Threshold detection circuit, power circuit, and half-bridge circuit

Abstract

The invention provides a threshold detection circuit which is characterized in that a source electrode of a first PMOS (P-channel Metal Oxide Semiconductor) tube of the circuit is coupled to a high-voltage power supply port, a drain electrode of the first PMOS tube is connected to a low-voltage port sequentially through a first resistor, a second resistor and a second NMOS (N-channel Metal Oxide Semiconductor) tube, a third PMOS tube is coupled to two ends of the first resistor, a grid electrode of the third PMOS tube is connected to a drain electrode of the second NMOS tube through a first phase inverter, and a second phase inverter is connected to a drain electrode of the second NMOS tube. The shaping module is used for outputting a judgment signal based on the voltage of the drain electrode of the second NMOS tube; the first end of the quiescent current control module and the grid electrode of the second NMOS tube receive the voltage of the grid electrode of the power tube, and the second end of the quiescent current control module is coupled to the grid electrode of the first PMOS tube and used for controlling the first PMOS tube to be switched on or switched off based on the voltage of the grid electrode of the power tube. The on-off state of the power tube is accurately obtained through on-off of the third PMOS tube, the quiescent current control module is used for reducing the time when quiescent current exists in the circuit, and power consumption of the circuit is reduced.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular to a threshold detection circuit, a power circuit and a half-bridge circuit. Background Art

[0002] In the power circuit, in order to ensure the stable operation of the circuit, the on and off state of the power tube must be accurately controlled. The on-resistance of the power tube is in the milliohm range. In practical applications, due to factors such as the phase mismatch of the gate drive signal and the excessive size of the power tube, it is easy for the power tube to fail to be completely turned off. In the drive of the half-bridge structure or H-bridge structure, this problem may cause the high-side power tube and the low-side power tube to be turned on at the same time, posing the risk of burning the power device.

[0003] In order to avoid such problems, traditional control methods usually adopt setting a reasonable fixed dead time to ensure the safe switching of the power tube. However, this method also has certain shortcomings. Affected by factors such as temperature and process, the actual dead time may deviate from the theoretical design value, resulting in the fixed dead time being too large or too small. The longer the dead time, the greater the nonlinear distortion in the circuit. If the dead time is too short, it will not only cause current overshoot at the output point, but also may still cause the problem of simultaneous conduction of the power tubes.

[0004] Therefore, how to accurately obtain the current on-off state of the power tube has become a technical problem that urgently needs to be solved in the industry. Summary of the invention

[0005] The present invention provides a threshold detection circuit, a power circuit and a half-bridge circuit, which solve the technical problem of how to accurately obtain the current on-off state of a power tube.

[0006] According to a first aspect of the present invention, an embodiment of the present invention provides a threshold detection circuit for determining whether a power tube is turned off or on, the circuit comprising a first PMOS tube, a second NMOS tube, a third PMOS tube, a first resistor, a second resistor, a shaping module and a static current control module; The source of the first PMOS tube is coupled to the high voltage power supply port, and the drain thereof is coupled to the first end of the first resistor, the second end of the first resistor is coupled to the first end of the second resistor, the second end of the second resistor is respectively coupled to the drain of the second NMOS tube and the input end of the first inverter, the output end of the first inverter is coupled to the gate of the third PMOS tube, the source and drain of the third PMOS tube are respectively coupled to the first end and the second end of the first resistor, the drain of the second NMOS tube is coupled to the shaping module, the source of the second NMOS tube is connected to the low voltage port, and the resistance value of the first resistor is greater than the resistance value of the second resistor; The first end of the static current control module and the gate of the second NMOS tube both receive the voltage of the gate of the power tube, and the second end of the static current control module is coupled to the gate of the first PMOS tube; wherein: The static current control module is configured to: control the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube, so as to control the static current of the threshold detection circuit; The shaping module is configured to output a judgment signal based on the voltage of the drain of the second NMOS tube, wherein the judgment signal includes on-off state information of the power tube.

[0007] Optionally, the method of controlling the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube to control the static current of the threshold detection circuit includes: When the voltage of the gate of the power tube rises and the voltage of the gate of the power tube is greater than a first set voltage, the first PMOS tube is controlled to be cut off, so as to control the static current of the threshold detection circuit to be 0; When the voltage of the gate of the power tube decreases and the voltage of the gate of the power tube is less than a second set voltage, the first PMOS tube is controlled to be turned on.

