Current injection hybrid DAC converter with wide output voltage range and conversion method

Abstract

The present invention belongs to the field of DAC, and specifically relates to a current injection hybrid DAC converter with a wide output voltage range and a conversion method. A converter provided by the present invention includes a reference current injection module Iref, a resistor string module, a control module, a voltage adjustment module and an error amplification module; the input end of the reference current injection module Iref is connected to an external voltage VDD, the output end is connected to the input end of the resistor string module, and is connected to the FB end through the control module; the output end of the resistor string module is grounded; the output end of the voltage adjustment module is used as the output end of the DAC converter; the input end of the error amplification module is connected to an external reference voltage Vref, and the connection end is connected to the connection end of the voltage adjustment module; the digital end of the resistor string module and the control end of the control module are used to connect to an external digital input signal. The present invention combines current injection with a resistor string, and by selecting appropriate resistance values ​​and current values, the purpose of output voltage less than 0.6V is achieved, and the requirement of extremely low output voltage of DAC is realized.

Description

Technical Field

[0001] The invention relates to a DAC converter, in particular to a current injection hybrid DAC converter with a wide output voltage range and a conversion method. Background Art

[0002] A DAC converter (Digital-to-Analog Converter) is a device that converts digital quantities into analog quantities. In recent years, a new DAC structure has emerged: current-input DAC, which mainly uses segmented current sources to achieve high speed and resolution. Its working principle is to control the current generated by current sources with different bit weights by inputting digital codes, and the current output converts digital signals into analog signals. Its core unit is the current source array. The built-in DAC decoder drives the differential current switch at each DAC refresh, so that the current source array has two current outputs. The two outputs are complementary, which improves the dynamic performance and ensures its linearity while increasing the speed. The disadvantages of this current output DAC are: for an N-bit DAC, 2 N -1 current source, the static loss is large; at the same time, when the current of the binary weight of the DAC input is large, it will produce a large static error, resulting in insufficient accuracy of the output analog signal.

[0003] Most of the existing DC / DC power modules have a minimum output voltage of 0.7V. The internal DAC selects a resistor string DAC structure. The output voltage control schematic is shown in the figure. Figure 1 shown.

[0004] For an N-bit DAC digital control code, the corresponding output voltage control principle of the resistor string DAC structure is: the N-bit digital control code controls the switch of the resistor string to ensure that the output voltage increases the voltage on the resistor to be connected based on the FB voltage. Figure 1 In the figure, Vref is connected to the non-inverting input of the error amplifier EA, and the inverting input of the error amplifier is at the FB level. The compensation network of EA is connected between the inverting input and output of EA. Through the compensation network, the error amplifier EA clamps the voltage at the FB point at Vref, that is, V FB = Vref. The output voltage of the resistor string DAC structure is controlled by the DAC input digital code, such as Figure 1 K0, K1, K2, and K3 in the circuit respectively correspond to the four states after decoding the N-bit digital. If the lowest two bits of the N-bit digital are 00, K0, K01, and K03 will be turned on, and the other switches will be turned off, and the output V OUT =V R1 +V FBIf the lowest 2 bits of N are 11, K3, K23, and K03 will be turned on, and the other switches will be turned off, and the output V OUT =V R1 +V R2 +V R3 +V R4 +V FB For other higher output voltages, Figure 1 More resistor strings are stacked on the R4 resistor, and other higher DAC bits are used to control the conduction of the corresponding switches. Through the analysis of the output voltage of the resistor string DAC structure, it can be seen that the existing technology is based on the FB voltage, and the control of the voltage greater than FB is achieved through the resistor string.

[0005] The existing resistor string DAC structure has a control mode for the output voltage, which requires that the output voltage is always higher than V FB As users demand higher battery life in electronic products, the output voltage requirements for power supplies are getting lower and lower. For example, in order to improve the efficiency of PA power supply, many APT products require the output voltage to reach 0.4V or 0.5V. The existing resistor string DAC structure requires the output voltage to be higher than V FB The output voltage is too high to meet the requirement of 0.4V or 0.5V, and it is also unable to meet the demand for higher battery life in electronic products. Today, most power supplies have a 0.6V reference, namely V FB =0.6V, which means the output voltage must be greater than 0.6V. For applications where the output voltage is required to be 0.4V or 0.5V, a reference voltage source lower than 0.4V or 0.5V needs to be specially designed. The topology is relatively complex and the process selection requirements are also very high, making it difficult to implement. Summary of the invention

[0006] The purpose of the present invention is to solve the problem of the existing resistor string DAC converter's control mode of output voltage, which requires the output voltage to be higher than V FB The technical problem that the output voltage is high and 0.4V or 0.5V cannot be achieved is solved, and a current injection hybrid DAC converter with a wide output voltage range and a conversion method are provided.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] The present invention provides a current injection hybrid DAC converter with a wide output voltage range, which is special in that:

[0009] It includes a reference current injection module Iref, a resistor string module, a control module, a voltage adjustment module and an error amplification module;

[0010] The reference current injection module Iref is used to provide current for the voltage adjustment module, and its input terminal is connected to the external voltage VDD, and its output terminal is connected to the input terminal of the resistor string module, and is connected to the FB terminal through the control module; the output terminal of the resistor string module is grounded; the FB terminal is the input terminal of the voltage adjustment module;

[0011] The voltage adjustment module is used to adjust the voltage at the FB terminal and output it. Its output terminal is used as the output terminal of the DAC converter to output the voltage V out ;

[0012] The error amplification module is used to make the voltage at the FB terminal equal to the reference voltage Vref through feedback regulation, and its input terminal is connected to the external reference voltage Vref, and the connection terminal of the error amplification module is connected to the connection terminal of the voltage adjustment module;

[0013] The digital end of the resistor string module and the control end of the control module are used to receive an external digital input signal. The resistor string module adjusts its resistance value according to the digital input signal, and the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital input signal.

[0014] Further, the resistor string module includes a plurality of switches and a plurality of resistors connected in series in sequence;

[0015] One of the resistors at both ends is grounded, and the other resistor is connected to the output end of the reference current injection module Iref through at least one switch, and a connection node is set between the two adjacent resistors, and the connection node is connected to the output end of the reference current injection module Iref through at least one switch.

