CN115706505A - Power switching tube driving circuit and method - Google Patents
Power switching tube driving circuit and method Download PDFInfo
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- CN115706505A CN115706505A CN202110923548.3A CN202110923548A CN115706505A CN 115706505 A CN115706505 A CN 115706505A CN 202110923548 A CN202110923548 A CN 202110923548A CN 115706505 A CN115706505 A CN 115706505A
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Abstract
The invention discloses a power switch tube driving circuit and a method, when a power switch tube is conducted, a charging module charges by using current output by a current sequence module to generate voltage to be provided for a grid electrode of a source electrode following switch, and controls the current sequence module to generate variable charging current in the charging process, so that the grid electrode voltage of the power switch tube quickly rises to be close to a starting threshold value and then slowly rises and is kept at the starting threshold value; when the power switch tube needs to be turned off, the switch tube sequence module is conducted and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is quickly reduced to be close to the starting threshold value, slowly reduced to be zero after being slowly reduced to the starting threshold value, and then quickly reduced to be zero.
Description
Technical Field
The invention relates to the field of switching power supplies, in particular to a power switching tube driving circuit and a power switching tube driving method.
Background
As shown in fig. 1, the conventional MOS driving circuit includes a driving control circuit, switching transistors M1 and M2, and a power MOS transistor M0. The driving control circuit drives the power MOS tube M0 by controlling the switches K1 and K2 to open and close the switching tubes M1 and M2.
Referring to fig. 1 and 2, vgate and VD in fig. 2 represent the gate and drain voltages of M0, respectively, and R (on) _ M2 represents the equivalent resistance of M2. The conduction process of the power MOS tube M0 is as follows: k1 is low level, switch tube M1 switches on, K2 is low level, switch tube M2 cuts off, driving current flows in source electrode follower switch grid, power MOS pipe M0 grid charges through source electrode follower switch M1, power MOS pipe grid voltage rising is greater than power MOS pipe opening threshold voltage Vt0 (Vt 0 is power MOS pipe characteristic parameter), the MOS pipe switches on rapidly, power MOS pipe drain-source electrode current flows through Rs, rs voltage also increases thereupon. Since the power MOS transistor M0 is turned on rapidly, it is easy to cause large EMI interference, which results in a large overshoot at the initial stage of the source voltage (Vs voltage in the figure) of the power MOS transistor M0. The turn-off process of the power MOS transistor M0 is as follows: the driving module controls K1 to be high level, K2 to be low level, the switch tube M1 is cut off, the switch tube M2 is conducted, grid charges of the power MOS tube M0 are discharged to reference ground through the M2, therefore, the grid charges of the M0 are quickly discharged to the low level, the power MOS tube M0 is cut off, and as the grid charges of the power MOS tube M0 are discharged too fast, the drain voltage of the power MOS tube M0 rises too fast, and a large voltage change rate (dv/dt) exists, so that EMI interference is caused.
Disclosure of Invention
The present invention provides a power switch driving circuit and a method thereof, aiming at the above-mentioned disadvantage of the prior art that is easily caused by EMI interference.
The technical scheme adopted by the invention for solving the technical problem is as follows:
in one aspect, a power switch driving circuit is configured, and the driving circuit includes:
the grid voltage detection circuit is connected with the grid of the power switch tube and is used for detecting the grid voltage of the power switch tube in real time;
the drain electrode of the source electrode following switch is connected with a power supply, and the source electrode of the source electrode following switch is connected with the grid electrode of the power switch tube;
the charging module is connected between the grid of the source electrode following switch and the ground and used for charging by using the current output by the current sequence module to generate voltage to be supplied to the grid of the source electrode following switch;
the switching tube sequence module comprises a plurality of switching tubes connected in parallel, and the drain electrodes of the switching tubes are connected with the grid electrodes and the source electrodes of the power switching tubes and grounded;
the driving control circuit is respectively connected with the grid voltage detection circuit, the current sequence module, the grid of the source electrode following switch and the grid of the switch tube, when the power switch tube needs to be conducted, the driving control circuit controls the switch tubes of the switch tube sequence module to be completely turned off, and controls the current sequence module to generate variable charging current so that the grid voltage of the power switch tube quickly rises to be close to a starting threshold value of the power switch tube and then slowly rises and is kept at the starting threshold value; when the power switch tube needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero so that the source electrode follows the switch to be turned off, controls the switch tube sequence module to be turned on and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is quickly reduced to the turn-on threshold value when the grid voltage is quickly reduced to be close to the turn-on threshold value of the power switch tube, and then is quickly reduced to be zero.
