A bipolar high-power linear voltage regulator circuit

Abstract

The utility model discloses a bipolar high -power linear voltage regulator power supply circuit. The utility model discloses the power transformer in it, has two independent, isolated and the same number of turns secondary winding, is used for providing positive and negative two way ac voltage respectively, first rectifier bridge and second rectifier bridge are connected respectively two secondary winding, are used for converting ac voltage into pulsating direct current voltage, first high -power linear voltage regulator module and second high -power linear voltage regulator module are used for linear voltage regulator processing to pulsating direct current voltage, the reference end of first high -power linear voltage regulator module is connected with the output of second high -power linear voltage regulator module, forms common ground terminal, thereby constitutes symmetrical bipolar output structure. The utility model disperses most power consumption on the external power tube, and adopts multistage filter, effectively solved the heat dissipation and power frequency ripple suppression problem under the high -power application of traditional linear power supply, realized low noise, high stability bipolar high -power output.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, specifically a bipolar high-power linear regulated power supply circuit. Background Technology

[0002] Bipolar regulated power supplies (i.e., power supplies capable of simultaneously providing positive and negative output voltages) play an irreplaceable role in scientific research experiments, industrial testing, and high-precision electronic equipment. They are commonly used to power loads such as operational amplifiers, data converters, sensor analog front-ends, and laboratory instruments. These power supplies not only need to achieve a continuous and smooth transition between positive and negative outputs, but also must possess core characteristics such as low noise and high stability to meet the stringent requirements of various sensitive circuits.

[0003] Current mainstream technologies primarily encompass two architectures: linear regulation and switching regulation. Linear regulated power supplies, with their advantages of low output ripple and low conducted noise, are preferred in applications requiring high power purity. However, as power levels increase to higher power ranges, traditional integrated linear regulator chips struggle to effectively address the resulting efficiency and heat dissipation challenges. Furthermore, suppressing power frequency ripple typically relies on numerous large-capacity capacitors, which not only increases the overall size but also presents practical difficulties for achieving compact and highly reliable power system designs.

[0004] Therefore, there is an urgent need in this field to solve the design problem of high-power bipolar linear regulated power supplies in order to achieve bipolar high-power linear regulated output with both high efficiency and high reliability. Utility Model Content

[0005] This invention proposes a bipolar high-power linear regulated power supply circuit, which achieves bipolar high-power linear regulated output with both high efficiency and compact size.

[0006] This utility model includes: a power frequency transformer, two identical rectifier bridges, and two identical high-power linear voltage regulator modules.

[0007] A power frequency transformer has two independent, isolated secondary windings with the same number of turns, used to provide positive and negative AC voltages respectively;

[0008] The first rectifier bridge and the second rectifier bridge are respectively connected to the two secondary windings and are used to convert AC voltage into pulsating DC voltage.

[0009] The first high-power linear regulator module and the second high-power linear regulator module are respectively connected to the DC output terminals of the first rectifier bridge and the second rectifier bridge, and are used to perform linear regulation of pulsating DC voltage.

[0010] In this configuration, the output terminal of the first high-power linear regulator module serves as the positive voltage output terminal, and the reference terminal of the second high-power linear regulator module serves as the negative voltage output terminal. Furthermore, the reference terminal of the first high-power linear regulator module and the output terminal of the second high-power linear regulator module are connected to form a common ground terminal, thereby constituting a symmetrical bipolar output structure.

[0011] Furthermore, the two secondary windings of the power frequency transformer are in a double-wire parallel winding configuration.

[0012] Furthermore, the first high-power linear regulator module and the second high-power linear regulator module have the same circuit structure, and along the signal flow direction, they sequentially include: a first-stage input filter circuit, a second-stage input filter circuit, a voltage regulator circuit, a power amplifier circuit, and an output filter circuit.

[0013] Furthermore, the first-stage input filter circuit consists of multiple electrolytic capacitors connected in parallel, with a withstand voltage value higher than 1.2 times the open-circuit voltage after rectification, and is used to absorb low-frequency ripple.

[0014] Furthermore, the second-stage input filter circuit includes a high-power NPN transistor and an RC network. The transistor amplification is used to amplify the current of the base filter signal, thereby reducing the amount of capacitor used and enhancing the ripple suppression effect.

