An adaptive drive circuit

Abstract

The application discloses an adaptive driving circuit, which comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor and a C1 capacitor, the gate of the second transistor is connected with a pre-protection driving signal and the gate of the first transistor, the drain of the third transistor is connected with the source of the second transistor, and the C1 capacitor is connected between a post-protection driving signal and a module ground; the gate of the fourth transistor is connected with the pre-protection driving signal, and the drain is connected with the post-protection driving signal; the drain of the fifth transistor is connected with the source of the sixth transistor, and the adaptive driving circuit provided by the application changes the loop impedance size through the state switching between transistors, simultaneously realizes work and shutdown through the signal control of the driving structure, improves the ringing phenomenon generated when the signal flips at high frequency, simultaneously provides a current discharge path, and guarantees the stability of the circuit when the signal rapidly changes.

Description

Technical Field

[0001] This invention relates to the field of integrated circuits, and more specifically to an adaptive driving circuit. Background Technology

[0002] With the vigorous development of electronic and electrical technology, electronic products are being used more and more widely in daily life, and different types of power supply technologies are becoming more and more mature. Under the condition of realizing functions, they are developing towards smaller size, stronger performance and lower power consumption.

[0003] Switching power supplies are the most common DC-to-DC power supply applications. However, traditional Schottky diode rectification methods can no longer meet the requirements for high efficiency. The synchronous rectification technology that uses metal-oxide-semiconductor field-effect transistors (MOSFETs) with extremely low on-resistance to replace Schottky diodes is becoming increasingly common. This can reduce converter losses and improve efficiency. MOSFETs are divided into PMOS (P-channel) and NMOS (N-channel) transistors, which belong to the insulated-gate field-effect transistor category.

[0004] In switching power supply circuits, the printed circuit board (PCB) traces between the chip's decoupling capacitors and power pins, the PCB traces between the chip's power pins, and the bonding wires between the chip's power pins and the internal silicon die can be considered equivalent to a parasitic inductance. When the power MOSFET is off, parasitic capacitance exists between each pair of electrodes. These parasitic inductances (represented by the letter L) and capacitances (represented by the letter C) constitute an LC resonant circuit. Typically, to improve circuit efficiency, the impedance of the MOSFET is made relatively small, meaning the damping coefficient of the resonant circuit may be very small. This results in relatively large ringing during pulse width modulation (PWM) switching.

[0005] In circuits, ringing often causes various problems, leading to malfunctions. In signal loops, ringing causes signal distortion and introduces noise. Furthermore, the voltage spikes caused by ringing can threaten devices; voltage spikes exceeding the device's maximum allowable voltage can damage it. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an adaptive drive circuit. An effective means of reducing ringing is to add a resistor to the circuit. The resistor provides damping, which effectively reduces the ringing amplitude and shortens the oscillation time without affecting the circuit speed. This circuit controls the operating states of the first to sixth transistors via control signals, thereby affecting the impedance of the upper and lower loops. This improves the oscillations generated during signal switching at high frequencies and provides a current discharge path, ensuring the circuit's stability during rapid signal changes.

[0007] The present invention adopts the following technical solution.

[0008] An adaptive driving circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. The gate of the first transistor is connected to the driving signal before protection, the drain is connected to the driving signal after protection, and the source is connected to the internal potential of the module. The gate of the second transistor is connected to both the driving signal before protection and the gate of the first transistor, and the drain is connected to the driving signal after protection. The gate of the third transistor is connected to the driving signal after protection, the drain is connected to the source of the second transistor, and the source is connected to the internal potential of the module. The gate of the fourth transistor is connected to the driving signal before protection, the source is connected to an internal power supply, and the drain is connected to the driving signal after protection. The gate of the fifth transistor is connected to the driving signal after protection, the source is connected to an internal power supply, and the drain is connected to the source of the sixth transistor. The gate of the sixth transistor is connected to the driving signal before protection, the source is connected to the drain of the fifth transistor, and the drain is connected to the driving signal after protection.

[0009] Preferably, it also includes a C1 capacitor; the C1 capacitor is connected between the protected drive signal and the module ground.

[0010] Preferably, the driving signals for the gates of the first transistor, the third transistor, the fourth transistor, and the fifth transistor are the same signal.

[0011] Preferably, the fifth transistor and the sixth transistor have the same size, but the fifth transistor is larger than the fourth transistor; the second transistor and the third transistor have the same size, but the second transistor is larger than the first transistor.

