CN104009643A - Flyback switching power supply of low voltage stress absorption circuit - Google Patents
Flyback switching power supply of low voltage stress absorption circuit Download PDFInfo
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- CN104009643A CN104009643A CN201410187454.4A CN201410187454A CN104009643A CN 104009643 A CN104009643 A CN 104009643A CN 201410187454 A CN201410187454 A CN 201410187454A CN 104009643 A CN104009643 A CN 104009643A
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Abstract
The invention discloses a flyback switching power supply of a low voltage stress absorption circuit. The flyback switching power supply comprises a transformer (T1), a switching tube (Q1), a first RCD absorption circuit (1) and a second RCD absorption circuit (2), wherein the transformer (T1) is provided with a first primary winding (Lp1) and a second primary winding (Lp2), and the first RCD absorption circuit (1) and the second RCD absorption circuit (2) are correspondingly connected to the two ends of the first primary winding (Lp1) and the two ends of the second primary winding (Lp2) in parallel respectively. The flyback switching power supply has the advantages that the two sets of RCD absorption circuits are adopted in the primary windings of the transformer T1, voltage stress of a diode, a resistor and a capacitor in the absorption circuit is effectively reduced, and the condition that voltage stress of the diode is not uniform does not exist.
Description
Technical field
The present invention relates to field of power electronics, more particularly, relate to a kind of inverse-excitation type switch power-supply of low voltage stress absorbing circuit.
Background technology
The advantages such as inverse-excitation type switch power-supply is low with its cost, volume is little, are widely used in the power supply of electronic product.In high input voltage small-power inverse-excitation type switch power-supply system, conventionally select single switch flyback formula Switching Power Supply, consider the factors such as cost, transformer primary side winding adopts RCD absorbing circuit to absorb the energy of transformer primary side leakage inductance, but in the higher occasion of input voltage, this absorbing circuit diode electrically compression is very high, and high-voltage diode is expensive, encapsulation large and switching characteristic is bad, if input voltage is 1000V, diode electrically compression in RCD absorbing circuit will exceed 1300V, need to select diode more than 1500V.In addition, replace single diode by the mode that adopts two diode series connection, although solved the too high problem of diode electrically compression, there is the uneven problem of voltage stress in some extreme occasions in these two diodes, when design, need to leave enough surpluses.
Summary of the invention
The technical problem to be solved in the present invention is, high or have the defect of diode voltage unbalanced stress for diode electrically compression in the above-mentioned existing RCD absorbing circuit of prior art, a kind of inverse-excitation type switch power-supply of low voltage stress absorbing circuit is provided.
The technical solution adopted for the present invention to solve the technical problems is: construct a kind of inverse-excitation type switch power-supply of low voltage stress absorbing circuit, comprise and have the transformer, switching tube of the first former limit winding and the second former limit winding and a corresponding RCD absorbing circuit and the 2nd RCD absorbing circuit that is connected in described the first former limit winding and the second winding two ends, former limit in parallel respectively;
Described transformer, in the time of described switching tube conducting, by the first former limit winding and the second former limit winding storage power, and makes all oppositely cut-offs of diode in diode and described the 2nd RCD absorption circuit in a described RCD absorbing circuit; Described transformer is in the time that described switching tube turn-offs, the energy of described the first former limit winding and the second former limit winding storage is sent to the secondary winding of described transformer, and makes described the first former limit winding and described the second former limit winding by corresponding a RCD absorption circuit and the 2nd RCD absorption circuit afterflow.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, the equal turn numbers of described the first former limit winding and described the second former limit winding, in the time of described switching tube conducting, diode electrically compression in a described RCD absorbing circuit is the capacitance voltage sum in half and a described RCD absorbing circuit of direct-current input power supplying voltage, and the diode electrically compression in described the 2nd RCD absorbing circuit is the capacitance voltage sum in half and described the 2nd RCD absorbing circuit of direct-current input power supplying voltage.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, a described RCD absorbing circuit comprises diode D1, resistance R 4 and capacitor C 3, and described the 2nd RCD absorbing circuit comprises diode D5, resistance R 5 and capacitor C 6; Wherein: the different name end of described the first former limit winding is connected to the positive pole of direct-current input power supplying, the Same Name of Ends of described the first former limit winding is connected to the anode of described diode D1, and described resistance R 4 and described capacitor C 3 are all connected in parallel between the described first different name end of former limit winding and the negative electrode of described diode D1; The different name end of described the second former limit winding is connected to the Same Name of Ends of described the first former limit winding, described second Same Name of Ends of former limit winding and the anodic bonding of described diode D5, described resistance R 5 and described capacitor C 3 are all connected in parallel between the described second different name end of former limit winding and the negative electrode of described diode D5, the drain electrode of described switching tube is connected with the Same Name of Ends of described the second former limit winding, and the source electrode of described switching tube is connected with the negative pole of direct-current input power supplying.