A boost circuit with software adjustable output voltage

Abstract

The application relates to a BOOST circuit with software-adjustable output voltage, comprising: a master control chip for outputting a first PWM signal according to a set voltage value and controlling the switching tube to alternately conduct and turn off during initial starting; a BOOST power module for reciprocating energy storage and energy release; an output voltage feedback module for dividing the output voltage of the BOOST power module to obtain a feedback voltage; an overvoltage protection module for outputting a low level when the feedback voltage is greater than an upper threshold value or outputting a high level when the feedback voltage is less than a lower threshold value and acting on the switching tube through a second diode; and the master control chip is further used for outputting a second PWM signal with fixed duty ratio and acting on the control electrode of the switching tube when the overvoltage protection module outputs the low level. After the output voltage of the BOOST circuit reaches the set value, only one PWM signal with fixed duty ratio needs to be output, the rest functions are completed by the hardware circuit, the flexibility is relatively high, and a large amount of master control chip operation amount can be saved.

Description

Technical Field

[0001] This invention relates to the field of power supply circuits, and more specifically to a BOOST circuit with software-adjustable output voltage. Background Technology

[0002] Boost circuits are a common type of voltage boosting circuit in electronic products. Most chip manufacturers now offer fully integrated chips with only a few external inductors and resistors / capacitors to achieve the desired functionality. However, integrated chips are expensive, and their output voltage is regulated by a resistor feedback network. Changing the output voltage only changes the resistance of the feedback network, limiting their adaptability. To ensure continuously adjustable output voltage, most systems use a main control chip to collect the voltage value from the resistor feedback network in real time. Based on this collected voltage value, the duty cycle of the PWM signal controlling the switching transistor is adjusted accordingly to regulate the output voltage. However, this method involves a large computational load and consumes a significant amount of internal resources of the main control chip. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a BOOST circuit with software adjustable output voltage, which can reduce the amount of computation of the main control chip.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a BOOST circuit with software adjustable output voltage, including a main control chip, a BOOST power supply module, an output voltage feedback module and an overvoltage protection module;

[0005] The main control chip is used to adjust the duty cycle of the first control signal according to the set voltage value during initial startup to obtain the first PWM signal, and output it through the first control signal port. It also acts on the control electrode of the switching transistor Q in the BOOST power module to control the switching transistor Q to alternately turn on and off.

[0006] The BOOST power module is used to repeatedly store and release energy when the switching transistor Q is alternately turned on and off, until the output voltage of the BOOST power module is higher than the input voltage.

[0007] The output voltage feedback module is used to divide the output voltage of the BOOST power module to obtain the feedback voltage V2;

[0008] The overvoltage protection module is used to generate a threshold reference voltage V1 and simultaneously acquire the feedback voltage V2. When the feedback voltage V2 is greater than the upper threshold value of the threshold reference voltage V1, it outputs a low level to control the switch Q to turn off, or when the feedback voltage V2 is less than the lower threshold value of the threshold reference voltage V1, it outputs a high level to control the switch Q to turn on, and acts on the control electrode of the switch Q through the second diode D2.

[0009] The main control chip is also used to adjust the first control signal to a second PWM signal with a fixed duty cycle when the overvoltage protection module outputs a low level, and output it through the first control signal port, and act on the control electrode of the switching transistor Q;

[0010] The BOOST power module is also used to output a stable voltage under the combined effect of the low level output by the overvoltage protection module and the second PWM signal with a fixed duty cycle output by the main control chip;

[0011] The BOOST power module is also used to output a stable voltage under the combined effect of the high level output by the overvoltage protection module and the first PWM signal output by the main control chip.

