Power tube driving circuit and chip

Abstract

The embodiment of the utility model discloses a power tube driving circuit and a chip, which are used for driving a power tube, and comprise a comparison module of which the first input end is connected with a first threshold voltage end, the second input end is connected with a second threshold voltage end, and the third input end is connected with a grid voltage end; comprising a first current branch, a second current branch and a third current branch, and the output end of each current branch is connected with the grid voltage end; the input end of the current control module is connected with the output end of the comparison module, the output end of the current control module is connected with the controlled end of each current branch, and the current control module controls the current output module to sequentially output the first current, the second current and the third current in the starting process of the power tube. In the starting process of the power tube, by controlling the current branches, it can be guaranteed that the valley bottom locking position does not deviate, the starting period is basically unchanged, electromagnetic interference is obviously reduced, and the defects existing in the prior art are overcome.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, and in particular to a power tube driving circuit and a chip. Background Art

[0002] In the switching power supply control circuit, it is necessary to drive the power tube so that the switching power supply can work normally. In the process of turning on the power tube, the gate voltage is as follows: Figure 1 As shown, the rising line represents the gate voltage of the power tube, and the falling line represents the drain-source voltage of the power tube. In the stage from t0 to t1, the gate voltage gradually rises, the power tube is basically in the cut-off state, and the drain-source voltage remains basically unchanged. In the stage from t1 to t2, the gate voltage enters the Miller platform, the power tube is gradually turned on, and the drain-source voltage drops rapidly. In the stage from t2 to t3, the gate voltage gradually rises again until it reaches a basically stable state, and the drain-source voltage remains basically unchanged; in the above stage from t0 to t3, the gate current remains basically unchanged. It is found through actual measurement that in the stage (t2 to t3) where the drain-source voltage of the power tube drops rapidly, a large electromagnetic interference will be generated. In order to improve the above problem, the stage from t0 to t3 is usually lengthened. The effect of reducing electromagnetic interference in this way is not obvious, and the time period of the power tube opening process will be too long. Since the stage from t0 to t3 needs to be lengthened, the valley position of the drain-source voltage of the power tube will be offset, resulting in the inability to lock the valley position according to the original scheme, which seriously affects the power consumption of the power tube. Utility Model Content

[0003] The purpose of the embodiment of the utility model is to provide a power tube driving circuit and chip to solve the above problems. The embodiment of the utility model achieves the above purpose through the following technical solutions.

[0004] The embodiment of the utility model provides a power tube driving circuit for driving the power tube, including: a comparison module, a first input end of which is connected to a first threshold voltage end, a second input end of which is connected to a second threshold voltage end, and a third input end of which is connected to a gate voltage end; a current output module including a first current branch, a second current branch, and a third current branch, and the output end of each current branch is respectively connected to the gate voltage end; a current control module, an input end of which is connected to an output end of the comparison module, and an output end of which is respectively connected to a controlled end of the first current branch, a controlled end of the second current branch, and a controlled end of the third current branch, and during the power tube startup process, the current control module controls the current output module to output a first current, a second current, and a third current in sequence.

[0005] In some embodiments, when the comparison module outputs a signal indicating that the gate voltage terminal voltage is less than the first threshold voltage terminal voltage, the current output module outputs a first current; when the comparison module outputs a signal indicating that the gate voltage terminal voltage is greater than the second threshold voltage terminal voltage, the current output module outputs a third current.

[0006] In some embodiments, the first current branch includes a first switch tube and a first current source connected to the gate voltage end in sequence, and the controlled end of the first switch tube is connected to the current control module; the second current branch includes a second switch tube and a second current source connected to the gate voltage end in sequence, and the controlled end of the second switch tube is connected to the current control module; the third current branch includes a third switch tube and a third current source connected to the gate voltage end in sequence, and the controlled end of the third switch tube is connected to the current control module.

[0007] In some embodiments, the first current branch includes a fourth switch tube connected between the first voltage terminal and the gate voltage terminal, and the controlled end of the fourth switch tube is connected to the current control module; the second current branch includes a fifth switch tube connected between the second voltage terminal and the gate voltage terminal, and the controlled end of the fifth switch tube is connected to the current control module; the third current branch includes a sixth switch tube connected between the third voltage terminal and the gate voltage terminal, and the controlled end of the sixth switch tube is connected to the current control module.

