A transistor drive control circuit, method and drive system

Abstract

The present invention discloses a transistor drive control circuit, comprising a drive current control unit coupled to a transistor; the drive current control unit is configured to output a drive current signal to drive the transistor, and to determine the operating state of the transistor based on a signal fed back by the transistor, and to forcibly shut down or maintain the drive of the transistor based on the operating state; the drive current control unit is further configured to, upon detecting that the transistor is in an amplification region in the current cycle, control the amplitude of the drive current signal obtained by the transistor in the next cycle to increase by an amplitude variation. The present invention also discloses a transistor drive control method and a transistor drive system. The present invention can detect the operating state of the transistor in real time, and upon detecting that the transistor has entered the amplification region, implement a forced shutdown action in advance, and control the amplitude of the drive current signal of the transistor in the next cycle to increase.

Description

Technical Field

[0001] The present invention relates to the field of electronic information, and in particular to a transistor drive control circuit, method and drive system. Background Art

[0002] Power transistors (BJT) are widely used in small and medium power chargers and adapter power supplies due to their price advantage. Figure 1 This is a basic application circuit for power transistors. Power transistors are current-driven semiconductor devices. After the drive current of a power transistor decreases to zero, the power transistor does not turn off immediately. This is known as the "current tailing effect" or "memory effect." To control the turn-off timing of the power transistor, not only must the drive current be reduced to zero, but the base and emitter of the power transistor must also be short-circuited. Reducing the drive current to zero is called "pre-shutdown," while shorting the base and emitter is called "forced shutdown."

[0003] The essence of the "forced shutdown" of the power transistor is to discharge the residual charge in the transistor base, which will waste circuit energy. Figure 2 This is a working timing diagram of a power transistor, as shown in the attached figure. Figure 2 As shown in the figure, usually the "forced shutdown" action of the power transistor lags behind the "pre-shutdown" for a certain period of time to reduce the waste of circuit energy. Figure 2 As shown, the time of the forced shutdown action 310 at the negative current lags behind the time of the pre-shutdown action 320 , and thus the time of the forced shutdown action 330 lags behind the time of the pre-shutdown action 320 .

[0004] Taking the flyback topology application as an example, the current transistor drive control technology determines the time of "pre-shutdown" and "forced shutdown" by detecting the transistor current IC(t) flowing through the power transistor. Figure 3 This is the normal working timing diagram of the power transistor flyback topology application, as shown in the attached figure. Figure 3 As shown, when the transistor current IC(t) flowing through the power transistor reaches the first transistor current IC1, the power transistor is "pre-shutdown", that is, the drive current IB(t) is reduced from the first drive current IB1 to 0; when the transistor current IC(t) flowing through the power transistor reaches the second transistor current IC2, the power transistor is "forced shutoff", that is, the base and emitter are short-circuited, and a negative current forced shutoff action 310 is performed to reduce the drive current IB(t) to the negative second drive current IB2. The amplitude of the drive current IB(t) is generally fixed, and the shape of the drive current IB(t) can be additional Figure 5 The triangle wave shown in the figure is Figure 6 The rectangular wave shown or the attached Figure 7 The design of the threshold values of the first transistor current IC1 and the second transistor current IC2 in the composite wave shown is also based on experience, so the applicable range is narrow. When the temperature changes over a large range or the power changes, it may cause the driving current IB(t) to not match the actual power. Figure 4 This is the working timing diagram of the power transistor flyback topology application entering the amplification area. Figure 4 As shown, the most serious situation is insufficient driving current IB(t). A typical phenomenon is that the power transistor enters the amplification region 340 before forced shutdown, that is, the time when the power transistor enters the amplification region 340 is earlier than the time of the negative current forced shutdown action 310, which will cause the power transistor loss to increase sharply or even be damaged. Summary of the Invention

[0005] The present invention addresses the deficiencies in the prior art and provides a transistor drive control circuit, method and drive system.

[0006] In order to solve the above technical problems, the present invention is solved by the following technical solutions:

[0007] The present invention provides a transistor drive control circuit, comprising a drive current control unit coupled to a transistor; the drive current control unit is used to output a drive current signal to drive the transistor, and to determine the working state of the transistor based on a signal fed back by the transistor, and to perform a forced shutdown action or maintain a drive action on the transistor based on the working state; the drive current control unit is further used to control the amplitude of the drive current signal to increase by an amplitude variation in the next cycle after detecting that the transistor is in an amplification region in the current cycle.

