Low-power-consumption constant-voltage constant-current circuit based on VIOC

Abstract

The invention provides a VIOC-based low-power-consumption constant-voltage constant-current circuit. A VIOC differential acquisition module is used for acquiring the difference value between the output voltage of a DCDC switching power supply and the output voltage of an LDO module; the LDO feedback module is used for feeding back the voltage output by the LDO module to the LDO module, or converting the current output by the LDO module into a corresponding voltage signal and feeding back the voltage signal to the LDO module; the voltage and current monitoring module is used for measuring the voltage and current of the direct current output by the LDO module and outputting a digital communication signal and a fault protection interrupt signal to the MCU module according to the measured voltage and current; the MCU module is used for adjusting the output voltage of the LDO module according to the digital communication signal and the interrupt signal of fault protection. According to the invention, constant-voltage and constant-current real-time switching of positive and negative voltage power supply in an OLED CELL test is satisfied.

Description

Technical Field

[0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a low-power consumption constant voltage and constant current circuit based on VIOC. Background Art

[0002] In the screen display industry, as the market share of OLED screens gradually increases and the scope of application gradually expands, the testing of OLED screen CELL processes has become more comprehensive and strict. If the OLED screen needs to be lit, in addition to the necessary small signal, it also requires +VDD and -VSS two-way power level positive and negative voltage power supply. In order to meet the needs of different products, +VDD and -VSS have two different combinations in output type. One is a combination of constant voltage source and constant voltage source, that is, +VDD and -VSS are both constant voltage sources; the other is a combination of constant voltage source and constant current source, that is, one of +VDD and -VSS is a constant voltage source and the other is a constant current source. According to the needs of display manufacturers, there will be a real-time change in the output type during the actual lighting process.

[0003] In order to take into account the requirements of low ripple and low power consumption, the common practice in engineering is to use a DCDC switching power supply and a discrete LDO linear regulator in series. DCDC and LDO are controlled by independent DACs respectively. In the power-on sequence, the DCDC power output is turned on first. At this time, the LDO module is still in the off state. Since the two modules are connected in series, the entire system has no voltage output at this time. When the DCDC reaches the rated output voltage, the LDO module is turned on according to the instruction of the master control, and the system voltage or current begins to output. Note that DCDC always outputs in the mode of a constant voltage source, while LDO can output in the mode of a constant voltage source or a constant current source.

[0004] In the switching of LDO constant voltage and constant current output types, it is mainly digital switching based on ADC (analog-to-digital converter) sampling. In order to reduce the calculation amount of the main control unit and the complexity of the hardware circuit, this method actually adopts a digitally controlled pseudo-constant current mode. This mode is essentially still a constant voltage source, the difference is that the ADC is used to collect the output voltage and current at the same time. The normal working state is a constant voltage source. When it is necessary to switch from a constant voltage source to a constant current source, the working steps of the main control microprocessor are: ① In the constant voltage source mode, read the load current. ② Calculate the load impedance based on the output voltage and load current. ③ Use the load impedance as the proportional coefficient of PID control, and the main control calculates and outputs the new set voltage. ④ Monitor the output current of the LDO module. If there is an error with the set value, continue to iterate and adjust, and finally achieve the purpose of constant current. The reason why it is called a pseudo-constant current mode is that for cost considerations, in the screen test industry, the voltage and current sampling ADC generally adopts a general low-speed ADC or even only a current monitoring chip integrated with ADC, which cannot achieve fast sampling and adjustment. The main disadvantages are: ① The adjustment time is long. A single adjustment takes tens of milliseconds, and if multiple iterations are required, the adjustment time may be as high as hundreds of milliseconds. ② Voltage shock. The essence of the adjustment is to adjust the DAC module of DCDC and LDO. If the actual value differs too much from the set value and the algorithm is not well optimized, the single adjustment step may be too large, which will cause a sudden step change in the voltage and an uneven waveform, which may have adverse effects on the equipment or product. Summary of the invention

[0005] The present invention aims at the deficiencies in the prior art and provides a low-power consumption constant voltage and constant current circuit based on VIOC.

