Switching tube control method, converter and power adapter

Abstract

The invention discloses a switching tube control method, a controller, a converter and a power adapter, the switching tube control method is used for controlling a first switching tube in a hybrid flyback topology converter, and the switching tube control method comprises the following steps: generating a first feedback voltage based on a current flowing through an optocoupler, and determining an operation mode based on the first feedback voltage; and outputting a second feedback voltage based on a first difference value between the voltage of the input power supply and the first voltage and the first feedback voltage, so that the same first feedback voltage can be obtained under different input power supplies and the output voltage of the hybrid flyback topological converter, the first voltage is the product of the turn ratio of the primary winding to the secondary winding and the output voltage; and controlling the first switching tube to be turned off based on the operation mode and the second feedback voltage. By means of the mode, the stability of the corresponding relation between the first feedback voltage and the output current can be improved, and debugging and power optimization are facilitated.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of switch control technology, and in particular to a switch tube control method, a converter, and a power adapter. Background Art

[0002] The hybrid flyback converter (or asymmetric half-bridge fly-back converter) combines the performance of the traditional simplified flyback topology and the resonant converter. By controlling the high-voltage side switch and the low-voltage side switch in the asymmetric half-bridge flyback topology and adjusting the positive and negative magnetizing currents, zero voltage switching can be achieved on the primary side of the transformer and zero current switching on the secondary side, thereby improving efficiency. In addition, the transformer leakage inductance energy is recovered, further improving efficiency. Hybrid flyback converters have been widely used in USB PD power adapters due to their wide operating range, ultra-high conversion efficiency and low standby power. Summary of the invention

[0003] The embodiments of the present application provide a switch tube control method, a converter, and a power adapter, which can improve the stability of the corresponding relationship between the first feedback voltage and the output current to facilitate debugging and power optimization.

[0004] In a first aspect, an embodiment of the present application provides a switch tube control method for controlling a first switch tube in a hybrid flyback topology converter, wherein the hybrid flyback topology converter further includes a controller, a second switch tube, a primary winding, a secondary winding, a capacitor and an optocoupler, wherein the first switch tube and the second switch tube are connected in series between an input power supply and ground, a connection point between the first switch tube and the second switch tube is connected to the same-name end of the primary winding, the optocoupler is connected to the opposite-name end of the secondary winding, the controller is respectively connected to the first switch tube, the second switch tube and the optocoupler, the capacitor is connected between the same-name end of the primary winding and ground or the capacitor is connected between the input power supply and the opposite-name end of the primary winding; the switch tube control method includes:

[0005] generating a first feedback voltage based on a current flowing through the optocoupler, and determining an operation mode based on the first feedback voltage;

[0006] Based on a first difference between the voltage of the input power source and the first voltage and the first feedback voltage, a second feedback voltage is output, so that the same first feedback voltage can be obtained under different input power sources and output voltages of the hybrid flyback topology converter, wherein the first voltage is the product of the turns ratio of the primary winding to the secondary winding and the output voltage;

[0007] Based on the operation mode and the second feedback voltage, the first switch tube is controlled to be turned off.

[0008] In one or more embodiments, outputting a second feedback voltage based on a first difference between the voltage of the input power source and the first voltage and the first feedback voltage includes:

[0009] The second feedback voltage is determined and output by the following formula:

[0010] V FB1 =V FB -K1×V FB ×(V IN -N1×V OUT )-K2×(V IN -N1×V OUT );

[0011] Among them, V FB1 is the second feedback voltage, V FB is the first feedback voltage, K1 is the first preset coefficient, V IN is the input power voltage, V OUT is the output voltage, N1 is the turns ratio of the primary winding to the secondary winding, and K2 is the second preset coefficient.

[0012] In one or more embodiments, the switch control method further includes:

[0013] When the output current of the hybrid flyback topology converter is a first current, adjusting the first preset coefficient so as to obtain the same first feedback voltage under different voltages of the input power supply and the output voltage, wherein the first current is an average current when the operation mode is initially configured as a discontinuous conduction mode;

[0014] When the output current of the hybrid flyback topology converter is a second current, the second preset coefficient is adjusted to obtain the same first feedback voltage under different input power supply voltages and output voltages, wherein the second current is the average current when the operation mode is initially configured as a burst mode.

[0015] In one or more embodiments, determining the operation mode based on the first feedback voltage includes:

[0016] Determining the output power of the hybrid flyback topology converter based on the first feedback voltage;

[0017] When the output power is greater than or equal to a first preset power, the operation mode is determined to be a critical conduction mode; when the output power is less than the first preset power and greater than or equal to a second preset power, the operation mode is determined to be a discontinuous conduction mode; when the output power is less than the second preset power, the operation mode is determined to be a burst mode, wherein the first preset power is greater than the second preset power.

