Load adjustment compensation circuit and charger

Abstract

The utility model provides a load adjustment compensation circuit and a charger, the load adjustment compensation circuit is coupled with a transformer, and the circuit comprises a gating branch circuit which is respectively coupled with a current detection pin of a control chip and a third end of a primary winding, is suitable for being gated or turned off in response to a driving signal, and is used for adjusting the current detection pin of the control chip and the third end of the primary winding when being in a gated state; gating a path between the third end of the primary winding and the first ground; the detection branch is respectively coupled with the current detection pin, the gating branch and the first end of the compensation winding, and is suitable for performing voltage division operation on the voltage on the path and outputting corresponding detection current to the current detection pin when the path is gated, and an equivalent voltage division resistance value on the detection branch is variable; and the control chip is used for outputting a driving signal with a duty ratio to the gating branch in response to the power supply voltage so as to gate the gating branch. By adopting the technical scheme, the implementation cost can be reduced under the condition that the current fluctuation is reduced.

Description

Technical Field

[0001] This utility model relates to the field of charging technology, and in particular to a load adjustment compensation circuit and charger. Background Technology

[0002] In recent years, with the popularization of electronic devices and the rapid development of technology, efficient, stable and adaptable charging solutions have become an important demand in the field of power electronics.

[0003] Currently, chargers are commonly used to charge electronic devices. In the actual charging process, the stability of charging parameters is crucial for the electronic devices.

[0004] However, current fluctuations often occur when charging electronic devices. Solutions developed to overcome these issues often increase circuit design complexity, extending development cycles and potentially raising production costs due to additional filtering components and complex control strategies. Utility Model Content

[0005] In view of this, the present invention provides a load adjustment compensation circuit and charger, which can reduce implementation costs while reducing current fluctuations.

[0006] This utility model provides a load adjustment and compensation circuit coupled to a transformer, wherein the transformer includes a primary winding, a secondary winding, and a compensation winding, and the load adjustment and compensation circuit includes a control chip, a selection branch, and a detection branch;

[0007] The selected branch is coupled to the current detection pin of the control chip and the third terminal of the primary winding, respectively, and is adapted to be selected or turned off in response to the drive signal. When it is in the selected state, it selects the path between the third terminal of the primary winding and the first ground.

[0008] The detection branch is coupled to the current detection pin, the selection branch and the first end of the compensation winding, respectively. It is adapted to perform a voltage divider operation on the voltage of the path when the path is selected, and output the corresponding detection current to the current detection pin. The equivalent voltage divider resistance value of the detection branch is variable.

[0009] The control chip is configured to respond to the supply voltage by outputting a drive signal with a duty cycle to the selected branch to select the selected branch, and to adjust the duty cycle of the drive signal according to the detected current and a preset current to change the current at the first end of the compensation winding.

[0010] Optionally, the detection branch includes a first detection module and a second detection module, wherein the first detection module is coupled to the second detection module, the current detection pin and the first end of the compensation winding respectively, and has a first equivalent resistance; the second detection module is coupled to the selection branch and connected to a first ground, and has a second equivalent resistance.

[0011] When the selected branch is selected, a voltage divider operation is performed through the first equivalent resistor and the second equivalent resistor to obtain the detection current, wherein the first equivalent resistor and / or the second equivalent resistor is variable.

[0012] Optionally, the load adjustment compensation circuit satisfies at least one or more of the following:

[0013] The first detection module includes: a first detection resistor, a first diode, and a second detection resistor, wherein the first end of the first detection resistor is coupled to the second detection module and the current detection pin, and the second end of the first detection resistor is coupled to the first end of the first diode; the second end of the first diode is coupled to the first end of the compensation winding through the second detection resistor.

[0014] The second detection module includes: a third detection resistor, a fourth detection resistor, a fifth detection resistor, a sixth detection resistor, and a seventh detection resistor, wherein the first end of the third detection resistor is coupled to the current detection pin and the first detection module, respectively; the second end of the third detection resistor is coupled to the first ends of the fourth, fifth, sixth, and seventh detection resistors, respectively, and the selection branch; the second ends of the fourth, fifth, sixth, and seventh detection resistors are connected to a first ground.

