N-channel MOSFET (metal-oxide-semiconductor field effect transistor) driving circuit

Abstract

The utility model provides an N-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) driving circuit, which comprises a high-side driving circuit, a low-side driving circuit, a logic control circuit and a diode, the input end of the logic control circuit is connected with an outer pin IN of the N-channel MOSFET drive circuit, a power supply of the logic control circuit is connected with an outer pin VDD of the N-channel MOSFET drive circuit, the ground of the logic control circuit is connected with an outer pin GND of the N-channel MOSFET drive circuit, the output end HI of the logic control circuit is connected with the logic input end of the high-side drive circuit, and the output end HI of the logic control circuit is connected with the logic input end of the high-side drive circuit. And the output end LI of the logic control circuit is connected with the logic input end of the low-side driving circuit. According to the utility model, the logic control circuit is adopted to generate two logic signals HI and LI for dead zone control to respectively control the high-side driving circuit and the low-side driving circuit, so that the problem that only one input logic control is provided in the application of a power supply modulator system is solved, the common-state conduction of a high-side MOS (Metal Oxide Semiconductor) tube and a low-side MOS tube is avoided, and the application of the system is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, in particular to an N-channel MOSFET driving circuit. Background Art

[0002] Power MOSFETs are often used as switches in radio frequency transceiver systems to control the on and off of the power supply of radio frequency power amplifiers. Since the mobility of electrons is 2-3 times that of holes, the greater the mobility, the smaller the resistivity, the lower the power consumption when passing the same current, and the greater the current-carrying capacity. Therefore, in high-power applications, N-channel MOSFETs are usually used as switches.

[0003] The driving of N-channel MOSFETs is usually realized by half-bridge driving. The common half-bridge driving circuit structure in the prior art is as Figure 1 shown, including a high-side driving circuit, a low-side driving circuit, a bootstrap diode D, a capacitor C BS , a high-side MOS transistor M1 and a low-side MOS transistor M2. The half-bridge driving circuit adopts a single-power-supply mode. The low-side driving circuit and the low-voltage area circuit in the high-side driving circuit are powered by the low-side power supply VDD. VDD supplies power to the high-voltage area circuit in the high-side driving circuit through the diode D and the capacitor C BS . The high-voltage area power supply HB and the high-side ground HS in the high-side driving circuit are floating voltages. When the output signal of the high-side driving circuit is logic "1" and the output voltage of the low-side driving circuit is logic "0", the high-side MOS transistor M1 conducts, and the low-side MOS transistor M2 cuts off. The HS voltage rises, and the HB voltage also rises accordingly. Conversely, the HS and HB voltages drop.

[0004] Traditional half-bridge driving requires two external logic control signals HI and LI, and a certain dead time needs to be set for these two signals. Otherwise, it is easy to occur that both the output HO of the high-side driving circuit and the output LO of the low-side driving are logic "1", causing the high-side MOS transistor M1 and the low-side MOS transistor M2 to conduct simultaneously, resulting in the burning of the MOS transistor or the driving circuit. In the application of a power modulator, the system often provides only one logic control signal, which requires adding additional devices, leading to an increase in cost and system size. Summary of the Utility Model

[0005] In view of the technical defects existing in the prior art, the utility model provides an N-channel MOSFET driving circuit that can effectively control the conduction and cut-off of the high-side MOS transistor and the low-side MOS transistor.

[0006] The technical solution adopted by the utility model to solve the above technical problems is as follows:

[0007] An N-channel MOSFET driving circuit, which includes a high-side driving circuit, a low-side driving circuit, a logic control circuit and a diode;

[0008] The input end of the logic control circuit is connected to the external pin IN of the N-channel MOSFET drive circuit, the power supply of the logic control circuit is connected to the external pin VDD of the N-channel MOSFET drive circuit, the ground of the logic control circuit is connected to the external pin GND of the N-channel MOSFET drive circuit, the output end HI of the logic control circuit is connected to the logic input end of the high-side drive circuit, and the output end LI of the logic control circuit is connected to the logic input end of the low-side drive circuit.

