A self-driven active bridge rectifier circuit and an electronic device

Abstract

The present invention relates to the field of power supply technologies, and discloses a self-driven active bridge rectifier circuit and an electronic device. The circuit includes a passive rectifier unit composed of diode D2 and diode D4, switching transistor Q1, switching transistor Q2, a first comparison circuit, and a second comparison circuit. The positive electrode of diode D2 is connected to the L terminal of the input power supply, the positive electrode of diode D4 is connected to the N terminal of the input power supply, and the negative electrodes are both connected to the load. The drain of switching transistor Q1 is connected to the L terminal of the input power supply, the source is grounded, and the gate is connected to the output terminal of the first comparison circuit. The first input terminal of the first comparison circuit is connected to the N terminal of the input power supply, and the second input terminal is connected to a reference voltage. The drain of switching transistor Q2 is connected to the N terminal of the input power supply, the source is grounded, and the gate is connected to the output terminal of the second comparison circuit. The first input terminal of the second comparison circuit is connected to the L terminal of the input power supply, and the second input terminal of the second comparison circuit is connected to a reference voltage. This rectifier 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 supplies, and particularly relates to a self-driven active bridge rectifier circuit and an electronic device. Background Art

[0002] Since the active rectifier circuit has a lower forward voltage drop, it has lower rectification loss and higher rectification efficiency compared to the passive rectifier circuit. With the development of electronic devices towards miniaturization, thinness, lightness and high performance, the requirement for the power density of the power supply module is getting higher and higher. The existing active rectifier circuit often has a relatively complex drive circuit and thus it is difficult to meet the increasingly high power density requirement. Therefore, a new active rectifier circuit solution needs to be designed. Summary of the Invention

[0003] In order to overcome the deficiencies 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 drive circuit, thereby reducing the heat dissipation requirement and volume of the circuit, and contributing to improving the power density of the power supply, which is in line with the compact and energy-saving design concept of modern electronic devices.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows: A self-driven active bridge rectifier circuit includes a passive rectification unit, a switching transistor Q1, a switching transistor Q2, a first comparison circuit and a second comparison circuit. The passive rectification unit includes a diode D2 and a diode D4. The positive electrode of the diode D2 is connected to the L terminal 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 terminal 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 switching transistor Q1 is connected to the L terminal of the input power supply, the source of the switching transistor Q1 is grounded, and the gate of the switching transistor Q1 is connected to the output terminal of the first comparison circuit. The first input terminal of the first comparison circuit is connected to the N terminal of the input power supply, and the second input terminal of the first comparison circuit is connected to a reference voltage. The drain of the switching transistor Q2 is connected to the N terminal of the input power supply, the source of the switching transistor Q2 is grounded, and the gate of the switching transistor Q2 is connected to the output terminal of the second comparison circuit. The first input terminal of the second comparison circuit is connected to the L terminal of the input power supply, and the second input terminal 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 as follows: By combining passive devices and a small number of active devices to form a rectifier bridge to rectify the input alternating current, through the cooperation of active devices and passive devices, and utilizing the characteristic of the lower equivalent resistance presented when the active devices are conducting, the rectification loss of the entire circuit is reduced, so that it has a higher rectification efficiency compared with a pure passive rectification circuit. And since only two active devices are used, it has a smaller driving circuit area compared with a complete active rectification circuit. At the same time, this rectification circuit detects the waveform change of the input voltage through two comparison circuits to realize the self-driving of the two active devices, further reducing the complexity of the driving circuit, and can realize the self-driving of the active devices, reducing the cost, area and heat dissipation requirements of the entire circuit, which helps to improve the power density of the power supply.

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

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

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

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

[0010] In the above self-driven active bridge rectifier circuit, the second comparison circuit includes comparator U1B, several resistors and diode D3. The non-inverting input terminal of comparator U1B is connected to the operating voltage through resistor R7 and connected to the positive electrode of diode D3 through resistor R8. The inverting input terminal of comparator U1B is connected to the inverting input terminal of comparator U1A, and the negative electrode of 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 comparator U1B is also grounded through capacitor C4.

