High-precision voltage-stabilizing output circuit of switching power supply

Abstract

The utility model discloses a high-precision voltage stabilization output circuit of a switching power supply, which comprises a power supply output module, an operational amplifier module and a feedback module, the output end of the power supply output module is connected with the input end of the operational amplifier module, and the output end of the operational amplifier module is connected with the input end of the feedback module. A voltage stabilization control circuit is connected between the feedback module and the power output module. When the circuit works, an output voltage generated by the power supply output module is firstly transmitted to the operational amplifier module, the operational amplifier module compares the output voltage with a voltage required by a load and then transmits a comparison result to the feedback module, and the feedback module sends a control signal to the voltage stabilization control circuit according to the voltage required by the load. The voltage stabilization control circuit carries out voltage stabilization control on the power supply output module according to the control signal transmitted by the feedback module, thereby ensuring the stability and reliability of the output voltage, and meeting the requirements of the load.

Description

Technical Field

[0001] This utility model relates to a power supply voltage regulator, and more particularly to a voltage regulator output circuit for a switching power supply. Background Technology

[0002] When faced with diverse load conditions and complex application environments, existing switching power supply modules often rely on simple feedback loops for voltage regulation, making it difficult to achieve precise and effective output voltage management. While linear regulators are commonly used to control the output voltage, their circuit structure is simple, but their ability to adapt to load changes is weak. Especially in applications requiring high-precision voltage output, these circuits, lacking sufficient adjustment finesse, may produce significant output voltage errors, failing to meet usage requirements. Utility Model Content

[0003] In order to overcome the shortcomings of the existing technology, this utility model provides a high-precision voltage regulation output circuit for a switching power supply.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A high-precision voltage regulation output circuit for a switching power supply includes a power output module, an operational amplifier module, and a feedback module. The output terminal of the power output module is connected to the input terminal of the operational amplifier module, the output terminal of the operational amplifier module is connected to the input terminal of the feedback module, and a voltage regulation control circuit is connected between the feedback module and the power output module.

[0006] The power output module includes a transformer TB. The third pin of the transformer TB is connected to the third pin of the common-mode inductor LF3 via a fast recovery diode D10. A first filter circuit consisting of a capacitor C14, a resistor R96, a resistor R97, and a resistor R98 is connected to the fast recovery diode D10. The fourth pin of the transformer TB is divided into two paths: one is grounded, and the other is connected to the fourth pin of the common-mode inductor LF3 via a resistor RCS4. The third and fourth pins of the transformer TB constitute the secondary winding. The third and fourth pins of the common-mode inductor LF3 are connected in parallel with an electrolytic capacitor C29, a resistor R59, an electrolytic capacitor C30, and a resistor R63.

[0007] A power supply regulator circuit is connected between the power output module and the operational amplifier module. The power supply regulator circuit includes a voltage reference chip U5. The second pin of the voltage reference chip U5 is divided into two paths. One path is connected to the output terminal of the power output module through resistor R77, Zener diode ZD2, Zener diode ZD1 and resistor R63. The other path is connected to the input terminal of the operational amplifier module through resistor R83. The third pin of the voltage reference chip U5 is grounded. The first pin and the second pin of the voltage reference chip U5 are connected. A capacitor C75 is connected between the second pin and the third pin of the voltage reference chip U5.

[0008] The operational amplifier module includes an operational amplifier U1. The third pin of the operational amplifier U1 is connected to a resistor R83. The second pin of the operational amplifier U1 is divided into two paths: one path is connected to the first pin of the common-mode inductor LF3 through a resistor R86, and the other path is grounded through a capacitor C76. The first pin of the operational amplifier U1 serves as the output terminal and is connected to the feedback module. A resistor R85 and a capacitor C74 are connected between the first pin and the second pin of the operational amplifier U1.

[0009] The feedback module includes an optocoupler U3. The second pin of the optocoupler U3 is divided into two paths: one path is connected to the first pin of the operational amplifier U1 through diode D24, and the other path is connected to the voltage regulation control circuit. The first pin of the optocoupler U3 is divided into two paths: one path is connected to the second pin of the optocoupler U3 through resistor R60, and the other path is connected to the third pin of the common mode inductor LF3 through switching diode ZD4 and resistor R42.

[0010] The voltage regulation control circuit includes a voltage reference chip U2. The second pin of the voltage reference chip U2 is connected to the second pin of the optocoupler U3. The third pin of the voltage reference chip U2 is grounded. The first pin of the voltage reference chip U2 is connected to the third pin of the common mode inductor LF3 through resistors R69, R66, and R67. A second filter circuit consisting of capacitors C72 and C48 and resistor R62 is connected between the first and second pins of the voltage reference chip U2. Resistors R65 and R64 are connected in parallel between the first and third pins of the voltage reference chip U2.

