CN202939206U - Voltage detection circuit - Google Patents
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- CN202939206U CN202939206U CN 201220658886 CN201220658886U CN202939206U CN 202939206 U CN202939206 U CN 202939206U CN 201220658886 CN201220658886 CN 201220658886 CN 201220658886 U CN201220658886 U CN 201220658886U CN 202939206 U CN202939206 U CN 202939206U
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Abstract
The utility model provides a voltage detection circuit, voltage detection circuit can be used to detect switching power supply circuit's output voltage, switching power supply circuit includes energy storage element, the first power switch and the second power switch that are coupled with energy storage element, and wherein, when first power switch switches on, energy storage element stored energy, when first power switch closes, energy storage element is to load output energy, include: the sampling and holding circuit is provided with an input end and an output end, the input end is coupled to a connection point of the energy storage element and the first power switch, when the first power switch is turned off, the sampling and holding circuit samples the voltage of the connection point of the energy storage element and the first power switch, and the output end outputs a sampling signal; and an averaging circuit having an input terminal coupled to the output terminal of the sample-and-hold circuit to receive the sampled signal and an output terminal outputting a detection voltage proportional to the output voltage of the switching power supply circuit.
Description
Technical field
Present technique relates to a kind of electronic control system, is specifically related to a kind of light emitting diode (LED) driving circuit and method thereof.
Background technology
Switching power circuit receives supply voltage, the electronic equipment that provides the output voltage after conversion to power to needs.In order to meet the requirement of rear class electronic equipment to voltage, the output voltage of switching power circuit need to limit within the specific limits usually.Therefore, in switching power circuit, need to use voltage detecting circuit and detect output voltage, in order to take corresponding measure when output voltage is too high or too low.Simultaneously, voltage detecting circuit also can be applied in other occasions.Fig. 1 shows the electrical block diagram of existing inverse-excitation type switch power-supply circuit.In this circuit, need to adopt optocoupler D0 to detect output voltage V o, and output voltage V o is fed back to the feedback pin FB of control chip 101 by tertiary winding Lt.Adopt the method to detect output voltage V o, not only need to use the electron devices such as optocoupler D0, tertiary winding Lt, and circuit structure is very complicated.
The utility model content
Consider one or more technical matterss of prior art, proposed a kind of voltage detecting circuit.
Embodiment according to present technique, a kind of voltage detecting circuit has been proposed, described voltage detecting circuit can be used for the output voltage of detector switch power circuit, described switching power circuit comprises energy-storage travelling wave tube and the first power switch and the second power switch that couple with energy-storage travelling wave tube, wherein, energy-storage travelling wave tube is storage power when the first power switch conducting, when turn-offing, the first power switch exports energy to load, comprise: sampling hold circuit, there is input end and output terminal, described input end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, described output terminal output sampled signal, and averaging circuit, thering is input end and output terminal, the output terminal that described input end is coupled to sampling hold circuit receives sampled signal, the detection signal that described output terminal output is directly proportional to the output voltage of switching power circuit.
In one embodiment, described sampling hold circuit comprises: sampling switch, there is first end, the second end and control end, described first end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, described control end receives sampling control signal, and described sampling control signal is controlled the sampling switch closure when the first power switch shutoff and the second power switch conducting; And sampling capacitance, thering is first end and the second end, described first end is coupled to the second end of sampling switch, described the second end ground connection.
In one embodiment, described sampling hold circuit also comprises driver, and described driver is coupled between the output terminal of the first end of sampling capacitance and sampling hold circuit.
In one embodiment, described voltage detecting circuit also comprises bleeder circuit, described bleeder circuit has input end and output terminal, described input end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, the voltage division signal that described output terminal output is directly proportional to the voltage of the tie point of energy-storage travelling wave tube and the first power switch.
In one embodiment, described sampling hold circuit comprises: sampling switch, there is first end, the second end and control end, described first end is coupled to the output terminal of bleeder circuit, described control end receives sampling control signal, and described sampling control signal is controlled the sampling switch closure when the first power switch shutoff and the second power switch conducting; And sampling capacitance, thering is first end and the second end, described first end is coupled to the second end of sampling switch, and described the second end ground connection, produce sampled signal on described first end.
In one embodiment, described sampling hold circuit also comprises driver, and described driver is coupled between the output terminal of the first end of sampling capacitance and sampling hold circuit.
