WO2020062963A1

WO2020062963A1 - Bridge drive circuit on inverter

Info

Publication number: WO2020062963A1
Application number: PCT/CN2019/092344
Authority: WO
Inventors: 徐新华; 唐锋
Original assignee: 广东百事泰电子商务股份有限公司
Priority date: 2018-09-28
Filing date: 2019-06-21
Publication date: 2020-04-02

Abstract

Disclosed in the present invention is a bridge drive circuit on an inverter, comprising a charging circuit and a drive circuit, wherein the charging circuit comprises a first diode D1 and a first capacitor C2, and the charging circuit is used to charge the first capacitor C2 by means of a first supply voltage so as to supply a second supply voltage by means of the first capacitor C2; the drive circuit comprises a first transistor Q2, and a collector of the first transistor Q2 is also connected to a controlled end of an upper bridge transistor Q3 of a bridge-type inverter circuit and is used for driving the connection or disconnection of the upper bridge transistor Q3 of the bridge-type inverter circuit by means of the second supply voltage outputted by the first capacitor C2. The bridge drive circuit on an inverter of the present invention is simple, highly reliable, has low overall power and low production costs. At the same time, the bridge drive circuit on an inverter may prevent the upper bridge transistor Q3 and a lower bridge transistor Q5 from directly connecting.

Description

Inverter upper bridge drive circuit

Technical field

The invention relates to the technical field of power supplies, and in particular, to an inverter upper-bridge driving circuit.

Background technique

The N-type switching tube or bridge circuit commonly used in power electronics is used as an electronic switch. The switching tube works in the switching mode. The source (or emitter) of the lower tube is connected to the power supply ground. The gate level is relative to the source (or (Emitter), although there is a change, but the amplitude is small. The drain of the upper tube (or collector) is positively connected to the power supply. During operation, the potential of the drain (or collector) is constant, while the source (or emitter) of the upper tube is negative (or positive) from ground to positive. Or the power supply is in high-speed transition to ground. The above working characteristics determine that the upper tube drive is a difficult point and a key point of the bridge circuit design, and its reliability determines the reliability of the entire converter.

Referring to FIG. 1 and FIG. 2, a common upper tube driving circuit in the prior art mainly includes a driving circuit using an optocoupler isolated drive or a transformer isolated driving. The use of optocoupler isolated drive or transformer isolated drive circuit has higher cost and larger volume.

Summary of the Invention

The present invention aims to solve at least one of the technical problems in the related technology. Therefore, an object of the present invention is to provide an inverter upper-bridge driving circuit.

In order to achieve the above object, an inverter upper-bridge driving circuit according to an embodiment of the present invention includes a charging circuit, the charging circuit includes a first diode D1 and a first capacitor C2, and an anode of the first diode D1 Connected to the first supply voltage, the cathode of the first diode D1 is connected to one end of the first capacitor C2, and the other end of the first capacitor C2 is connected to the upper bridge transistor Q3, The common terminal of the bridge transistor Q5 is connected, and the charging circuit is configured to charge the first capacitor C2 through the first power supply voltage to provide a second power supply voltage through the first capacitor C2; The circuit includes a first transistor Q2, a base of the first transistor Q2 is connected to a signal output terminal of a signal source, and a collector of the first transistor Q2 is connected to the first diode D1 and the first diode D1 through a first resistor R3. A common terminal of a capacitor C2 is connected, an emitter of the first transistor Q2 is connected to a reference ground, and a collector of the first transistor Q2 is also connected to a controlled terminal of an upper bridge transistor Q3 of the bridge inverter circuit. For output through the first capacitor C2 The second supply voltage drives the upper-bridge transistor Q3 of the bridge inverter circuit to be turned on or off.

Optionally, according to an embodiment of the present invention, the driving circuit further includes a level conversion circuit. The base of the first transistor Q2 is connected to the signal source output terminal through the level conversion circuit. The level shift circuit includes a second transistor Q1, a base of the second transistor Q1 is connected to the signal source, an emitter of the second transistor Q1 is connected to the reference ground, and The collector is connected to the output terminal of the first supply voltage through a second resistor R2, and the collector of the second transistor Q1 is also connected to the base of the first transistor Q2.

Optionally, according to an embodiment of the present invention, the first transistor Q2 and the second transistor Q1 are NPN-type transistors, respectively.