[0015] The selection branch includes a selection transistor, the first end of which is coupled to the third end of the primary winding, and the second end of which is coupled to the current detection pin through the detection branch and connected to a first ground.

[0016] It also includes: a voltage divider branch, coupled to the voltage detection pin of the control chip and the first end of the compensation winding, for detecting the voltage at the first end of the compensation winding to obtain a feedback voltage; including: a first voltage divider resistor, a second voltage divider resistor and a third voltage divider resistor, wherein the first end of the first voltage divider resistor is coupled to the voltage detection pin and the first end of the second voltage divider resistor respectively, and the second end of the first voltage divider resistor is connected to a first ground; the second end of the second voltage divider resistor is coupled to the first end of the compensation winding through the third voltage divider resistor.

[0017] Optionally, the control chip further includes:

[0018] A compensation pin, which is connected to the first ground in sequence through a compensation resistor and a compensation capacitor;

[0019] A grounding pin is connected to the first end of the compensation winding via a grounding capacitor and to a first ground.

[0020] The unused pin is coupled to the power supply pin of the control chip.

[0021] Optionally, the load adjustment and compensation circuit further includes at least one or more of the following: a buffer branch, coupled to the power supply pin of the control chip, adapted to step down the power supply voltage to generate a drive voltage;

[0022] The discharge branch includes: a first discharge module and a second discharge module. The first discharge module is disposed between the control terminal of the gating transistor and the drive pin of the control chip, and the second discharge module is disposed between the control terminal of the gating transistor and the current detection pin. It is adapted to feed back the junction capacitance voltage to the drive pin and the current detection pin respectively when the gating transistor is turned off.

[0023] The freewheeling branch is coupled to the first end of the compensation winding and the ground pin of the control chip, respectively, and is adapted to provide a freewheeling path when the gating transistor is turned off.

[0024] Optionally, the first discharge module includes: a second diode and a first discharge resistor, wherein the first end of the second diode is coupled to the control terminal of the selection transistor, and the second end of the third diode is coupled to the drive pin through the first discharge resistor;

[0025] The second discharge module includes: a second discharge resistor;

[0026] The buffer branch includes: a first buffer resistor and a second buffer resistor, wherein a first end of the first buffer resistor is adapted to receive the power supply voltage, and a second end of the first buffer resistor is coupled to the power supply pin through the second buffer resistor;

[0027] The freewheeling branch includes: a third diode, a freewheeling resistor, a first freewheeling capacitor, and a second freewheeling capacitor. The first end of the freewheeling resistor is coupled to the first end of the compensation winding. The second end of the freewheeling resistor is connected to a first ground through the third diode and the first freewheeling capacitor, and is also connected to a first ground through the third diode and the second freewheeling capacitor.

[0028] Optionally, the primary winding and the compensation winding are located on the same side, and the third end of the primary winding and the first end of the secondary winding are of the same name, and the first end of the secondary winding and the first end of the compensation winding are of the same name.

[0029] Optionally, the load adjustment and compensation circuit further includes an output branch coupled to the secondary winding for rectifying and filtering the output voltage on the secondary winding.

[0030] Optionally, the output branch includes a rectifier module and a filter module, wherein: the rectifier module includes a switching chip, a first rectifier resistor, a second rectifier resistor, and a rectifier capacitor, wherein: the first terminal of the switching chip is coupled to the first terminal of the secondary winding, the second rectifier resistor, and the first terminal of the first rectifier resistor, respectively; the second terminal of the switching chip is coupled to the second terminal of the second rectifier resistor and the second terminal of the first rectifier resistor through the rectifier capacitor, and is also coupled to the filter module and connected to a second ground;

[0031] The filtering module includes: a first filtering capacitor, a second filtering capacitor, a third filtering capacitor, a fourth filtering capacitor, and a filtering resistor connected in parallel, and a common-mode inductor coupled to the fourth filtering capacitor and connected in parallel to a second ground.