[0008] Optionally, the driving current control unit includes:

[0009] A driving module, configured to generate the driving current signal for driving the transistor;

[0010] A sampling module, used to obtain a sampling signal used to represent the current flowing through the transistor;

[0011] A shutdown module, used for generating a forced shutdown signal for short-circuiting the base and emitter of the transistor;

[0012] A feedback module, used to obtain a feedback signal for determining the working state of the transistor;

[0013] The sampling module and the feedback module are both coupled to the driving module; the driving module outputs the driving current signal and adjusts the amplitude of the driving current signal according to the sampling signal and the feedback signal; the sampling module and the feedback module are both coupled to the shutdown module; the shutdown module outputs the forced shutdown signal according to the sampling signal and the feedback signal.

[0014] Optionally, the device further includes an isolated flyback converter circuit coupled to the drive current control unit, the isolated flyback converter circuit being configured to obtain the drive current signal and the forced shutdown signal from the drive current control unit to control the transistor, and providing the sampling signal to the drive current control unit. The isolated flyback converter circuit includes a feedback circuit coupled to the drive current control unit for providing the feedback signal to the drive current control unit.

[0015] Optionally, the isolated flyback conversion circuit also includes a sampling circuit; the sampling circuit is used to generate the sampling signal representing the current flowing through the transistor; the driving current control unit determines the working state of the transistor based on the sampling signal and the feedback signal.

[0016] Optionally, when the driving current control unit detects that the sampling signal increases to a first sampling threshold, it controls the driving current signal to decrease to a set threshold.

[0017] Optionally, when the driving current control unit detects that the sampling signal increases to a second sampling threshold, it controls the base and emitter of the transistor to be short-circuited, and the transistor is turned off; the second sampling threshold is greater than the first sampling threshold.

[0018] Optionally, the driving current control unit determines that the transistor enters the amplification region when detecting that the sampling signal has not increased to the second sampling threshold but the feedback signal has increased and exceeded a third voltage threshold.

[0019] Optionally, a first switch tube is electrically connected between the base of the transistor and the emitter of the transistor; when the first switch tube is in an on state, the base of the transistor and the emitter of the transistor are short-circuited.

[0020] Optionally, the sampling circuit includes a sampling resistor, the emitter of the transistor is electrically connected to one end of the sampling resistor, and the other end of the sampling resistor is grounded; the feedback circuit includes a first resistor and a second resistor connected in series, and the voltage obtained by series voltage division across the second resistor is the feedback signal.

[0021] Optionally, the driving current control unit includes:

[0022] a driving end coupled to the driving module, the driving end being electrically connected to the base of the transistor and outputting the driving current signal to the base of the transistor;

[0023] a sampling terminal coupled to the sampling module, the sampling terminal being electrically connected between the emitter of the transistor and the sampling resistor, and acquiring the voltage across the sampling resistor as the sampling signal;

[0024] a first switch control terminal coupled to the shutdown module, the first switch control terminal being coupled to the first switch and controlling the first switch by outputting the forced shutdown signal to the first switch;

[0025] A feedback terminal coupled to the feedback module is electrically connected between the first resistor and the second resistor, and obtains a voltage across the second resistor as the feedback signal.

[0026] The present invention further provides a transistor drive system, comprising any one of the above-mentioned transistor drive control circuits.

[0027] The present invention also provides a transistor drive control method, comprising the following steps:

[0028] In the current cycle, the transistor is driven with the first driving current, thereby controlling the transistor to be turned on, and the current flowing through the transistor begins to increase;

[0029] When the current flowing through the transistor increases to a first sampling threshold, controlling the driving current signal to decrease to a set threshold; and

[0030] When the current flowing through the transistor has not increased to the second sampling threshold, but the feedback signal has increased and exceeded the third voltage threshold, the base and emitter of the transistor are controlled to be short-circuited, and the transistor is turned off; the second sampling threshold is greater than the first sampling threshold;

[0031] In the next cycle, the transistor is driven with a second driving current, where the second driving current is greater than the first driving current.

[0032] Optionally, when the current flowing through the transistor increases to a second sampling threshold, the base and emitter of the transistor are controlled to be short-circuited, thereby controlling the transistor to be turned off.

[0033] The present invention can detect the working state of the transistor in real time. Once it is detected that the transistor enters the amplification area, the "forced shutdown" action will be implemented in advance, that is, the first switch tube is controlled to be closed, so that the base and emitter of the transistor are short-circuited and grounded, thereby immediately shutting down the transistor and controlling the amplitude of the driving current signal of the transistor in the next cycle to increase.