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, also comprise the first output circuit and the second output circuit for load current is provided, described the first output circuit comprises diode D3 and capacitor C 4, described the second output circuit comprises diode D4 and capacitor C 5, wherein: described transformer comprises the first secondary winding and the second secondary winding, the Same Name of Ends of described the first secondary winding connects the anode of described diode D3, and described capacitor C 4 is connected in parallel between the negative electrode of described diode D3 and the different name end of described the first secondary winding; The Same Name of Ends of described the second secondary winding connects the anode of described diode D4, and described capacitor C 5 is connected in parallel between the negative electrode of described diode D4 and the different name end of described the second secondary winding.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, also comprise sampling resistor, feedback circuit and control chip, wherein: described sampling resistor is connected between the source electrode of described switching tube and the negative pole of direct-current input power supplying, and for when the described switching tube conducting, by the current sample end that flows through current signal on described the first former limit winding and described the second former limit winding and be converted to the first voltage signal and be sent to described control chip; Described feedback circuit is connected with described the second output circuit, and the second voltage signal of exporting for detection of described the second output circuit the feedback voltage input that is sent to described control chip; Control chip for the pwm signal of exporting corresponding duty ratio according to described the first voltage signal of receiving and described second voltage signal at its output to the grid of described switching tube to control conducting and the shutoff of described switching tube.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, also comprise and be connected to being formed by resistance R 3 and capacitor C 2 between the current sample end of described control chip and described switching tube and the tie point of described sampling resistor, and filter circuit for described the first voltage signal is carried out to filtering.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, also comprise resistance R 1 and capacitor C 1, wherein: described resistance R 1 is connected between the positive pole of direct-current input power supplying and the feeder ear of described control chip, and described capacitor C 1 is connected between the feeder ear of described control chip and the negative pole of described direct-current input power supplying.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, described transformer comprises the 3rd former limit winding, this low voltage stress inverse-excitation type switch power-supply also comprise formed by the 3rd former limit winding, diode and resistance for the power supply circuits of accessory power supply are provided to described control chip after starting at this low voltage stress inverse-excitation type switch power-supply, wherein: described the 3rd Same Name of Ends of former limit winding and the anodic bonding of described diode D2, the negative electrode of described diode D2 is connected to the feeder ear of described control chip through described resistance R 2.
In the inverse-excitation type switch power-supply of above-mentioned low voltage stress absorbing circuit, described switching tube is N-type field effect transistor.
Implement the inverse-excitation type switch power-supply of low voltage stress absorbing circuit of the present invention, there is following beneficial effect: the transformer T1 in this inverse-excitation type switch power-supply comprises the first former limit winding L p1 and the second former limit winding L p2, and be connected in parallel a RCD absorbing circuit and the 2nd RCD absorption circuit of correspondence respectively, the former limit winding that is transformer T1 adopts two groups of RCD absorbing circuits, effectively reduce diode in RCD absorbing circuit, the voltage stress of resistance and electric capacity, and can choose the equal turn numbers of the first former limit winding L p1 and the second former limit winding L p2, guarantee that the diode D1 in a RCD absorbing circuit is under any circumstance almost consistent with the voltage stress of the diode D5 in the 2nd RCD absorbing circuit, there is not the problem of diode voltage unbalanced stress.
Brief description of the drawings
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:
Fig. 1 is the schematic diagram of a kind of inverse-excitation type switch power-supply embodiment of the present invention.
Embodiment
Understand for technical characterictic of the present invention, object and effect being had more clearly, now contrast accompanying drawing and describe the specific embodiment of the present invention in detail.
