WO2022077273A1

WO2022077273A1 - Direct current voltage output circuit, and method

Info

Publication number: WO2022077273A1
Application number: PCT/CN2020/120913
Authority: WO
Inventors: 李祥; 赵德琦; 吴壬华
Original assignee: 深圳欣锐科技股份有限公司
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2022-04-21
Also published as: CN113597733A

Abstract

Provided in the present application are a direct current output circuit and a method. The direct current output circuit comprises: an input power source end, a controller, a power conversion circuit, a rectifying and filtering circuit, a voltage sampling circuit, and an output power source end, wherein the voltage sampling circuit performs attenuation on voltages in different intervals among a wide range of output voltages according to different ratios and by means of a plurality of voltage dividing sampling modules, which ensures that a sampling voltage amplitude satisfies a sampling precision requirement of the controller, and the controller controls a voltage amplitude output of the power conversion circuit according to a sampling voltage fed back by the voltage sampling circuit, and thereby the precision of the controller in controlling an output voltage is increased, and consequently the precision and accuracy of the output voltage is increased.

Description

DC voltage output circuit and method

technical field

The present application relates to the field of electronic technology, and in particular, to a DC voltage output circuit and method.

Background technique

A switching power supply is a high-frequency power conversion device whose function is to convert an input voltage into the voltage or current required by the user through different forms of architecture. In the application scenario where the switching power supply outputs DC voltage, the controller of the switching power supply samples the output voltage, compares the sampled voltage with the reference voltage and obtains an error value, and then adjusts the output voltage or current according to the error value, thereby achieve the purpose of stable output.

However, in the application scenario where the switching power supply outputs a wide range of voltage, for example, the output voltage of the switching power supply is 0-1000V, since the power supply of the controller in the switching power supply is usually 3.3V, and the sampling voltage is generally controlled below 3V, the controller needs to pass the sampling circuit. The output voltage is attenuated proportionally before sampling. For example, the output voltage of 0-1000V is attenuated to 0-3V. Attenuating the output voltage of a wide range will cause the sampling voltage value of the low-voltage section of the output voltage to be small. Due to the sampling voltage The amplitude is too small to meet the sampling accuracy requirements of the controller, resulting in poor control accuracy of the output voltage by the controller and low accuracy of the output voltage.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems in the DC voltage output circuit, the present application provides a DC voltage output circuit and method, so that the DC voltage output circuit passes through a plurality of voltage division sampling modules, and the voltage in different intervals in the wide range of voltages is divided into different proportions. Attenuation is performed to ensure that the sampling voltage amplitude meets the sampling accuracy requirements of the controller, and the controller's control accuracy of the output voltage is improved, thereby improving the accuracy of the output voltage.

In a first aspect of the embodiments of the present application, a DC voltage output circuit is provided. The DC voltage output circuit is applied to a switching power supply, and includes an input power supply terminal, a controller, a power conversion circuit, a rectification filter circuit, a voltage sampling circuit, and an output power supply end;

The voltage sampling circuit includes N voltage division sampling modules, each of the voltage division sampling modules corresponds to a voltage sampling interval, and the voltage sampling intervals corresponding to any two of the voltage division sampling modules have no intersection; the first voltage division sampling module It includes a first input end and a first output end; the first voltage division sampling module is used to sample the DC voltage output by the rectification filter circuit; the first voltage division sampling module is the N voltage division sampling modules any of the modules;

The input power supply terminal is connected to the first terminal of the power conversion circuit; the controller is connected to the second terminal of the power conversion circuit; the third terminal of the power conversion circuit is connected to the first terminal of the rectifier and filter circuit ; the fourth end of the power conversion circuit is connected to the second end of the rectifier filter circuit; the third end of the rectifier filter circuit is connected to a plurality of input ends of the voltage sampling circuit and the output power supply end; the a plurality of output terminals of the voltage sampling circuit are connected to the controller;

The controller is used for obtaining the final sampling voltage of the voltage sampling circuit according to the corresponding relationship between the voltage dividing sampling module and the voltage amplification ratio; and for adjusting the final sampling voltage according to the relationship between the final sampling voltage and the reference voltage the voltage amplitude of the power conversion circuit, and for controlling the power conversion circuit to reduce the output voltage amplitude when the final sampled voltage is greater than the reference voltage; and for when the final sampled voltage is less than the reference voltage , controlling the power conversion circuit to increase the output voltage amplitude.