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

[0013] For the self-driven active bridge rectifier circuit described above, the gate of the switching transistor Q2 is connected to the operating voltage through a resistor R9, and a resistor R10 is provided between the gate and the source of the switching transistor Q2.

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

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Description of the Drawings

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

[0017] Figure 2 It is a schematic diagram of the self-driven active bridge rectifier circuit according to the second embodiment of the present invention. Specific Embodiments

[0018] The embodiments of the present invention will be described in detail below. Referring to Figure 1 In an embodiment of the present invention, a self-driven active bridge rectifier circuit is provided, which includes a diode D2, a diode D4, a switching transistor Q1, a switching transistor Q2, a first comparison circuit, and a second comparison circuit. The positive electrode of the diode D2 is connected to the L terminal 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 terminal 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 switching transistor Q1 is connected to the L terminal of the input power supply, the source is grounded, and the gate is connected to the output terminal of the first comparison circuit. The first input terminal of the first comparison circuit is connected to the input power supply through a forward diode D1 and the N terminal of the input power supply, and the second input terminal is connected to a reference voltage. The drain of the switching transistor Q2 is connected to the N terminal of the input power supply, the source is grounded, and the gate is connected to the output terminal of the second comparison circuit. The first input terminal of the second comparison circuit is connected to the L terminal of the input power supply through a forward diode D3, and the second input terminal of the second comparison circuit is connected to a reference voltage.

[0019] When the input voltage is in the positive half-cycle, the voltage value at the non-inverting input terminal of the first comparison circuit is always less than 0V, and the voltage value at the first input terminal of the first comparison circuit is always less than its second input terminal. Therefore, the first comparison circuit outputs a low level, and the switching transistor Q1 remains off. The voltage value at the non-inverting input terminal of the second comparison circuit will increase first and then decrease starting from 0V as the positive half-cycle of the input alternating current changes. When it rises above the reference voltage input to its inverting input terminal, the second comparison circuit outputs a high level, and the switching transistor Q2 conducts. The input voltage forms a complete power supply loop through the diode D2, the load, and the switching transistor Q2. When the input voltage is in the negative half-cycle, vice versa, the switching transistor Q1 conducts under the control of the first comparison circuit, and the input voltage forms a complete power supply loop through the diode D4, the load, and the switching transistor Q1. This self-driven active bridge rectifier circuit rectifies the input voltage by combining two passive devices and two active devices into a rectifier bridge, reducing the number of active devices, thereby reducing the complexity of the drive circuit. At the same time, by using two comparison circuits to detect the waveform changes of the input voltage, the self-driving of the two active devices is realized, further reducing the complexity of the drive circuit. This self-driven active bridge rectifier circuit combines passive devices and a small number of active devices to rectify the input voltage, avoiding excessive rectification losses during the rectification process, ensuring a certain rectification efficiency, having a smaller circuit area, reducing the heat dissipation requirements and manufacturing costs of the circuit, being beneficial to improving the power density of the power supply, and being more in line with the compact and energy-saving design concept of modern electronic devices.