[0018] In one or more embodiments, controlling the first switch tube to turn off based on the operation mode and the second feedback voltage includes:

[0019] In the operation mode, determining a reference voltage based on the second feedback voltage;

[0020] When the second voltage is greater than the reference voltage, the first switch tube is controlled to be turned off, wherein the second voltage is a voltage generated based on the current flowing through the primary winding.

[0021] In one or more embodiments, in the operation mode, determining a reference voltage based on the second feedback voltage includes:

[0022] When the operation mode is the critical conduction mode, the reference voltage is determined based on the following formula:

[0023] V COMP =K3×V FB ;

[0024] Among them, V COMP is the reference voltage, and K3 is the third preset coefficient.

[0025] In one or more embodiments, in the operation mode, determining a reference voltage based on the second feedback voltage includes:

[0026] When the operation mode is a discontinuous conduction mode or a burst mode, the reference voltage is determined based on the following formula:

[0027] V COMP =K3×V FB ×(T SW / (T SW -T WAIT ));

[0028] Among them, T SW To control the period of the pulse width modulation signal of the first switch tube, T WAIT is the time from when the second switch tube is turned off to when the first switch tube is turned on.

[0029] In a second aspect, an embodiment of the present application provides a hybrid flyback topology converter, including a controller, a first switch tube, a second switch tube, a primary winding, a secondary winding, a capacitor and an optocoupler;

[0030] The first switch tube and the second switch tube are connected in series between the input power supply and the ground in sequence, the connection point between the first switch tube and the second switch tube is connected to the same-name end of the primary winding, the optocoupler is connected to the opposite-name end of the secondary winding, the controller is respectively connected to the first switch tube, the second switch tube and the optocoupler, the capacitor is connected between the same-name end of the primary winding and the ground or the capacitor is connected between the input power supply and the opposite-name end of the primary winding, wherein the controller is used to execute the method as described above.

[0031] In a third aspect, an embodiment of the present application provides a power adapter, comprising the hybrid flyback topology converter as described above.

[0032] The beneficial effects of the present application are as follows: the switch control method of the embodiment of the present application is used to control the first switch in the hybrid flyback topology converter, the hybrid flyback topology converter also includes a controller, a second switch, a primary winding, a secondary winding, a capacitor and an optocoupler, the first switch and the second switch are connected in series between the input power supply and the ground, the connection point between the first switch and the second switch is connected to the same-name end of the primary winding, the optocoupler is connected to the opposite-name end of the secondary winding, the controller is respectively connected to the first switch, the second switch and the optocoupler, the capacitor is connected in series with the primary winding and then connected in parallel with the second switch. The switch control method includes: generating a first feedback voltage based on the current flowing through the optocoupler, and determining the operation mode based on the first feedback voltage; outputting a second feedback voltage based on the first difference between the voltage of the input power and the first voltage and the first feedback voltage, so that the same first feedback voltage can be obtained under different input power and output voltages of the hybrid flyback topology converter, wherein the first voltage is the product of the turns ratio of the primary winding to the secondary winding and the output voltage; based on the operation mode and the second feedback voltage, controlling the first switch to turn off. Through the above process, on the one hand, the first switch tube can be controlled. On the other hand, by controlling the first switch tube based on the same first feedback voltage obtained under different input power supplies and the output voltage of the hybrid flyback topology converter, the stability of the corresponding relationship between the first feedback voltage and the output current can be improved to facilitate debugging and power optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplary descriptions are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0034] Figure 1is a flow chart of a switch tube control method provided in an embodiment of the present application;

[0035] Figure 2 The structure of the hybrid flyback topology converter provided in the embodiment of the present application is shown in FIG. Figure 1 ;

[0036] Figure 3 The structure of the hybrid flyback topology converter provided in the embodiment of the present application is shown in FIG. Figure 2 ;

[0037] Figure 4 The control frame for controlling the first switch tube provided in the embodiment of the present application Figure 1 ;

[0038] Figure 5 The embodiment of this application provides Figure 1 A schematic diagram of an embodiment of step 101 shown in FIG.

