Adjustable voltage output circuit and electronic device

Abstract

The utility model provides a kind of adjustable voltage output circuit and electronic equipment, the adjustable voltage output circuit includes:R-2R resistance network and low dropout linear regulator circuit;The ground end of the R-2R resistance network is grounded, and the output end is connected with the voltage reference end of the low dropout linear regulator circuit;The output end of the low dropout linear regulator circuit is connected with load;The R-2R resistance network is used to form the adjusting voltage corresponding to the voltage instruction under the condition of receiving voltage instruction, and output to the low dropout linear regulator circuit;The low dropout linear regulator circuit is used to superimpose the adjusting voltage with basic voltage and output.The utility model realizes low cost control the different voltage values output by the low dropout linear regulator circuit by outputting voltage instruction to R-2R resistance network.

Description

Technical Field

[0001] This utility model relates to the field of voltage output circuit technology, and in particular to an adjustable voltage output circuit and electronic device. Background Technology

[0002] In automated testing systems, it is often necessary to provide power to devices with different voltages. Traditional LDOs cannot achieve automatic control of the output voltage. A DAC chip is required to convert the digital signal into an analog signal to provide a reference voltage for the LDO in order to achieve the function of providing different voltage values. The circuit is relatively complex and the cost is relatively high. Utility Model Content

[0003] The main purpose of this invention is to provide an adjustable voltage output circuit that aims to provide different voltage values ​​at low cost.

[0004] To achieve the above objectives, the present invention proposes an adjustable voltage output circuit, which includes:

[0005] R-2R resistor network and low dropout linear regulator circuit;

[0006] The ground terminal of the R-2R resistor network is grounded, and its output terminal is connected to the voltage reference terminal of the low dropout linear regulator circuit; the output terminal of the low dropout linear regulator circuit is connected to the load.

[0007] The R-2R resistor network is used to generate an regulated voltage corresponding to the received voltage command and output it to the low dropout linear regulator circuit.

[0008] The low-dropout linear regulator circuit is used to superimpose the regulated voltage with the base voltage and output it.

[0009] This invention also proposes an electronic device, which includes the adjustable voltage output circuit. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the first embodiment of the adjustable voltage output circuit of this utility model;

[0012] Figure 2This is a schematic diagram of the second embodiment of the adjustable voltage output circuit of this utility model;

[0013] Figure 3 This is a schematic diagram of the first structure of the third embodiment of the adjustable voltage output circuit of this utility model;

[0014] Figure 4 This is a schematic diagram of the second structure of the third embodiment of the adjustable voltage output circuit of this utility model;

[0015] Figure 5 This is a schematic diagram of the first structure of the fourth embodiment of the adjustable voltage output circuit of this utility model;

[0016] Figure 6 This is a schematic diagram of the second structure of the fourth embodiment of the adjustable voltage output circuit of this utility model;

[0017] Figure 7 This is a schematic diagram of the fifth embodiment of the adjustable voltage output circuit of this utility model.

[0018] Explanation of icon numbers:

[0019]

[0020] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0025] This utility model provides an adjustable voltage output circuit. In a first embodiment, the adjustable voltage output circuit includes:

[0026] R-2R resistor network 10 and low dropout linear regulator circuit 20;

[0027] The ground terminal of the R-2R resistor network 10 is grounded, and its output terminal is connected to the voltage reference terminal of the low dropout linear regulator circuit 20; the output terminal of the low dropout linear regulator circuit 20 is connected to the load.

[0028] The R-2R resistor network 10 is used to generate an regulated voltage corresponding to the received voltage command and output it to the low dropout linear regulator circuit 20.

[0029] The low-dropout linear regulator circuit 20 is used to superimpose the regulated voltage with the base voltage and output it.

[0030] It needs to be explained that the R-2R resistor network 10 is a circuit that uses two resistance values ​​(a first resistance value R and a second resistance value 2R) to form a ladder structure, and achieves precise binary current division through its unique equivalent resistance characteristics (each node has the first resistance value R when viewed from the right). Here, R is a basic resistance value. The topology of the R-2R resistor network 10 has the following characteristics: (1) The network is in the shape of a ladder. (2) Vertical arms: Each node is connected by a resistor with a resistance value of R (along the direction of the ladder). (3) Horizontal arms: A resistor branch with a resistance value of 2R is led out from each node, and its end is connected to the switch of the corresponding bit. (4) The most significant bit (MSB) is usually connected to the input / reference terminal of the network. The switch of the least significant bit (LSB) branch is usually directly grounded or grounded through a 2R resistor.

