CN218570096U - Transformer circuit, isolated switching power supply and charger - Google Patents
Transformer circuit, isolated switching power supply and charger Download PDFInfo
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- CN218570096U CN218570096U CN202222471459.2U CN202222471459U CN218570096U CN 218570096 U CN218570096 U CN 218570096U CN 202222471459 U CN202222471459 U CN 202222471459U CN 218570096 U CN218570096 U CN 218570096U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The embodiment of the application discloses transformer circuit, isolated switching power supply and charger, include, main winding circuit, secondary winding circuit and auxiliary winding circuit, the first end of main winding through first electric capacity with the first utmost point of first MOS pipe is connected, the second end of main winding and the second pole of first MOS pipe, the first utmost point of second MOS pipe is connected, the second pole and the first earthing terminal of second MOS pipe are connected, secondary winding circuit includes secondary winding and rectification filter circuit, the fifth end of auxiliary winding is connected with the positive pole of diode, the first end of first resistance is connected with the negative pole of diode, the second end of first resistance is connected with the first end of second electric capacity, the second end of second electric capacity and the sixth end of auxiliary winding all are connected with first earthing terminal. A resistor is arranged between a second capacitor and a diode of the auxiliary winding circuit of the transformer, so that the impedance of a loop where the auxiliary winding is located can be increased, the current of the loop is reduced, and the voltage spike of the secondary side of the transformer can be effectively reduced.
Description
Technical Field
The utility model relates to a transformer technical field, concretely relates to transformer circuit, isolated switching power supply and charger.
Background
With the popularization of high-power small-volume chargers, it is difficult for a conventional DCM (Discontinuous Conduction Mode) to achieve high power density, and the charger needs to operate in a CCM (Continuous Conduction Mode). The charger typically includes a transformer circuit that may include a primary winding capable of high voltage input, a secondary winding capable of outputting a voltage to drive a load, and an auxiliary winding capable of eliminating the third harmonic of the transformer and providing a voltage source and signal for transformer protection. The two ends of the secondary winding are usually connected with a rectifying and filtering circuit with a MOS tube, which is easy to cause voltage spike of the MOS tube and even exceed the safety specification when the charger works in CCM mode. Accordingly, there is a need for a transformer circuit that effectively reduces or eliminates voltage spikes.
SUMMERY OF THE UTILITY MODEL
The main objective of the present invention is to provide a transformer circuit and an isolated switching power supply capable of reducing or eliminating secondary voltage spikes.
In order to achieve the above object, an embodiment of the present invention provides a transformer circuit, including,
the main winding circuit comprises a main winding, a first MOS (metal oxide semiconductor) transistor, a second MOS transistor and a first capacitor, wherein a first end of the main winding is connected with a first pole of the first MOS transistor through the first capacitor, a second end of the main winding is connected with a second pole of the first MOS transistor and the first pole of the second MOS transistor, a second pole of the second MOS transistor is connected with a first grounding terminal, and a control pole of the first MOS transistor and a control pole of the second MOS transistor can receive a switch control signal;
the secondary winding circuit comprises a secondary winding and a rectifying and filtering circuit, and the third end and the fourth end of the secondary winding are connected with the rectifying and filtering circuit; and a (C) and (D) and,
the auxiliary winding circuit comprises an auxiliary winding, a diode, a first resistor and a second capacitor, wherein a fifth end of the auxiliary winding is connected with the anode of the diode, a first end of the first resistor is connected with the cathode of the diode, a second end of the first resistor is connected with a first end of the second capacitor, and a second end of the second capacitor and a sixth end of the auxiliary winding are connected with the first grounding end.
In some embodiments, the first MOS transistor is an N-type MOS transistor, the first pole of the first MOS transistor is a drain, the second pole of the first MOS transistor is a source, and the control pole of the first MOS transistor is a gate.
In some embodiments, the second MOS transistor is an N-type MOS transistor, the first pole of the second MOS transistor is a drain, the second pole of the second MOS transistor is a source, and the control pole of the second MOS transistor is a gate.
