic component provides (not shown) by power-switching circuit 812, therefore, and in input voltage V
InHave no progeny in, in output voltage V suddenly
oThe interior input voltage detection circuit 3 of holding time still can normally move, and input voltage detection circuit 3 can be in response to the input voltage V that interrupts
InThe corresponding generation represents input voltage V
InThe power state signal V that interrupts
k
Please consult again Fig. 6 and cooperate Fig. 8, in certain embodiments, the rectification circuit 313 of input voltage detection circuit 3 more can share (not shown) with power-switching circuit 812 among Fig. 6, can use equally voltage detecting circuit 3 and power-switching circuit 812 normally to move, to reduce cost, circuit complexity and the volume of power supply circuit 81.
In sum, input voltage detection circuit of the present invention, have no progeny suddenly in input voltage, can reduce because the capacitance of input capacitance is large, the sending-end impedance of power-switching circuit is large, the time input capacitance discharge magnitude of voltage long and input voltage descends slowly, and the reaction that causes input voltage detection circuit is crossed slow and time delay long problem, more can be applied to power supply circuit of the present invention, make electronic product when input voltage interrupts suddenly, have time enough to finish the front program of shutdown.
In addition, power supply circuit of the present invention has more input voltage and interrupts measuring ability, except providing output voltage to the circuit system, more provide and represent power state signal that whether input voltage interrupt to circuit system, and have no progeny suddenly in input voltage, utilize power state signal to make the circuit system of electronic product finish the front program of shutdown.Wherein, input voltage is had no progeny suddenly, input voltage detection circuit can not descend slowly by sending-end impedance large because of the capacitance of input capacitance, power-switching circuit time magnitude of voltage long and input voltage large, the input capacitance discharge, and the reaction that causes input voltage detection circuit is crossed slow and time delay long problem, power supply circuit can use general power-switching circuit, does not need to use the specially designed long power-switching circuit of holding time that has.
The present invention must be appointed by those of ordinary skill in the art and executes that the craftsman thinks and be to modify right neither scope of taking off the wish protection of claims institute as all.
Claims (20)
1. input voltage detection circuit, in order to detecting the state of an input voltage, and according to the corresponding power state signal that produces of state of this input voltage, this input voltage detection circuit comprises:
One input circuit, in order to signal intensity and the waveform of changing this input voltage, and generation is similar in appearance to a first signal of this input voltage sequential;
One signal processing circuit is connected in this input circuit, produces the secondary signal of one second time delay less than this first time delay in order to one first time delay of subduing this first signal; And
One output circuit is connected in this signal processing circuit, in order to signal intensity and the waveform of changing this secondary signal, and produces a power state signal;
Wherein, this power state signal is not an interruption status not when this input voltage interrupts, and this power state signal of having no progeny in this input voltage is an interruption status.
2. input voltage detection circuit as claimed in claim 1, wherein one the 3rd time delay of this power state signal is less than this first time delay of this first signal.
3. input voltage detection circuit as claimed in claim 1, wherein this input circuit comprises:
One reduction voltage circuit produces a step-down voltage of signal intensity attenuation in order to switching signal intensity; And
One first signal change-over circuit is connected between this signal processing circuit and this reduction voltage circuit, in order to produce this first signal similar in appearance to this input voltage sequential according to this step-down voltage.
4. input voltage detection circuit as claimed in claim 3, wherein this input circuit more comprises a rectification circuit, is connected between this input voltage and this reduction voltage circuit, in order to rectification, makes this step-down voltage be the waveform of this input voltage rectification and signal intensity attenuation.
5. input voltage detection circuit as claimed in claim 3, wherein this reduction voltage circuit comprises:
One first resistance, an end of this first resistance are connected in a step-down end of this reduction voltage circuit; And
One second resistance is connected in this end of this first resistance and this step-down end of this reduction voltage circuit.
6. input voltage detection circuit as claimed in claim 3, wherein this first signal change-over circuit is one first comparator circuit, this first comparator circuit is this step-down voltage and one first reference voltage and produce this first signal relatively, with the waveform of realizing this step-down voltage of conversion and produce this first signal.
7. input voltage detection circuit as claimed in claim 1, wherein this signal processing circuit comprises:
One the 3rd resistance is connected between this input circuit and this output circuit;
One first switch is connected in an end of the 3rd resistance; And
One control signal produces circuit, is connected between the other end of the control end of this first switch and the 3rd resistance, produce a control signal in order to utilize this first signal, and this first switch is according to this control signal conducting or cut-off;
Wherein, this control signal does not reach a Continuity signal value of this first switch when this input voltage does not interrupt, this control signal after this input voltage interrupts through reaching this Continuity signal value of this first switch this second time delay.
8. input voltage detection circuit as claimed in claim 7, wherein this control signal produces circuit and comprises:
One first diode is connected between the control end of the other end of the 3rd resistance and this first switch;
One the 4th resistance is connected in parallel in this first diode; And
One first electric capacity is connected in the control end of this first switch;
Wherein, this control signal is utilized this first signal to make this first capacitor charging and discharge and is produced.