[0020] Referring to Figure 1 , in this embodiment, the reference voltage values of the first comparison circuit and the second comparison circuit are the same. The first comparison circuit includes a comparator U1A, several 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 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 grounded through a resistor R2. 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, several 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 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 starts from 0V, gradually increases first and then gradually decreases to 0V. When the value of the input voltage is 0V, the diode D3 conducts, and the value at the non-inverting input terminal of the comparator U1B is the sum of the value obtained by dividing the operating voltage VCC by resistors R7 and R8 and the conduction voltage of the diode D3 (usually about 0.7V). At this time, the voltage value at the non-inverting input terminal of the comparator U1B is lower than the value of the preset reference voltage input to its inverting input terminal, and the comparator U1B outputs a low level, turning off the switching transistor Q2; subsequently, the value of the input voltage gradually increases as the sine curve changes. When the value of the input voltage is less than the operating voltage VCC, the voltage value at 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 at 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, turning on the switching transistor Q1; when the value of the input voltage continues to increase to be greater than the operating voltage VCC, the diode D3 is reverse cut-off. At this time, the voltage value at the non-inverting input terminal of the comparator U1B is basically equal to the operating voltage VCC, stably higher than the value of the preset reference voltage at the inverting input terminal of the comparator U1B, and the comparator U1B stably outputs a high level, stably turning on the switching transistor Q2. When half of the positive half-cycle has passed and the value of the input voltage gradually decreases below the operating voltage VCC as the sine curve changes, the voltage value at the non-inverting input terminal of the comparator U1B is again lower than the reference voltage at its inverting input terminal. When the voltage value at the non-inverting input terminal of the comparator U1B gradually decreases below the reference voltage at the inverting input terminal as the sine wave of the input voltage changes, the comparator U1B outputs a low level again, turning off the switching transistor Q2. Similarly, when the input voltage is in the negative half-cycle, the first switching circuit controls the switching transistor Q1 to conduct or turn off according to the waveform change of the input voltage. Thus, as the sine wave of the input voltage changes, the switching transistors Q1 and Q2 are alternately and complementarily turned on under the control of the first comparison circuit and the second comparison circuit respectively, realizing the 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 both obtained by dividing the operating voltage VCC by resistors R1 and R2. The dead time for switching between the switching transistors 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 simultaneous conduction of the switching transistors Q1 and Q2. And the zero-crossing position of the input voltage is detected by the diodes D3 and D4, enabling the switching transistors Q1 and Q2 to perform switching actions when the input voltage is close to 0V, reducing the switching loss, and further improving the rectification efficiency of the circuit.

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

[0023] Referring to Figure 1 , in this embodiment, in order to protect switching transistors Q1 and Q2 and to ensure that switching transistors Q1 and Q2 can conduct and turn off stably, the gate of switching transistor Q1 is connected to the operating voltage VCC through resistor R5, and a resistor R6 is provided between the gate and the source of switching transistor Q1. The gate of switching transistor Q2 is connected to the operating voltage VCC through resistor R9, and a resistor R10 is provided between the gate and the source of switching transistor Q2. It can be understood that in some embodiments, comparators U1A and U1B can be replaced by operational amplifiers, and at this time, resistors R5 and R9 can be omitted.

[0024] It can be understood that in some embodiments, the passive rectification unit can also directly adopt a rectifier bridge chip. As Figure 2 shown, the two input terminals of rectifier bridge DB1 are respectively connected to the L terminal and the N terminal of the input power supply, and the output terminal of rectifier bridge DB1 is connected to the load. During the working process, since the resistances of switching transistors Q1 and Q2 after conduction are smaller, the current will still preferentially flow through switching transistors Q1 and Q2, thereby reducing the conduction loss of the rectification 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 rectification circuit, which can improve the power density of the device with a relatively low manufacturing cost and heat dissipation requirement, and is helpful for the miniaturization and thin-and-light design of the electronic device.

[0026] It should be noted that in the description of the present invention, if there is a description of the orientation, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., it is all based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 of the present invention.

[0027] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If there is a description of the first or the second, etc., it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0028] In the description of the present invention, unless otherwise clearly defined, terms such as "set", "install", "connect", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0029] The above-mentioned embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention belong to 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, and the gate of the switch tube Q2 is connected to the output end of the second comparison circuit. The first input terminal of the second comparison circuit is connected to the L terminal of the input power supply, and the second input terminal of the second comparison circuit is connected to the reference voltage. 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. 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.

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 two ends of the resistor R2 are connected in parallel with the capacitor C1.

4. The self-driven active bridge rectifier circuit according to claim 1 or 2, characterized in that: The non-inverting input of comparator U1A is also connected to ground via capacitor C2.

5. The self-driven active bridge rectifier circuit according to claim 1 or 2, characterized in that: The non-inverting input of comparator U1B is also connected to ground via capacitor C4.

6. 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.

7. 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.

8. An electronic device, characterized in that: It comprises the self-driven active bridge rectifier circuit according to any one of claims 1 to 7.

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