In some embodiments, the auxiliary winding is located between the main winding and the secondary winding, and the auxiliary winding is in close proximity to the main winding.
In some embodiments, the rectifying-filtering circuit includes:
a second pole of the third MOS tube is connected with a third end of the secondary winding;
the anode of the electrolytic capacitor is connected with the first electrode of the third MOS tube, and the cathode of the electrolytic capacitor and the fourth end of the secondary winding are both connected with a second grounding end;
and the first end of the resistor is connected with the first pole of the third MOS tube, and the second end of the resistor is connected with the second grounding end.
In some embodiments, the third MOS transistor is an N-type MOS transistor, the first pole of the third MOS transistor is a drain, the second pole of the third MOS transistor is a source, and the control pole of the third MOS transistor is a gate.
The embodiment of the utility model provides a still provide an isolated switching power supply, including transformer, switching control circuit and drive control circuit, the transformer includes:
the main winding circuit comprises a main winding, a first MOS (metal oxide semiconductor) transistor, a second MOS transistor and a first capacitor, wherein a first end of the main winding is connected with a first pole of the first MOS transistor through the first capacitor, a second end of the main winding is connected with a second pole of the first MOS transistor and a first pole of the second MOS transistor, a second pole of the second MOS transistor is connected with a first grounding terminal, and a control pole of the first MOS transistor and a control pole of the second MOS transistor are respectively connected with the corresponding switch control circuits;
the secondary winding circuit comprises a secondary winding and a rectification filter circuit, and the third end and the fourth end of the secondary winding are connected with the rectification filter circuit; and a process for the preparation of a coating,
the auxiliary winding circuit comprises an auxiliary winding, a diode, a first resistor and a second capacitor, wherein a fifth end of the auxiliary winding is connected with an anode of the diode, a first end of the first resistor is connected with a cathode of the diode, a second end of the first resistor is connected with a first end of the second capacitor, and a second end of the second capacitor and a sixth end of the auxiliary winding are connected with the first grounding end.
In some embodiments, the rectifying-filtering circuit includes:
a second pole of the third MOS transistor is connected with a third end of the secondary winding, and a control pole of the third MOS transistor is connected with the driving control circuit;
the anode of the electrolytic capacitor is connected with the first electrode of the third MOS tube, and the cathode of the electrolytic capacitor and the fourth end of the secondary winding are both connected with a second grounding end;
and the first end of the resistor is connected with the first pole of the third MOS tube, and the second end of the resistor is connected with the second grounding end.
In some embodiments, the first MOS transistor, the second MOS transistor and the third MOS transistor are N-type MOS transistors, the first pole is a drain of the N-type MOS transistor, the second pole is a source, and the control pole is a gate.
The embodiment of the utility model provides a still provide a charger, include transformer circuit.
In the technical scheme of the utility model, a resistor is arranged between the second capacitor and the diode of the transformer auxiliary winding circuit, so that the impedance of a loop where the auxiliary winding is arranged can be increased, the loop current is reduced, and the change rate of the voltage Vds at the two ends of the second MOS tube is further reduced, thereby effectively reducing the voltage peak of the parasitic diode of the third MOS tube of the secondary winding circuit; because the secondary voltage spike can be reduced, the MOS tube with relatively low voltage resistance can be selected, and the cost can be effectively saved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a schematic circuit diagram of a transformer circuit of the present embodiment (without a first resistor);
FIG. 2 is a schematic diagram of the equivalent circuit of FIG. 1;
FIG. 3 is the schematic of FIG. 2 with the auxiliary winding leakage inductance omitted;
fig. 4 is a timing diagram of switching control of the first MOS transistor and the second MOS transistor in the present embodiment, wherein the abscissa represents time, dr-Q2 represents a timing diagram of switching of the second MOS transistor, dr-Q1 represents a timing diagram of switching of the first MOS transistor, and Q2-Vds represents a schematic diagram of variation of voltage Vds across the second MOS transistor;
fig. 5 is a schematic diagram illustrating a variation of the voltage Vds across the second MOS transistor in this embodiment;
FIG. 6 is a schematic circuit diagram of a transformer circuit according to the present embodiment;
FIG. 7 is an equivalent circuit schematic of FIG. 6;
fig. 8 is a schematic diagram illustrating a variation of the voltage Vds across the second MOS transistor in fig. 7.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as up, down, left, right, front, back \8230;) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.
