CN217134168U - Transformer circuit and transformer system - Google Patents

Abstract

The application discloses transformer circuit and transformer system, transformer circuit include power management unit, connect electric unit, power supply unit and output unit. The power connection unit comprises a primary winding and a first switching tube, wherein the first end of the primary winding is used for connecting power voltage, the second end of the primary winding is electrically connected with the first end of the first switching tube, and the control end of the first switching tube is electrically connected with the power management unit. The power supply unit is provided with a power supply end, the power supply end is electrically connected with the power management unit to supply power to the power management unit, and the power supply unit comprises a power supply winding. The output unit is used for outputting voltage and comprises a secondary winding. Wherein, the winding directions of the primary winding and the power supply winding are the same. In the embodiment of the application, the mode that the primary winding and the power supply winding are conducted in the same phase to supply power is adopted, the range span of the power supply voltage of the power supply winding can be reduced, the voltage stress of corresponding elements in a circuit is reduced, and the possibility of overvoltage protection of a trigger circuit is reduced.

Description

Transformer circuit and transformer system

Technical Field

The utility model relates to a transformer technical field especially relates to a transformer circuit and transformer system.

Background

In the related art, a transformer may include a primary winding, a secondary winding, and an auxiliary winding for supplying power to a power management unit in the transformer. However, with the rapid development of fast charging sources such as power transmission in recent two years, the range of the output voltage of the transformer is greatly expanded, so that the voltage range of the auxiliary winding is also enlarged, and corresponding elements in a transformer power supply circuit may be damaged.

SUMMERY OF THE UTILITY MODEL

The utility model provides a transformer circuit and transformer system can be so that auxiliary winding's voltage range span reduces, and reduces the voltage stress of corresponding component among the power supply unit, reduces the possibility that triggers power supply unit overvoltage protection.

In a first aspect, an embodiment of the present application provides a transformer circuit, including: the power supply comprises a power supply management unit, a power connection unit, a power supply unit and an output unit.

Specifically, the power connection unit comprises a primary winding and a first switch tube, a first end of the primary winding is used for connecting a power supply voltage, a second end of the primary winding is electrically connected with a first end of the first switch tube, and a control end of the first switch tube is electrically connected with the power management unit. The power supply unit is provided with a power supply end, the power supply end is electrically connected with the power supply management unit to supply power to the power supply management unit, and the power supply unit comprises a power supply winding. The output unit is used for outputting voltage and comprises a secondary winding. And the winding directions of the primary winding and the power supply winding are the same.

In some embodiments of the present application, the power supply unit further includes a first capacitor, a first plate of the first capacitor is electrically connected to a first end of the power supply winding at a first node, and the first node is electrically connected to the power management unit; the second pole plate of the first capacitor and the second end of the power supply winding are electrically connected to a second node, and the second node is grounded.

Based on the above embodiment, after the primary winding and the power supply winding are simultaneously turned on, the power supply winding generates an induced voltage, and the power supply winding can charge the first capacitor, so that the power supply unit can subsequently provide a starting voltage for the power management unit through the first capacitor.

In some embodiments of the present application, the power supply unit further includes a first diode connected in series between the power supply winding and the first node, an anode of the first diode and the first end of the power supply winding are electrically connected to a third node, and a cathode of the first diode is electrically connected to the first node.

Based on the above embodiment, the first diode can ensure that the current is conducted from the third node to the first node in a single direction after the power supply winding generates the induced voltage, so that the current can be prevented from flowing back from the first node to the third node after the first capacitor is connected to the voltage.

In some embodiments of the present application, the power supply unit further includes a first resistor and a second resistor, a first end of the first resistor is electrically connected to the third node, a second end of the first resistor is electrically connected to a fourth node with a first end of the second resistor, the fourth node is electrically connected to the power management unit, and a second end of the second resistor is electrically connected to the second node.

Based on the above embodiment, the first resistor and the second resistor may receive the voltage across the power supply winding, and provide the detection signal to the power management unit based on the voltage value across the power supply winding. When the power supply management unit detects that the power supply voltage drops to a certain value and is not enough to enable the power supply management unit to generate a signal for controlling the circuit switch, the circuit stops working.

In some embodiments of the present application, the power connection unit further includes a third resistor, a first end of the third resistor and a second end of the first switch tube are electrically connected to a fifth node, a second end of the second resistor is grounded, and the fifth node is electrically connected to the power management unit.