[0016] Further, the control module includes a resistor R15 and a switch K03 connected in sequence;

[0017] One end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal and control its on / off state according to the digital input signal;

[0018] The resistor string module includes a switch K0, a switch K1, a switch K2, a switch K3, a switch K01, a switch K23, and resistors R11, R12, R13, and R14 connected in series in sequence;

[0019] The control ends of switch K0, switch K1, switch K2, switch K3, switch K01 and switch K23 are used as digital ends of the resistor string module, and are used to receive external digital input signals respectively;

[0020] One end of the resistor R11 and the resistor R12 are connected to one end of the switch K0, the other end of the resistor R11 is grounded, the other end of the resistor R12 and one end of the resistor R13 are connected to one end of the switch K1, and the other ends of the switch K0 and the switch K1 are connected to one end of the switch K01; one end of the resistor R14 is connected to one end of the switch K3, the other ends of the resistor R14 and the resistor R13 are connected to one end of the switch K2, and the other ends of the switch K2 and the switch K3 are connected to one end of the switch K23; the other ends of the switch K01 and the switch K23 are connected to the output end of the reference current injection module Iref;

[0021] The reference current injection module Iref includes a MOS tube M1, a MOS tube M2, a MOS tube M3, a resistor R30, and an operational amplifier OP;

[0022] The non-inverting input terminal of the operational amplifier OP is used to connect to the external reference voltage Vref2, the inverting input terminal is connected to the source of the MOS tube M1, the source of the MOS tube M1 is grounded through the resistor R30, the gate of the MOS tube M1 is connected to the output terminal of the operational amplifier OP, the drain of the MOS tube M1 is connected to the drain of the MOS tube M2, the gate and the drain of the MOS tube M2 are short-circuited, the gate of the MOS tube M2 is connected to the gate of the MOS tube M3, the sources of the MOS tubes M2 and M3 are both used to connect to the external voltage VDD, the drain of the MOS tube M3 is used as the output terminal of the reference current injection module Iref, and is connected to the other ends of the switch K01 and the switch K23 and one end of the resistor R15;

[0023] The voltage adjustment module includes a resistor R0 and a resistor R10;

[0024] One end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB terminal. The other end of the resistor R10 serves as the output end of the DAC converter for outputting the voltage V out ; The other end of resistor R0 is grounded;

[0025] The error amplification module includes an error amplifier EA and a compensation network;

[0026] The non-inverting input terminal of the error amplifier is connected to the external reference voltage Vref, the inverting input terminal is connected to the FB terminal, and the output terminal of the error amplifier is fed back to its inverting input terminal through the compensation network.

[0027] Based on the above-mentioned current injection hybrid DAC converter with wide output voltage range, the present invention provides a current injection hybrid DAC conversion method with wide output voltage range, which is special in that it includes the following steps:

[0028] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0029] Step 2, sending the edited digital input signal to the resistor string module and the control module, the resistor string module adjusts its resistance value according to the digital input signal, and the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital input signal;

[0030] Step 3, outputting a reference current through a reference current injection module Iref, and then shunting the reference current through a resistor string module and a control module;

[0031] Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0032] Step 5: Use the voltage adjustment module to divide the voltage at the FB terminal to obtain the output voltage V out .

[0033] The present invention also provides another current injection hybrid DAC converter with a wide output voltage range, which is special in that:

[0034] It includes a first resistor string module, a second resistor string module, a reference current injection module Iref, a voltage adjustment module, an error amplification module and a control module;

[0035] The reference current injection module Iref is used to provide current for the voltage adjustment module, and its input end is connected to the external voltage VDD, and its output end is connected to the input end of the first resistor string module, and is connected to the FB end through the control module; the output end of the first resistor string module is grounded; the FB end is the input end of the voltage adjustment module;

[0036] The voltage adjustment module is used to adjust the voltage at the FB terminal and output it. Its first output terminal is connected to the input terminal of the second resistor string module. The second output terminal of the voltage adjustment module and the output terminal of the second resistor string module are used as the output terminal of the DAC converter to output the voltage V out ;

[0037] The error amplification module is used to make the voltage at the FB terminal equal to the reference voltage Vref through feedback regulation, and its input terminal is connected to the external reference voltage Vref, and the connection terminal of the error amplification module is connected to the connection terminal of the voltage adjustment module;

[0038] The digital end of the first resistor string module, the digital end of the second resistor string module, the control end of the control module and the control end of the voltage adjustment module are respectively used to receive external digital input signals. The first resistor string module and the second resistor string module adjust their respective resistance values ​​according to the digital signals. The control module controls the on-off state between the reference current injection module Iref and the resistor string module and the voltage adjustment module according to the digital signals. The voltage adjustment module controls the on-off state between itself and the second resistor string module according to the digital signals.

[0039] Further, the first resistor string module includes a plurality of first switches and a plurality of first resistors sequentially connected in series;

[0040] One end of one of the first resistors at both ends is grounded, one end of the other first resistor is connected to the output end of the reference current injection module Iref through at least one first switch, and a first connection node is provided between two adjacent first resistors, and the first connection node is connected to the output end of the reference current injection module Iref through at least one first switch;

[0041] The second resistor string module includes a plurality of second switches and a plurality of second resistors connected in series in sequence;

[0042] One end of one of the second resistors located at both ends serves as the input end of the second resistor string module, and is connected to the output end of the voltage adjustment module with one end of the switch K04 respectively, and is connected to the other end of the switch K04 through at least one third switch, and one end of the other second resistor is connected to the other end of the switch K04 through at least one third switch; a second connection node is provided between two adjacent second resistors, and the second connection node is connected to the other end of the switch K04 through at least one third switch.