In one embodiment, the first voltage division sampling module includes a first upper bias resistor sub-module and a first lower bias resistor sub-module;

The third end of the rectifier and filter circuit is connected to the first end of the first upper bias resistor sub-module; the second end of the first upper bias resistor sub-module is connected to the first end of the first lower bias resistor sub-module The terminal is connected to the controller; the second terminal of the first lower bias resistor sub-module is grounded.

In one embodiment, the first upper bias resistor sub-module includes at least one resistor; the first lower bias resistor sub-module includes at least one resistor.

In an embodiment, in the first voltage division sampling module, the ratio of the resistance value of the first resistance sub-module to the resistance value of the first lower bias resistance sub-module is a first resistance value ratio, and the first resistance value ratio is The resistance value of a resistor sub-module is the sum of the resistance value of the first upper bias resistor sub-module and the resistance value of the first lower bias resistor sub-module; the first resistance ratio is the first divided voltage The voltage amplification ratio corresponding to the sampling module; the voltage amplification ratios corresponding to any two of the N voltage division sampling modules are different.

In one embodiment, the power conversion circuit includes a transformer and a switch;

The transformer includes a primary winding and a secondary winding; the input power end is connected to the first end of the primary winding; the controller is connected to the first end of the switch tube; the second end of the switch tube is connected to the the second end of the primary winding; the third end of the switch tube is grounded; the first end of the secondary winding is connected to the first end of the rectifier and filter circuit; the second end of the secondary winding is connected to the the second end of the rectifier filter circuit;

The controller adjusts the voltage amplitude of the output power supply terminal by outputting a pulse width modulation signal to the second end of the switch tube and adjusting the duty cycle of the pulse width modulation signal.

In one embodiment, the switch tube includes any one of a relay, a triode or a MOS tube.

In one embodiment, the rectification filter circuit includes a diode and a capacitor;

The third end of the power conversion circuit is connected to the anode of the diode; the cathode of the diode is connected to the first end of the capacitor, a plurality of input ends of the voltage sampling circuit and the output power supply end; The second end is connected to the fourth end of the power conversion circuit and the ground.

In one embodiment, the capacitor includes a polar capacitor; a first end of the polar capacitor is a positive electrode, and a second end of the polar capacitor is a negative electrode.

In one embodiment, among the N voltage division sampling modules, the larger the midpoint value of the voltage sampling interval corresponding to the voltage division sampling module, the larger the corresponding voltage amplification ratio.

In a second aspect of the embodiments of the present application, a direct current voltage output method is provided, which is applied to the above-mentioned direct current voltage output circuit, and the method includes:

The controller determines a target voltage sampling interval in which the output voltage of the DC voltage output circuit falls and a target voltage division sampling module corresponding to the target voltage sampling interval;

obtaining, by the controller, a target sampling voltage sampled by the target voltage division sampling module, where the target sampling voltage is an initial sampling voltage of the voltage sampling circuit;

The controller determines a target amplification ratio corresponding to the target sampling voltage module according to the corresponding relationship between the voltage division sampling module and the voltage amplification ratio;

The controller amplifies the initial sampling voltage according to the target amplification ratio to obtain the final sampling voltage of the voltage sampling circuit;

The controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result.

In one embodiment, the controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result, including: when the final sampled voltage is greater than the reference voltage When the value is , the controller controls the power conversion circuit to reduce the output voltage amplitude; when the final sampled voltage is less than the reference voltage, the controller controls the power conversion circuit to increase the output voltage amplitude.

