MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) driving circuit with charge discharge function

Abstract

The utility model relates to the technical field of driving circuits, in particular to an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) driving circuit with a charge discharge function, which comprises a control logic circuit, an MOSFET driving unit and a charge discharge circuit. According to the utility model, the control logic circuit and the MOSFET driving unit are integrated inside the circuit, and the charge discharge circuit is also integrated inside the circuit, so that the charge of the drain electrode of the power MOSFET can be rapidly discharged through the charge discharge circuit on the chip after the P-channel MOSFET is turned off while the external P-channel power MOSFET is controlled and driven by TTL logic signals, and the power supply efficiency is improved. Therefore, the current trailing phenomenon after the radio frequency power amplifier is turned off is avoided, and the reliability of the system is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a MOSFET drive circuit especially to a MOSFET drive circuit with charge discharge function belongs to drive circuit technical field. BACKGROUND

[0002] In some applications, the system requires higher and higher transmitting power of the radio frequency transmitter, so that GaN radio frequency power amplifier is widely used, in order to control the power on-off state of GaN radio frequency power amplifier, MOSFET drive circuit is commonly used to drive P channel power MOSFET to realize.

[0003] The common P channel power MOSFET as the switching power modulation application circuit structure is as shown in Figure 4 It contains a MOSFET drive circuit and a P channel power MOSFET, the circuit adopts single power supply mode, the power supply end of MOSFET drive circuit and the source of P channel MOSFET are connected to external power VDD;The output end VO of MOSFET drive circuit is connected with the gate of P channel MOSFET;The drain of P channel MOSFET is connected to the power supply end of GaN power amplifier;The input end of MOSFET drive circuit is connected to external logic control end IN, when the logic control end IN inputs low level, the output end VO of drive circuit outputs high level VDD, and P channel MOSFET is turned off, so that the drain output VOUT of P channel MOSFET is 0, at this time, GaN power amplifier is powered off and does not work, when the logic control end IN inputs high level, the output end VO of drive circuit outputs a low level, and the voltage is about VDD-10V, P channel MOSFET is turned on, so that the drain output VOUT of P channel MOSFET is about power voltage VDD, at this time, GaN power amplifier works normally, the input-output relationship diagram of P channel power MOSFET drive circuit without charge discharge circuit is as shown in Figure 2 .

[0004] In order to reduce AC coupling, the power supply end of GaN power amplifier is generally placed with decoupling capacitor C1, and the capacitor and the capacitor Cgd between the gate and the drain of P channel MOSFET store a certain amount of charge when MOSFET is turned on, because the impedance between the power supply end of GaN power amplifier and the ground is often relatively large, when P channel MOSFET is switched from on to off, the charge on the capacitor of MOSFET drain VOUT cannot be quickly released, and current tail phenomenon occurs, which affects the system performance. INVENTION CONTENTS

[0005] The utility model provides a MOSFET drive circuit with charge leakage function, can realize by TTL logic signal control drive external P channel power MOSFET, and after P channel MOSFET is turned off, through the charge leakage circuit on the chip, the charge of power MOSFET drain is quickly leaked.

[0006] The utility model discloses a technical scheme that solves the above technical problems:

[0007] A MOSFET drive circuit with charge leakage function, comprising a control logic circuit, a MOSFET drive unit, and a charge leakage circuit, the external pin IN of the MOSFET drive circuit is electrically connected to the input end of the control logic circuit, and the external pin VDD of the MOSFET drive circuit is electrically connected to the power supply of the control logic circuit.

[0008] One output end of the control logic circuit is electrically connected to the input end of the MOSFET drive circuit, and the other output end of the control logic circuit is electrically connected to the input end of the charge leakage circuit.

[0009] Further, the output end of the MOSFET drive unit is electrically connected to the external pin VO of the MOSFET drive circuit.

[0010] Further, the output end of the charge leakage circuit is electrically connected to the external pin PD of the MOSFET drive circuit.