Based on the above embodiment, when the power management unit outputs a high level signal to the first switching tube, the first switching tube is turned on, the first end of the primary winding is connected to a power voltage, the primary winding stores energy, and when the power management unit detects that the voltage value of the third resistor is greater than or equal to a preset voltage, the power management unit outputs a low level signal to the first switching tube, so that the first switching tube is turned off.

In some embodiments of the present application, the output unit further includes a second switching tube, a control end of the second switching tube is electrically connected to the power management unit, a first end of the second switching tube is electrically connected to a second end of the secondary winding, the second end of the second switching tube and the first end of the secondary winding are electrically connected to a sixth node, and the sixth node is grounded.

Based on the above embodiment, when the first switching tube is turned on and the power connection unit is turned on, the power management unit sends a low-level voltage signal to the control end of the second switching tube, so that the voltage of the control end of the second switching tube is smaller than the starting voltage of the second switching tube, the second switching tube is in a cut-off region, and the output unit is in a turn-off state; when the first switch tube is turned off, the power management unit sends a high-level voltage signal to the control end of the second switch tube, so that the voltage of the control end of the second switch tube is greater than or equal to the starting voltage of the second switch tube, the second switch tube is in a saturation region, and the output unit is in a conducting state.

Or, in some embodiments of the present application, the output unit further includes a second diode, an anode of the second diode is electrically connected to the first end of the secondary winding, a cathode of the second diode is electrically connected to a seventh node with the second end of the secondary winding, and the seventh node is grounded.

Based on the above embodiment, when the first switching tube is turned on, the power connection unit is turned on, a current flows in the primary winding, and since the winding directions of the primary winding and the secondary winding are opposite and the phases of the primary winding and the secondary winding are opposite, the current of the secondary winding flows from the cathode of the second diode to the anode of the second diode at this time, the second diode of the output unit is reversely biased and is turned off, and the output unit is turned off. When the first switching tube is turned off, the primary winding generates a reverse potential, at the moment, the current of the secondary winding flows from the anode of the second diode to the cathode direction, the second diode of the output unit is conducted in the forward direction, and then the output unit is conducted.

In some embodiments of the present application, the output unit further includes a second capacitor, and when the output unit includes the second switching tube, a first plate of the second capacitor is electrically connected to the first end of the secondary winding, and a second plate of the second capacitor is electrically connected to the sixth node; when the output unit comprises the second diode, the first plate of the second capacitor and the cathode of the second diode are electrically connected to an eighth node, and the second plate of the second capacitor is electrically connected to the seventh node. The second capacitor is used for filtering alternating current components, so that the output direct current is smoother, and voltage can be output to a load.

In some embodiments of the present application, the output unit further includes a feedback unit, when the output unit includes the second switching tube, an input end of the feedback unit is electrically connected to a control end of the second switching tube, and an output end of the feedback unit is electrically connected to the power management unit; when the output unit comprises the second diode, the input end of the feedback unit is electrically connected with the eighth node, and the output end of the feedback unit is electrically connected with the power management unit. The power management unit detects a voltage signal in the output unit through the feedback unit so as to control the power management unit to switch on or off the first switch tube.

In some embodiments of the present application, the transformer circuit further includes a fourth resistor, the fourth resistor is connected in series between the ninth node and the power supply terminal, and a resistance of the fourth resistor is greater than 2 megaohms.

Based on the above embodiment, in the initial stage of the power management unit starting, the rectifying unit inputs a voltage, the input voltage may charge the first capacitor through the fourth resistor, and the input voltage may further input a starting voltage to the power management unit through the fourth resistor. The resistance value of the fourth resistor is greater than 2 megaohms, so that after the power connection unit is conducted, most of current flows to the power connection unit, and the connection between the ninth node and the power supply end is equivalent to disconnection.

In a second aspect, an embodiment of the present application further provides a transformer system, which includes a magnetic core and the transformer circuit described in any one of the above, where the primary winding, the power supply winding, and the secondary winding are all disposed on the magnetic core.

The beneficial effect of this application does: the mode that the primary winding and the power supply winding are conducted in the same phase to supply power is adopted, so that the inductive voltage of the power supply winding is limited by the turn ratio between the power supply winding and the primary winding, the input voltage of the primary winding and the power supply voltage of the power supply winding are in a direct proportion relation, the range span of the power supply voltage of the power supply winding can be reduced, the voltage stress of corresponding elements in a circuit is reduced, and the possibility of overvoltage protection of a trigger circuit is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or technical solutions in related arts, the drawings used in the description of the embodiments or related arts will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic circuit diagram of a transformer circuit according to an embodiment of the present application;

FIG. 2 is a schematic circuit diagram of a power connection unit according to an embodiment of the present application;

FIG. 3 is a schematic circuit diagram of a transformer circuit according to another embodiment of the present application;

FIG. 4 is a schematic circuit diagram of a transformer circuit according to another embodiment of the present application;

fig. 5 is a schematic structural diagram of a magnetic core of a transformer system according to an embodiment of the present application.