[0012] Preferably, the first, second, third, fourth, fifth, and sixth transistors operate or turn off depending on the input signal.

[0013] Preferably, when the drive signal switches from high level to low level, the first transistor, the second transistor, and the third transistor provide protection; when the drive signal switches from low level to high level, the fourth transistor, the fifth transistor, and the sixth transistor provide protection.

[0014] Preferably, it further includes a first branch and a second branch; the first branch is a path from Vdd to the source of the first transistor, from the drain of the first transistor to the drain of the fourth transistor, and from the source of the fourth transistor to Vss; the second branch is a path from Vdd to the source of the second transistor, from the drain of the second transistor to the source of the third transistor, from the drain of the third transistor to the drain of the fifth transistor, from the source of the fifth transistor to the drain of the sixth transistor, and from the source of the sixth transistor to Vss.

[0015] Preferably, the first transistor, second transistor, third transistor, fourth transistor, fifth transistor, and sixth transistor work together during signal conversion. When the first branch is open, the second branch is not open. During operation, the increased circuit impedance leads to an increase in the damping coefficient, thereby reducing ringing.

[0016] Preferably, during the process of the drive signal switching from low level to high level, when the drive signal is low level, the first and third transistors are working, the fourth and fifth transistors are off, the second transistor is off, and the sixth transistor is working. At this time, no current flows through the first branch and the second branch. When the signal is officially established, the first branch becomes the only path and current flows through it. The sixth transistor is off, and the second branch is not connected.

[0017] Preferably, when the drive signal switches from high level to low level, the fourth transistor, the fifth transistor, and the sixth transistor are turned off, and the transistor in the first branch is activated.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. In this invention, the switching of two branch transistors can be controlled according to the high and low level switching of the drive signal. By setting a reasonable transistor size, the circuit damping coefficient can be increased by controlling two paths with different impedances, thereby improving the ringing caused by current oscillation due to parasitic inductance and ensuring that the circuit logic correctly determines the switching state of the power transistor.

[0020] 2. In this invention, the parasitic inductance between the power MOS and the on-chip ground potential forms a charge discharge path through the parasitic capacitance between the MOS gate and source and the branch where the fifth and sixth transistors are located, thus avoiding the accumulation of charge that causes fluctuations in the chip ground potential and leads to logic uncertainty.

[0021] 3. By changing the state of transistors to change the circuit impedance, and using signal control of the drive structure to achieve operation and shutdown, the ringing phenomenon caused by signal flipping at high frequencies is improved, and a current discharge path is provided to ensure the stability of the circuit when the signal changes rapidly.

[0022] 4. This invention reduces the size of the chip control circuit and saves area without requiring additional control circuitry to ensure stable drive signals. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the circuit structure of an adaptive driving circuit in this invention;

[0024] Figure 2 This is a comparison diagram of the effect of the adaptive driving circuit before and after improvement in the driving signal in this invention;

[0025] In the picture:

[0026] 1-First branch; 2-Second branch; 3-First transistor; 4-Second transistor; 5-Third transistor; 6-Fourth transistor; 7-Fifth transistor; 8-Sixth transistor; 9-C1 capacitor. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0028] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present application.

[0029] Figure 1 The present invention provides an adaptive driving circuit structure diagram, which includes a first transistor 3, a second transistor 4, a third transistor 5, a fourth transistor 6, a fifth transistor 7, a sixth transistor 8, and a capacitor C1 9.

[0030] The gate of the first transistor 3 is connected to the drive signal before protection, the drain is connected to the drive signal after protection, and the source is connected to the ground potential of the module.

[0031] The gate of the second transistor 4 is connected to the drive signal before protection and the gate of the first transistor 3, the drain is connected to the drive signal after protection, and the source is connected to the drain of the third transistor.

[0032] The gate of the third transistor is connected to the protected drive signal, the drain is connected to the source of the second transistor 4, and the source is connected to the internal potential of the module.

[0033] C1 capacitor 9 is a large capacitor between the protected drive signal and the module ground.

[0034] The gate of the fourth transistor 6 is connected to the drive signal before protection, the source is connected to the internal power supply, and the drain is connected to the drive signal after protection.

[0035] The gate of the fifth transistor 7 is connected to the protected drive signal, the source is connected to the internal power supply, and the drain is connected to the source of the sixth transistor 8.

[0036] The gate of the sixth transistor 8 is connected to the drive signal before protection, the source is connected to the drain of the fifth transistor 7, and the drain is connected to the drive signal after protection.