[0008] Optionally, the first set voltage is greater than the first flip voltage, the first flip voltage is the voltage of the power tube gate corresponding to when the judgment signal is in a downward level flip, and the second set voltage is greater than the second flip voltage, the second flip voltage is the voltage of the power tube gate corresponding to when the judgment signal is in an upward level flip.

[0009] Optionally, the static current control module includes a first inverting Schmitt trigger and a second inverter; The input end of the first inverting Schmitt trigger receives the voltage of the gate of the power tube, and the output end thereof is coupled to the gate of the first PMOS tube through the second inverter; The upward threshold voltage of the first inverting Schmitt trigger is the first set voltage, and the downward threshold voltage is the second set voltage.

[0010] Optionally, the static current control module includes a second Schmitt trigger; The input end of the second Schmitt trigger receives the voltage of the gate of the power tube, and the output end thereof is coupled to the gate of the first PMOS tube; The upward threshold voltage of the second Schmitt trigger is the first set voltage, and the downward threshold voltage is the second set voltage.

[0011] Optionally, the static current control module includes a first buffer, a filter resistor and a filter capacitor; The input end of the first buffer receives the voltage of the gate of the power tube, and the output end thereof is coupled to the first end of the filter resistor. The second end of the filter resistor is respectively coupled to the gate of the first PMOS tube and the first end of the filter capacitor, and the second end of the filter capacitor is grounded.

[0012] Optionally, the shaping module includes a second buffer; The first end of the second buffer is coupled to the drain of the second NMOS tube, and the second end of the second buffer is used to output the determination signal.

[0013] Optionally, the shaping module includes a third Schmitt trigger; A first end of the third Schmitt trigger is coupled to the drain of the second NMOS tube, and a second end of the third Schmitt trigger is used to output the determination signal.

[0014] Optionally, a resistance ratio of the first resistor to the second resistor is greater than or equal to 10.

[0015] According to a second aspect of the present invention, an embodiment of the present invention provides a power circuit, comprising a power tube, a first control module, and a threshold detection circuit as described in any one of the first aspects of the present invention; The first end of the control module is coupled to the gate of the power tube, the second end thereof is coupled to the output end of the threshold detection circuit, and the third end thereof receives a gate control signal; The input end of the threshold detection circuit is coupled to the gate of the power tube; The first control module is configured to control the on and off of the power tube based on the judgment signal and the gate control signal.

[0016] According to a second aspect of the present invention, an embodiment of the present invention provides a half-bridge circuit, including a high-side power tube, a low-side power tube, a first threshold detection module, a second threshold detection module and a second control module, wherein the first threshold detection module and the second threshold detection module both include the threshold detection circuit according to any one of the first aspects of the present invention; The first end of the high-side power tube is coupled to the high-voltage power supply port, the second end thereof is coupled to the first end of the low-side power tube via a first node, and the second end of the low-side power tube is coupled to the low-voltage port; The power supply end of the first threshold detection module is coupled to the high voltage power supply port, the ground end is coupled to the first node, the input end is coupled to the gate of the high-side power tube, and the output end is coupled to the first input end of the second control module to output a first judgment signal; The power supply end of the second threshold detection module is coupled to the first node, the ground end is coupled to the low voltage port, the input end is coupled to the gate of the low-side power tube, and the output end is coupled to the second input end of the second control module to output a second judgment signal; The third input terminal of the second control module receives the switch tube control signal, the first output terminal thereof is coupled to the gate of the high-side power tube, and the second output terminal thereof is coupled to the gate of the low-side power tube; The second control module is configured as follows: Based on the first judgment signal, the second judgment signal and the switch tube control signal, the on-off of the high-side power tube and the on-off of the low-side power tube are controlled respectively.

[0017] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects: In the threshold detection circuit of the technical solution of the present invention, the source of the first PMOS tube is coupled to the high voltage power supply port, and its drain is connected to the low voltage port through the first resistor, the second resistor and the second NMOS tube in sequence, the third PMOS tube is coupled to the two ends of the first resistor, and its gate is connected to the drain of the second NMOS tube through the first inverter, and the shaping module is used to output a judgment signal based on the voltage of the drain of the second NMOS tube; the first end of the static current control module and the gate of the second NMOS tube both receive the voltage of the gate of the power tube, and the second end of the static current control module is coupled to the gate of the first PMOS tube, which is used to control the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube. The present invention uses the on-off of the third PMOS tube to accurately obtain the on-off state of the power tube, and uses the static current control module to reduce the time when the static current exists in the circuit, thereby reducing the power consumption of the circuit.