In addition, the technical solutions between the embodiments of the present invention can be combined with each other, but it is necessary to be able to be realized by a person having ordinary skill in the art as a basis, and when the technical solutions are contradictory or cannot be realized, the combination of such technical solutions should be considered to be absent, and is not within the protection scope of the present invention.
As shown in fig. 1, the transformer circuit includes a main winding circuit, a secondary winding circuit, and an auxiliary winding circuit. The main winding circuit and the auxiliary winding circuit may be provided on a primary side of the transformer, the main winding circuit being capable of receiving an input voltage. A secondary winding circuit may be provided on the secondary side of the transformer, the secondary winding circuit providing an output voltage to the load. The main winding circuit comprises a main winding TA, a first capacitor Cr, a first MOS tube Q1 and a second MOS tube Q2. The first end of the first capacitor Cr is connected with the first end of the main winding TA, the second end of the first capacitor Cr is connected with the first pole D of the first MOS transistor Q1, the second pole S of the first MOS transistor Q1 is connected with the second end of the main winding TA, the first pole D of the second MOS transistor Q2 is connected with the second end of the main winding TA, the second pole S of the second MOS transistor Q2 is connected with the first grounding terminal PGND, the first grounding terminal PGND can be grounded, that is, the first capacitor Cr and the first MOS transistor Q1 are connected in series between the first end and the second end of the main winding TA, and the second MOS transistor Q2 is arranged between the second end of the main winding TA and the first grounding terminal PGND.
The secondary winding circuit comprises a secondary winding TB, a third MOS tube Q3, an electrolytic capacitor Co and a resistor R. The second pole S of the third MOS transistor Q3 is connected to the third end of the secondary winding TB, the fourth end of the secondary winding TB is connected to the second ground GND, and the second ground GND may be grounded. The anode of the electrolytic capacitor Co is connected with the first electrode D of the third MOS transistor Q3, and the cathode of the electrolytic capacitor Co is connected with the second ground GND. A first end of the resistor R is connected to the first pole D of the third MOS transistor Q3, and a second end of the resistor R is connected to the second ground terminal GND, that is, the electrolytic capacitor Co and the resistor R are connected in parallel between the first pole D of the third MOS transistor Q3 and the second ground terminal GND. The fourth terminal of the secondary winding TB and the first terminal of the main winding TA may be dotted terminals. The third terminal of the secondary winding TB and the second terminal of the main winding TA may be terminals of the same name.
The auxiliary winding circuit comprises an auxiliary winding TC, a diode D1 and a second capacitor Ca, a fifth end of the auxiliary winding TC is connected with an anode of the diode D1, a cathode of the diode D1 is connected with a first end of the second capacitor Ca, a second end of the second capacitor Ca and a sixth end of the auxiliary winding TC are both connected with a first grounding end PGND, namely, the diode D1 and the second capacitor Ca are connected between the fifth end and the sixth end of the auxiliary winding TC in series.
The first MOS transistor Q1, the second MOS transistor Q2 and the third MOS transistor Q3 may all be N-type MOS transistors, the first pole D thereof is a drain, the second pole S thereof is a source, and the control pole G thereof is a gate.