As shown in Figure 1, be the schematic diagram of a kind of inverse-excitation type switch power-supply embodiment of the present invention, this inverse-excitation type switch power-supply comprises transformer T1, a RCD absorbing circuit 1 and the 2nd RCD absorbing circuit 2, the first output circuit 3 and the second output circuit 4 and switching tube Q1.In the present embodiment, this switching tube Q1 is preferably N-type field effect transistor, this transformer T1 has the first former limit winding L p1 and the second former limit winding L p2 and the first secondary winding L m1 and the second secondary winding L m2, the one RCD absorbing circuit 1 and the 2nd RCD absorbing circuit 2 be the corresponding two ends that are connected in the first former limit winding L p1 and the second former limit winding L p2 in parallel respectively, the first output circuit 3 is connected to the first output winding L m1, and the second output circuit 4 is connected to the second output winding L m2.
Especially, an above-mentioned RCD absorbing circuit 1 comprises that diode D1, resistance R 4 and capacitor C 3, the two RCD absorbing circuits 2 comprise diode D5, resistance R 5 and capacitor C 6; Wherein: the different name end of the first former limit winding L p1 is connected to the positive pole of direct-current input power supplying Vin, the Same Name of Ends of the first former limit winding L p1 is connected to the anode of diode D1, and resistance R 4 and capacitor C 3 are all connected in parallel between the first different name end of former limit winding L p1 and the negative electrode of diode D1; The different name end of the second former limit winding L p2 is connected to the Same Name of Ends of the first former limit winding L p1, the second Same Name of Ends of former limit winding L p2 and the anodic bonding of diode D5, resistance R 5 and capacitor C 3 are all connected in parallel between the second different name end of former limit winding L p2 and the negative electrode of diode D5, the drain electrode of switching tube Q1 is connected with the Same Name of Ends of the second former limit winding L p2, and the source electrode of switching tube Q1 is connected with the negative pole of direct-current input power supplying Vin.
Particularly, in the time of switching tube Q1 conducting, rectifier diode D1 and D5 in two groups of RCD absorbing circuits oppositely end, now transformer T1 is equivalent to a pure inductance, flow through linear rising of electric current of the first former limit winding L p1 and the second former limit winding L p2, transformer T1 is by the first former limit winding L p1 and the second former limit winding L p2 storage power, and the electric capacity of two groups of RCD absorbing circuits is by conductive discharge separately.Now the voltage stress sum of diode D1 and diode D2 is direct-current input power supplying voltage and capacitor C 3 voltages and capacitor C 6 voltage sums, in the present embodiment, for the diode electrically compression that makes a RCD absorption circuit 1 and the 2nd RCD absorption circuit 2 correspondences equates, can choose the first former limit winding L p1 of transformer T1 and the equal turn numbers of the second former limit winding L p2, now the voltage stress of the diode D1 in a RCD absorbing circuit 1 is half and the capacitor C 3 voltage sums of direct-current input power supplying voltage Vin, the voltage stress of diode D5 in the 2nd RCD absorbing circuit 2 is half and the capacitor C 6 voltage sums of direct-current input power supplying voltage Vin.
In the time that switching tube Q1 turn-offs, the voltage of the first former limit winding L p1 and the second former limit winding L p2 and the first secondary winding L m1 and the second secondary winding L m2 is all reverse, transformer T1 is sent to the energy of storage i.e. the first secondary winding L m1 and the second secondary winding L m2 of secondary winding of transformer T1, producing two winding voltages correspondence offers the first output circuit 3 and the second output circuit 4, the first output circuits 3 and the second output circuit 4 load current is provided.Diode D1 in a RCD absorption circuit 1 and the diode D5 conducting in the second absorption circuit 2 simultaneously, the first former limit winding L p1 and the second former limit winding L p2 are by corresponding a RCD absorption circuit 1 and the 2nd RCD absorption circuit 2 afterflows, and a RCD absorption circuit 1 and the 2nd RCD absorption circuit 2 are all for absorbing the upper peak voltage producing of leakage inductance being on the scene effect pipe Q1 because of transformer T1.And because this transformer T1 exists two groups of absorption circuits, now can effectively reduce resistance R 5 in voltage stress and the 2nd RCD absorption circuit 2 of resistance R 4 in a RCD absorbing circuit 1 and capacitor C 3 and the voltage stress of capacitor C 6.