[0012] The beneficial effects of this invention are as follows: In the software-adjustable BOOST circuit of this invention, the output voltage value of the BOOST circuit can be set by the resistor feedback network or by the main control chip. At the same time, only in the initial stage of circuit startup does the main control chip need to adjust the output duty cycle according to the feedback voltage. After the output voltage reaches the set value, it only needs to output a PWM signal with a fixed duty cycle. The remaining functions are completed by the hardware circuit, which is highly flexible and can save a lot of the main control chip's computing power and resources. Attached Figure Description

[0013] Figure 1 This is an overall structural block diagram of a software-adjustable BOOST circuit for output voltage according to Embodiment 1 of the present invention;

[0014] Figure 2 This is an overall structural block diagram of a software-adjustable BOOST circuit for output voltage according to Embodiment 2 of the present invention;

[0015] Figure 3 This is an overall structural block diagram of a software-adjustable BOOST circuit for output voltage according to Embodiment 3 of the present invention;

[0016] Figure 4 This is a block diagram of a software-adjustable BOOST circuit for output voltage according to the present invention.

[0017] Figure 5 This is a circuit diagram of a software-adjustable BOOST circuit for output voltage according to the present invention. Detailed Implementation

[0018] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0019] Example 1:

[0020] like Figure 1 As shown, a BOOST circuit with software adjustable output voltage includes a main control chip, a BOOST power module, an output voltage feedback module, and an overvoltage protection module.

[0021] The main control chip is used to adjust the duty cycle of the first control signal according to the set voltage value during initial startup to obtain the first PWM signal, and output it through the first control signal port. It also acts on the control electrode of the switching transistor Q in the BOOST power module to control the switching transistor Q to alternately turn on and off.

[0022] The BOOST power module is used to repeatedly store and release energy when the switching transistor Q is alternately turned on and off, until the output voltage of the BOOST power module is higher than the input voltage.

[0023] The output voltage feedback module is used to divide the output voltage of the BOOST power module to obtain the feedback voltage V2;

[0024] The overvoltage protection module is used to generate a threshold reference voltage V1 (the threshold reference voltage V1 is also called the overvoltage protection reference voltage V1), and simultaneously acquire the feedback voltage V2. When the feedback voltage V2 is greater than the upper threshold value of the threshold reference voltage V1, it outputs a low level to control the switch Q to turn off, or outputs a high level to control the switch Q to turn on when the feedback voltage V2 is less than the lower threshold value of the threshold reference voltage V1, and acts on the control electrode of the switch Q through the second diode D2.

[0025] The main control chip is also used to adjust the first control signal to a second PWM signal with a fixed duty cycle when the overvoltage protection module outputs a low level, and output it through the first control signal port, and act on the control electrode of the switching transistor Q;

[0026] The BOOST power module is also used to output a stable voltage under the combined effect of the low level output by the overvoltage protection module and the second PWM signal with a fixed duty cycle output by the main control chip;

[0027] The BOOST power module is also used to output a stable voltage under the combined effect of the high level output by the overvoltage protection module and the first PWM signal output by the main control chip.

[0028] Example 2:

[0029] In the BOOST power module, the switching transistor Q is connected in series with a sampling resistor R, and the current flowing through the switching transistor Q is the same as the current flowing through the sampling resistor R; for example Figure 2 As shown, the BOOST circuit also includes an overcurrent protection module;

[0030] The overcurrent protection module generates a threshold reference voltage V3 (also known as an overcurrent protection reference voltage V3), and simultaneously acquires the voltage between the switch Q and the sampling resistor R to obtain a sampling voltage V4. When the sampling voltage V4 is greater than the upper threshold value of the threshold reference voltage V3, it outputs a low level to control the switch Q to turn off, or when the sampling voltage V4 is less than the lower threshold value of the threshold reference voltage V3, it outputs a high level to control the switch Q to turn on. The overcurrent protection is achieved by applying a third diode D3 to the control electrode of the switch Q.