[0032] Accordingly, the present invention also provides a charger, including: the load adjustment compensation circuit described in any of the foregoing embodiments.

[0033] Compared with the prior art, the technical solution of this utility model embodiment has the following advantages:

[0034] The load adjustment compensation circuit provided in this embodiment of the invention allows the detection branch to perform voltage division on the selected path when the selected branch is activated. Since the detection branch is coupled to the first end of the compensation winding, the current change in the detection branch can refer to the current change at the first end of the compensation winding. Thus, when the current detection pin detects the detected current, the control chip can adjust the duty cycle of the drive signal in real time based on the detected current and a preset current, thereby changing the conduction time of the selected branch and consequently changing the current at the first end of the compensation winding, thereby reducing current fluctuations. Furthermore, the load adjustment compensation circuit can be implemented using conventional components, thus reducing implementation costs. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0036] Figure 1 This diagram shows a structural schematic of a load adjustment and compensation circuit according to an embodiment of the present invention.

[0037] Figure 2 A schematic diagram of the specific structure of a load adjustment and compensation circuit according to an embodiment of the present invention is shown. Detailed Implementation

[0038] As described in the background section, in practical applications, situations may arise where the output voltage is high but the output current is low, or vice versa. This will affect the charging stability of electronic devices.

[0039] To address the aforementioned technical problems, this utility model provides a load adjustment and compensation circuit. When the selected branch is activated, the detection branch performs a voltage divider operation on the path. Furthermore, the detection branch is coupled to the first end of the compensation winding. Therefore, the current change in the detection branch refers to the current change at the first end of the compensation winding. Thus, when the current detection pin detects the detected current, the control chip can adjust the duty cycle of the drive signal in real time based on the detected current and a preset current, thereby changing the conduction time of the selected branch and consequently altering the current at the first end of the compensation winding, thereby reducing current fluctuations. Moreover, the load adjustment and compensation circuit can be implemented using conventional components, thus reducing implementation costs.

[0040] To enable those skilled in the art to better understand and implement this disclosure, the following detailed description of the specific solutions, principles, advantages, and effects of this disclosure is provided with reference to the accompanying drawings and specific embodiments.

[0041] See Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a load adjustment and compensation circuit according to one embodiment of the present invention. Figure 2 This is a schematic diagram of the specific structure of a load adjustment and compensation circuit in one embodiment of the present invention.

[0042] like Figure 1 and Figure 2 As shown, the load adjustment and compensation circuit can be coupled to a transformer T, which may include a primary winding Wp, a secondary winding Ws, and a compensation winding Wc.

[0043] In this embodiment, the primary winding Wp and the compensation winding Wc are located on the same side, and the third end 3 of the primary winding Wp and the first end 4 of the secondary winding Ws are the same end, and the first end 4 of Ws and the first end 6 of the compensation winding Wc are the same end.

[0044] In some embodiments, the number of turns in the primary winding Wp is greater than the number of turns in the compensation winding Wc, thereby enabling a step-down operation.

[0045] More specifically, a change in the voltage across any one of the primary winding Wp, secondary winding Ws, and compensation winding Wc will cause changes in the voltage and / or current across the other coils. This voltage and / or current change will act on the detection branch 120, which in turn can change the drive signal output by the control chip 130, thereby changing the conduction duration of the selection branch 110.

[0046] Accordingly, the load adjustment and compensation circuit includes: a control chip 130, a gating branch 110, and a detection branch 120, wherein:

[0047] The selection branch 110 is coupled to the current detection pin ISEN of the control chip 130 and the third terminal 3 of the primary winding Wp, respectively. It is adapted to be selected or turned off in response to a drive signal, and when it is in the selected state, it selects the path between the third terminal 3 of the primary winding Wp and the first ground GND1.