In one embodiment, described averaging circuit comprises: the first switch, there is first end, the second end and control end, described first end is coupled to the output terminal of sampling hold circuit, described control end receives the first control signal, described the first switch is closure when the first power switch conducting, when the first power switch turn-offs, disconnects; Second switch, have first end, the second end and control end, and described first end is coupled to the second end of the first switch, described the second end ground connection, described control end receives the second control signal, and described second switch disconnects when the first power switch conducting, closure when the first power switch turn-offs; Low-pass filter circuit, have input end and output terminal, and described input end is coupled to coupling a little of the first switch and second switch, described output terminal output detection signal.
In one embodiment, described low-pass filter circuit comprises: resistance, there is first end and the second end, and described first end is coupled to the tie point of the first switch and second switch, and described the second end is coupled to the output terminal of averaging circuit; And average capacitance, thering is first end and the second end, described first end is coupled to the second end of resistance, described the second end ground connection; Wherein, coupling of described resistance and average capacitance produces a detection signal.
According to the voltage detecting circuit of the above-mentioned each side of the utility model, circuit structure is simple, without electron devices such as optocoupler, the tertiary windings, has reduced circuit cost.
The accompanying drawing explanation
In order better to understand the utility model, will to the utility model, be described in detail according to the following drawings:
Fig. 1 shows the electrical block diagram of existing inverse-excitation type switch power-supply circuit;
Fig. 2 shows the structural representation according to the voltage detecting circuit 20 of the utility model one embodiment;
The waveform schematic diagram of each signal when Fig. 3 shows inverse-excitation type switch power-supply circuit in Fig. 2 and is operated in the cutout pattern;
Fig. 4 shows the structural representation according to the buck switching power circuit of the employing voltage detecting circuit 20 of the utility model one embodiment;
The waveform schematic diagram of each signal when Fig. 5 shows buck switching power circuit in Fig. 4 and is operated in the cutout pattern.
Embodiment
Below will describe specific embodiment of the utility model in detail, it should be noted that the embodiments described herein, only for illustrating, is not limited to the utility model.In the following description, in order to provide thorough understanding of the present utility model, a large amount of specific detail have been set forth.Yet, for those of ordinary skills, it is evident that: needn't adopt these specific detail to carry out the utility model.In other examples, for fear of obscuring the utility model, do not specifically describe known circuit, material or method.
In whole instructions, " embodiment ", " embodiment ", " example " or mentioning of " example " are meaned: special characteristic, structure or characteristic in conjunction with this embodiment or example description are comprised at least one embodiment of the utility model.Therefore, phrase " in one embodiment ", " in an embodiment ", " example " or " example " occurred in each place of whole instructions differs to establish a capital and refers to same embodiment or example.In addition, can with any suitable combination and/or sub-portfolio by specific feature, structure or property combination in one or more embodiment or example.In addition, it should be understood by one skilled in the art that the accompanying drawing provided at this is all for illustrative purposes, and accompanying drawing is not necessarily drawn in proportion.Should be appreciated that when claiming element " to be connected to " or during " being couple to " another element, it can be directly connected or coupled to another element or can have intermediary element.On the contrary, when claiming element " to be directly connected to " or during " being directly coupled to " another element, not having intermediary element.Identical Reference numeral is indicated identical element.Term used herein " and/or " comprise any and all combinations of one or more relevant projects of listing.
Fig. 2 shows the structural representation according to the voltage detecting circuit 20 of the utility model one embodiment.In Fig. 2, voltage detecting circuit 20 is applied in inverse-excitation type switch power-supply circuit.Described inverse-excitation type switch power-supply circuit comprises energy-storage travelling wave tube T1, and the first power switch MP and the second power switch Ds that couple with energy-storage travelling wave tube T1, and output capacitance Co produce output voltage V o on output capacitance Co, drive pull-up resistor RL.Described energy-storage travelling wave tube T1 comprises transformer, and described transformer comprises former limit winding L p and the secondary winding L s that turn ratio is Np: Ns.Described former limit winding L p receives input voltage vin.Described the second power switch Ds comprises power diode.When the first power switch MP conducting, described former limit winding L p storage power, described output capacitance Co provides energy to pull-up resistor RL; When the first power switch MP turn-offs, described former limit winding L p transfers the energy to secondary winding L s, and described secondary winding L s charges to output capacitance Co and provides energy to pull-up resistor RL.The control signal G1 of described the first power switch MP can be provided by the control circuit of known inverse-excitation type switch power-supply circuit.