Therefore, even if it is the higher occasion of direct-current input power supplying voltage Vin that this inverse-excitation type switch power-supply is applied in input voltage, but because the former limit winding of transformer T1 adopts two groups of RCD absorbing circuits, effectively reduce the voltage stress of diode, resistance and electric capacity in RCD absorbing circuit, and can choose the equal turn numbers of the first former limit winding L p1 and the second former limit winding L p2, guarantee that under any circumstance the voltage stress of diode D1 and D5 is almost consistent, do not had a problem of diode voltage unbalanced stress.
Above-mentioned the first output circuit 3 comprises diode D3 and capacitor C 4, the second output circuit 4 comprises diode D4 and capacitor C 5, the Same Name of Ends of the first secondary winding L m1 connects the anode of diode D3, and capacitor C 4 is connected in parallel between the negative electrode of diode D3 and the different name end of the first secondary winding L m1; The Same Name of Ends of the second secondary winding L m2 connects the anode of diode D4, and capacitor C 5 is connected in parallel between the negative electrode of diode D4 and the different name end of the second secondary winding L m2.Being on the scene effect pipe Q1 conduction period, the rectifier diode D3 in two groups of output circuits and D4 be oppositely cut-off all, therefore the secondary winding no current of transformer flows through, distinguishes powering load by output capacitance C4 and C5; And in the time that field effect transistor Q1 turn-offs, flow through the current stops of the first former limit winding L p1 and the second former limit winding L p2, all winding voltages are reverse, this flyback voltage makes output diode D3 and D4 and the first secondary winding L m1 and the second secondary winding L m2 conducting, and current flowing, load current is provided.
This inverse-excitation type switch power-supply also comprises sampling resistor Rs, feedback circuit 5, filter circuit 6 and control chip U1, wherein: sampling resistor Rs is connected between the source electrode of switching tube Q1 and the negative pole of direct-current input power supplying Vin, filter circuit 6 comprises resistance R 3 and capacitor C 2, one end of resistance R 3 is connected with the source electrode of switching tube Q1 and the tie point of sampling resistor Rs, the other end of resistance R 3 is connected with the current sample end CS of control chip U1, and the while is through the earth terminal V of capacitor C 2 and control chip U1
gNDconnect.
Above-mentioned sampling resistor Rs is in the time of switching tube Q1 conducting, by the current sample end CS that flows through current signal on the first former limit winding L p1 and the second former limit winding L p2 and be converted to the first voltage signal and be sent to control chip U1 after the filter action of filter circuit 6.Feedback circuit 5 is connected with the output of the second output circuit 4, the second voltage signal of exporting for detection of the second output circuit 4 the feedback voltage input V that is sent to control chip U1
fB.Control chip U1 the first voltage signal that basis receives again and second voltage signal are at its output V
gexport the pwm signal of corresponding duty ratio to the grid of switching tube Q1, thus conducting and the shutoff of control switch pipe Q1, and then stablize the voltage signal of the second output circuit and the output of the first output circuit.
In addition, above-mentioned transformer T1 also comprises the 3rd former limit winding L p3, this inverse-excitation type switch power-supply also comprise for startup afterwards give control chip U1 the power supply circuits 7 of accessory power supply are provided and be connected to the positive pole of direct-current input power supplying Vin and the feeder ear Vcc of control chip U1 between resistance R 1 and be connected to the feeder ear Vcc of control chip U1 and the negative pole of direct-current input power supplying Vin between capacitor C 1.Wherein: the 3rd Same Name of Ends of former limit winding L p3 and the anodic bonding of diode D2, the negative electrode of diode D2 is connected to the feeder ear Vcc of control chip U1 through resistance R 2, in the time that this inverse-excitation type switch power-supply starts, charge to capacitor C 1 by direct-current input power supplying Vin through resistance R 1, when its voltage reaches after the starting resistor of control chip U1, control chip U1 starts working, conducting and the shutoff of control switch pipe Q1, in the time that switching tube Q1 turn-offs, the 3rd former limit winding L p3 conducting of diode D2 in power supply circuits 7 and transformer T1, because of the resistance of resistance R 1 very large, and the switching frequency of switching tube Q1 is very high, therefore only need a starting resistor be provided to this inverse-excitation type switch power-supply by direct-current input power supplying Vin, just power fast to the feeder ear Vcc of control chip U1 through counnter attack diode D2 and current-limiting resistance R2 by the voltage on the 3rd former limit winding L p3 afterwards.