[0008] In some embodiments, the sum of the currents output by the first current branch and the second current branch is used as the first current; and the sum of the currents output by the second current branch and the third current branch is used as the third current.

[0009] In some embodiments, the comparison module includes a comparison unit and a switching switch, the first end of the switching switch is connected to the first threshold voltage end, the second end of the switching switch is connected to the second threshold voltage end, the first input end of the comparison unit is connected to the gate voltage end, the second input end of the comparison unit is connected to the third end of the switching switch, and the output end of the comparison unit is connected to the current control module.

[0010] In some embodiments, the current control module is further configured to control the current output module to output the third current, the second current, and the first current in sequence during the power tube shutdown process.

[0011] In some embodiments, a resistor is connected between the gate voltage terminal and the gate of the power tube.

[0012] In some embodiments, the third current is greater than the first current.

[0013] An embodiment of the utility model further provides a power tube driver chip, and the power tube driver chip includes the power tube driver circuit provided by any of the above embodiments.

[0014] The power tube driving circuit and chip provided in this embodiment include a comparison module, a current output module and a current control module. The power tube opening cycle can be basically unchanged. During the power tube opening process, the time for the gate voltage of the power tube to reach the first threshold voltage is shortened, the time for the gate voltage of the power tube to change from the first threshold voltage to the second threshold voltage is lengthened, and the time for the gate voltage of the power tube to reach the stable voltage in the fully on state from the second threshold voltage is shortened. By controlling the first current branch, the second current branch and the third current branch, it can be ensured that the valley bottom locking position will not be offset, the opening cycle is basically unchanged, and the electromagnetic interference is significantly reduced, which solves the defects of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is a voltage schematic diagram of a power tube driving process in the prior art;

[0017] Figure 2 It is another voltage schematic diagram in the power tube driving process in the prior art;

[0018] Figure 3 This is a schematic diagram of a structure of a power tube driving circuit provided by an embodiment of the utility model;

[0019] Figure 4 This is a voltage schematic diagram of the power tube driving process provided by the embodiment of the utility model;

[0020] Figure 5 This is another structural schematic diagram of the power tube driving circuit provided by an embodiment of the utility model;

[0021] Figure 6 This is another structural schematic diagram of the power tube driving circuit provided by the embodiment of the utility model;

[0022] Figure 7 This is another structural schematic diagram of the power tube driving circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In order to more clearly understand the technical solution of the embodiment of the utility model, the prior art described in the background technology is further explained below. In the prior art, Figure 2 As shown, the method of lengthening the opening cycle will cause the original valley bottom locking position to shift (a), resulting in an increase in the power consumption of the power tube. In addition, the t0 to t1 stage and the t2 to t3 stage account for a large proportion of the entire opening cycle, and the t1 to t2 stage is relatively small, so that the duration of the t1 to t2 stage in the lengthened opening cycle is still relatively low, and the actual duration of the power tube being fully turned on does not achieve the expected effect, affecting the circuit performance. Based on this, the inventor of the present utility model proposes a power tube drive circuit and chip of an embodiment of the present utility model to solve the problems existing in the power tube drive in the prior art. A power tube drive circuit and chip provided by the present utility model are described in detail below.

[0025] like Figure 3 As shown, a power tube driving circuit provided in this embodiment is used to drive a power tube M, including: a comparison module 11, a first input terminal of which is connected to a first threshold voltage terminal, a second input terminal of which is connected to a second threshold voltage terminal, and a third input terminal of which is connected to a gate voltage terminal; a current output module 12 including a first current branch 121, a second current branch 122, and a third current branch 123, and the output terminal of each current branch is respectively connected to the gate voltage terminal; a current control module 13, an input terminal of which is connected to an output terminal of the comparison module 11, and an output terminal of which is respectively connected to a controlled terminal of the first current branch 121, a controlled terminal of the second current branch 122, and a controlled terminal of the third current branch 123, and when the power tube M is turned on, the current control module 13 controls the current output module 12 to output a first current, a second current, and a third current in sequence.