In Fig. 2, described voltage detecting circuit 20 comprises: bleeder circuit 203, described bleeder circuit 203 has input end and output terminal, described input end is coupled to the tie point of energy-storage travelling wave tube T1 and the first power switch MP, the voltage division signal VF that described output terminal output is directly proportional to the voltage VA of the tie point of energy-storage travelling wave tube T1 and the first power switch MP; Sampling hold circuit 201, there is input end and output terminal, the output terminal that described input end is coupled to bleeder circuit 203 receives voltage division signal VF, when the first power switch MP shutoff and the second power switch Ds conducting, described sampling hold circuit 201 sampling voltage division signal VF, described output terminal output sampled signal VB; And averaging circuit 202, thering is input end and output terminal, the output terminal that described input end is coupled to sampling hold circuit 201 receives sampled signal VB, the detection signal VD that described output terminal output is directly proportional to output voltage V o.
In one embodiment, bleeder circuit 203 comprises divider resistance R1 and R2.The common practise that the principle of work of bleeder circuit 203 is this area, no longer elaborate.Those of ordinary skills should be understood that and anyly can carry out dividing potential drop to voltage VA, obtain voltage division signal VF and all can be used as bleeder circuit with the circuit that meets the requirement of late-class circuit input voltage range.Simultaneously, if the value of voltage VA can meet the input voltage range requirement of late-class circuit, be that the value of voltage VA is in the input range of sampling hold circuit 201, bleeder circuit 203 can omit, the input end of described sampling hold circuit 201 is coupled to the tie point of energy-storage travelling wave tube T1 and the first power switch MP, sampled voltage VA.
In one embodiment, described sampling hold circuit 201 comprises: sampling switch Ms, there is first end, the second end and control end, described first end is coupled to the output terminal of sampling hold circuit 201, described control end receives sampling control signal G2, and described sampling control signal G2 (when energy-storage travelling wave tube T1 exports energy to load) when the first power switch MP shutoff and the second power switch Ds conducting controls sampling switch Ms closure; And sampling capacitance C1, thering is first end and the second end, described first end is coupled to the second end of sampling switch Ms, described the second end ground connection.
In one embodiment, sampling control signal G2 has characterized the break-make of the second power switch Ds, when the second power switch Ds turn-offs, sampling control signal G2 is in the first signal state, low level for example, when the second power switch Ds conducting, sampling control signal G2 for example, in secondary signal state, high level.
In one embodiment, when sampling control signal G2 is high level, sampling switch Ms closure; When sampling control signal G2 is low level, sampling switch Ms disconnects.
The voltage VA of the tie point that in one embodiment, sampling control signal G2 can be by detecting energy-storage travelling wave tube T1 and the first power switch MP obtains.When the first power switch MP conducting, the value of voltage VA is close to 0; At the first power switch MP, turn-off, during the second power switch Ds conducting,
When the first power switch MP and the second power switch Ds turn-off simultaneously, the decay of the value starting oscillation of voltage VA.As can be seen here, only, when the second power switch Ds conducting, the value of voltage VA is maximum.Therefore, as long as a comparator circuit is set, by the value of voltage VA with
Compare, can obtain sampling control signal G2.In actual applications, due to the moment of all turn-offing at the first power switch MP and the second power switch Ds, the value of voltage VA can drop to the value that approaches 0 within first oscillation period, therefore the value of voltage VA and one can be greater than to 0, is less than
Value compare.The selection of concrete numerical value can decide according to the requirement of practical situations and precision.
In one embodiment, can be by detecting the break-make of the first power switch MP, and the zero crossing that flows through the electric current I s of the second winding L s obtains sampling control signal G2.For example, when the first power switch MP turn-offs, sampling control signal G2 is effective status from the disarmed state saltus step, and when electric current I s zero passage, sampling control signal G2 is disarmed state from the effective status saltus step.
In one embodiment, described sampling hold circuit 201 also comprises driver 2011, and described driver 2011 is coupled between the output terminal of the first end of sampling capacitance C1 and sampling hold circuit 201.Those of ordinary skills should be understood that the purpose that adds driver 2011 is in order to prevent that electric charge on sampling capacitance C1 from leaking to the output terminal of sampling hold circuit 201.