[0018] In the power circuit and half-bridge circuit of the technical solution of the present invention, by utilizing the threshold detection circuit provided by the present invention, the on-off state of the power tube can be accurately obtained, thereby realizing automatic adjustment of the dead time to adapt to deviations caused by factors such as temperature process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of an H-bridge circuit of the prior art; Figure 2is a waveform diagram of a gate control signal corresponding to an H-bridge circuit in the prior art; Figure 3 is a schematic structural diagram of a threshold detection circuit provided by an embodiment of the present invention; Figure 4 is corresponding to Figure 3 Working waveform diagram; Figure 5 is a structural schematic diagram of a threshold detection circuit provided by another embodiment of the present invention; Figure 6 is a structural schematic diagram of a threshold detection circuit provided by another embodiment of the present invention; Figure 7 is a structural schematic diagram of a threshold detection circuit provided by yet another embodiment of the present invention; Figure 8 is a schematic structural diagram of a power circuit provided by yet another embodiment of the present invention; Fig. 9 is a structural schematic diagram of a half-bridge circuit provided by yet another embodiment of the present invention; Fig.10 1 is a schematic diagram of the structure of an H-bridge circuit provided in yet another embodiment of the present invention.

[0021] Reference numerals: M1-first PMOS tube; M2-second NMOS tube; M3-the third PMOS tube; M4-power tube; M5-high side power tube; M6- low side power tube; R1-first resistor; R2-second resistor; R3-filter resistor; C1- filter capacitor; INV1-first inverter; INV2 - second inverter; 10-Quiet current control module; 101-first inverting Schmitt trigger; 102-second Schmitt trigger; 103- first buffer; 20-shaping module; 201-third Schmitt trigger; 202-second buffer; 30- first control module; 40-a first threshold detection module; 50-a second threshold detection module; 60- second control module; 70-level shift module; 80-high side driver module; 90- low side driver module; 100-Bootstrap module. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the 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.

[0023] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0025] As described in the background art, it is currently difficult to accurately obtain the current on / off state of the power tube, which will be described in detail below.

[0026] Please refer to Figure 1 , Figure 1 An H-bridge circuit is provided, which includes four power switch tubes, wherein Q1 and Q2 are high-side power tubes driven by a high-side circuit; Q3 and Q4 are low-side power tubes driven by a low-side circuit. By controlling the opening and closing of the high-side and low-side power tubes through a pair of reverse PWM signals, the H-bridge circuit can generate bipolar output voltage and current.

[0027] In practical applications, please refer to Figure 2, the traditional dead time control method usually sets a fixed delay to ensure that the high-side and low-side power tubes are not turned on at the same time, so as to prevent the formation of a low-resistance path between the power supply and the ground, and avoid the large current burning the power device. However, due to changes in temperature, process and other factors, the actual dead time may deviate from the design value. If Figure 1 The H-bridge circuit shown is used in a class D power amplifier. If the fixed dead time is too long, the class D power amplifier will produce greater nonlinear distortion, while if the dead time is too short, it may cause output point voltage overshoot and even cause the high and low side power tubes to be turned on at the same time, posing a risk of burning the device.

[0028] In view of this, an embodiment of the present invention provides a threshold detection circuit, wherein the source of a first PMOS tube is coupled to a high voltage power supply port, the drain of which is sequentially connected to a low voltage port through a first resistor, a second resistor and a second NMOS tube, a third PMOS tube is coupled to both ends of the first resistor, and its gate is connected to the drain of the second NMOS tube through a first inverter, and a shaping module is used to output a judgment signal based on the voltage of the drain of the second NMOS tube; the first end of the static current control module and the gate of the second NMOS tube both receive the voltage of the gate of the power tube, and the second end of the static current control module is coupled to the gate of the first PMOS tube, and is used to control the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube. The present invention uses the on-off of the third PMOS tube to accurately obtain the on-off state of the power tube, and uses the static current control module to reduce the time when the static current exists in the circuit, thereby reducing the power consumption of the circuit.