[0031] Example 3:

[0032] In this specific embodiment: the main control chip is also used to acquire the feedback voltage V2, calculate the output voltage of the BOOST power module based on the feedback voltage V2, and adjust the duty cycle of the second control signal according to the calculated output voltage of the BOOST power module to obtain a third PWM signal, which is then output through the second control signal port; for example... Figure 3 As shown, the BOOST circuit also includes a programmable overvoltage protection module;

[0033] The programmable overvoltage protection module is used to convert the third PWM signal output by the main control chip into a stable DC voltage and apply it to the threshold reference voltage V1 of the overvoltage protection module, thereby changing the threshold reference voltage V1 of the overvoltage protection module.

[0034] The overvoltage protection module is also used to change the output voltage of the BOOST power module when the threshold reference voltage V1 changes.

[0035] Figure 4 This is a block diagram of a software-adjustable BOOST circuit for output voltage according to the present invention; wherein:

[0036] The overvoltage protection module includes a threshold reference voltage V1 generation sub-circuit, a first hysteresis comparator, and a first low-pass filter sub-circuit. The threshold reference voltage V1 generation sub-circuit is connected to the non-inverting input of the first hysteresis comparator. The inverting input of the first hysteresis comparator is connected to the feedback voltage V2 through the first low-pass filter sub-circuit. The output of the first hysteresis comparator is connected to the digital signal acquisition port of the main control chip. The output of the first hysteresis comparator is also connected to the control electrode of the switching transistor Q through the second diode D2.

[0037] The overcurrent protection module includes a threshold reference voltage V3 generation sub-circuit, a second hysteresis comparator, and a second low-pass filter sub-circuit. The threshold reference voltage V3 generation sub-circuit is connected to the non-inverting input terminal of the second hysteresis comparator. The inverting input terminal of the second hysteresis comparator is connected to the sampling voltage V4 through the second low-pass filter sub-circuit. The output terminal of the second hysteresis comparator is connected to the control electrode of the switching transistor through the third diode D3.

[0038] The programmable overvoltage protection module includes a second-order active filter and a third low-pass filter sub-circuit; the main control chip is connected to the feedback voltage V2 through the third low-pass filter sub-circuit, and the second control signal port of the main control chip acts on the threshold reference voltage V1 generated by the overvoltage protection module through the second-order active filter.

[0039] Figure 5 This is a circuit schematic diagram of a software-adjustable BOOST circuit for output voltage according to the present invention; wherein:

[0040] The BOOST power module includes an inductor L, a first capacitor C1, a second capacitor C2, a first diode D1, a switching transistor Q, and a sampling resistor R. One end of the inductor L is the input terminal of the BOOST power module and is used to connect to an external power supply. One end of the inductor L is also grounded through the capacitor C1. The other end of the inductor L is connected to the positive terminal of the first diode D1 and the drain of the switching transistor Q. The negative terminal of the first diode D1 is grounded through the second capacitor C2, and the negative terminal of the first diode D1 is the output terminal of the BOOST power module. The source of the switching transistor Q is grounded through the sampling resistor R, and the gate of the switching transistor Q is connected to the first control signal port of the main control chip through the fifteenth resistor R15. The gate of the switching transistor Q is the control terminal of the switching transistor Q, and the voltage between the source of the switching transistor Q and the sampling resistor R is the sampling voltage V4.

[0041] Specifically, the first capacitor C1 is a filter capacitor. The control electrode of the switching transistor Q requires an input drive signal to control its conduction and cutoff, which is usually provided by an integrated switching power supply chip.

[0042] The output voltage feedback module includes a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the output terminal of the BOOST power module, the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded; wherein, the voltage between the first resistor R1 and the second resistor R2 is the feedback voltage V2.

[0043] Specifically, the output voltage feedback module is typically connected to the feedback voltage input port of the integrated switching power supply chip to adjust the output voltage of the BOOST power supply module.

