Self-driven active bridge rectifier circuit and electronic equipment

Abstract

The invention relates to the technical field of power supplies, and discloses a self-driven active bridge rectifier circuit and electronic equipment, and the circuit comprises a passive rectifier unit composed of a diode D2 and a diode D4, a switch tube Q1, a switch tube Q2, a first comparison circuit and a second comparison circuit. The positive electrode of the diode D2 is connected with the L end of the input power supply, the positive electrode of the diode D4 is connected with the N end of the input power supply, and the negative electrode is connected with a load. The drain electrode of the switch tube Q1 is connected with the L end of the input power supply, the source electrode is grounded, and the grid electrode is connected with the output end of the first comparison circuit. A first input end of the first comparison circuit is connected with an N end of an input power supply, and a second input end is connected with reference voltage. The drain electrode of the switch tube Q2 is connected with the N end of the input power supply, the source electrode is grounded, and the grid electrode is connected with the output end of the second comparison circuit. The first input end of the second comparison circuit is connected with the L end of the input power supply, and the second input end of the second comparison circuit is connected with reference voltage. The rectifying circuit can further improve the power density of the power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a self-driven active bridge rectifier circuit and electronic equipment. Background Art

[0002] Active rectifier circuits have lower forward voltage drop, so they have lower rectification loss and higher rectification efficiency than passive rectifier circuits. As electronic devices develop towards miniaturization, thinness and high efficiency, the power density requirements for power modules are getting higher and higher. Existing active rectifier circuits often have more complex drive circuits, which makes it difficult to meet the increasingly high power density requirements. Therefore, it is necessary to design a new active rectifier circuit solution. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a self-driven active bridge rectifier circuit, which can reduce the complexity of the circuit, reduce the area of ​​the driving circuit, thereby reducing the heat dissipation requirements and volume of the circuit, help to improve the power density of the power supply, and conform to the compact and energy-saving design concept of modern electronic equipment.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: a self-driven active bridge rectifier circuit, comprising a passive rectifier unit, a switch tube Q1, a switch tube Q2, a first comparison circuit and a second comparison circuit, the passive rectifier unit comprising a diode D2 and a diode D4, the positive electrode of the diode D2 is connected to the L end of the input power supply, the negative electrode of the diode D2 is connected to the positive electrode of the load, the positive electrode of the diode D4 is connected to the N end of the input power supply, the negative electrode of the diode D4 is connected to the positive electrode of the load, the negative electrode of the load is grounded, the drain of the switch tube Q1 is connected to the L end of the input power supply, the source of the switch tube Q1 is grounded, the gate of the switch tube Q1 is connected to the output end of the first comparison circuit, the first input end of the first comparison circuit is connected to the N end of the input power supply, the second input end of the first comparison circuit is connected to a reference voltage, the drain of the switch tube Q2 is connected to the N end of the input power supply, the source of the switch tube Q2 is grounded, the gate of the switch tube Q2 is connected to the output end of the second comparison circuit, the first input end of the second comparison circuit is connected to the L end of the input power supply, and the second input end of the second comparison circuit is connected to a reference voltage.

[0005] Compared with the prior art, the beneficial effects of the present invention are: by combining passive devices and a small number of active devices to form a rectifier bridge to rectify the input AC power, by combining active devices with passive devices, utilizing the characteristics of lower equivalent resistance when the active devices are turned on, the rectification loss of the entire circuit is reduced, thereby having a higher rectification efficiency than a pure passive rectification circuit, and because only two active devices are used, the driving circuit area is smaller than that of a complete active rectification circuit. At the same time, the rectifier circuit detects the waveform change of the input voltage through two comparison circuits to realize self-driving of the two active devices, further reducing the complexity of the driving circuit, and can realize self-driving of the active devices, reducing the cost, area and heat dissipation requirements of the entire circuit, and helping to improve the power density of the power supply.

[0006] In the above self-driven active bridge rectifier circuit, the passive rectifier unit is a rectifier bridge DB1, two input ends of the rectifier bridge DB1 are respectively connected to the L end and the N end of the input power supply, and the output end of the rectifier bridge DB1 is connected to the load.

[0007] The above-mentioned self-driven active bridge rectifier circuit, the first comparison circuit includes a comparator U1A, a plurality of resistors and a diode D1, the non-inverting input terminal of the comparator U1A is connected to the working voltage through a resistor R3, and is connected to the positive electrode of the diode D1 through a resistor R4, the inverting input terminal of the comparator U1A is connected to the working voltage through a resistor R1, and is grounded through a resistor R2, and the cathode of the diode D1 is connected to the N terminal of the input power supply.