[0037] The drive signals for the gates of the first transistor 3, the third transistor 5, the fourth transistor 6, and the fifth transistor 7 are the same.

[0038] The fourth transistor 6, the fifth transistor 7, and the sixth transistor 8 have a corresponding ratio. The fifth transistor 7 and the sixth transistor 8 are of equal size, but larger than the fourth transistor 6. The second transistor 4 and the third transistor 5 are of equal size, but larger than the first transistor 3.

[0039] The damping coefficient is commonly used to represent circuit characteristics, and the formula is:

[0040] Damping coefficient of LC resonant circuit:

[0041] Where f0 is the resonant frequency, L is the parasitic inductance, C is the parasitic capacitance, and R is the equivalent resistance of the series resonance.

[0042] An LC resonant circuit with a damping coefficient of 1 is critically damped and has no ringing. An LC resonant circuit with a damping coefficient less than 1 is underdamped and has ringing. An LC resonant circuit with a damping coefficient greater than 1 is overdamped. Step signal jumps are not accompanied by ringing, but it takes a long time to stabilize to the final value.

[0043] When the values ​​of parasitic capacitance and inductance in the circuit remain constant, the damping coefficient of the LC resonant circuit can be adjusted by changing the resistance of the circuit through the size of the transistor.

[0044] Transistors 3, 4, 5, 6, 7, and 8 operate or turn off depending on the input signal. When the signal switches from high to low, transistors 3, 4, and 5 provide protection; when the signal switches from low to high, transistors 6, 7, and 8 provide protection. The six transistors work together during signal transitions. When branch 1 is active, branch 2 is inactive. This increased circuit impedance leads to a higher damping coefficient, reducing ringing.

[0045] The first branch is Vdd to the source of the first transistor 3, the drain of the first transistor 3 to the drain of the fourth transistor 6, and the source of the fourth transistor 6 to the Vss path; the second branch is Vdd to the source of the second transistor 4, the drain of the second transistor 4 to the source of the third transistor 5, the drain of the third transistor 5 to the drain of the fifth transistor 7, the source of the fifth transistor 7 to the drain of the sixth transistor 8, and the source of the sixth transistor 8 to the Vss path.

[0046] In a preferred but non-limiting embodiment, the drive signal after the protection circuit is input through the gates of the fourth transistor 6 and the fifth transistor 7, and the gate of the sixth transistor 8 is connected to LG. LG is the low-side power MOS switch control signal, which is output after the protection circuit is activated, and has driving capability.

[0047] During the transition from low to high level of the drive signal, when the drive signal is low, transistors 3 and 5 are active, transistors 6 and 7 are off, transistor 4 is off, and transistor 8 is active. At this time, no current flows through either branch 1 or branch 2. When the drive signal changes from low to high, transistors 6 and 7 are active, and transistor 8 is off. During the drive signal transition, there may be a moment when transistors 6, 7, and 6 are active simultaneously. Most of the current flows to chip ground through branch 2, and a small portion flows to chip ground through branch 1. The charge stored in the parasitic inductance is discharged through branch 2 at this time. Once the signal is established, branch 1 becomes the only path, and current flows through it. Transistor 8 is off, and branch 2 is closed. When branch 1 is active, its impedance is greater than when branch 2 is active. Therefore, after the signal stabilizes, compared to the drive circuit without this invention, the higher impedance increases the damping coefficient of the LC resonant circuit, improving the ringing during the transition from low to high level.

[0048] When the drive signal switches from high to low, transistors 6 (fourth), 7 (fifth), and 8 (sixth) disconnect. At this time, the transistor in branch 1 operates, and its impedance is greater than the impedance of branch 1 and branch 2 operating simultaneously. This increases the damping coefficient of the LC resonant circuit, improving the ringing during the signal transition from high to low. The improvement in drive signal performance is as follows: Figure 2 As shown.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] 1. In this invention, the switching of two branch transistors can be controlled according to the high and low level switching of the drive signal. By setting a reasonable transistor size, the circuit damping coefficient can be increased by controlling two paths with different impedances, thereby improving the ringing caused by current oscillation due to parasitic inductance and ensuring that the circuit logic correctly determines the switching state of the power transistor.

[0051] 2. In this invention, the parasitic inductance between the power MOS and the on-chip ground potential forms a charge discharge path through the parasitic capacitance between the MOS gate and source and the branch where the fifth and sixth transistors are located, thus avoiding the accumulation of charge that causes fluctuations in the chip ground potential and leads to logic uncertainty.