As shown in fig. 2, which is an equivalent circuit of the transformer circuit shown in fig. 1. The equivalent circuit comprises an excitation inductance Lm, a main winding leakage inductance Lkp, a secondary winding leakage inductance Lks, an auxiliary winding leakage inductance Lka, a first capacitor Cr, a first MOS tube Q1, a second MOS tube Q2, an equivalent electrolytic capacitor Co ', an equivalent resistor R', a diode D1 and a second capacitor Ca. The main winding leakage inductance Lkp, the first capacitor Cr and the first MOS transistor Q1 are sequentially connected in series between the first end and the second end of the excitation inductance Lm, wherein the first end of the main winding leakage inductance Lkp and the first end of the excitation inductance Lm are connected at a first node P, the second end of the main winding leakage inductance Lkp is connected with the first end of the first capacitor Cr, the second end of the first capacitor Cr is connected with the first pole D of the first MOS transistor Q1, and the second pole S of the first MOS transistor Q1 and the second end of the excitation inductance Lm are connected at a second node Q. A first pole D of the second MOS transistor Q2 is connected to the second node Q, and a second pole S of the second MOS transistor Q2 is connected to the first ground terminal PGND. The first MOS transistor Q1 may have a parasitic diode, an anode of which is connected to the second pole S of the first MOS transistor Q1, and a cathode of which is connected to the first pole D of the first MOS transistor Q1. The second MOS transistor Q2 may have a parasitic diode having an anode connected to the second pole S of the second MOS transistor Q2 and a cathode connected to the first pole D of the second MOS transistor Q2.
The equivalent electrolytic capacitor Co 'and the equivalent resistor R' are connected in parallel and then connected in series with the leakage inductance Lks of the secondary winding and the third MOS tube Q3 between the first node P and the second node Q, namely between the first end and the second end of the excitation inductance Lm. The cathode of the equivalent electrolytic capacitor Co 'is connected with the first node P, the anode of the equivalent electrolytic capacitor Co' is connected with the first end of the leakage inductance Lks of the secondary winding, the second end of the leakage inductance Lks of the secondary winding is connected with the first pole D of the third MOS transistor Q3, and the second pole S of the third MOS transistor Q3 is connected with the second node Q; a first end of the equivalent resistor R 'is connected to the first node P and a second end of the equivalent resistor R' is connected to a first end of the secondary winding leakage inductance Lks. The third MOS transistor Q3 may have a parasitic diode, an anode of which is connected to the second pole S of the third MOS transistor Q3, and a cathode of which is connected to the first pole D of the third MOS transistor Q3.
The diode D1, the auxiliary winding leakage inductance Lka, and the second capacitor Ca are connected in series between the first node P and the second node Q. The anode of the diode D1 is connected to the second node Q, the cathode of the diode D1 is connected to the first end of the auxiliary winding leakage inductance Lka, the second end of the auxiliary winding leakage inductance Lka is connected to the first end of the second capacitor Ca, and the second end of the second capacitor Ca is connected to the first node P.
Since the auxiliary winding TC and the main winding TA both belong to the primary side of the transformer, and the auxiliary winding TC is closely attached to the main winding TA during winding, the leakage inductance Lka of the auxiliary winding is very small and much smaller than the leakage inductance Lks of the secondary winding, so that the leakage inductance Lka of the auxiliary winding can be ignored to obtain an equivalent circuit as shown in fig. 3.
As shown in fig. 4, it is a timing diagram of switching control of the first MOS transistor Q1 and the second MOS transistor Q2. Dr-Q1 represents a switching control timing chart of the first MOS transistor Q1, dr-Q2 represents a driving switching control timing chart of the second MOS transistor Q2, and Q2-Vds represents a change schematic diagram of voltage Vds at two ends of the second MOS transistor Q2.