Optionally, according to an embodiment of the present invention, the method further includes:

A third resistor R4, one end of the third resistor R4 is connected to the collector of the first transistor Q2, and the other end of the third resistor R4 is connected to the receiver of the upper bridge transistor Q3 of the bridge inverter circuit. Console connection.

Optionally, according to an embodiment of the present invention, a fourth resistor R6 is further included. One end of the fourth resistor R6 is connected to the controlled end of the upper-bridge transistor Q3 of the bridge inverter circuit. The other end of the resistor R6 is connected to a common terminal of the upper bridge transistor Q3 and the lower bridge transistor Q5 of the bridge inverter circuit.

In the inverter upper bridge driving circuit provided by the present invention, when the lower bridge transistor Q5 of the bridge inverter circuit is turned on through the charging circuit, the first power supply voltage passes through the first diode D1, the lower bridge transistor Q5, and the reference ground pair. The first capacitor C2 is charged, and the driving power supply voltage of the switching tube is provided through the first capacitor C2. This driving circuit has a simple power supply mode circuit and high reliability.

The logic design of the driving circuit is such that when the first transistor Q2 is turned on, the high-side transistor Q3 is turned off, and when the first transistor Q2 is turned off, the high-side transistor Q3 is turned on. When the high-side transistor Q3 is turned on, because the first transistor Q2 is in an off state, the entire high-side drive circuit consumes low electrodes, and a smaller first capacitor C2 can be selected. The overall power of the driving circuit is low, the reliability is high, and the production cost is low.

By adjusting the resistance values of the first resistor R3 and the third resistor R4, the charging process of the gate of the high-side transistor Q3 can be implemented slowly. There is a certain lag, this process can avoid the shoot-through of the upper-bridge transistor Q3 and the lower-bridge transistor Q5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of an inverter upper bridge driving circuit using an optocoupler in the prior art; FIG.

FIG. 2 is a schematic structural diagram of an inverter upper-bridge driving circuit using a transformer in the prior art; FIG.

FIG. 3 is a schematic structural diagram of an upper bridge driving circuit according to an embodiment of the present invention.

Reference signs:

Signal source 10;

Inverter upper bridge driving circuit 20;

Bridge type inverter circuit 30.

The realization of the purpose, functional characteristics and advantages of the present invention will be further explained with reference to the embodiments and the drawings.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they independent or alternative embodiments that are mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

Referring to FIG. 3, the present invention provides an inverter upper-bridge driving circuit including a charging circuit and a driving circuit. The charging circuit includes a first diode D1 and a first capacitor C2. The first diode D1 Is connected to the first supply voltage + 12V, the cathode of the first diode D1 is connected to one end of the first capacitor C2, and the other end of the first capacitor C2 is connected to the upper bridge of the bridge inverter circuit A common terminal of the transistor Q3 and the lower-bridge transistor Q5 is connected, and the charging circuit is configured to charge the first capacitor C2 through the first power supply voltage + 12V to provide a second power supply voltage through the first capacitor C2; Since the upper bridge transistor Q3 of the bridge inverter is a high-level on-MOS transistor, the drain of the upper bridge transistor Q3 is electrically connected to the first high voltage. When the gate and source of the upper bridge transistor Q3 are electrically connected, When the voltage is higher than the conduction value, the upper-bridge transistor Q3 is turned on. In the embodiment of the present invention, when the lower-bridge transistor Q5 of the bridge inverter is turned on, the first capacitor C2 and the reference The ground is connected to GND, and the first power supply voltage + 12V is connected to the first through the first diode D1. Capacitor C2 is charged, when the first capacitor C2 is fully charged, the voltage across the first capacitance value C2 of the first supply voltage + 12V of voltage.