Those of ordinary skills will be appreciated that; any can be when sampling control signal be effective; during i.e. the second power switch Ds conducting; voltage VA to the tie point of energy-storage travelling wave tube T1 and the first power switch MP is sampled; in other period, the circuit of the magnitude of voltage that maintenance samples is all in the utility model protection domain.
In one embodiment, averaging circuit 202 comprises: the first switch M1, there is first end, the second end and control end, described first end is coupled to the output terminal of sampling hold circuit 201, described control end receives the first control signal GA1, and described the first control signal GA1, when the first power switch MP conducting, controls the first switch M1 closure, when the first power switch MP turn-offs, control the first switch M1 and disconnect; Second switch M2, there is first end, the second end and control end, described first end is coupled to the second end of the first switch M1, described the second end ground connection, described control end receives the second control signal GA2, and described the second control signal GA2, when sampling switch Ms conducting, controls second switch M2 closure, when sampling switch Ms turn-offs, control second switch M2 and disconnect; Low-pass filter circuit 2021, have input end and output terminal, and described input end is coupled to coupling a little of the first switch M1 and second switch M2, described output terminal output detection signal VD.
In one embodiment, described low-pass filter circuit 2021 comprises: resistance R 3, there is first end and the second end, and described first end is coupled to coupling a little of the first switch M1 and second switch M2, and described the second end is coupled to the output terminal of averaging circuit 202; And average capacitance C2, thering is first end and the second end, described first end is coupled to the second end of resistance R 3, described the second end ground connection; Coupling of wherein said resistance R 3 and described average capacitance C2 produces a detection signal VD.
In one embodiment, the first control signal GA1 is identical with the control signal G1 of the first power switch MP; The second control signal GA2 is identical with sampling control signal G2.
The waveform schematic diagram of each signal when Fig. 3 shows inverse-excitation type switch power-supply circuit in Fig. 2 and is operated in the cutout pattern.Wherein Ip is the current waveform that flows through former limit winding L p, and Is is the current waveform that flows through secondary winding L s.Illustrate the principle of work of the voltage detecting circuit 20 in Fig. 2 below in conjunction with Fig. 2 and Fig. 3.
At interval T1, the control signal G1 of the first power switch MP is high level, the first power switch MP conducting, the value of voltage VA is almost 0, the electric current I p that flows through former limit winding L p rises, now sampling control signal G2 is low level, and sampling switch Ms disconnects, and the sampled signal VB of sampling hold circuit 201 outputs keeps initial value.The first control signal GA1 is identical with the control signal G1 of the first power switch MP, the second control signal GA2 is identical with sampling control signal G2, therefore the first switch M1 conducting, second switch M2 disconnects, and the value of the voltage VX of the first switch M1 and second switch M2 tie point equals the value of sampled signal VB.
At interval T2, the control signal G1 of the first power switch MP is low level, and the first power switch MP turn-offs, and the value of voltage VA is
The electric current I p that flows through former limit winding L p is 0, and the electric current I s that flows through secondary winding L s descends, and now sampling control signal G2 is high level, sampling switch Ms closure, and the voltage on sampling capacitance C1 equals the value of voltage division signal VF, that is:
Wherein, the dividing potential drop coefficient that K is bleeder circuit 203,
The first control signal GA1 is identical with the control signal G1 of the first power switch MP, the second control signal GA2 is identical with sampling control signal G2, therefore the first switch M1 disconnects, second switch M2 closure, and the value of the voltage VX of the first switch M1 and second switch M2 tie point equals 0.
At interval T3, the control signal G1 of the first power switch MP is low level, and the first power switch MP turn-offs.Due to inverse-excitation type switch power-supply circuit, in the cutout pattern, the electric current I s that flows through secondary winding L s in this stage reduces to 0.Now sampling control signal G2 is low level, and sampling switch Ms disconnects, and the voltage on sampling capacitance C1 keeps initial value, and the value of sampled signal VB remains unchanged.Now, the first switch M1 and second switch M2 all disconnect, and the value of the voltage VX of the first switch and second switch tie point equates with the value of detection signal VD.