[0043] Further, the control module includes a resistor R15 and a switch K03 connected in sequence;

[0044] One end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal and control its on / off state according to the digital input signal;

[0045] The voltage adjustment module includes a switch K04, a resistor R0 and a resistor R10;

[0046] One end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB terminal, and the other end of the resistor R10 is connected to one end of the switch K04; the other end of the switch K04 serves as the output end of the voltage adjustment module, and the other end of the resistor R0 is grounded;

[0047] The second resistor string module includes a switch K4, a switch K5, a switch K6, a switch K7, a switch K45, a switch K67, a switch K47, and a resistor R6, a resistor R7, and a resistor R8 connected in series in sequence;

[0048] The control ends of switch K4, switch K5, switch K6, switch K7, switch K45, switch K67 and switch K47 serve as digital ends of the second resistor string module, and are used to receive external digital input signals respectively;

[0049] One end of the resistor R6 is used as the input end of the second resistor string module, connected to the output end of the voltage adjustment module, and connected to one end of the switch K4; the other end of the resistor R6 and one end of the resistor R7 are connected to one end of the switch K5, the other end of the resistor R7 and one end of the resistor R8 are connected to one end of the switch K6, and the other end of the resistor R8 is connected to one end of the switch K7;

[0050] The other ends of switch K4 and switch K5 are connected to one end of switch K45, the other ends of switch K6 and switch K7 are connected to one end of switch K67, and the other ends of switch K45 and switch K67 are connected to one end of switch K47;

[0051] The other end of the switch K47 is connected to the other end of the switch K04;

[0052] The first resistor string module includes a switch K0, a switch K1, a switch K2, a switch K3, a switch K01, a switch K23, and a resistor R11, a resistor R12, a resistor R13, and a resistor R14 connected in series in sequence;

[0053] The control ends of switch K0, switch K1, switch K2, switch K3, switch K01 and switch K23 serve as digital ends of the first resistor string module, and are used to receive external digital input signals respectively;

[0054] One end of the resistor R11 and the resistor R12 are connected to one end of the switch K0, the other end of the resistor R11 is grounded, the other end of the resistor R12 and one end of the resistor R13 are connected to one end of the switch K1, and the other ends of the switch K0 and the switch K1 are connected to one end of the switch K01; one end of the resistor R14 is connected to one end of the switch K3, the other ends of the resistor R14 and the resistor R13 are connected to one end of the switch K2, and the other ends of the switch K2 and the switch K3 are connected to one end of the switch K23; the other ends of the switch K01 and the switch K23 are connected to the output end of the reference current injection module Iref.

[0055] Furthermore, the reference current injection module Iref includes a MOS tube M1, a MOS tube M2, a MOS tube M3, a resistor R30, and an operational amplifier OP;

[0056] The non-inverting input terminal of the operational amplifier OP is used to connect to the external reference voltage Vref2, the inverting input terminal is connected to the source of the MOS tube M1, the source of the MOS tube M1 is grounded through the resistor R30, the gate of the MOS tube M1 is connected to the output terminal of the operational amplifier OP, the drain of the MOS tube M1 is connected to the drain of the MOS tube M2, the gate and the drain of the MOS tube M2 are short-circuited, the gate of the MOS tube M2 is connected to the gate of the MOS tube M3, the sources of the MOS tubes M2 and M3 are both used to connect to the external voltage VDD, the drain of the MOS tube M3 is used as the output terminal of the reference current injection module Iref, and is connected to the input terminal of the first resistor string module and one end of the resistor R15;

[0057] The error amplification module includes an error amplifier EA and a compensation network;

[0058] The non-inverting input terminal of the error amplifier is connected to the reference voltage Vref, the inverting input terminal is connected to the FB terminal, and the output terminal of the error amplifier is fed back to its inverting input terminal through the compensation network.

[0059] Based on the above-mentioned current injection hybrid DAC converter with wide output voltage range, the present invention provides another current injection hybrid DAC conversion method with wide output voltage range, which is special in that it includes the following steps:

[0060] When the required output voltage V out When it is less than or equal to 0.6V;

[0061] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0062] Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the first resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref, the first resistor string module and the voltage adjustment module according to the digital signal to be connected, and the voltage adjustment module controls the second resistor string module to be disconnected according to the digital signal;

[0063] Step 3, outputting a reference current through a reference current injection module Iref, and then shunting the reference current through a first resistor string module and a control module;

[0064] Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0065] Step 5: Divide the voltage at the FB terminal by the voltage adjustment module to obtain the output voltage Vout;

[0066] When the required output voltage V out When greater than 0.6V:

[0067] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0068] Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the second resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref according to the digital signal, and the first resistor string module and the voltage adjustment module are disconnected, and the voltage adjustment module controls the second resistor string module to be connected according to the digital signal;

[0069] Step 3: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0070] Step 4: The voltage at the FB terminal is boosted for the first time by the voltage adjustment module and output to the second resistor string module;

[0071] Step 5: The voltage at the FB terminal is boosted multiple times through the second resistor string module to obtain the required output voltage V out .

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] 1. The solution of the present application designs a hybrid DAC that combines current injection type and resistor string in the circuit. By selecting appropriate resistance values ​​and current values, the output voltage is less than 0.6V, realizing the requirement of extremely low output voltage of DAC.

[0074] 2. In order to broaden the range of output voltage, the scheme of the present application only selects the resistor string module for the state requiring the output voltage to be greater than 0.6V, thereby reducing the diversity of resistance changes and improving the accuracy of the output voltage. At the same time, the DAC has the characteristics of simple structure and high reliability.

[0075] 3. In order to eliminate the error caused by current injection in the solution of the present application, a reference current injection module is specially designed. The reference current injection module makes the reverse input voltage of the operational amplifier equal to the forward reference voltage value through the regulation of the feedback MOS tube M1, and then copies the current on R30 through the mirroring effect of the current mirror, and obtains the reference current Iref at the output end of the current mirror. The reference current injection module realizes the required injection current by selecting resistors of the same type and square resistance as the resistor string in the DAC, thereby reducing the influence of process, temperature and voltage on the output voltage.

