NMOS (N-channel metal oxide semiconductor) tube high-voltage drain modulation circuit

Abstract

The utility model relates to the technical field of circuit design, in particular to an NMOS (N-channel Metal Oxide Semiconductor) tube high-voltage drain modulation circuit, which comprises an MOS tube driving module, a high-pass filtering module, a high-side driving module, a low-side driving module and a decoupling module, and is characterized in that the input end of the MOS tube driving module is respectively connected with the high-pass filtering module and a TTL (Transistor-Transistor Logic) signal input end; the input end of the high-pass filtering module is connected with a + 5V voltage end, the output end of the MOS tube driving module is respectively connected with the high-side driving module and the low-side driving module, the decoupling module is respectively connected with the MOS tube driving module and a + 70V voltage end, the efficient MOS tube driving module is adopted in the scheme, so that an NMOS tube can be quickly turned on, the requirement of high-frequency modulation is met, and the high-frequency modulation efficiency is improved. The driving circuit can provide enough driving current and voltage to ensure that the MOS tube is quickly switched between a working state and a non-working state.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit design, in particular to an NMOS tube high-voltage drain modulation circuit. Background Art

[0002] In the field of RF power amplifiers, modulation technology is one of the key methods to achieve switch control of power amplifier devices. Common modulation methods are gate modulation and drain modulation. Gate modulation changes the pinch-off and conduction of the power amplifier drain-source current by modulating the gate voltage Vg, thereby achieving switching modulation of the power amplifier working state. Since the gate current is small, the drive circuit design is relatively simple, and good rising and falling edge characteristics can be obtained. However, when the drain-source current is pinched off, the gate voltage is low, and the power amplifier working state is prone to enter the breakdown region, causing the power amplifier device to burn out, so the stability of gate modulation is poor.

[0003] Compared with gate modulation, drain modulation changes the voltage state of the power amplifier (such as 0V and normal working voltage Vd) by designing the power switch circuit to achieve switching modulation between the working state and non-working state of the power amplifier. The reliability and stability of drain modulation are higher, but the modulation circuit needs to be reasonably designed to meet the rising and falling edge requirements of the power amplifier.

[0004] At present, most traditional power amplifier devices use low-voltage devices such as gallium arsenide (GaAs), and the corresponding low-voltage modulation circuit design is relatively easy to implement. However, with the development of semiconductor technology, silicon carbide (CaN) tube cores are gradually being widely used in power amplifier devices. The drain operating voltage of CaN tube cores is much higher than that of GaAs, generally above 48V. In the process of high-voltage drain modulation, due to the high voltage, it is easy to cause component damage. Utility Model Content

[0005] The utility model aims to solve the problem of component damage in the high-voltage drain modulation process within 100V and proposes an NMOS tube high-voltage drain modulation circuit.

[0006] The utility model is realized by the following technical solutions:

[0007] An NMOS tube high-voltage drain modulation circuit comprises a MOS tube driving module, a high-pass filter module, a high-side driving module, a low-side driving module and a decoupling module, wherein the input end of the MOS tube driving module is respectively connected to the high-pass filter module and a TTL signal input end, the input end of the high-pass filter module is connected to a +5V voltage end, the output end of the MOS tube driving module is respectively connected to the high-side driving module and the low-side driving module, and the decoupling module is respectively connected to the MOS tube driving module and a +70V voltage end.

[0008] Furthermore, the MOS tube driving module includes a MOS tube driver U3, and the model of the MOS tube driver U3 is LTC444EMS8E#PBF.

[0009] Furthermore, the high-pass filter module includes a resistor R5 and a capacitor C7, and pin 1 of the MOS tube driver U3 is respectively connected to the TTL signal input end and one end of the resistor R5, and the other end of the resistor R5 is respectively connected to one end of the capacitor C7, pin 5 of the MOS tube driver U3, pin 9 of the MOS tube driver U3, and a low-side drive module, and the other end of the capacitor C7 is respectively connected to the +5V voltage end and one end of the resistor R3, and the other end of the resistor R3 is connected to pin 2 of the MOS tube driver U3.