Implementing the embodiments of the present application, for a wide range of output voltages, the voltage sampling circuit attenuates the voltages in different intervals in the wide range of output voltages according to different proportions through a plurality of voltage division sampling modules, and adopts voltage segmentation sampling to ensure that each The sampling voltage amplitudes in the voltage range all meet the sampling accuracy requirements of the controller. The controller controls the voltage amplitude output of the power conversion circuit according to the sampling voltage fed back by the voltage sampling circuit, so as to improve the control accuracy of the output voltage by the controller, thereby making the output The accuracy of the voltage is improved.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

1 is a schematic structural diagram of a DC voltage output circuit in the prior art;

2 is a schematic structural diagram of a DC voltage output circuit in an embodiment of the present application;

3 is a schematic diagram of a specific structure of a DC voltage output circuit in an embodiment of the present application;

FIG. 4 is a flowchart of a method for outputting a DC voltage in an embodiment of the present application.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

The terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish different objects, rather than to describe a specific order. Furthermore, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes Other steps or units inherent in a process, product or equipment.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor a separate or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

1 is a schematic diagram of a DC voltage output circuit in the prior art. In the existing DC voltage output circuit applied to a switching power supply, when the voltage sampling circuit samples a wide-range output voltage, the output voltage of the low-voltage section usually does not meet the control requirements. Due to the sampling accuracy requirements of the device, the error between the sampling voltage of the low-voltage section and the actual output voltage is too large, and the required DC voltage cannot be output.

Please refer to FIG. 2 , which is a schematic structural diagram of a DC voltage output circuit according to an embodiment of the present application.

The present application provides a DC voltage output circuit 200, including an input power supply terminal Uin, a controller 240, a power conversion circuit 210, a rectification filter circuit 220, a voltage sampling circuit 230, and an output power supply terminal Uout.

The above-mentioned voltage sampling circuit 230 includes N voltage-dividing sampling modules, each voltage-dividing sampling module corresponds to a voltage sampling interval, the voltage sampling intervals corresponding to any two voltage-dividing sampling modules have no intersection, and the first voltage-dividing sampling module includes the first voltage sampling interval. An input end and a first output end, the first voltage division sampling module is used for sampling the DC voltage output by the rectification filter circuit, and the first voltage division sampling module is any one of the N voltage division sampling modules. N is an integer greater than or equal to 2.

The input power terminal Uin is connected to the first terminal 211 of the power conversion circuit 210 , the controller 240 is connected to the second terminal 212 of the power conversion circuit 210 , and the third terminal 213 of the power conversion circuit 210 is connected to the rectifier and filter circuit 220 . The first terminal 221, the fourth terminal 214 of the power conversion circuit 210 is connected to the second terminal 222 of the rectification filter circuit 220, the third terminal 223 of the rectification filter circuit 220 is connected to the multiple input terminals of the voltage sampling circuit 230 and the above The output power supply terminal Uout, a plurality of output terminals of the voltage sampling circuit 230 are connected to the controller 240 .

The above-mentioned controller 240 is used for obtaining the final sampling voltage of the above-mentioned voltage sampling circuit 230 according to the corresponding relationship between the above-mentioned voltage division sampling module and the voltage amplification ratio, and for adjusting the above-mentioned power conversion according to the relationship between the above-mentioned final sampling voltage and the reference voltage The voltage amplitude of the circuit 210, and for controlling the power conversion circuit 210 to reduce the output voltage amplitude when the final sampling voltage is greater than the reference voltage; and for controlling the power when the final sampling voltage is less than the reference voltage Conversion circuit 210 increases the voltage amplitude of the output.

Through the above connection method, the voltage sampling circuit attenuates the voltages in different sections of the wide-range output voltage according to different proportions through a plurality of voltage division sampling modules, and adopts voltage subsection sampling to ensure the sampling voltage amplitude in each voltage section. All meet the sampling accuracy requirements of the controller. The controller controls the voltage amplitude output of the power conversion circuit according to the sampling voltage fed back by the voltage sampling circuit, thereby improving the controller’s control accuracy of the output voltage, and thus making the output voltage of the switching power supply more accurate. improve.