The driving circuit includes a first transistor Q2, a base of the first transistor Q2 is connected to a signal output terminal of a signal source, and a collector of the first transistor Q2 is connected to the first diode through a first resistor R3. D1, the common terminal of the first capacitor C2 is connected, the emitter of the first transistor Q2 is connected to the reference ground GND, and the collector of the first transistor Q2 is also connected to the upper bridge transistor Q3 of the bridge inverter circuit The controlled end is connected to drive the upper bridge transistor Q3 of the bridge inverter circuit to be turned on or off by the second power supply voltage output from the first capacitor C2. When the first transistor Q2 is turned off, the first capacitor C2 provides the second supply voltage to the upper-bridge transistor Q3 through the first resistor R3, and the second supply voltage acts on the The gate-source voltage of the bridge transistor Q3 and the gate-source voltage of the upper-bridge transistor Q3 are higher than the on-gate voltage, and the upper-bridge transistor Q3 is turned on. At the same time, the lower-bridge transistor Q5 is in an off state, and the source voltage of the upper-bridge transistor Q3 is close to the drain voltage. That is, the drain of the high-side transistor Q3 is in a high voltage state when the high-side transistor Q3 is turned on. Since the other end of the first capacitor C2 is connected to the source of the high-side transistor Q3, the first The two ends of a capacitor C2 are also in a high voltage state, and the first diode D1 is turned off in the reverse direction to prevent the high voltage of the first capacitor C2 from reversely charging the first power supply voltage + 12V.

When the first transistor Q2 is turned on, the collector of the first transistor Q2 is connected to the reference ground GND, the collector voltage of the first transistor Q2 is close to the reference ground GND voltage, and the gate and source of the high-side transistor Q3 The voltage is lower than the on-gate voltage, and the high-side transistor Q3 is turned off.

The inverter upper bridge driving circuit provided by the present invention passes the charging circuit through the lower bridge transistor Q5 of the bridge inverter circuit, and the first power supply voltage + 12V passes through the first diode D1, the lower bridge transistor Q5 and The first capacitor C2 is charged with reference to GND, and the driving power supply voltage of the switching tube is provided through the first capacitor C2. This driving circuit has a simple power supply mode circuit and high reliability.

The logic design of the driving circuit is such that when the first transistor Q2 is turned on, the high-side transistor Q3 is turned off, and when the first transistor Q2 is turned off, the high-side transistor Q3 is turned on. When the high-side transistor Q3 is turned on, because the first transistor Q2 is in an off state, the entire high-side drive circuit consumes low electrodes, and a smaller first capacitor C2 can be selected. When the high-side transistor Q3 is turned off, the first transistor Q2 is in an on state. At this time, the first resistor R3 needs to consume a part of energy, and is directly powered by the first power supply voltage + 12V, and does not need to consume energy on the first capacitor C2. The overall power of the driving circuit is low, the reliability is high, and the production cost is low.

Referring to FIG. 3, the driving circuit further includes a level conversion circuit. The base of the first transistor Q2 is connected to the signal source output terminal through the level conversion circuit. The level conversion circuit includes a second Transistor Q1, the base of the second transistor Q1 is connected to the signal source, the emitter of the second transistor Q1 is connected to the reference ground GND, and the collector of the second transistor Q1 is connected through a second resistor R2 It is connected to the output terminal of the first power supply voltage + 12V, and the collector of the second transistor Q1 is also connected to the base of the first transistor Q2. When the signal source outputs a high level, the collector of the second transistor Q1 is connected to a reference ground GND, and the collector of the second transistor Q1 outputs a low level. When the signal source outputs a low level, all The second transistor Q1 is turned off, the collector of the second transistor Q1 is connected to the first power supply voltage + 12V through the second resistor R2, and the collector of the second transistor Q1 outputs a high level. An output level of the signal source is inverted by the second transistor Q1. So that the driving circuit outputs a driving signal with the same phase as the signal source.

In one embodiment of the present invention, the first transistor Q2 and the second transistor Q1 are NPN-type transistors, respectively.

Referring to FIG. 3, a third resistor R4 is also included, one end of the third resistor R4 is connected to the collector of the first transistor Q2, and the other end of the third resistor R4 is connected to the bridge inverter circuit. The controlled end of the high-side transistor Q3 is connected. The first resistor R3 and the third resistor R4 are set between the output terminal of the second supply voltage and the output terminal of the upper-bridge transistor Q3, so as to limit the driving current of the upper-bridge transistor Q3. By matching the resistance values of the first resistor R3 and the third resistor R4, the on-speed of the upper-bridge transistor Q3 is slow and the off-speed is fast, thereby avoiding the through-connection of the upper and lower switching tubes of the same bridge arm. Because the resistance of the first resistor R3 and the third resistor R4 is large, the charging process of the gate of the high-side transistor Q3 is slower. The on-time of the high-side transistor Q3 is compared with the on-time of the signal source. There is a certain lag, this process can avoid the shoot-through of the upper-bridge transistor Q3 and the lower-bridge transistor Q5. Since the inverter works in the power frequency state, the frequency is relatively low, and this process will not cause the heating problem of the high-side transistor Q3 due to its slow conduction speed. The heat generated by the slow-on of the high-side transistor Q3 is negligible compared to the heat generated by the on-state loss of the high-side transistor Q3.