[0029] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Please refer to Figure 3 , an embodiment of the present invention provides a threshold detection circuit for determining whether a power tube is turned off or on, the circuit comprising a first PMOS tube M1, a second NMOS tube M2, a third PMOS tube M3, a first resistor R1, a second resistor R2, a shaping module 20 and a static current control module 10; The source of the first PMOS tube M1 is coupled to the high voltage power supply port, and the drain thereof is coupled to the first end of the first resistor R1. The second end of the first resistor R1 is coupled to the first end of the second resistor R2. The second end of the second resistor R2 is respectively coupled to the drain of the second NMOS tube M2 and the input end of the first inverter INV1. The output end of the first inverter INV1 is coupled to the gate of the third PMOS tube M3. The source and drain of the third PMOS tube M3 are respectively coupled to the first end and the second end of the first resistor R1. The drain of the second NMOS tube M2 is coupled to the shaping module 20. The source of the second NMOS tube M2 is connected to the low voltage port. The resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2. The first end of the static current control module 10 and the gate of the second NMOS tube M2 both receive the voltage of the power tube gate, and the second end of the static current control module 10 is coupled to the gate of the first PMOS tube M1; wherein: The static current control module 10 is configured to: based on the voltage V G size, controlling the first PMOS tube M1 to be turned on or off, so as to control the static current size of the threshold detection circuit; The shaping module 20 is configured to output a judgment signal based on the voltage of the drain of the second NMOS tube M2 , wherein the judgment signal includes on / off state information of the power tube.

[0031] In a specific implementation, based on the voltage V of the power tube gate G The method of controlling the first PMOS tube M1 to be turned on or off to control the static current size of the threshold detection circuit includes: The voltage V at the gate of the power tube G rises, and the voltage V G When the voltage is greater than the first set voltage, the first PMOS tube M1 is controlled to be turned off, so as to control the static current of the threshold detection circuit to be 0; The voltage V at the gate of the power tube G The voltage V G When the voltage is less than the second set voltage, the first PMOS tube M1 is controlled to be turned on.

[0032] The first setting voltage is greater than the first flip voltage, and the first flip voltage is the voltage V corresponding to the gate of the power tube when the judgment signal is in a downward level flip. G, the second set voltage is greater than the second flip voltage, and the second flip voltage is the voltage V corresponding to the gate of the power tube when the judgment signal is in an upward level flip. G .

[0033] It can be seen that the present invention utilizes the on-off state of the third PMOS tube M3 to accurately obtain the on-off state of the power tube, and utilizes the static current control module 10 to reduce the time when the static current exists in the circuit, thereby reducing the power consumption of the circuit.

[0034] In practical applications, the voltage of the high voltage power supply port of the threshold detection circuit of the present invention depends on the working voltage of the logic control circuit in the circuit, and is generally 5 V. Of course, the present invention is not limited to this, and those skilled in the art can select a suitable voltage.

[0035] Now combined Figure 4 The waveform of Figure 3 The working effect of the circuit shown is explained in Figure 3 In the embodiment, the first PMOS tube M1, the second NMOS tube M2 and the second resistor R2 constitute a flip circuit, and the third PMOS tube M3, the first resistor R1 and the first inverter INV1 constitute a feedback circuit; wherein: V G , which can be understood as the voltage V of the gate of the power tube G The waveform of V1, which can be understood as the first flip voltage; V2, which can be understood as the second flip voltage; V3, which can be understood as the first set voltage; V4, which can be understood as the second set voltage; V FB1 , which can be understood as the waveform of the voltage at the drain of the second NMOS tube M2; V FB2 , which can be understood as the waveform of the judgment signal; I DD , which can be understood as the static current size of the branch where the first PMOS tube M1 and the second NMOS tube M2 are located.