[0031] The R-2R resistor network 10 has a unique characteristic of constant equivalent resistance: the equivalent input resistance looking to the right (i.e., towards the LSB) from any node in the network is equal to R. This characteristic propagates leftwards stage by stage, ensuring that the equivalent resistance looking to the right from each node is R. This is the basis for the precise binary distribution of current. Regardless of how many stages (number of bits) are connected after a node, and regardless of the state of the subsequent switches (0 or 1), this equivalent resistance remains constant at R.

[0032] Furthermore, the constant equivalent resistance described above generates a binary weighted current. Since the equivalent resistance of each node looking to the right is R, and the resistance of its branch is 2R, according to the principle of parallel current division: the total current I_in flowing into the node from the left will be precisely divided into two equal currents I_in / 2 at this node. One path (I_in / 2) flows downward into the 2R branch of this node. The other path (I_in / 2) flows to the right into the R resistance of the next node. This division process repeats at every node. Therefore, the branch current (I_bit) corresponding to each bit is half of the branch current (I_bit-1) of its previous bit (higher significant bit), and these current values ​​form a perfect binary weighting relationship.

[0033] This invention does not limit the number of bits in the R-2R resistor network 10. In one example, the R-2R resistor network 10 has 8 inputs, i.e., it is an 8-bit R-2R resistor network 10.

[0034] The R-2R resistor network 10 is used to generate an regulated voltage corresponding to the received voltage command and output it to the low dropout linear regulator circuit 20.

[0035] It should be noted that the voltage command refers to the potential at each input terminal of the R-2R resistor network 10;

[0036] Reference Figure 1, Figure 1 An 8-bit R-2R resistor network 10 is shown. The ends of the horizontal arms of the 8-bit R-2R resistor network 10 are the input terminals of the resistor network. Accordingly, the 8-bit R-2R resistor network 10 has eight input terminals; due to the characteristics of the R-2R resistor network 10, the voltage combination formed by the potentials of the eight input terminals can determine the voltage value at the output terminal of the R-2R resistor network 10. The eight input terminals can be equivalent to a byte bit0 to bit7, the size of which ranges from 0 to 255, dividing the voltage regulation levels into 0 to 255 (a total of 256 levels, the lowest output voltage of the circuit is the base voltage). In one example, the hardware design has determined that for each additional level, the final output voltage of the low dropout linear regulator circuit 20 increases by 50mV, and the output voltage Uo = base voltage + 50mV. If all eight inputs of the R-2R resistor network 10 are high, the output voltage is the lowest, i.e., output voltage Uo = Ubase + ((255-255)*50mV) = Ubase. Here, Ubase is the base voltage value. If all eight inputs of the R-2R resistor network 10 are low, the output voltage is the highest, i.e., output voltage Uo = Ubase + ((255-0)*50mV) = Ubase + 12750mV. The base voltage is the lowest voltage value that the low-dropout linear regulator circuit 20 can output, and can be zero.

[0037] The low-dropout linear regulator circuit 20 is used to superimpose the regulated voltage with the base voltage and output it. The R-2R resistor network 10 is used to generate a regulated voltage corresponding to the received voltage command and output it to the low-dropout linear regulator circuit 20. This allows different voltage values ​​to be provided by adjusting the voltage command output to the R-2R resistor network 10; specifically, by changing the voltage combination formed at each input terminal of the R-2R resistor network 10. Because the R-2R resistor network 10 replaces the digital-to-analog converter, different voltage values ​​can be provided at a low cost.

[0038] The low dropout linear regulator circuit 20 may include an LDO chip, and in one example, the LDO chip may be a TPS7A4700RGWR.