[0008] In the above self-driven active bridge rectifier circuit, capacitor C1 is connected in parallel across the two ends of resistor R2.

[0009] In the above self-driven active bridge rectifier circuit, the non-inverting input terminal of the comparator U1A is also grounded through the capacitor C2.

[0010] In the above-mentioned self-driven active bridge rectifier circuit, the second comparison circuit includes a comparator U1B, a plurality of resistors and a diode D3. The non-inverting input terminal of the comparator U1B is connected to the working voltage through a resistor R7, and is connected to the positive electrode of the diode D3 through a resistor R8. The inverting input terminal of the comparator U1B is connected to the inverting input terminal of the comparator U1A, and the cathode of the diode D3 is connected to the L terminal of the input power supply.

[0011] In the above self-driven active bridge rectifier circuit, the non-inverting input terminal of the comparator U1B is also grounded through the capacitor C4.

[0012] In the above self-driven active bridge rectifier circuit, the gate of the switch tube Q1 is connected to the working voltage through the resistor R5, and a resistor R6 is provided between the gate and the source of the switch tube Q1.

[0013] In the above self-driven active bridge rectifier circuit, the gate of the switch tube Q2 is connected to the working voltage through the resistor R9, and a resistor R10 is provided between the gate and the source of the switch tube Q2.

[0014] An electronic device comprises the above-mentioned self-driven active bridge rectifier circuit.

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. 4 is a schematic diagram of a self-driven active bridge rectifier circuit according to a first embodiment of the present invention.

[0017] Figure 2 FIG. 4 is a schematic diagram of a self-driven active bridge rectifier circuit according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below. Figure 1 , an embodiment of the present invention provides a self-driven active bridge rectifier circuit, including a diode D2, a diode D4, a switch tube Q1, a switch tube Q2, a first comparison circuit and a second comparison circuit. The positive electrode of the diode D2 is connected to the L end of the input power supply, the negative electrode of the diode D2 is connected to the positive electrode of the load, the positive electrode of the diode D4 is connected to the N end of the input power supply, the negative electrode of the diode D4 is connected to the positive electrode of the load, and the negative electrode of the load is grounded. The drain of the switch tube Q1 is connected to the L end of the input power supply, the source is grounded, and the gate is connected to the output end of the first comparison circuit. The first input end of the first comparison circuit is connected to the input power supply through the forward diode D1 and the N end of the input power supply, and the second input end is connected to the reference voltage. The drain of the switch tube Q2 is connected to the N end of the input power supply, the source is grounded, and the gate is connected to the output end of the second comparison circuit. The first input end of the second comparison circuit is connected to the L end of the input power supply through the forward diode D3, and the second input end of the second comparison circuit is connected to the reference voltage.

[0019] In the self-driven active bridge rectifier circuit, when the input voltage is in the positive half cycle, the voltage value of the in-phase input terminal of the first comparison circuit is always less than 0V, and the voltage value of the first input terminal of the first comparison circuit is always less than its second input terminal, so the first comparison circuit outputs a low level, and the switch tube Q1 remains off. The voltage value of the in-phase input terminal of the second comparison circuit will increase from 0V and then decrease as the positive half cycle of the input alternating current changes. When it increases to a value higher than the reference voltage input at its inverting input terminal, the second comparison circuit outputs a high level, the switch tube Q2 is turned on, and the input voltage forms a complete power supply circuit through the diode D2, the load and the switch tube Q2. When the input voltage is in the negative half cycle, vice versa, the switch tube Q1 is turned on under the control of the first comparison circuit, and the input voltage forms a complete power supply circuit through the diode D4, the load and the switch tube Q1. The self-driven active bridge rectifier circuit rectifies the input voltage by combining two passive devices and two active devices into a rectifier bridge, thereby reducing the number of active devices and thus reducing the complexity of the drive circuit. At the same time, two comparison circuits are used to detect the waveform changes of the input voltage to realize self-driving of the two active devices, further reducing the complexity of the driving circuit. The self-driven active bridge rectifier circuit realizes the rectification of the input voltage by combining passive devices with a small number of active devices, avoiding excessive rectification losses during the rectification process while ensuring a certain rectification efficiency, and has a smaller circuit area, reducing the heat dissipation requirements and manufacturing costs of the circuit, which is conducive to improving the power density of the power supply and is more in line with the compact and energy-saving design concept of modern electronic equipment.