Preferably, the controlling the current sequence module to generate a variable charging current includes:
the first stage is as follows: controlling the current sequence module to generate a first current so as to enable the grid voltage of the power switch tube to rise rapidly, and entering a second stage when the grid voltage of the power switch tube is detected to rise to be close to the starting threshold value;
and a second stage: controlling the current sequence module to generate a second current and start timing, wherein the second current is smaller than the first current so that the grid voltage of the power switch tube slowly rises at the stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a first preset time;
and a third stage: controlling the current sequence module to generate a third current and starting timing, wherein the third current is larger than the second current so that the gate voltage of the source follower switch rapidly rises to a limit voltage Vclamp of the charging module, the gate voltage of the power switch tube rises to Vclamp-Vgs along with the rise, vgs represents the voltage difference between the gate and the source when the source follower switch is turned on, and the fourth stage is started when the timing time reaches a second preset time;
a fourth stage: controlling the current sequence module to generate a fourth current that is less than the third current to maintain a gate voltage of the source follower switch at the limit voltage Vclamp.
Preferably, the controlling the switch tube sequence module to be turned on and generate a variable equivalent resistance includes:
the first stage is as follows: controlling the equivalent resistance of the switching tube sequence module to be a first equivalent resistance so as to enable the grid voltage of the power switching tube to be rapidly reduced until the grid voltage of the power switching tube is detected to be reduced to be close to the opening threshold value, and entering a second stage;
and a second stage: controlling the equivalent resistance of the switching tube sequence module to be a second equivalent resistance and starting timing, wherein the second equivalent resistance is larger than the first equivalent resistance so that the grid voltage of the power switching tube slowly drops at the stage and is kept at the opening threshold value, and entering a third stage when the timing time reaches a third preset time;
and a third stage: and controlling the equivalent resistance of the switching tube sequence module to be a third equivalent resistance, wherein the third equivalent resistance is smaller than the second equivalent resistance so as to rapidly reduce the grid voltage of the power switching tube to zero.
Preferably, the charging module includes a clamping voltage stabilizing diode and a charging capacitor, the charging capacitor is connected between the gate of the source follower switch and ground, the negative electrode of the clamping voltage stabilizing diode is connected with the gate of the source follower switch, and the positive electrode of the clamping voltage stabilizing diode is grounded.
Preferably, the driving circuit further comprises a pre-switch, the pre-switch is connected between the gate of the source follower switch and ground, and the control end of the pre-switch is connected with the driving control circuit;
when the power switch tube needs to be switched on, the drive control circuit controls the front-stage switch to be switched off so that the charging module can be charged by using the current output by the current sequence module;
when the power switch tube needs to be turned off, the drive control circuit controls the front-stage switch to be turned on so as to release the charges of the charging module and turn off the source follower switch.
Preferably, the current sequence module comprises a plurality of parallel current sources, and the switching tube sequence module comprises a plurality of parallel MOS tubes.
In another aspect of the present invention, a power switch driving method is further configured, which is applied to the power switch driving circuit described above, and the method includes:
when the power switch tube needs to be switched on, the drive control circuit controls the switch tubes of the switch tube sequence module to be completely switched off, and controls the current sequence module to generate variable charging current, so that the grid voltage of the power switch tube quickly rises to be close to the turn-on threshold value of the power switch tube, and then slowly rises and is kept at the turn-on threshold value;
when the power switch tube needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero so that the source follower switch is turned off, controls the switch tube sequence module to be turned on and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is rapidly reduced to be close to the turn-on threshold value of the power switch tube, slowly reduced to be zero after being slowly reduced to be close to the turn-on threshold value.