[0034] The present invention ensures sufficient drive current signals for the next cycle, preventing the transistor from entering the amplification region before forced shutdown due to insufficient drive current, thereby reducing the risk of a sharp increase in transistor losses, protecting the transistor, and reducing the possibility of transistor damage. This broadens the scope of application, and when the operating temperature or power of the transistor varies widely, a drive current signal that matches the actual power can be provided to the transistor, thereby optimizing the operating efficiency and temperature rise of the transistor.

[0035] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0037] Figure 1 A basic application circuit of a power transistor according to the prior art;

[0038] Figure 2 This is a working timing diagram of a power transistor according to the prior art;

[0039] Figure 3 This is a normal working timing diagram of a power transistor flyback topology application according to the prior art;

[0040] Figure 4 This is a timing diagram of a power transistor flyback topology application entering the amplification region according to the prior art;

[0041] Figure 5 The current is driven by a triangular wave state according to the prior art;

[0042] Figure 6 The current is driven by a rectangular wave state according to the prior art;

[0043] Figure 7 The driving current is a composite wave state according to the prior art;

[0044] Figure 8 This is a circuit diagram of a transistor drive control circuit according to an embodiment of the present invention;

[0045] Figure 9 This is a timing diagram of various signals when a transistor drive control circuit according to an embodiment of the present invention is in normal operation;

[0046] Figure 10This is a timing diagram of various signals when a transistor drive control circuit enters an amplification region according to an embodiment of the present invention;

[0047] Figure 11 The figure is a schematic diagram of a drive current control unit module in a transistor drive control circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the present patent application specification and claims do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation of quantity, but rather denote the presence of at least one.

[0050] The present invention discloses an embodiment of a transistor drive control circuit, which has the advantages of high reliability and adaptability. It can detect the operating state of a transistor Q in real time. Once it is detected that the transistor Q enters the amplification region, it will implement a "forced shutdown" action in advance and control the amplitude of the driving current signal Ibase of the transistor Q to increase. The "forced shutdown" of this embodiment is achieved by immediately short-circuiting the base of the transistor Q and the emitter of the transistor Q; and by controlling the amplitude of the driving current signal Ibase of the transistor Q to increase by a certain amplitude change ΔI in subsequent switching cycles, thereby controlling the amplitude of the driving current signal Ibase of the transistor Q to increase.

[0051] The transistor Q used in this embodiment is a power transistor. The operating state of the transistor Q can be determined by directly detecting the sixth voltage Vce between the collector and emitter of the transistor Q. It should be understood that the sixth voltage Vce of the transistor Q in the saturated conduction state is very small. When the sixth voltage Vce exceeds a certain voltage threshold, it can be determined that the transistor Q has entered the amplification region. This embodiment uses the feedback signal VFB of the feedback circuit 130 to represent the change in the sixth voltage Vce. Therefore, this embodiment determines the operating state of the transistor Q by detecting the change in the feedback signal VFB.

[0052] It should be understood that the driving current signal Ibase of transistor Q used in this embodiment is a rectangular wave. In other embodiments, the selection is not limited to this embodiment, and other driving current signal waveforms Ibase may be selected based on actual needs. The driving current signal Ibase of this embodiment has an initial amplitude, namely, the initial driving amplitude; the driving current signal Ibase of transistor Q is controlled to increase by a certain amplitude change ΔI. Assuming that the previous driving current signal Ibase is the first driving current I1, the amplitude change ΔI is increased by a certain amplitude change ΔI based on the amplitude of the first driving current I1, that is, the amplitude of the first driving current I1 is increased to (I1 + ΔI).

[0053] This embodiment discloses a transistor drive control circuit, including a drive current control unit 200 coupled to a transistor Q. The drive current control unit 200 is configured to output a drive current signal Ibase to drive the transistor Q, determine the operating state of the transistor Q based on a signal fed back from the transistor Q, and forcefully shut down or maintain drive of the transistor Q based on the operating state. The drive current control unit 200 is further configured to, upon detecting that the transistor Q is in an amplification region during the current cycle, increase the amplitude of the drive current signal Ibase obtained by the transistor Q during the next cycle by an amplitude variation ΔI.