[0015] Furthermore, the voltage regulator circuit uses an LDO chip and sets the output reference voltage through external voltage divider resistors R5 and R6. Schottky diodes are connected in parallel at the input and output terminals to prevent reverse breakdown.

[0016] Furthermore, the power amplifier circuit adopts a Darlington complementary push-pull structure, consisting of a high-power PNP transistor and a high-power NPN transistor, and is used to amplify the output of the voltage regulator circuit with a large current.

[0017] Furthermore, the output filter circuit has a capacitor C8 connected in parallel between the output terminal and the reference terminal of the power amplifier circuit to further filter out high-frequency noise and improve the purity of the output DC.

[0018] Furthermore, all power transistors are mounted on heatsinks that match power consumption to ensure that junction temperatures do not exceed maximum ratings and guarantee long-term reliability.

[0019] Furthermore, the power supply output is a bipolar voltage with positive and negative polarities, and the positive and negative outputs are symmetrical through a common ground terminal, making it suitable for powering operational amplifiers, data converters, and high-precision instruments.

[0020] This invention effectively solves the heat dissipation and power frequency ripple suppression problems of traditional linear power supplies in high-power applications by distributing most of the power consumption to external power transistors such as Q1, Q2, and Q3 and using multi-stage filtering, thus achieving low-noise, high-stability bipolar high-power output. Attached Figure Description

[0021] Figure 1 Schematic diagram of a bipolar high-power linear regulated power supply circuit;

[0022] Figure 2 Schematic diagram of a high-power linear voltage regulator module. Detailed Implementation

[0023] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings. It should be understood that the following description is merely illustrative and does not constitute a limitation on the scope of protection of this invention.

[0024] The core of the "bipolar high-power linear regulated power supply circuit" provided in this application is that a symmetrical positive and negative output power supply system with consistent performance is constructed through a transformer and two sets of completely symmetrical high-power linear regulated modules. Innovatively, the reference ground potential of one module is connected to the output of the other module to form a ground terminal, which simplifies the system structure and ensures the symmetry of the output.

[0025] The bipolar high-power linear regulated power supply circuit mainly includes: a power frequency transformer, a first rectifier bridge, a second rectifier bridge, a first high-power linear regulator module, and a second high-power linear regulator module.

[0026] The power frequency transformer has one input winding and two isolated output windings with the same number of turns. The two output windings of the power frequency transformer are respectively connected to the input terminals of two rectifier bridges.

[0027] Each of the output terminals of the rectifier bridges is connected to a high-power linear regulator module, i.e., the first rectifier bridge corresponds to the first high-power linear regulator module and the second rectifier bridge corresponds to the second high-power linear regulator module.

[0028] The reference terminal of the first high-power linear regulator module in the two identical high-power linear regulator modules is connected to the output terminal of the second high-power linear regulator module as the ground terminal of the bipolar power supply.

[0029] In this embodiment, a common specification of 5A output current and ±20V output voltage is used. The primary winding (input winding) of the power frequency transformer is connected to the mains power. The secondary winding of the transformer has two independent, isolated windings with the same number of turns, referred to as the first output winding and the second output winding, respectively. The rated voltage of the two secondary output windings is configured as ±35VAC. The first output winding is connected to the AC input terminal of the first rectifier bridge, and the second output winding is connected to the AC input terminal of the second rectifier bridge. To withstand the inrush current and provide sufficient current margin, its rated rectified current should not be less than 10A.

[0030] The positive (+) and negative (-) DC output terminals of the first rectifier bridge are connected to the In1+ and Com1 terminals of the first linear regulator module, respectively. Similarly, the positive (+) and negative (-) DC output terminals of the second rectifier bridge are connected to the In2+ and Com2 terminals of the second linear regulator module, respectively.

[0031] The output terminal Vout1 of the first high-power linear regulator module serves as the positive voltage output terminal (V+) of the entire power supply. The reference terminal Com2 of the second high-power linear regulator module serves as the negative voltage output terminal (V-) of the entire power supply. The reference terminal Com1 of the first linear regulator module (i.e., its internal common ground potential) is connected to the output terminal Vout2 of the second linear regulator module. This connection point is the common ground terminal (GND) of the entire bipolar power supply.

[0032] Furthermore, the high-power linear regulator module includes a first-stage input filter circuit, a second-stage input filter circuit, a voltage regulator circuit, a power amplifier circuit, and an output filter circuit.