[0006] The present invention provides a low-power consumption constant voltage and constant current circuit based on VIOC, comprising: a DCDC switching power supply, an LDO module, a VIOC differential acquisition module, an LDO feedback module, a voltage and current monitoring module and an MCU module;

[0007] The DCDC switching power supply is used to convert the input voltage to a first target DC voltage and output it to the LDO module;

[0008] The LDO module is used to suppress the ripple and noise of the direct current output by the DCDC switching power supply, and output a second target direct current voltage to the LDO feedback module;

[0009] The VIOC differential acquisition module is used to collect the difference between the output voltage of the DCDC switching power supply and the output voltage of the LDO module, and transmit the difference to the DCDC switching power supply;

[0010] The LDO feedback module is used to feed back the voltage output by the LDO module and output it into the LDO module, or to convert the current output by the LDO module into a corresponding voltage signal and then feed it back and output it into the LDO module, and output it as a constant current source or a constant voltage source;

[0011] The voltage and current monitoring module is used to measure the voltage and current of the DC power output by the LDO module, and output a digital communication signal and a fault protection interrupt signal to the MCU module according to the measured voltage and current;

[0012] The MCU module is used to adjust the output voltage of the LDO module according to the digital communication signal and the interrupt signal of the fault protection.

[0013] Optionally, the LDO module includes a MOS tube and a first comparator;

[0014] The source of the MOS tube is electrically connected to the output end of the DCDC switching power supply and the first input end of the VIOC differential acquisition module, the drain is electrically connected to the input end of the LDO feedback module and the second input end of the VIOC differential acquisition module, and the gate is electrically connected to the output end of the first comparator;

[0015] The first input terminal of the first comparator is electrically connected to the output terminal of the MCU module, and the second input terminal of the first comparator is electrically connected to the output terminal of the LDO feedback module.

[0016] Optionally, the VIOC differential acquisition module includes a first operational amplifier, a fifth resistor and a sixth resistor;

[0017] The first input end of the first operational amplifier is electrically connected to the output end of the DCDC switching power supply, and the second input end is electrically connected to the drain of the MOS tube; the output end of the first operational amplifier is electrically connected to one end of the fifth resistor; one end of the fifth resistor away from the first operational amplifier is electrically connected to the FB pin of the DCDC switching power supply and one end of the sixth resistor; one end of the sixth resistor away from the fifth resistor is grounded.

[0018] Optionally, the LDO feedback module includes a first resistor, a second comparator, a multiplexer, a second operational amplifier, a second resistor and a third resistor;

[0019] One end of the first resistor is electrically connected to the drain of the MOS tube and the first input end of the second comparator, and one end away from the MOS tube is electrically connected to the second input end of the second comparator and the first input end of the second operational amplifier; the output end of the second comparator is electrically connected to the first input end of the multiplexer; the second input end of the second operational amplifier is electrically connected to the output end of the second operational amplifier; the output end of the second operational amplifier is electrically connected to one end of the second resistor; one end of the second resistor away from the second operational amplifier is electrically connected to the second input end of the multiplexer and one end of the third resistor; one end of the third resistor away from the second resistor is grounded; the output end of the multiplexer is electrically connected to the second input end of the first comparator.

[0020] Optionally, the voltage and current monitoring module includes a fourth resistor, a third comparator and a monitoring chip;

[0021] One end of the fourth resistor is electrically connected to one end of the first resistor away from the MOS tube and the first input end of the third comparator; one end of the fourth resistor away from the first resistor is electrically connected to the second input end of the third comparator and the first input end of the monitoring chip; the output end of the third comparator is electrically connected to the second input end of the monitoring chip; the output end of the monitoring chip is electrically connected to the input end of the MCU module.

[0022] Optionally, the first output end of the MCU module is electrically connected to the third input end of the multiplexer; the second output end of the MCU module is electrically connected to the input end of a subsequent-stage digital-to-analog conversion module; and the output end of the subsequent-stage digital-to-analog conversion module is electrically connected to the first input end of the first comparator.

[0023] Optionally, the voltage difference V1 of the LDO module is calculated according to the following formula:

[0024] V1=V fb ×(R5+R6) / R6;

[0025] Among them, V fb is the internal reference voltage of the DCDC switching power supply chip; R5 is the resistance value of the fifth resistor; R6 is the resistance value of the sixth resistor.

[0026] Optionally, the output voltage V of the DCDC switching power supply can be calculated according to the following formula: dc :

[0027] V dc =V fb ×(R5+R6) / R6+V2;

[0028] Among them, V fbis the internal reference voltage of the DCDC switching power supply chip; R5 is the resistance value of the fifth resistor; R6 is the resistance value of the sixth resistor; V2 is the output voltage of the LDO module.