[0048] Specifically, when the selected branch 110 is turned on, the path between the third terminal 3 of the primary winding Wp and the first ground GND1 is turned on, and the first terminal 1 and the third terminal 3 of the primary winding Wp form a voltage with the upper positive and the lower negative. Therefore, when the selected branch 110 is turned on, the voltage on the path will increase as the conduction time increases, thereby changing the value of the detection current.

[0049] The detection branch 120 is coupled to the current detection pin ISEN, the selection branch 110 and the first terminal 6 of the compensation winding Wc, respectively. It is adapted to perform voltage division operation on the path when the path is selected, and output the corresponding detection current to the current detection pin ISEN.

[0050] Specifically, when the selected branch 110 is selected, the detection branch 120 can divide the voltage caused by the selected branch 110, thereby generating a corresponding detection current.

[0051] Furthermore, the equivalent voltage divider resistance value on the detection branch is variable, thus allowing the detection current to be altered.

[0052] The control chip 130 is used to respond to the power supply voltage V1, output a drive signal with a duty cycle to the selection branch 110 to select the selection branch 110, and adjust the duty cycle of the drive signal according to the detected current and the preset current to change the current at the first terminal 6 of the compensation winding Wc.

[0053] Specifically, when the supply voltage V1 is received, the control chip 130 can generate a corresponding drive signal to the selection branch 110, which can then be selected. Based on the transformer T's own voltage transformation characteristics, voltage changes can be made, thus forming a drive-feedback closed loop, which can reduce current fluctuations. Furthermore, the load adjustment and compensation circuit can be implemented using conventional components, thereby reducing implementation costs.

[0054] In this embodiment, see Figure 1 and Figure 2 The detection branch 120 includes a first detection module 122 and a second detection module 124. The first detection module 122 is coupled to the second detection module 124, the current detection pin ISEN, and the first end of the compensation winding Wc, and has a first equivalent resistance. The second detection module 124 is coupled to the selection branch 110 and connected to a first ground, and has a second equivalent resistance.

[0055] When the selected branch 110 is selected, a voltage divider operation is performed through the first equivalent resistor and the second equivalent resistor to obtain the detection current, wherein the first equivalent resistor and / or the second equivalent resistor is variable.

[0056] Specifically, the current detection pin ISEN is coupled to the first end of the compensation winding Wc through the first detection module 122, and is coupled to the third end 3 of the primary winding Wp through the second detection module 124. Therefore, the current detection pin ISEN can detect the detection current used to reflect the change in the current at the first end of the compensation winding Wc.

[0057] Furthermore, by pre-setting the first and second equivalent resistances, the detection current can be detected in real time.

[0058] Furthermore, the first equivalent resistance and / or the second equivalent resistance can be variable, thus changing the detection current so that it matches the preset current.

[0059] In this embodiment, the first detection module 122 may include: a first detection resistor R1, a first diode D1, and a second detection resistor R2, wherein the first end of the first detection resistor R1 is coupled to the second detection module 124 and the current detection pin ISEN, respectively, and the second end of the first detection resistor R1 is coupled to the first end of the first diode D1; the second end of the first diode D1 is coupled to the first end 6 of the compensation winding Wc through the second detection resistor R2.

[0060] Specifically, the first sensing resistor R1 and the second sensing resistor R2 form the first equivalent resistance. Furthermore, by setting the first diode D1, current can only flow from the first sensing resistor R1 to the second sensing resistor R2.

[0061] The second detection module 124 may include: a third detection resistor R3, a fourth detection resistor R4, a fifth detection resistor R5, a sixth detection resistor R6, and a seventh detection resistor R7. The first end of the third detection resistor R3 is coupled to the current detection pin ISEN and the first detection module 122, respectively. The second end of the third detection resistor R3 is coupled to the first ends of the fourth detection resistor R4, the fifth detection resistor R5, the sixth detection resistor R6, and the seventh detection resistor R7, as well as the selection branch 110. The second ends of the fourth detection resistor R4, the fifth detection resistor R5, the sixth detection resistor R6, and the seventh detection resistor R7 are connected to the first ground GND1.