[0044] In the overvoltage protection module: the threshold reference voltage V1 generation sub-circuit includes a third resistor R3, a fourth resistor R4, and a third capacitor C3; one end of the third resistor R3 is connected to the logic voltage VCC, and the other end of the third resistor R3 is grounded through the fourth resistor R4, and the other end of the third resistor R3 is also grounded through the third capacitor C3; wherein, the voltage between the third resistor R3 and the fourth resistor R4 is the threshold reference voltage V1; the first low-pass filter sub-circuit includes a fifth resistor R5 and a fourth capacitor C4; one end of the fifth resistor R5 is used to connect to the feedback voltage V2, and the other end of the fifth resistor R5 is grounded through the fourth capacitor C4, and the other end of the fifth resistor R5 is also connected to the inverting input of the first hysteresis comparator; the first hysteresis... The comparator includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a first comparator U1. The inverting input of the first comparator U1 is connected to the other end of the fifth resistor R5. One end of the sixth resistor R6 is used to connect to the threshold reference voltage V1, and the other end of the sixth resistor R6 is connected to the non-inverting input of the first comparator U1. The output of the first comparator U1 is connected to the non-inverting input of the first comparator U1 through the seventh resistor R7. The output of the first comparator U1 is also connected to the logic power supply VCC through the eighth resistor R8. The output of the first comparator U1 is also connected to the digital signal acquisition port of the main control chip, and the output of the first comparator U1 is also connected to the control electrode of the switching transistor Q through the second diode D2.

[0045] Specifically, the logic power supply VCC is divided by the third resistor R3 and the fourth resistor R4, and then filtered by the third capacitor C3. This provides the threshold reference voltage V1 for the first comparator U1, which controls the drive signal of the switching transistor. This voltage is then connected to the non-inverting input of the first comparator U1 via the sixth resistor R6. The output voltage of the BOOST power module is divided by the first resistor R1 and the second resistor R2 to obtain the feedback voltage V2. This feedback voltage V2 is then connected to the inverting input of the first comparator U1 via the first low-pass filter composed of the fifth resistor R5 and the fourth capacitor C4. The first comparator U1 is an open-collector or open-drain output device. The eighth resistor R8 is a pull-up resistor at the output, providing a high level to the output of the first comparator U1. The sixth resistor R6, the seventh resistor R7, and the first comparator U1 form the first hysteresis comparator. Adjusting the values ​​of the sixth resistor R6 and the seventh resistor R7 adjusts the flip-flop threshold voltage of the first hysteresis comparator. The output of the first comparator U1 is connected to the control terminal of the switching transistor Q via the second diode D2; the output of the first comparator U1 is also connected to the digital signal acquisition port O_S_FALT of the main control chip.

[0046] In the overcurrent protection module: the threshold reference voltage V3 generation sub-circuit includes a ninth resistor R9, a tenth resistor R10, and a fifth capacitor C5; one end of the ninth resistor R9 is connected to the logic voltage VCC, and the other end of the ninth resistor R9 is grounded through the tenth resistor R10, and also grounded through the fifth capacitor C5; wherein, the voltage between the ninth resistor R9 and the tenth resistor R10 is the threshold reference voltage V3; the second low-pass filter sub-circuit includes an eleventh resistor R11 and a sixth capacitor C6; one end of the eleventh resistor R11 is used to connect to the sampling voltage V4, and the other end of the eleventh resistor R11 is grounded through the sixth capacitor C6, and also connected to the second hysteresis comparator. The second hysteresis comparator includes a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a second comparator U2. The inverting input of the second comparator U2 is connected to the other end of the eleventh resistor R11. One end of the twelfth resistor R12 is used to connect to the threshold reference voltage V3, and the other end of the twelfth resistor R12 is connected to the non-inverting input of the second comparator U2. The output of the second comparator U2 is connected to the non-inverting input of the second comparator U2 through the thirteenth resistor R13. The output of the second comparator U2 is also connected to the logic power supply VCC through the fourteenth resistor R14. The output of the second comparator U2 is also connected to the control electrode of the switching transistor through the third diode D3.

