CN210123940U - Constant voltage source - Google Patents

Abstract

The utility model discloses a constant voltage source, which comprises a device power supply, a first push-pull module and a second push-pull module, wherein the first end of the first push-pull module is connected with a first voltage, the second end is connected with the first input end of the device power supply, and the third end is connected with the output end of the device power supply; a first end of the second push-pull module is connected with a second voltage, a second end of the second push-pull module is connected with a second input end of the device power supply, and a third end of the second push-pull module is connected with an output end of the device power supply; the device power supply outputs a stable voltage according to a first voltage input by the first push-pull module and a second voltage input by the second push-pull module. The utility model provides an embodiment utilizes device power, first push-pull module and second push-pull module can simplify the structure of constant voltage source among the prior art, accelerate development cycle and reduce cost.

Description

Constant voltage source

Technical Field

The utility model relates to a power technical field especially relates to a constant voltage source.

Background

At present, the constant voltage source mainly has the following schemes: 1) switching power supply type: the special PWM (pulse width modulation) chip or PFM (pulse frequency modulation) plus high-frequency isolation transformer and rectification filter circuit are used to form forward, self-excitation, push-pull type, etc. to realize the voltage boosting, voltage reduction and turnover output, mainly applied to the occasion with high power and low ripple requirement; 2) DC-DC switching regulator type: the device is simple to apply, can select a switching power supply loop formed by internally integrating or externally matching passive components such as FETs (field effect transistors), inductors and the like according to specific application, and is mainly applied to occasions with low requirements on medium and small power and ripple waves. 3) A voltage stabilizing source composed of low dropout regulator (LDO) core devices is mainly applied to occasions with high requirements on low power and noise. 4) And a linear constant voltage source consisting of an operational amplifier and a FET or a BJT: due to the fact that an external power device is used, power is greatly improved compared with scheme 3, driving power can reach more than 500mA, and the power-driven high-power-factor LED driving circuit is mainly applied to occasions where the voltage range is not wide and large heat dissipation environments can be provided.

SUMMERY OF THE UTILITY MODEL

In order to solve at least one of the above problems, the present invention provides a constant voltage source, which comprises a device power supply, a first push-pull module and a second push-pull module, wherein

A first end of the first push-pull module is connected with a first voltage, a second end of the first push-pull module is connected with a first input end of the device power supply, and a third end of the first push-pull module is connected with an output end of the device power supply;

a first end of the second push-pull module is connected with a second voltage, a second end of the second push-pull module is connected with a second input end of the device power supply, and a third end of the second push-pull module is connected with an output end of the device power supply;

the device power supply outputs a stable voltage according to a first voltage input by the first push-pull module and a second voltage input by the second push-pull module.

Further, in the above-mentioned case,

the first push-pull module comprises a first triode and a first bias resistor, an emitter of the first triode and one end of the first bias resistor are connected to serve as a first end of the first push-pull module, a base of the first triode and the other end of the first bias resistor are connected to serve as a second end of the first push-pull module, and a collector of the first triode serves as a third end of the first push-pull module;

the second push-pull module comprises a second triode and a second bias resistor, an emitter of the second triode and one end of the second bias resistor are connected to serve as a first end of the second push-pull module, a base of the second triode and the other end of the second bias resistor are connected to serve as a second end of the second push-pull module, and a collector of the second triode serves as a third end of the second push-pull module;

the polarity of the first triode and the polarity of the second triode are opposite.

Further, the first triode and the second triode are respectively bipolar transistors.

Further, the constant voltage source further includes a feedback unit configured to feed back a load terminal voltage output by the device power supply to a feedback input terminal of the device power supply.

Further, the feedback unit includes a first feedback module and a second feedback module, and the first feedback module and the second feedback module respectively include a low-pass filter circuit.

Further, in the above-mentioned case,

the first push-pull module further comprises a first current-limiting resistor for protecting the first triode;

the second push-pull module further comprises a second current-limiting resistor for protecting the second triode.

The utility model has the advantages as follows:

the utility model discloses to present problem, formulate a constant voltage source, through device power, first push-pull module and second push-pull module output steady voltage, effectively simplify the structure of constant voltage source among the prior art, accelerate development cycle and reduce cost.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Fig. 1 shows a circuit diagram of a constant voltage source according to an embodiment of the present invention.