[0062] Specifically, the third detection resistor R3, the fourth detection resistor R4, the fifth detection resistor R5, the sixth detection resistor R6, and the seventh detection resistor R7 form the second equivalent resistance.

[0063] The selection branch 110 may include: a selection transistor Q1, the first end of which is coupled to the third end 3 of the primary winding Wp, and the second end is coupled to the current detection pin ISEN through the detection branch 120 (e.g., the second detection module 124) and connected to the first ground GND1.

[0064] See next Figure 2 The load adjustment and compensation circuit also includes a voltage divider branch, which is coupled to the voltage detection pin ISEN of the control chip and the first terminal 6 of the compensation winding Wc, for detecting the voltage at the first terminal 6 of the compensation winding Wc and obtaining the feedback voltage.

[0065] Specifically, when the feedback voltage is detected to be lower than the reference voltage, the on-time of the selector transistor Q1 can be adjusted to increase the output voltage or current; conversely, the on-time can be adjusted to increase the output voltage or current.

[0066] Accordingly, the voltage divider branch may include: a first voltage divider resistor R8, a second voltage divider resistor R9, and a third voltage divider resistor R10, wherein the first end of the first voltage divider resistor R8 is coupled to the voltage detection pin VSEN and the first end of the second voltage divider resistor R9, respectively, and the second end of the first voltage divider resistor R8 is connected to the first ground GND1; the second end of the second voltage divider resistor R9 is coupled to the first end 6 of the compensation winding Wc through the third voltage divider resistor R10.

[0067] Specifically, the feedback voltage detected by the voltage divider branch is the voltage drop across the first voltage divider resistor R8.

[0068] In this embodiment, the control chip 130 may further include:

[0069] The compensation pin COMP is connected to the first ground GND1 via the compensation resistor R11 and the compensation capacitor C2 in sequence.

[0070] Stable compensation is achieved by setting compensation capacitor C2 and compensation resistor R11.

[0071] The grounding pin GND is coupled to the first terminal 6 of the compensation winding Wc through the grounding capacitor C3, and connected to the first ground GND1.

[0072] The idle pin NC is coupled to the power supply pin VIN of the control chip 130.

[0073] In practical applications, the power supply voltage V1 is generally 310V, while the operating voltage of the control chip 130 is generally lower.

[0074] Based on this, see next. Figure 1 The load adjustment and compensation circuit may further include: a buffer branch 140, which is coupled to the power supply pin VIN of the control chip 130 and is adapted to step down the power supply voltage V1 to generate a drive voltage.

[0075] In some embodiments, see Figure 2 The buffer branch 140 may include: a first buffer resistor R12 and a second buffer resistor R13, wherein the first end of the first buffer resistor R12 is adapted to the input power supply voltage, and the second end of the first buffer resistor R12 is coupled to the power supply pin VIN through the second buffer resistor R13.

[0076] By setting the first buffer resistor R12 and the second buffer resistor R13, a suitable driving voltage can be provided to the control chip 130, thus ensuring the safe and stable operation of the control chip 130.

[0077] In some embodiments, the second buffer resistor R13 is also coupled to the first terminal 6 of the compensation winding Wc.

[0078] As can be seen from the foregoing, this solution achieves the effect of reducing current fluctuations by selectively switching transistor Q1 on and off.

[0079] In practical work, the inventors discovered that at the moment when the turn-on transistor Q1 is turned off, the turn-on transistor Q1 is equivalent to a capacitor, and the spike voltage discharged in the turn-on transistor Q1 will damage the circuit and reduce performance.

[0080] Based on this, see next. Figure 2The load adjustment compensation circuit may further include: an absorption branch 150, which is coupled to the first terminal of the selection transistor Q1 and the third terminal 3 of the primary winding Wp, respectively, and is adapted to absorb the spike voltage generated by the selection transistor Q1 at the instant when the selection transistor Q1 is turned off.