[0054] Among them, as attached Figure 11 As shown, the driving current control unit 200 includes:

[0055] The driving module 201 is used to generate a driving current signal Ibase for driving the transistor Q;

[0056] The sampling module 202 is used to obtain a sampling signal Vcs used to represent the current flowing through the transistor Q;

[0057] The shutdown module 203 is used to generate a forced shutdown signal Vgsl for short-circuiting the base and emitter of the transistor Q;

[0058] A feedback module 204 is used to obtain a feedback signal VFB for determining the working state of the transistor Q;

[0059] In one embodiment of a transistor drive control circuit, sampling module 202 and feedback module 204 are both coupled to driver module 201 and transmit their acquired sampling signal Vcs and feedback signal VFB to driver module 201 for evaluation. Driver module 201 outputs a drive current signal Ibase based on the sampling signal Vcs and feedback signal VFB, and adjusts the amplitude of drive current signal Ibase.

[0060] In one embodiment of the transistor drive control circuit, the sampling module 202 and the feedback module 204 are both coupled to the shutdown module 203 and transmit the sampled signal Vcs and the feedback signal VFB obtained by each module to the shutdown module 203 for determination. The shutdown module 203 outputs a forced shutdown signal Vgsl based on the sampled signal Vcs and the feedback signal VFB.

[0061] In an embodiment of a transistor drive control circuit, as shown in the attached Figure 8 As shown, the transistor drive control circuit further includes an isolated flyback converter circuit 100. A drive current control unit 200 is coupled to the isolated flyback converter circuit 100. The isolated flyback converter circuit 100 includes a transistor Q. The drive current control unit 200 turns on the transistor Q by outputting a drive current signal Ibase to the isolated flyback converter circuit 100, and turns off the transistor Q by outputting a forced shutdown signal Vgsl to the isolated flyback converter circuit 100. The drive current control unit 200 is further configured to, upon detecting that the transistor Q is in the amplification region in the current cycle, control the amplitude of the drive current signal Ibase obtained by the transistor Q in the next cycle to increase by an amplitude variation ΔI.

[0062] In an embodiment of a transistor drive control circuit, as shown in the attached Figure 8 As shown, the isolated flyback converter circuit 100 includes a transistor Q, a feedback circuit 130, and a secondary circuit 120. The collector of the transistor Q is coupled to the feedback circuit 130 via a transformer T, and is also coupled to the secondary circuit 120 via the transformer T. The drive current control unit 200 is coupled to the isolated flyback converter circuit 100 and outputs a drive current signal Ibase and a forced shutdown signal Vgsl to the isolated flyback converter circuit 100. Specifically, the drive current control unit 200 is coupled to the feedback circuit 130 and determines the operating state of the transistor Q based on the feedback signal VFB obtained from the feedback circuit 130.

[0063] As attached Figure 8 As shown, in one embodiment, the transformer T includes a primary winding T1 , a secondary winding T2 and an auxiliary winding T3 .

[0064] In an embodiment of a transistor drive control circuit, as shown in the attached Figure 8 As shown, one end of the primary winding T1 (the same-name terminal of the primary winding T1) is coupled to the collector of the transistor Q, the other end of the primary winding T1 (the opposite-name terminal of the primary winding T1) is coupled to the positive electrode of the DC voltage source DC, and the negative electrode of the DC current source is grounded. A first inductor Lm is connected in parallel across both ends of the primary winding T1.

[0065] The isolated flyback converter circuit 100 includes a sampling circuit. The sampling circuit is used to generate a sampling signal Vcs representing the current flowing through the transistor Q. In one embodiment, the sampling signal Vcs is used to:

[0066] The driving current control unit 200 controls the driving current signal Ibase according to the sampling signal Vcs. When the driving current control unit 200 detects that the sampling signal Vcs increases to a first sampling threshold, it controls the driving current signal Ibase to decrease to a set threshold.

[0067] The drive current control unit 200 controls the on / off state of transistor Q based on the sampling signal Vcs. When the drive current control unit 200 detects that the sampling signal Vcs reaches a second sampling threshold, it short-circuits the base and emitter of transistor Q, turning transistor Q off. The second sampling threshold is greater than the first sampling threshold.

[0068] The drive current control unit 200 determines the operating state of the transistor Q based on the sampling signal Vcs and the feedback signal VFB. When the drive current control unit 200 detects that the sampling signal Vcs has not increased to the second sampling threshold, but the feedback signal VFB has increased and exceeded the third voltage threshold, it determines that the transistor Q has entered the amplification region.