9. input voltage detection circuit as claimed in claim 1, wherein this output circuit comprises:
One filtering circuit is connected in this signal processing circuit, in order to this secondary signal filtering is produced a filtering signal; And
One secondary signal change-over circuit is connected in this filtering circuit, in order to produce this power state signal according to this filtering signal.
10. input voltage detection circuit as claimed in claim 9, wherein this filtering circuit is low-pass filter circuit.
11. a power supply circuit, in order to an output voltage and power state signal to a circuit system to be provided, this power supply circuit comprises:
One power-switching circuit is connected in this circuit system, in order to change an input voltage to provide this output voltage to this circuit system;
One input capacitance is connected in the input end of this power-switching circuit; And
One input voltage detection circuit is connected between the input end and this circuit system of this power-switching circuit, and in order to detecting the state of this input voltage, and according to corresponding this power state signal that produces of state of this input voltage, this input voltage detection circuit comprises:
One input circuit, in order to signal intensity and the waveform of changing this input voltage, and generation is similar in appearance to a first signal of this input voltage sequential;
One signal processing circuit is connected in this input circuit, produces the secondary signal of one second time delay less than this first time delay in order to one first time delay of subduing this first signal; And
One output circuit is connected in this signal processing circuit and this circuit system, in order to signal intensity and the waveform of changing this secondary signal, and produces this power state signal;
Wherein, this power state signal is not an interruption status not when this input voltage interrupts, and this power state signal of having no progeny in this input voltage is an interruption status.
12. power supply circuit as claimed in claim 11, wherein one the 3rd time delay of this power state signal is less than this first time delay of this first signal.
13. power supply circuit as claimed in claim 11, wherein this input circuit comprises:
One reduction voltage circuit produces a step-down voltage of signal intensity attenuation in order to switching signal intensity; And
One first signal change-over circuit is connected between this signal processing circuit and this reduction voltage circuit, in order to produce this first signal similar in appearance to this input voltage sequential according to this step-down voltage.
14. power supply circuit as claimed in claim 13, wherein this input circuit also comprises a rectification circuit, is connected between this input voltage and this reduction voltage circuit, in order to rectification, makes this step-down voltage be the waveform of this input voltage rectification and signal intensity attenuation.
15. power supply circuit as claimed in claim 13, wherein this reduction voltage circuit comprises:
One first resistance, an end of this first resistance are connected in a step-down end of this reduction voltage circuit; And
One second resistance is connected in this end of this first resistance and this step-down end of this reduction voltage circuit.
16. power supply circuit as claimed in claim 13, wherein this first signal change-over circuit is one first comparator circuit, this first comparator circuit is this step-down voltage and one first reference voltage and produce this first signal relatively, with the waveform of realizing this step-down voltage of conversion and produce this first signal.
17. power supply circuit as claimed in claim 11, wherein this signal processing circuit comprises:
One the 3rd resistance is connected between this input circuit and this output circuit;
One first switch is connected in an end of the 3rd resistance; And
One control signal produces circuit, is connected between the other end of the control end of this first switch and the 3rd resistance, produce a control signal in order to utilize this first signal, and this first switch is according to this control signal conducting or cut-off;
Wherein, this control signal does not reach a Continuity signal value of this first switch when this input voltage does not interrupt, this control signal after this input voltage interrupts through reaching this Continuity signal value of this first switch this second time delay.
18. power supply circuit as claimed in claim 17, wherein this control signal generation circuit comprises:
One first diode is connected between the control end of the other end of the 3rd resistance and this first switch;
One the 4th resistance is connected in parallel in this first diode; And
One first electric capacity is connected in the control end of this first switch;
Wherein, this control signal is utilized this first signal to make this first capacitor charging and discharge and is produced.
19. power supply circuit as claimed in claim 11, wherein this output circuit comprises:
One filtering circuit is connected in this signal processing circuit, in order to this secondary signal filtering is produced a filtering signal; And
One secondary signal change-over circuit is connected in this filtering circuit, in order to produce this power state signal according to this filtering signal.
20. power supply circuit as claimed in claim 19, wherein this filtering circuit is low-pass filter circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910006444 CN101806826B (en) | 2009-02-18 | 2009-02-18 | Input voltage detection circuit and power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910006444 CN101806826B (en) | 2009-02-18 | 2009-02-18 | Input voltage detection circuit and power supply circuit |
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| Publication Number | Publication Date |
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| CN101806826A CN101806826A (en) | 2010-08-18 |
| CN101806826B true CN101806826B (en) | 2013-04-17 |
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| CN 200910006444 Active CN101806826B (en) | 2009-02-18 | 2009-02-18 | Input voltage detection circuit and power supply circuit |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105652074B (en) * | 2014-12-03 | 2018-08-10 | 万国半导体(开曼)股份有限公司 | Voltage detecting circuit and the method for detecting voltage change |
| TWI635725B (en) * | 2016-10-07 | 2018-09-11 | 普萊德科技股份有限公司 | Network switching system |
| CN109541285B (en) * | 2018-12-26 | 2020-12-08 | 东莞市长工微电子有限公司 | Buckboost circuit output current detection method and detection circuit thereof |
| CN113109618A (en) * | 2021-03-22 | 2021-07-13 | 成都芯源系统有限公司 | Rapid input voltage signal detection circuit and method thereof |
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| CN101806826A (en) | 2010-08-18 |
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