[0039] Figure 6 is the corresponding relationship between the first feedback voltage and the output current provided in the embodiment of the present application;

[0040] Figure 7 The control frame for controlling the first switch tube provided in the embodiment of the present application Figure 2 ;

[0041] Figure 8 is a schematic diagram of the first feedback voltage and output current provided in the embodiment of the present application Figure 1 ;

[0042] Fig. 9 is a schematic diagram of the first feedback voltage and output current provided in the embodiment of the present application Figure 2 ;

[0043] Fig.10 is a schematic diagram of the first feedback voltage and output current provided in the embodiment of the present application Figure 3 ;

[0044] Fig.11 is a schematic diagram of the first feedback voltage and output current provided in the embodiment of the present application Figure 4 ;

[0045] Fig.12 The embodiment of this application provides Figure 1 A schematic diagram of an implementation of step 103 shown in FIG.

[0046] Fig.13 It is a schematic diagram of the structure of a controller for controlling a first switch tube provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0049] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0050] Please refer to Figure 1 and Figure 2 , Figure 1 A flow chart of a switch control method provided in an embodiment of the present application, Figure 2 Two structural schematic diagrams of hybrid flyback topology converters provided in the embodiments of the present application, wherein: Figure 2 Part (A1) shows a schematic diagram of the first structure; Figure 2 Part (A2) in the figure shows a second structural schematic diagram. The switch tube control method is used to control the first switch tube Q1 in the hybrid flyback topology converter 10. The hybrid flyback topology converter 10 also includes a controller U1, a second switch tube Q2, a primary winding LA1, a secondary winding LA2, a capacitor CA2 and an optocoupler U2. The first switch tube Q1 and the second switch tube Q2 are connected in series between the input power supply VI N and the ground. The connection point between the first switch tube Q1 and the second switch tube Q2 is connected to the same-name end of the primary winding LA1, and the optocoupler U2 is connected to the opposite-name end of the secondary winding LA2. The controller U1 is respectively connected to the first switch tube Q1, the second switch tube Q2 and the optocoupler U2. The capacitor CA2 is connected in series with the primary winding LA1 and then connected in parallel with the second switch tube Q2. Figure 2 As shown in part (A1) of FIG. 1 , the first switch tube Q1 and the second switch tube Q2 are connected in series from top to bottom between the input power source VI N and the ground, and the capacitor CA2 is connected between the opposite end of the primary winding LA1 and the ground; Figure 2 As shown in part (A2) of FIG. 1 , the second switch tube Q2 and the first switch tube Q1 are connected in series between the input power source VI N and the ground from top to bottom, and the capacitor CA2 is connected between the same-name end of the primary winding LA1 and the input power source.

[0051] In the embodiment of the present application, each switch tube (including the first switch tube Q1, the second switch tube Q2, and the subsequent third switch tube Q3 and the fourth switch tube Q4) is an NMOS tube as an example. The gate of the NMOS tube is the first end of each switch tube, the source of the NMOS tube is the second end of each switch tube, and the drain of the NMOS tube is the third end of each switch tube.

[0052] In addition, each switch tube can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0053] Please refer to Figure 3 , Figure 3 The circuit structure of the hybrid flyback topology converter 10 is shown as an example. Figure 3 For Figure 2 Based on the part (A1) in Figure 2 Based on the (A2) section in the previous section, the specific implementation process of the device is added. Figure 3 Similarly, no further description is given here. The hybrid flyback topology converter 10 also includes an auxiliary winding LA3, a capacitor CA1, a capacitor CA2, a capacitor CA3, a capacitor CA4, a capacitor CA5, a capacitor CA6, a capacitor CA7, a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4, a resistor RA5, a resistor RA6, a third switch tube Q3, a fourth switch tube Q4, a diode DA1, a diode DA2, a controller U3, a controller U4 and a driver U51. Among them, the first switch tube Q1, the second switch tube Q2 and the driver U51 constitute a driver chip, and the driver chip receives two pulse width modulation signals output by the controller U1, so that the driver U51 controls the first switch tube Q1 and the second switch tube Q2 respectively based on the two pulse width modulation signals, so as to drive the first switch tube Q1 and the second switch tube Q2 to alternately turn on and off. Figure 3 The connection relationship between the components in the hybrid flyback topology converter 10 is shown as follows: Figure 3 shown, and Figure 3 The specific working principle of the hybrid flyback topology converter 10 is common knowledge in the art and will not be described in detail here.

[0054] Please refer back to Figure 1 , the switch tube control method comprises the following steps:

[0055] Step 101: Generate a first feedback voltage based on a current flowing through an optocoupler, and determine an operation mode based on the first feedback voltage.