[0026] It should be noted that the power tube driving circuit provided in this embodiment is not limited to applications such as Figure 3 The power tube M of the switching power supply shown in the figure can also be applied to a full-bridge switching circuit, a symmetrical half-bridge switching circuit, an asymmetrical half-bridge switching circuit, a flyback switching circuit, a forward switching circuit, etc. The power tube M can be as follows: Figure 3 N-type power tube shown.

[0027] In this embodiment, the first threshold voltage terminal can be regarded as a node whose voltage is the first threshold voltage Vth1. The node can provide a signal representing the size of the first threshold voltage Vth1. When connected to the first threshold voltage terminal, it means that the signal of the first threshold voltage Vth1 can be obtained; the second threshold voltage terminal is the same as the gate voltage terminal, and will not be repeated here.

[0028] In this embodiment, the comparison module 11 may include a first comparator OP1 and a second comparator OP2, wherein a first input terminal of the first comparator OP1 is connected to a first threshold voltage terminal, a second input terminal of the first comparator OP1 is connected to a gate voltage terminal, and an output terminal of the first comparator OP1 is connected to a current control module 13; a first input terminal of the second comparator OP2 is connected to a second threshold voltage terminal, a second input terminal of the first comparator OP1 is connected to a gate voltage terminal, and an output terminal of the first comparator OP1 is connected to the current control module 13. The first comparator OP1 may output a comparison result representing the comparison between the first threshold voltage Vth1 and the gate voltage, and the second comparator OP2 may output a comparison result representing the comparison between the second threshold voltage Vth2 and the gate voltage.

[0029] In this embodiment, the first current branch 121, the second current branch 122, and the third current branch 123 can each output a corresponding current. Among them, the first current branch 121, the second current branch 122, and the third current branch 123 can respectively output the first current, the second current, and the third current. At this time, during the power tube M startup process, only one current branch is turned on at a time, and the other current branches are turned off.

[0030] In addition, the sum of the currents output by the first current branch 121 and the second current branch 122 may be used as the first current, the current output by the second current branch 122 may be used as the second current, and the sum of the currents output by the second current branch 122 and the third current branch 123 may be used as the third current. In this case, during the power tube M startup process, the second current branch 122 is always turned on, which can relatively reduce the currents required to be set for the first current branch 121 and the third current branch 123.

[0031] In this embodiment, during the power tube M startup process, the current control module 13 controls the first current branch 121, the second current branch 122, and the third current branch 123 to sequentially output the first current, the second current, and the third current, and the first current are both greater than the second current. Figure 4 As shown, at this time, the period from t0 to t1 is shortened, the period from t1 to t2 is lengthened, the period from t2 to t3 is shortened, and the duration from t10 to t1 can remain basically unchanged, but the drain-source voltage drop speed of the power tube M is significantly slowed down.

[0032] Therefore, in this embodiment, the opening period of the power tube M can be basically kept unchanged. During the opening process of the power tube M, the time for the gate voltage of the power tube M to reach the first threshold voltage Vth1 is shortened, the time for the gate voltage of the power tube M to change from the first threshold voltage Vth1 to the second threshold voltage Vth2 is lengthened, and the time for the gate voltage of the power tube M to reach the stable voltage in the fully-on state from the second threshold voltage Vth2 is shortened. By controlling the first current branch 121, the second current branch 122, and the third current branch 123, it can be ensured that the valley bottom locking position will not be offset, the opening period is basically unchanged, and the electromagnetic interference is significantly reduced, thereby solving the defects of the prior art.

[0033] Further, in some embodiments, when the comparison module 11 outputs a signal indicating that the gate voltage terminal voltage is less than the first threshold voltage terminal voltage, each current branch can output a first current; when the comparison module 11 outputs a signal indicating that the gate voltage terminal voltage is greater than the second threshold voltage terminal voltage, the current output module 12 outputs a third current. In addition, when the comparison module 11 outputs a signal indicating that the gate voltage terminal voltage is between the first threshold voltage Vth1 and the second threshold voltage Vth2, the current output module 12 can output a second current.