Detailed Description

In order to explain the present invention more clearly, the present invention will be further described with reference to the preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

The inventor finds that the four common constant voltage source solutions in the prior art all have the following disadvantages: 1) for the switching type voltage source, due to the self working principle, the ripple current generates larger ripple voltage when passing through a filter circuit such as a capacitor, and the application of the ripple current in a precise detection circuit is influenced, and due to the existence of the Vfb voltage, the output range of the switching type voltage source cannot realize the coverage between 0V and Vfb and only can be higher than the output of the Vfb. 2) For a linear voltage-stabilizing source, due to linear voltage reduction, an LDO device or an external triode device needs to bear larger power loss, and due to the limitation of feedback bandwidth and the limitation of response speed, the far-end induction compensation adjustment cannot be realized, namely, a feedback line (FB) cannot be too long when the device is arranged on a circuit board; and due to the existence of Vfb voltage, the output range of the Vfb voltage cannot realize the coverage between 0V and Vfb, the output range of the Vfb voltage is only higher than the Vfb output and the voltage at 0 point, the output offset is difficult to eliminate, and the like.

In order to solve at least one of the above problems, the inventor has made research and numerous experiments, and has proposed a constant voltage source, as shown in fig. 1, including a device power supply, a first push-pull module and a second push-pull module, wherein a first end of the first push-pull module is connected to a first voltage, a second end of the first push-pull module is connected to a first input end of the device power supply, and a third end of the first push-pull module is connected to an output end of the device power supply; and the first end of the second push-pull module is connected with a second voltage, the second end of the second push-pull module is connected with the second input end of the device power supply, and the third end of the second push-pull module is connected with the output end of the device power supply. The constant voltage source is different from the constant voltage source in the prior art, and the constant voltage source can effectively improve the performance of the traditional constant voltage source by adopting the device power supply, realizes positive and negative adjustability without crossing dead zones, and simultaneously can simplify the circuit structure and reduce the cost.

Specifically, as shown in fig. 1, the constant voltage source includes adevice power supply 10, a first push-pull module 20, and a second push-pull module 20'. The Device Power Supply 10 is a DPS (Programmable Device Power Supply) chip, and the Device Power Supply 10 is internally provided with an operational amplifier, a comparator circuit, a digital-to-analog converter, and the like, and can provide Programmable driving voltage, current, and voltage sampling value analog quantity output, and in this embodiment, theDevice Power Supply 10 is an AD 5560.

The first push-pull module 20 includes a first transistor Q1 and a first bias resistor R1, an emitter of the first transistor Q1 and one end of the first bias resistor R1 are connected as a first end 1 of the first push-pull module 20, and are connected to a first voltage VCC, a base of the first transistor Q1 and the other end of the first bias resistor R1 are connected as asecond end 2 of the first push-pull module 20, and are connected to afirst input end 11 of thedevice power supply 10, and a collector of the first transistor Q1 is connected to anoutput end 13 of thedevice power supply 10 as a third end 3 of the first push-pull module 20. The second push-pull module 20 'includes a second transistor Q2 and a second bias resistor R2, an emitter of the second transistor Q2 and one end of the second bias resistor R2 are connected as a first end 1 of the second push-pull module 20' and are connected to a second voltage VSS, a base of the second transistor Q2 and the other end of the second bias resistor R2 are connected as asecond end 2 of the second push-pull module 20 'and are connected to thesecond input end 12 of thedevice power supply 10, and a collector of the second transistor Q2 is connected to theoutput end 13 of thedevice power supply 10 as a third end 3 of the second push-pull module 20'. The first triode and the second triode are opposite in polarity and connected in a push-pull mode, and in the embodiment, the first triode and the second triode are respectively bipolar transistors.

In an optional embodiment, the constant voltage source further includes a feedback unit for feeding back a load terminal voltage output by the device power supply to a feedback input terminal of the device power supply.

Specifically, as shown in fig. 1, the stable voltage output by thedevice power supply 10 is loaded on theload 30 to be measured, and thefeedback unit 40 includes a first feedback module and a second feedback module, where the first feedback module and the second feedback module respectively include a low-pass filter circuit. The first feedback module leads out the voltage of oneend 31 of theload 30 to be tested, the voltage is filtered by a resistor R5 and a capacitor C2 of a low-pass filter circuit and fed back to thefeedback input end 14 of thedevice power supply 10, the voltage of theother end 32 of theload 30 to be tested is led out by the second feedback module, the voltage is filtered by a resistor R6 and a capacitor C3 of the low-pass filter circuit and fed back to thefeedback input end 15 of thedevice power supply 10, namely, the load end voltage output by the device power supply is fed back to the feedback input end of the device power supply, and the capacitor C1 is bridged on the first feedback module and the second feedback module to eliminate the common mode noise of thedevice power supply 10 and reduce the power supply noise output by thedevice power supply 10 and the noise of analog quantity.

In another alternative embodiment, as shown in fig. 1, the first push-pull module further includes a first current limiting resistor R3 for protecting the first transistor Q1; the second push-pull module further comprises a second current limiting resistor R4 for protecting the second transistor Q2.

In this embodiment, the first current-limiting resistor R3 and the second current-limiting resistor R4 are resistors with the same resistance, so that device damage and load damage caused by over-saturation conduction of the transistors due to excessive base currents of the first transistor and the second transistor can be avoided.