Through the filtering of low-pass filter circuit 2021, the mean value of the voltage VX that the value of detection signal VD is the first switch M1 and second switch M2 tie point.Therefore, in a switch periods, the value of detection signal VD is:
Those of ordinary skills should be understood that under stable situation, in inverse-excitation type switch power-supply circuit,
I1∶I2＝Ns∶Np (5)
L1∶L2＝(Np∶Ns)
2 (6)
Can obtain following formula (7) according to formula (3), (4), (5) and (6):
By in formula (7) substitution formula (2), can obtain:
The value that is detection signal VD is directly proportional to the value of output voltage V o, and voltage detecting circuit 20 has been realized the detection to output voltage V o.
Fig. 4 shows the electrical block diagram according to the buck switching power circuit of the employing voltage detecting circuit 20 of the utility model one embodiment.In Fig. 4, described buck switching power circuit comprises energy-storage travelling wave tube L, and the first power switch MP and the second power switch Ds that couple with energy-storage travelling wave tube T1, and output capacitance Co produce output voltage V o on this output capacitance, drive pull-up resistor RL.Described energy-storage travelling wave tube L comprises inductance.When the first power switch MP conducting, described energy-storage travelling wave tube L is by power source charges, storage power, and described output capacitance Co provides energy to pull-up resistor RL; When the first power switch MP turn-offs, for keeping continuous current mode, the second power switch Ds conducting, the energy be stored in energy-storage travelling wave tube L charges to output capacitance Co and provides energy to pull-up resistor RL.The control signal G1 of described the first power switch MP can be provided by the control circuit of known buck switching power circuit.
In Fig. 4, the input end of described bleeder circuit 203 is coupled to the tie point of energy-storage travelling wave tube L and the first power switch MP, the voltage division signal VF that output terminal output is directly proportional to the voltage VA of the tie point of energy-storage travelling wave tube T1 and the first power switch MP.The input end of sampling hold circuit 201 is coupled to the output terminal of bleeder circuit 203, when the first power switch MP turn-offs, and described sampling hold circuit 201 sampling voltage division signal VF, described output terminal output sampled signal VB; The output terminal that the input end of described averaging circuit 202 is coupled to sampling hold circuit 201 receives sampled signal VB, the detection signal VD that described output terminal output is directly proportional to output voltage V o.
Course of work when below elaboration voltage detecting circuit 20 is applied in the buck switching power circuit.In one embodiment, sampling control signal G2 has characterized the break-make of the second power switch Ds, when the second power switch Ds turn-offs, sampling control signal G2 is in the first signal state, low level for example, when the second power switch Ds conducting, sampling control signal G2 for example, in secondary signal state, high level.
The voltage VA of the tie point that in one embodiment, sampling control signal G2 can be by detecting energy-storage travelling wave tube L and the first power switch MP obtains.When the first power switch MP conducting, the value of voltage VA equals 0; At the first power switch MP, turn-off, during the second power switch Ds conducting, VA=Vin+Vo; When the first power switch MP and the second power switch Ds turn-off simultaneously, the decay of the value starting oscillation of voltage VA.As can be seen here, only, when the second power switch Ds conducting, the value of voltage VA is maximum.Therefore, as long as a comparator circuit is set, the value of voltage VA is compared with Vin+Vo, can obtain sampling control signal G2.In actual applications, due to the moment of all turn-offing at the first power switch MP and the second power switch Ds, therefore the value of voltage VA can drop to the value that approaches 0 within first oscillation period, the value of voltage VA and one can be greater than to 0, and the value that is less than Vin+Vo is compared.The selection of concrete numerical value can decide according to the requirement of practical situations and precision.
In one embodiment, can be by detecting the break-make of the first power switch MP, and the zero crossing that flows through the electric current I L of energy-storage travelling wave tube L obtains sampling control signal G2.For example, when the first power switch MP turn-offs, sampling control signal G2 is effective status from the disarmed state saltus step, and when electric current I L zero passage, sampling control signal G2 is disarmed state from the effective status saltus step.
The waveform schematic diagram of each signal when Fig. 5 shows buck switching power circuit in Fig. 4 and is operated in the cutout pattern.Wherein IL is the current waveform that flows through energy-storage travelling wave tube L.Illustrate voltage detecting circuit 20 below in conjunction with Fig. 4 and Fig. 5 and be applied to the course of work in the buck switching power circuit.