[0011] Further, the MOSFET drive unit and the charge leakage circuit are connected in parallel on the control logic circuit, and a MOSFET semiconductor field effect transistor is electrically connected to the external pin VO of the MOSFET drive circuit.

[0012] Further, a power amplifier is electrically connected between the MOSFET semiconductor field effect transistor and the charge leakage circuit.

[0013] Further, the input end of the power amplifier is connected through a capacitor C1.

[0014] Further, the external pin VDD of the MOSFET semiconductor field effect transistor is electrically connected to the external pin VDD of the MOSFET drive circuit.

[0015] Further, the output end of the charge leakage circuit is connected to the external pin PD of the MOSFET drive circuit.

[0016] The utility model at least has the following beneficial effects:

[0017] In addition to the integrated control logic circuit and the driving unit, the circuit also integrates a charge discharge circuit, which can realize the control of the driving of the external P-channel power MOSFET by the TTL logic signal, and can also realize the fast discharge of the charge on the drain of the power MOSFET through the charge discharge circuit on the chip after the P-channel MOSFET is turned off, thereby avoiding the current tailing phenomenon of the radio frequency power amplifier after the power amplifier is turned off, and improving the reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The schematic diagram of the P-channel power MOSFET driving circuit proposed in the application is shown in the figure.

[0019] Figure 2 The input and output relationship of the P-channel power MOSFET driving circuit is shown in the figure. Figure 1

[0020] Figure 3 The schematic diagram of the commonly used P-channel MOSFET power supply modulation application circuit is shown in the figure.

[0021] Figure 4 The input and output relationship of the circuit is shown in the figure. Figure 3

[0022] In the figure, 1 is a control logic circuit, 2 is a MOSFET driving circuit, 3 is a charge discharge circuit, and 4 is a power amplifier. DETAILED DESCRIPTION

[0023] The technical scheme of the application will be further described in detail in combination with the drawings and specific embodiments.

[0024] As Figure 1 ​​As shown, the MOSFET drive circuit with charge leakage function provided by the embodiment comprises a control logic circuit 1, a MOSFET drive unit 2 and a charge leakage circuit 3; an external pin IN of the MOSFET drive circuit is electrically connected with an input end of the control logic circuit 1, and an external pin VDD of the MOSFET drive circuit is electrically connected with a power supply of the control logic circuit 1; one output end of the control logic circuit 1 is electrically connected with an input end of the MOSFET drive unit 2, and another output end of the control logic circuit 1 is electrically connected with an input end of the charge leakage circuit 3; an output end of the MOSFET drive unit 2 is electrically connected with an external pin VO of the MOSFET drive circuit, and an output end of the charge leakage circuit 3 is electrically connected with an external pin PD of the MOSFET drive circuit. In the circuit of the present application, in addition to the normal function of the MOSFET drive unit 2, the charge leakage circuit 3 is also designed. In a typical application, the MOSFET semiconductor field effect transistor is electrically connected with the charge leakage circuit 3, and a power amplifier 4 is electrically connected between the MOSFET semiconductor field effect transistor and the charge leakage circuit 3. The input end of the power amplifier 4 is connected through a capacitor C1. After the P-channel MOSFET semiconductor field effect transistor is turned off, the charge on the drain capacitor of the MOSFET semiconductor field effect transistor is quickly discharged through the discharge end PD of the charge leakage circuit 3, so as to avoid the current tail phenomenon of the radio frequency power amplifier after being turned off, and the reliability of the system is improved.

[0025] Further, as shown in Figure 1 and Figure 2 , the external pin VDD of the MOSFET semiconductor field effect transistor is electrically connected with the external pin VDD of the MOSFET drive circuit, and the output end of the charge leakage circuit 3 is connected with the external pin PD of the MOSFET drive circuit. After the VDD is powered on, when the external logic input IN is logic "0", first, the MOSFET drive circuit outputs high level, and the voltage value is about VDD, so that the P-channel power MOSFET semiconductor field effect transistor is turned off. After a certain delay time, the charge leakage circuit works, a low resistance channel is formed between the PD end and the GND, the voltage of the PD end is pulled to low level, and the charge on the capacitor in the rear stage is quickly discharged to the GND through the port.