[0039] This invention provides an adjustable voltage output circuit, comprising: an R-2R resistor network 10 and a low-dropout linear regulator circuit 20; the ground terminal of the R-2R resistor network 10 is grounded, and its output terminal is connected to the voltage reference terminal of the low-dropout linear regulator circuit 20; the output terminal of the low-dropout linear regulator circuit 20 is connected to a load; the R-2R resistor network 10 is used to generate an adjusted voltage corresponding to a received voltage command and output it to the low-dropout linear regulator circuit 20; the low-dropout linear regulator circuit 20 is used to superimpose the adjusted voltage with a base voltage and output it. This invention achieves low-cost control of the low-dropout linear regulator circuit 20 to output different voltage values ​​by outputting a voltage command to the R-2R resistor network 10.

[0040] In the second embodiment, as Figure 2 As shown, the adjustable voltage output circuit further includes: an IO expansion unit 30;

[0041] The multiple input terminals of the R-2R resistor network 10 are connected one by one to the same number of output terminals of the IO expansion unit 30;

[0042] The IO expansion unit 30 is used to output a corresponding voltage command to the R-2R resistor network 10 when the voltage adjustment signal is received.

[0043] It is easy to understand that the input terminals of the R-2R resistor network 10 can be connected to the output ports of the controller. The multiple input terminals of the R-2R resistor network 10 are connected one-to-one to the same number of output ports. Therefore, the controller can change the potential of the output ports connected to the R-2R resistor network 10 to implement output voltage commands, thereby adjusting the output voltage value of the low-dropout linear regulator circuit 20. Since the controller mainly relies on its output ports to transmit data or commands to connected modules or devices, in order to improve the utilization rate of the controller's output ports and achieve the goal of outputting voltage commands to the R-2R resistor network 10 with as few controller output ports as possible, the second embodiment uses an IO expansion unit 30 connected to the R-2R resistor network 10. The IO expansion unit 30 may include an IO expansion chip, such as a TCA6424 chip. It is readily understood that the IO expansion unit 30 can output a corresponding voltage command to the R-2R resistor network 10 based on the voltage adjustment signal received at its input terminal. For example, the controller communicates with the IO expansion unit 30 and outputs data to the IO expansion unit 30, indicating the voltage command that the IO expansion unit 30 needs to output, i.e., the potential of the output terminal of the IO expansion unit 30 connected to the R-2R resistor network 10. Therefore, the IO expansion unit 30 can process the received voltage adjustment signal and output the corresponding voltage command. The voltage adjustment signal can be a data signal. In particular, the controller and the IO expansion unit 30 are connected via IIC, and the controller outputs a data signal to the IO expansion unit 30 as a voltage adjustment signal through IIC communication. Furthermore, the IO expansion unit 30 has multiple output terminals and can connect to multiple R-2R resistor networks 10 to control multiple low-dropout linear regulator circuits 20 to output multiple voltages. Each R-2R resistor network 10 is connected to a corresponding low-dropout linear regulator circuit 20.

[0044] The controller can be an MCU, SOC, FPGA, or DSP, etc.

[0045] In the third embodiment, as Figure 3 As shown, there are multiple R-2R resistor networks 10, and the number of low-dropout linear regulator circuits 20 is equal to the number of R-2R resistor networks 10;

[0046] The plurality of R-2R resistor networks 10 are connected one-to-one with the plurality of low dropout linear regulator circuits 20;

[0047] Each of the multiple input terminals of the R-2R resistor network 10 is connected to the output terminals of the same number of IO expansion units 30;

[0048] The number of output terminals of the IO expansion unit 30 is greater than or equal to the number of input terminals of all R-2R resistor networks 10.

[0049] It is readily understood that in this embodiment, the IO expansion unit 30 is connected to multiple R-2R resistor networks 10, and each of the multiple R-2R resistor networks 10 is connected one-to-one to multiple low-dropout linear regulator circuits 20, thus constructing multiple voltage output channels. Specifically, the IO expansion unit 30 can output corresponding voltage commands to each of the multiple R-2R resistor networks 10 upon receiving a voltage adjustment signal. The voltage adjustment signal contains information about multiple voltage commands.

[0050] Furthermore, the number of output terminals of the IO expansion unit 30 needs to be greater than or equal to the number of input terminals of all R-2R resistor networks 10. This ensures that the multiple input terminals of each R-2R resistor network 10 are connected one-to-one with the output terminals of the same number of IO expansion units 30. It should be noted that in this embodiment, the number of bits in each R-2R resistor network 10 is not limited, and the number of bits in multiple R-2R resistor networks 10 can be different; for example, there can be 8-bit R-2R resistor networks 10 and 13-bit R-2R resistor networks 10.