[0020] Reference Figure 1 In this embodiment, the reference voltages of the first comparison circuit and the second comparison circuit have the same value. The first comparison circuit includes a comparator U1A, a plurality of resistors and a diode D1. The non-inverting input terminal of the comparator U1A is connected to the operating voltage VCC through a resistor R3, and is connected to the positive electrode of the diode D1 through a resistor R4. The inverting input terminal of the comparator U1A is connected to the operating voltage VCC through a resistor R1, and is grounded through a resistor R2, and the negative electrode of the diode D1 is connected to the N terminal of the input power supply. The second comparison circuit includes a comparator U1B, a plurality of resistors and a diode D3. The non-inverting input terminal of the comparator U1B is connected to the operating voltage VCC through a resistor R7, and is connected to the positive electrode of the diode D3 through a resistor R8. The inverting input terminal of the comparator U1B is connected to the inverting input terminal of the comparator U1A, and the negative electrode of the diode D3 is connected to the L terminal of the input power supply.

[0021] When the input voltage is in the positive half cycle, the voltage value of the input voltage gradually increases from 0V and then gradually decreases to 0V. When the input voltage value is 0V, the diode D3 is turned on, and the value of the in-phase input terminal of the comparator U1B is the sum of the value of the working voltage VCC divided by the resistors R7 and R8 and the conduction voltage of the diode D3 (usually about 0.7V). At this time, the voltage value of the in-phase input terminal of the comparator U1B is lower than the value of the preset reference voltage input to its inverting input terminal. The comparator U1B outputs a low level and the switch tube Q2 is turned off; then the value of the input voltage gradually increases with the change of the sine curve. When the value of the input voltage is less than the working voltage V CC, the voltage value of the non-inverting input terminal of the comparator U1B is the sum of the current input voltage value and the conduction voltage value of the diode D3. When the voltage value of the non-inverting input terminal of the comparator U1B is higher than the reference voltage input to its inverting input terminal, the comparator U1B outputs a high level and the switch tube Q1 is turned on; when the input voltage value continues to increase to be greater than the operating voltage VCC, the diode D3 is reversely cut off. At this time, the voltage value of the non-inverting input terminal of the comparator U1B is basically equal to the operating voltage VCC, and is stably higher than the preset reference voltage value of the inverting input terminal of the comparator U1B. The comparator U1B stably outputs a high level, so that the switch tube Q2 is stably turned on. When half of the positive half cycle has passed, the value of the input voltage gradually decreases to below the operating voltage VCC following the change of the sine curve, and the voltage value of the non-inverting input terminal of the comparator U1B is lower than the reference voltage value of its inverting input terminal again. When the voltage value of the non-inverting input terminal of the comparator U1B gradually decreases to below the reference voltage of the inverting input terminal following the change of the sine wave of the input voltage, the comparator U1B outputs a low level again, and the switch tube Q2 is turned off. Similarly, when the input voltage is in the negative half cycle, the first switch circuit controls the switch tube Q1 to turn on or off according to the waveform change of the input voltage. In this way, as the sine wave of the input voltage changes, the switch tube Q1 and the switch tube Q2 are cyclically complementarily turned on under the control of the first comparison circuit and the second comparison circuit, respectively, to achieve self-driving control of the entire rectifier circuit. In this embodiment, the reference voltages of the first comparison circuit and the second comparison circuit are obtained by dividing the working voltage VCC by resistors R1 and R2. The dead time of switching between the switch tubes Q1 and Q2 can be flexibly adjusted by adjusting the resistance values ​​of the resistors R1, R2, R3, R4, R8 and R7 to avoid the switch tubes Q1 and Q2 being turned on at the same time. The zero-crossing position of the input voltage is detected by diodes D3 and D4, so that the switch tubes Q1 and Q2 can perform switching action when the input voltage is close to 0V, reducing switching losses and further improving the rectification efficiency of the circuit.

[0022] Reference Figure 1In this embodiment, in order to ensure the stability of the voltage input to the comparators U1A and U1B, the non-inverting input terminal of the comparator U1A is grounded through a capacitor C2, the non-inverting input terminal of the comparator U1B is grounded through a capacitor C4, and a capacitor C1 is connected in parallel to both ends of the resistor R2.

[0023] Reference Figure 1 In this embodiment, in order to protect the switch tubes Q1 and Q2 and to ensure that the switch tubes Q1 and Q2 can be stably turned on and off, the gate of the switch tube Q1 is connected to the working voltage VCC through the resistor R5, and a resistor R6 is provided between the gate and the source of the switch tube Q1, and the gate of the switch tube Q2 is connected to the working voltage VCC through the resistor R9, and a resistor R10 is provided between the gate and the source of the switch tube Q2. It can be understood that in some embodiments, the comparators U1A and U1B can be replaced by operational amplifiers, and in this case, the resistors R5 and R9 can be omitted.

