A zero-startup power consumption same-phase drive level conversion circuit

Abstract

The present invention provides a same-phase drive level conversion circuit with zero startup power consumption, comprising a silicon carbide field-effect transistor, a two-stage level conversion circuit for controlling level conversion and connected to the silicon carbide field-effect transistor, and a driving current amplifier circuit for driving the silicon carbide field-effect transistor and connected to the two-stage level conversion circuit, wherein the positive electrode of the circuit is connected to the driving current amplifier circuit; the two-stage level conversion circuit comprises a first field-effect transistor and a second field-effect transistor, the drain of the first field-effect transistor is connected to the gate of the second field-effect transistor, the source of the first field-effect transistor and the source of the second field-effect transistor are commonly connected to the negative electrode of the circuit, the drain of the second field-effect transistor is connected to the gate of the silicon carbide field-effect transistor, and the source of the second field-effect transistor is connected to the source of the silicon carbide field-effect transistor; the present invention ensures the level conversion function while achieving zero-power standby energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of driving circuits, and in particular to a same-phase driving level conversion circuit with zero startup power consumption. Background Art

[0002] Silicon carbide has inherent advantages in the field of high-voltage technology. With the development of new energy technologies, the application scenarios of silicon carbide are becoming more and more extensive. The application of high-voltage silicon carbide reduces the technical difficulty of designing high-voltage products. For example, in AC600V applications, after calculating the voltage fluctuation, the rectified voltage reaches 950V. If a stable and reliable auxiliary power supply is designed at this voltage, it is undoubtedly difficult. However, high-voltage silicon carbide devices provide an excellent alternative. The 1700V withstand voltage MOSFET provides a safe design margin for the auxiliary power supply. Combined with an offline controller, a reliable auxiliary power supply can be designed.

[0003] However, the driving voltage of conventional offline controllers is generally 8V~10V, while the driving voltage requirement of silicon carbide is 15~18V, so a level conversion circuit is needed in the middle. Although there are chips that can perform level conversion, the standby power consumption of the chip is generally greater than 300uA, which brings great difficulty to the design of the startup circuit of the offline controller. Summary of the Invention

[0004] The object of the present invention is to provide a same-phase driving level conversion circuit which can ensure the level conversion function and realize zero power consumption in standby mode and zero power consumption in startup mode.

[0005] To solve the above technical problems, the present invention provides a zero-startup power consumption same-phase drive level conversion circuit, comprising a silicon carbide field-effect transistor, a two-stage level inversion circuit for controlling level inversion and connected to the silicon carbide field-effect transistor, and a drive current amplifier circuit for driving the silicon carbide field-effect transistor and connected to the two-stage level inversion circuit, wherein the positive electrode of the circuit is connected to the drive current amplifier circuit; the two-stage level inversion circuit comprises a first field-effect transistor and a second field-effect transistor, the drain of the first field-effect transistor is connected to the gate of the second field-effect transistor, the source of the first field-effect transistor and the source of the second field-effect transistor are commonly connected to the negative electrode of the circuit, and the drain of the second field-effect transistor is connected to the gate of the silicon carbide field-effect transistor, and the source of the second field-effect transistor is connected to the source of the silicon carbide field-effect transistor, so that when the first field-effect transistor is turned off and the second field-effect transistor is turned on, the silicon carbide field-effect transistor is in a cut-off state, and when the first field-effect transistor is turned on and the second field-effect transistor is turned off, the silicon carbide field-effect transistor is in a conducting state.

[0006] Furthermore, the driving current amplification circuit includes a first transistor, the base of the first transistor is connected to the drain of the first field-effect transistor through a fourth resistor, the collector of the first transistor is connected to the gate of the silicon carbide field-effect transistor through a fifth resistor, and a second resistor is arranged between the base and the emitter of the first transistor, so that when the first field-effect transistor is turned on and the second field-effect transistor is turned off, the second resistor and the fourth resistor apply voltage and turn on the first transistor.

[0007] Furthermore, it also includes a fast shutdown circuit, which includes a second transistor, the collector of the second transistor is connected to the base of the first transistor, the emitter of the second transistor is connected to the positive pole of the circuit, and the base of the second transistor is connected to the gate of the first field effect transistor and the offline controller through a third resistor and a capacitor.