[0011] The beneficial effects of this utility model are as follows: This utility model includes a power output module, an operational amplifier module, and a feedback module. The output terminal of the power output module is connected to the input terminal of the operational amplifier module, and the output terminal of the operational amplifier module is connected to the input terminal of the feedback module. A voltage regulation control circuit is connected between the feedback module and the power output module. When the circuit is working, the output voltage generated by the power output module is first transmitted to the operational amplifier module, which compares the output voltage with the voltage required by the load. Then, the comparison result is transmitted to the feedback module. The feedback module sends a control signal to the voltage regulation control circuit according to the voltage required by the load. The voltage regulation control circuit performs voltage regulation control on the power output module according to the control signal from the feedback module, thereby ensuring the stability and reliability of the output voltage and meeting the load requirements. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0015] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0016] The following describes some embodiments of the present invention with reference to the accompanying drawings.

[0017] Reference Figure 1 A high-precision voltage regulation output circuit for a switching power supply includes a power output module, an operational amplifier module, and a feedback module. The output terminal of the power output module is connected to the input terminal of the operational amplifier module, the output terminal of the operational amplifier module is connected to the input terminal of the feedback module, and a voltage regulation control circuit is connected between the feedback module and the power output module.

[0018] Specifically, the power output module includes a transformer TB. Pin 3 of the transformer TB is connected to pin 3 of a common-mode inductor LF3 via a fast recovery diode D10. A first filter circuit, consisting of capacitor C14, resistors R96, R97, and R98, is connected to the fast recovery diode D10. This first filter circuit performs preliminary filtering of the output voltage. Pin 4 of the transformer TB is split into two paths: one grounded, and the other connected to pin 4 of the common-mode inductor LF3 via resistor RCS4. Pins 3 and 4 of the transformer TB form the secondary winding. Pins 3 and 4 of the common-mode inductor LF3 are connected in parallel with an electrolytic capacitor C29, resistor R59, electrolytic capacitor C30, and resistor R63 to further filter the output voltage and suppress interference. In this embodiment, pins 1 and 2 of the transformer T1B form the primary winding, used to connect to a conventional power supply circuit. The secondary winding formed by pins 3 and 4 outputs power as labeled VDD.

[0019] A power supply regulator circuit is connected between the power output module and the operational amplifier module. This power supply regulator circuit includes a voltage reference chip U5. Pin 2 of the voltage reference chip U5 is divided into two paths: one path connects to the output terminal of the power output module via resistor R77, Zener diodes ZD2 and ZD1, and resistor R63; the other path connects to the input terminal of the operational amplifier module via resistor R83. Pin 3 of the voltage reference chip U5 is grounded. Pins 1 and 2 of the voltage reference chip U5 are connected, and capacitor C75 is connected between pins 2 and 3. In this embodiment, the voltage reference chip U5 is a TL431 chip. The TL431 has high-precision voltage reference characteristics and can flexibly set the regulated voltage value. Specifically, the voltage reference chip U5, based on an internal reference, precisely regulates the output voltage to the operational amplifier module through feedback from pin 1 and voltage division by resistor R83.

[0020] The operational amplifier module includes operational amplifier U1. Pin 3 of operational amplifier U1 is connected to resistor R83, and pin 4 of operational amplifier U1 is grounded. Resistors R84 and R84A are connected in parallel between pins 3 and 4 for further voltage regulation. Pin 2 of operational amplifier U1 is split into two paths: one path is connected to pin 1 of common-mode inductor LF3 via resistor R86 to acquire the voltage required by the load; the other path is grounded via capacitor C76. Pin 1 of operational amplifier U1 serves as the output terminal and is connected to the feedback module. Resistor R85 and capacitor C74 are connected between pins 1 and 2 of operational amplifier U1. In this embodiment, the output voltage is compared with the voltage required by the load, and the comparison result is then output to the feedback module to achieve power supply regulation.

[0021] The feedback module includes an optocoupler U3. Pin 2 of the optocoupler U3 is split into two paths: one path connects to pin 1 of the operational amplifier U1 via diode D24, which limits current to prevent excessive current output and potential breakdown of the optocoupler U3; the other path connects to a voltage regulation control circuit. Pin 1 of the optocoupler U3 is also split into two paths: one path connects to pin 2 of the optocoupler U3 via resistor R60; the other path connects to pin 3 of the common-mode inductor LF3 via switching diode ZD4 and resistor R42. In this embodiment, the output signal from pin 1 of the operational amplifier U1 drives the internal light-emitting terminal of the optocoupler U2 via diode D24. The light from the light-emitting terminal triggers the receiving terminal, thus feeding the signal back to the preceding stage or participating in power supply regulation. Pins 3 and 4 of the optocoupler U3 are used to connect to the power supply regulation section of a conventional power supply circuit to feed the signal back to the power chip for signal interaction. Specifically, pin C in the figure is used to connect to the feedback pin of the power chip in power supply regulation.

