Switching type regulating driver and regulating driving method thereof

Abstract

The present invention discloses a switch-type regulating driver and a regulating driving method thereof, wherein the switch-type regulating driver comprises: a transformer; a first transistor; a controller; a synchronous rectifier; and a driving control module, which are respectively connected to the opposite-name end of the synchronous rectifier and the secondary winding, and are used to detect the target parameters of the voltage at the two power ends of the synchronous rectifier when the synchronous rectifier disconnects the conductive path between the opposite-name end of the secondary winding and the reference ground, and trigger the controller to control the primary winding to transmit power to the secondary winding when it is detected that the target parameters of the voltage at the two power ends of the synchronous rectifier meet the preset conditions. The present invention detects the information of the voltage at the two power ends of the synchronous rectifier and indirectly samples the information of the output voltage, thereby matching with the previous chip to realize the function of dynamic acceleration and reduce the dependence on the output pin.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a switch type regulating driver and a regulating driving method thereof. Background Art

[0002] Different electrical / electronic devices operate at specific operating voltages. For example, integrated circuits (ICs) are generally powered by 5V, 3V, or 1.8V, while high-voltage devices require 110V or 220V AC from the mains. In particular, the lamps of light-emitting diode (LED) displays need to operate at higher operating voltages. Therefore, many power converters have been developed to meet different requirements.

[0003] These power converters include SSR (secondary side regulation) and PSR (primary side regulation). In PSR applications, the secondary output voltage can only be captured 2-3uS after the secondary demagnetization begins. When unloaded, it is usually necessary to lightly turn on again after a few mS or tens of mS after demagnetization and resonance to detect the output voltage. If it is turned on frequently, the output voltage will float, which will increase the power consumption of the dummy load and reduce efficiency. Therefore, if the output is suddenly loaded during the no-load period, the output voltage will suddenly drop, and it cannot be fed back to the primary in time. If the output voltage information is detected by the auxiliary winding in the switching cycle, the output voltage cannot be detected in real time. When the load is very light, the switching frequency can be as low as several hundred Hz. Under this condition, when switching from no-load to full load, it takes 1-2 cycles (up to several ms) for the front-stage chip to detect the output voltage. During this period, energy cannot be transmitted to the output, and the output voltage will drop to a lower level or even to 0V due to the consumption of the load.

[0004] In order to solve the above problems, the common practice is to directly detect the output voltage information. When the output voltage is lower than the set threshold, the auxiliary winding transmits the relevant signal to the front-stage chip. After the front-stage chip receives the relevant signal, it immediately sends a drive signal to transmit power to the output to avoid the output voltage drop as much as possible. However, directly detecting the output voltage requires setting a specific output voltage feedback pin, which is not conducive to the miniaturization of the driver.

[0005] Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a switching type regulating driver and a regulating driving method thereof, which detects the voltage information of the two power terminals of the synchronous rectifier tube and indirectly samples the output voltage information, thereby matching with the previous chip to realize the dynamic acceleration function and reduce the dependence on the output pin.

[0007] On the one hand, a switching type regulating driver provided according to the present invention includes: a transformer including a primary winding and a secondary winding; a first transistor, a first power end of which is connected to the same-name end of the primary winding, and a second power end of which is connected to a reference ground through a current sensing resistor; a controller, connected to a control end and a second power end of the first transistor respectively; a synchronous rectifier, connected between the opposite-name end of the secondary winding and the reference ground; a drive control module, connected to the control end of the synchronous rectifier and the opposite-name end of the secondary winding respectively, wherein the drive control module is used to detect the target parameters of the voltage at the two power ends of the synchronous rectifier when the synchronous rectifier disconnects the conductive path between the opposite-name end of the secondary winding and the reference ground, and when it is detected that the target parameters of the voltage at the two power ends of the synchronous rectifier meet preset conditions, the controller controls the switching action of the first transistor to enable the primary winding to transfer power to the secondary winding.

[0008] Optionally, the switch-type regulating driver also includes: the driver also includes an auxiliary winding, and the voltage signal at the two power ends of the auxiliary winding is divided by a voltage dividing resistor to generate a voltage dividing signal that is transmitted to the controller, and the controller controls the switching action of the first transistor according to the information of the voltage dividing signal.

[0009] Optionally, the switch-type regulating driver further includes: an input capacitor, one end of which is connected to the opposite-name end of the primary winding, and the other end is connected to a reference ground; an output capacitor, one end of which is connected to the same-name end of the secondary winding, and the other end is connected to a reference ground.

[0010] Optionally, the drive control module includes: a second transistor and a first resistor, the second transistor and the first resistor are connected in series between the opposite-name ends of the secondary winding and a reference ground in sequence; a sampling unit, connected to the opposite-name ends of the secondary winding, for sampling the voltage between the two power ends of the synchronous rectifier to obtain the voltage at the two power ends of the synchronous rectifier; a drive control unit, respectively connected to the sampling unit, the control end of the synchronous rectifier and the control end of the second transistor, for providing a second control signal to the synchronous rectifier, and providing a third control signal to the second transistor according to the voltage at the two power ends of the synchronous rectifier.