[0051] In one example of this utility model, the R-2R resistor network 10 may have 8 input terminals, that is, an 8-bit R-2R resistor network 10.

[0052] like Figure 4 As shown, the R-2R resistor network 10 includes: a first resistor R1 to a sixteenth resistor R16;

[0053] The first end of the first resistor R1 is connected to the first output terminal of the IO expansion unit 30, and the second end is connected to the voltage reference terminal of the low dropout linear regulator circuit 20 and the first end of the second resistor R2; the second end of the second resistor R2 is connected to the second end of the third resistor R3 and the first end of the fourth resistor R4; the second end of the fourth resistor R4 is connected to the second end of the fifth resistor R5 and the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the second end of the seventh resistor R7 and the first end of the eighth resistor R8; the second end of the eighth resistor R8 is connected to the second end of the ninth resistor R9 and the first end of the tenth resistor R10; the second end of the tenth resistor R10 is connected to the second end of the eleventh resistor R11 and the first end of the twelfth resistor R12; the second end of the twelfth resistor R12 is connected to the second end of the thirteenth resistor R13 and the first end of the fourteenth resistor R14; the second end of the fourteenth resistor R14 is connected to the second end of the fifteenth resistor R15 and the first end of the sixteenth resistor R16.

[0054] The second terminal of the sixteenth resistor R16 is grounded; the first terminal of the third resistor R3 is connected to the second output terminal of the IO expansion unit 30; the first terminal of the fifth resistor R5 is connected to the third output terminal of the IO expansion unit 30; the first terminal of the seventh resistor R7 is connected to the fourth output terminal of the IO expansion unit 30; the first terminal of the ninth resistor R9 is connected to the fifth output terminal of the IO expansion unit 30; the first terminal of the eleventh resistor R11 is connected to the sixth output terminal of the IO expansion unit 30; the first terminal of the thirteenth resistor R13 is connected to the seventh output terminal of the IO expansion unit 30; and the first terminal of the fifteenth resistor R15 is connected to the eighth output terminal of the IO expansion unit 30.

[0055] Specifically, the values ​​of the first resistor R1, the third resistor R3, the fifth resistor R5, the seventh resistor R7, the ninth resistor R9, the eleventh resistor R11, the thirteenth resistor R13, the fifteenth resistor R15, and the sixteenth resistor R16 are the same; the values ​​of the second resistor R2, the fourth resistor R4, the sixth resistor R6, the eighth resistor R8, the tenth resistor R10, the twelfth resistor R12, and the fourteenth resistor R14 are the same. Furthermore, the value of the first resistor R1 is twice the value of the second resistor R2.

[0056] In one feasible example, the first resistor R1 can be 20K and the second resistor R2 can be 10K.

[0057] In the fourth embodiment, the low dropout linear regulator circuit 20 includes a low dropout linear regulator chip, a first capacitor C1 to a third capacitor C3, and a seventeenth resistor R17.

[0058] The voltage reference terminal of the low dropout linear regulator chip is connected to the output terminal of the R-2R resistor network 10. The first terminal of the first capacitor C1 is connected to the power input terminal of the low dropout linear regulator chip, and the second terminal is grounded. The first terminal of the second capacitor C2 is connected to the output terminal of the low dropout linear regulator chip and the first terminal of the seventeenth resistor R17, and the second terminal is grounded. The first terminal of the third capacitor C3 is connected to the second terminal of the seventeenth resistor R17 and the load, and the second terminal is grounded.

[0059] like Figure 5As shown, in one example, the low-dropout linear regulator chip can be a TPS7A4700RGWR. The first capacitor C1 is located between the power input terminal and ground; the power input terminal is used to connect the operating voltage of the low-dropout linear regulator chip. The first capacitor C1 is used for energy storage and buffering, suppressing input voltage drops and improving transient response. The second capacitor C2 is located between the output terminal and ground; the output terminal is used to output voltage to the load. The second capacitor C2 is used to suppress noise and filter out high-frequency noise. The seventeenth resistor R17 is located between the output terminal and the load for current limiting. The third capacitor C3 is used to stabilize the voltage value output from the output terminal to the load.