Referring to FIG. 3, a fourth resistor R6 is further included, one end of the fourth resistor R6 is connected to the controlled end of the upper-bridge transistor Q3 of the bridge inverter circuit, and the other end of the fourth resistor R6 is connected to the The common ends of the upper bridge transistor Q3 and the lower bridge transistor Q5 of the bridge inverter circuit are connected. The fourth resistor R6 is used to initialize and reset the controlled end of the upper-bridge transistor Q3. The fourth resistor R6 is a pull-down resistor, and is connected to a common terminal of the upper-bridge transistor Q3 and the lower-bridge transistor Q5 through the fourth resistor R6. When the first transistor Q2 does not drive an output signal, the fourth resistor R6 releases the power of the controlled end of the high-bridge transistor Q3, so that the controlled end of the high-bridge transistor Q3 is at a low level. The high-side transistor Q3 is in an initial state of being turned off.

The above are only embodiments of the present invention, but do not limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still implement the foregoing specific implementations. The technical solutions described in the methods are modified, or some technical features are replaced equivalently. Any equivalent structure made by using the description and drawings of the present invention, directly or indirectly, used in other related technical fields is equally within the scope of patent protection of the present invention.

In the description of this specification, the description with reference to the terms “one embodiment”, “some embodiments”, “examples”, “specific examples”, or “some examples” and the like means specific features described in conjunction with the embodiments or examples , Structure, material, or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limitations on the present invention. Those skilled in the art will not depart from the principles and purposes of the present invention. In the case of the present invention, changes, modifications, replacements, and variations can be made to the above embodiments within the scope of the present invention.

Claims

An inverter upper-bridge driving circuit, comprising:

The charging circuit includes a first diode D1 and a first capacitor C2, an anode of the first diode D1 is connected to a first power supply voltage, and a cathode of the first diode D1 is connected to the first diode D1. One end of a first capacitor C2 is connected, and the other end of the first capacitor C2 is connected to a common terminal of an upper bridge transistor Q3 and a lower bridge transistor Q5 of a bridge inverter circuit, and the charging circuit is configured to supply power through the first Charging the first capacitor C2 with a voltage to provide a second power supply voltage through the first capacitor C2;

The driving circuit includes a first transistor Q2, a base of the first transistor Q2 is connected to a signal output terminal of a signal source, and a collector of the first transistor Q2 is connected to the first transistor through a first resistor R3. The common terminal of the diode D1 and the first capacitor C2 is connected, the emitter of the first transistor Q2 is connected to the reference ground, and the collector of the first transistor Q2 is also connected to the upper bridge transistor of the bridge inverter circuit The controlled end of Q3 is connected to drive the on-bridge transistor Q3 of the bridge inverter circuit to be turned on or off by the second power supply voltage output from the first capacitor C2.
The inverter upper-bridge driving circuit according to claim 1, wherein the driving circuit further comprises a level conversion circuit, and a base of the first transistor Q2 is connected to the A signal source output terminal is connected, the level shift circuit includes a second transistor Q1, a base of the second transistor Q1 is connected to the signal source, and an emitter of the second transistor Q1 is connected to the reference ground, A collector of the second transistor Q1 is connected to an output terminal of the first power supply voltage through a second resistor R2, and a collector of the second transistor Q1 is also connected to a base of the first transistor Q2.
The inverter upper-bridge driving circuit according to claim 2, wherein the first transistor Q2 and the second transistor Q1 are NPN-type transistors, respectively.
The inverter upper-bridge driving circuit according to claim 1, further comprising:

A third resistor R4, one end of the third resistor R4 is connected to the collector of the first transistor Q2, and the other end of the third resistor R4 is connected to the receiver of the upper bridge transistor Q3 of the bridge inverter circuit. Console connection.
The inverter upper bridge driving circuit according to claim 1, further comprising a fourth resistor R6, one end of the fourth resistor R6 and a controlled upper bridge transistor Q3 of the bridge inverter circuit. The other end of the fourth resistor R6 is connected to a common terminal of an upper bridge transistor Q3 and a lower bridge transistor Q5 of the bridge inverter circuit.