As shown in fig. 3 and 4, at time t0, the first MOS transistor Q1 and the second MOS transistor Q2 are both turned off, the main winding leakage inductance Lkp charges the first capacitor Cr through the parasitic diode of the first MOS transistor Q1 and the first MOS transistor Q1, and in this process, a current flows into the first capacitor Cr through the main winding leakage inductance Lkp, the excitation inductance Lm, and the first MOS transistor Q1, thereby charging the first capacitor Cr, wherein when the first MOS transistor Q1 is turned off, the parasitic diode of the first MOS transistor Q1 is turned on, and a current flows from the second diode S of the first MOS transistor Q1 into the first pole D directly through the parasitic diode. At the time t1, the second MOS transistor Q2 is kept off, the first MOS transistor Q1 is switched from off to on, the first pole D and the second pole S of the first MOS transistor Q1 are on, current can flow into the second pole S through the first pole D, the first capacitor Cr starts to discharge, and since the excitation inductance Lm is very large, the discharge current cannot flow through the excitation inductance Lm, and the excitation inductance Lm can be regarded as an open circuit; energy of the first capacitor Cr forms a loop through a first current Ir1 and a second current Ir2, and the first current Ir1 flows through a third MOS transistor Q3, a secondary winding leakage inductance Lks, an equivalent electrolytic capacitor Co 'and an equivalent resistor R' which are connected in parallel and form a first current loop; the second current Ir2 flows through the diode D1 and the second capacitor Ca and forms a second current loop.
At the time t2, after the first MOS transistor Q1 is turned off and before the second MOS transistor Q2 is turned on, the first current Ir1 and the second current Ir2 may continue to pull down the voltage Vds at the two ends of the second MOS transistor Q2 because the current cannot suddenly change. The energy of the pull-down is equal to 1/2 Lkp (Ir 1+ Ir 2) 2 +1/2*Lkp*Ir1 2 The waveform of the voltage Vds across the second MOS transistor is shown in fig. 5.
Since the loop impedance of the second current loop is relatively low, the second current Ir2 is relatively high, the sum of the first current Ir1 and the second current Ir2 is limited by the energy stored on the first capacitor Cr, and the second current Ir2 is larger than the first current Ir1, so 1/2 lkp (Ir 1+ Ir 2) 2 +1/2*Lkp*Ir1 2 The energy of (2) is smaller. At the time t3, the voltage Vds across the second MOS transistor Q2 is still large, so Δ V/Δ t is large, and the voltage Vds is coupled to the secondary winding TB through the transformer, so that the parasitic diode of the third MOS transistor Q3 generates a large peak correspondingly, and in order to reduce the peak, Δ V/Δ t needs to be reduced, and the conduction time can be reduced by reducing the primary side drive, i.e., Δ V/Δ t is reduced by increasing Δ t, but the efficiency is seriously affected by the method.
The present embodiment adopts a method of reducing Δ V. Specifically, to decrease Δ V, the pull-down energy needs to be increased, i.e., by 1/2 lkp (Ir 1+ Ir 2) 2 +1/2*Lkp*Ir1 2 Because Ir1+ Ir2 is limited by the energy stored in the first capacitor Cr, ir1+ Ir2 is basically unchanged, so that only the first current Ir1 can be increased, a proper first resistor R1 is connected in series between the diode D1 and the second capacitor Ca of the second current loop to increase the loop impedance of the second current loop, so that the second current Ir2 is far smaller than the first current Ir1, and thereforeCompared with the case of not increasing the first resistor R1, the first current Ir1 increases, 1/2 × lkp (Ir 1+ Ir 2) 2+1/2 × lkp × ir12 also increases, the voltage Vds across the second MOS transistor Q2 is pulled to be low at time t3, Δ V decreases, Δ V/Δ t changes, and the voltage spike of the parasitic diode of the third MOS transistor Q3 also decreases accordingly, as shown in fig. 8.
As shown in fig. 6, the transformer circuit with the added first resistor R1 is that the first resistor R1 is disposed between the diode D1 and the second capacitor Ca, the cathode of the diode D1 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is connected to the second capacitor Ca, that is, the diode D1, the first resistor R1, and the second capacitor Ca are sequentially connected in series between the fifth end and the sixth end of the auxiliary winding TC. The first resistor R1 may include only one resistor or a plurality of resistors. When a plurality of resistors are arranged, the resistors can be arranged in parallel, and two ends of the plurality of resistors arranged in parallel are respectively connected with the diode D1 and the second capacitor Ca; the resistors can be arranged in series, and two ends of the plurality of resistors arranged in series are respectively connected with the diode D1 and the second capacitor Ca; the resistors may be arranged in parallel, and both ends of the plurality of resistors arranged in parallel are connected to the diode D1 and the second capacitor Ca, respectively.