In a specific example, when the first terminal 1 of the first push-pull module is connected to the first voltage VCC while the second terminal of the first push-pull module is connected to the device power input terminal, a bias voltage is formed between the base and the emitter of the first transistor Q1 by a current flowing through the first bias resistor R1, the first transistor Q1 is turned on, and in this embodiment, the first transistor Q1 is protected by the first current limiting resistor R3. Similarly, the second push-pull module turns on the second transistor Q2 by current flowing through the second bias resistor R2, and protects the second transistor Q2 through the second current limiting resistor R4.

It should be noted that, when the current required by the load to be tested is larger, the required bias voltage is also larger, and the base currents flowing into the first triode Q1 and the second triode Q2 are larger, the output current Ic of the first triode Q1 and the second triode Q2 is also larger, so as to ensure the stability of the output voltage. Meanwhile, in the present embodiment, thedevice power supply 10 further adjusts the output voltage through a feedback unit.

This example is only for better understanding the technical solution of the embodiment of the present invention, and is not intended to be the only limitation to the embodiment of the present invention, and those skilled in the art should set the bias resistor and the current limiting resistor according to the actual application scenario to meet the application requirement, and will not be described herein again.

The constant voltage source provided by this embodiment uses thedevice power supply 10 as a core device, and has the following characteristics while outputting a stable voltage:

1) the circuit structure is effectively simplified, for example, an analog-digital conversion circuit, a pole compensation circuit, a feedback bandwidth setting circuit, a sampling measurement preprocessing circuit, an overvoltage protection circuit, a temperature measurement circuit and the like are not required to be arranged independently.

2) The cost is effectively reduced, the volume of the constant voltage source can be reduced and the power density is improved because a complex peripheral circuit is not needed, and compared with the constant voltage source with a complex signal chain circuit in the prior art, the device cost is greatly reduced.

3) The development cycle is effectively accelerated, and the device power supply of the integrated circuit is used, so that the peripheral device model selection time and the development and debugging time can be saved.

4) The maintenance efficiency is effectively improved, and later-stage production and maintenance can be simplified by using the device power supply, so that the manual maintenance efficiency is improved.

Therefore, the constant voltage source provided by the embodiment has wide application prospect.

The utility model discloses to present problem, formulate a constant voltage source, through device power, first push-pull module and second push-pull module output steady voltage, effectively simplify the structure of constant voltage source among the prior art, accelerate development cycle and reduce cost.

Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it is obvious for those skilled in the art to make other variations or changes based on the above descriptions, and all the embodiments cannot be exhausted here, and all the obvious variations or changes that belong to the technical solutions of the present invention are still in the protection scope of the present invention.

Claims (6)

1. The constant voltage source is characterized by comprising a device power supply, a first push-pull module and a second push-pull module, wherein the first push-pull module and the second push-pull module are connected with each other through a first switch

A first end of the first push-pull module is connected with a first voltage, a second end of the first push-pull module is connected with a first input end of the device power supply, and a third end of the first push-pull module is connected with an output end of the device power supply;

a first end of the second push-pull module is connected with a second voltage, a second end of the second push-pull module is connected with a second input end of the device power supply, and a third end of the second push-pull module is connected with an output end of the device power supply;

the device power supply outputs a stable voltage according to a first voltage input by the first push-pull module and a second voltage input by the second push-pull module.

2. The constant voltage source of claim 1,

the first push-pull module comprises a first triode and a first bias resistor, an emitter of the first triode and one end of the first bias resistor are connected to serve as a first end of the first push-pull module, a base of the first triode and the other end of the first bias resistor are connected to serve as a second end of the first push-pull module, and a collector of the first triode serves as a third end of the first push-pull module;

the second push-pull module comprises a second triode and a second bias resistor, an emitter of the second triode and one end of the second bias resistor are connected to serve as a first end of the second push-pull module, a base of the second triode and the other end of the second bias resistor are connected to serve as a second end of the second push-pull module, and a collector of the second triode serves as a third end of the second push-pull module;

the polarity of the first triode and the polarity of the second triode are opposite.

3. The constant voltage source of claim 2, wherein the first transistor and the second transistor are bipolar transistors.

4. The constant voltage source of claim 1, further comprising a feedback unit for feeding back a load terminal voltage of the device power supply output to a feedback input of the device power supply.

5. The constant voltage source according to claim 4, wherein the feedback unit comprises a first feedback module and a second feedback module, each of the first feedback module and the second feedback module comprising a low pass filter circuit.

6. The constant voltage source according to claim 2 or 3,

the first push-pull module further comprises a first current-limiting resistor for protecting the first triode;

the second push-pull module further comprises a second current-limiting resistor for protecting the second triode.

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