[0047] Specifically, the logic power supply VCC, after being divided by resistors R9 and R10 and filtered by capacitor C5, provides the threshold reference voltage V3 for the second comparator U2, which controls the drive signal of the switching transistor. This voltage is then connected to the non-inverting input of the second comparator U2 via resistor R12. When the switching transistor Q is turned on, the current flowing through Q is the same as the current flowing through the sampling resistor R, simultaneously generating a sampling voltage V4 across R. This V4 is then connected to the inverting input of the second comparator U2 after passing through a second low-pass filter composed of resistor R11 and capacitor C6. The second comparator U2 uses an open-collector or open-drain output device. Resistor R14 acts as a pull-up resistor at the output, providing a high level to the output of the second comparator U2. Resistors R12 and R13, along with the second comparator U2, form a second hysteresis comparator. Adjusting the values ​​of resistors R12 and R13 adjusts the threshold voltage of the second hysteresis comparator. The output of the second comparator U2 is connected to the control terminal of the switching transistor Q via the third diode D3.

[0048] In the programmable overvoltage protection module: the second-order active filter includes a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, an operational amplifier U3, a seventh capacitor C7, and an eighth capacitor C8; one end of the sixteenth resistor R16 is connected to the second control signal port of the main control chip, and the other end of the sixteenth resistor R16 is connected to the non-inverting input terminal of the operational amplifier U3 through the resistor R17. The other end of the sixteenth resistor R16 is also connected to the output terminal of the operational amplifier U3 through the seventh capacitor C7. The non-inverting input terminal of the operational amplifier U3 is connected to... The eighth capacitor C8 is grounded, and the inverting input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier U3 through the eighteenth resistor R18. The output terminal of the operational amplifier U3 is applied to the threshold reference voltage V1 of the overvoltage protection module through the nineteenth resistor R19. The third low-pass filter sub-circuit includes the twentieth resistor R20 and the ninth capacitor C9. One end of the twentieth resistor R20 is connected to the analog signal acquisition port of the main control chip, and one end of the twentieth resistor R20 is also grounded through the ninth capacitor C9. The other end of the twentieth resistor R20 is connected to the feedback voltage V2.

[0049] Specifically, the feedback voltage V2 is connected to the analog signal acquisition port of the main control chip after passing through the third low-pass filter composed of the twentieth resistor R20 and the ninth capacitor C9. The second control signal port I_P_ADJ of the main control chip is connected to the sixteenth resistor R16. The sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, the operational amplifier U3, the seventh capacitor C7, and the eighth capacitor C8 form a second-order active filter. The output of the second-order active filter is applied to the threshold reference voltage V1 through the nineteenth resistor R19.

[0050] The control method of a conventional BOOST circuit is as follows:

[0051] 1) The first control signal port of the main control chip outputs the first PWM signal I_P_LS, and the switch Q turns on and off alternately. When the switch Q is on, the current flows through the inductor L, the switch Q1 and the sampling resistor R, and the inductor L stores energy. When the switch Q is off, the current flowing through the inductor L charges the second capacitor C2 through the first diode D1, and the inductor L releases energy.

[0052] 2) The analog signal acquisition port of the main control chip acquires the O_A_BAT signal, calculates the output voltage O_V_BAT of the BOOST power module based on the voltage division ratio of the first resistor R1 and the second resistor R2, and adjusts the duty cycle of the first PWM signal I_P_LS output by the first control signal port based on the output voltage O_V_BAT of the BOOST power module.

[0053] 3) In this method, the main control chip needs to continuously collect the feedback voltage V2 and adjust the duty cycle of the first PWM output in real time to ensure the stability of the output voltage. The main control chip has a large amount of computation and occupies a lot of resources.