At interval T1, the control signal G1 of the first power switch MP is high level, the first power switch MP conducting, the value of voltage VA is 0, the electric current I L that flows through energy-storage travelling wave tube L rises, now sampling control signal G2 is low level, and sampling switch Ms disconnects, and the sampled signal VB of sampling hold circuit output remains the value of a switch periods.The first control signal GA1 is identical with the control signal G1 of the first power switch MP, the second control signal GA2 is identical with sampling control signal G2, therefore the first switch M1 conducting, second switch M2 disconnects, and the value of the voltage VX of the first switch M1 and second switch M2 tie point equals the value of sampled signal VB.
At interval T2, the control signal G1 of the first power switch MP is low level, the first power switch MP turn-offs, the value of voltage VA is Vin+Vo, the electric current I L that flows through energy-storage travelling wave tube L descends, and now sampling control signal G2 is high level, sampling switch Ms closure, voltage on sampling capacitance C1 equals the value of voltage division signal VF, that is:
Wherein, the dividing potential drop coefficient that K is bleeder circuit 203,
The first control signal GA1 is identical with the control signal G1 of the first power switch MP, the second control signal GA2 is identical with sampling control signal G2, therefore the first switch M1 disconnects, second switch M2 closure, and the value of the voltage VX of the first switch M1 and second switch M2 tie point equals 0.
At interval T3, the control signal G1 of the first power switch MP is low level, and the first power switch MP turn-offs.Due to the buck switching power circuit, in the cutout pattern, the electric current I L that flows through energy-storage travelling wave tube L in this stage reduces to 0.Now sampling control signal G2 is low level, and sampling switch Ms disconnects, and the voltage on sampling capacitance C1 keeps initial value, and the value of sampled signal VB remains unchanged.Now, the first switch M1 and second switch M2 all disconnect, and the value of the voltage VX of the first switch and second switch tie point equates with the value of detection signal VD.
Through the filtering of low-pass filter circuit 2021, the mean value of the voltage VX that the value of detection signal VD is the first switch M1 and second switch M2 tie point.Therefore, in a switch periods, the value of detection signal VD is:
Those of ordinary skills should be understood that under stable situation, and in the buck switching power circuit, the increment of inductive current IL and decrement (for example Δ IL in Fig. 5) equate, can obtain thus:
Vin×T1＝Vo×T2 (11)
By in formula (11) substitution formula (10), can obtain:
VD＝K×Vo (12)
The value that is detection signal VD is directly proportional to the value of output voltage V o.
Although what those of ordinary skills should be understood that above embodiment provides is all the course of work of circuit working in discontinuous current pattern situation, the situation for circuit working under current continuity or critical conditions, voltage detecting circuit 20 also is suitable for.
Those of ordinary skills will be appreciated that, although the utility model has provided the embodiment of voltage detecting circuit 20 for inverse excitation type converter circuit and buck switching power circuit, but voltage detecting circuit 20 is equally applicable to other switching power circuit, such as step-down switching power circuit, boosted switch power circuit, normal shock switching power circuit etc.
Although with reference to several exemplary embodiments, described the utility model, should be appreciated that term used is explanation and exemplary and nonrestrictive term.Because the utility model can specifically be implemented in a variety of forms and not break away from spirit or the essence of utility model, so be to be understood that, above-described embodiment is not limited to any aforesaid details, and explain widely in the spirit and scope that should limit in the claim of enclosing, therefore fall into whole variations in claim or its equivalent scope and remodeling and all should be the claim of enclosing and contain.
Claims (8)
1. a voltage detecting circuit, described voltage detecting circuit can be used for the output voltage of detector switch power circuit, described switching power circuit comprises energy-storage travelling wave tube and the first power switch and the second power switch that couple with energy-storage travelling wave tube, wherein, energy-storage travelling wave tube is storage power when the first power switch conducting, export energy to load when the first power switch turn-offs, it is characterized in that, described voltage detecting circuit comprises:
Sampling hold circuit, have input end and output terminal, and described input end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, described output terminal output sampled signal; And
Averaging circuit, have input end and output terminal, and the output terminal that described input end is coupled to sampling hold circuit receives sampled signal, the detection signal that described output terminal output is directly proportional to the output voltage of switching power circuit.