Reference numerals:

11. a power management unit; 12. a power connection unit; 13. a power supply unit; 14. an output unit; 15. a rectifying unit; 16. a feedback unit; 21. a magnetic core; l1, primary winding; l2, supply winding; l3, secondary winding; g1, first node; g2, a second node; g3, third node; g4, fourth node; g5, fifth node; g6, sixth node; g7, seventh node; g8, eighth node; g9, ninth node; q1, a first switch tube; q2, second switch tube; c1, a first capacitance; c2, a second capacitor; c3, a filter capacitor; r1, a first resistor; r2, a second resistor; r3, third resistor;

r4, fourth resistor; d1, a first diode; d2, a second diode; VCC, a power supply terminal; VIN, power supply voltage terminal; VOUT, voltage output terminal; OC, photoelectric coupler; TL431 and a voltage stabilizer.

Detailed Description

In order to more clearly illustrate the embodiments of the present application or technical solutions in the related art, the following description will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.

In the conventional flyback transformer, the auxiliary power supply winding is generally switched on or off simultaneously with the secondary output winding, the power supply voltage of the auxiliary winding is in a direct proportion to the output voltage of the secondary winding, and the range of the conventional output voltage is greatly expanded, so that the voltage range of the auxiliary power supply winding in the same phase with the secondary output winding is also enlarged. This supply mode, at a wide output voltage, may cause the voltage range of the auxiliary supply winding to become large, increase the voltage stress of the corresponding components in the transformer supply circuit, possibly cause damage to the corresponding components in the transformer supply circuit, and possibly trigger an overvoltage protection in the circuit.

In order to solve the above technical problem, embodiments of the present application provide a transformer circuit and a transformer system, so as to reduce a voltage range span of a power supply winding, reduce voltage stress of corresponding elements in the circuit, and reduce a possibility of overvoltage protection of a trigger circuit.

In a first aspect, an embodiment of the present application provides a transformer circuit, and referring to fig. 1, the transformer circuit includes a power management unit 11, a power connection unit 12, a power supply unit 13, and an output unit 14.

The power connection unit 12 includes a primary winding L1 and a first switching tube Q1, a first end of the primary winding L1 is used for connecting a power supply voltage, a second end of the primary winding L1 is electrically connected to a first end of the first switching tube Q1, and a control end of the first switching tube Q1 is electrically connected to the power management unit 11 element 111. The first end of the primary winding L1 is connected to a supply voltage end VIN, the supply voltage may provide electric energy for the primary winding L1, and the supply voltage may be provided by a battery or a power supply socket.

The power supply unit 13 has a power supply terminal VCC, the power supply terminal VCC with the power management unit 11 unit 111 is electrically connected to supply power to the power management unit 11, the power supply unit 13 includes a power supply winding L2. The output unit 14 includes a secondary winding L3. The primary winding L1 and the power supply winding L2 are wound in the same direction. The output unit 14 has a voltage output terminal VOUT for outputting a voltage

It should be noted that the winding directions of the primary winding L1 and the power supply winding L2 are the same, and the winding directions of the primary winding L1 and the secondary winding L3 are opposite, for example, the same-name ends of the primary winding L1, the power supply winding L2, and the secondary winding L3 marked in fig. 1 are the same-name ends, which are indicated that under the action of the same alternating magnetic flux, ends having the same potential polarity in two or more windings at any time are the same-name ends, so that the primary winding L1 and the power supply winding L2 are in the same phase, and the primary winding L1 and the secondary winding L3 are in the opposite phase. In fig. 1, for convenience of illustration, the primary winding L1, the power supply winding L2, and the secondary winding L3 are shown separately, and in actual practice, the primary winding L1, the power supply winding L2, and the secondary winding L3 are integrated.

In the related art, the power management unit 11 supplies power from the induced voltage of the power winding L2, the power winding L2 is in phase with the secondary winding L3, the induced voltage of the power winding L2 is limited by the turn ratio between the power winding L2 and the secondary winding L3, and the power supply voltage of the power winding L2 is in direct proportion to the output voltage of the secondary winding L3. When the output voltage VOUT of the voltage output terminal of the transformer circuit is higher, the induced voltage on the power supply winding L2 will also be higher correspondingly; when the output voltage VOUT of the voltage output terminal of the transformer circuit is low, the induced voltage on the supply winding L2 also becomes low. In this power supply mode, in the case of a wide output voltage, the power supply voltage range of the power supply winding L2 spans too large, which increases the voltage stress of the corresponding components in the circuit and may also trigger overvoltage protection in the circuit.