[0022] The voltage regulation control circuit includes a voltage reference chip U2. Pin 2 of the voltage reference chip U2 is connected to pin 2 of the optocoupler U3, and pin 3 of the voltage reference chip U2 is grounded. Pin 1 of the voltage reference chip U2 is connected to pin 3 of the common-mode inductor LF3 via resistors R69, R66, and R67. A resistor VR1 is connected in parallel with resistor R66. A second filter circuit consisting of capacitors C72 and C48 and resistor R62 is connected between pins 1 and 2 of the voltage reference chip U2. Resistors R65 and R64 are connected in parallel between pins 1 and 3 of the voltage reference chip U2. In this embodiment, resistors R69, R66, R67, R65, and R64 are resistors with a tolerance of 0.1% to control voltage error. Additionally, the voltage reference chip U2 is a TL431 model with a control error of 0.05% to improve the accuracy of the controlled voltage and ensure that the output voltage is within the specified range.

[0023] In terms of working principle, the output voltage generated by the power output module is first transmitted to the operational amplifier module. The operational amplifier module compares the output voltage with the voltage required by the load. Specifically, when the voltage at pin 3 of the operational amplifier U1 is higher than the voltage at pin 2, that is, the output voltage is higher than the voltage required by the load, pin 1 of the operational amplifier U1 outputs a high level. At this time, pins 1 and 2 of the voltage reference chip U2 are turned on, so that resistors R69, R66 and R67 divide the output voltage, thereby ensuring that the output voltage is the same as the voltage required by the load and meets the load's requirements.

[0024] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A high-precision voltage regulated output circuit for a switching power supply, characterized in that... It includes a power output module, an operational amplifier module, and a feedback module. The output terminal of the power output module is connected to the input terminal of the operational amplifier module, the output terminal of the operational amplifier module is connected to the input terminal of the feedback module, and a voltage regulation control circuit is connected between the feedback module and the power output module.

2. The high-precision voltage regulated output circuit of the switching power supply according to claim 1, characterized in that... The power output module includes a transformer TB. The third pin of the transformer TB is connected to the third pin of the common-mode inductor LF3 via a fast recovery diode D10. A first filter circuit consisting of a capacitor C14, a resistor R96, a resistor R97, and a resistor R98 is connected to the fast recovery diode D10. The fourth pin of the transformer TB is divided into two paths: one is grounded, and the other is connected to the fourth pin of the common-mode inductor LF3 via a resistor RCS4. The third and fourth pins of the transformer TB constitute the secondary winding. An electrolytic capacitor C29, a resistor R59, and an electrolytic capacitor C30 are connected in parallel between the third and fourth pins of the common-mode inductor LF3.

3. The high-precision regulated output circuit of a switching power supply according to claim 2, characterized in that A power supply regulator circuit is connected between the power output module and the operational amplifier module. The power supply regulator circuit includes a voltage reference chip U5. The second pin of the voltage reference chip U5 is divided into two paths. One path is connected to the output terminal of the power output module through resistor R77, Zener diode ZD2, Zener diode ZD1 and resistor R63. The other path is connected to the input terminal of the operational amplifier module through resistor R83. The third pin of the voltage reference chip U5 is grounded. The first pin and the second pin of the voltage reference chip U5 are connected. A capacitor C75 is connected between the second pin and the third pin of the voltage reference chip U5.

4. The high-precision regulated output circuit of a switching power supply according to claim 3, wherein The operational amplifier module includes an operational amplifier U1. The third pin of the operational amplifier U1 is connected to a resistor R83. The second pin of the operational amplifier U1 is divided into two paths: one path is connected to the first pin of the common-mode inductor LF3 through a resistor R86, and the other path is grounded through a capacitor C76. The first pin of the operational amplifier U1 serves as the output terminal and is connected to the feedback module. A resistor R85 and a capacitor C74 are connected between the first pin and the second pin of the operational amplifier U1.

5. The high-precision regulated output circuit of a switching power supply according to claim 4, wherein The feedback module includes an optocoupler U3. The second pin of the optocoupler U3 is divided into two paths: one path is connected to the first pin of the operational amplifier U1 through diode D24, and the other path is connected to the voltage regulation control circuit. The first pin of the optocoupler U3 is divided into two paths: one path is connected to the second pin of the optocoupler U3 through resistor R60, and the other path is connected to the third pin of the common mode inductor LF3 through switching diode ZD4 and resistor R42.

6. The high-precision regulated output circuit of a switching power supply according to claim 5, wherein The voltage regulation control circuit includes a voltage reference chip U2. The second pin of the voltage reference chip U2 is connected to the second pin of the optocoupler U3. The third pin of the voltage reference chip U2 is grounded. The first pin of the voltage reference chip U2 is connected to the third pin of the common mode inductor LF3 through resistors R69, R66, and R67. A second filter circuit consisting of capacitors C72 and C48 and resistor R62 is connected between the first and second pins of the voltage reference chip U2. Resistors R65 and R64 are connected in parallel between the first and third pins of the voltage reference chip U2.

Images