[0056] Specifically, please gather Figure 4 , Figure 4 The control block diagram for controlling the first switch tube Q1 is shown as an example, that is, the software implementation block diagram for controlling the first switch tube Q1 in the controller U1. Figure 4 As shown, a voltage is generated on the resistor RB1 by the current I U2 flowing through the optocoupler U2, and the difference between the power supply VDD voltage and the voltage on the resistor RB1 is used as the first feedback voltage V FB The first feedback voltage V FB Through the mode detection, the operation mode can be determined, wherein the operation mode is one of a critical conduction mode, a discontinuous conduction mode and a burst mode.

[0057] In some embodiments, Figure 5 As shown, the specific implementation process of determining the operation mode based on the first feedback voltage in step 101 includes the following steps:

[0058] Step 501: Determine the output power of a hybrid flyback topology converter based on a first feedback voltage.

[0059] Step 502: When the output power is greater than or equal to a first preset power, the operation mode is determined to be a critical conduction mode; when the output power is less than the first preset power and greater than or equal to a second preset power, the operation mode is determined to be a discontinuous conduction mode; when the output power is less than the second preset power, the operation mode is determined to be a burst mode, wherein the first preset power is greater than the second preset power.

[0060] Specifically, according to the first feedback voltage V FB The current I U2 flowing through the optocoupler U2 can be determined, and then the output current of the hybrid flyback topology converter 10 can be determined, so that the output power of the hybrid flyback topology converter 10 can be determined.

[0061] It can be understood that when the hybrid flyback topology converter is used in a power adapter, it generally supports multi-mode operation according to the output power of the hybrid flyback topology converter. Then, when the output power is greater than or equal to the first preset power (i.e., at high power), the operation mode is determined to be the critical conduction mode (CrM), when the output power is less than the first preset power and greater than or equal to the second preset power (i.e., at medium power), the operation mode is determined to be the discontinuous conduction mode (DCM), and when the output power is less than the second preset power (i.e., at low power), the operation mode is determined to be the burst mode (Burst Mode, Burst). Among them, the first preset power and the second preset power are pre-set powers, which can be set based on the actual application scenario. The specific implementation of the critical conduction mode, the discontinuous conduction mode and the burst mode is common knowledge in the art and will not be repeated here.

[0062] Step 102: Based on a first difference between the voltage of the input power supply and the first voltage and the first feedback voltage, a second feedback voltage is output so that the same first feedback voltage can be obtained under different input power supplies and the output voltage of the hybrid flyback topology converter, wherein the first voltage is the product of the turns ratio of the primary winding to the secondary winding and the output voltage.

[0063] Step 103: Based on the operation mode and the second feedback voltage, control the first switch tube to turn off.

[0064] By executing step 102 and step 103, on the one hand, the first switch tube Q1 can be controlled (i.e., the first switch tube Q1 is controlled to be turned off), and on the other hand, the first feedback voltage V is obtained based on the same first feedback voltage V obtained under different input power supplies and the output voltage of the hybrid flyback topology converter. FB The first feedback voltage V can be increased by controlling the first switch tube Q1. FB With the output current I OUT The stability of the corresponding relationship between them.

[0065] When Figure 4 The control block diagram shown is in static operation and when the closed-loop control is in steady state, the first feedback voltage V FB With the output current I OUT The corresponding relationship between Figure 6 As shown. Figure 6 As shown, the horizontal axis is the output current I OUT(here it is the average current); current I MAX is the maximum allowable current, exceeding which the hybrid flyback converter will automatically protect and exit the closed-loop mode; current IDCM is the output current when entering the discontinuous conduction mode; current I BST is the output current when entering the burst mode. It can be seen that the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is a linear relationship. Although, when the closed-loop control is in a transient state, such as a startup transient state, the output voltage is changing rapidly, and the first feedback voltage V FB The output voltage needs to be temporarily increased or decreased to adjust, and it is impossible to maintain the same output current I OUT The linear relationship between the control loop and the load does not affect the efficiency, because the efficiency is mainly determined by the operation of the closed-loop control in a steady state.