[0011] Optionally, the drive control unit includes: a control signal generator, including a first output end for providing the second control signal, and a second output end for providing the third control signal, and a driver connected between the first output end of the control signal generator and the control end of the synchronous rectifier.

[0012] Optionally, the target parameter of the voltage at two power ends of the synchronous rectifier is a voltage amplitude of the voltage at two power ends of the synchronous rectifier, and the preset condition is that the voltage amplitude is less than or equal to a first threshold.

[0013] Optionally, the first threshold is a preset fixed value; or the first threshold is adaptively adjusted following the voltage at two power terminals of the synchronous rectifier.

[0014] Optionally, when the first threshold is adaptively adjusted following the voltage at the two power ends of the synchronous rectifier, the drive control module also includes: a sampling, filtering and holding unit connected to the opposite end of the secondary winding, for sampling and filtering the voltage between the two power ends of the synchronous rectifier to obtain the average value of the voltage at the two power ends of the synchronous rectifier; a proportional adjustment unit, respectively connected to the sampling, filtering and holding unit and the drive control unit, for obtaining the first threshold according to the average value of the voltage at the two power ends of the synchronous rectifier and a preset proportional coefficient, wherein the first threshold is the product of the average value and the preset proportional coefficient, and the preset proportional coefficient is denoted as K%, where K is greater than or equal to 80 and less than 100.

[0015] Optionally, the target parameter of the voltage at two power ends of the synchronous rectifier is a decreasing slope of the voltage at two power ends of the synchronous rectifier, and the preset condition is that the decreasing slope is greater than a second threshold.

[0016] Optionally, the drive control module also includes: a timing unit, connected to the drive control unit, for re-timing each time a rising edge of the second control signal is detected, and triggering the drive control module to detect the target parameters of the voltage at the two power ends of the synchronous rectifier when the timing value reaches a third threshold.

[0017] Optionally, the switch-type regulating driver further includes: a second resistor, a first capacitor and a first diode, wherein the second resistor and the first capacitor are connected in parallel to each other and connected between the opposite-name end of the primary winding and the cathode of the first diode, and the anode of the first diode is connected to the same-name end of the primary winding.

[0018] Optionally, the first transistor, the synchronous rectifier and the second transistor are all NMOS transistors.

[0019] On the other hand, a switching power supply provided according to the present invention includes: the switching type regulating drive circuit as described above.

[0020] On the other hand, according to a switching type regulation driving method provided by the present invention, the switching type regulation driving method can be applied to the switching type regulation driving circuit as mentioned above, specifically including: allowing a first current pulse to flow through the primary winding of the transformer, and forming a second current pulse on the secondary winding of the transformer based on a first control signal; inputting the second control signal to the control end of the synchronous rectifier, and the synchronous rectifier rectifying the second current pulse to form an output voltage, wherein the method also includes: detecting target parameters of the voltage at the two power ends of the synchronous rectifier, and when it is detected that the target parameters of the voltage at the two power ends of the synchronous rectifier meet preset conditions, triggering the controller to control the primary winding to transfer power to the secondary winding.

[0021] Optionally, detecting target parameters of the voltage at the two power ends of the synchronous rectifier, and when detecting that the target parameters of the voltage at the two power ends of the synchronous rectifier meet preset conditions, triggering the controller to control the primary winding to transfer power to the secondary winding includes: detecting the voltage amplitude of the voltage at the two power ends of the synchronous rectifier, and when detecting that the voltage amplitude of the voltage at the two power ends of the synchronous rectifier is less than or equal to a first threshold, triggering the controller to control the primary winding to transfer power to the secondary winding.

[0022] Optionally, detecting target parameters of the voltage at the two power ends of the synchronous rectifier, and when detecting that the target parameters of the voltage at the two power ends of the synchronous rectifier meet preset conditions, triggering the controller to control the primary winding to transfer power to the secondary winding includes: detecting the falling slope of the voltage at the two power ends of the synchronous rectifier, and when detecting that the falling slope of the voltage at the two power ends of the synchronous rectifier is greater than a second threshold, triggering the controller to control the primary winding to transfer power to the secondary winding.

[0023] Optionally, the trigger controller controls the primary winding to transfer power to the secondary winding, including: generating a third control signal having a first frequency, and forming a third current pulse on the secondary winding based on the third control signal; forming an induced current on the auxiliary winding of the transformer based on the third current pulse, and forming a trigger signal to the controller based on the induced current; the trigger signal triggers the controller to control the current loop where the primary winding is located to be turned on, thereby transferring power to the secondary winding.

[0024] Optionally, before detecting the target parameters of the voltage at the two power ends of the synchronous rectifier, the method also includes: detecting the rising edge of the second control signal, and retiming each time the rising edge of the second control signal is detected; when the timing value reaches a third threshold, triggering the detection of the target parameters of the voltage at the two power ends of the synchronous rectifier.