The equivalent circuit of the transformer circuit after adding the first resistor R1 is shown in fig. 7, and the first resistor R1 is disposed between the diode D1 and the second capacitor Ca.
For the transformer circuit, the third MOS transistor Q3, the electrolytic capacitor Co connected in parallel, and the resistor R constitute a rectifying and filtering circuit, and the rectifying and filtering circuit is connected to the secondary winding TB. The magnetic energy of the main winding TA can be converted into electric energy, so that the secondary winding TB is coupled out of the electric energy, and therefore alternating current is output to the rectifying and filtering circuit. The magnitude of the output alternating voltage is determined by the conduction time of the third MOS transistor Q3, so that the output voltage of the secondary winding TB can be kept stable by controlling the conduction time of the third MOS transistor Q3. In an alternative structure, the rectifying and filtering circuit may only include a third MOS transistor Q3 and an electrolytic capacitor Co, a second pole S of the third MOS transistor Q3 is connected to the third end of the secondary winding TB, a first pole D of the third MOS transistor Q3 is connected to the positive pole of the electrolytic capacitor Co, and a negative pole of the electrolytic capacitor Co and a fourth pole of the secondary winding TB are both connected to the second ground GND.
The transformer circuit can be applied to an isolated switching power supply or a charger. The isolated switching power supply can include a switch control circuit, a drive control circuit, and the transformer circuit. The control electrode G of the first MOS transistor Q1 and the control electrode G of the second MOS transistor Q2 may be connected to the corresponding switch control circuit. The switch control circuit may provide a PWM signal. The PWM signal may include an active portion and an inactive portion, the active portion and the inactive portion forming a switching period, and a proportion of the active portion to the entire switching period is referred to as a duty cycle. Taking the N-type MOS transistor as an example, the high level part of the PWM signal is active, and the low level part is inactive. Generally, the active means that the MOS transistor is turned on, and the inactive means that the MOS transistor is turned off, that is, when the switch control circuit outputs a high level signal, the N-type MOS transistor is turned on, and when a low level signal is output, the N-type MOS transistor is turned off. For the P-type MOS transistor, the low level signal of the PWM signal is active and the high level part of the PWM signal is inactive. Namely, when the switch control circuit outputs a low level signal, the P-type MOS tube is conducted, and when the switch control circuit outputs a high level signal, the P-type MOS tube is turned off. The driving control circuit is connected to the control electrode G of the third MOS transistor Q3 of the transformer circuit, and the driving control circuit adjusts the output voltage of the secondary winding TB by controlling the on-time of the third MOS transistor Q3.
The above only is the preferred embodiment of the present invention, not so limiting the patent scope of the present invention, all under the conception of the present invention, the equivalent structure transformation made by the contents of the specification and the drawings is utilized, or the direct/indirect application is included in other related technical fields in the patent protection scope of the present invention.
Claims (10)
1. A transformer circuit, comprising,
the main winding circuit comprises a main winding, a first MOS (metal oxide semiconductor) transistor, a second MOS transistor and a first capacitor, wherein a first end of the main winding is connected with a first pole of the first MOS transistor through the first capacitor, a second end of the main winding is connected with a second pole of the first MOS transistor and a first pole of the second MOS transistor, a second pole of the second MOS transistor is connected with a first grounding terminal, and a control pole of the first MOS transistor and a control pole of the second MOS transistor can receive a switch control signal;
the secondary winding circuit comprises a secondary winding and a rectifying and filtering circuit, and the third end and the fourth end of the secondary winding are connected with the rectifying and filtering circuit; and a process for the preparation of a coating,
the auxiliary winding circuit comprises an auxiliary winding, a diode, a first resistor and a second capacitor, wherein a fifth end of the auxiliary winding is connected with the anode of the diode, a first end of the first resistor is connected with the cathode of the diode, a second end of the first resistor is connected with a first end of the second capacitor, and a second end of the second capacitor and a sixth end of the auxiliary winding are connected with the first grounding end.