[0081] In one embodiment, see Figure 2 The absorption branch 150 may include: a fourth diode D2, a first absorption capacitor C4, a first absorption resistor R14, a second absorption resistor R15, a third absorption resistor R16, and a fourth absorption resistor R17, wherein: the first terminal of the fourth diode D2 is coupled to the first terminal of the select transistor Q1 and the third terminal 3 of the primary winding Wp, respectively; the second terminal of the fourth diode D2 is coupled to the first terminals of the first absorption capacitor C4, the first absorption resistor R14, the second absorption resistor R15, the third absorption resistor R16, and the fourth absorption resistor R17; and the second terminals of the first absorption capacitor C4, the first absorption resistor R14, the second absorption resistor R15, the third absorption resistor R16, and the fourth absorption resistor R17 are adapted to receive the supply voltage V1.

[0082] In other words, the absorption branch 150 is an RCD absorption circuit. Furthermore, by employing the fourth diode D2, the flow direction of the peak voltage is ensured to be solely from the fourth diode D2 to the first absorption resistor R3, which significantly improves the operational stability of the load adjustment compensation circuit.

[0083] Furthermore, at the instant the turn-off transistor Q1 is turned off, the junction capacitance of the turn-off transistor Q1 will also discharge, thus requiring a corresponding discharge circuit.

[0084] Based on this, the load adjustment and compensation circuit may further include: a discharge branch 160, including: a first discharge module and a second discharge module. The first discharge module is disposed between the control terminal of the selector transistor Q1 and the drive pin DRV of the control chip 130, and the second discharge module is disposed between the control terminal of the selector transistor Q1 and the current detection pin ISEN. It is adapted to feed back the junction capacitance voltage to the drive pin DRV and the current detection pin ISEN respectively when the selector transistor Q1 is turned off.

[0085] In other words, the junction voltage is released to the drive pin through the first discharge module; and the junction voltage is released to the current detection pin through the second discharge module.

[0086] In some embodiments, the first discharge module includes a second diode D3 and a first discharge resistor R19, wherein the first end of the second diode D3 is coupled to the control terminal of the gating transistor Q1, and the second end of the second diode D3 is coupled to the drive pin DRV through the first discharge resistor R19.

[0087] The second bleeder module may include a second bleeder resistor R20. The control terminal of the selection transistor Q1 releases the junction voltage to the current detection pin ISEN through the second bleeder resistor R20.

[0088] In some embodiments, when the turn-on transistor Q1 is turned off, the voltage drop across the first terminal 6 and the second terminal 7 of the compensation winding Wc is positive at the bottom and negative at the top.

[0089] Based on this, the solution also provides a freewheeling branch, which is coupled to the first end 3 of the compensation winding Wc and the ground pin GND of the control chip 130 respectively, and is suitable for providing a freewheeling path when the selection transistor Q1 is turned off.

[0090] In this embodiment, see Figure 2 The freewheeling branch includes: a third diode D4, a freewheeling resistor R21, a first freewheeling capacitor C3, and a second freewheeling capacitor C5. The first end of the freewheeling resistor R21 is coupled to the first end 3 of the compensation winding Wc. The second end of the freewheeling resistor R21 is connected to the first ground through the third diode D4 and the first freewheeling capacitor C5, and is connected to the first ground GND1 through the third diode D4 and the second freewheeling capacitor C3.

[0091] In this embodiment, the load adjustment and compensation circuit may further include: an output branch 170, coupled to the secondary winding Ws, for rectifying and filtering the output voltage on the secondary winding Ws.

[0092] Specifically, the output branch 170 may include a rectification module and a filtering module, wherein: the rectification module includes: a switching chip G1, a first rectifier resistor R22, a second rectifier resistor R23, and a rectifier capacitor C6, wherein: the first end of the switching chip G1 is coupled to the first end 4 of the secondary winding Ws, the first end of the second rectifier resistor R23, and the first end of the first rectifier resistor R22, respectively; the second end of the switching chip G1 is coupled to the second end of the second rectifier resistor R23 and the second end of the first rectifier resistor R22 through the rectifier capacitor C6, and is coupled to the filtering module and connected to the second ground GND2.