[0025] The beneficial effects of the present invention are as follows: the present invention discloses a switch-type regulating driver and a regulating driving method thereof, wherein a driving control module is arranged at the secondary winding end of the driver, and the driving control module detects the target parameters of the voltages at the two power ends of the synchronous rectifier tube, thereby achieving the purpose of indirectly sampling the output voltage information, thereby matching with the previous chip to realize the function of dynamic acceleration, avoiding output voltage drop, and at the same time reducing the dependence on the output pins, and even saving output pins.

[0026] The first threshold value is adaptively adjusted to follow the voltage at the two power ends of the synchronous rectifier tube, so that when the output voltage fluctuates greatly and the gap from the first threshold value is also large, the dynamic response can be accelerated to avoid the output voltage from dropping too much.

[0027] The timing unit is used to re-time after detecting the rising edge of the second control signal, and the target parameter is detected when the timing value reaches the third threshold value, so that the accuracy and reliability of the detection can be improved.

[0028] It should be noted that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings.

[0030] Figure 1 A schematic diagram of the circuit structure of an existing switch type regulating driver is shown;

[0031] Figure 2 A schematic diagram of the circuit structure of a switch-type regulating driver provided according to an embodiment of the present disclosure is shown;

[0032] Figure 3 A schematic diagram of the circuit structure of a driving control unit in a switch-type regulating driver provided according to an embodiment of the present disclosure is shown;

[0033] Figure 4a and Figure 4b Schematic diagrams of signal waveforms of switch-type regulating drivers provided according to different embodiments of the present disclosure are respectively shown;

[0034] Figure 5 A flow chart of a switch-type regulating driving method provided according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0037] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0038] Figure 1 A schematic diagram of the circuit structure of an existing switch-type regulating driver is shown.

[0039] like Figure 1 As shown, the switch type regulating driver includes: a transformer TR, an input capacitor C1, a first transistor Q1, a current sensing resistor Rs, a controller U1, a synchronous rectifier Q2, an output capacitor Co and a driving controller 10. The transformer TR includes a primary winding N P , secondary winding N S and auxiliary winding N A One end of the input capacitor C1 receives the input voltage Vin and is connected to the primary winding N P The other end of the input capacitor C1 is connected to the reference ground. The first power terminal of the first transistor Q1 is connected to the primary winding N P The second power terminal of the first transistor Q1 is connected to the reference ground through the current sensing resistor Rs. One end of the output capacitor Co is connected to the secondary winding N S The other end of the output capacitor Co is connected to the reference ground. The output capacitor Co is connected in parallel with an equivalent load R L The synchronous rectifier Q2 is connected to the secondary winding N S The first transistor Q1 is, for example, an NMOS transistor.

[0040] The drive controller 10 includes: a GT_SR (second control signal output) pin, a GND (reference ground) pin, a Fo (output voltage detection) pin, and a SW (feedback regulation) pin. The GT_SR pin is connected to the control end of the synchronous rectifier Q2, the GND pin is connected to the reference ground, the Fo pin is connected to the DC output voltage Vo output end, and the SW pin is connected to the secondary winding N S The synonym end.

[0041] The controller U1 includes but is not limited to: VDD (supply voltage input) pin, GND (reference ground) pin, GT_PSR (gate drive output) pin, CS (current sense input) pin and VS (voltage sense input) pin. The VDD pin is connected to the auxiliary winding N via a voltage regulator (including a second diode D2 and a third capacitor C3). A The GND pin is connected to the reference ground, the GT_PSR pin is connected to the control terminal of the first transistor Q1, the CS pin is connected to the connection node of the first transistor Q1 and the current sensing resistor Rs, and the VS pin is connected to the connection node of the voltage divider (including the third resistor R2 and the fourth resistor R3), and the voltage divider is connected to the auxiliary winding N A Between the homonymous end and the heteronymous end.

[0042] When the controller U1 controls the first transistor Q1 to turn on, the input voltage Vin is connected to the primary winding N of the transformer TR. P , the first transistor Q1 and the current sensing resistor RS form a current loop to the reference ground, and the primary winding N of the transformer TR P Start to store energy, and at the same time, the auxiliary winding N A The VS pin of the controller U1 senses a slightly negative / positive potential, and the current sensing signal captured from the current sensing resistor Rs is fed to the Cs pin of the controller U1. S When the synchronous rectifier Q2 at the end is turned on, the primary winding N P Energy begins to be released and converted into a DC output voltage Vo across the output capacitor Co, so that some devices that require DC power can operate. At this time, the VS pin of the controller U1 senses a proportionally reduced positive voltage for switch-type regulation, and the Cs pin of the controller U1 does not receive a current sensing signal. Then the controller U1 can combine the voltage sensing signal received by its Vs pin and the current sensing signal received by its Cs pin to obtain the current load status.