Among them, the midpoint values of the voltages in different intervals are different, and the interval with a larger midpoint value has a larger attenuation ratio. The smaller the midpoint value is, the smaller the attenuation ratio is. The midpoint value is the average of the maximum and minimum values of the interval. For example, if the voltage interval is (100, 300), the corresponding midpoint value of the voltage interval is 200V.

In one embodiment, as shown in FIG. 3 , the above-mentioned voltage sampling circuit 230 includes N voltage division sampling modules, wherein the first voltage division sampling module 310 includes a first upper bias resistor sub-module 311 and a first lower bias resistor sub-module 311 Module 312 , the second voltage division sampling module 320 includes a second upper bias resistor sub-module 321 and a second lower bias resistor sub-module 322 . The first voltage division sampling module 310 and the second voltage division sampling module 320 are any two of the N voltage division sampling modules.

The third end 223 of the rectifier and filter circuit 220 is connected to the first end of the first upper bias resistor sub-module 311 and the first end of the second upper bias resistor sub-module 321 . The two terminals are connected to the first terminal of the first lower bias resistor sub-module 312 and the controller 240 . The second terminal of the first upper bias resistor sub-module 321 is connected to the first terminal of the second lower bias resistor sub-module 322 and the controller 240 is connected, the second end of the first lower bias resistor sub-module 312 and the second end of the second lower bias resistor sub-module 322 are grounded.

Optionally, the first upper bias resistor sub-module 311 includes at least one resistor, and the first lower bias resistor sub-module 312 includes at least one resistor. As shown in FIG. 3, in one embodiment, the first upper bias resistor sub-module 311 includes resistors R1 and R2, the first lower bias resistor sub-module includes a resistor R3, and the second upper bias resistor sub-module 321 includes a resistor R4, the second lower bias resistor sub-module 322 includes a resistor R5. In the above-mentioned first voltage dividing resistor sub-module 310, the number of resistors included in the first upward biasing resistor sub-module 310 is determined by the first voltage sampling interval corresponding to the first voltage dividing resistor sub-module 310 and the first upward biasing resistor sub-module 310. The withstand voltage value of the resistor is determined.

In one embodiment, in the above-mentioned first voltage division sampling module 310, the ratio of the resistance value of the first resistance sub-module to the resistance value of the above-mentioned first lower bias resistance sub-module 312 is the first resistance value ratio, and the above-mentioned first resistance value ratio The resistance value of the resistor sub-module is the sum of the resistance value of the first upper bias resistor sub-module 311 and the resistance value of the first lower bias resistor sub-module 312, and the first resistance ratio corresponds to the first voltage divider sampling module. The voltage amplification ratio corresponding to any two of the above N voltage-dividing sampling modules is different.

Among the N voltage division sampling modules, the larger the midpoint value of the voltage sampling interval corresponding to the voltage division sampling module, the larger the corresponding voltage amplification ratio.

The controller 240 in this embodiment of the present application may refer to a programmable digital microprocessor such as a single-chip microcomputer, a digital signal processor (Digital Signal Processor, DSP). When the controller 240 works, the output voltage is monitored in real time. If the output voltage specification of the DC voltage output circuit 200 is 100-900V, and N is equal to 3, the N voltage division sampling modules include: voltage division sampling module 1 , voltage division sampling module 2 , and voltage division sampling module 3 . When the monitoring output voltage is in the range of 100-400V, the controller uses the voltage divider sampling module 1 as the input of the sampling signal of the output voltage. 2 as the input of the sampling signal of the output voltage, when the monitored output voltage is in the range of 700-1000V, the controller performs a switching operation, and uses the voltage divider sampling module 3 as the input of the sampling signal of the output voltage. Among them, the voltage amplification ratios corresponding to the voltage division sampling module 1, the voltage division sampling module 2 and the voltage division sampling module 3 are different, and the voltage amplification ratio of the voltage division sampling module 1 is smaller than that of the voltage division sampling module 2. The voltage amplification ratio of the voltage division sampling module The voltage amplification ratio of 2 is smaller than the voltage amplification ratio of the voltage dividing sampling module 3 . For example, the controller 240 is a 12-bit DSP, and the A/D sampling value ranges from 0 to 4096. If the DSP reference is 3.3V, then each sample is 3.3÷4096≈0.0008V. If the sampling is not performed in sections, the sampling signal amplitude range is 0.3-2.7V, corresponding to 100-400V, the sampling signal amplitude is 0.3-0.9V, and the A/D sampling value can be adjusted to 0.9-0.3=0.6V; when After adopting the voltage subsection sampling of the present application, the corresponding sampling signal amplitude is 1-3V, and the adjustable range of the A/D value is 3-1=2V. By comparison, it can be seen that the range of the adjustable A/D sampling value of the latter is much larger, which significantly improves the control precision of the output voltage.