In the embodiment of the present application, a mode of supplying power by conducting the primary winding L1 and the power supply winding L2 in the same phase is adopted, so that the induced voltage of the power supply winding L2 is limited by the turns ratio between the power supply winding L2 and the primary winding L1, and the input voltage of the primary winding L1 is in a direct proportion to the power supply voltage of the power supply winding L2. Because the range of the input voltage of the power grid is much smaller than the range span of the output voltage of the secondary winding L3 in the related art, the range span of the supply voltage of the supply winding L2 can be reduced, the voltage stress of corresponding elements in the circuit can be reduced, and the possibility of triggering the overvoltage protection of the circuit can be reduced by adopting the method that the primary winding L1 and the supply winding L2 are conducted in the same phase.

It should be further noted that the primary winding L1 is electrically connected to the power management unit 11 through the first switching tube Q1, as shown in fig. 1, the first switching tube Q1 may be a triode, which is exemplified by a triode as an NPN-type triode, at this time, a base of the triode is electrically connected to the power management unit 11, a collector of the triode is electrically connected to the second end of the primary winding L1, and an emitter of the triode is grounded. After the power management unit 11 enters a normal working process, the power management unit 11 outputs a high level signal to turn on the first switching tube Q1, so that the primary winding L1 enters an energy storage stage, and at this time, the power supply winding L2 is simultaneously turned on and generates an induced voltage to store energy. Of course, as shown in fig. 1 and fig. 2, the first switching tube Q1 may also be a field effect tube, and the field effect tube is an NMOS tube for example, in this case, the gate of the field effect tube is electrically connected to the power management unit 11, the drain of the field effect tube is electrically connected to the second end of the primary winding L1, and the source of the field effect tube is grounded.

It should be noted that, after the first switch tube Q1 is turned off, the power connection unit 12 is turned off, and the circuit enters a flyback stage, where the flyback stage specifically means that when the first switch tube Q1 is turned on, the power connection unit 12 is turned on, and the secondary winding L3 serves as an inductor, electric energy is converted into magnetic energy, and at this time, no current flows in the loop in the output unit 14; on the contrary, when the first switching tube Q1 is turned off, the power unit 12 is turned off, the secondary winding L3 releases energy, the magnetic energy is converted into electric energy, and there is current in the loop of the output unit 14.

In some embodiments of the present application, referring to fig. 1, the power supply unit 13 further includes a first capacitor C1, a first plate of the first capacitor C1 and a first end of the power supply winding L2 are electrically connected to a first node G1, and the first node G1 is electrically connected to the power management unit 11; the second plate of the first capacitor C1 and the second end of the power supply winding L2 are electrically connected to a second node G2, and the second node G2 is grounded.

It should be noted that, when the primary winding L1 and the power supply winding L2 are conducted in the same phase, the power supply winding L2 generates an induced voltage, and the power supply winding L2 can charge the first capacitor C1. When the first switch Q1 is turned off, the first capacitor C1 in the power supply unit 13 can supply power to the power management unit 11, so that the power management unit 11 can operate normally. The type and type of the first capacitor C1 can be selected according to actual needs, and the application is not particularly limited.

Further, in some embodiments of the present application, with reference to fig. 1, the power supply unit 13 further includes a first diode D1 connected in series between the power supply winding L2 and the first node G1, the positive electrode of the first diode D1 and the first end of the power supply winding L2 are electrically connected to the third node G3, and the negative electrode of the first diode D1 is electrically connected to the first node G1.

It is known to those skilled in the art that a diode has a unidirectional turn-on behavior, i.e., when a forward bias voltage is applied to the diode, the diode turns on, and when a reverse bias voltage is applied to the diode, the diode turns off. In the embodiment of the present application, the first diode D1 is utilized to ensure that the current is unidirectionally conducted from the third node G3 to the first node G1 after the power supply winding L2 generates the induced voltage, so that the current is prevented from being reversely sunk from the first node G1 to the third node G3 after the first capacitor C1 is connected to the voltage. The type and type of the first diode D1 can be selected according to actual needs, and the application is not particularly limited.

With continued reference to fig. 1, in some embodiments of the present application, the power supply unit 13 further includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 is electrically connected to the third node G3, a second end of the first resistor R1 and a first end of the second resistor R2 are electrically connected to a fourth node G4, the fourth node G4 is electrically connected to the power management unit 11, and a second end of the second resistor R2 is electrically connected to the second node G2.