[0008] Furthermore, the base and emitter of the second transistor are connected via a first resistor.

[0009] Furthermore, the diode is connected between the third resistor and the capacitor, and the anode of the diode is connected to the positive electrode or the negative electrode of the circuit.

[0010] Furthermore, the third resistor and the capacitor form an RC time constant, and the RC time constant is 200 ns.

[0011] The beneficial effects of the present invention are: the level inversion control is controlled by a two-stage level inversion circuit, and the drive turn-on signal is amplified in cooperation with the drive current amplifier circuit to drive the silicon carbide field effect tube to turn on. At the same time, a fast shutdown circuit is provided to control the fast shutdown of the first transistor in the drive current amplifier circuit to control the shutdown of the silicon carbide field effect tube, and in the standby state of the silicon carbide field effect tube, zero power consumption can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a circuit diagram of the present invention. DETAILED DESCRIPTION

[0013] The following will be combined with the accompanying 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 embodiments described 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 are within the scope of protection of the present invention.

[0014] It should be understood by those skilled in the art that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0015] It is understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0016] like Figure 1 The present invention provides a same-phase drive level conversion circuit with zero startup power consumption, including a silicon carbide field-effect transistor Q5, a two-stage level inversion circuit for controlling level inversion and connected to the silicon carbide field-effect transistor Q5, a driving current amplifying circuit for driving the silicon carbide field-effect transistor Q5 and connected to the two-stage level inversion circuit, and a fast shutdown circuit, wherein the positive electrode VCC of the circuit is connected to the driving current amplifying circuit.

[0017] Among them, the two-stage level inversion circuit includes a first field-effect transistor Q3 and a second field-effect transistor Q4, the drain of the first field-effect transistor Q3 is connected to the gate of the second field-effect transistor Q4, the source of the first field-effect transistor Q3 and the source of the second field-effect transistor Q4 are commonly connected to the circuit negative electrode GND, and the drain of the second field-effect transistor Q4 is connected to the gate of the silicon carbide field-effect transistor Q5, and the source of the second field-effect transistor Q4 is connected to the source of the silicon carbide field-effect transistor Q5, so that when the first field-effect transistor Q3 is turned off and the second field-effect transistor Q4 is turned on, the silicon carbide field-effect transistor Q5 is in the off state, and when the first field-effect transistor Q3 is turned on and the second field-effect transistor Q4 is turned off, the silicon carbide field-effect transistor Q5 is in the on state.

[0018] The driving current amplification circuit includes a first transistor Q1. The base of the first transistor Q1 is connected to the drain of the first field-effect transistor Q3 via a fourth resistor R4. The collector of the first transistor Q1 is connected to the gate of the silicon carbide field-effect transistor Q5 via a fifth resistor R5. A second resistor R2 is provided between the base and the emitter of the first transistor Q1. When the first field-effect transistor Q3 is turned on and the second field-effect transistor Q4 is turned off, a voltage is applied between the second resistor R2 and the fourth resistor R4, thereby turning on the first transistor Q1.

[0019] The fast shutdown circuit includes a second transistor Q2, the collector of the second transistor Q2 is connected to the base of the first transistor Q1, the emitter of the second transistor Q2 is connected to the positive electrode VCC of the circuit, and the base of the second transistor Q2 is connected to the gate of the first field effect transistor Q3 and the offline controller 1 through a third resistor R3 and a capacitor C1.

[0020] The base and emitter of the second transistor Q2 are connected via the first resistor R1; the diode D1 is connected between the third resistor R3 and the capacitor C1, and the anode of the diode D1 is connected to the circuit positive electrode VCC or the circuit negative electrode GND.

[0021] In a preferred embodiment of this solution, the third resistor R3 and the capacitor C1 form an RC time constant, and the RC time constant is 200 ns.

[0022] This solution is used in three steps:

[0023] 1. Standby start: During the standby start period, the offline controller 1 is at a low level, Q3 is off, Q4 is on, and the SiC field effect transistor drive is pulled low. At this time, all devices are in the cut-off state, and there are no power-consuming components, achieving the goal of zero standby energy consumption.