In one embodiment, the above-mentioned power conversion circuit includes a transformer T1 and a switch Q1.

The transformer T1 includes a primary winding and a secondary winding, the input power end Uin is connected to the first end of the primary winding, the controller 240 is connected to the first end of the switch Q1, and the second end of the switch Q1 is connected to the primary The second end of the winding, the third end of the switch tube Q1 is grounded, the first end of the secondary winding is connected to the first end 221 of the rectifier filter circuit 220 , and the second end of the secondary winding is connected to the rectifier filter circuit 220 the second end 222.

The controller 240 adjusts the voltage amplitude of the output power terminal Uout by outputting a pulse width modulation signal to the second end of the switch Q1 and adjusting the duty cycle of the pulse width modulation signal.

Optionally, the above-mentioned switch transistor Q1 includes any one of a relay, a triode, or a metal oxide semiconductor (metal oxide semiconductor, MOS) transistor. As shown in FIG. 3 , the above-mentioned switch transistor Q1 is an N-type metal-oxide-semiconductor (NMOS) transistor, the gate of the NMOS transistor is the second end of the switch transistor, and the drain of the NMOS transistor is the gate of the switch transistor The first end, the source of the NMOS tube is the third end of the switch tube.

In one embodiment, the above-mentioned rectifying and filtering circuit 220 includes a diode D1 and a capacitor C1. The capacitor C1 included in the rectification filter circuit 220 may be a non-polar capacitor or a polar capacitor.

The third terminal of the power conversion circuit 210 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the first terminal of the capacitor C1, the multiple input terminals of the voltage sampling circuit 230, and the output power terminal Uout. The second terminal of C1 is connected to the fourth terminal of the power conversion circuit 210 and the ground.

Optionally, the capacitor C1 is a polar capacitor, the first end of the polar capacitor is a positive electrode, and the second end of the polar capacitor is a negative electrode.

In an implementation manner, the first end of the primary winding and the second end of the secondary winding are ends of the same polarity. The electromotive force generated in the primary winding and the secondary winding have opposite polarities, and when the switch tube is turned off, the rectifier and filter circuit outputs a DC voltage.

2 to 3 , the working principle of the DC voltage output circuit 200 provided by the present application will be described below.

The voltage sampling circuit 230 includes N voltage division sampling modules, and each voltage division sampling module corresponds to a voltage sampling interval. For example, when the voltage sampling circuit samples a voltage range of 0-900V, and the voltage sampling circuit has 3 voltage divisions When sampling modules, the first voltage sampling interval of the first voltage division sampling module is [0, 300), and the unit is volts, and the voltage sampling interval of the second voltage division sampling module is [300, 600), and the unit is volts. The voltage sampling interval of the voltage divider sampling module is [600, 900], and the unit is volts.

Optionally, the setting of the voltage sampling interval may be non-uniform. For example, when the voltage range for sampling by the voltage sampling circuit is 0-900V, and the voltage sampling circuit has three voltage-dividing sampling modules, the first voltage-dividing sampling is performed. The first voltage sampling interval of the module is set to [0, 100], the voltage sampling interval of the second voltage dividing sampling module is set to (100, 400), and the voltage sampling interval of the third voltage dividing sampling module is set to [400, 900].