[0033] The first-stage input filter circuit includes a set of capacitors connected in parallel across the input terminals; it is then connected to the second-stage input filter circuit.

[0034] The second-stage filter circuit consists of a first transistor and a set of RC filters. The collector and emitter of the first transistor are the input and output of the second-stage filter circuit, respectively. The RC filters consist of a first resistor and a set of capacitors, with the input of the RC filters connected to the collector of the first transistor and the output of the RC filters connected to the base of the first transistor. The emitter of the second-stage filter circuit is connected to the input of the voltage regulator circuit.

[0035] The voltage regulator circuit includes a second resistor, an LDO voltage regulator chip, a fifth resistor, and a sixth resistor. The second resistor is connected in series between the emitter of the second-stage filter circuit and the input terminal of the LDO voltage regulator chip. The ADJ pin of the LDO voltage regulator chip is connected to the midpoint of the voltage divider formed by the fifth and sixth resistors connected in series. The fifth and sixth resistors are connected to the output terminal of the LDO voltage regulator chip and the reference terminal of the circuit, respectively.

[0036] The output terminal of the voltage regulator circuit is connected to a power amplifier circuit consisting of a second transistor, a third transistor, a third resistor, and a fourth resistor.

[0037] The output stage filter circuit is connected in parallel between the output terminal and the reference terminal of the power amplifier circuit.

[0038] The reference terminal of the first high-power linear regulator module in the two identical high-power linear regulator modules is connected to the output terminal of the second high-power linear regulator module as the ground terminal of the bipolar power supply.

[0039] by Figure 2 Taking the first high-power linear regulator module as an example, its internal circuit structure will be explained in detail. The second linear regulator module is exactly the same.

[0040] The high-power linear voltage regulator module includes, in sequence along the signal flow direction: a first-stage input filter circuit, a second-stage input filter circuit, a voltage regulator circuit, a power amplifier circuit, and an output filter circuit.

[0041] The first-stage input filter circuit consists of electrolytic capacitors C1 to C3 connected in parallel, directly across the output terminals of the rectifier bridge (between In1+ and Com1). It performs preliminary filtering of the pulsating DC after rectification, absorbing large-amplitude low-frequency ripple. The capacitance of electrolytic capacitors C1 to C3 ranges from 2200μF to 10000μF, and their voltage rating should be at least 1.2 times higher than the open-circuit voltage after rectification; here, 50V is selected.

[0042] The second-stage input filter circuit, connected in series after the first-stage filter circuit, consists of a high-power NPN transistor Q1 and an RC filter network. In this example, Q1 is selected as a high-power NPN transistor 2N3055, with a maximum continuous collector current IC ≥ 5A. The collector of Q1 is connected to the previous stage In1+, and the emitter serves as the output of this stage. The RC filter consists of a resistor R1 and parallel capacitors C4~C6, where R1 is 100Ω, and C4~C6 are electrolytic capacitors of the same specification as C1~C3. The series connection point of R1 and the capacitor bank is connected to the base of Q1.

[0043] Preferably, a discharge resistor R7 with a value of 10kΩ is connected in parallel across capacitor C3. Its function is to provide a discharge circuit for the capacitor when the power is off, thereby enhancing safety.

[0044] The second-stage input filter circuit actually filters the base signal of transistor Q1. By leveraging the amplification effect of the transistor, the filtering effect is amplified, thereby significantly reducing the number of capacitors required.

[0045] The input of the voltage regulator circuit is connected to the emitter of Q1. This circuit includes a current-limiting resistor R2, an LDO regulator chip U1 (LM317 in this example), and a voltage divider consisting of resistors R5 and R6. Resistor R2 is connected in series between the emitter of Q1 and the input of U1. The adjustment terminal (ADJ) of U1 is connected to the midpoint of the series connection of R5 and R6. The other end of R5 is connected to the output terminal (OUT) of U1, and the other end of R6 is connected to the module's reference terminal Com1. By adjusting the resistance ratio of R5 and R6, the reference voltage of the U1 output can be set. To prevent reverse breakdown, a Schottky diode D1 is connected in parallel between the input and output terminals of U1. This diode is selected as 1N5822, with a rated reverse operating voltage higher than 30V.