[0093] The filtering module includes: a first filtering capacitor C7, a second filtering capacitor C8, a third filtering capacitor C9, a fourth filtering capacitor C10 and a filtering resistor R24 ​​connected in parallel, and a common-mode inductor L coupled to the fourth filtering capacitor C10 and connected in parallel to the second ground GND2.

[0094] Specifically, the first filter capacitor C7, the second filter capacitor C8, the third filter capacitor C9, the fourth filter capacitor C10 and the filter resistor R24, as well as the common-mode inductor L, which are connected to the secondary winding Ws, can rectify and filter the output voltage, thereby improving the quality of the transformer voltage.

[0095] It should be noted that, in this embodiment, a mica capacitor CY is provided between the first ground GND1 and the second ground GND2.

[0096] It is understood that the above description provides multiple embodiment solutions, and the optional methods described in each embodiment solution can be combined with each other and cross-referenced without conflict, thereby extending to a variety of possible embodiment solutions, all of which can be considered as the embodiment solutions disclosed in this disclosure.

[0097] This disclosure also provides a charger, including: a load adjustment compensation circuit as described in any of the foregoing examples, and a transformer coupled to the load adjustment compensation circuit.

[0098] For details regarding the structure and working principle of the load adjustment and compensation circuit, please refer to the aforementioned example.

[0099] While the embodiments disclosed herein are as described above, this utility model is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this utility model; therefore, the scope of protection of this utility model should be determined by the scope defined in the claims.

Claims

1. A load adjustment and compensation circuit, characterized in that, Coupled to a transformer, the transformer includes: a primary winding, a secondary winding, and a compensation winding; the load adjustment and compensation circuit includes: a control chip, a selection branch, and a detection branch, wherein: The selected branch is coupled to the current detection pin of the control chip and the third terminal of the primary winding, respectively, and is adapted to be selected or turned off in response to the drive signal. When it is in the selected state, it selects the path between the third terminal of the primary winding and the first ground. The detection branch is coupled to the current detection pin, the selection branch and the first end of the compensation winding, respectively. It is adapted to perform a voltage divider operation on the voltage of the path when the path is selected, and output the corresponding detection current to the current detection pin. The equivalent voltage divider resistance value of the detection branch is variable. The control chip is configured to respond to the supply voltage by outputting a drive signal with a duty cycle to the selected branch to select the selected branch, and to adjust the duty cycle of the drive signal according to the detected current and a preset current to change the current at the first end of the compensation winding.

2. The load adjustment and compensation circuit according to claim 1, characterized in that, The detection branch includes a first detection module and a second detection module. The first detection module is coupled to the second detection module, the current detection pin and the first end of the compensation winding, respectively, and has a first equivalent resistance. The second detection module is coupled to the selection branch and connected to a first ground, and has a second equivalent resistance. When the selected branch is selected, a voltage divider operation is performed through the first equivalent resistor and the second equivalent resistor to obtain the detection current, wherein the first equivalent resistor and / or the second equivalent resistor is variable.

3. The load adjustment and compensation circuit according to claim 2, characterized in that, Meet at least one or more of the following conditions: The first detection module includes: a first detection resistor, a first diode, and a second detection resistor, wherein the first end of the first detection resistor is coupled to the second detection module and the current detection pin, and the second end of the first detection resistor is coupled to the first end of the first diode; the second end of the first diode is coupled to the first end of the compensation winding through the second detection resistor. The second detection module includes: a third detection resistor, a fourth detection resistor, a fifth detection resistor, a sixth detection resistor, and a seventh detection resistor, wherein the first end of the third detection resistor is coupled to the current detection pin and the first detection module, respectively; the second end of the third detection resistor is coupled to the first ends of the fourth, fifth, sixth, and seventh detection resistors, respectively, and the selection branch; the second ends of the fourth, fifth, sixth, and seventh detection resistors are connected to a first ground. The selection branch includes a selection transistor, the first end of which is coupled to the third end of the primary winding, and the second end of which is coupled to the current detection pin through the detection branch and connected to a first ground. It also includes: a voltage divider branch, coupled to the voltage detection pin of the control chip and the first end of the compensation winding, for detecting the voltage at the first end of the compensation winding to obtain a feedback voltage; including: a first voltage divider resistor, a second voltage divider resistor and a third voltage divider resistor, wherein the first end of the first voltage divider resistor is coupled to the voltage detection pin and the first end of the second voltage divider resistor respectively, and the second end of the first voltage divider resistor is connected to a first ground; the second end of the second voltage divider resistor is coupled to the first end of the compensation winding through the third voltage divider resistor.