[0036] It can be seen that at the time t0 to t1, the voltage V G Gradually increases, and at time t1, the voltage V G When the threshold voltage Vth of the second NMOS tube M2 is reached, the voltage of the drain of the second NMOS tube M2 starts to decrease (that is, the signal starts to flip); At time t2, the voltage V Grises to the first inversion voltage V1. At this time, due to the first inverter INV1 FB1 The voltage of the third PMOS tube M3 is inverted, so that the third PMOS tube M3 enters the cut-off state, and the first resistor R1 is connected in series with the second resistor R2, which eventually leads to the drain voltage V FB1 is pulled down quickly, and the static current of the threshold detection circuit also drops quickly; At time t3, the voltage V G When the voltage rises to the first set voltage V3, the quiescent current control module 10 controls the first PMOS tube M1 to be turned off, so as to control the quiescent current of the threshold detection circuit to be 0, which is equivalent to the threshold detection circuit stopping working; At time t4, the voltage V G Start to descend; At time t5, the voltage V G is less than the second set voltage V4. At this time, the static current control module 10 controls the first PMOS tube M1 to be turned on, which is equivalent to the threshold detection circuit starting to work; At time t6, the voltage V G In the falling process, the voltage approaches the threshold voltage Vth of the second NMOS tube M2, and the voltage of the drain of the second NMOS tube M2 starts to rise (that is, the signal starts to flip); At time t7, the voltage V G The voltage drops to the second flip voltage V2. At this time, due to the first inverter INV1 FB1 The voltage of the drain of the second NMOS tube M2 is reversed, so that the third PMOS tube M3 enters the on state, the first resistor R1 is short-circuited, and finally the voltage V FB1 is pulled up quickly, and the quiescent current of the threshold detection circuit also rises quickly.

[0037] It can be seen that the present invention utilizes the on-off state of the third PMOS tube M3 to accurately obtain the on-off state of the power tube, and at the time t3 to t5, the circuit has no static current, thereby reducing the power consumption of the entire circuit.

[0038] Please continue to refer to Figure 4 At time t2, it can also be understood that the voltage difference between the voltage of the high voltage power supply port and the voltage output by the first inverter INV1 is greater than or equal to the threshold voltage Vth of the third PMOS. In a preferred embodiment, the voltage V of the gate of the power tube at this time can be G The first inversion voltage V1 is determined.

[0039] Correspondingly, at time t7, it can also be understood that the voltage difference between the voltage of the high voltage power supply port and the voltage output by the first inverter INV1 is less than the threshold voltage Vth of the third PMOS. In a preferred embodiment, the voltage V of the gate of the power tube at this time can be G The second inversion voltage V2 is determined.

[0040] In a specific implementation, the power supply terminal of the first inverter INV1 is coupled to the high voltage power supply port. Of course, the present invention does not limit the connection between the power supply and the ground of the first inverter INV1.

[0041] To achieve the voltage V of the drain of the second NMOS tube M2 FB1 It can be quickly pulled up or down. In a preferred implementation, the resistance ratio of the first resistor R1 to the second resistor R2 is greater than or equal to 10.

[0042] Of course, the present invention is not limited thereto, and those skilled in the art may select the resistance values ​​of the first resistor R1 and the second resistor R2 as required, and may also select the size of the MOS tube as required, and the present invention is not limited thereto.

[0043] The specific structure of the static current control module 10 of the present invention is now further described. In the following figure, the voltage of the high voltage power supply port is the power supply voltage V DD , the voltage of the low voltage port is the power ground voltage.

[0044] The static current control module 10 of the present invention has a hysteresis function. The present invention also sets a corresponding operating voltage range of the threshold detection circuit by setting a first set voltage V3 and a second set voltage V4, thereby reducing the risk of false triggering of the threshold detection circuit.

[0045] In a specific implementation, please refer to Figure 5 , the static current control module 10 includes a first inverting Schmitt trigger 101 and a second inverter INV2; The input terminal of the first inverting Schmitt trigger 101 receives the voltage V of the gate of the power tube. G , an output end of which is coupled to the gate of the first PMOS tube M1 through the second inverter INV2; The upward threshold voltage of the first inverting Schmitt trigger 101 is the first set voltage V3, and the downward threshold voltage is the second set voltage V4.

[0046] In another specific embodiment, please refer to Figure 6, the static current control module 10 includes a second Schmitt trigger 102; The input terminal of the second Schmitt trigger 102 receives the voltage V of the gate of the power tube. G , an output end of which is coupled to the gate of the first PMOS tube M1; The upward threshold voltage of the second Schmitt trigger 102 is the first set voltage V3, and the downward threshold voltage is the second set voltage V4.

[0047] In other embodiments, please refer to Figure 7 , the static current control module 10 includes a first buffer 103, a filter resistor R3 and a filter capacitor C1; The input terminal of the first buffer 103 receives the voltage V of the gate of the power tube. G , an output end of which is coupled to the first end of the filter resistor R3, a second end of the filter resistor R3 is respectively coupled to the gate of the first PMOS tube M1 and the first end of the filter capacitor C1, and a second end of the filter capacitor C1 is grounded.

[0048] The filter resistor R3 and the filter capacitor C1 form a hysteresis circuit, so that the first PMOS switch can be G When the voltage V G It is turned on when it is less than the second set voltage V4.