[0010] Furthermore, the high-side driving module includes a resistor R2 and a MOS tube U1, pin 7 of the MOS tube driver U3 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the gate of the MOS tube U1, and the source of the MOS tube U1 is connected to the decoupling module.

[0011] Furthermore, the low-side driving module includes a resistor R4 and a MOS tube U4, the 4th pin of the MOS tube driver U3 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the gate of the MOS tube U4, and the source of the MOS tube U4 is connected to the other end of the resistor R5.

[0012] Furthermore, the decoupling module includes capacitors C1, C2 and C3. The source of the MOS tube U1 is respectively connected to one end of capacitor C1, one end of capacitor C2, one end of capacitor C3 and a +70V voltage end. The other ends of capacitor C1, C2 and C3 are all connected to one end of capacitor C5 and then grounded. The other end of capacitor C5 is connected to pin 3 of the MOS tube driver U3.

[0013] Beneficial effects of the utility model:

[0014] (1) The utility model proposes an NMOS tube high-voltage drain modulation circuit with a simple design structure and a small number of components, which reduces the circuit complexity. Through the reasonable configuration of the high-pass filter module and the decoupling module, the stability of the circuit is enhanced to ensure stable operation under high-voltage working conditions;

[0015] (2) The utility model proposes an NMOS tube high-voltage drain modulation circuit, which adopts an efficient MOS tube driving module, so that the NMOS tube can be turned on quickly to meet the needs of high-frequency modulation. The driving circuit can provide sufficient driving current and voltage to ensure that the MOS tube can switch quickly between the working state and the non-working state;

[0016] (3) The utility model proposes an NMOS tube high-voltage drain modulation circuit. By reasonably designing the configuration of the high-pass filter module and the drive module, the circuit can provide faster rising and falling edge characteristics, reduce the switching time, and improve the switching efficiency and response speed of the circuit;

[0017] (4) The utility model proposes an NMOS tube high-voltage drain modulation circuit, which can provide sufficient driving capability through the MOS tube driving module and is suitable for NMOS tubes with gate-source parasitic capacitance as high as 5000pF, ensuring that the NMOS tube can be reliably turned on and off under high-voltage working conditions;

[0018] (5) The utility model proposes an NMOS tube high-voltage drain modulation circuit, which has a strong adaptability to high and low temperatures through the configuration of a decoupling module, thereby greatly protecting the electronic components in the circuit and extending the service life of the circuit.

[0019] In summary, the NMOS tube high-voltage drain modulation circuit proposed in this scheme realizes high efficiency, stability and reliability of high-voltage drain modulation through reasonable circuit design, and provides a high-quality solution for the application of high-voltage power amplifier devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments 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 labor.

[0021] Figure 1 The utility model discloses a circuit principle diagram of an NMOS tube high voltage drain modulation circuit. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the utility model more clearly understood, the utility model is further described in detail below in conjunction with embodiments and drawings. The schematic implementation manner of the utility model and its description are only used to explain the utility model and are not intended to limit the utility model.

[0023] Example 1

[0024] An NMOS tube high voltage drain modulation circuit includes the following modules:

[0025] MOS tube driver module, mainly responsible for driving high-side and low-side MOS tubes;

[0026] High-pass filter module, used to filter out power supply noise and ensure signal purity;

[0027] The high-side driving module controls the on and off of the high-voltage side MOS tube;

[0028] The low-side driving module controls the conduction and cutoff of the low-voltage side MOS tube;

[0029] Decoupling module, used to stabilize power supply and reduce voltage fluctuations.

[0030] In the high-voltage drain modulation process, the main issue is the stability and reliability of components under high-voltage conditions, especially avoiding damage to components due to overvoltage or overcurrent.

[0031] This embodiment solves the problem of component damage in high voltage drain modulation within 100V through the following design:

[0032] Voltage stabilization and filtering: Through the design of high-pass filter module and decoupling module, the voltage fluctuation in the circuit is ensured to be minimal, providing a stable operating voltage and reducing the damage to components caused by voltage fluctuation.