Above-mentioned control chip U1 can be realized by current mode controller UC2843 in the present embodiment, and it is specifically for passing through feedback voltage input V
fBthe second voltage signal that the second output circuit 4 that reception is sent by feedback circuit 5 is exported, this second voltage signal and internal reference voltage are compared to output one level signal, the first voltage signal again this level signal and current sample end CS being sampled compares, thereby exports the pwm signal of corresponding duty ratio with conducting and the shutoff of control switch pipe Q1.
Implement inverse-excitation type switch power-supply of the present invention, this inverse-excitation type switch power-supply is mainly used in this switch power supply system of high input voltage small-power inverse-excitation type, the transformer T1 of this inverse-excitation type switch power-supply comprises the first former limit winding L p1 and the second former limit winding L p2 and a corresponding RCD absorbing circuit and the 2nd RCD absorbing circuit that is connected in the first former limit winding L p1 and the second winding L p2 two ends, former limit in parallel respectively, can effectively reduce the voltage stress of voltage stress, the especially diode of diode, electric capacity and resistance in two groups of absorbing circuits.Especially, can choose the equal turn numbers of the first former limit winding L p1 and the second former limit winding L p2, in the time of switching tube Q1 conducting, diode in two groups of RCD absorbing circuits is in blocking state, the electric capacity of each RCD absorbing circuit is respectively by conductive discharge separately, now each diode electrically compression be the half of DC power supply voltage Vin with RCD absorbing circuit separately in capacitance voltage sum, effectively reduced the voltage stress of each diode in absorption circuit.
In the time that switching tube turn-offs, the first former limit winding L p1 and the second former limit winding L p2, by the afterflow of each self-corresponding RCD absorbing circuit, now can effectively reduce electric capacity, resistance voltage stress in each RCD absorbing circuit.Even if to be therefore applied in input voltage be the higher occasion of direct-current input power supplying voltage Vin to this inverse-excitation type switch power-supply, but because the former limit winding of transformer T1 adopts two groups of RCD absorbing circuits, effectively reduce the voltage stress of diode, resistance and electric capacity in absorbing circuit, and can choose the first former limit winding L
p1 and the equal turn numbers of the second former limit winding L p2, guarantee that under any circumstance the voltage stress of diode D1 and D5 is almost consistent, there is not the problem of diode voltage unbalanced stress.
By reference to the accompanying drawings embodiments of the invention are described above; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment is only schematic; instead of restrictive; those of ordinary skill in the art is under enlightenment of the present invention; not departing from the scope situation that aim of the present invention and claim protect, also can make a lot of forms, within these all belong to protection of the present invention.
Claims (9)
1. the inverse-excitation type switch power-supply of a low voltage stress absorbing circuit, it is characterized in that, comprise have the transformer (T1), switching tube (Q1) of the first former limit winding (Lp1) and the second former limit winding (Lp2) and respectively correspondence be connected in a RCD absorbing circuit (1) and the 2nd RCD absorbing circuit (2) at described the first former limit winding (Lp1) and the second two ends, former limit winding (Lp2) in parallel;
Described transformer (T1) is in the time of described switching tube (Q1) conducting, by the first former limit winding (Lp1) and the second former limit winding (Lp2) storage power, and make all oppositely cut-offs of diode in diode and described the 2nd RCD absorption circuit (2) in a described RCD absorbing circuit (1); Described transformer (T1) is in the time that described switching tube (Q1) turn-offs, the energy of described the first former limit winding (Lp1) and the storage of the second former limit winding (Lp2) is sent to the secondary winding of described transformer (T1), and makes described the first former limit winding (Lp1) and described the second former limit winding (Lp2) by corresponding a RCD absorption circuit (1) and the 2nd RCD absorption circuit (2) afterflow.
2. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 1, it is characterized in that, the equal turn numbers of described the first former limit winding (Lp1) and described the second former limit winding (Lp2), in the time of described switching tube conducting, diode electrically compression in a described RCD absorbing circuit (1) is the capacitance voltage sum in half and a described RCD absorbing circuit (1) of direct-current input power supplying voltage, diode electrically compression in described the 2nd RCD absorbing circuit (2) is the capacitance voltage sum in half and described the 2nd RCD absorbing circuit (2) of direct-current input power supplying voltage.
3. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 1, it is characterized in that, a described RCD absorbing circuit (1) comprises diode D1, resistance R 4 and capacitor C 3, and described the 2nd RCD absorbing circuit (2) comprises diode D5, resistance R 5 and capacitor C 6; Wherein: the different name end of described the first former limit winding (Lp1) is connected to the positive pole of direct-current input power supplying, the Same Name of Ends of described the first former limit winding (Lp1) is connected to the anode of described diode D1, and described resistance R 4 and described capacitor C 3 are all connected in parallel between the described first different name end of former limit winding (Lp1) and the negative electrode of described diode D1; The different name end of described the second former limit winding (Lp2) is connected to the Same Name of Ends of described the first former limit winding (Lp1), described second Same Name of Ends of former limit winding (Lp2) and the anodic bonding of described diode D5, described resistance R 5 and described capacitor C 3 are all connected in parallel between the described second different name end of former limit winding (Lp2) and the negative electrode of described diode D5, the drain electrode of described switching tube (Q1) is connected with the Same Name of Ends of described the second former limit winding (Lp2), and the source electrode of described switching tube (Q1) is connected with the negative pole of direct-current input power supplying.
4. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 1, it is characterized in that, also comprise the first output circuit (3) and the second output circuit (4) for load current is provided, described the first output circuit (3) comprises diode D3 and capacitor C 4, described the second output circuit (4) comprises diode D4 and capacitor C 5, wherein: described transformer (T1) comprises the first secondary winding (Lm1) and the second secondary winding (Lm2), the Same Name of Ends of described the first secondary winding (Lm1) connects the anode of described diode D3, described capacitor C 4 is connected in parallel between the negative electrode of described diode D3 and the different name end of described the first secondary winding (Lm1), the Same Name of Ends of described the second secondary winding (Lm2) connects the anode of described diode D4, and described capacitor C 5 is connected in parallel between the negative electrode of described diode D4 and the different name end of described the second secondary winding (Lm2).
5. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 4, it is characterized in that, also comprise sampling resistor (Rs), feedback circuit (5) and control chip (U1), wherein: described sampling resistor (Rs) is connected between the source electrode and the negative pole of direct-current input power supplying of described switching tube (Q1), and for when described switching tube (Q1) conducting, by the current sample end that flows through current signal on described the first former limit winding (Lp1) and described the second former limit winding (Lp2) and be converted to the first voltage signal and be sent to described control chip (U1), described feedback circuit (5) is connected with described the second output circuit (4), and for detection of the second voltage signal of described the second output circuit (4) output and be sent to the feedback voltage input of described control chip (U1), control chip (U1) for the pwm signal of exporting corresponding duty ratio according to described the first voltage signal of receiving and described second voltage signal at its output to the grid of described switching tube (Q1) to control conducting and the shutoff of described switching tube (Q1).
6. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 5, it is characterized in that, also comprise and be connected to being formed by resistance R 3 and capacitor C 2 between the current sample end of described control chip (U1) and described switching tube (Q1) and the tie point of described sampling resistor (Rs), and for described the first voltage signal being carried out to the filter circuit (6) of filtering.
7. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 5, it is characterized in that, also comprise resistance R 1 and capacitor C 1, wherein: described resistance R 1 is connected between the positive pole of direct-current input power supplying and the feeder ear of described control chip (U1), and described capacitor C 1 is connected between the feeder ear and the negative pole of described direct-current input power supplying of described control chip (U1).
8. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 5, it is characterized in that, described transformer (T1) comprises the 3rd former limit winding (Lp3), this low voltage stress inverse-excitation type switch power-supply also comprises by the 3rd former limit winding (Lp3), diode (D2) and resistance (R2) composition for the power supply circuits (7) of accessory power supply are provided to described control chip (U1) after starting at this low voltage stress inverse-excitation type switch power-supply, wherein: described the 3rd Same Name of Ends of former limit winding (Lp3) and the anodic bonding of described diode D2, the negative electrode of described diode D2 is connected to the feeder ear of described control chip (U1) through described resistance R 2.
9. the inverse-excitation type switch power-supply of low voltage stress absorbing circuit according to claim 1, is characterized in that, described switching tube (Q1) is N-type field effect transistor.
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US10320286B2 (en) | 2016-09-20 | 2019-06-11 | Shenzhen China Star Optoelectronics Technology Co., Ltd | Absorption circuit, feed circuit and liquid crystal display |
CN106655866A (en) * | 2016-12-26 | 2017-05-10 | 威胜集团有限公司 | High-frequency chain-based single-stage type inverter |
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