[0054] 2. The control method of this invention is as follows:

[0055] 1) During initial startup, the main control chip adjusts the duty cycle of the first control signal according to the set voltage value to obtain the first PWM signal, and outputs the first PWM signal I_P_LS through the first control signal port. The switching transistor Q then alternates between turning on and off. When the switching transistor Q is on, current flows through the inductor L, the switching transistor Q, and the sampling resistor R, and the inductor L stores energy. When the switching transistor Q is off, the current flowing through the inductor L charges the second capacitor C2 through the first diode D1, and the inductor L releases energy. This cycle repeats, causing the voltage of the second capacitor C2 to be higher than the input voltage I_V_BAT of the BOOST power module.

[0056] 2) When the feedback voltage V2 is greater than the upper limit of the threshold reference voltage V1, the first comparator U1 outputs a low level, the second diode D2 is turned on, the control electrode of the switch Q becomes low, and the switch Q is turned off. At this time, the main control chip detects that the signal O_S_FALT is low, and the first control signal of the main control chip can be immediately adjusted to a signal with a fixed output duty cycle. That is, the main control chip outputs a second PWM signal I_P_LS with a fixed duty cycle, and then continues to output according to this duty cycle. The turning on and off of the switch Q is jointly controlled by the output terminal of the hardware circuit (overvoltage protection module) and the second PWM signal output by the main control chip.

[0057] 3) When the feedback voltage V2 is less than the lower threshold of the reference voltage V1, the output of the first comparator U1 is high, the switching transistor Q is turned on, and the control electrode of the switching transistor Q is jointly adjusted by the first PWM signal output by the main control chip and the output of the hardware circuit (overvoltage protection module). This process is repeated to ensure the stability of the output voltage.

[0058] 4) When the sampling voltage V4 is greater than the threshold reference voltage V3, the output of the second comparator U2 is low, the third diode D3 is turned on, the control electrode of the switch Q becomes low, the switch Q is turned off, and the overcurrent protection function is activated.

[0059] 5) To change the value of the BOOST power module output voltage O_V_BAT, the main control chip I_P_ADJ port outputs the third PWM signal. This signal is converted into a DC voltage after passing through a second-order low-pass filter and is connected to the nineteenth resistor R19, thereby changing the threshold reference voltage V1.

[0060] 6) The main control chip acquires the voltage value of the O_A_BAT signal, calculates the output voltage O_V_BAT of the BOOST power module, and adjusts the duty cycle of the third PWM signal output from the I_P_ADJ port according to this voltage until the output voltage reaches the set value. Then, the duty cycle of the third PWM signal output from the I_P_ADJ port remains constant.

[0061] In a software-adjustable BOOST circuit of the present invention:

[0062] 1) An overvoltage protection module is provided, and the overvoltage protection module uses a first hysteresis comparator: the threshold reference voltage V1 of the first comparator U1 is set by the sixth resistor R6 and the seventh resistor R7. When the feedback voltage V2 is greater than the larger value of the flip threshold voltage of the first hysteresis comparator (the upper threshold value of the threshold reference voltage V1), the first comparator U1 outputs a low level. When the feedback voltage V2 is less than the smaller value of the flip threshold voltage of the first hysteresis comparator (the lower threshold value of the threshold reference voltage V1), the first comparator U1 outputs a high level.

[0063] 2) Provides a programmable overvoltage protection module: The third PWM signal I_P_ADJ output by the main control chip is converted into a stable DC voltage after passing through a second-order active filter composed of the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, the operational amplifier U3, the seventh capacitor C7, and the eighth capacitor C8. This voltage is then connected to the threshold reference voltage V1 of the first comparator U1 through the nineteenth resistor R19. By changing the duty cycle of the third PWM signal I_P_ADJ, the reference voltage threshold V1 can be changed, thereby changing the output voltage O_V_BAT of the BOOST power module.