[0049] Of course, the present invention does not limit the specific circuit structure of the static current control module 10, as long as the voltage V of the gate of the power tube can be obtained G Any circuit with a hysteresis function is within the protection scope of the present invention.

[0050] The specific structure of the shaping module 20 of the present invention is now further described.

[0051] In a specific implementation, please refer to Figure 5 , the shaping module 20 includes a third Schmitt trigger 201; A first terminal of the third Schmitt trigger 201 is coupled to the drain of the second NMOS transistor M2 , and a second terminal thereof is used to output the determination signal.

[0052] In another specific embodiment, please refer to Figure 6 , the shaping module 20 includes a second buffer 202; A first terminal of the second buffer 202 is coupled to the drain of the second NMOS transistor M2 , and a second terminal of the second buffer 202 is used to output the determination signal.

[0053] Of course, the present invention does not limit the specific circuit structure of the shaping module 20. As long as the voltage waveform of the drain of the second NMOS tube M2 can be shaped and a correct judgment signal can be output, it is within the protection scope of the present invention.

[0054] In summary, the present invention sets the source of the first PMOS tube to be coupled to the high voltage power supply port, and the drain thereof is connected to the low voltage port through the first resistor, the second resistor and the second NMOS tube in sequence, the third PMOS tube is coupled to the two ends of the first resistor, and the gate thereof is connected to the drain of the second NMOS tube through the first inverter, and the shaping module is used to output a judgment signal based on the voltage of the drain of the second NMOS tube; the first end of the static current control module and the gate of the second NMOS tube both receive the voltage of the gate of the power tube, and the second end of the static current control module is coupled to the gate of the first PMOS tube, and is used to control the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube. The present invention uses the on-off of the third PMOS tube to accurately obtain the on-off state of the power tube, and uses the static current control module to reduce the time when the static current exists in the circuit, thereby reducing the power consumption of the circuit.

[0055] In addition, the embodiment of the present invention further provides a power circuit, please refer to Figure 8 , comprising a power tube M4, a first control module 30, and a threshold detection circuit as described in any one of the above items; The first end of the control module is coupled to the gate of the power tube M4, the second end thereof is coupled to the output end of the threshold detection circuit, and the third end thereof receives a gate control signal; The input end of the threshold detection circuit is coupled to the gate of the power tube M4; The first control module 30 is configured to control the on and off of the power tube M4 based on the determination signal and the gate control signal.

[0056] Since the threshold detection circuit provided by the present invention can accurately determine the on / off state of the power tube M4, the first control module 30 can automatically adjust the dead time based on the determination signal and the gate control signal to adapt to deviations caused by factors such as temperature and process.

[0057] In practical applications, the power circuit provided by the present invention can be applied in a fully integrated power-stage switch circuit. Of course, the present invention is not limited thereto, and can also be applied in other applications that require accurate acquisition of the state of the power tube.

[0058] In addition, the embodiment of the present invention also provides a half-bridge circuit, please refer to Fig. 9, including a high-side power tube M5, a low-side power tube M6, a first threshold detection module 40, a second threshold detection module 50 and a second control module 60, wherein the first threshold detection module 40 and the second threshold detection module 50 both include the threshold detection circuit as described in any one of the first aspects of the present invention; Fig. 9 In the example of Figure 5 same.

[0059] The first end of the high-side power tube M5 is coupled to the high-voltage power supply port, the second end thereof is coupled to the first end of the low-side power tube M6 through a first node, and the second end of the low-side power tube M6 is coupled to the low-voltage port; The power supply end of the first threshold detection module 40 is coupled to the high voltage power supply port, the ground end is coupled to the first node, the input end is coupled to the gate of the high-side power tube M5, and the output end is coupled to the first input end of the second control module 60 to output a first judgment signal; The power supply terminal of the second threshold detection module 50 is coupled to the first node, the ground terminal is coupled to the low voltage port, the input terminal is coupled to the gate of the low-side power tube M6, and the output terminal is coupled to the second input terminal of the second control module 60 to output a second judgment signal; The third input terminal of the second control module 60 receives the switch tube control signal, the first output terminal thereof is coupled to the gate of the high-side power tube M5, and the second output terminal thereof is coupled to the gate of the low-side power tube M6; The second control module 60 is configured to: Based on the first judgment signal, the second judgment signal and the switch tube control signal, the on-off of the high-side power tube M5 and the on-off of the low-side power tube M6 are controlled respectively.