[0024] It is understandable that, in some embodiments, the passive rectifier unit may also directly use a rectifier bridge chip. Figure 2 As shown, the two input ends of the rectifier bridge DB1 are connected to the L end and the N end of the input power supply respectively, and the output end of the rectifier bridge DB1 is connected to the load. During operation, since the resistance of the switch tubes Q1 and Q2 is smaller after being turned on, the current will still flow through the switch tubes Q1 and Q2 first, thereby reducing the conduction loss of the rectifier circuit and improving the rectification efficiency.

[0025] The electronic device of the embodiment of the present invention includes the above-mentioned self-driven active bridge rectifier circuit, which can improve the power density of the device with lower manufacturing cost and heat dissipation requirements, and contribute to the miniaturization and lightweight design of the electronic device.

[0026] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They 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 or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0027] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0029] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A self-driven active bridge rectifier circuit, characterized in that: The invention comprises a passive rectification unit, a switch tube Q1, a switch tube Q2, a first comparison circuit and a second comparison circuit. The passive rectification unit comprises a diode D2 and a diode D4. The positive electrode of the diode D2 is connected to the L end of the input power supply, the negative electrode of the diode D2 is connected to the positive electrode of the load, the positive electrode of the diode D4 is connected to the N end of the input power supply, the negative electrode of the diode D4 is connected to the positive electrode of the load, the negative electrode of the load is grounded, the drain of the switch tube Q1 is connected to the L end of the input power supply, the source of the switch tube Q1 is grounded, the gate of the switch tube Q1 is connected to the output end of the first comparison circuit, the first input end of the first comparison circuit is connected to the N end of the input power supply, the second input end of the first comparison circuit is connected to a reference voltage, the drain of the switch tube Q2 is connected to the N end of the input power supply, the source of the switch tube Q2 is grounded, the gate of the switch tube Q2 is connected to the output end of the second comparison circuit, the first input end of the second comparison circuit is connected to the L end of the input power supply, and the second input end of the second comparison circuit is connected to a reference voltage.

2. The self-driven active bridge rectifier circuit according to claim 1, characterized in that: The passive rectifying unit is a rectifier bridge DB1, two input ends of the rectifier bridge DB1 are respectively connected to the L end and the N end of the input power supply, and the output end of the rectifier bridge DB1 is connected to the load.

3. The self-driven active bridge rectifier circuit according to claim 1 or 2, characterized in that: The first comparison circuit includes a comparator U1A, a plurality of resistors and a diode D1. The non-inverting input terminal of the comparator U1A is connected to the working voltage through a resistor R3 and is connected to the positive electrode of the diode D1 through a resistor R4. The inverting input terminal of the comparator U1A is connected to the working voltage through a resistor R1 and is grounded through a resistor R2. The cathode of the diode D1 is connected to the N terminal of the input power supply.

4. The self-driven active bridge rectifier circuit according to claim 3, characterized in that: The two ends of the resistor R2 are connected in parallel with the capacitor C1.

5. The self-driven active bridge rectifier circuit according to claim 3, characterized in that: The non-inverting input of comparator U1A is also connected to ground via capacitor C2.

6. The self-driven active bridge rectifier circuit according to claim 3, characterized in that: The second comparison circuit includes a comparator U1B, a plurality of resistors and a diode D3. The non-inverting input terminal of the comparator U1B is connected to the working voltage through a resistor R7 and is connected to the positive electrode of the diode D3 through a resistor R8. The inverting input terminal of the comparator U1B is connected to the inverting input terminal of the comparator U1A, and the cathode of the diode D3 is connected to the L terminal of the input power supply.

7. The self-driven active bridge rectifier circuit according to claim 6, characterized in that: The non-inverting input of comparator U1B is also connected to ground via capacitor C4.

8. The self-driven active bridge rectifier circuit according to claim 1 or 2, characterized in that: The gate of the switch tube Q1 is connected to the working voltage through the resistor R5, and a resistor R6 is provided between the gate and the source of the switch tube Q1.

9. The self-driven active bridge rectifier circuit according to claim 1 or 2, characterized in that: The gate of the switch tube Q2 is connected to the working voltage through the resistor R9, and a resistor R10 is provided between the gate and the source of the switch tube Q2.

10. An electronic device, characterized in that: It comprises the self-driven active bridge rectifier circuit according to any one of claims 1 to 9.

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