When the controller 240 detects the target voltage sampling interval in which the output voltage falls, the specific process for the controller 240 to determine that the output voltage falls into the target voltage sampling interval is as follows: the controller 240 obtains the detected sampling voltage in the maximum voltage sampling interval, and the maximum voltage sampling interval is The voltage sampling interval in which the sampled output voltage value is the largest, for example, in the voltage sampling interval [0, 300), [300, 600), [600, 900], the sampling interval is [600, 900] the maximum voltage sampling interval. The voltage division sampling module corresponding to the maximum voltage sampling interval is the maximum voltage division sampling module, and the detected sampling voltage is amplified according to the voltage amplification ratio of the maximum voltage division sampling module, and the controller 240 can obtain the detected initial output voltage, and the initial output voltage falls. The incoming voltage sampling interval is the target voltage sampling interval in which the output voltage falls.

Different voltage divider sampling modules sample the same output voltage, and the output sampling voltage values are different. The voltage divider sampling module attenuates the fixed voltage attenuation ratio of the output voltage, and the input terminal voltage value of the voltage divider sampling module times the voltage attenuation ratio is equal to The voltage value of the output terminal of the voltage dividing sampling module, when the output voltage for sampling falls within the voltage sampling range of the voltage dividing sampling module, the voltage output by the voltage dividing sampling module meets the sampling range requirement of the controller 240 . The controller 240 amplifies the initial sampled voltage output by the voltage sampling circuit with the target amplification ratio to obtain the final sampled voltage, the voltage attenuation ratio of the target voltage divider sampling module corresponding to the initial sampled voltage is the target attenuation ratio, and the product of the target amplification ratio and the target attenuation ratio is 1.

Wherein, after the voltage sampling interval of the voltage dividing sampling module is determined, the voltage attenuation ratio of the voltage dividing sampling module can be determined by the maximum value of the voltage sampling interval, for example, the voltage sampling interval is [0, 300), the unit is volts, and the The sampling voltage is generally below 3V, and the voltage attenuation ratio can be 0.01. Further, the voltage to be endured by the upper biaser module is determined according to the voltage attenuation ratio and the voltage sampling interval, and the number of resistors included in the upper biaser module is determined according to the withstand voltage value of the resistors included in the upper biaser module.

The voltage divider sampling module divides the voltage by setting the upper bias resistor sub-module and the lower bias resistor sub-module. When the resistance value of the upper bias resistor sub-module is Ru, and the resistance value of the lower bias resistor sub-module is Rd, the voltage divider sampling When the input voltage of the module is Ui, and the output voltage of the voltage divider sampling module is Uo, the output voltage of the voltage divider sampling module Uo=(Rd/(Ru+Rd))*Ui. The voltage attenuation ratio of the voltage divider sampling module is: Rd/(Ru+Rd), and the voltage amplification ratio corresponding to the voltage divider sampling module is: (Ru+Rd)/Rd.

The comparison module in the controller 240 compares the final sampled voltage with the reference voltage. The reference voltage is the preset demand output voltage of the switching power supply. When the final sampled voltage is greater than the reference voltage, the controller 240 reduces the PWM output to the switching tube. signal, when the final sampled voltage is smaller than the reference voltage, the controller 240 increases the PWM signal output to the switch.

Optionally, the number of turns of the primary winding and the secondary winding of the transformer T1 may be the same or different. Under the condition that the primary winding and the secondary winding of the transformer T1 have the same number of turns, the first end of the primary winding and the second end of the secondary winding are of the same polarity, and the duty cycle of the PWM signal is D, Uout=(D/ (1-D))*Uin. The duty cycle refers to the proportion of the power-on time relative to the total time in a pulse cycle. The duty cycle is a positive number less than 1. When the duty cycle increases, the output voltage Uout increases, and when the duty cycle decreases, the output voltage Uout decreases.