[0076] 4. The hybrid DAC converter proposed in the solution of the present application, while meeting the requirements of extremely low output voltage, broadens the output voltage range by using a combination of current injection and resistor string, thereby greatly increasing the power supply output voltage range while improving power supply efficiency and battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 is a circuit diagram of an existing resistor string DAC converter;

[0078] Figure 2 It is a circuit diagram of the design idea of ​​the present invention;

[0079] Figure 3 is a circuit diagram of a reference current injection module in an embodiment of the present invention;

[0080] Figure 4 is a circuit diagram of Embodiment 1 of the present invention;

[0081] Figure 5 is a circuit diagram of Embodiment 2 of the present invention;

[0082] Figure 6 It is the output waveform diagram of the existing resistor string DAC converter;

[0083] Figure 7 This is an output waveform diagram of the second embodiment of the present invention. DETAILED DESCRIPTION

[0084] In order to make the purpose, advantages and features of the present invention more clear, the following is a further detailed description of a current injection hybrid DAC converter with a wide output voltage range and a conversion method proposed by the present invention in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will be more clear according to the following specific implementation methods.

[0085] The design idea of ​​the present invention is to inject current to increase the output voltage V out Reduce to voltage V FB Below, the specific structure of this design idea refers to Figure 2 , including a reference current injection module Iref, a resistor R15, a resistor R20, a voltage adjustment module and an error amplification module.

[0086] Among them, the error amplification module includes an error amplifier EA and a compensation network; the non-inverting input terminal of the error amplifier is connected to the external reference voltage Vref, the inverting input terminal is connected to the FB terminal, the output terminal of the error amplifier is fed back to its inverting input terminal through the compensation network, and the FB level of the inverting input terminal of the error amplifier is clamped to be equal to the external reference voltage Vref of its non-inverting input terminal through the negative feedback regulation effect of the compensation network.

[0087] The voltage adjustment module includes a resistor R0 and a resistor R10; one end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB terminal, and the other end of the resistor R10 is used as the output end of the DAC converter for outputting a voltage V out ; The other end of resistor R0 is grounded.

[0088] The input end of the reference current injection module Iref is used to connect to the external voltage VDD, and the output end is connected to one end of the resistor R15 and the resistor R20; the other end of the resistor R20 is grounded, and the other end of the resistor R15 is connected to the input end of the voltage adjustment module, and the input end of the voltage adjustment module is the aforementioned FB end.

[0089] Working principle:

[0090] The external reference voltage Vref is usually 0.6V, which is connected to the non-inverting input of the error amplifier EA. The inverting input of the error amplifier EA is the voltage FB. Through the compensation network, the error amplifier EA clamps the voltage of its inverting input at 0.6V, that is, V FB =Vref=0.6V.

[0091] The current injected by the reference current injection module Iref is first divided by resistors R15 and R20, and is divided into I4 and I3, where I4 is the current flowing through resistor R20, and I3 is the current flowing through R15. Secondly, the current I3 is divided by resistors R10 and R0, and is divided into I1 and I2, where I1 is the current flowing through R0, and I2 is the current flowing through R1. Since the current of I2 flows upward from the FB terminal to the OUT terminal, V is realized by injecting the reference current Iref. OUT Lower than V FB Voltage requirements.

[0092] By combining the following equations:

[0093] Iref=I4+I3

[0094] I3=I1+I2

[0095] V1=R20*I4

[0096] V1-V FB =R15*I3

[0097] V FB =R0*I1=V ref =0.6V

[0098] V OUT =V FB -R10*I2

[0099] It can be concluded that:

[0100] V OUT =0.6+I1*R10-(R20*Iref-0.6)R10 / (R15+R20)

[0101] It can be seen from the above formula that by selecting the appropriate resistance value and current value, V OUT <V ref =0.6V purpose.

[0102] Taking R0=60K, R10=5K, I1=10uA, R15=10K, we can get the parameter table of the corresponding devices in this DAC converter, as shown in Table 1.

[0103] Table 1

[0104] R0 R1 R15 R20 Iref I1 I2 I3 I4 <![CDATA[V OUT ]]> 60K 5K 10K 100K 50uA 10uA 30uA 40uA 10uA 0.45V 60K 5K 10K 45K 50uA 10uA 20uA 30uA 20uA 0.5V 60K 5K 10K 26.67K 50uA 10uA 10uA 20uA 30uA 0.55V 60K 5K 10K 17.5K 50uA 10uA 0 10uA 40uA 0.6V

[0105] In order to eliminate the error caused by reference current injection, a reference current injection module Iref is specially designed. By selecting resistors of the same type and square resistance as the resistor string in the DAC, the required current can be injected to reduce the influence of process, temperature and voltage on the output voltage.

[0106] Specific structure such as Figure 3 As shown, in this embodiment, the reference current injection module Iref includes a MOS transistor M1, a MOS transistor M2, a MOS transistor M3, a resistor R30, and an operational amplifier OP.

[0107] Among them, the MOS tube M1 is an NMOS tube, and the MOS tube M2 and the MOS tube M3 are both PMOS tubes.

[0108] The non-inverting input terminal of the operational amplifier OP is used to connect to the external reference voltage Vref2, the inverting input terminal is connected to the source of the MOS tube M1, the source of the MOS tube M1 is grounded through the resistor R30, the gate of the MOS tube M1 is connected to the output terminal of the operational amplifier OP, the drain of the MOS tube M1 is connected to the drain of the MOS tube M2, the gate and the drain of the MOS tube M2 are short-circuited, the gate of the MOS tube M2 is connected to the gate of the MOS tube M3, the sources of the MOS tubes M2 and M3 are both used to connect to the external voltage VDD, the drain of the MOS tube M3 is used as the output terminal of the reference current injection module Iref, and is connected to the resistor R15 and one end of the resistor R20.

[0109] The function of MOS tube M1 is to provide negative feedback to the operational amplifier OP, so that V R30 = Vref2, MOS tube M2 and MOS tube M3 are current mirrors, copying I R30 The current makes Iref=I R30 =Vref2 / R30.

[0110] In order to eliminate the error caused by current injection and reduce the influence of process, temperature and voltage on the output voltage, the square resistance of R30 is selected and Figure 2 R0, R10, R15, and R20 are of the same type and have the same square resistance.