[0043] Based on Figure 1 When the switch type regulating driver circuit shown in the figure detects the voltage of the DC output voltage Vo, it can only directly detect the output voltage information through the Fo pin of the driving controller 10. When the output voltage is lower than the set threshold, the secondary winding N is switched on through the SW pin. SThe voltage or current on the driver is fed back and regulated, and then the relevant signal is transmitted to the front-stage chip through the auxiliary winding. After receiving the relevant signal, the front-stage chip immediately outputs a driving signal to transmit power to the output to avoid output voltage drop as much as possible. Since detection must be performed at the output end of the driver, the dependence on the Fo pin of the drive controller 10 will be relatively large, which is not conducive to the miniaturization of the driver.

[0044] Based on this, the present disclosure Figure 1 The circuit shown in FIG. 1 is improved to overcome the above technical problems. The circuit structure of the improved switch type regulating driver is as follows: Figure 2 and Figure 3 As shown. Among them, Figure 2 The improved switch-type regulation driver shown in the figure is Figure 1 The same circuit structure of the switch type regulating driver shown will not be repeated here. For details, please refer to Figure 1 Description. Figure 2 FIG. 1 is a schematic diagram showing a circuit structure of a switch-type regulating driver provided according to an embodiment of the present disclosure. Figure 3 FIG. 1 is a schematic diagram showing a circuit structure of a driving control unit in a switch-type regulating driver provided according to an embodiment of the present disclosure, Figure 4a and Figure 4b Schematic diagrams of signal waveforms of switch-type regulating drivers provided according to different embodiments of the present disclosure are respectively shown.

[0045] like Figure 2 As shown, in this embodiment, the switch type regulating driver includes: a driving control module 20. The driving control module 20 includes a GT_SR (second control signal output) pin, a GND (reference ground) pin, and a SW (feedback regulation) pin. The GT_SR pin is connected to the control end of the synchronous rectifier Q2, the GND pin is connected to the reference ground, and the SW pin is connected to the secondary winding N S The synonym end.

[0046] The drive control module 20 is used to disconnect the secondary winding N when the synchronous rectifier Q2 S When the conductive path between the opposite-name terminal and the reference ground is formed, the target parameters of the voltage at the two power terminals of the synchronous rectifier Q2 are detected through the SW pin, and when it is detected that the target parameters of the voltage at the two power terminals of the synchronous rectifier Q2 meet the preset conditions, the controller U1 controls the switching action of the first transistor Q1 to make the primary winding N P To the secondary winding N S Transmission power / energy. In the present disclosure, voltage sampling detection and feedback regulation are simultaneously implemented based on the SW pin of the drive control module 20, so there is no need to set an additional output voltage feedback pin, saving the number of pins.

[0047] Furthermore, in this embodiment, the first power terminal of the synchronous rectifier Q2 is connected to the secondary winding N S The second power terminal of the synchronous rectifier Q2 is connected to the reference ground, and the control terminal of the synchronous rectifier Q2 is connected to the drive control module 20 to receive the second control signal GT_SR. The synchronous rectifier Q2 is, for example, an NMOS transistor. Using a synchronous rectifier (NMOS transistor) as a rectifier to synchronously rectify the current of the secondary winding can reduce rectification losses.

[0048] It is understandable that when the load R L When the load R is very light, the switching frequency of the first transistor Q1 and the synchronous rectifier Q2 is low, for example, usually at the level of hundreds of Hz or kHz. After several resonant cycles, the voltage at the two power ends of the synchronous rectifier Q2 (that is, the source-drain voltage of the synchronous rectifier Q2) VDS_S is equal to the output voltage Vo. L When switching from light load to heavy load instantaneously, the voltage VDS_S at the two power ends of the synchronous rectifier Q2 drops synchronously with the drop of the output voltage Vo. Therefore, the detection of the target parameter of the voltage VDS_S at the two power ends of the synchronous rectifier in the present disclosure is almost equal to the detection of the output voltage Vo, thereby achieving the purpose of indirectly sampling the output voltage Vo information, thereby matching with the previous chip to realize the function of dynamic acceleration, avoiding the output voltage drop, and at the same time reducing the dependence on the output feedback pin, reducing the number of chip pins.

[0049] Furthermore, in this embodiment, the driving control module 20 includes: a second transistor Q3, a first resistor R4, a sampling unit 22 and a driving control unit 21. The second transistor Q3 and the first resistor R4 are connected in series to the secondary winding N S The sampling unit 22 and the secondary winding N S The driving control unit 21 is connected to the sampling unit 22, the control end of the synchronous rectifier Q2 and the control end of the second transistor Q3, respectively, to provide the second control signal GT_SR to the synchronous rectifier Q2, and to provide the third control signal GT_DY to the second transistor Q3 according to the voltage VDS_S at the two power ends of the synchronous rectifier. The second transistor Q3 is, for example, an NMOS transistor.

[0050] For example, Figure 3As shown, the driving control unit 21 includes: a control signal generator 211 and a driver 212. The control signal generator 211 includes a first output terminal 1 for providing a second control signal GT_SR, and a second output terminal 2 for providing a third control signal GT_DY. The driver 212 is connected between the first output terminal 1 of the control signal generator 211 and the control terminal of the synchronous rectifier Q2, and operates based on the power supply VCC and the reference ground. If the second control signal GT_SR generated by the control signal generator 211 is a digital signal, it can be converted into an analog signal by the driver 212 and then output to the synchronous rectifier Q2, so as to better realize the driving control of the synchronous rectifier Q2. Based on the same principle, the same driver can also be set between the second output terminal 2 of the control signal generator 211 and the control terminal of the second transistor Q3.