[0060] The adjustable voltage output circuit further includes: a voltage regulator unit;

[0061] The input terminal of the voltage regulator unit is connected to the power supply voltage, and the output terminal is connected to the power input terminal of the low dropout linear voltage regulator circuit 20. The voltage regulator unit is used to filter out high-frequency noise in the power supply voltage and stabilize the output power supply voltage to the low dropout linear voltage regulator circuit 20.

[0062] It is understood that the output voltage stability of the low-dropout linear regulator circuit 20 is affected by changes in the operating voltage. The voltage regulator unit is used to output a stable power supply voltage to the low-dropout linear regulator circuit 20. Compared to directly connecting the power supply voltage to the low-dropout linear regulator circuit 20, using a voltage regulator unit for power supply can avoid power supply voltage fluctuations that could affect the output voltage stability of the low-dropout linear regulator circuit 20.

[0063] In one example, such as Figure 6 As shown, the voltage regulator unit includes a precision voltage reference chip, an eighth capacitor, and a ninth capacitor; specifically, the precision voltage reference chip is a REF3033. The input terminal of the precision voltage reference chip is connected to the power supply voltage, the output terminal is connected to the power input terminal of the low-dropout linear regulator circuit 20, and the ground terminal is grounded. The first terminal of the eighth capacitor is connected to the input terminal of the precision voltage reference chip, and the second terminal is grounded; the first terminal of the ninth capacitor is connected to the output terminal of the precision voltage reference chip. The eighth and ninth capacitors are used for filtering and voltage regulation.

[0064] In the fifth embodiment, the adjustable voltage output circuit further includes: a voltage conversion circuit;

[0065] The input terminal of the voltage conversion circuit is connected to the output terminal of the voltage regulator unit, and the output terminal is connected to the power input terminal of the IO expansion unit 30. The voltage conversion circuit is used to convert the voltage at the output terminal of the voltage regulator unit into the operating voltage required by the IO expansion unit 30, and then output it to the IO expansion unit 30.

[0066] It is readily understood that the operating voltage of the IO expansion unit 30 may differ from the operating voltage of the low-dropout linear regulator circuit 20. To avoid providing separate operating voltages for the IO expansion unit 30 and the low-dropout linear regulator circuit 20, this embodiment utilizes a voltage conversion circuit to convert the power supply voltage into the operating voltage of the IO expansion unit 30, thereby improving power supply voltage utilization and reducing the number of power supplies required for the device containing the adjustable voltage output circuit.

[0067] In one example, the voltage conversion circuit includes: eighteenth resistor R18 to twenty-third resistor, fourth capacitor C4 to seventh capacitor C7, variable resistor RT, and operational amplifier U1;

[0068] The eighteenth resistor R18 and the nineteenth resistor R19 are connected in parallel. The first end of the eighteenth resistor R18 is connected to the output terminal of the voltage regulator unit, and the second end is connected to the first end of the fourth capacitor C4, the first end of the twentieth resistor R20, and the non-inverting input terminal of the operational amplifier U1. The second end of the fourth capacitor C4 is connected to the second end of the variable resistor RT and grounded. The second end of the twentieth resistor R20 is connected to the first end of the variable resistor RT. The first end of the twenty-first resistor R21 is connected to the first voltage, and the second end is connected to the positive input terminal of the power supply of the operational amplifier U1 and the first end of the fifth capacitor C5. The second end of the fifth capacitor C5 is connected to the negative input terminal of the power supply of the operational amplifier U1 and grounded. The first end of the twenty-second resistor R22 is connected to the inverting input terminal of the operational amplifier U1, and the second end is grounded. The first end of the twenty-third resistor R23 is connected to the inverting input terminal of the operational amplifier U1, and the second end is connected to the output terminal of the operational amplifier U1. The sixth capacitor C6 is connected in parallel to the twenty-third resistor R23. The first end of the seventh capacitor C7 is connected to the output terminal of the operational amplifier U1, and the second end is grounded.