[0009] Further, the input end of the low-side drive circuit is connected to the output end LI of the logic control circuit, the power supply of the low-side drive circuit is connected to the external pin VDD of the N-channel MOSFET drive circuit, the ground of the low-side drive circuit is connected to the external pin GND of the N-channel MOSFET drive circuit, and the output end LO of the low-side drive circuit is connected to the external pin LO of the N-channel MOSFET drive circuit.

[0010] Further, the input end of the high-side drive circuit is connected to the output end HI of the logic control circuit, the power supply of the high-side drive circuit is connected to the external pin HB of the N-channel MOSFET drive circuit, the ground of the high-side drive circuit is connected to the external pin HS of the N-channel MOSFET drive circuit, and the output end of the high-side drive circuit is connected to the external pin HO of the N-channel MOSFET drive circuit.

[0011] Further, the anode of the diode is connected to the external pin VDD of the N-channel MOSFET drive circuit, and the cathode of the diode is connected to the external pin HB of the N-channel MOSFET drive circuit.

[0012] Compared with the prior art, the beneficial effects of the present application are as follows:

[0013] In the N-channel MOSFET drive circuit of the present application, two logic signals HI and LI for dead-time control are generated by the logic control circuit to respectively control the high-side drive circuit and the low-side drive circuit, realizing the problem of only providing one input logic control in the power modulator system application, avoiding the common conduction of the high-side MOS transistor and the low-side MOS transistor, and simplifying the system application; at the same time, a high-voltage diode is also integrated inside the circuit, further reducing the device cost and product size of the system, and being more conducive to realizing the miniaturized design of the system.

[0014] In addition, inside the circuit, in addition to integrating the high-side drive circuit and the low-side drive circuit, a logic control circuit is also integrated, which can generate a high-side drive control signal HI and a low-side drive control signal LI with dead-time control through the logic control circuit when a logic control signal is provided externally. HI and LI respectively pass through the high-side drive circuit and the low-side drive circuit, thereby controlling the conduction and cut-off of the high-side MOS transistor and the low-side MOS transistor. In addition, a bootstrap diode is integrated in this circuit, eliminating the need for additional external components. By integrating the logic control circuit and the diode, the system application is greatly simplified and the system cost is reduced. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of an application circuit of a traditional half-bridge gate drive chip;

[0016] Figure 2 is Figure 1 A schematic diagram of the input-output relationship in the circuit;

[0017] Figure 3 It is a schematic diagram of an N-channel MOSFET drive circuit proposed in this application;

[0018] Figure 4 It is an example diagram of an N-channel MOSFET drive circuit proposed in this application;

[0019] Figure 5 It is a schematic diagram of the input-output relationship of the N-channel MOSFET drive circuit proposed in this application. Detailed Description of the Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be further described in detail below with reference to the accompanying drawings.

[0021] As Figure 2-5 shown, an N-channel MOSFET drive circuit of this application includes: a high-side drive circuit, a low-side drive circuit, a logic control circuit, and a diode; the input end of the logic control circuit of the N-channel MOSFET drive circuit is connected to the external pin IN of the drive circuit, the power supply of the logic control circuit is connected to the external pin VDD of the drive circuit, the ground of the logic control circuit is connected to the external pin GND of the drive circuit, the output end HI of the logic control circuit is connected to the logic input end of the high-side drive circuit, and the output end LI of the logic control circuit is connected to the logic input end of the low-side drive circuit.

[0022] The input end of the low-side drive circuit of the N-channel MOSFET drive circuit is connected to the output end LI of the logic control circuit, the power supply of the low-side drive circuit is connected to the external pin VDD of the drive circuit, the ground of the low-side drive circuit is connected to the external pin GND of the drive circuit, and the output end LO of the low-side drive circuit is connected to the external pin LO of the drive circuit.

[0023] The input terminal of the high-side driving circuit of the N-channel MOSFET driving circuit is connected to the output terminal HI of the logic control circuit, the power supply of the high-side driving circuit is connected to the external pin HB of the driving circuit, the ground of the high-side driving circuit is connected to the external pin HS of the driving circuit, and the output terminal HO of the high-side driving circuit is connected to the external pin HO of the driving circuit.