[0060] Since the threshold detection circuit provided by the present invention can accurately determine the on / off state of the power tube, the second control module 60 can automatically adjust the dead time of the high-side power tube M5 and the dead time of the low-side power tube M6 based on the judgment signal and the gate control signal to adapt to the deviation caused by factors such as temperature and process. Through this adaptive control, the power tubes are prevented from being turned on at the same time, thereby improving the performance and reliability of the half-bridge circuit and solving many problems caused by the fixed dead time in the prior art.

[0061] If the half-bridge circuit is used in a power circuit such as a class D amplifier, the problem of nonlinear distortion can be effectively reduced because the second control module 60 of the present invention can accurately control the on and off of the power tube.

[0062] As a specific implementation method, please refer to Fig.10 , Fig.10An H-bridge circuit is shown, comprising a symmetrical first half-bridge module and a second half-bridge module, wherein the first half-bridge module and the second half-bridge module both comprise the above-mentioned half-bridge circuit.

[0063] The communication end of the second control module 60 of the first half-bridge module is connected to the communication end of the second control module 60 of the second half-bridge module.

[0064] The second control module 60 of the first half-bridge module is further configured as: The working states of the high-side power tube M5 and the low-side power tube M6 in the second half-bridge module are obtained through the second control module 60, and based on the working states of the high-side power tube M5 and the low-side power tube M6 in the second half-bridge module, the on-off of the high-side power tube M5 and the low-side power tube M6 in the first half-bridge module is controlled; The second control module 60 of the second half-bridge module is further configured as: The working states of the high-side power tube M5 and the low-side power tube M6 in the first half-bridge module are obtained through the first half-bridge module, and based on the working states of the high-side power tube M5 and the low-side power tube M6 in the first half-bridge module, the on and off of the high-side power tube M5 and the low-side power tube M6 in the second half-bridge module are controlled.

[0065] exist Fig.10 In the example of , the half-bridge circuit further includes: a level shift module 70, a high-side driving module 80, a low-side driving module 90 and a bootstrap module 100; The first output end of the second control module 60 is coupled to the gate of the high-side power tube M5 through the high-side driving module 80. The high-side driving module 80 is also coupled to the first node through the bootstrap circuit. The second output end of the second control module 60 is coupled to the gate of the low-side power tube M6 through the low-side driving module 90.

[0066] It can be seen that this structure can determine whether the power tube on the other side is turned on by detecting the working state of the power tube on one side. Specifically, it can be understood that when the gate-source voltage of the power tube on one side drops to a trigger threshold, the corresponding threshold detection module will transmit a feedback signal to the control module on the other side to turn on the power tube on the other side, thereby avoiding the power tubes on both sides from being turned on at the same time, and effectively controlling the dead time within a reasonable range.

[0067] In summary, the embodiment of the present invention can accurately obtain the on-off state of the power tube by utilizing the threshold detection circuit provided by the present invention, thereby realizing automatic adjustment of the dead time to adapt to deviations caused by factors such as temperature and process.

[0068] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A threshold detection circuit, characterized in that: Used to determine whether the power tube is turned off or on, the circuit includes a first PMOS tube, a second NMOS tube, a third PMOS tube, a first resistor, a second resistor, a shaping module and a static current control module; The source of the first PMOS tube is coupled to the high voltage power supply port, and the drain thereof is coupled to the first end of the first resistor, the second end of the first resistor is coupled to the first end of the second resistor, the second end of the second resistor is respectively coupled to the drain of the second NMOS tube and the input end of the first inverter, the output end of the first inverter is coupled to the gate of the third PMOS tube, the source and drain of the third PMOS tube are respectively coupled to the first end and the second end of the first resistor, the drain of the second NMOS tube is coupled to the shaping module, the source of the second NMOS tube is connected to the low voltage port, and the resistance value of the first resistor is greater than the resistance value of the second resistor; The first end of the static current control module and the gate of the second NMOS tube both receive the voltage of the gate of the power tube, and the second end of the static current control module is coupled to the gate of the first PMOS tube; wherein: The static current control module is configured to: control the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube, so as to control the static current of the threshold detection circuit; The shaping module is configured to output a judgment signal based on the voltage of the drain of the second NMOS tube, wherein the judgment signal includes on-off state information of the power tube.