Preferably, the controlling the current sequence module to generate a variable charging current comprises:
the first stage is as follows: controlling the current sequence module to generate a first current so as to enable the grid voltage of the power switch tube to rise rapidly until the grid voltage of the power switch tube is detected to rise to approach the opening threshold value, and entering a second stage;
and a second stage: controlling the current sequence module to generate a second current and start timing, wherein the second current is smaller than the first current so that the grid voltage of the power switch tube slowly rises at the stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a first preset time;
and a third stage: controlling the current sequence module to generate a third current and starting timing, wherein the third current is larger than the second current so that the gate voltage of the source follower switch rapidly rises to a limit voltage Vclamp of the charging module, the gate voltage of the power switch tube rises to Vclamp-Vgs along with the rise, vgs represents the voltage difference between the gate and the source when the source follower switch is turned on, and the fourth stage is started when the timing time reaches a second preset time;
a fourth stage: controlling the current sequence module to generate a fourth current that is less than the third current to maintain a gate voltage of the source follower switch at the limit voltage Vclamp.
Preferably, the controlling the switching tube sequence module to conduct and generate the variable equivalent resistance includes:
the first stage is as follows: controlling the equivalent resistance of the switching tube sequence module to be a first equivalent resistance so as to enable the grid voltage of the power switching tube to be rapidly reduced until the grid voltage of the power switching tube is detected to be reduced to be close to the opening threshold value, and entering a second stage;
and a second stage: controlling the equivalent resistance of the switching tube sequence module to be a second equivalent resistance and starting timing, wherein the second equivalent resistance is larger than the first equivalent resistance so that the grid voltage of the power switching tube slowly drops at the stage and is kept at the opening threshold value, and entering a third stage when the timing time reaches a third preset time;
and a third stage: and controlling the equivalent resistance of the switching tube sequence module to be a third equivalent resistance, wherein the third equivalent resistance is smaller than the second equivalent resistance so as to rapidly reduce the grid voltage of the power switching tube to zero.
Preferably, the method further comprises: when the power switch tube needs to be switched on, the drive control circuit controls the front-stage switch to be switched off so that the charging module can be charged by using the current output by the current sequence module; when the power switch tube needs to be turned off, the drive control circuit controls the front-stage switch to be turned on so as to release the charges of the charging module and turn off the source follower switch.
The power switching tube driving circuit and the method have the following beneficial effects: when a power switch tube is conducted, the current sequence module is matched with the charging module, the charging module charges by using current output by the current sequence module to generate voltage to be supplied to a grid electrode of a source electrode follower switch, and the current sequence module is controlled to generate variable charging current, so that the grid electrode voltage of the power switch tube is slowly increased when the grid electrode voltage is quickly increased to be close to a starting threshold value of the power switch tube and is kept at the starting threshold value; when the power switch tube needs to be turned off, the switch tube sequence module is conducted and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is quickly reduced to be close to the turn-on threshold value of the power switch tube, slowly reduced to the turn-on threshold value and then quickly reduced to zero.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only examples of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:
fig. 1 is a circuit diagram of a conventional power switching tube driving circuit;
FIG. 2 is a waveform diagram illustrating operation of a conventional power switch tube driving circuit;
fig. 3 is a circuit diagram of a power switching tube driving circuit of the present invention;
fig. 4 is a waveform diagram of the power switch tube driving circuit of the invention in operation.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Exemplary embodiments of the invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the embodiments and specific features in the embodiments of the present invention are described in detail in the present application, but not limited to the present application, and the features in the embodiments and specific features in the embodiments of the present invention may be combined with each other without conflict.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Example one
Referring to fig. 3, the present embodiment discloses a power switch tube driving circuit, which is used for driving a power switch tube M0, where the power switch tube M0 may be integrated with a chip or not, a source of the power switch tube M0 may be connected to some common PCB components such as a transformer or an inductor, and a source of the power switch tube M0 is grounded through a sampling resistor Rs.
The power switch tube M0 driving circuit of the embodiment includes: the device comprises a grid voltage detection circuit, a source electrode follower switch M1, a pre-stage switch S0, a current sequence module, a charging module, a switching tube sequence module and a driving control circuit.
And the grid voltage detection circuit is connected with the grid of the power switch tube M0 and is used for detecting the grid voltage of the power switch tube M0 in real time.