[0029] Optionally, the MOS transistor is a P-channel metal oxide semiconductor (PMOS) transistor.

[0030] Beneficial effects:

[0031] 1. Able to meet the real-time switching of constant voltage and constant current of positive and negative voltage power supply in OLED CELL test;

[0032] 2. The hardware feedback loop switching time is short, which can improve the OLED CELL test speed;

[0033] 3. Hardware feedback loop switching can ensure smooth output waveform and small current impact;

[0034] 4. In the case of unknown load, the output voltage of the DCDC switching power supply can be automatically adjusted according to the output voltage of the LDO module, reducing additional software operations;

[0035] 5. The output voltage of the DCDC switching power supply can maintain a fixed LDO voltage drop during the switching process through feedback, minimizing heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A structural schematic diagram of a low-power consumption constant voltage and constant current circuit based on VIOC provided by an embodiment of the present invention;

[0038] Figure 2 A circuit diagram of a low-power consumption constant voltage and constant current circuit based on VIOC provided in an embodiment of the present invention;

[0039] Figure 3 A circuit diagram of an LDO feedback module provided by an embodiment of the present invention;

[0040] Figure 4 A circuit diagram of a VIOC differential acquisition module provided in an embodiment of the present invention;

[0041] Figure 5 A circuit diagram of an LDO module provided by an embodiment of the present invention;

[0042] Figure 6A circuit diagram of a voltage and current monitoring module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1 and Figure 2 As shown, this embodiment provides a low-power constant voltage and constant current circuit based on VIOC, including a DCDC switching power supply 1, an LDO module 2, a VIOC differential acquisition module 3, an LDO feedback module 4, a voltage and current monitoring module 5 and an MCU module 6.

[0046] The DCDC switching power supply 1 is used to convert the input voltage into a first target DC voltage and output it to the LDO module.

[0047] The DCDC switching power supply 1 efficiently converts the input voltage of the device into a suitable set voltage. Specifically, the DCDC output voltage = LDO output voltage + drop out voltage. Its essence is a DC constant voltage source. The input is the system voltage, and the output is a specific voltage power supply after the system voltage power supply is stepped down. The DCDC DC output ripple and noise are relatively large, which will affect the test accuracy for display test equipment, so the LDO module needs to be used in the later stage to further suppress ripple and noise.

[0048] Drop out voltage usually refers to the minimum value of the output voltage in a power converter or regulator when the load current passes through it. This phenomenon is particularly common in low-dropout linear regulators (LDOs), because LDOs need to maintain a certain voltage difference at the output to ensure that the internal adjustment components (such as transistors) can work properly.

[0049] In LDO, drop out voltage refers to the minimum voltage difference between the output voltage and the input voltage at the minimum load current. For example, if the drop out voltage of an LDO is 0.3V, when the output voltage is 3.0V, the input voltage should be at least 3.3V (3.0V+0.3V). If the input voltage is lower than this value, the LDO may not be able to maintain its output voltage, causing the output voltage to drop, which may affect the normal operation of the electronic equipment connected to the LDO output.

[0050] The LDO module 2 is used to suppress the ripple and noise of the direct current output by the DCDC switching power supply 1 , and output a second target direct current voltage to the LDO feedback module 4 .

[0051] like Figure 5 As shown, the LDO module 2 includes a MOS tube Q1 and a first comparator U1; the source of the MOS tube Q1 is electrically connected to the output end of the DCDC switching power supply 1 and the first input end of the VIOC differential acquisition module 3, the drain is electrically connected to the input end of the LDO feedback module 4 and the second input end of the VIOC differential acquisition module 3, and the gate is electrically connected to the output end of the first comparator U1.

[0052] A first input terminal of the first comparator U1 is electrically connected to an output terminal of the MCU module 6 , and a second input terminal of the first comparator U1 is electrically connected to an output terminal of the LDO feedback module 4 .