[0069] In one embodiment of the transistor drive control circuit, the sampling circuit includes a sampling resistor Rcs. Figure 8 As shown, the first switch tube S1 is electrically connected between the base of the transistor Q and the emitter of the transistor Q. One end of the sampling resistor Rcs is electrically connected to the emitter of the transistor Q, and the other end of the sampling resistor Rcs is grounded. Figure 8 As shown, a first terminal a1 of the first switch tube S1 is coupled to the base of the transistor Q, a second terminal a2 of the first switch tube S1 is coupled to the emitter of the transistor Q, and a third terminal a3 of the first switch tube S1 is coupled to the first switch tube control terminal P2 of the drive current control unit 200 and obtains a forced shutdown signal Vgsl from the first switch tube control terminal P2. The first switch tube S1 determines its own conduction and shutdown according to the forced shutdown signal Vgsl, thereby controlling the base of the transistor Q and the emitter of the transistor Q to be short-circuited and disconnected.

[0070] In one embodiment of the transistor drive control circuit, the secondary circuit 120 includes a secondary winding T2. Figure 8 As shown, the secondary winding T2 is connected in series with the diode D and the first capacitor C0 to form a loop, and the third resistor RL is connected in parallel with the first capacitor C0. The same-pole terminal of the secondary winding T2 is electrically connected to the anode of the diode D, the cathode of the diode D is electrically connected to one end of the first capacitor C0, and the other end of the first capacitor C0 is electrically connected to the opposite-pole terminal of the secondary winding T2. The third resistor RL is connected in parallel across the first capacitor C0.

[0071] In one embodiment of the transistor drive control circuit, the feedback circuit 130 includes an auxiliary winding T3. Figure 8 As shown, an auxiliary winding T3 is connected in series with a first resistor R1 and a second resistor R2. The same-signal end of the auxiliary winding T3 is electrically connected to the first resistor R1, and the opposite-signal end of the auxiliary winding T3 is electrically connected to the second resistor R2. The opposite-signal end of the auxiliary winding T3 and the second resistor R2 are connected to a common connection point connected to ground. In this embodiment, a voltage signal obtained by series voltage division across the second resistor R2 is used as the feedback signal VFB.

[0072] In an embodiment of a transistor drive control circuit, as shown in the attached Figure 8 As shown, the driving current control unit 200 includes a driving terminal P3 coupled to the driving module 201; a first switch tube control terminal P2 coupled to the shutdown module 203; a sampling terminal P1 coupled to the sampling module 202; and a feedback terminal P4 coupled to the feedback module 204.

[0073] The driving terminal P3 is electrically connected to the base of the transistor Q and is used to provide a driving current signal Ibase to the base of the transistor Q.

[0074] The sampling terminal P1 is electrically connected to the emitter of the transistor Q and is electrically connected to the line between the sampling resistor Rcs and the emitter of the transistor Q. The sampling terminal P1 is used to obtain the voltage across the sampling resistor Rcs as a sampling signal Vcs. Because the sampling current flowing through the sampling resistor Rcs is the current flowing through the transistor Q, the sampling signal Vcs can represent the current flowing through the transistor Q.

[0075] The first switch control terminal P2 is coupled to the first switch S1. The forced shutdown signal Vgsl generated by the first switch control terminal P2 is used to directly control the closing of the first switch S1. That is, the first switch control terminal P2 is used to control the closing and opening of the first switch S1. In the closed and conductive state, the first switch short-circuits the base of the transistor Q and the emitter of the transistor Q, thereby implementing forced shutdown of the transistor Q.

[0076] The feedback terminal P4 is electrically connected to the circuit between the first resistor R1 and the second resistor R2. That is, the common connection terminal of the first resistor R1 and the second resistor R2 is electrically connected to the feedback terminal P4. The voltage signal obtained by the auxiliary winding T3 is divided by the first resistor R1 and the second resistor R2 to generate a feedback signal VFB. The feedback signal VFB is fed back to the drive current control unit 200 through the feedback terminal P4. In this embodiment, the voltage signal across the second resistor R2 is the feedback signal VFB.

[0077] In summary, the driving current control unit 200 is configured to receive the feedback signal VFB and the sampling signal Vcs of the isolated flyback converter circuit 100 , and generate the driving current signal Ibase and the forced shutdown signal Vgsl to the isolated flyback converter circuit 100 .