The drain electrode of the source electrode following switch M1 is connected with a power supply, and the source electrode of the source electrode following switch M1 is connected with the grid electrode of the power switch tube M0, wherein the source electrode following switch M1 adopts an NMOS tube in the embodiment.
And the pre-switch S0 is connected between the grid of the source follower switch M1 and the ground, and the pre-switch S0 can adopt but is not limited to an electronic switch such as a MOS (metal oxide semiconductor) tube, a triode and the like.
The current sequence module may adopt a plurality of current sources connected in parallel, for example, m current sources, where K0[1 m ] in fig. 3 represents a control signal of the m current sources, and the number of current sources put into use is selected, that is, the charging current output by the current sequence module may be changed.
The charging module is connected between the grid of the power switch tube M0 and the ground, the current sequence module is connected with the charging module, and the charging module is used for charging by using the current output by the current sequence module to generate voltage to be supplied to the grid of the source electrode follower switch M1. Specifically, in this embodiment, the charging module includes a clamping voltage regulator diode D0 and a charging capacitor C0, the charging capacitor C0 is connected between the gate of the source follower switch M1 and the ground, and the cathode of the clamping voltage regulator diode D0 is connected to the gate of the source follower switch M1 and the anode is grounded. It is understood that the zener diode D0 may be a plurality of zener diodes connected in series to achieve a higher clamping voltage. In addition, a voltage stabilizing diode can be connected between the grid electrode and the source stage of the source follower switch M1 to protect the source follower switch M1, and the charging capacitor C0 is equivalent to the capacitance from the grid electrode of the source follower switch M1 to the ground.
And the switching tube sequence module comprises a plurality of switching tubes connected in parallel, and the drain electrodes of the switching tubes are connected with the grid electrode and the source electrode of the power switching tube M0 and grounded. For example, n switching tubes M2[1 n ], where K2[ 1.
Specifically, in this embodiment, the switching tube sequence module includes a plurality of NMOS tubes connected in parallel, which have both switching characteristics and equivalent resistance when turned on. It is understood that the NMOS transistor may be replaced by another switching transistor.
And the driving control circuit is respectively connected with the grid voltage detection circuit, the current sequence module, the control end of the pre-stage switch S0 and the grid of the switching tube.
When the power switch tube M0 needs to be turned on, the drive control circuit controls all the switch tubes of the switch tube sequence module to be turned off, controls the pre-stage switch S0 to be turned off so that the charging module charges by using the current output by the current sequence module, and controls the current sequence module to generate a variable charging current so that the gate voltage of the power switch tube M0 rapidly rises to approach the turn-on threshold of the power switch tube M0 and then slowly rises and is kept at the turn-on threshold.
When the power switch tube M0 needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero, and simultaneously controls the pre-stage switch S0 to be switched on so as to release the charge of the charging module and turn off the source follower switch M1, and controls the switch tube sequence module to be switched on and generate a variable equivalent resistance, so that the gate voltage of the power switch tube M0 is rapidly reduced to be close to the turn-on threshold of the power switch tube M0, and then is slowly reduced to be zero after being rapidly reduced to be close to the turn-on threshold.
The on and off processes of the power switch M0 of the present invention will be described in detail with reference to fig. 4.
1) The conduction process of M0 is as follows:
first stage (t 0 period): the driving control circuit controls all the switching tubes M2[ 1N ] and the front-stage switch S0 of the switching tube sequence module to be turned off, the current sequence module Is controlled to generate a charging current Is (N), the charging current Is (N) at the stage Is the first current Is0, the generated charging current Is (N) charges the charging capacitor C0, namely, the grid voltage Vc of the source electrode following switch M1 starts to rise rapidly, and meanwhile, the grid voltage Vgate of the power switching tube M0 follows the grid voltage Vc of the source electrode following switch M1. The second phase is entered until the gate voltage detection circuit detects that the gate voltage Vgate of the power switch transistor M0 rises to approach the turn-on threshold Vt0, where the approach means that Vgate is smaller than Vt0 by a preset voltage difference, and the preset voltage difference is a very small voltage, for example, a voltage within 10% of Vt 0.
Second stage (t 1 period): and controlling the size of the charging current Is (N) generated by the current sequence module to be a second current Is1 and starting timing, wherein the second current Is1 Is smaller than the first current Is0, entering a third stage when the timing time reaches a first preset time t1, and the t1 Is set by the interior of the driving control circuit.