[0064] 3) An overcurrent protection module is provided, and the overcurrent protection module uses a second hysteresis comparator: the threshold reference voltage V3 of the second comparator U2 is set by the ninth resistor R9 and the tenth resistor R10 of the voltage divider. When the sampling voltage V4 on the sampling resistor R is greater than the larger value of the flip threshold voltage of the second hysteresis comparator (the upper threshold value of the threshold reference voltage V3), the second comparator U2 outputs a low level. When the sampling voltage V4 on the sampling resistor R is less than the smaller value of the flip threshold voltage of the second hysteresis comparator (the lower threshold value of the threshold reference voltage V3), the second comparator U2 outputs a high level.

[0065] 4) There is a certain difference between the larger and smaller values ​​of the toggle threshold voltage of the hysteresis comparators (first hysteresis comparator and second hysteresis comparator). Therefore, there is a time interval between the high and low level transitions of the hysteresis comparator output, which can greatly reduce the switching frequency of the switching transistor Q and avoid excessive heat generation caused by the switching frequency of the switching transistor Q, which could then damage the switching transistor Q. The larger and smaller values ​​of the toggle threshold voltage can be adjusted by resistors R6, R7, R12, and R13, thereby adjusting the switching frequency of the switching transistor Q (general circuits only use comparators; in actual use, because the toggle threshold of the comparator is a fixed value, when it is greater than or less than this value, the output immediately toggles from low to high or high to low, resulting in a very high frequency at the switching transistor control terminal and a high failure rate of the switching transistor).

[0066] 5) The main control chip only needs to adjust the duty cycle of the first control signal (output the first PWM signal) according to the set voltage value when the power is turned on. After the output voltage reaches the set value, the main control chip has no computational load and only needs to output a PWM signal with a fixed duty cycle (the second PWM signal). All other functions are completed by the hardware circuit, which consumes almost no resources of the main control chip.

[0067] The output voltage value of the BOOST circuit described in this invention can be set by the resistor feedback network or by the main control chip. Furthermore, only during the initial circuit startup phase does the main control chip need to adjust the output duty cycle based on the feedback voltage. Once the output voltage reaches the set value, it only needs to output a PWM signal with a fixed duty cycle; the remaining functions are handled by the hardware circuit. This provides high flexibility and significantly reduces the computational load and resources of the main control chip. This is particularly useful in diesel engine controllers. For diesel engine controllers with the same emission standards, the types and numbers of peripheral sensors do not differ significantly. However, due to inconsistent injector parameters from different manufacturers and varying required drive voltages, the compatibility of diesel engine controllers is poor. Different injectors require different resistance values ​​in the BOOST circuit's resistor feedback network based on the drive voltage. The large variety of diesel engine controllers makes production and management inconvenient. This circuit, after software adaptation, can meet the requirement of using the same diesel engine controller with injectors from different manufacturers.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A BOOST circuit with software-adjustable output voltage, characterized in that: Includes main control chip, BOOST power module, output voltage feedback module and overvoltage protection module; The main control chip is used to adjust the duty cycle of the first control signal according to the set voltage value during initial startup to obtain the first PWM signal, and output it through the first control signal port. It also acts on the control electrode of the switching transistor Q in the BOOST power module to control the switching transistor Q to alternately turn on and off. The BOOST power module is used to repeatedly store and release energy when the switching transistor Q is alternately turned on and off, until the output voltage of the BOOST power module is higher than the input voltage. The output voltage feedback module is used to divide the output voltage of the BOOST power module to obtain the feedback voltage V2; The overvoltage protection module is used to generate a threshold reference voltage V1 and simultaneously acquire the feedback voltage V2. When the feedback voltage V2 is greater than the upper threshold value of the threshold reference voltage V1, it outputs a low level to control the switch Q to turn off, or when the feedback voltage V2 is less than the lower threshold value of the threshold reference voltage V1, it outputs a high level to control the switch Q to turn on, and acts on the control electrode of the switch Q through the second diode D2. The main control chip is also used to adjust the first control signal to a second PWM signal with a fixed duty cycle when the overvoltage protection module outputs a low level, and output it through the first control signal port, and act on the control electrode of the switching transistor Q; The BOOST power module is also used to output a stable voltage under the combined effect of the low level output by the overvoltage protection module and the second PWM signal with a fixed duty cycle output by the main control chip; The BOOST power module is also used to output a stable voltage under the combined effect of the high level output by the overvoltage protection module and the first PWM signal output by the main control chip.