It should be noted that the first resistor R1 and the second resistor R2 may receive the voltage across the power supply winding L2, and provide the detection signal to the power management unit 11 based on the voltage across the power supply winding L2. When the power management unit 11 detects that the voltage of the first resistor R1 and the second resistor R2 drops to a certain value, which is not enough for the power management unit 11 to generate a signal for controlling the circuit switch, the circuit is suspended. The resistance values of the first resistor R1 and the second resistor R2 can be selected according to actual requirements, and the types and types of the first resistor R1 and the second resistor R2 can also be selected according to actual requirements, which is not specifically limited in the present application.

In some embodiments, referring to fig. 1, the power connection unit 12 further includes a third resistor R3, a first end of the third resistor R3 and a second end of the first switch Q1 are electrically connected to a fifth node G5, a second end of the second resistor R2 is grounded, and the fifth node G5 is electrically connected to the power management unit 11.

It should be noted that, when the power management unit 11 outputs a high level signal to the first switching tube Q1, so that the first switching tube Q1 is turned on, the first end of the primary winding L1 is electrically connected to the power voltage end VIN to access the power voltage, the primary winding L1 stores energy, and when the power management unit 11 detects that the voltage value of the third resistor R3 is greater than or equal to the preset voltage, the power management unit 11 outputs a low level signal to the first switching tube Q1, so that the first switching tube Q1 is turned off, and the circuit enters the flyback stage. The resistance value of the third resistor R3 can be selected according to actual requirements, and the type and style of the third resistor R3 can also be selected according to actual requirements, which is not specifically limited in the present application.

In some embodiments of the present application, with continued reference to fig. 1, the output unit 14 further includes a second diode D2, an anode of the second diode D2 is electrically connected to the first end of the secondary winding L3, a cathode of the second diode D2 is electrically connected to the second end of the secondary winding L3 at a seventh node G7, and the seventh node G7 is grounded.

It should be noted that, when the first switching tube Q1 is turned on, the electrical connection unit 12 is turned on, the current on the primary winding L1 flows from the first end of the primary winding L1 to the second end of the primary winding L1, and since the winding directions of the primary winding L1 and the secondary winding L3 are opposite and have opposite phases, at this time, the current on the secondary winding L3 flows from the cathode of the second diode D2 to the anode, the second diode D2 is turned off due to reverse bias, and the output unit 14 is turned off. When the first switching tube Q1 is turned off, as can be seen from lenz's law (e ═ N Δ Φ/. DELTA.t), the primary winding L1 generates a reverse potential, and then the current of the secondary winding L3 flows from the anode of the second diode D2 to the cathode, and the second diode D2 of the output unit 14 is turned on in the forward direction, so that the output unit 14 is turned on. The type and style of the second diode D2 can be selected according to actual needs, and the application is not particularly limited.

Of course, the above-mentioned function of turning off or turning on the output unit 14 may also be realized by other elements, referring to fig. 3, the output unit 14 may further include a second switching tube Q2, a control end of the second switching tube Q2 is electrically connected to the power management unit 11, a first end of the second switching tube Q2 is electrically connected to a second end of the secondary winding L3, a second end of the second switching tube Q2 and a first end of the secondary winding L3 are electrically connected to a sixth node G6, and the sixth node G6 is grounded.

As known to those skilled in the art, the switching tube works in the cut-off region and the saturation region, the switching tube in the cut-off region is equivalent to a cut-off circuit, and the switching tube in the saturation region is equivalent to a turn-on circuit, so that the switching tube has the function of completing the turn-off and turn-on of the circuit. In this embodiment, when the first switch tube Q1 is turned on and the power connection unit 12 is turned on, the power management unit 11 sends a low-level voltage signal to the control end of the second switch tube Q2, so that the voltage at the control end of the second switch tube Q2 is smaller than the starting voltage of the second switch tube Q2, the second switch tube Q2 is in the cut-off region, and the output unit 14 is in the off state; when the first switch tube Q1 is turned off, the power management unit 11 sends a high-level voltage signal to the control terminal of the second switch tube Q2, so that the voltage at the control terminal of the second switch tube Q2 is greater than or equal to the starting voltage of the second switch tube Q2, the second switch tube Q2 is in a saturation region, and the output unit 14 is in a conducting state.