In the time t1, the gate voltage Vc of the source follower switch M1 changes slowly due to the fact that Is1 Is small, the miller effect exists in the power switch tube M0 (when the Vds voltage approaches the Vgs voltage, parasitic capacitance Cgd of the gate and the drain changes along with the voltage difference Vgd between the gate and the drain, and when the Vds voltage approaches the Vgs voltage, cgd changes to the maximum), the gate voltage Vgate of the power switch tube M0 rises slowly and Is kept near the turn-on threshold Vt0, the power switch tube M0 starts to be turned on when the gate voltage Vgate reaches Vt0, the peripheral transformer or inductor current starts to rise, the current from the drain of the power switch tube M0 to the source passes through the sampling resistor Rs, the sampling voltage Vs Is obtained, and at this time, the voltage Vs Is low, and the power switch tube M0 has low loss.
Third stage (t 2 period): controlling the magnitude of the charging current Is (N) generated by the current sequence module to be a third current Is2 and starting timing, wherein the third current Is2 Is greater than the second current Is1, so that the gate voltage Vc of the source follower switch M1 rapidly rises to the limit voltage Vclamp of the clamping diode, and simultaneously the gate voltage Vgate of the power switch tube M0 rises to Vclamp-Vgs, which represents the voltage difference between the gate and the source when the source follower switch M1 Is turned on, and entering a fourth stage when the timing time reaches a second preset time period t 2;
fourth stage (t 3 period): and controlling the magnitude of the charging current Is (N) generated by the current sequence module to be a fourth current Is3, wherein the fourth current Is3 Is smaller than the third current Is2, so that the gate voltage Vc of the source follower switch M1 Is kept at the limit voltage Vclamp. In this way, the gate voltage Vgate of the power switch transistor M0 is kept unchanged by using a small current at this stage, so as to reduce the driving power consumption.
2) The turn-off process of M0 is as follows:
first stage (t 4 period): the driving control circuit controls the charging current Is (N) generated by the current sequence module to be 0, the switching tube sequence module and the pre-stage switch S0 are turned on, and the equivalent resistor R2 (on) _ M2_ N of the switching tube sequence module Is the first equivalent resistor R2 (on) _1, so that the gate voltage Vc of the source follower switch M1 rapidly drops to 0V, and the gate voltage Vgate of the power switching tube M0 rapidly drops until the gate voltage detection circuit detects that the gate voltage Vgate of the power switching tube M0 drops to approach the turn-on threshold Vt0, and enters a second stage, where the approach means that Vgate Is larger than Vt0 by a preset voltage difference, and the preset voltage difference Is a very small voltage, for example, a voltage within 10% of Vt 0.
Second stage (t 5 period): and controlling an equivalent resistor R2 (on) _ M2_ N of the switching tube sequence module to be a second equivalent resistor R (on) _2, starting timing, and entering a third stage when the timing time reaches a third preset time period t 5. At this stage, since the second equivalent resistor R (on) _2 is greater than the first equivalent resistor R (on) _1, the gate voltage Vgate of the power switch M0 slowly decreases, and since the miller effect exists in the power switch M0, the Vgate is kept near the turn-on threshold Vt0, and at this time, the drain voltage of the power switch M0 is low, and the power switch M0 has low loss.
Third stage (t 6 period): and controlling an equivalent resistor R2 (on) _ M2_ N of the switching tube sequence module to be a third equivalent resistor R (on) _3, wherein the third equivalent resistor R (on) _3 is smaller than the second equivalent resistor R (on) _2 so as to quickly reduce the grid voltage of the power switching tube M0 to zero.
In summary, the present embodiment can achieve better EMI characteristics, which are reflected in that the Vs waveform has less interference and the rising and falling speed of the drain voltage of the power switch transistor is smoother, and the switching delay is reduced, and the efficiency is optimized, so that the present embodiment has wide applicability.