[0069] like Figure 7 As shown, Figure 7This is a structural diagram of the voltage conversion circuit in this example. It should be noted that the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20, the fourth capacitor C4, and the variable resistor RT constitute a voltage divider circuit. Specifically, the twentieth resistor R20 and the variable resistor RT are connected in series and then in parallel with the fourth capacitor C4, which in turn divides the voltage with the eighteenth resistor R18 and the nineteenth resistor R19. The voltage value at the output of the voltage regulator unit, after being divided, is output to the non-inverting input of the operational amplifier U1. Additionally, the fourth capacitor C4 can be used for filtering and voltage regulation; the eighteenth resistor R18 and the nineteenth resistor R19 are used for current limiting. Considering the limited current carrying capacity of a single resistor, the eighteenth resistor R18 and the nineteenth resistor R19 are connected in parallel. It is easy to understand that the resistance value of the variable resistor RT can be changed, thereby changing the voltage division coefficient of the voltage divider circuit, and thus changing the voltage value output to the non-inverting input.

[0070] The 21st resistor R21 and the 5th capacitor C5 are connected in series between the first voltage and ground potential. The 21st resistor R21 is used for current limiting to prevent large currents from being generated. The two ends of the 5th capacitor C5 are respectively connected to the positive and negative input terminals of the power supply of the operational amplifier U1, and are used to generate a voltage difference across them to maintain a stable voltage difference between the positive and negative input terminals of the power supply. It is easy to understand that the ratio of the value of the 6th capacitor C6, the value of the 22nd resistor R22, and the value of the 23rd resistor R23 affects the voltage gain of the operational amplifier U1. The 7th capacitor C7 is used for voltage regulation. The first voltage is determined by the researchers based on the operating voltage of the operational amplifier U1 and the 21st resistor R21 and the 5th capacitor C5.

[0071] This utility model also proposes an electronic device, which includes a power supply component and the aforementioned adjustable voltage output circuit. The specific structure of the adjustable voltage output circuit is as described in the above embodiments. Since this electronic device adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0072] The power supply component can be used to provide the first voltage and the power supply voltage.

[0073] The above description is only an optional embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An adjustable voltage output circuit, characterized in that, The adjustable voltage output circuit includes: R-2R resistor network and low dropout linear regulator circuit; The ground terminal of the R-2R resistor network is grounded, and its output terminal is connected to the voltage reference terminal of the low dropout linear regulator circuit; the output terminal of the low dropout linear regulator circuit is connected to the load. The R-2R resistor network is used to generate an regulated voltage corresponding to the received voltage command and output it to the low dropout linear regulator circuit. The low-dropout linear regulator circuit is used to superimpose the regulated voltage with the base voltage and output it.

2. The adjustable voltage output circuit as described in claim 1, characterized in that, The adjustable voltage output circuit further includes: an I / O expansion unit; The multiple input terminals of the R-2R resistor network are connected one by one to the same number of output terminals of the IO expansion unit; The IO expansion unit is used to output a corresponding voltage command to the R-2R resistor network when the voltage adjustment signal is received.

3. The adjustable voltage output circuit as described in claim 2, characterized in that, The number of R-2R resistor networks is multiple, and the number of low-dropout linear regulator circuits is equal to the number of R-2R resistor networks; The multiple R-2R resistor networks are connected one-to-one to the multiple low-dropout linear regulator circuits; Each input terminal of the R-2R resistor network is connected to the output terminals of the same number of IO expansion units; The number of output terminals of the IO expansion unit is greater than or equal to the number of input terminals of all R-2R resistor networks.

4. The adjustable voltage output circuit as described in any one of claims 1 to 3, characterized in that, The R-2R resistor network has 8 input terminals.