[0051] In one embodiment of the present disclosure, the target parameter of the voltage VDS_S at the two power terminals of the synchronous rectifier Q2 is the voltage amplitude of the voltage VDS_S at the two power terminals of the synchronous rectifier, and the preset condition to be satisfied is that the voltage amplitude of the voltage VDS_S at the two power terminals of the synchronous rectifier is less than or equal to the first threshold. Figure 4a When the switch-type regulating driver is working normally, the first control signal GT_PSR and the second control signal GT_SR are at normal driving frequencies. The normal operation of the switch-type regulating driver generally includes the following: during the period from t0 to t1, the first control signal GT_PSR is at a high level, the first transistor Q1 is turned on, and the auxiliary winding N A At the same time, the second control signal GT_SR is at a low level, the synchronous rectifier Q2 is turned off, and the voltage VDS_S at both power terminals is greater than the output voltage Vo. During the period from t1 to t2, the first control signal GT_PSR is at a low level, the first transistor Q1 is turned off, the second control signal GT_SR is at a high level, the synchronous rectifier Q2 is turned on, and the output voltage Vo is transmitted through the secondary winding N S The synchronous rectifier Q2 forms a conduction loop to the reference ground, and the voltage VDS_S at the two power terminals of the synchronous rectifier Q2 becomes negative. At this time, the auxiliary winding N A Both ends form a secondary winding N based on SThe induced voltage is sensed by the VS pin of the controller U1. Starting from time t2, after several resonant cycles (including times t2, t3 and t4), the voltage VDS_S across the source and drain of the synchronous rectifier Q2 is almost equal to the output voltage Vo. At this time, since the first control signal GT_PSR and the second control signal GT_SR are both in a low level state for a certain period of time, the voltage amplitude of the output voltage Vo and the voltage VDS_S across the source and drain of the synchronous rectifier Q2 begin to gradually decrease. At this time, by detecting the voltage amplitude of the voltage VDS_S at the power terminals of the source and drain of the synchronous rectifier Q2, at time t6, when the voltage amplitude of the voltage VDS_S is less than or equal to the first threshold SW _TRIGGER When the drive control module 20 starts to output the third control signal GT_DY with the first frequency, during the period from time T6 to time t7, the third control signal GT_DY is at a high level, the second transistor Q3 is turned on, and the output voltage Vo is connected to the secondary winding N S , the second transistor Q3 and the first resistor R4 to the reference ground to form a conduction loop, and then again in the auxiliary winding N A The induced voltage is formed at both ends, and the voltage on the VS pin of the controller U1 rises. After sensing the voltage signal exceeding the threshold (such as 600mv), the controller U1 is triggered at time t7 to start providing the first control signal GT_PSR, thereby controlling the primary winding N P To the secondary winding N S The power / energy is transmitted so that the voltage amplitude of the output voltage Vo starts to increase (eg, at time t8 ), thereby preventing the output voltage Vo from dropping even lower.

[0052] It can be understood that in this embodiment, a corresponding first detection unit is provided in the drive control module 20 (such as in the drive control unit 21 of the drive control module 20), and the first detection unit is used to detect the difference between the voltage VDS_S and the first threshold SW after time t5. _TRIGGER Compare the voltage amplitudes and when the voltage amplitude of the voltage VDS_S is less than or equal to the first threshold SW _TRIGGER The corresponding control signal is output to the control signal generator 211, thereby triggering the control signal generator 211 to generate the third control signal GT_DY.

[0053] In the present disclosure, the first threshold is a preset fixed value, or the first threshold is adaptively adjusted following the voltage VDS_S at the two power terminals of the synchronous rectifier. When the first threshold is adaptively adjusted following the voltage VDS_S at the two power terminals of the synchronous rectifier, the drive control module 20 further includes: a sampling filter holding unit 23 and a ratio adjustment unit 24. The sampling filter holding unit 23 and the secondary winding N SThe proportional adjustment unit 24 is connected to the sampling filter holding unit 23 and the driving control unit 21 respectively, and is used to obtain the first threshold value SW according to the average value Vavg of the voltage at the two power ends of the synchronous rectifier and the preset proportional coefficient. _TRIGGER Among them, the first threshold SW _TRIGGER It is the product of the average value Vavg and a preset proportionality coefficient, where the preset proportionality coefficient is denoted as K%, where K is greater than or equal to 80 and less than 100.

[0054] Then, the driving control unit 21 (in this embodiment, if the first detection unit is set in the driving control unit 21, then the first detection unit) receives the voltage VDS_S at both power ends of the synchronous rectifier tube sampled by the sampling unit 22 and the corresponding first threshold SW _TRIGGER After the voltage amplitude comparison is performed, a corresponding control signal is output according to the comparison result to the control signal generator 211. When the output voltage fluctuates greatly and the gap from the first threshold is also large, since the corresponding comparison threshold is provided for the output voltage according to different level states, the dynamic response speed can be accelerated to prevent the output voltage from dropping too much.