[0053] The LDO module 2 is a low dropout regulator. The core of the LDO module 2 is composed of a first comparator U1 (i.e., an error comparator) and a high-power MOS tube Q1 (for a positive voltage circuit, the MOS tube Q1 is generally a P-MOSFET device, i.e., a P-channel metal oxide semiconductor PMOS transistor). The function of the error comparator is to compare the feedback of the output load with the set DAC voltage, and by adjusting the gate voltage of the MOS tube Q1, the MOS tube Q1 is made to work in the variable resistance area, so as to achieve the purpose of outputting a specific voltage and suppressing the DC ripple output by the DCDC switching power supply 1, and finally obtain a DC with relatively low ripple and noise levels to meet the power demand of the screen to be tested. The input of the LDO module 2 is the output of the DCDC switching power supply 1, and the output is a specific voltage power supply after ripple suppression.

[0054] The VIOC differential acquisition module 3 is used to collect the difference between the output voltage of the DCDC switching power supply 1 and the output voltage of the LDO module 2, and transmit the difference to the DCDC switching power supply 1.

[0055] like Figure 4 As shown, the VIOC differential acquisition module 3 includes a first operational amplifier U2, a fifth resistor R5 and a sixth resistor R6.

[0056] The first input end of the first operational amplifier U2 is electrically connected to the output end of the DCDC switching power supply 1, and the second input end is electrically connected to the drain of the MOS tube Q1; the output end of the first operational amplifier U2 is electrically connected to one end of the fifth resistor R5; one end of the fifth resistor R5 away from the first operational amplifier U2 is electrically connected to the FB pin of the DCDC switching power supply 1 and one end of the sixth resistor R6; one end of the sixth resistor R6 away from the fifth resistor R5 is grounded.

[0057] The inputs of VIOC differential acquisition module 3 are the output voltage of DCDC switching power supply 1 and the output voltage of LDO module 2, and the output of VIOC differential acquisition module 3 is the difference between the input voltages. The main function of VIOC differential acquisition module 3 is to collect the front and rear end voltages of MOS tube Q1, and after differential operation, transmit the difference to the front-stage switching power supply voltage regulation module. R5 and R6 are both voltage-dividing resistors. According to the calculation of VIOC differential acquisition module 3, the voltage difference V1 of LDO module 2 can be obtained:

[0058] V1=V fb ×(R5+R6) / R6.

[0059] Among them, V fb is the internal reference voltage of the DCDC switching power supply chip; R5 is the resistance value of the fifth resistor; R6 is the resistance value of the sixth resistor.

[0060] For the convenience of design, the differential result can also be directly output to the FB pin of the DCDC switching power supply 1. Through this differential feedback, without the need for a pre-stage DAC (pre-stage digital-to-analog converter), it can be ensured that the pre-stage DCDC output voltage is always at least one reference value of the internal FB of the switching power supply (generally, the internal FB of the chip is 0.6V or 0.8V) higher than the output voltage of the LDO module 2.

[0061] The voltage regulation of the front-stage DCDC is controlled by the VIOC differential acquisition module 3. For automatic regulation, the output voltage V dc :

[0062] V dc =V fb ×(R5+R6) / R6+V2.

[0063] Among them, V2 is the output voltage of the LDO module. Therefore, the voltage drop loss of the LDO module 2 can be guaranteed to be constant, and the thermal breakdown of the MOS tube Q1 can be prevented.

[0064] The LDO feedback module 4 is used to feed back the voltage output by the LDO module 2 into the LDO module, or to convert the current output by the LDO module into a corresponding voltage signal and then feed it back into the LDO module 2, and output it as a constant current source or a constant voltage source.

[0065] like Figure 3 As shown, the LDO feedback module includes a first resistor R1, a second comparator U3, a multiplexer, a second operational amplifier U4, a second resistor R2 and a third resistor R3. In this embodiment, the model of the multiplexer is TS5A23160.

[0066] One end of the first resistor R1 is electrically connected to the drain of the MOS transistor Q1 and the first input end of the second comparator U3, and the end away from the MOS transistor Q1 is electrically connected to the second input end of the second comparator U3 and the first input end of the second operational amplifier U4; the output end of the second comparator U3 is electrically connected to the first input end of the multiplexer; the second input end of the second operational amplifier U4 is electrically connected to the output end of the second operational amplifier U4; the output end of the second operational amplifier U4 is electrically connected to one end of the second resistor R2; one end of the second resistor R2 away from the second operational amplifier U4 is electrically connected to the second input end of the multiplexer and one end of the third resistor R3; one end of the third resistor R3 away from the second resistor R2 is grounded; the output end of the multiplexer is electrically connected to the second input end of the first comparator U1.