[0066] In practical applications, since the output current I is usually not set OUT The detection circuit can be combined with the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is a linear relationship, which can be obtained by the first feedback voltage V FB Determine the output current I OUT The size of the first feedback voltage V FB The size of the output current I OUT Based on this, the first feedback voltage V FB With the output current I OUT The stability of the corresponding relationship between the output current I OUT In the embodiment of the present application, due to the increase of the first feedback voltage V FB With the output current I OUT The stability of the corresponding relationship between can improve the determination of the output current I OUT The accuracy of the magnitude of V is thus beneficial to improving the convenience of subsequent debugging and power optimization of the hybrid flyback topology converter 10. For example, based on the first feedback voltage V FB With the output current I OUT The stability of the corresponding relationship between the first feedback voltage V FB Accurately determine the time to switch between operating modes (for example, Figure 6 As shown, the voltage VBST, the voltage VDCM and the voltage VMAX can correspond to the current IBST, the current IDCM and the current IMAX respectively. FB When the voltage is less than or equal to VBST, it enters the burst mode mode; at the first feedback voltage V FB When the voltage is less than or equal to VDCM and greater than VBST, it enters the discontinuous conduction mode; at the first feedback voltage VFB When the voltage is less than or equal to VMAX and greater than VDCM, it enters the critical conduction mode; at the first feedback voltage V FB When the voltage VMAX is greater than VMAX, the closed-loop mode is exited, thereby accurately switching between various operation modes), which greatly facilitates the debugging and power optimization of the hybrid flyback topology converter 10.

[0067] In some embodiments, the specific implementation process of outputting the second feedback voltage based on the first difference between the voltage of the input power supply and the first voltage and the first feedback voltage in step 502 includes the following steps: determining and outputting the second feedback voltage by the following formula:

[0068] V FB1 =V FB -K1×V FB ×(V IN -N1×V OUT )-K2×(V IN -N1×V OUT ).

[0069] Among them, V FB1 is the second feedback voltage, V FB is the first feedback voltage, K1 is the first preset coefficient, V IN is the input power voltage, V OUT is the output voltage, N1 is the turns ratio of the primary winding to the secondary winding, and K2 is the second preset coefficient.

[0070] The specific implementation process is as follows Figure 4 Part of the control block diagram shown in FIG20 is shown. Specifically, V IN With N1×V OUT The difference after subtraction is, on the one hand, successively compared with K1 and the first feedback voltage V FB On the other hand, multiply by K2 to get the second product, and then calculate the first feedback voltage V FB The difference between the first product and the second product is used to obtain the second feedback voltage V FB1 .

[0071] It should be noted that if Figure 4 The control block diagram shown in the figure does not include the partial control block diagram 20. Instead, after the operation mode is determined, the control block diagram 20 is directly controlled based on the first feedback voltage V FB Control the first switch tube Q1 to turn off, which is specifically implemented as follows: Figure 7 Then, in practical applications, since the components in the circuit cannot work in an ideal state, such as the inconsistency between the on-time and off-time of the switch tube or the delay of the comparator, the first feedback voltage V FB With the output current I OUTThe stability of the corresponding relationship between them is poor, and then based on the first feedback voltage V FB Unable to accurately determine the output current I OUT The accuracy of the size is not conducive to the subsequent debugging and power optimization of the hybrid flyback topology converter 10.

[0072] for example, Figure 8 An example is shown in Figure 4 In the case where the control block diagram 20 is not provided in the control block diagram shown in the figure, the output voltage V OUT Maintained at 5V, the input power supply V IN When the voltage is 150V, 200V and 400V respectively, the first feedback voltage V FB With the output current I OUT Schematic diagram of . Figure 8 The horizontal axis is the output current I OUT , the unit is A (ampere); the vertical axis is the first feedback voltage V FB , the unit is V (volt); each straight line is an input power supply V IN The voltage corresponding to the first feedback voltage V FB With the output current I OUT . Based on the fact that the three straight lines do not overlap, it can be seen that Figure 4 In the case where the control block diagram 20 is not provided in the control block diagram shown in the figure, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them will change with the input power supply V IN The voltage changes and is not stable. It cannot be changed at different input power supplies V IN The voltage is directly fixed with the first feedback voltage V FB To represent the output current I OUT , it is impossible to FB Accurately determine the timing to switch between operating modes.

[0073] Another example: Fig. 9 An example is shown in Figure 4 In the case where the control block diagram 20 is not provided in the control block diagram shown in the figure, the input power supply V IN The voltage is kept at 400V, and the output voltage V OUT The first feedback voltage V is 5V, 9V, 15V and 28V respectively FB With the output current I OUT Schematic diagram of . Fig. 9 The horizontal axis is the output current I OUT , the unit is A (ampere); the vertical axis is the first feedback voltage V FB , the unit is V (volt); each straight line is an output voltage V OUTThe corresponding first feedback voltage V FB With the output current I OUT . Based on the fact that the three straight lines do not overlap, it can be seen that Figure 4 In the case where the control block diagram 20 is not provided in the control block diagram shown in the figure, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them will change with the output voltage V OUT The output voltage V OUT Directly use the fixed first feedback voltage V FB To represent the output current I OUT , it is impossible to FB Accurately determine the timing to switch between operating modes.