[0111] Embodiment 1

[0112] In order to achieve the control of the DAC converter digital code corresponding to each output voltage below 0.6V, this embodiment provides a current injection hybrid DAC converter with a wide output voltage range. Figure 4 As shown, it includes a reference current injection module Iref, a control module, a voltage adjustment module and an error amplification module, and the aforementioned R20 is replaced by a resistor string module, so that the resistance value of R20 is easily adjusted.

[0113] The control module includes a resistor R15 and a switch K03 connected in sequence; one end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal, and its on-off state is controlled according to the digital input signal, thereby controlling the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module;

[0114] The resistor string module includes a plurality of switches and a plurality of resistors connected in series in sequence; one of the resistors at both ends is grounded, and the other resistor is connected to the output end of the reference current injection module Iref through at least one switch, and a connection node is provided between two adjacent resistors, and the connection node is connected to the output end of the reference current injection module Iref through at least one switch. In this embodiment, the resistor string module specifically includes switch K0, switch K1, switch K2, switch K3, switch K01, switch K23, and resistors R11, R12, R13, and R14 connected in series in sequence.

[0115] Specifically, one end of the resistor R11 and the resistor R12 are connected to one end of the switch K0, the other end of the resistor R11 is grounded, the other end of the resistor R12 and one end of the resistor R13 are connected to one end of the switch K1, and the other ends of the switch K0 and the switch K1 are connected to one end of the switch K01; one end of the resistor R14 is connected to one end of the switch K3, the other ends of the resistor R14 and the resistor R13 are connected to one end of the switch K2, and the other ends of the switch K2 and the switch K3 are connected to one end of the switch K23; the other end of the switch K01, the other end of the switch K23 and one end of the resistor R15 are connected to the output end of the reference current injection module Iref; the input end of the reference current injection module Iref is used to connect to the external voltage VDD; one end of the switch K03 is connected to the other end of the resistor R15, and the other end is connected to the FB end.

[0116] The output voltage of the DAC converter is adjusted by the digital code input by the DAC converter. The output of the DAC converter is connected to the DC / DC power supply, and finally the output voltage of the DC / DC power supply is adjusted. Figure 4 The switches K0-K3 are the four switch states corresponding to the lowest 2-bit digital code in the digital input signal input by the DAC converter, such as Figure 4 In the example, when the lowest 2-bit digital code in the digital input signal of the DAC converter is 00, switches K3, K23, and K03 are closed, and the output voltage V OUT =0.45V; when the lowest 2-bit digital code in the digital input signal of the DAC converter is 11, switches K0, K01, and K03 are closed, and the output V OUT=0.6V. The corresponding resistance values ​​of the four resistors R11, R12, R13, and R14 are shown in Table 2.

[0117] Table 2

[0118]

[0119]

[0120] Based on the above-mentioned current injection hybrid DAC converter with wide output voltage range, this embodiment provides a current injection hybrid DAC conversion method with wide output voltage range, which specifically includes the following steps:

[0121] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0122] Step 2, sending the edited digital input signal to the resistor string module and the control module, the resistor string module adjusts its resistance value according to the digital input signal, and the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital input signal;

[0123] Step 3, outputting a reference current through the reference current injection module Iref, and then shunting the reference current through the resistor string module and R15 in the control module;

[0124] Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0125] Step 5: Use the voltage adjustment module to divide the terminal voltage of FB to obtain the output voltage V out .

[0126] Embodiment 2

[0127] In order to realize the control of the DAC digital code corresponding to each output voltage, refer to Figure 5 In this embodiment, a current injection hybrid DAC converter with a wide output voltage range is provided. The resistor string module in the first embodiment is set as a first resistor string module, and on this basis, a second resistor string module is further set at the output end of the error amplification module, and the output end of the second resistor string module serves as the output end of the DAC converter.

[0128] The voltage adjustment module of this embodiment includes a switch K04, a resistor R0 and a resistor R10. When the voltage adjustment module needs to output a voltage less than or equal to 0.6V, the reference current module provides a reference current, and the current of the resistor R10 flows upward to divide the voltage at the FB end; if the output voltage needs to be greater than 0.6V, the current of R10 flows downward to boost the voltage of FB, and the potential of FB is less than the potential of the OUT end; one end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB end, and the other end of the resistor R10 is connected to one end of the switch K04; the other end of the switch K04 serves as the output end of the voltage adjustment module, and the other end of the resistor R0 is grounded; the control end of K04 is used to receive an external digital input signal, and its on-off state is controlled according to the digital input signal, thereby controlling the on-off state between the second resistor string module and the voltage adjustment module.

[0129] The control module includes a resistor R15 and a switch K03 connected in sequence; one end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal, and its on-off state is controlled according to the digital input signal, thereby controlling the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module;

[0130] The second resistor string module includes a plurality of second switches and a plurality of second resistors connected in series in sequence;

[0131] One end of one of the second resistors located at both ends serves as the input end of the second resistor string module, and is connected to the output end of the voltage adjustment module with one end of the switch K04 respectively, and is connected to the other end of the switch K04 through at least one third switch, and one end of the other second resistor is connected to the other end of the switch K04 through at least one third switch; a second connection node is provided between two adjacent second resistors, and the second connection node is connected to the other end of the switch K04 through at least one third switch.

[0132] Specifically, switch K0, switch K1, switch K2, switch K3, switch K01, switch K23, switch K03, and resistors R11, R12, R13 and R14 connected in series in sequence are the resistor string module in Example 1. In this embodiment, the resistor string module is defined as a first resistor string module.

[0133] A second resistor string module is formed by resistor R6, resistor R7, resistor R8, switch K4, switch K5, switch K6, switch K7, switch K45, switch K67, and switch K47.