[0024] The anode of the diode of the N-channel MOSFET driving circuit is connected to the external pin VDD of the driving circuit, and the cathode of the diode is connected to the external pin HB of the driving circuit.

[0025] Figure 4 The working principle of the shown N-channel MOSFET driving circuit is as follows: After VDD is powered on, the bootstrap capacitor CB is charged through the diode D to about the VDD voltage; when the external logic input IN is logic "0", the output terminal HI of the internal logic control circuit is logic "0", the output HO of the high-side driving circuit is logic "0", and the external high-side MOS transistor M1 is turned off; LI is logic "1", the output LO of the low-side driving circuit is logic "1", the ground HS of the high-side driving circuit is 0, the power supply HB of the high-side driving circuit is about VDD, and the external low-side MOS transistor M2 is turned on. At this time, the external power modulation output OUT is 0V. When the external logic input IN changes from logic "0" to logic "1", the output terminal LI of the internal logic control circuit becomes logic "0", the output LO of the low-side driving circuit becomes logic "0", and the external low-side MOS transistor M2 is turned off; then the output terminal HI of the logic control circuit becomes logic "1", the output HO of the high-side driving circuit becomes logic "1", the external high-side MOS transistor M1 is turned on. At this time, the external power modulation output OUT is about the bus voltage HV, the ground HS of the high-side driving circuit will become the bus voltage HV, and the power supply HB of the high-side driving circuit becomes VDD + HV. When the external logic input IN changes from logic "1" to logic "0", the output terminal HI of the internal logic control circuit becomes logic "0", the output HO of the high-side driving circuit becomes logic "0", and the external high-side MOS transistor M1 is turned off; then the output terminal LI of the logic control circuit becomes logic "1", the output LO of the low-side driving circuit becomes logic "1", and the external low-side MOS transistor M2 is turned on. At this time, the external power modulation output OUT is 0V.

[0026] The above embodiments are only the preferred embodiments of the present application and cannot be construed as limiting the present invention. For those of ordinary skill in the art in the technical field, without departing from the concept of the present application, several modifications or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present application.

Claims

1. An N-channel MOSFET driving circuit, characterized in that: It includes a high-side drive circuit, a low-side drive circuit, a logic control circuit and a diode; The input end of the logic control circuit is connected to the external pin IN of the N-channel MOSFET drive circuit, the power supply of the logic control circuit is connected to the external pin VDD of the N-channel MOSFET drive circuit, the ground of the logic control circuit is connected to the external pin GND of the N-channel MOSFET drive circuit, the output end HI of the logic control circuit is connected to the logic input end of the high-side drive circuit, and the output end LI of the logic control circuit is connected to the logic input end of the low-side drive circuit.

2. The N-channel MOSFET driving circuit according to claim 1, wherein: The input end of the low-side drive circuit is connected to the output end LI of the logic control circuit, the power supply of the low-side drive circuit is connected to the external pin VDD of the N-channel MOSFET drive circuit, the ground of the low-side drive circuit is connected to the external pin GND of the N-channel MOSFET drive circuit, and the output end LO of the low-side drive circuit is connected to the external pin LO of the N-channel MOSFET drive circuit.

3. The N-channel MOSFET driving circuit according to claim 1, wherein: The input end of the high-side drive circuit is connected to the output end HI of the logic control circuit, the power supply of the high-side drive circuit is connected to the external pin HB of the N-channel MOSFET drive circuit, the ground of the high-side drive circuit is connected to the external pin HS of the N-channel MOSFET drive circuit, and the output end of the high-side drive circuit is connected to the external pin HO of the N-channel MOSFET drive circuit.

4. The N-channel MOSFET driving circuit according to claim 1, characterized in that: The anode of the diode is connected to the external pin VDD of the N-channel MOSFET drive circuit, and the cathode of the diode is connected to the external pin HB of the N-channel MOSFET drive circuit.

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