[0074] In summary, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is not fixed and will be affected by the input power supply V IN The voltage and output voltage V OUT In this case, it is impossible to achieve the effect of the first feedback voltage V FB Accurately determining the time to switch between the operation modes is not conducive to subsequent debugging and power optimization of the hybrid flyback topology converter 10 .

[0075] The embodiment of the present application can solve the above problem by setting a part of the control block diagram 20 to increase the first feedback voltage V FB With the output current I OUT The stability of the corresponding relationship between them. The specific description is as follows:

[0076] First, as is well known, based on the structure of the hybrid flyback topology converter 10, according to the rising process of the current flowing through the primary winding LA1, the following formula can be obtained theoretically:

[0077] V COMP =T ON_HS ×(V IN -N1×V OUT ) / (L M +L R ).

[0078] Among them, T ON_HS is the conduction time of the first switch tube Q1 in one cycle, L M is the inductance of the primary winding LA1, L Ris the leakage inductance of the transformer. In actual operation, the delay of the comparator and the turn-on delay / turn-off delay of the switch tube will cause the above formula to be inaccurate. The impact caused by these time errors is proportional to the rising slope of the current, that is, (V IN -N1×V OUT ) is proportional. Based on this, the embodiment of the present application provides a feedforward method by IN -N1×V OUT ) is introduced into a control loop, and two configurable parameters (i.e., a first preset coefficient K1 and a second preset coefficient K2) are introduced to achieve the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is adjusted, thereby increasing the first feedback voltage V FB With the output current I OUT The stability of the corresponding relationship between them.

[0079] Specifically, in some embodiments, the switch control method further includes the following steps: when the output current of the hybrid flyback topology converter 10 is the first current, adjusting the first preset coefficient K1 to adjust the output current of the hybrid flyback topology converter 10 to the first current at different input power supplies V IN The voltage and output voltage V OUT The same first feedback voltage V FB (The first feedback voltage V FB With the output current I OUT The corresponding relationship between them can be kept stable), wherein the first current is the average current when the operation mode is configured as the discontinuous conduction mode at the beginning (that is, the first current corresponds to the current IDCM in the above embodiment); when the output current of the hybrid flyback topology converter 10 is the second current, the second preset coefficient K2 is adjusted to IN The voltage and output voltage V OUT The same first feedback voltage V FB , wherein the second current is the average current when the operation mode is initially configured as the burst mode (ie, the second current corresponds to the current I BST in the above embodiment).

[0080] In this embodiment, by introducing IN -N1×V OUT ) related feedforward control, which is equivalent to an active reverse operation, can eliminate the different input power supplies V IN The voltage and output voltage V OUT The first feedback voltage V FB With the output current I OUT The influence of the corresponding relationship between them.

[0081] Fig.10 An example is shown in Figure 4 Under the control block diagram shown, the output voltage V OUT Maintained at 5V, the input power supply V IN The first feedback voltage V is 150V, 200V, 250V, 300V, 350V and 400V respectively. FB With the output current I OUT Schematic diagram of . Fig.10 The horizontal axis is the output current I OUT , the unit is A (ampere); the vertical axis is the first feedback voltage V FB , the unit is V (volt); each straight line is an input power supply V IN The first feedback voltage and output current corresponding to the voltage of Figure 4 In the control block diagram shown, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is consistent, that is, it is relatively stable and is affected by the input power supply V IN The voltage has little effect.

[0082] Fig.11 An example is shown in Figure 4 In the control block diagram shown, the input power supply V IN The voltage is kept at 400V, and the output voltage V OUT The first feedback voltage V is 5V, 9V, 12V, 15V, 20V and 28V respectively FB With the output current I OUT Schematic diagram of . Fig.11 The horizontal axis is the output current I OUT , the unit is A (ampere); the vertical axis is the first feedback voltage V FB , the unit is V (volt); each straight line is an output voltage V OUT The corresponding first feedback voltage V FB With the output current I OUT Based on the basic overlap of the six straight lines, it can be seen that Figure 4 In the control block diagram shown, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is consistent, that is, it is relatively stable and is affected by the input power supply V IN The voltage has little effect.

[0083] In summary, the first feedback voltage V FB With the output current I OUT The corresponding relationship between them is relatively fixed and will not be affected by the input power supply V IN The voltage and output voltage V OUTIn this case, based on the first feedback voltage V FB Accurately determining the time to switch between the operation modes is beneficial to providing convenience for subsequent debugging and power optimization of the hybrid flyback topology converter 10 .