As shown in fig. 3, the second switching tube Q2 may be a triode, and the triode is an NPN-type triode for example, in which case, a base of the triode is electrically connected to the power management unit 11, a collector of the triode is electrically connected to the second end of the secondary winding L3, and an emitter of the triode Z is electrically connected to the first end of the secondary winding L3. When the first switching tube Q1 is turned on, the power management unit 11 sends a low-level voltage signal to the base of the triode, so that the voltage of the base is smaller than the turn-on voltage of the triode, at this time, the triode is in the cut-off region, and the output unit 14 is in the off state; when the first switch Q1 is turned off, the power management unit 11 sends a high level voltage signal to the base of the transistor, so that the voltage at the base is greater than or equal to the turn-on voltage of the transistor, and at this time, the output unit 14 is in a conducting state.

Of course, the second switching tube Q2 may also be a field effect tube, and the field effect tube is an NMOS tube for example, in this case, the gate of the field effect tube is electrically connected to the power management unit 11, the drain of the field effect tube is electrically connected to the second end of the secondary winding L3, the source of the field effect tube is electrically connected to the sixth node G6 and the first end of the secondary winding L3, and the sixth node G6 is grounded. When the first switching tube Q1 is turned on, the power management unit 11 sends a low-level voltage signal to the gate of the fet, so that the voltage between the gate and the source is smaller than the cut-off voltage of the fet, at this time, all the conductive channels in the fet are pinched off, the fet is in the cut-off region, and the output unit 14 is in the off state; when the first switching transistor Q1 is turned off, the power management unit 11 sends a high level voltage signal to the gate of the fet so that the voltage between the gate and the source is greater than or equal to the off-voltage of the fet, and at this time, the output unit 14 is in the on state.

Further, in some embodiments of the present application, with continued reference to fig. 3, the output unit 14 further includes a second capacitor C2, when the output unit 14 includes the second switching tube Q2, a first plate of the second capacitor C2 is electrically connected to the first end of the secondary winding L3, and a second plate of the second capacitor C2 is electrically connected to the sixth node G6; when the output unit 14 includes the second diode D2, the first plate of the second capacitor C2 and the negative electrode of the second diode D2 are electrically connected to the eighth node G8, and the second plate of the second capacitor C2 and the seventh node G7 are electrically connected.

It should be noted that the second capacitor C2 may be used to filter out ac components, to make the output dc smoother, and to output a voltage to the load. Because the voltage output end VOUT outputs the oscillating square wave signal, an output circuit needs to filter out alternating current components, and the output voltage is direct current voltage. Since the filtering requires a large capacitance of the energy storage capacitor, the second capacitor C2 may be an electrolytic capacitor, and certainly, the second capacitor C2 may also be another capacitor type with a large capacity, which is not limited in this application.

Still further, in some embodiments of the present application, referring to fig. 3 and 4, the output unit 14 further includes a feedback unit 16, when the output unit 14 includes the second switch Q2, an input terminal of the feedback unit 16 is electrically connected to a control terminal of the second switch Q2, and an output terminal of the feedback unit 16 is electrically connected to the power management unit 11; when the output unit 14 includes the second diode D2, the input terminal of the feedback unit 16 is electrically connected to the eighth node G8, and the output terminal of the feedback unit 16 is electrically connected to the power management unit 11.

It should be noted that the power management unit 11 detects the voltage signal in the output unit 14 via the feedback unit 16, so as to control the on/off of the first switch tube Q1. As shown in fig. 3, the feedback unit 16 may include a photo coupler OC, when an input end of the photo coupler OC inputs an electrical signal, a light emitter in the photo coupler OC emits light, and a light receiver receives the light and then generates a photocurrent which flows out from an output end of the photo coupler OC to the power management unit 11, and the power management unit 11 may detect a voltage signal of the output unit 14 via the photo coupler OC. The feedback unit 16 may further include a voltage regulator TL431, the voltage signal of the output unit 14 is transmitted to the power management unit 11 through a feedback loop of the voltage regulator TL431, and the power management unit 11 controls the on/off of the first switch tube Q1 according to the detected voltage signal of the output unit 14. The specific working principle of the voltage regulator TL431 has been disclosed in the related art, and is not described herein.