[0078] In one embodiment of a transistor drive control circuit, the drive current control unit 200 determines the operating state of transistor Q based on the feedback signal VFB. When detecting that transistor Q is operating in the amplification region, the drive current control unit 200 generates a forced shutdown signal Vgsl in advance, thereby closing the first switch S1 and short-circuiting the base and emitter of transistor Q, thereby forcibly shutting down transistor Q. Simultaneously, the drive current control unit 200 controls the amplitude of the drive current signal Ibase of transistor Q to increase by a certain amplitude variation ΔI during subsequent switching cycles. Furthermore, this embodiment determines that transistor Q is operating in the amplification region based on the fact that the feedback signal VFB rises from a negative value and exceeds a third voltage threshold V3 before the forced shutdown of transistor Q occurs.

[0079] Attachment Figure 9 FIG. 4 is a timing diagram of various signals in the embodiment of the transistor drive control circuit during normal operation.

[0080] The present invention discloses a transistor drive control method, which comprises the following steps during normal operation:

[0081] Step 1: As attached Figure 9 As shown, in the current cycle, the transistor Q is driven by the first driving current I1, thereby controlling the transistor Q to be turned on, and the current flowing through the transistor Q begins to increase; the feedback signal VFB drops to a fourth voltage.

[0082] Specifically, at the first moment t1, the driving current control unit 200 controls the forced shutdown signal Vgsl to change from high to low, so that the first switch S1 is turned off. At this time, the driving current signal Ibase increases from zero to the first driving current I1. The transistor Q starts to conduct, and the feedback signal VFB starts to decrease. When the feedback signal VFB drops to the fourth voltage V4, the current flowing through the transistor Q begins to increase linearly, as shown in the attached figure. Figure 9 As shown, the sampling signal Vcs also increases linearly. The fourth voltage V4 is a negative value.

[0083] Step 2: As attached Figure 9 As shown, when the current flowing through transistor Q increases to the first sampling threshold, the driving current signal Ibase is controlled to drop to the set threshold; the set threshold in this embodiment is zero. The first sampling threshold in this embodiment is represented by the first voltage threshold V1.

[0084] Specifically, at the second time t2, when the sampling signal Vcs rises and reaches the first voltage threshold V1, the drive current control unit 200 triggers the pre-shutdown condition, causing the drive current signal Ibase output by the drive terminal P3 to decrease from the first drive current I1 to zero. However, since the transistor Q does not turn off immediately at this time, due to the "current tailing effect", the current flowing through the transistor Q still exists, and therefore the sampling signal Vcs continues to rise.

[0085] Step 3: As attached Figure 9 As shown, when the current flowing through transistor Q increases to the second sampling threshold, the base and emitter of transistor Q are controlled to be short-circuited, and transistor Q is turned off. In this embodiment, the second sampling threshold is represented by a second voltage threshold V2.

[0086] Specifically, at the third time t3, when the sampling signal Vcs continues to rise and reaches the second voltage threshold V2, the driving control unit triggers the forced shutdown condition, causing the forced shutdown signal Vgsl output by the first switch control terminal P2 to change from low to high, turning on the first switch S1 and short-circuiting the base and emitter of the transistor Q. The transistor Q begins to turn off, and the feedback signal VFB starts to rise from a negative value and reaches the fifth voltage V5.

[0087] During the process from the first moment t1 to the third moment t3 , the transistor Q is always in a saturation state under normal working conditions. Therefore, in this embodiment, the feedback signal VFB is always maintained at a negative voltage under normal working conditions.

[0088] Attachment Figure 10 1 is a timing diagram of various signals when the transistor Q enters the amplification region in the embodiment of the transistor drive control circuit.

[0089] The present invention also discloses another transistor drive control method, which includes the following steps:

[0090] Step 1: As attached Figure 10 As shown, in the current cycle, the transistor Q is driven by the first driving current I1, thereby controlling the transistor Q to be turned on, and the current flowing through the transistor Q begins to increase; the feedback signal VFB drops to the fourth voltage V4.

[0091] Specifically, at the first moment t1, the driving current control unit 200 controls the forced shutdown signal Vgsl to change from high to low, so that the first switch S1 is turned off. At this time, the driving current signal Ibase increases from zero to the first driving current I1. The transistor Q starts to conduct, and the feedback signal VFB starts to decrease. When the feedback signal VFB drops to the fourth voltage V4, the current flowing through the transistor Q begins to increase linearly, as shown in the attached figure. Figure 10 As shown, the sampling signal Vcs also increases linearly. The fourth voltage V4 is a negative value.