Example two
The power switching tube driving method of the present embodiment is applied to the power switching tube driving circuit according to any one of claims 1 to 6, and the method includes:
s1) when the power switch tube M0 needs to be conducted, the drive control circuit controls all switch tubes of the switch tube sequence module to be turned off, controls the pre-stage switch S0 to be turned off, and controls the current sequence module to generate variable charging current, so that the grid voltage of the power switch tube M0 rapidly rises to be close to a starting threshold value of the power switch tube M0, then slowly rises and is kept at the starting threshold value;
wherein the controlling the current sequence module to generate a variable charging current comprises:
the first stage is as follows: controlling the current sequence module to generate a first current so as to enable the grid voltage of the power switch tube M0 to rise rapidly until the grid voltage of the power switch tube M0 is detected to rise to approach the opening threshold value, and entering a second stage;
and a second stage: controlling the current sequence module to generate a second current and starting timing, wherein the second current is smaller than the first current so that the grid voltage of the power switch tube M0 slowly rises at the stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a first preset time t 1;
and a third stage: controlling the current sequence module to generate a third current and starting timing, wherein the third current is greater than the second current so that the gate voltage of the source follower switch M1 rapidly rises to the limit voltage Vclamp of the charging module, meanwhile, the gate voltage of the power switch tube M0 rises to Vclamp-Vgs along with the rise of the gate voltage, vgs represents the voltage difference between the gate and the source when the source follower switch M1 is turned on, and the fourth stage is started when the timing time reaches a second preset time period t 2;
a fourth stage: controlling the current sequence module to generate a fourth current that is less than the third current to maintain the gate voltage of the source follower switch M1 at the limit voltage Vclamp.
And S2) when the power switch tube M0 needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero, controls the pre-stage switch S0 to be switched on to release the charge of the charging module so as to turn off the source electrode follower switch M1, controls the switch tube sequence module to be switched on and generates a variable equivalent resistance, so that the grid voltage of the power switch tube M0 is quickly reduced to be close to the turn-on threshold value of the power switch tube M0, then slowly reduced to the turn-on threshold value and then quickly reduced to be zero.
Wherein, the said control the said switch tube serial module switches on and produces the variable equivalent resistance, including:
the first stage is as follows: controlling the equivalent resistance of the switching tube sequence module to be a first equivalent resistance so as to enable the grid voltage of the power switching tube M0 to be rapidly reduced until the grid voltage of the power switching tube M0 is detected to be reduced to be close to the starting threshold value, and entering a second stage;
and a second stage: controlling the equivalent resistance of the switching tube sequence module to be a second equivalent resistance and starting timing, wherein the second equivalent resistance is larger than the first equivalent resistance so that the grid voltage of the power switching tube M0 is slowly reduced in this stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a third preset time t 5;
and a third stage: and controlling the equivalent resistance of the switching tube sequence module to be a third equivalent resistance, wherein the third equivalent resistance is smaller than the second equivalent resistance so as to rapidly reduce the grid voltage of the power switching tube M0 to zero.
Further details may be found in the embodiments and will not be described herein.
The terms "equal," "same," "simultaneously," "maintaining," or other similar terms, as used herein, are not limited to absolute equality or equality in mathematical terms, but may be close in an engineering sense or within an acceptable error range when practicing the claims of this patent. The term "coupled" or "connecting" is intended to encompass not only the direct connection of two entities, but also the indirect connection through other entities with beneficial and improved effects.
The terms "first", "second", and the like, including ordinal numbers, used in the present specification may be used to describe various components, but the components are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from other constituent elements. For example, a first component may be named a second component, and similarly, a second component may also be named a first component, without departing from the scope of the present invention.