[0034] Furthermore, in some embodiments, Figure 4 As shown, the third current is greater than the first current, thereby shortening the period from t2 to t3.

[0035] Furthermore, in some embodiments, Figure 5 As shown, the first current branch 121 may include a first switch tube N1 and a first current source Ia connected in sequence to the gate voltage end, and the controlled end of the first switch tube N1 may be connected to the current control module 13; the second current branch 122 may include a second switch tube N2 and a second current source Ib connected in sequence to the gate voltage end, and the controlled end of the second switch tube N2 may be connected to the current control module 13; the third current branch 123 may include a third switch tube N3 and a third current source Ic connected in sequence to the gate voltage end, and the controlled end of the third switch tube N3 may be connected to the current control module 13.

[0036] In this embodiment, the controlled end of the first switch tube N1, the controlled end of the second switch tube N2, and the controlled end of the third switch tube N3 can be the gate of each switch tube, and the current control module 13 sends a control signal to control the on-off state of each switch tube. There is no specific restriction on the type of each switch tube. Among them, the size of the first current source Ia can be the first current, the size of the second current source Ib can be the second current, and the size of the second current source Ib can be the first current; the sum of the first current source Ia and the second current source Ib can be the first current, the size of the second current source Ib can be the second current, and the sum of the second current source Ib and the third current source Ic can be the first current.

[0037] Furthermore, in some embodiments, Figure 6 As shown, the first current branch 121 may include a fourth switch tube N4 connected between the first voltage terminal and the gate voltage terminal, and the controlled end of the fourth switch tube N4 may be connected to the current control module 13; the second current branch 122 may include a fifth switch tube N5 connected between the second voltage terminal and the gate voltage terminal, and the controlled end of the fifth switch tube N5 may be connected to the current control module 13; the third current branch 123 may include a sixth switch tube N6 connected between the third voltage terminal and the gate voltage terminal, and the controlled end of the sixth switch tube N6 may be connected to the current control module 13.

[0038] In this embodiment, the current output by the current output module 12 can be controlled by voltage control, and the voltages of the first voltage terminal, the second voltage terminal, and the third voltage terminal can be configured based on actual needs.

[0039] Further, in some embodiments, the sum of the currents output by the first current branch 121 and the second current branch 122 can be used as the first current; the sum of the currents output by the second current branch 122 and the third current branch 123 can be used as the third current.

[0040] Furthermore, in some embodiments, Figure 7 As shown, the comparison module 11 may include a comparison unit OP3 and a switching switch K, wherein the first end of the switching switch K is connected to the first threshold voltage end, the second end of the switching switch K is connected to the second threshold voltage end, the first input end of the comparison unit OP3 is connected to the gate voltage end, the second input end of the comparison unit OP3 is connected to the third end of the switching switch K, and the output end of the comparison unit OP3 is connected to the current control module 13.

[0041] In this embodiment, when the power tube M is turned on, the first threshold voltage terminal can be connected to the second input terminal of the comparison unit OP3 by switching the switch K, and then the second threshold voltage terminal can be connected to the second input terminal of the comparison unit OP3 by switching the switch K.

[0042] It should be noted that in the power tube driving circuit provided in this embodiment, the level of the pulse signal can be used to confirm whether the power tube M is in the on process. The level of the pulse signal can also be used to confirm whether the power tube M is in the off process.

[0043] Furthermore, in some embodiments, the current control module 13 may also be configured to control the current output module 12 to output the third current, the second current, and the first current in sequence when the power tube M is turned off.

[0044] In this embodiment, during the shutdown process of the power tube M, the current control module 13 outputs the third current by controlling each current branch, and the time for the gate voltage of the power tube M to reach the second threshold voltage Vth2 is shortened. The current control module 13 outputs the second current by controlling each current branch, and the time for the gate voltage of the power tube M to change from the second threshold voltage Vth2 to the first threshold voltage Vth1 is lengthened. The current control module 13 outputs the first current by controlling each current branch, and the time for the gate voltage of the power tube M to reach the stable voltage in the cut-off state from the first threshold voltage Vth1 is shortened. Electromagnetic interference can be significantly reduced while keeping the shutdown period basically unchanged.