[0134] Resistor R6, resistor R7 and resistor R8 are connected in series in sequence; one end of resistor R6 is used as the input end of the second resistor string module, connected to the output end of the voltage adjustment module, and connected to one end of switch K4; the other end of resistor R6 and one end of resistor R7 are connected to one end of switch K5, the other end of resistor R7 and one end of resistor R8 are connected to one end of switch K6, and the other end of resistor R8 is connected to one end of switch K7; the other ends of switch K4 and switch K5 are connected to one end of switch K45, the other ends of switch K6 and switch K7 are connected to one end of switch K67, and the other ends of switch K45 and switch K67 are connected to one end of switch K47; the other end of switch K47 is connected to the other end of switch K04.

[0135] When V OUT When the voltage is less than 0.6V, the decoded digital input signal from the DAC converter is selected from the 0th state to the 3rd state, respectively controlling the Figure 5 K0, K1, K2, and K3 are closed, and the rest of the switches are open.

[0136] When V OUT When the voltage is greater than 0.6V, the 4th to 7th states decoded in the digital input signal input by the DAC converter are selected to control Figure 5 K4, K5, K6, and K7 are closed, and the rest of the switches are open.

[0137] The reference current injection module Iref, the resistor R15 and the switch K03 form a current injection module, which is used to provide an input current for an output voltage lower than 0.6V, the second resistor string module is used to provide a voltage increment for an output voltage higher than 0.6V, and the error amplifier module is used to feedback and adjust the output voltage FB of the current injection module to make it equal to the set value (Vref). In the above hybrid DAC converter structure, when the output voltage is required to be lower than 0.6V, the current injection module and the error amplifier module work, wherein the reference current injection module Iref is used to generate a reference current, and the digital input signal input to the DAC converter controls the corresponding switch to be opened or closed, so that the output voltage can be less than 0.6V. When the output voltage is required to be greater than 0.6V, the second resistor string module and the error amplifier module work, and the digital input signal input to the DAC converter controls the corresponding switch to be opened or closed, so that the output voltage can be greater than 0.6V.

[0138] When the output voltage is required to be 0.7V, the 5th state decoded in the digital input signal of the DAC converter is corresponding to the closure of switches K5, K45 and K47, and the other switches are disconnected. out =V FB +V R6 +V R1 , due to V FB =0.6V, R0 = 60kΩ, and V R6 =VR1 =50mV, so at this time:

[0139] V out =V FB +V R6 +V R1 =0.6+0.05+0.05=0.7V, R10=R6=R7=R8=5kΩ.

[0140] In order to meet the requirements of Table 1 REF =50uF, and eliminate the error caused by current injection. A resistor with the same square resistance as that in the resistor network is used to realize the current that needs to be injected. Figure 3 The Iref current generation circuit selects V REF2 =0.9V, R30=18kΩ, making Iref=0.9 / 18=50uA.

[0141] Table 3

[0142] R0 R10 R6 R7 R8 Iref <![CDATA[V OUT ]]> 60K 5K / / / 50uA 0.65 60K 5K 5K / / 50uA 0.70 60K 5K 5K 5K / 50uA 0.75 60K 5K 5K 5K 5K 50uA 0.80

[0143] Based on the above-mentioned current injection hybrid DAC converter with a wide output voltage range, this embodiment provides another current injection hybrid DAC conversion method with a wide output voltage range, which specifically includes the following steps:

[0144] When the required output voltage V out When it is less than or equal to 0.6V;

[0145] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0146] Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the first resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref, the first resistor string module and the voltage adjustment module according to the digital signal to be connected, and the voltage adjustment module controls the second resistor string module to be disconnected according to the digital signal;

[0147] Step 3, outputting a reference current through the reference current injection module Iref, and then shunting the reference current through the first resistor string module and the resistor R15 in the control module;

[0148] Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0149] Step 5: Divide the voltage at the FB terminal by the voltage adjustment module to obtain the output voltage Vout;

[0150] When the required output voltage V out When greater than 0.6V:

[0151] Step 1: Output voltage V as required out Size, edit the corresponding digital input signal;

[0152] Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the second resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref according to the digital signal, and the first resistor string module and the voltage adjustment module are disconnected, and the voltage adjustment module controls the second resistor string module to be connected according to the digital signal;

[0153] Step 3: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module;

[0154] Step 4: The voltage at the FB terminal is boosted for the first time by the voltage adjustment module and output to the second resistor string module;

[0155] Step 5: The voltage at the FB terminal is boosted multiple times through the second resistor string module to obtain the required output voltage V out .

[0156] Figure 6 The output waveform of the existing DAC converter is shown in the figure. The horizontal axis is the DAC input code, and the vertical axis is the output voltage at the OUT terminal. The positive reference voltage of the error amplifier EA is 0.6V. For the control of the output voltage greater than the FB voltage, a resistor string is usually used to control the output voltage of the DAC structure. For other higher output voltages, this can be achieved by Figure 1 More resistor strings are stacked on the R4 resistor, and other higher DAC bits are used to control the opening and closing of the corresponding switches. It can be seen from the figure that the existing resistor string DAC converter can only achieve an output voltage greater than 0.6V, and cannot obtain an output voltage ≤0.6V.

[0157] Figure 7 The horizontal axis is the DAC input code, the vertical axis is the output voltage of the OUT terminal, and the positive reference voltage of the error amplifier EA is 0.6V; when the DAC code is 0000, the resistors R11-R14 are all connected, the switches K03, K23, and K3 are closed, and the output voltage V out is 0.45V; when the DAC code is 0001, switches K03, K23, and K2 are closed, resistors R11-R13 are connected, and the output voltage V outis 0.50V; when the DAC code is 0010, switches K01, K1, and K03 are closed, and only R11 and R12 are connected, and the output voltage V out is 0.55V; when the DAC code is 0011, switches K01, K0, and K03 are closed, and only resistor R11 is connected, and the output voltage V out is 0.6V, and the output voltage is equal to the reference voltage; when the DAC code is 0100, the second resistor string module works, R6-R8 are not connected, and the output voltage V out is 0.65V, which is higher than the reference voltage. When the DAC code is 0101, only resistor R6 is connected, and the output voltage V out is 0.70V; when the DAC code is 0110, resistors R6 and R7 are connected, and the output voltage V out is 0.75V; when the DAC code is 0111, resistors R6, R7 and R8 are all connected, and the output voltage V out It is 0.80V; and so on, when a higher output voltage is needed, more resistors can be set accordingly.