While the present invention has been described with reference to the particular illustrative embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications, equivalent arrangements, and equivalents thereof, which may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A power switching tube driver circuit, the driver circuit comprising:
the grid voltage detection circuit is connected with the grid of the power switch tube and is used for detecting the grid voltage of the power switch tube in real time;
the drain electrode of the source electrode following switch is connected with a power supply, and the source electrode of the source electrode following switch is connected with the grid electrode of the power switch tube;
the charging module is connected between the grid of the source electrode following switch and the ground and used for charging by using the current output by the current sequence module to generate voltage to be supplied to the grid of the source electrode following switch;
the switching tube sequence module comprises a plurality of switching tubes connected in parallel, the drain electrodes of the switching tubes are connected with the grid electrodes of the power switching tubes, and the source electrodes of the switching tubes are grounded;
the driving control circuit is respectively connected with the grid voltage detection circuit, the current sequence module, the grid of the source electrode follower switch and the grid of the switching tube, and controls the switching tubes of the switching tube sequence module to be completely turned off when the power switching tube needs to be turned on, and controls the current sequence module to generate variable charging current so that the grid voltage of the power switching tube slowly rises when rapidly rising to approach the turn-on threshold value of the power switching tube and then keeps at the turn-on threshold value; when the power switch tube needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero so that the source electrode follows the switch to be turned off, controls the switch tube sequence module to be turned on and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is quickly reduced to the turn-on threshold value when the grid voltage is quickly reduced to be close to the turn-on threshold value of the power switch tube, and then is quickly reduced to be zero.
2. The power switching tube driving circuit as claimed in claim 1, wherein said controlling said current sequence module to generate a variable charging current comprises:
the first stage is as follows: controlling the current sequence module to generate a first current so as to enable the grid voltage of the power switch tube to rise rapidly until the grid voltage of the power switch tube is detected to rise to approach the opening threshold value, and entering a second stage;
and a second stage: controlling the current sequence module to generate a second current and start timing, wherein the second current is smaller than the first current so that the grid voltage of the power switch tube slowly rises at the stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a first preset time;
and a third stage: controlling the current sequence module to generate a third current and starting timing, wherein the third current is larger than the second current so that the gate voltage of the source follower switch can quickly rise to a limit voltage Vclamp of the charging module, meanwhile, the gate voltage of the power switch tube rises to Vclamp-Vgs along with the rise of the gate voltage, vgs represents the voltage difference between the gate and the source when the source follower switch is turned on, and when the timing time reaches a second preset time, entering a fourth stage;
a fourth stage: controlling the current sequence module to generate a fourth current that is less than the third current to maintain a gate voltage of the source follower switch at the limit voltage Vclamp.
3. The power switching tube driving circuit according to claim 1, wherein the controlling the switching tube sequence module to conduct and generate the variable equivalent resistance comprises:
the first stage is as follows: controlling the equivalent resistance of the switching tube sequence module to be a first equivalent resistance so as to enable the grid voltage of the power switching tube to be rapidly reduced until the grid voltage of the power switching tube is detected to be reduced to be close to the opening threshold value, and entering a second stage;
and a second stage: controlling the equivalent resistance of the switching tube sequence module to be a second equivalent resistance and starting timing, wherein the second equivalent resistance is larger than the first equivalent resistance so that the grid voltage of the power switching tube slowly drops at the stage and is kept at the opening threshold value, and entering a third stage when the timing time reaches a third preset time;
and a third stage: and controlling the equivalent resistance of the switching tube sequence module to be a third equivalent resistance, wherein the third equivalent resistance is smaller than the second equivalent resistance so as to rapidly reduce the grid voltage of the power switching tube to zero.
4. The power switching tube driving circuit according to claim 1, wherein the charging module comprises a clamping voltage stabilizing diode and a charging capacitor, the charging capacitor is connected between the gate of the source follower switch and ground, the negative electrode of the clamping voltage stabilizing diode is connected with the gate of the source follower switch, and the positive electrode of the clamping voltage stabilizing diode is connected with the ground.
5. The power switching tube driving circuit according to claim 4, wherein the driving circuit further comprises a pre-switch, the pre-switch is connected between the gate of the source follower switch and ground, and the control end of the pre-switch is connected to the driving control circuit;
when the power switch tube needs to be switched on, the drive control circuit controls the front-stage switch to be switched off so that the charging module can be charged by using the current output by the current sequence module;
when the power switch tube needs to be turned off, the driving control circuit controls the pre-stage switch to be turned on so as to release the charges of the charging module, and therefore the source electrode follower switch is turned off.
6. The power switch tube driving circuit according to claim 1, wherein the current sequence module comprises a plurality of parallel current sources, and the switch tube sequence module comprises a plurality of parallel MOS tubes.