4. The load adjustment and compensation circuit according to claim 2, characterized in that, The control chip also includes: A compensation pin, which is connected to the first ground in sequence through a compensation resistor and a compensation capacitor; A grounding pin is connected to the first end of the compensation winding via a grounding capacitor and to a first ground. The unused pin is coupled to the power supply pin of the control chip.

5. The load adjustment and compensation circuit according to claim 3, characterized in that, The load adjustment and compensation circuit further includes at least one or more of the following: The buffer branch is coupled to the power supply pin of the control chip and is suitable for stepping down the power supply voltage to generate a drive voltage. The discharge branch includes: a first discharge module and a second discharge module. The first discharge module is disposed between the control terminal of the gating transistor and the drive pin of the control chip, and the second discharge module is disposed between the control terminal of the gating transistor and the current detection pin. It is adapted to feed back the junction capacitance voltage to the drive pin and the current detection pin respectively when the gating transistor is turned off. The freewheeling branch is coupled to the first end of the compensation winding and the ground pin of the control chip, respectively, and is adapted to provide a freewheeling path when the gating transistor is turned off.

6. The load adjustment and compensation circuit according to claim 5, characterized in that, The first bleeder module includes: a second diode and a first bleeder resistor, wherein the first end of the second diode is coupled to the control terminal of the gating transistor, and the second end of the second diode is coupled to the drive pin through the first bleeder resistor; The second discharge module includes: a second discharge resistor; The buffer branch includes: a first buffer resistor and a second buffer resistor, wherein a first end of the first buffer resistor is adapted to receive the power supply voltage, and a second end of the first buffer resistor is coupled to the power supply pin through the second buffer resistor; The freewheeling branch includes: a third diode, a freewheeling resistor, a first freewheeling capacitor, and a second freewheeling capacitor. The first end of the freewheeling resistor is coupled to the first end of the compensation winding. The second end of the freewheeling resistor is connected to a first ground through the third diode and the first freewheeling capacitor, and is also connected to a first ground through the third diode and the second freewheeling capacitor.

7. The load adjustment and compensation circuit according to claim 1, characterized in that, The primary winding and the compensation winding are located on the same side, and the third end of the primary winding and the first end of the secondary winding are the same name ends, and the first end of the secondary winding and the first end of the compensation winding are the same name ends.

8. The load adjustment and compensation circuit according to claim 1, characterized in that, Also includes: The output branch, coupled to the secondary winding, is used to rectify and filter the output voltage on the secondary winding.

9. The load adjustment and compensation circuit according to claim 8, characterized in that, The output branch includes a rectifier module and a filter module, wherein the rectifier module includes a switching chip, a first rectifier resistor, a second rectifier resistor, and a rectifier capacitor, wherein the first end of the switching chip is coupled to the first end of the secondary winding, the second rectifier resistor, and the first end of the first rectifier resistor, respectively; the second end of the switching chip is coupled to the second end of the second rectifier resistor and the second rectifier resistor through the rectifier capacitor, and is also coupled to the filter module and connected to a second ground; The filtering module includes: a first filtering capacitor, a second filtering capacitor, a third filtering capacitor, a fourth filtering capacitor, and a filtering resistor connected in parallel, and a common-mode inductor coupled to the fourth filtering capacitor and connected in parallel to a second ground.

10. A charger, characterized in that, include: The load adjustment compensation circuit as described in any one of claims 1 to 9, and the transformer coupled to the load adjustment compensation circuit.

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