5. The adjustable voltage output circuit as described in claim 4, characterized in that, The R-2R resistor network includes: a first resistor to a sixteenth resistor; The first terminal of the first resistor is connected to the first output terminal of the IO expansion unit, and the second terminal is connected to the voltage reference terminal of the low dropout linear regulator circuit and the first terminal of the second resistor; the second terminal of the second resistor is connected to the second terminal of the third resistor and the first terminal of the fourth resistor; the second terminal of the fourth resistor is connected to the second terminal of the fifth resistor and the first terminal of the sixth resistor; the second terminal of the sixth resistor is connected to the second terminal of the seventh resistor and the first terminal of the eighth resistor; the second terminal of the eighth resistor is connected to the second terminal of the ninth resistor and the first terminal of the tenth resistor; the second terminal of the tenth resistor is connected to the second terminal of the eleventh resistor and the first terminal of the twelfth resistor; the second terminal of the twelfth resistor is connected to the second terminal of the thirteenth resistor and the first terminal of the fourteenth resistor; the second terminal of the fourteenth resistor is connected to the second terminal of the fifteenth resistor and the first terminal of the sixteenth resistor. The second terminal of the sixteenth resistor is grounded; the first terminal of the third resistor is connected to the second output terminal of the IO expansion unit; the first terminal of the fifth resistor is connected to the third output terminal of the IO expansion unit; the first terminal of the seventh resistor is connected to the fourth output terminal of the IO expansion unit; the first terminal of the ninth resistor is connected to the fifth output terminal of the IO expansion unit; the first terminal of the eleventh resistor is connected to the sixth output terminal of the IO expansion unit; the first terminal of the thirteenth resistor is connected to the seventh output terminal of the IO expansion unit; and the first terminal of the fifteenth resistor is connected to the eighth output terminal of the IO expansion unit.

6. The adjustable voltage output circuit as described in any one of claims 1 to 3, characterized in that, The low-dropout linear regulator circuit includes a low-dropout linear regulator chip, a first capacitor to a third capacitor, and a seventeenth resistor. The voltage reference terminal of the low dropout linear regulator chip is connected to the output terminal of the R-2R resistor network. The first terminal of the first capacitor is connected to the power input terminal of the low dropout linear regulator chip, and the second terminal is grounded. The first terminal of the second capacitor is connected to the output terminal of the low dropout linear regulator chip and the first terminal of the seventeenth resistor, and the second terminal is grounded. The first terminal of the third capacitor is connected to the second terminal of the seventeenth resistor and the load, and the second terminal is grounded.

7. The adjustable voltage output circuit as described in claim 2, characterized in that, The adjustable voltage output circuit further includes: a voltage regulator unit; The input terminal of the voltage regulator unit is connected to the power supply voltage, and the output terminal is connected to the power input terminal of the low dropout linear voltage regulator circuit. The voltage regulator unit is used to filter out high-frequency noise in the power supply voltage and stabilize the output power supply voltage to the low dropout linear voltage regulator circuit.

8. The adjustable voltage output circuit as described in claim 7, characterized in that, The adjustable voltage output circuit further includes: a voltage conversion circuit; The input terminal of the voltage conversion circuit is connected to the output terminal of the voltage regulator unit, and the output terminal is connected to the power input terminal of the IO expansion unit. The voltage conversion circuit is used to convert the voltage at the output terminal of the voltage regulator unit into the operating voltage required by the IO expansion unit and then output it to the IO expansion unit.

9. The adjustable voltage output circuit as described in claim 8, characterized in that, The voltage conversion circuit includes: resistors eighteen to twenty-three, capacitors four to seven, a variable resistor, and an operational amplifier; The eighteenth and nineteenth resistors are connected in parallel. The first end of the eighteenth resistor is connected to the output terminal of the voltage regulator unit, and the second end is connected to the first end of the fourth capacitor, the first end of the twentieth resistor, and the non-inverting input terminal of the operational amplifier. The second end of the fourth capacitor is connected to the second end of the variable resistor and grounded. The second end of the twentieth resistor is connected to the first end of the variable resistor. The first end of the twenty-first resistor is connected to the first voltage, and the second end is connected to the positive power input terminal of the operational amplifier and the first end of the fifth capacitor. The second end of the fifth capacitor is connected to the negative power input terminal of the operational amplifier and grounded. The first end of the twenty-second resistor is connected to the inverting input terminal of the operational amplifier, and the second end is grounded. The first end of the twenty-third resistor is connected to the inverting input terminal of the operational amplifier, and the second end is connected to the output terminal of the operational amplifier. The sixth capacitor is connected in parallel with the twenty-third resistor. The first end of the seventh capacitor is connected to the output terminal of the operational amplifier, and the second end is grounded.

10. An electronic device, characterized in that, The electronic device includes a power supply component and an adjustable voltage output circuit as described in any one of claims 1 to 9.

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