2. voltage detecting circuit as claimed in claim 1, is characterized in that, described sampling hold circuit comprises:
Sampling switch, there is first end, the second end and control end, described first end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, described control end receives sampling control signal, and described sampling control signal is controlled the sampling switch closure when the first power switch shutoff and the second power switch conducting; And
Sampling capacitance, have first end and the second end, and described first end is coupled to the second end of sampling switch, described the second end ground connection.
3. voltage detecting circuit as claimed in claim 2, is characterized in that, described sampling hold circuit also comprises driver, and described driver is coupled between the output terminal of the first end of sampling capacitance and sampling hold circuit.
4. voltage detecting circuit as claimed in claim 1, it is characterized in that, also comprise bleeder circuit, described bleeder circuit has input end and output terminal, described input end is coupled to the tie point of energy-storage travelling wave tube and the first power switch, the voltage division signal that described output terminal output is directly proportional to the voltage of the tie point of energy-storage travelling wave tube and the first power switch.
5. voltage detecting circuit as claimed in claim 4, is characterized in that, described sampling hold circuit comprises:
Sampling switch, there is first end, the second end and control end, described first end is coupled to the output terminal of bleeder circuit, described control end receives sampling control signal, and described sampling control signal is controlled the sampling switch closure when the first power switch shutoff and the second power switch conducting; And
Sampling capacitance, have first end and the second end, and described first end is coupled to the second end of sampling switch, and described the second end ground connection, produce sampled signal on described first end.
6. voltage detecting circuit as claimed in claim 5, is characterized in that, described sampling hold circuit also comprises driver, and described driver is coupled between the output terminal of the first end of sampling capacitance and sampling hold circuit.
7. voltage detecting circuit as claimed in claim 1, is characterized in that, described averaging circuit comprises:
The first switch, have first end, the second end and control end, described first end is coupled to the output terminal of sampling hold circuit, and described control end receives the first control signal, described the first switch is closure when the first power switch conducting, when the first power switch turn-offs, disconnects;
Second switch, have first end, the second end and control end, and described first end is coupled to the second end of the first switch, described the second end ground connection, described control end receives the second control signal, and described second switch disconnects when the first power switch conducting, closure when the first power switch turn-offs;
Low-pass filter circuit, have input end and output terminal, and described input end is coupled to coupling a little of the first switch and second switch, described output terminal output detection signal.
8. voltage detecting circuit as claimed in claim 7, is characterized in that, described low-pass filter circuit comprises:
Resistance, have first end and the second end, and described first end is coupled to the tie point of the first switch and second switch, and described the second end is coupled to the output terminal of averaging circuit; And
Average capacitance, have first end and the second end, and described first end is coupled to the second end of resistance, described the second end ground connection;
Wherein, coupling of described resistance and average capacitance produces a detection signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220658886 CN202939206U (en) | 2012-12-04 | 2012-12-04 | Voltage detection circuit |
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| CN 201220658886 CN202939206U (en) | 2012-12-04 | 2012-12-04 | Voltage detection circuit |
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| CN202939206U true CN202939206U (en) | 2013-05-15 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102944723A (en) * | 2012-12-04 | 2013-02-27 | 成都芯源系统有限公司 | Voltage detection circuit and voltage detection method |
| CN106610443A (en) * | 2015-10-22 | 2017-05-03 | 群光电能科技股份有限公司 | Alternating current input voltage sensing device |
| CN107733032A (en) * | 2017-10-30 | 2018-02-23 | 华南理工大学 | A kind of boost type wireless charging receiving circuit |
-
2012
- 2012-12-04 CN CN 201220658886 patent/CN202939206U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102944723A (en) * | 2012-12-04 | 2013-02-27 | 成都芯源系统有限公司 | Voltage detection circuit and voltage detection method |
| CN102944723B (en) * | 2012-12-04 | 2015-02-18 | 成都芯源系统有限公司 | Voltage detection circuit and voltage detection method |
| CN106610443A (en) * | 2015-10-22 | 2017-05-03 | 群光电能科技股份有限公司 | Alternating current input voltage sensing device |
| CN106610443B (en) * | 2015-10-22 | 2019-05-24 | 群光电能科技股份有限公司 | AC-input voltage sensing device |
| CN107733032A (en) * | 2017-10-30 | 2018-02-23 | 华南理工大学 | A kind of boost type wireless charging receiving circuit |
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