[0084] In some embodiments, Fig.12 As shown, the specific implementation process of controlling the first switch tube to turn off based on the operation mode and the second feedback voltage in step 103 includes the following steps:

[0085] Step 1201: In operation mode, determine a reference voltage based on a second feedback voltage.

[0086] Specifically, in one of the critical conduction mode, the discontinuous conduction mode or the burst mode, based on the second feedback voltage V FB1 Determine the reference voltage V COMP .

[0087] In some embodiments, in step 1201, in the operation mode, the specific implementation process of determining the reference voltage based on the second feedback voltage includes the following steps: when the operation mode is the critical conduction mode, the reference voltage is determined based on the following formula: V COMP =K3×V FB ; Among them, V COMP is the reference voltage, and K3 is the third preset coefficient.

[0088] In some embodiments, in step 1201, in the operation mode, the specific implementation process of determining the reference voltage based on the second feedback voltage includes the following steps: when the operation mode is the discontinuous conduction mode or the burst mode, the reference voltage is determined based on the following formula: V COMP =K3×V FB ×(T SW / (T SW -T WAIT )); where T SW To control the period of the pulse width modulation signal of the first switch tube, T WAIT is the time from when the second switch tube is turned off to when the first switch tube is turned on.

[0089] Step 1202: When the second voltage is greater than the reference voltage, control the first switch tube to turn off, wherein the second voltage is a voltage generated based on the current flowing through the primary winding.

[0090] like Figure 4 As shown in FIG. 1 , the current flowing through the primary winding is the current I LA1. The current I LA1 flows through the resistor RB2 to generate a second voltage. The comparator U6 converts the reference voltage V COMP Compare with the second voltage, if the second voltage is greater than the reference voltage V COMP, then a signal for controlling the first switch tube Q1 is output to control the first switch tube Q1 to turn off. In addition, after the first switch tube Q1 is turned off, the first switch tube Q1 will be turned on at the specified valley bottom of the resonant voltage in the next cycle. The specific implementation process is common knowledge in the art and will not be repeated here. In some embodiments, the above-mentioned signal for controlling the first switch tube Q1 to turn on and off is input to a module for generating a pulse width modulation signal, which can generate a pulse width modulation signal for controlling the first switch tube Q1.

[0091] In some implementations, the switch control method provided in the embodiments of the present application may also be implemented by a digital circuit or an analog circuit. For example, a high-frequency analog-to-digital converter ADC may be used to sample the first feedback voltage V FB voltage; then, the feedforward function, the mode detection function and the reference voltage V determined in different modes COMP The calculations can be realized by digital logic circuits; then, a high-speed digital-to-analog converter DAC can be used to convert the reference voltage V COMP Convert to analog signal; Finally, convert the current flowing through the primary winding LA1 into an analog voltage signal and compare it with the reference voltage V COMP The converted analog signals are compared to generate a signal for controlling the first switch tube Q1.

[0092] Please refer to Fig.13 , Fig.13 Schematic diagram of the composition block diagram of the controller provided in the embodiment of the present application. Fig.13 As shown, the controller 1300 includes one or more processors 1301 and a memory 1302. Fig.10 A processor 1301 is taken as an example.

[0093] The processor 1301 and the memory 1302 may be connected via a bus or other means. Fig.13 The example of connecting through bus is taken in the following.

[0094] The memory 1302 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules. The processor 1301 executes various functional applications and data processing of the terminal interaction device by running the non-volatile software programs, instructions and modules stored in the memory 1302, that is, implements the switch control method in the above method embodiment.

[0095] The memory 1302 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the memory 1302 may optionally include a memory remotely arranged relative to the processor 1301, and these remote memories may be connected to the processor 1301 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0096] The program instructions / modules are stored in the memory 1302, and when executed by the one or more processors 1301, the switch control method in any of the above method embodiments is executed, for example, the above described Figure 1 , Figure 5 and Fig.12 The steps shown.

[0097] In some embodiments, Figure 2 and Figure 3 The controller U1 shown is implemented as Fig.13 The structure of the controller 1300 is shown.

[0098] An embodiment of the present application also provides a non-volatile computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed, the switch tube control method in any embodiment of the present application is implemented.

[0099] An embodiment of the present application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the switch tube control method in any embodiment of the present application.

[0100] An embodiment of the present application further provides a power adapter, which includes the hybrid flyback topology converter 10 in any embodiment of the present application.