[0055] In another embodiment of the present disclosure, reference Figure 4b ,in, Figure 4b and Figure 4a The similarities in Figure 4a The description of the embodiment is for comprehension, and will not be repeated here. The difference is that, in the present embodiment, the target parameter of the voltage VDS_S at the two power ends of the synchronous rectifier is the falling slope of the voltage VDS_S at the two power ends of the synchronous rectifier, and the preset condition to be satisfied is that the falling slope of the voltage VDS_S at the two power ends of the synchronous rectifier is greater than the second threshold. Based on this, a corresponding second detection unit is provided in the drive control module 20, and the second detection unit is used to detect the falling slope of the amplitude of the voltage VDS_S (such as dv / dt), and output a corresponding control signal to the control signal generator 211 when the falling slope is greater than the second threshold VT1, thereby triggering the control signal generator 211 to generate a third control signal GT_DY. With the same principle as above, the second threshold is a preset fixed value, or the second threshold is adaptively adjusted following the falling slope of the voltage at the two power ends of the synchronous rectifier.

[0056] In summary, the drive control module 20 further includes: a timing unit. The timing unit is connected to the drive control unit 21, and is used to re-time each time a rising edge of the second control signal GT_SR is detected, and when the timing value reaches a third threshold (for example Figure 4a and Figure 4bThe drive control module 20 is triggered at the time t5 in the figure to detect the target parameter of the voltage VDS_S at the two power terminals of the synchronous rectifier Q2. In this way, the accuracy and reliability of the detection of the voltage VDS_S can be improved, and the false triggering of the third control signal during the normal working time of other drivers can be avoided.

[0057] It should be understood that in Figure 4a and Figure 4b The third threshold T identified in D The frequency of the third control signal GT_DY is 55us, the frequency of the third control signal GT_DY is 30kHz, and the voltage Vs is 600mV, which are only exemplary embodiments of the present disclosure for auxiliary explanation, and are not intended to limit the content of the present disclosure. At the same time, it should be noted that the frequency of the third control signal GT_DY and the frequency of the first control signal GT-PSR triggered after the output voltage Vo drops should be correspondingly less than the initial frequency of the first control signal GT_PSR, that is, the normal driving frequency. Therefore, the technical solution of the present disclosure will not affect the normal operation of the switch-type regulating driver.

[0058] Furthermore, in this embodiment, the primary winding N of the transformer TR P A second resistor R1, a first capacitor C2 and a first diode D1 are also provided between the same-name end and the opposite-name end of the primary winding N. The second resistor R1 and the first capacitor C2 are connected in parallel to each other and then connected to the primary winding N. P The other end of the diode D1 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the primary winding N P In this way, the primary winding N P The leakage current is reduced, thus improving the transformer performance.

[0059] Figure 5 A flow chart of a switch-type regulating driving method provided according to an embodiment of the present disclosure is shown.

[0060] like Figure 5 As shown, in this embodiment, the switch type regulation driving method can be applied to Figures 2 to 3 In the switch type regulating driver described in the embodiment, it includes executing steps S1 to S3.

[0061] Specifically, in step S1, a first current pulse is made to flow through the primary winding of the transformer, and a second current pulse is formed on the secondary winding of the transformer based on a first control signal.

[0062] refer to Figure 2 , a first current pulse is generated based on the input voltage Vin, and the controller U1 outputs a high-level first control signal GT_PSR to control the first transistor Q1 to turn on, thereby making the first current pulse pass through the primary winding N of the transformer TR P, the first transistor Q1 and the current sensing resistor Rs form a current active path, thereby the secondary winding N of the transformer TR S The second current pulse is induced.

[0063] In step S2, the second control signal is input to the control terminal of the synchronous rectifier, and the synchronous rectifier rectifies the second current pulse to form an output voltage.

[0064] In the secondary winding N S After the second current pulse is induced, the driving control module 20 outputs a second control signal GT_SR to control the intermittent on and off of the synchronous rectifier Q2. After the second current pulse is synchronously rectified, an output voltage Vo is formed at both ends of the output capacitor Co.

[0065] In step S3, target parameters of the voltages at two power terminals of the synchronous rectifier are detected, and when it is detected that the target parameters of the voltages at two power terminals of the synchronous rectifier meet preset conditions, the controller is triggered to control the primary winding to transfer power to the secondary winding.

[0066] In one embodiment of the present disclosure, target parameters of the voltage at two power ends of the synchronous rectifier are detected, and when it is detected that the target parameters of the voltage at two power ends of the synchronous rectifier meet preset conditions, the trigger controller controls the primary winding to transfer power to the secondary winding, including: detecting the voltage amplitude of the voltage at two power ends of the synchronous rectifier, and when it is detected that the voltage amplitude of the voltage at two power ends of the synchronous rectifier is less than or equal to a first threshold value, the trigger controller controls the primary winding to transfer power to the secondary winding.