[0033] Bootstrap circuit: The MOS tube driver adopts a bootstrap circuit to generate a gate drive voltage higher than the power supply voltage, ensuring the stability of the high-side MOS tube under high voltage conditions and avoiding component damage caused by insufficient gate drive under high voltage.

[0034] Transient current driving capability: The preferred MOS driver provides sufficient transient current driving capability to ensure that the MOS tube is quickly turned on and off, reducing component damage caused by transitional voltage and current during the turn-on and turn-off process.

[0035] High-side and low-side separation design: Through the separation design of high-side drive and low-side drive, the circuit can control the MOS tubes on the high-voltage and low-voltage sides respectively under different working conditions, ensuring the reliability of the power amplifier in high-voltage drain modulation.

[0036] refer to Figure 1The present embodiment proposes an NMOS tube high-voltage drain modulation circuit, which specifically includes a MOS tube driver U3. The model of the MOS tube driver U3 is LTC444EMS8E#PBF. Pin 1 of the MOS tube driver U3 is respectively connected to a TTL pulse input terminal and one end of a resistor R5. The other end of the resistor R5 is respectively connected to one end of a capacitor C7, pin 5 of the MOS tube driver U3, pin 9 of the MOS tube driver U3, and a source of the MOS tube U4. The other end of the capacitor C7 is respectively connected to a +5V voltage input terminal and one end of the resistor R3. The other end of the resistor R3 is connected to pin 2 of the MOS tube driver U3. Pin 3 of the MOS tube driver U3 is respectively connected to one end of the capacitor C5. The anode of the switching diode D1, V CC voltage input end, the cathode of the switching diode D1 is respectively connected to one end of the capacitor C4 and the 6th pin of the MOS tube driver U3, the other end of the capacitor C4 is respectively connected to the 8th pin of the MOS tube driver U3, the drain of the MOS tube U4, and the drain of the MOS tube U1, the source of the MOS tube U1 is respectively connected to one end of the capacitor C3, one end of the capacitor C2, one end of the capacitor C1, and the +70V voltage end, the other end of the capacitor C3, the other end of the capacitor C2, and the other end of the capacitor C1 are all connected to the other end of the capacitor C5, the gate of the MOS tube U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the 7th pin of the MOS tube driver U3, the gate of the MOS tube U4 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the 4th pin of the MOS tube driver U3.

[0037] In the NMOS tube high-voltage drain modulation circuit, the NMOS tube is used as a switching device, and its on and off states are controlled by adjusting its gate voltage, thereby realizing the switching between the working and non-working states of the power amplifier tube.

[0038] When the gate voltage of the NMOS tube exceeds a certain value of the source voltage (usually between 10 and 15V), the source and drain of the NMOS tube are turned on, and the power amplifier tube enters the working state. When the gate voltage is equal to or lower than the source voltage, the source and drain of the NMOS tube are cut off, and the power amplifier tube enters the non-working state.

[0039] However, since the voltage provided by the system to the drain of the power amplifier is usually the highest voltage of the system, in order to ensure the normal operation of the NMOS tube, a special boost circuit is required to provide sufficient gate drive voltage, which increases the complexity and cost of circuit design.

[0040] This embodiment uses a highly integrated MOS tube driver to modulate the NMOS tube. The MOS tube driver with a voltage bootstrap function is used. The driver can automatically boost the voltage to provide the required gate drive voltage without the need to design a special boost circuit.

[0041] The voltage bootstrap function of the MOS tube driver can provide sufficient gate drive voltage, so that the gate voltage of the NMOS tube is 10~15V higher than the source voltage when the NMOS tube is turned on, thereby ensuring the reliable conduction of the NMOS tube. The highly integrated MOS tube driver ensures the normal operation of the NMOS tube in a high-voltage environment, reducing the risk of component damage.

[0042] Example 2

[0043] This embodiment proposes a functional principle of an NMOS tube high-voltage drain modulation circuit based on the embodiment 1.