[0101] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0102] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A switch tube control method, characterized in that: Used to control the first switch tube in a hybrid flyback topology converter, the hybrid flyback topology converter also includes a controller, a second switch tube, a primary winding, a secondary winding, a capacitor and an optocoupler, the first switch tube and the second switch tube are connected in series between an input power supply and ground, the connection point between the first switch tube and the second switch tube is connected to the same-name end of the primary winding, the optocoupler is connected to the opposite-name end of the secondary winding, the controller is respectively connected to the first switch tube, the second switch tube and the optocoupler, the capacitor is connected in series with the primary winding and then connected in parallel with the second switch tube; The switch tube control method comprises: generating a first feedback voltage based on a current flowing through the optocoupler, and determining an operation mode based on the first feedback voltage; Based on a first difference between the voltage of the input power source and the first voltage and the first feedback voltage, a second feedback voltage is output, so that the same first feedback voltage can be obtained under different input power sources and output voltages of the hybrid flyback topology converter, wherein the first voltage is the product of the turns ratio of the primary winding to the secondary winding and the output voltage; Based on the operation mode and the second feedback voltage, the first switch tube is controlled to be turned off.

2. The switch tube control method according to claim 1, characterized in that: The step of outputting a second feedback voltage based on a first difference between the voltage of the input power source and the first voltage and the first feedback voltage comprises: The second feedback voltage is determined and output by the following formula: V FB1 =V FB -K1×V FB ×(V IN -N1×V OUT )-K2×(V IN -N1×V OUT ); Among them, V FB1 is the second feedback voltage, V FB is the first feedback voltage, K1 is the first preset coefficient, V IN is the input power voltage, V OUT is the output voltage, N1 is the turns ratio of the primary winding to the secondary winding, and K2 is the second preset coefficient.

3. The switch control method according to claim 2, characterized in that: The switch tube control method further includes: When the output current of the hybrid flyback topology converter is a first current, adjusting the first preset coefficient so as to obtain the same first feedback voltage under different voltages of the input power supply and the output voltage, wherein the first current is an average current when the operation mode is initially configured as a discontinuous conduction mode; When the output current of the hybrid flyback topology converter is a second current, the second preset coefficient is adjusted to obtain the same first feedback voltage under different input power supply voltages and output voltages, wherein the second current is the average current when the operation mode is initially configured as a burst mode.

4. The switch control method according to claim 1, characterized in that: The determining of the operation mode based on the first feedback voltage comprises: Determining the output power of the hybrid flyback topology converter based on the first feedback voltage; When the output power is greater than or equal to a first preset power, the operation mode is determined to be a critical conduction mode; when the output power is less than the first preset power and greater than or equal to a second preset power, the operation mode is determined to be a discontinuous conduction mode; when the output power is less than the second preset power, the operation mode is determined to be a burst mode, wherein the first preset power is greater than the second preset power.

5. The switch tube control method according to any one of claims 1 to 4, characterized in that: The controlling the first switch tube to turn off based on the operation mode and the second feedback voltage includes: In the operation mode, determining a reference voltage based on the second feedback voltage; When the second voltage is greater than the reference voltage, the first switch tube is controlled to be turned off, wherein the second voltage is a voltage generated based on the current flowing through the primary winding.

6. The switch control method according to claim 5, characterized in that: In the operation mode, determining a reference voltage based on the second feedback voltage includes: When the operation mode is the critical conduction mode, the reference voltage is determined based on the following formula: In COMP =K3×V FB ; Among them, V COMP is the reference voltage, and K3 is the third preset coefficient.

7. The switch control method according to claim 5, characterized in that: In the operation mode, determining a reference voltage based on the second feedback voltage includes: When the operation mode is a discontinuous conduction mode or a burst mode, the reference voltage is determined based on the following formula: V COMP =K3×V FB ×(T SW / (T SW -T WAIT )); Among them, T SW To control the period of the pulse width modulation signal of the first switch tube, T WAIT is the time from when the second switch tube is turned off to when the first switch tube is turned on.

8. A hybrid flyback topology converter, characterized in that: It includes a controller, a first switch tube, a second switch tube, a primary winding, a secondary winding, a capacitor and an optical coupler; The first switch tube and the second switch tube are connected in series between the input power supply and the ground, the connection point between the first switch tube and the second switch tube is connected to the same-name end of the primary winding, the optocoupler is connected to the opposite-name end of the secondary winding, the controller is respectively connected to the first switch tube, the second switch tube and the optocoupler, the capacitor is connected in series with the primary winding and then connected in parallel with the second switch tube, wherein the controller is used to execute the method described in any one of claims 1 to 7.

9. A power adapter, characterized in that: It comprises the hybrid flyback topology converter as claimed in claim 8.

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