[0067] The inputs of the LDO feedback module 4 are the output voltage and output current of the LDO module 2, respectively, and the output of the LDO feedback module 4 is a voltage signal. The feedback of the LDO is composed of high-side current feedback and remote voltage feedback, wherein the output current of the LDO module 2 is converted into a corresponding voltage signal via the first resistor R1 (sampling resistor). The loop switching of the LDO feedback module 4 is completed by controlling the multiplexer through the MCU module 6. The feedback output enters the LDO module 2, is compared with the DAC configured by the MCU module 6, and then controls the MOS tube Q1, which can be output as a constant current source or a constant voltage source.

[0068] The second operational amplifier U4 is mainly used for impedance transformation. The high input impedance of the operational amplifier is used to reduce the leakage current caused by directly using resistor voltage divider feedback. The second resistor R2 and the third resistor R3 are both voltage divider resistors. The voltage divider resistors are placed at the output stage of the second operational amplifier U4 (instrumentation amplifier). The function is to extract the feedback signal and send it to the LDO module 2 through the multiplexer to perform error amplification with the DAC voltage, thereby controlling the gate of the MOS tube Q1.

[0069] The voltage and current monitoring module 5 is used to measure the voltage and current of the DC power output by the LDO module 2, and output a digital communication signal and a fault protection interrupt signal to the MCU module 6 according to the measured voltage and current.

[0070] like Figure 6 As shown, the voltage and current monitoring module 5 includes a fourth resistor R4, a third comparator U5 and a monitoring chip; in this embodiment, the model of the monitoring chip is INA226.

[0071] One end of the fourth resistor R4 is electrically connected to one end of the first resistor R1 away from the MOS tube Q1 and the first input end of the third comparator U5; one end of the fourth resistor R4 away from the first resistor R1 is electrically connected to the second input end of the third comparator U5 and the first input end of the monitoring chip; the output end of the third comparator U5 is electrically connected to the second input end of the monitoring chip; the output end of the monitoring chip is electrically connected to the input end of the MCU module 6.

[0072] The voltage and current monitoring module 5 is mainly composed of a voltage and current monitoring chip and a current sampling resistor (the fourth resistor R4), and its function is to measure the voltage and current of the DC output of the LDO module 2. The measured data is used as digital feedback on the one hand to adjust the output voltage in real time to ensure output accuracy, and on the other hand to protect against overvoltage and overcurrent and monitor circuit failures. The input is low ripple DC, and the output is a digital communication signal and an interrupt signal for fault protection.

[0073] The MCU module 6 is used to adjust the output voltage of the LDO module 2 according to the digital communication signal and the interrupt signal of the fault protection.

[0074] The MCU module 6 is mainly composed of a microprocessor chip, and its function is to receive measurement values, perform feedback calculations, set output voltages, and process various circuit protections. The input is the communication data and protection interrupts output by the voltage and current monitoring module 5, and the output loop switching signal is sent to the multiplexer and the output digital SPI signal is sent to the DAC for data communication.

[0075] The present embodiment provides a low-power consumption constant voltage and constant current circuit based on VIOC, which can meet the real-time switching of constant voltage and constant current of positive and negative voltage power supply in OLED CELL test; the hardware feedback loop switching time is short, which can improve the OLED CELL test speed; the hardware feedback loop switching can ensure the smoothness of the output waveform and the current impact is relatively small; in the case of unknown load, the output voltage of the DCDC switching power supply can be adjusted according to the voltage output by the LDO module, reducing additional software operations; the output voltage of the DCDC switching power supply can maintain a fixed LDO voltage drop during the switching process through feedback, thereby minimizing heat dissipation.

[0076] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A low-power constant voltage and constant current circuit based on VIOC, characterized in that: include: DCDC switching power supply, LDO module, VIOC differential acquisition module, LDO feedback module, voltage and current monitoring module and MCU module; The DCDC switching power supply is used to convert the input voltage to a first target DC voltage and output it to the LDO module; The LDO module is used to suppress the ripple and noise of the direct current output by the DCDC switching power supply, and output a second target direct current voltage to the LDO feedback module; The VIOC differential acquisition module is used to collect the difference between the output voltage of the DCDC switching power supply and the output voltage of the LDO module, and transmit the difference to the DCDC switching power supply; The LDO feedback module is used to feed back the voltage output by the LDO module and output it into the LDO module, or to convert the current output by the LDO module into a corresponding voltage signal and then feed it back and output it into the LDO module, and output it as a constant current source or a constant voltage source; The voltage and current monitoring module is used to measure the voltage and current of the DC power output by the LDO module, and output a digital communication signal and a fault protection interrupt signal to the MCU module according to the measured voltage and current; The MCU module is used to adjust the output voltage of the LDO module according to the digital communication signal and the interrupt signal of the fault protection.

2. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 1, characterized in that: The LDO module includes a MOS tube and a first comparator; The source of the MOS tube is electrically connected to the output end of the DCDC switching power supply and the first input end of the VIOC differential acquisition module, the drain is electrically connected to the input end of the LDO feedback module and the second input end of the VIOC differential acquisition module, and the gate is electrically connected to the output end of the first comparator; The first input terminal of the first comparator is electrically connected to the output terminal of the MCU module, and the second input terminal of the first comparator is electrically connected to the output terminal of the LDO feedback module.

3. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 2, characterized in that: The VIOC differential acquisition module includes a first operational amplifier, a fifth resistor and a sixth resistor; The first input end of the first operational amplifier is electrically connected to the output end of the DCDC switching power supply, and the second input end is electrically connected to the drain of the MOS tube; the output end of the first operational amplifier is electrically connected to one end of the fifth resistor; one end of the fifth resistor away from the first operational amplifier is electrically connected to the FB pin of the DCDC switching power supply and one end of the sixth resistor; one end of the sixth resistor away from the fifth resistor is grounded.

4. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 2, characterized in that: The LDO feedback module includes a first resistor, a second comparator, a multiplexer, a second operational amplifier, a second resistor and a third resistor; One end of the first resistor is electrically connected to the drain of the MOS tube and the first input end of the second comparator, and one end away from the MOS tube is electrically connected to the second input end of the second comparator and the first input end of the second operational amplifier; the output end of the second comparator is electrically connected to the first input end of the multiplexer; the second input end of the second operational amplifier is electrically connected to the output end of the second operational amplifier; the output end of the second operational amplifier is electrically connected to one end of the second resistor; one end of the second resistor away from the second operational amplifier is electrically connected to the second input end of the multiplexer and one end of the third resistor; one end of the third resistor away from the second resistor is grounded; the output end of the multiplexer is electrically connected to the second input end of the first comparator.

5. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 4, characterized in that: The voltage and current monitoring module includes a fourth resistor, a third comparator and a monitoring chip; One end of the fourth resistor is electrically connected to one end of the first resistor away from the MOS tube and the first input end of the third comparator; one end of the fourth resistor away from the first resistor is electrically connected to the second input end of the third comparator and the first input end of the monitoring chip; the output end of the third comparator is electrically connected to the second input end of the monitoring chip; the output end of the monitoring chip is electrically connected to the input end of the MCU module.

6. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 4, characterized in that: The first output end of the MCU module is electrically connected to the third input end of the multiplexer; the second output end of the MCU module is electrically connected to the input end of the subsequent digital-to-analog conversion module; and the output end of the subsequent digital-to-analog conversion module is electrically connected to the first input end of the first comparator.

7. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 3, characterized in that: The voltage drop V1 of the LDO module is calculated according to the following formula: V1=V fb ×(R5+R6) / R6; Among them, V fb is the internal reference voltage of the DCDC switching power supply chip; R5 is the resistance value of the fifth resistor; R6 is the resistance value of the sixth resistor.

8. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 3, characterized in that: Calculate the output voltage V of the DCDC switching power supply according to the following formula dc : <h2 style=";text-align:left;direction:ltr">V<h2 style=";text-align:left;direction:ltr"> dc <h2 style=";text-align:left;direction:ltr"> =V<h2 style=";text-align:left;direction:ltr"> fb <h2 style=";text-align:left;direction:ltr"> ×(R5+R6) / R6+V2; Among them, V fb is the internal reference voltage of the DCDC switching power supply chip; R5 is the resistance value of the fifth resistor; R6 is the resistance value of the sixth resistor; V2 is the output voltage of the LDO module.

9. The low-power consumption constant voltage and constant current circuit based on VIOC according to claim 2, characterized in that: The MOS tube is a P-channel metal oxide semiconductor (PMOS) transistor.

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