[0067] In another embodiment of the present disclosure, target parameters of the voltage at two power ends of the synchronous rectifier are detected, and when it is detected that the target parameters of the voltage at two power ends of the synchronous rectifier meet preset conditions, the trigger controller controls the primary winding to transfer power to the secondary winding, including: detecting the falling slope of the voltage at two power ends of the synchronous rectifier, and when it is detected that the falling slope of the voltage at two power ends of the synchronous rectifier is greater than a second threshold, the trigger controller controls the primary winding to transfer power to the secondary winding.

[0068] Further, the trigger controller controls the primary winding to transfer power to the secondary winding, including: generating a third control signal with a first frequency, forming a third current pulse on the secondary winding based on the third control signal; forming an induced current on the auxiliary winding of the transformer based on the third current pulse, and forming a trigger signal to the controller based on the induced current; the trigger signal triggers the controller to control the current loop where the primary winding is located to conduct, and transfer power to the secondary winding. In this embodiment, reference Figure 2 and Figure 3When it is detected that the target parameters of the voltages at the two power terminals of the synchronous rectifier meet the preset conditions, the driving control unit 21 is triggered to generate a third control signal GT_DY with a first frequency to the second transistor Q3, and the second transistor Q3 is intermittently turned on / off, thereby generating a third control signal GT_DY at the auxiliary winding N A An induced voltage is formed at both ends. After the VS pin of the controller U1 senses the corresponding voltage signal, the controller U1 is triggered to start providing the first control signal GT_PSR, thereby controlling the primary winding N P To the secondary winding N S The power / energy is transmitted, so that the voltage amplitude of the output voltage Vo starts to increase, and the output voltage Vo is prevented from dropping to a lower level.

[0069] In the present disclosure, before detecting the target parameters of the voltage at the two power terminals of the synchronous rectifier, it also includes: detecting the rising edge of the second control signal, retiming after each detection of the rising edge of the second control signal (i.e., clearing the current timing value and starting to retiming); triggering the detection of the target parameters of the voltage at the two power terminals of the synchronous rectifier when the timing value reaches the third threshold. It is understandable that, it is also possible to calculate the difference between the timing value at the current moment and the timing value at the previous rising edge moment each time after the rising edge of the second control signal is detected, determine whether the difference is over and clear the current timing value, start retiming, and trigger the detection of the target parameters of the voltage at the two power terminals of the synchronous rectifier when the difference reaches the third threshold.

[0070] Further, the drive control module 20 stops outputting the third control signal after detecting that the driver resumes normal operation.

[0071] The present disclosure also provides a switching power supply, wherein the switching power supply includes a corresponding Figures 2 to 3 The switching regulator driver described in .

[0072] In summary, the present invention is provided with a drive control module at the secondary winding end of the driver. The drive control module detects the target parameters of the voltage at the two power ends of the synchronous rectifier tube, thereby achieving the purpose of indirectly sampling the output voltage information, thereby matching with the previous chip to realize the function of dynamic acceleration and avoid output voltage drop. At the same time, it can also reduce the dependence on output pins and even save output pins.

[0073] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0074] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A switch type regulating driver, wherein: include: A transformer comprising a primary winding, a secondary winding and an auxiliary winding; a first transistor having a first power terminal connected to the same-name terminal of the primary winding and a second power terminal connected to a reference ground via a current sensing resistor; A controller, connected to the control terminal and the second power terminal of the first transistor respectively, and the controller generates a first control signal to the control terminal of the first transistor; A synchronous rectifier tube connected between the opposite-name end of the secondary winding and a reference ground; The drive control module is connected to the control end of the synchronous rectifier tube and the opposite end of the secondary winding respectively. Among them, the drive control module is used to detect the target parameters of the voltage at the two power ends of the synchronous rectifier when the synchronous rectifier disconnects the conductive path between the opposite end of the secondary winding and the reference ground, and when it is detected that the target parameters of the voltage at the two power ends of the synchronous rectifier meet the preset conditions, generate a third control signal with a first frequency, form a third current pulse on the secondary winding based on the third control signal, form an induced current on the auxiliary winding based on the third current pulse, and form a trigger signal to the controller based on the induced current, triggering the controller to control the switching action of the first transistor so that the primary winding transfers power to the secondary winding.

2. The switching regulator driver according to claim 1, wherein: The voltage signal at both ends of the auxiliary winding is divided by a voltage dividing resistor to generate a voltage dividing signal which is transmitted to the controller. The controller controls the switching action of the first transistor according to information of the voltage division signal.

3. The switch type regulating driver according to claim 2, wherein: The drive control module comprises: A second transistor and a first resistor, wherein the second transistor and the first resistor are sequentially connected in series between the opposite-name end of the secondary winding and a reference ground; A sampling unit, connected to the opposite-name end of the secondary winding, for sampling the voltage between the two power ends of the synchronous rectifier to obtain the voltage between the two power ends of the synchronous rectifier; A driving control unit is respectively connected to the sampling unit, the control end of the synchronous rectifier and the control end of the second transistor, and is used to provide a second control signal to the synchronous rectifier, and to provide a third control signal to the second transistor according to the voltages at the two power ends of the synchronous rectifier.