It should be further noted that, as shown in fig. 3, when the output unit 14 includes the second switching tube Q2, the secondary winding L3 charges the second capacitor C2 through the second switching tube Q2, and when the voltage of the second capacitor C2 reaches a preset value, the power management unit 11 may detect the signal transmitted by the feedback unit 16 and send a high-level signal to the first switching tube Q1, so that the first switching tube Q1 is turned on, and at this time, the power connection unit 12 is turned on, and the output unit 14 is turned off. As shown in fig. 4, when the output unit 14 includes the second diode D2, the secondary winding L3 charges the second capacitor C2 via the second diode D2, and since the voltage across the second capacitor C2 cannot be abruptly changed, the potential of the eighth node G8 increases as the voltage across the second capacitor C2 increases with time. If the potential of the eighth node G8 is higher than the potential of the first end of the secondary winding L3, the on condition of the second diode D2 cannot be satisfied, and the second diode D2 is turned off. Therefore, when the potential of the eighth node G8 is equal to the potential of the first end of the secondary winding L3, the power management unit 11 detects the signal transmitted by the feedback unit 16 and sends a high-level signal to the first switch tube Q1, so that the first switch tube Q1 is turned on, and at this time, the power connection unit 12 is turned on, and the output unit 14 is turned off.

After the power connection unit 12 is turned on, the primary winding L1 enters an energy storage stage, and the power supply winding L2 is simultaneously turned on and generates an induced voltage to store energy, at this time, the current of the secondary winding L3 flows from the cathode of the second diode D2 to the anode direction, the second diode D2 of the output unit 14 is reversely biased and turned off, the output unit 14 is turned off, and the second capacitor C2 outputs a voltage to the load.

In some embodiments of the present application, referring to fig. 4, the transformer circuit further includes a fourth resistor R4, the fourth resistor R4 is connected in series between the ninth node G9 and the power supply terminal VCC, and a resistance of the fourth resistor R4 is greater than 2 megaohms.

It should be noted that, at the initial stage of starting, the power management unit 11 needs to input a first starting voltage, so that the power management unit 11 drives the first switching tube Q1 to conduct, the input voltage may be charged to the first capacitor C1 through the fourth resistor R4, the input voltage may also input a starting voltage to the power management unit 11 through the fourth resistor R4, when the input voltage is greater than or equal to the starting voltage of the power management unit 11, the power management unit 11 starts and outputs a high level signal, and controls the first switching tube Q1 to conduct, then both the power connection unit 12 and the power supply unit 13 are conducted, and the primary winding L1 enters the energy storage stage.

It should be noted that, the resistance of the fourth resistor R4 is greater than 2 megaohms, so that after the power connection unit 12 is turned on, most of the current flows to the power connection unit 12, and the connection between the ninth node G9 and the power supply terminal VCC is equivalent to an open circuit. The type and style of the fourth resistor R4 can be selected according to actual needs, and the application is not particularly limited.

In addition, with continued reference to fig. 4, the transformer circuit may further include a rectifying unit 15, an input terminal of the rectifying unit 15 is used for connecting to a power voltage, and an output terminal of the rectifying unit 15 and the first terminal of the primary winding L1 are electrically connected to the ninth node G9.

It should be noted that the input end of the rectifying unit 15 is electrically connected to the power voltage end VIN to receive the power voltage, and the rectifying unit 15 converts the alternating voltage with positive and negative changes into a unidirectional pulsating voltage by using the unidirectional conductivity of the diode. Under the action of the ac power supply, the rectifier diode is periodically turned on and off, so that the output end of the rectifier unit 15 can output single-phase pulsating dc power. As shown in fig. 4, the rectifying unit 15 may include four or more rectifying diodes, and all the rectifying diodes are welded inside to form a bridge rectifying structure to perform a rectifying function. The rectifying unit 15 may further include a filter capacitor C3, and the filter capacitor C3 is installed at two ends of the bridge-type rectifying structure to reduce ac ripple factor and efficiently boost smooth dc output.

In a second aspect, the present embodiment provides a transformer system, which includes a magnetic core 21 and the transformer circuit described in any one of the above, where the primary winding L1, the power supply winding L2, and the secondary winding L3 are all disposed on the magnetic core 21. As shown in fig. 5, the primary winding L1 and the power supply winding L2 are wound in the same direction on the magnetic core 21, and the primary winding L1 and the secondary winding L3 are wound in opposite directions on the magnetic core 21. The induced voltage of the power supply winding L2 is controlled by the turns ratio between the power supply winding L2 and the primary winding L1, and the input voltage of the primary winding L1 is in direct proportion to the power supply voltage of the power supply winding L2. The transformer system may be a switching power supply or a socket.