[0024] 2. Drive on: As the starting voltage VCC rises, since the offline controller will not start before reaching the starting voltage of 18V, the offline controller pin6 outputs a low voltage and Q3 is in the off-state. After the VCC voltage rises to 2V, Q4 starts to turn on and the silicon carbide field effect tube Q5 is turned off. After the VCC voltage reaches 18V, the offline driver starts and starts to output the PWM waveform. When the output is high, Q3 starts to turn on and Q4 turns off. At the same time, R4 and R2 apply voltage, Q1 starts to turn on, and the silicon carbide field effect tube is driven by resistor R5. The turn-on level is approximately equal to VCC and is not limited by the PWM drive waveform. The PWM amplitude can be greater than Q3 fully turned on, usually 4.5V.

[0025] 3. Drive shutdown: When the PWM level is low, Q3 is closed, Q4 is turned on, and the silicon carbide field effect tube is turned off. At this time, the RC time constant composed of C1 and R3 (usually the RC time constant is designed to be 200ns) turns on Q2, and Q2 controls Q1 to turn off quickly, reducing the driving power consumption. When the PWM waveform is turned on next time, C1 is quickly discharged through diode D1, usually 50ns to complete the discharge, preparing for the next shutdown to provide suitable time for Q2 to turn on.

[0026] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A zero-startup power consumption same-phase drive level conversion circuit, characterized by: The invention comprises a silicon carbide field effect transistor Q5, a two-stage level inversion circuit for controlling level inversion and connected to the silicon carbide field effect transistor Q5, and a driving current amplifier circuit for driving the silicon carbide field effect transistor Q5 and connected to the two-stage level inversion circuit, wherein the positive electrode VCC of the circuit is connected to the driving current amplifier circuit; the two-stage level inversion circuit comprises a first field effect transistor Q3 and a second field effect transistor Q4, wherein the drain of the first field effect transistor Q3 is connected to the gate of the second field effect transistor Q4, and the first field effect transistor Q3 is connected to the gate of the second field effect transistor Q4. The source of Q3 and the source of the second field effect transistor Q4 are commonly connected to the negative electrode GND of the circuit, and the drain of the second field effect transistor Q4 is connected to the gate of the silicon carbide field effect transistor Q5. The source of the second field effect transistor Q4 is connected to the source of the silicon carbide field effect transistor Q5, so that when the first field effect transistor Q3 is turned off and the second field effect transistor Q4 is turned on, the silicon carbide field effect transistor Q5 is in the off state. When the first field effect transistor Q3 is turned on and the second field effect transistor Q4 is turned off, the silicon carbide field effect transistor Q5 is in the on state. The drive current amplification circuit includes a first transistor Q1, wherein the base of the first transistor Q1 is connected to the drain of the first field-effect transistor Q3 via a fourth resistor R4, and the collector of the first transistor Q1 is connected to the gate of the silicon carbide field-effect transistor Q5 via a fifth resistor R5. A second resistor R2 is provided between the base and the emitter of the first transistor Q1, so that when the first field-effect transistor Q3 is turned on and the second field-effect transistor Q4 is turned off, a voltage is applied between the second resistor R2 and the fourth resistor R4, thereby turning on the first transistor Q1. The invention also includes a fast shutdown circuit, wherein the fast shutdown circuit includes a second transistor Q2, the collector of the second transistor Q2 is connected to the base of the first transistor Q1, the emitter of the second transistor Q2 is connected to the positive electrode VCC of the circuit, and the base of the second transistor Q2 is connected to the gate of the first field effect transistor Q3 and the offline controller (1) through a third resistor R3 and a capacitor C1; The third resistor R3 and the capacitor C1 form an RC time constant, and the RC time constant is 200ns; The base and emitter of the second transistor Q2 are connected via a first resistor R1; The diode D1 is connected between the third resistor R3 and the capacitor C1 , and an anode of the diode D1 is connected to the circuit positive electrode VCC or the circuit negative electrode GND.

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