[0052] 3. By changing the state of transistors to change the circuit impedance, and using signal control of the drive structure to achieve operation and shutdown, the ringing phenomenon caused by signal flipping at high frequencies is improved, and a current discharge path is provided to ensure the stability of the circuit when the signal changes rapidly.

[0053] 4. This invention reduces the size of the chip control circuit and saves area without requiring additional control circuitry to ensure stable drive signals.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. An adaptive drive circuit comprising a first transistor (3), a second transistor (4), a third transistor (5), a fourth transistor (6), a fifth transistor (7) and a sixth transistor (8), characterized in that: a gate of the first transistor (3) is connected to a drive signal before protection, a drain is connected to a drive signal after protection, and a source is connected to a ground potential in a module; a gate of the second transistor (4) is connected to the drive signal before protection and a gate of the first transistor (3), and a drain is connected to the drive signal after protection; a gate of the third transistor (5) is connected to the drive signal after protection, a drain is connected to a source of the second transistor (4), and a source is connected to the ground potential in the module; a gate of the fourth transistor (6) is connected to the drive signal before protection, a source is connected to an internal power supply, and a drain is connected to the drive signal after protection; a gate of the fifth transistor (7) is connected to the drive signal after protection, a source is connected to the internal power supply, and a drain is connected to a source of the sixth transistor (8); a gate of the sixth transistor (8) is connected to the drive signal before protection, a source is connected to a drain of the fifth transistor, and a drain is connected to the drive signal after protection.

2. The adaptive drive circuit according to claim 1, characterized in that: it further comprises a C1 capacitor (9); the C1 capacitor (9) is connected between the drive signal after protection and the ground of the module.

3. The adaptive drive circuit according to claim 1, characterized in that: the drive signals input to the gates of the first transistor (3), the third transistor (5), the fourth transistor (6) and the fifth transistor (7) are the same signals.

4. The adaptive drive circuit according to claim 1, characterized in that: the fifth transistor (7) and the sixth transistor (8) have the same size, and the size is greater than that of the fourth transistor (6); the second transistor (4) and the third transistor (5) have the same size, and the size is greater than that of the first transistor (3).

5. The adaptive drive circuit according to claim 1, characterized in that: the first transistor (3), the second transistor (4), the third transistor (5), the fourth transistor (6), the fifth transistor (7) and the sixth transistor (8) work or are turned off according to the input signal.

6. The adaptive drive circuit according to claim 1, characterized in that: when the drive signal is switched from high level to low level, the first transistor (3), the second transistor (4) and the third transistor (5) play a protection role; when the drive signal is switched from low level to high level, the fourth transistor (6), the fifth transistor (7) and the sixth transistor (8) play a protection role.

7. The adaptive drive circuit according to claim 1, characterized in that: it further comprises a first branch (1) and a second branch (2); the first branch is a path from Vdd to a source of the first transistor (3), from a drain of the first transistor (3) to a drain of the fourth transistor (6), and from a source of the fourth transistor (6) to Vss. The second branch is Vdd to the source of the second transistor (4), the drain of the second transistor (4) to the source of the third transistor (5), the drain of the third transistor (5) to the drain of the fifth transistor (7), the source of the fifth transistor (7) to the drain of the sixth transistor (8), and the source of the sixth transistor (8) to the Vss path.

8. The adaptive drive circuit of claim 7, wherein: The first transistor (3), the second transistor (4), the third transistor (5), the fourth transistor (6), the fifth transistor (7), and the sixth transistor (8) work together when the signal is transformed, the first branch (1) is on and the second branch (2) is off, which increases the loop impedance and the damping coefficient, and reduces the ringing.

9. The use method of the adaptive drive circuit of claim 7, wherein: When the driving signal is switched from low to high, when the driving signal is low, the first transistor (3) and the third transistor (5) work, the fourth transistor (6) and the fifth transistor (7) are off, the second transistor (4) is off, and the sixth transistor (8) works, at this time, no current flows through the first branch (1) and the second branch (2); When the signal is established, the first branch (1) is the only path, current flows through, the sixth transistor (8) is off, and the second branch (2) is not on.

10. The use method of the adaptive drive circuit of claim 8, wherein: When the driving signal is switched from high to low, the fourth transistor (6), the fifth transistor (7), and the sixth transistor (8) are off, at this time, the transistors in the first branch (1) work.

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