In the embodiment of the present application, the complete working process of the transformer circuit is as follows:

in the initial stage of starting of the power management unit 11, the power source inputs a first starting voltage through the rectifying unit 15, the starting voltage can charge the first capacitor C1, when the voltage of the power supply terminal VCC reaches the starting voltage of the power management unit 11, the power management unit 11 starts and sends a high level signal to the first switching tube Q1, the first switching tube Q1 is controlled to be conducted, the power connection unit 12 is conducted, the primary winding L1 enters an energy storage stage, the power supply winding L2 generates an induction voltage, the power connection unit 12 and the power supply unit 13 are both conducted, and at this time, the power supply unit 13 charges the first capacitor C1. When the power management unit 11 detects that the voltage value of the third resistor R3 is greater than or equal to the preset voltage, the power management unit 11 outputs a low level signal to the first switch tube Q1, so that the first switch tube Q1 is turned off, the circuit enters a flyback stage, the first capacitor C1 provides a starting voltage for the power management unit 11, the voltage of the secondary winding L3 is reversed, the second diode D2/the second switch tube Q2 is turned on, the output unit 14 is turned on, the secondary winding L3 charges the second capacitor C2, when the voltage of the second capacitor C2 reaches a preset value, the feedback unit 16 transmits a voltage signal to the power management unit 11, the power management unit 11 detects the signal and sends a high level signal to the first switch tube Q1, the first switch tube Q1 is controlled to be turned on, and then the above steps are repeated.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A transformer circuit, comprising:

a power management unit;

the power connection unit comprises a primary winding and a first switching tube, wherein the first end of the primary winding is used for connecting a power supply voltage, the second end of the primary winding is electrically connected with the first end of the first switching tube, and the control end of the first switching tube is electrically connected with the power supply management unit;

the power supply unit is provided with a power supply end, the power supply end is electrically connected with the power supply management unit so as to supply power to the power supply management unit, and the power supply unit comprises a power supply winding;

an output unit for outputting a voltage, the output unit including a secondary winding;

and the winding directions of the primary winding and the power supply winding are the same.

2. The transformer circuit of claim 1, wherein the power supply unit further comprises:

a first pole plate of the first capacitor is electrically connected with a first end of the power supply winding to a first node, and the first node is electrically connected with the power supply management unit; the second pole plate of the first capacitor and the second end of the power supply winding are electrically connected to a second node, and the second node is grounded.

3. The transformer circuit of claim 2, wherein the power supply unit further comprises:

the first diode is connected between the power supply winding and the first node in series, the anode of the first diode is electrically connected with the first end of the power supply winding at the third node, and the cathode of the first diode is electrically connected with the first node.

4. The transformer circuit of claim 3, wherein the power supply unit further comprises:

the first end of the first resistor is electrically connected with the third node, the second end of the first resistor is electrically connected with the first end of the second resistor at a fourth node, the fourth node is electrically connected with the power management unit, and the second end of the second resistor is electrically connected with the second node.

5. The transformer circuit of claim 1, wherein the power connection unit further comprises:

a first end of the third resistor and a second end of the first switch tube are electrically connected to a fifth node, a second end of the third resistor is grounded, and the fifth node is electrically connected to the power management unit.

6. The transformer circuit of claim 1, wherein the output unit further comprises:

a control end of the second switching tube is electrically connected with the power management unit, a first end of the second switching tube is electrically connected with a second end of the secondary winding, the second end of the second switching tube and the first end of the secondary winding are electrically connected with a sixth node, and the sixth node is grounded;

or, an anode of the second diode is electrically connected to the first end of the secondary winding, a cathode of the second diode is electrically connected to a seventh node with the second end of the secondary winding, and the seventh node is grounded.

7. The transformer circuit of claim 6, wherein the output unit further comprises:

when the output unit comprises the second switching tube, a first polar plate of the second capacitor is electrically connected with the first end of the secondary winding, and a second polar plate of the second capacitor is electrically connected with the sixth node;

when the output unit comprises the second diode, the first plate of the second capacitor and the cathode of the second diode are electrically connected to an eighth node, and the second plate of the second capacitor is electrically connected to the seventh node.

8. The transformer circuit of claim 7, wherein the output unit further comprises:

when the output unit comprises the second switch tube, the input end of the feedback unit is electrically connected with the control end of the second switch tube, and the output end of the feedback unit is electrically connected with the power management unit;

when the output unit comprises the second diode, the input end of the feedback unit is electrically connected with the eighth node, and the output end of the feedback unit is electrically connected with the power management unit.

9. The transformer circuit of claim 1, further comprising:

and a first end of the fourth resistor and a first end of the primary winding are electrically connected to a ninth node, a second end of the fourth resistor is electrically connected to the power supply end, and the resistance value of the fourth resistor is greater than 2 megaohms.

10. A transformer system comprising a magnetic core and the transformer circuit of any one of claims 1 to 9, wherein the primary winding, the supply winding and the secondary winding are disposed on the magnetic core.

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