4. The switch type regulating driver according to claim 3, wherein: The drive control unit comprises: a control signal generator, comprising a first output terminal for providing the second control signal, and a second output terminal for providing the third control signal, and A driver receives the second control signal to generate a driving signal to drive the synchronous rectifier.

5. The switch type regulating driver according to claim 4, wherein: The target parameter of the voltage at the two power ends of the synchronous rectifier is the voltage amplitude of the voltage at the two power ends of the synchronous rectifier, and the preset condition is that the voltage amplitude is less than or equal to the first threshold.

6. The switch-type regulating driver according to claim 5, wherein: The first threshold is a preset fixed value; or The first threshold is adaptively adjusted following the voltages at two power terminals of the synchronous rectifier.

7. The switching regulator driver according to claim 6, wherein: When the first threshold is adaptively adjusted following the voltage at the two power terminals of the synchronous rectifier, the drive control module further includes: A sampling, filtering and holding unit connected to the opposite-name end of the secondary winding, for sampling and filtering the voltage between the two power ends of the synchronous rectifier tube to obtain an average value of the voltage between the two power ends of the synchronous rectifier tube; a proportional adjustment unit, connected to the sampling, filtering and holding unit and the driving control unit respectively, for obtaining the first threshold value according to an average value of the voltages at the two power terminals of the synchronous rectifier and a preset proportional coefficient, The first threshold is the product of the average value and the preset proportional coefficient, and the preset proportional coefficient is denoted as K%, where K is greater than or equal to 80 and less than 100.

8. The switch-type regulating driver according to claim 1, wherein: The target parameter of the voltage at the two power ends of the synchronous rectifier is the falling slope of the voltage at the two power ends of the synchronous rectifier, and the preset condition is that the falling slope is greater than a second threshold.

9. The switch type regulating driver according to claim 3, wherein: The drive control module also includes: A timing unit is connected to the drive control unit, and is used to re-time each time a rising edge of the second control signal is detected, and trigger the drive control module to detect the target parameters of the voltage at the two power terminals of the synchronous rectifier when the timing value reaches a third threshold.

10. A switch type regulation driving method, wherein: The switch type regulating driving method can be applied to the switch type regulating driver according to any one of claims 1 to 9, and the method comprises: Allowing the first current signal to flow through the primary winding of the transformer, and forming a second current signal on the secondary winding of the transformer based on the first control signal; The second control signal is input to the control end of the synchronous rectifier, and the synchronous rectifier adjusts the second current signal to form an output signal. Wherein, the method further comprises: Detecting target parameters of voltages at two power terminals of the synchronous rectifier, and when detecting that the target parameters of voltages at two power terminals of the synchronous rectifier meet preset conditions, controlling the primary winding to transfer power to the secondary winding.

11. The switching type regulation driving method according to claim 10, wherein: Detecting target parameters of voltages at two power terminals of the synchronous rectifier, and when detecting that the target parameters of voltages at two power terminals of the synchronous rectifier meet preset conditions, triggering a controller to control the primary winding to transfer power to the secondary winding includes: The voltage amplitude of the voltage at the two power terminals of the synchronous rectifier is detected, and when it is detected that the voltage amplitude of the voltage at the two power terminals of the synchronous rectifier is less than or equal to a first threshold, the primary winding is controlled to transfer power to the secondary winding.

12. The switching type regulation driving method according to claim 10, wherein: Detecting target parameters of voltages at two power terminals of the synchronous rectifier, and controlling the primary winding to transfer power to the secondary winding when detecting that the target parameters of voltages at two power terminals of the synchronous rectifier meet preset conditions includes: The falling slope of the voltage at the two power terminals of the synchronous rectifier is detected, and when it is detected that the falling slope of the voltage at the two power terminals of the synchronous rectifier is greater than a second threshold, the primary winding is controlled to transfer power to the secondary winding.

13. The switch type regulation driving method according to any one of claims 10 to 12, wherein: Controlling the primary winding to transfer power to the secondary winding includes: generating a third control signal having a first frequency, and forming a third current signal on the secondary winding based on the third control signal; Based on the third current signal, an induced current is formed on the auxiliary winding of the transformer, and based on the induced current, a trigger signal is formed to the controller; The trigger signal triggers the controller to control the current loop where the primary winding is located to be turned on, so as to transmit power to the secondary winding.

14. The switching type regulating driving method according to any one of claims 10 to 12, wherein: Before detecting the target parameters of the voltages at the two power terminals of the synchronous rectifier, the method further includes: detecting a rising edge of the second control signal, and retiming each time a rising edge of the second control signal is detected; When the timing value reaches the third threshold, it is triggered to detect the target parameters of the voltages at the two power terminals of the synchronous rectifier.

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