[0092] Step 2: As attached Figure 10 As shown, when the current flowing through transistor Q increases to the first sampling threshold, the driving current signal Ibase is controlled to drop to the set threshold; the set threshold in this embodiment is zero. The first sampling threshold in this embodiment is represented by the first voltage threshold V1.

[0093] Specifically, at the second time t2, when the sampling signal Vcs rises and reaches the first voltage threshold V1, the drive current control unit 200 triggers the pre-shutdown condition, causing the drive current signal Ibase output by the drive terminal P3 to decrease from the first drive current I1 to zero. However, since the transistor Q does not turn off immediately at this time, due to the "current tailing effect", the current flowing through the transistor Q still exists, and therefore the sampling signal Vcs continues to rise.

[0094] Step 3: As attached Figure 10 As shown, when the current flowing through transistor Q has not increased to the second sampling threshold, but the feedback signal VFB has increased and exceeded the third sampling threshold, the base and emitter of transistor Q are controlled to be short-circuited, and transistor Q is turned off; the second sampling threshold is greater than the first sampling threshold. In this embodiment, the second sampling threshold is represented by the second voltage threshold V2, and the third sampling threshold is represented by the third voltage threshold V3.

[0095] Specifically, at the third moment t3, when the sampling signal Vcs continues to rise but does not reach the second voltage threshold V2, the feedback signal VFB has begun to increase, and when the feedback signal VFB rises and exceeds the third voltage threshold V3, the driving current control unit 200 obtains a prompt that the transistor Q is operating in the amplification area, and the driving current control unit 200 immediately controls the first switch tube control terminal P2 to output the forced shutdown signal Vgsl from low to high, thereby controlling the first switch tube S1 to turn on, so that the base of the transistor Q and the emitter of the transistor Q are short-circuited, thereby achieving forced shutdown of the transistor Q.

[0096] Step 4: As attached Figure 10 As shown, in the next cycle, the transistor Q is driven by the second driving current V2, and the second driving current I2 is greater than the first driving current I1.

[0097] Specifically, at the fourth moment t4, when the base of the transistor Q in the next cycle obtains the driving current signal Ibase again, the driving current control unit 200 controls the amplitude of the driving current signal Ibase output by the driving terminal P3 to increase an amplitude change ΔI, that is, I2=I1+ΔI.

[0098] In the above embodiment, the sixth voltage Vce between the collector and emitter of the transistor Q is represented by the feedback signal VFB on the feedback circuit 130 through the transformer T. The operating state of the transistor Q is detected in real time by the change of the feedback signal VFB. Once it is detected that the transistor Q enters the amplification region, the "forced shutdown" action is performed in advance, that is, the first switch S1 is controlled to be closed, so that the base and emitter of the transistor Q are short-circuited and grounded, thereby achieving immediate shutdown of the transistor Q and controlling the amplitude of the driving current signal Ibase of the transistor Q in the next cycle to increase.

[0099] The above embodiment ensures that the driving current signal Ibase of the next cycle is sufficient, thereby preventing the transistor Q from entering the amplification region before forced shutdown due to insufficient driving current, thereby reducing the risk of a sharp increase in the loss of the transistor Q, protecting the transistor Q, and reducing the possibility of damage to the transistor Q.

[0100] In addition, since the above embodiment makes the driving current signal Ibase of the next cycle variable, the applicable range is widened. When the operating temperature of the transistor Q varies widely or the power varies, a driving current signal Ibase that matches the actual power can be provided to the transistor Q, thereby optimizing the operating efficiency and temperature rise effect of the transistor Q.

[0101] The present invention also discloses an embodiment of a transistor drive system, which is a system adopting the embodiment of the transistor drive control circuit disclosed above. The system also has the advantages of the embodiment of the transistor drive control circuit disclosed above in terms of transistor drive control.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0103] In short, the above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the patent of the present invention.

Claims

1. A transistor drive control circuit, characterized in that: It includes a driving current control unit coupled to the triode; the driving current control unit Used to output a driving current signal to drive the transistor, and used to determine the working state of the transistor according to the obtained signal fed back by the transistor, and to forcibly shut down the transistor or maintain the driving action according to the working state; when it is determined that the transistor is working in the amplification region, the driving current control unit forcibly shuts down the transistor; The driving current control unit is further configured to control the amplitude of the driving current signal to increase by an amplitude variation in the next cycle after detecting that the transistor is in the amplification region in the current cycle.