[0158] In summary, in the present invention, when the output voltage V out When the output voltage V out When ≤0.6V, the current injection module and error amplifier module in the DAC converter work, and the output voltage V is achieved by selecting the appropriate resistance value and current value. out In order to achieve the purpose of less than 0.6V and realize the requirement of extremely low output voltage of DAC, a current injection hybrid DAC combining current injection and resistor string is adopted, and the 0.6V reference is used. The circuit topology is simpler and the reliability is high.

Claims

1. A current injection hybrid DAC converter with a wide output voltage range, characterized in that: It includes a reference current injection module Iref, a resistor string module, a control module, a voltage adjustment module and an error amplification module; The reference current injection module Iref is used to provide current for the voltage adjustment module, and its input end is connected to the external voltage VDD, and its output end is connected to the input end of the resistor string module, and is connected to the FB end through the control module; the output end of the resistor string module is grounded; the FB end is the input end of the voltage adjustment module; The voltage adjustment module is used to adjust the voltage at the FB end and output it. Its output end is used as the output end of the DAC converter to output the voltage V out ; The error amplification module is used to make the voltage at the FB end equal to the reference voltage Vref through feedback regulation, and its input end is connected to the external reference voltage Vref, and the connection end of the error amplification module is connected to the connection end of the voltage adjustment module; The digital end of the resistor string module and the control end of the control module are used to receive an external digital input signal, the resistor string module adjusts its resistance value according to the digital input signal, and the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital input signal; The control module includes a resistor R15 and a switch K03 connected in sequence; One end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal and control its on / off state according to the digital input signal; The resistor string module includes a switch K0, a switch K1, a switch K2, a switch K3, a switch K01, a switch K23, and a resistor R11, a resistor R12, a resistor R13 and a resistor R14 connected in series in sequence; The control ends of the switches K0, K1, K2, K3, K01 and K23 are used as digital ends of the resistor string module, and are used to receive external digital input signals respectively; One end of the resistor R11 and the resistor R12 are connected to one end of the switch K0, the other end of the resistor R11 is grounded, the other end of the resistor R12 and one end of the resistor R13 are connected to one end of the switch K1, and the other ends of the switch K0 and the switch K1 are connected to one end of the switch K01; one end of the resistor R14 is connected to one end of the switch K3, the other ends of the resistor R14 and the resistor R13 are connected to one end of the switch K2, and the other ends of the switch K2 and the switch K3 are connected to one end of the switch K23; the other ends of the switch K01 and the switch K23 are connected to the output end of the reference current injection module Iref; The reference current injection module Iref includes a MOS tube M1, a MOS tube M2, a MOS tube M3, a resistor R30, and an operational amplifier OP; The non-inverting input terminal of the operational amplifier OP is used to connect to the external reference voltage Vref2, the inverting input terminal is connected to the source of the MOS tube M1, the source of the MOS tube M1 is grounded through the resistor R30, the gate of the MOS tube M1 is connected to the output terminal of the operational amplifier OP, the drain of the MOS tube M1 is connected to the drain of the MOS tube M2, the gate and the drain of the MOS tube M2 are short-circuited, the gate of the MOS tube M2 is connected to the gate of the MOS tube M3, the sources of the MOS tubes M2 and M3 are both used to connect to the external voltage VDD, the drain of the MOS tube M3 is used as the output terminal of the reference current injection module Iref, and is connected to the other ends of the switch K01 and the switch K23 and one end of the resistor R15; The voltage adjustment module includes a resistor R0 and a resistor R10; One end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB terminal. The other end of the resistor R10 serves as the output end of the DAC converter for outputting a voltage V out ; The other end of resistor R0 is grounded; The error amplification module includes an error amplifier EA and a compensation network; The non-inverting input terminal of the error amplifier is connected to an external reference voltage Vref, the inverting input terminal is connected to the FB terminal, and the output terminal of the error amplifier is fed back to the inverting input terminal thereof through a compensation network.

2. A current injection hybrid DAC conversion method with a wide output voltage range, based on the current injection hybrid DAC converter with a wide output voltage range as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Output voltage V as required out Size, edit the corresponding digital input signal; Step 2, sending the edited digital input signal to the resistor string module and the control module, the resistor string module adjusts its resistance value according to the digital input signal, and the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital input signal; Step 3, outputting a reference current through a reference current injection module Iref, and then shunting the reference current through a resistor string module and a control module; Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module; Step 5: Use the voltage adjustment module to divide the voltage at the FB terminal to obtain the output voltage V out .