[0045] Regarding the manner in which the current control module 13 controls each current branch to output the first current, the second current, and the third current during the shutdown process of the power tube M, the manner is similar to that during the startup process of the power tube M, and will not be repeated here.

[0046] Furthermore, in some embodiments, a resistor is connected between the gate voltage terminal and the gate of the power tube M. In this embodiment, the resistor can prevent excessive current and protect components in the circuit.

[0047] An embodiment of the utility model further provides a power tube driver chip, and the power tube driver chip includes the power tube driver circuit provided by any of the above embodiments.

[0048] Since the circuit structure and working mode of the power tube driving circuit in the power tube driving chip in this embodiment are the same as those of the power tube driving circuit in the previous embodiment, they will not be described in detail here.

[0049] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A power tube driving circuit, characterized in that: Used to drive power tubes, including: A comparison module, wherein a first input terminal is connected to the first threshold voltage terminal, a second input terminal is connected to the second threshold voltage terminal, and a third input terminal is connected to the gate voltage terminal; A current output module comprising a first current branch, a second current branch and a third current branch, wherein the output end of each current branch is respectively connected to the gate voltage end; A current control module, whose input end is connected to the output end of the comparison module, and whose output end is respectively connected to the controlled end of the first current branch, the controlled end of the second current branch, and the controlled end of the third current branch. During the power tube startup process, the current control module controls the current output module to output the first current, the second current, and the third current in sequence.

2. The power tube driving circuit according to claim 1, characterized in that: When the comparison module outputs a signal indicating that the gate voltage terminal voltage is less than the first threshold voltage terminal voltage, the current output module outputs the first current; when the comparison module outputs a signal indicating that the gate voltage terminal voltage is greater than the second threshold voltage terminal voltage, the current output module outputs the third current.

3. The power tube driving circuit according to claim 1, characterized in that: The first current branch includes a first switch tube and a first current source connected to the gate voltage end in sequence, and a controlled end of the first switch tube is connected to the current control module; the second current branch includes a second switch tube and a second current source connected to the gate voltage end in sequence, and a controlled end of the second switch tube is connected to the current control module; the third current branch includes a third switch tube and a third current source connected to the gate voltage end in sequence, and a controlled end of the third switch tube is connected to the current control module.

4. The power tube driving circuit according to claim 1, characterized in that: The first current branch includes a fourth switch tube connected between the first voltage terminal and the gate voltage terminal, and the controlled end of the fourth switch tube is connected to the current control module; the second current branch includes a fifth switch tube connected between the second voltage terminal and the gate voltage terminal, and the controlled end of the fifth switch tube is connected to the current control module; the third current branch includes a sixth switch tube connected between the third voltage terminal and the gate voltage terminal, and the controlled end of the sixth switch tube is connected to the current control module.

5. The power tube driving circuit according to claim 1, characterized in that: The sum of the currents output by the first current branch and the second current branch is used as the first current; the sum of the currents output by the second current branch and the third current branch is used as the third current.

6. The power tube driving circuit according to claim 1, characterized in that: The comparison module includes a comparison unit and a switching switch, the first end of the switching switch is connected to the first threshold voltage end, the second end of the switching switch is connected to the second threshold voltage end, the first input end of the comparison unit is connected to the gate voltage end, the second input end of the comparison unit is connected to the third end of the switching switch, and the output end of the comparison unit is connected to the current control module.

7. The power tube driving circuit according to any one of claims 1 to 6, characterized in that: The current control module is further configured to control the current output module to sequentially output the third current, the second current, and the first current during the shutdown process of the power tube.

8. The power tube driving circuit according to any one of claims 1 to 6, characterized in that: A resistor is connected between the gate voltage terminal and the gate of the power tube.

9. The power tube driving circuit according to any one of claims 1 to 6, characterized in that: The third current is greater than the first current.

10. A power tube driver chip, characterized in that: The invention comprises a power tube driving circuit as claimed in any one of claims 1 to 9.

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