2. The threshold detection circuit according to claim 1, characterized in that: The method of controlling the first PMOS tube to be turned on or off based on the voltage of the gate of the power tube to control the static current of the threshold detection circuit includes: When the voltage of the gate of the power tube rises and the voltage of the gate of the power tube is greater than a first set voltage, the first PMOS tube is controlled to be cut off, so as to control the static current of the threshold detection circuit to be 0; When the voltage of the gate of the power tube decreases and the voltage of the gate of the power tube is less than a second set voltage, the first PMOS tube is controlled to be turned on.

3. The threshold detection circuit according to claim 2, characterized in that: The first set voltage is greater than the first flip voltage, and the first flip voltage is the voltage of the power tube gate corresponding to when the judgment signal is in a downward level flip. The second set voltage is greater than the second flip voltage, and the second flip voltage is the voltage of the power tube gate corresponding to when the judgment signal is in an upward level flip.

4. The threshold detection circuit according to claim 3, characterized in that: The static current control module includes a first inverting Schmitt trigger and a second inverter; The input end of the first inverting Schmitt trigger receives the voltage of the gate of the power tube, and the output end thereof is coupled to the gate of the first PMOS tube through the second inverter; The upward threshold voltage of the first inverting Schmitt trigger is the first set voltage, and the downward threshold voltage is the second set voltage.

5. The threshold detection circuit according to claim 3, characterized in that: The static current control module includes a second Schmitt trigger; The input end of the second Schmitt trigger receives the voltage of the gate of the power tube, and the output end thereof is coupled to the gate of the first PMOS tube; The upward threshold voltage of the second Schmitt trigger is the first set voltage, and the downward threshold voltage is the second set voltage.

6. The threshold detection circuit according to claim 3, characterized in that: The static current control module includes a first buffer, a filter resistor and a filter capacitor; The input end of the first buffer receives the voltage of the gate of the power tube, and the output end thereof is coupled to the first end of the filter resistor. The second end of the filter resistor is respectively coupled to the gate of the first PMOS tube and the first end of the filter capacitor, and the second end of the filter capacitor is grounded.

7. The threshold detection circuit according to claim 1, characterized in that: The shaping module includes a second buffer; The first end of the second buffer is coupled to the drain of the second NMOS tube, and the second end of the second buffer is used to output the determination signal.

8. The threshold detection circuit according to claim 1, characterized in that: The shaping module includes a third Schmitt trigger; A first end of the third Schmitt trigger is coupled to the drain of the second NMOS tube, and a second end of the third Schmitt trigger is used to output the determination signal.

9. The threshold detection circuit according to claim 1, characterized in that: A resistance ratio of the first resistor to the second resistor is greater than or equal to 10.

10. A power circuit, characterized in that: It comprises a power tube, a first control module, and a threshold detection circuit as claimed in any one of claims 1 to 9; The first end of the control module is coupled to the gate of the power tube, the second end thereof is coupled to the output end of the threshold detection circuit, and the third end thereof receives a gate control signal; The input end of the threshold detection circuit is coupled to the gate of the power tube; The first control module is configured to control the on and off of the power tube based on the judgment signal and the gate control signal.

11. A half-bridge circuit, characterized in that: It includes a high-side power tube, a low-side power tube, a first threshold detection module, a second threshold detection module and a second control module, wherein the first threshold detection module and the second threshold detection module both include the threshold detection circuit according to any one of claims 1 to 9; The first end of the high-side power tube is coupled to the high-voltage power supply port, the second end thereof is coupled to the first end of the low-side power tube via a first node, and the second end of the low-side power tube is coupled to the low-voltage port; The power supply end of the first threshold detection module is coupled to the high voltage power supply port, the ground end is coupled to the first node, the input end is coupled to the gate of the high-side power tube, and the output end is coupled to the first input end of the second control module to output a first judgment signal; The power supply end of the second threshold detection module is coupled to the first node, the ground end is coupled to the low voltage port, the input end is coupled to the gate of the low-side power tube, and the output end is coupled to the second input end of the second control module to output a second judgment signal; The third input terminal of the second control module receives the switch tube control signal, the first output terminal thereof is coupled to the gate of the high-side power tube, and the second output terminal thereof is coupled to the gate of the low-side power tube; The second control module is configured as follows: Based on the first judgment signal, the second judgment signal and the switch tube control signal, the on and off of the high-side power tube and the on and off of the low-side power tube are controlled respectively.

Images