2. The transformer circuit of claim 1, wherein the first MOS transistor is an N-type MOS transistor, the first pole of the first MOS transistor is a drain, the second pole of the first MOS transistor is a source, and the control pole of the first MOS transistor is a gate.
3. The transformer circuit of claim 2, wherein the second MOS transistor is an N-type MOS transistor, the first pole of the second MOS transistor is a drain, the second pole of the second MOS transistor is a source, and the control pole of the second MOS transistor is a gate.
4. The transformer circuit of claim 1, wherein the auxiliary winding is located between the main winding and the secondary winding, and wherein the auxiliary winding is proximate to the main winding.
5. The transformer circuit of claim 1, wherein the rectifying-filtering circuit comprises:
a second pole of the third MOS tube is connected with a third end of the secondary winding;
the anode of the electrolytic capacitor is connected with the first electrode of the third MOS tube, and the cathode of the electrolytic capacitor and the fourth end of the secondary winding are both connected with a second grounding end;
and a first end of the resistor is connected with the first pole of the third MOS tube, and a second end of the resistor is connected with the second grounding terminal.
6. The transformer circuit of claim 5, wherein the third MOS transistor is an N-type MOS transistor, the first pole of the third MOS transistor is a drain, the second pole of the third MOS transistor is a source, and the control pole of the third MOS transistor is a gate.
7. An isolated switching power supply, comprising a transformer, a switching control circuit and a driving control circuit, the transformer comprising:
the main winding circuit comprises a main winding, a first MOS (metal oxide semiconductor) transistor, a second MOS transistor and a first capacitor, wherein a first end of the main winding is connected with a first pole of the first MOS transistor through the first capacitor, a second end of the main winding is connected with a second pole of the first MOS transistor and a first pole of the second MOS transistor, a second pole of the second MOS transistor is connected with a first grounding terminal, and a control pole of the first MOS transistor and a control pole of the second MOS transistor are respectively connected with the corresponding switch control circuits;
the secondary winding circuit comprises a secondary winding and a rectification filter circuit, and the third end and the fourth end of the secondary winding are connected with the rectification filter circuit; and a process for the preparation of a coating,
the auxiliary winding circuit comprises an auxiliary winding, a diode, a first resistor and a second capacitor, wherein a fifth end of the auxiliary winding is connected with the anode of the diode, a first end of the first resistor is connected with the cathode of the diode, a second end of the first resistor is connected with a first end of the second capacitor, and a second end of the second capacitor and a sixth end of the auxiliary winding are connected with the first grounding end.
8. The isolated switching power supply of claim 7, wherein said rectifying and filtering circuit comprises:
a second pole of the third MOS tube is connected with a third end of the secondary winding, and a control pole of the third MOS tube is connected with the driving control circuit;
the anode of the electrolytic capacitor is connected with the first electrode of the third MOS tube, and the cathode of the electrolytic capacitor and the fourth end of the secondary winding are both connected with a second grounding end;
and the first end of the resistor is connected with the first pole of the third MOS tube, and the second end of the resistor is connected with the second grounding end.
9. The isolated switching power supply of claim 8, wherein the first MOS transistor, the second MOS transistor and the third MOS transistor are N-type MOS transistors, the first pole is a drain of the N-type MOS transistor, the second pole is a source of the N-type MOS transistor, and the control pole is a gate of the N-type MOS transistor.
10. A charger, characterized by comprising a transformer circuit according to any one of claims 1-6.
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| CN202222471459.2U CN218570096U (en) | 2022-09-16 | 2022-09-16 | Transformer circuit, isolated switching power supply and charger |
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| CN202222471459.2U CN218570096U (en) | 2022-09-16 | 2022-09-16 | Transformer circuit, isolated switching power supply and charger |
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2022
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