Compared with the existing DC voltage output circuit, the embodiment of the present application provides a DC voltage output circuit, which includes an input power supply terminal, a controller, a power conversion circuit, a rectification filter circuit, a voltage sampling circuit and an output power supply terminal, wherein, The voltage sampling circuit uses multiple voltage division sampling modules to attenuate the voltages in different ranges of the wide-range output voltage according to different proportions, and adopts voltage segmentation sampling to ensure that the sampled voltage amplitudes in each voltage range meet the controller's requirements. The sampling accuracy is required to improve the accuracy of the sampling voltage. The controller controls the voltage amplitude output of the power conversion circuit according to the sampling voltage fed back by the voltage sampling circuit, so that the switching power supply can output a stable voltage.

As shown in FIG. 4 , the present application further provides a DC voltage output method, which is applied to the DC voltage output circuit shown in FIG. 2 or FIG. 3 , and the method may include:

401. The controller determines a target voltage sampling interval into which the output voltage of the DC voltage output circuit falls, and a target voltage division sampling module corresponding to the target voltage sampling interval.

402. The controller determines the target sampling voltage sampled by the target voltage division sampling module as the initial sampling voltage of the voltage sampling circuit.

403. The controller determines a target amplification ratio corresponding to the target sampling voltage module according to the corresponding relationship between the voltage division sampling module and the voltage amplification ratio.

404. The controller amplifies the initial sampling voltage according to the target amplification ratio to obtain the final sampling voltage of the voltage sampling circuit.

405. The controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result.

In one embodiment, the controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result, specifically: when the final sampled voltage is greater than the reference voltage, the controller controls the power conversion The circuit reduces the output voltage amplitude; when the final sampled voltage is less than the reference voltage, the controller controls the power conversion circuit to increase the output voltage amplitude.

In one embodiment, when the final sampled voltage is greater than the reference voltage, the controller controls the power conversion circuit to reduce the output voltage amplitude, specifically: when the final sampled voltage is greater than the reference voltage, the controller reduces the PWM output to the switch tube The duty cycle of the signal to reduce the voltage amplitude output by the power conversion circuit.

In one embodiment, when the final sampled voltage is less than the reference voltage, the controller controls the power conversion circuit to increase the output voltage amplitude, specifically: when the final sampled voltage is less than the reference voltage, the controller increases the output voltage to the switch tube. The duty cycle of the PWM signal increases the amplitude of the voltage output by the power conversion circuit.

The embodiments of the present application have been described in detail above, and specific examples are used to illustrate the principles and implementations of the present application. The descriptions of the above embodiments are only used to help understand the core idea of the present application; According to the idea of the present application, there will be changes in the specific embodiments and application scope for those skilled in the art. To sum up, the content of this specification should not be construed as a limitation on the present application.

Claims

A DC voltage output circuit, applied to a switching power supply, is characterized in that, the DC voltage output circuit comprises: an input power supply terminal, a controller, a power conversion circuit, a rectification filter circuit, a voltage sampling circuit and an output power supply terminal;

The voltage sampling circuit includes N voltage division sampling modules, each of the voltage division sampling modules corresponds to a voltage sampling interval, and the voltage sampling intervals corresponding to any two of the voltage division sampling modules have no intersection; the first voltage division sampling module comprising a first input end and a first output end; the first voltage-dividing sampling module is any one of the N voltage-dividing sampling modules;

The input power supply terminal is connected to the first terminal of the power conversion circuit; the controller is connected to the second terminal of the power conversion circuit; the third terminal of the power conversion circuit is connected to the first terminal of the rectifier and filter circuit ; the fourth end of the power conversion circuit is connected to the second end of the rectifier filter circuit; the third end of the rectifier filter circuit is connected to a plurality of input ends of the voltage sampling circuit and the output power supply end; the a plurality of output terminals of the voltage sampling circuit are connected to the controller;