3. A current injection hybrid DAC converter with a wide output voltage range, characterized in that: It includes a first resistor string module, a second resistor string module, a reference current injection module Iref, a voltage adjustment module, an error amplification module and a control module; The reference current injection module Iref is used to provide current for the voltage adjustment module, and its input end is connected to the external voltage VDD, and its output end is connected to the input end of the first resistor string module, and is connected to the FB end through the control module; the output end of the first resistor string module is grounded; the FB end is the input end of the voltage adjustment module; The voltage adjustment module is used to adjust the voltage at the FB end and then output it, and its first output end is connected to the input end of the second resistor string module; the second output end of the voltage adjustment module and the output end of the second resistor string module are used as the output end of the DAC converter to output the voltage V out ; The error amplification module is used to make the voltage at the FB end equal to the reference voltage Vref through feedback regulation, and its input end is connected to the external reference voltage Vref, and the connection end of the error amplification module is connected to the connection end of the voltage adjustment module; The digital end of the first resistor string module, the digital end of the second resistor string module, the control end of the control module and the control end of the voltage adjustment module are respectively used to receive external digital input signals, the first resistor string module and the second resistor string module adjust their respective resistance values ​​according to the digital signals, the control module controls the on-off state between the reference current injection module Iref, the resistor string module and the voltage adjustment module according to the digital signals, and the voltage adjustment module controls the on-off state between itself and the second resistor string module according to the digital signals; The first resistor string module includes a plurality of first switches and a plurality of first resistors connected in series in sequence; One end of one of the first resistors at both ends is grounded, one end of the other first resistor is connected to the output end of the reference current injection module Iref through at least one first switch, and a first connection node is provided between two adjacent first resistors, and the first connection node is connected to the output end of the reference current injection module Iref through at least one first switch; The second resistor string module includes a plurality of second switches and a plurality of second resistors connected in series in sequence; One end of one of the second resistors located at both ends serves as the input end of the second resistor string module, and is connected to the output end of the voltage adjustment module with one end of the switch K04 respectively, and is connected to the other end of the switch K04 through at least one third switch, and one end of the other second resistor is connected to the other end of the switch K04 through at least one third switch; a second connection node is provided between two adjacent second resistors, and the second connection node is connected to the other end of the switch K04 through at least one third switch; The control module includes a resistor R15 and a switch K03 connected in sequence; One end of the resistor R15 is connected to the output end of the reference current injection module Iref, one end of the switch K03 is connected to the FB end, and its control end is used to receive an external digital input signal and control its on / off state according to the digital input signal; The voltage adjustment module includes a switch K04, a resistor R0 and a resistor R10; One end of the resistor R10 is connected to one end of the resistor R0 and connected to the FB terminal, and the other end of the resistor R10 is connected to one end of the switch K04; the other end of the switch K04 serves as the output end of the voltage adjustment module, and the other end of the resistor R0 is grounded; The second resistor string module includes a switch K4, a switch K5, a switch K6, a switch K7, a switch K45, a switch K67, a switch K47, and a resistor R6, a resistor R7 and a resistor R8 connected in series in sequence; The control ends of the switches K4, K5, K6, K7, K45, K67 and K47 are used as digital ends of the second resistor string module, and are used to receive external digital input signals respectively; One end of the resistor R6 is used as the input end of the second resistor string module, connected to the output end of the voltage adjustment module, and connected to one end of the switch K4; the other end of the resistor R6 and one end of the resistor R7 are connected to one end of the switch K5, the other end of the resistor R7 and one end of the resistor R8 are connected to one end of the switch K6, and the other end of the resistor R8 is connected to one end of the switch K7; The other ends of the switches K4 and K5 are connected to one end of the switch K45, the other ends of the switches K6 and K7 are connected to one end of the switch K67, and the other ends of the switches K45 and K67 are connected to one end of the switch K47; The other end of the switch K47 is connected to the other end of the switch K04; The first resistor string module includes a switch K0, a switch K1, a switch K2, a switch K3, a switch K01, a switch K23, and a resistor R11, a resistor R12, a resistor R13 and a resistor R14 connected in series in sequence; The control ends of the switches K0, K1, K2, K3, K01 and K23 are used as digital ends of the first resistor string module, and are used to receive external digital input signals respectively; One end of the resistor R11 and the resistor R12 are connected to one end of the switch K0, the other end of the resistor R11 is grounded, the other end of the resistor R12 and one end of the resistor R13 are connected to one end of the switch K1, and the other ends of the switch K0 and the switch K1 are connected to one end of the switch K01; one end of the resistor R14 is connected to one end of the switch K3, the other ends of the resistor R14 and the resistor R13 are connected to one end of the switch K2, and the other ends of the switch K2 and the switch K3 are connected to one end of the switch K23; the other ends of the switch K01 and the switch K23 are connected to the output end of the reference current injection module Iref; The reference current injection module Iref includes a MOS tube M1, a MOS tube M2, a MOS tube M3, a resistor R30, and an operational amplifier OP; The non-inverting input terminal of the operational amplifier OP is used to connect to the external reference voltage Vref2, the inverting input terminal is connected to the source of the MOS tube M1, the source of the MOS tube M1 is grounded through the resistor R30, the gate of the MOS tube M1 is connected to the output terminal of the operational amplifier OP, the drain of the MOS tube M1 is connected to the drain of the MOS tube M2, the gate and the drain of the MOS tube M2 are short-circuited, the gate of the MOS tube M2 is connected to the gate of the MOS tube M3, the sources of the MOS tubes M2 and M3 are both used to connect to the external voltage VDD, the drain of the MOS tube M3 is used as the output terminal of the reference current injection module Iref, and is connected to the input terminal of the first resistor string module and one end of the resistor R15; The error amplification module includes an error amplifier EA and a compensation network; The non-inverting input terminal of the error amplifier is connected to the reference voltage Vref, the inverting input terminal is connected to the FB terminal, and the output terminal of the error amplifier is fed back to the inverting input terminal thereof through a compensation network.

4. A current injection hybrid DAC conversion method with a wide output voltage range, based on the current injection hybrid DAC converter with a wide output voltage range as claimed in claim 3, characterized in that: The following steps are involved: When the required output voltage V out When it is less than or equal to 0.6V; Step 1: Output voltage V as required out Size, edit the corresponding digital input signal; Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the first resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref, the first resistor string module and the voltage adjustment module according to the digital signal to be connected, and the voltage adjustment module controls the second resistor string module to be disconnected according to the digital signal; Step 3: outputting a reference current through a reference current injection module Iref, and then shunting the reference current through a first resistor string module and a control module; Step 4: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module; Step 5: Use the voltage adjustment module to divide the voltage at the FB terminal to obtain the output voltage V out ; When the required output voltage V out When greater than 0.6V: Step 1: Output voltage V as required out Size, edit the corresponding digital input signal; Step 2, sending the edited digital input signal to the first resistor string module, the second resistor string module, the control module and the voltage adjustment module, the second resistor string module adjusts its resistance value according to the digital input signal, the control module adjusts the reference current injection module Iref according to the digital signal, and the first resistor string module and the voltage adjustment module are disconnected, and the voltage adjustment module controls the second resistor string module to be connected according to the digital signal; Step 3: Adjust the voltage at the FB terminal to be equal to the reference voltage Vref through the error amplification module; Step 4: The voltage at the FB terminal is boosted for the first time by the voltage adjustment module and output to the second resistor string module; Step 5: The voltage at the FB terminal is boosted multiple times through the second resistor string module to obtain the required output voltage V out .

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