[0026] After the VDD is powered on, when the external logic input IN is logic "1", first, the charge leakage circuit 3 is closed, the low resistance channel between the PD end and the GND is turned off, the PD end outputs high resistance state, and after a certain delay time, the MOSFET drive circuit 3 outputs low level, and the voltage value is about VDD-10V, so that the P-channel power MOSFET semiconductor field effect transistor is turned on.

[0027] As shown in Figures 1-4 , the principle of the MOSFET drive circuit with charge leakage function provided by the embodiment is as follows:

[0028] After VDD is powered on, when the external logic input IN is logic "0", first the MOSFET drive circuit outputs high level, voltage value is about VDD, so that the P-channel power MOSFET semiconductor field effect transistor is turned off, after a certain delay time, the charge discharge circuit works, a low resistance channel is formed between the PD end and the GND, and the voltage of the PD end is pulled to low level, and the charge on the rear-stage capacitor is discharged to the GND through the port quickly;

[0029] After VDD is powered on, when the external logic input IN is logic "1", first the charge discharge circuit 3 is closed, and the low resistance channel between the PD end and the GND is turned off, so that the PD end outputs high resistance state, after a certain delay time, the MOSFET drive circuit 3 outputs low level, voltage value is about VDD-10V, so that the P-channel power MOSFET semiconductor field effect transistor is turned on.

[0030] The above description shows and describes the preferred embodiments of the present application, and it should be understood that the present application is not limited to the forms disclosed herein, and the changes and modifications made by those skilled in the art without departing from the spirit and scope of the present application should be within the scope of protection of the claims of the present application.

Claims

1. A MOSFET drive circuit with a charge drain function, characterized by: Including control logic circuit (1), MOSFET drive unit (2) and charge discharge circuit (3), the external pin IN of MOSFET drive circuit is electrically connected with the input end of control logic circuit (1), the external pin VDD of MOSFET drive circuit is electrically connected with the power supply of control logic circuit (1); One output end of control logic circuit (1) is electrically connected with the input end of MOSFET drive unit (2), another output end of control logic circuit (1) is electrically connected with the input end of charge discharge circuit (3).

2. The MOSFET driving circuit with a charge leakage function according to claim 1, characterized in that: The external pin VO of MOSFET drive circuit is electrically connected with the output end of MOSFET drive unit (2).

3. The MOSFET driving circuit with a charge leakage function according to claim 1, characterized in that: The external pin PD of MOSFET drive circuit is connected with the output end of charge discharge circuit (3).

4. The MOSFET driving circuit with a charge leakage function according to claim 1, characterized in that: MOSFET drive unit (2) and charge discharge circuit (3) are arranged in parallel on control logic circuit (1), MOSFET semiconductor field effect transistor is electrically connected with the external pin VO of MOSFET drive circuit.

5. The MOSFET driving circuit with a charge leakage function according to claim 4, characterized in that: MOSFET semiconductor field effect transistor is electrically connected with power amplifier (4) between charge discharge circuit (3).

6. The MOSFET driving circuit with a charge leakage function according to claim 5, characterized in that: The input end of power amplifier (4) is connected through capacitor C1.

7. The MOSFET driving circuit with a charge leakage function according to claim 1, characterized in that: The external pin VDD of MOSFET semiconductor field effect transistor is electrically connected with the external pin VDD of MOSFET drive circuit.

8. The MOSFET driving circuit with a charge leakage function according to claim 1, characterized in that: The output end of charge discharge circuit is connected with the external pin PD of MOSFET drive circuit.

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