2. The transistor drive control circuit according to claim 1, characterized in that: The driving current control unit includes: A driving module, configured to generate the driving current signal for driving the transistor; A sampling module, used to obtain a sampling signal used to represent the current flowing through the transistor; A shutdown module, used for generating a forced shutdown signal for short-circuiting the base and emitter of the transistor; A feedback module, used to obtain a feedback signal for determining the working state of the transistor; The sampling module and the feedback module are both coupled to the driving module; the driving module outputs the driving current signal according to the sampling signal and the feedback signal, and adjusts the amplitude of the driving current signal; The sampling module and the feedback module are both coupled to the shutdown module; the shutdown module outputs the forced shutdown signal according to the sampling signal and the feedback signal.

3. The transistor drive control circuit according to claim 2, characterized in that: The device further includes an isolated flyback converter circuit coupled to the drive current control unit, the isolated flyback converter circuit being configured to obtain the drive current signal and the forced shutdown signal from the drive current control unit to control the transistor, and to provide the sampling signal to the drive current control unit; The isolated flyback converter circuit includes a feedback circuit; The feedback circuit is coupled to the driving current control unit and is configured to provide the feedback signal to the driving current control unit.

4. The transistor drive control circuit according to claim 3, characterized in that: The isolated flyback converter circuit further includes a sampling circuit; the sampling circuit is used to generate the sampling signal representing the current flowing through the transistor; The driving current control unit determines the working state of the transistor according to the sampling signal and the feedback signal.

5. The transistor drive control circuit according to claim 4, characterized in that: When the driving current control unit detects that the sampling signal increases to a first sampling threshold, the driving current control unit controls the driving current signal to decrease to a set threshold.

6. The transistor drive control circuit according to claim 5, characterized in that: When the driving current control unit detects that the sampling signal increases to a second sampling threshold, the driving current control unit controls the base and emitter of the transistor to be short-circuited, and the transistor is turned off; The second sampling threshold is greater than the first sampling threshold.

7. The transistor drive control circuit according to claim 6, characterized in that: The driving current control unit determines that the transistor enters the amplification region when detecting that the sampling signal has not increased to the second sampling threshold but the feedback signal has increased and exceeded the third voltage threshold.

8. The transistor drive control circuit according to claim 7, characterized in that: A first switch tube is electrically connected between the base of the transistor and the emitter of the transistor; The first switch tube in the on state short-circuits the base of the transistor and the emitter of the transistor.

9. The transistor drive control circuit according to claim 8, characterized in that: The sampling circuit includes a sampling resistor, the emitter of the transistor is electrically connected to one end of the sampling resistor, and the other end of the sampling resistor is grounded; The feedback circuit includes a first resistor and a second resistor connected in series, and a voltage obtained by series voltage division across the second resistor is the feedback signal.

10. The transistor drive control circuit according to claim 9, characterized in that: The driving current control unit includes: a driving end coupled to the driving module, the driving end being electrically connected to the base of the transistor and outputting the driving current signal to the base of the transistor; a sampling terminal coupled to the sampling module, the sampling terminal being electrically connected between the emitter of the transistor and the sampling resistor, and acquiring the voltage across the sampling resistor as the sampling signal; a first switch control terminal coupled to the shutdown module, the first switch control terminal being coupled to the first switch and controlling the first switch by outputting the forced shutdown signal to the first switch; A feedback terminal coupled to the feedback module is electrically connected between the first resistor and the second resistor, and obtains a voltage across the second resistor as the feedback signal.

11. A transistor driving system, characterized in that: The invention comprises the transistor drive control circuit according to any one of claims 1 to 10.

12. A transistor drive control method, characterized in that: The following steps are involved: In the current cycle, the transistor is driven with the first driving current, thereby controlling the transistor to be turned on, and the current flowing through the transistor begins to increase; When the current flowing through the transistor increases to a first sampling threshold, controlling the driving current signal to decrease to a set threshold; as well as When the current flowing through the transistor has not increased to the second sampling threshold, but the feedback signal used to determine the working state of the transistor has increased and exceeded the third voltage threshold, the base and emitter of the transistor are controlled to be short-circuited, and the transistor is turned off; the second sampling threshold is greater than the first sampling threshold; In the next cycle, the transistor is driven with a second driving current, where the second driving current is greater than the first driving current.

13. A transistor drive control method according to claim 12, characterized in that: When the current flowing through the transistor increases to a second sampling threshold, the base and emitter of the transistor are controlled to be short-circuited, thereby controlling the transistor to be turned off.

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