7. A power switch tube driving method is applied to the power switch tube driving circuit of any one of claims 1-6, and is characterized by comprising the following steps:
when the power switch tube needs to be switched on, the drive control circuit controls all the switch tubes of the switch tube sequence module to be switched off, and controls the current sequence module to generate variable charging current, so that the grid voltage of the power switch tube quickly rises to be close to the turn-on threshold value of the power switch tube, then slowly rises and is kept at the turn-on threshold value;
when the power switch tube needs to be turned off, the drive control circuit controls the current output by the current sequence module to be zero so that the source follower switch is turned off, controls the switch tube sequence module to be turned on and generates a variable equivalent resistance, so that the grid voltage of the power switch tube is rapidly reduced to be close to the turn-on threshold value of the power switch tube, slowly reduced to be zero after being slowly reduced to be close to the turn-on threshold value.
8. The power switching tube driving method according to claim 7, wherein the controlling the current sequence module to generate the variable charging current comprises:
the first stage is as follows: controlling the current sequence module to generate a first current so as to enable the grid voltage of the power switch tube to rise rapidly until the grid voltage of the power switch tube is detected to rise to approach the opening threshold value, and entering a second stage;
and a second stage: controlling the current sequence module to generate a second current and start timing, wherein the second current is smaller than the first current so that the grid voltage of the power switch tube slowly rises at the stage and is kept at the starting threshold value, and entering a third stage when the timing time reaches a first preset time;
and a third stage: controlling the current sequence module to generate a third current and starting timing, wherein the third current is larger than the second current so that the gate voltage of the source follower switch rapidly rises to a limit voltage Vclamp of the charging module, the gate voltage of the power switch tube rises to Vclamp-Vgs along with the rise, vgs represents the voltage difference between the gate and the source when the source follower switch is turned on, and the fourth stage is started when the timing time reaches a second preset time;
a fourth stage: controlling the current sequence module to generate a fourth current that is less than the third current to maintain a gate voltage of the source follower switch at the limit voltage Vclamp.
9. The method as claimed in claim 7, wherein the step of controlling the switching transistor sequence module to conduct and generate the variable equivalent resistance comprises:
the first stage is as follows: controlling the equivalent resistance of the switching tube sequence module to be a first equivalent resistance so as to enable the grid voltage of the power switching tube to be rapidly reduced until the grid voltage of the power switching tube is detected to be reduced to be close to the opening threshold value, and entering a second stage;
and a second stage: controlling the equivalent resistance of the switching tube sequence module to be a second equivalent resistance and starting timing, wherein the second equivalent resistance is larger than the first equivalent resistance so that the grid voltage of the power switching tube is slowly reduced and kept at the starting threshold value at the stage, and entering a third stage when the timing time reaches a third preset time;
and a third stage: and controlling the equivalent resistance of the switching tube sequence module to be a third equivalent resistance, wherein the third equivalent resistance is smaller than the second equivalent resistance so as to rapidly reduce the grid voltage of the power switching tube to zero.
10. The power switch tube driving method according to claim 7, wherein the charging module includes a clamping voltage regulator diode and a charging capacitor, the charging capacitor is connected between the gate of the source follower switch and ground, the cathode of the clamping voltage regulator diode is connected with the gate of the source follower switch, the anode of the clamping voltage regulator diode is connected with ground, the driving circuit further includes a pre-stage switch, the pre-stage switch is connected between the gate of the source follower switch and ground, and the control terminal of the pre-stage switch is connected with the driving control circuit;
the method further comprises the following steps: when the power switch tube needs to be switched on, the drive control circuit controls the front-stage switch to be switched off so that the charging module can be charged by using the current output by the current sequence module; when the power switch tube needs to be turned off, the driving control circuit controls the pre-stage switch to be turned on so as to release the charges of the charging module, and therefore the source electrode follower switch is turned off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110923548.3A CN115706505A (en) | 2021-08-12 | 2021-08-12 | Power switching tube driving circuit and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110923548.3A CN115706505A (en) | 2021-08-12 | 2021-08-12 | Power switching tube driving circuit and method |
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| Publication Number | Publication Date |
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| CN115706505A true CN115706505A (en) | 2023-02-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110923548.3A Pending CN115706505A (en) | 2021-08-12 | 2021-08-12 | Power switching tube driving circuit and method |
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| CN (1) | CN115706505A (en) |
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