The controller is used for obtaining the final sampling voltage of the voltage sampling circuit according to the corresponding relationship between the voltage dividing sampling module and the voltage amplification ratio; and for adjusting the final sampling voltage according to the relationship between the final sampling voltage and the reference voltage the voltage amplitude of the power conversion circuit, and for controlling the power conversion circuit to reduce the output voltage amplitude when the final sampled voltage is greater than the reference voltage; and for when the final sampled voltage is less than the reference voltage When , the controller controls the power conversion circuit to increase the output voltage amplitude.
The DC voltage output circuit according to claim 1, wherein the first voltage division sampling module comprises a first upper bias resistor sub-module and a first lower bias resistor sub-module;

The third end of the rectifier and filter circuit is connected to the first end of the first upper bias resistor sub-module; the second end of the first upper bias resistor sub-module is connected to the first end of the first lower bias resistor sub-module The terminal is connected to the controller; the second terminal of the first lower bias resistor sub-module is grounded.
The DC voltage output circuit according to claim 2, wherein the first upper bias resistor sub-module comprises at least one resistor; the first lower bias resistor sub-module comprises at least one resistor.
The DC voltage output circuit according to claim 2, wherein, in the first voltage division sampling module, the ratio of the resistance value of the first resistance sub-module to the resistance value of the first lower bias resistance sub-module is the first resistance value ratio, and the resistance value of the first resistance sub-module is the sum of the resistance value of the first upper-bias resistance sub-module and the resistance value of the first lower-bias resistance sub-module; The resistance ratio is the voltage amplification ratio corresponding to the first voltage division sampling module; the voltage amplification ratios corresponding to any two of the N voltage division sampling modules are different.
The DC voltage output circuit according to claim 1, wherein the power conversion circuit comprises a transformer and a switch;

The transformer includes a primary winding and a secondary winding; the input power end is connected to the first end of the primary winding; the controller is connected to the first end of the switch tube; the second end of the switch tube is connected to the the second end of the primary winding; the third end of the switch tube is grounded; the first end of the secondary winding is connected to the first end of the rectifier and filter circuit; the second end of the secondary winding is connected to the the second end of the rectifier filter circuit;

The controller adjusts the voltage amplitude of the output power supply terminal by outputting a pulse width modulation signal to the second end of the switch tube and adjusting the duty cycle of the pulse width modulation signal.
The DC voltage output circuit according to claim 5, wherein the switch tube comprises any one of a relay, a triode or a MOS tube.
The DC voltage output circuit according to claim 1, wherein the rectifier filter circuit comprises a diode and a capacitor;

The third end of the power conversion circuit is connected to the anode of the diode; the cathode of the diode is connected to the first end of the capacitor, a plurality of input ends of the voltage sampling circuit and the output power supply end; The second end is connected to the fourth end of the power conversion circuit and the ground.
The DC voltage output circuit according to claim 1, wherein, among the N voltage division sampling modules, the larger the midpoint value of the voltage sampling interval corresponding to the voltage division sampling module, the larger the corresponding voltage amplification ratio. .
A method for outputting a DC voltage, applied to the DC voltage output circuit according to any one of claims 1-8, wherein the method comprises:

The controller determines a target voltage sampling interval in which the output voltage of the DC voltage output circuit falls and a target voltage division sampling module corresponding to the target voltage sampling interval;

obtaining, by the controller, a target sampling voltage sampled by the target voltage division sampling module, where the target sampling voltage is an initial sampling voltage of the voltage sampling circuit;

The controller determines a target amplification ratio corresponding to the target sampling voltage module according to the corresponding relationship between the voltage division sampling module and the voltage amplification ratio;

The controller amplifies the initial sampling voltage according to the target amplification ratio to obtain the final sampling voltage of the voltage sampling circuit;

The controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result.
The method for outputting a DC voltage according to claim 9, wherein the controller compares the magnitude relationship between the final sampled voltage and the reference voltage, and adjusts the voltage amplitude output by the power conversion circuit according to the comparison result, include:

When the final sampled voltage is greater than the reference voltage, the controller controls the power conversion circuit to reduce the output voltage amplitude;

When the final sampled voltage is smaller than the reference voltage, the controller controls the power conversion circuit to increase the output voltage amplitude.