[0046] Power amplifier circuit: Employs a Darlington transistor structure to provide high current drive capability. It consists of a high-power PNP transistor Q2, a high-power NPN transistor Q3, and base resistors R3 and R4. It uses a Darlington transistor complementary push-pull amplification configuration to amplify the regulated signal output from U1. Specifically, Q2 is a high-power PNP transistor MJ2955, and Q3 is a high-power transistor 2N3055.

[0047] Output filter circuit: Capacitor C8 is connected between the output terminal (out1) and the reference terminal Com1 of the power amplifier circuit to further filter out high-frequency noise and ensure the high purity of the output DC.

[0048] In this circuit, all power components (such as Q1, Q2, Q3, etc.) must be mounted on heat sinks that match their power consumption to ensure that the junction temperature does not exceed its maximum rated value, thus guaranteeing the long-term reliability of the system. Since the circuit parameters of the two modules are completely identical, the connection between Com1 and out2 forms a ground potential, thereby creating a symmetrical bipolar output.

[0049] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A bipolar high-power linear regulated power supply circuit, characterized in that, include: Power frequency transformer, two identical rectifier bridges, and two identical high-power linear voltage regulator modules; A power frequency transformer has two independent, isolated secondary windings with the same number of turns, used to provide positive and negative AC voltages respectively; The first rectifier bridge and the second rectifier bridge are respectively connected to the two secondary windings and are used to convert AC voltage into pulsating DC voltage. The first high-power linear regulator module and the second high-power linear regulator module are respectively connected to the DC output terminals of the first rectifier bridge and the second rectifier bridge, and are used to perform linear regulation of pulsating DC voltage. In this configuration, the output terminal of the first high-power linear regulator module serves as the positive voltage output terminal, and the reference terminal of the second high-power linear regulator module serves as the negative voltage output terminal. Furthermore, the reference terminal of the first high-power linear regulator module and the output terminal of the second high-power linear regulator module are connected to form a common ground terminal, thereby constituting a symmetrical bipolar output structure.

2. The bipolar high-power linear regulated power supply circuit according to claim 1, characterized in that, The two secondary windings of the power frequency transformer are wound in a double-wire parallel configuration.

3. The bipolar high-power linear regulated power supply circuit according to claim 1, characterized in that, The first high-power linear regulator module and the second high-power linear regulator module have the same circuit structure, and along the signal flow direction, they include: a first-stage input filter circuit, a second-stage input filter circuit, a voltage regulator circuit, a power amplifier circuit, and an output filter circuit.

4. The bipolar high-power linear regulated power supply circuit according to claim 3, characterized in that, The first-stage input filter circuit consists of multiple electrolytic capacitors connected in parallel, with a withstand voltage value higher than 1.2 times the open-circuit voltage after rectification, and is used to absorb low-frequency ripple.

5. A bipolar high-power linear regulated power supply circuit according to claim 3, characterized in that, The second-stage input filter circuit includes a high-power NPN transistor and an RC network. It uses the transistor's amplification effect to amplify the current of the base filter signal, thereby reducing the amount of capacitor used and enhancing the ripple suppression effect.

6. A bipolar high-power linear regulated power supply circuit according to claim 3, characterized in that, The voltage regulator circuit uses an LDO chip and sets the output reference voltage through external voltage divider resistors R5 and R6. Schottky diodes are connected in parallel at the input and output terminals to prevent reverse breakdown.

7. A bipolar high-power linear regulated power supply circuit according to claim 3, characterized in that, The power amplifier circuit adopts a Darlington complementary push-pull structure, consisting of a high-power PNP transistor and a high-power NPN transistor, and is used to amplify the high current output of the voltage regulator circuit.

8. A bipolar high-power linear regulated power supply circuit according to claim 3, characterized in that, The output filter circuit has a capacitor C8 connected in parallel between the output terminal and the reference terminal of the power amplifier circuit to further filter out high-frequency noise and improve the purity of the output DC.

9. A bipolar high-power linear regulated power supply circuit according to any one of claims 4 to 8, characterized in that, All power transistors are mounted on heatsinks that match power consumption to ensure that junction temperatures do not exceed maximum ratings and guarantee long-term reliability.

10. A bipolar high-power linear regulated power supply circuit according to claim 9, characterized in that, The power supply output is a bipolar voltage with positive and negative polarities, and the positive and negative outputs are symmetrical through a common ground terminal, making it suitable for powering operational amplifiers, data converters, and high-precision instruments.

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