[0044] In this embodiment, a MOS tube driver of model LTC444EMS8E#PBF is preferably used. The MOS tube driver is the key to the design of the drain modulation circuit, and its performance directly affects the rising and falling edges of the modulated output signal. The MOS tube in the circuit of this design adopts a voltage control method and theoretically does not need current drive, but the gate of the MOS tube is a capacitive input, that is, there is a parasitic capacitance between the gate source GS and the gate drain GD. When the pulse signal is modulated, it is equivalent to the MOS tube driver charging and discharging the capacitance of the MOS tube gate; when charging, the driver needs to provide a certain amount of charge, and the gate is equivalent to a momentary short circuit. When discharging, the MOS tube driver needs to absorb the charge released by the gate in a short time, so a certain transient current driving capability is required. The larger the driving current provided, the faster the MOS tube is turned on.

[0045] refer to Figure 1 , VCC is the power input of the preferred MOS tube driver. The MOS tube driver pin 2 is usually added with +5V, and the 4th pin is bootstrapped to output high voltage to the gate of the MOS tube U4. The source of the MOS tube U4 is connected to the drain source of the power amplifier. If the drain source has VDD of 70V, the gate voltage of the MOS tube U4 is greater than the source voltage. The source and drain of the MOS tube U4 are turned on, and 70V is discharged to the ground;

[0046] In this embodiment, the preferred MOS tube driver can, when the TTL pulse modulation input of pin 1 is high, pin 2 is often added with +5V and the output of pin 4 will not be processed, but pin 7 is processed first to bootstrap the output high voltage. The gate voltage of MOS tube U1 is greater than the 70V voltage often added to the source of MOS tube U1, the source and drain of MOS tube U1 are turned on, and 70V enters the drain of the power amplifier to put the power amplifier into operation.

[0047] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and the description only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. An NMOS tube high voltage drain modulation circuit, characterized in that: It includes a MOS tube driving module, a high-pass filter module, a high-side driving module, a low-side driving module, and a decoupling module. The input end of the MOS tube driving module is respectively connected to the high-pass filter module and the TTL signal input end, the input end of the high-pass filter module is connected to the +5V voltage end, the output end of the MOS tube driving module is respectively connected to the high-side driving module and the low-side driving module, and the decoupling module is respectively connected to the MOS tube driving module and the +70V voltage end.

2. The NMOS tube high voltage drain modulation circuit according to claim 1, characterized in that: The MOS tube driving module includes a MOS tube driver U3, and the model of the MOS tube driver U3 is LTC444EMS8E#PBF.

3. The NMOS tube high voltage drain modulation circuit according to claim 2, characterized in that: The high-pass filter module includes a resistor R5 and a capacitor C7. Pin 1 of the MOS tube driver U3 is respectively connected to the TTL signal input end and one end of the resistor R5. The other end of the resistor R5 is respectively connected to one end of the capacitor C7, the 5th pin of the MOS tube driver U3, the 9th pin of the MOS tube driver U3, and the low-side drive module. The other end of the capacitor C7 is respectively connected to the +5V voltage end and one end of the resistor R3. The other end of the resistor R3 is connected to pin 2 of the MOS tube driver U3.

4. The NMOS tube high voltage drain modulation circuit according to claim 3, characterized in that: The high-side driving module includes a resistor R2 and a MOS tube U1. Pin 7 of the MOS tube driver U3 is connected to one end of the resistor R2. The other end of the resistor R2 is connected to the gate of the MOS tube U1. The source of the MOS tube U1 is connected to the decoupling module.

5. The NMOS tube high voltage drain modulation circuit according to claim 3, characterized in that: The low-side driving module includes a resistor R4 and a MOS tube U4. Pin 4 of the MOS tube driver U3 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the gate of the MOS tube U4, and the source of the MOS tube U4 is connected to the other end of the resistor R5.

6. The NMOS tube high voltage drain modulation circuit according to claim 4, characterized in that: The decoupling module includes capacitors C1, C2 and C3. The source of the MOS tube U1 is respectively connected to one end of the capacitor C1, one end of the capacitor C2, one end of the capacitor C3 and the +70V voltage end. The other ends of the capacitors C1, C2 and C3 are all connected to one end of the capacitor C5 and then grounded. The other end of the capacitor C5 is connected to pin 3 of the MOS tube driver U3.

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