2. The BOOST circuit with software-adjustable output voltage according to claim 1, characterized in that: In the BOOST power module, the switching transistor Q is connected in series with a sampling resistor R, and the current flowing through the switching transistor Q is the same as the current flowing through the sampling resistor R; the BOOST circuit also includes an overcurrent protection module. The overcurrent protection module generates a threshold reference voltage V3 and simultaneously acquires the voltage between the switch Q and the sampling resistor R to obtain a sampling voltage V4. When the sampling voltage V4 is greater than the upper threshold value of the threshold reference voltage V3, it outputs a low level to control the switch Q to turn off, or when the sampling voltage V4 is less than the lower threshold value of the threshold reference voltage V3, it outputs a high level to control the switch Q to turn on. The overcurrent protection is achieved by applying a third diode D3 to the control electrode of the switch Q.

3. The software-adjustable BOOST circuit for output voltage according to claim 1, characterized in that: The main control chip is also used to acquire the feedback voltage V2, calculate the output voltage of the BOOST power module based on the feedback voltage V2, and adjust the duty cycle of the second control signal according to the calculated output voltage of the BOOST power module to obtain a third PWM signal and output it through the second control signal port; the BOOST circuit also includes a programmable overvoltage protection module; The programmable overvoltage protection module is used to convert the third PWM signal output by the main control chip into a stable DC voltage and apply it to the threshold reference voltage V1 of the overvoltage protection module, thereby changing the threshold reference voltage V1 of the overvoltage protection module. The overvoltage protection module is also used to change the output voltage of the BOOST power module when the threshold reference voltage V1 changes.

4. The BOOST circuit with software-adjustable output voltage according to claim 2, characterized in that: The BOOST power module includes an inductor L, a first capacitor C1, a second capacitor C2, a first diode D1, a switching transistor Q, and a sampling resistor R. One end of the inductor L is the input terminal of the BOOST power module and is used to connect to an external power supply. One end of the inductor L is also grounded through the capacitor C1. The other end of the inductor L is connected to the positive terminal of the first diode D1 and the drain of the switching transistor Q. The negative terminal of the first diode D1 is grounded through the second capacitor C2, and the negative terminal of the first diode D1 is the output terminal of the BOOST power module. The source of the switching transistor Q is grounded through the sampling resistor R, and the gate of the switching transistor Q is connected to the first control signal port of the main control chip through the fifteenth resistor R15. The gate of the switching transistor Q is the control terminal of the switching transistor Q, and the voltage between the source of the switching transistor Q and the sampling resistor R is the sampling voltage V4.

5. The software-adjustable BOOST circuit for output voltage according to claim 1, characterized in that: The output voltage feedback module includes a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the output terminal of the BOOST power module, the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded; wherein, the voltage between the first resistor R1 and the second resistor R2 is the feedback voltage V2.

6. The software-adjustable BOOST circuit for output voltage according to claim 1, characterized in that: The overvoltage protection module includes a threshold reference voltage V1 generation sub-circuit, a first hysteresis comparator, and a first low-pass filter sub-circuit. The threshold reference voltage V1 generation sub-circuit is connected to the non-inverting input of the first hysteresis comparator. The inverting input of the first hysteresis comparator is connected to the feedback voltage V2 through the first low-pass filter sub-circuit. The output of the first hysteresis comparator is connected to the digital signal acquisition port of the main control chip. The output of the first hysteresis comparator is also connected to the control electrode of the switching transistor Q through the second diode D2.

7. The software-adjustable BOOST circuit for output voltage according to claim 6, characterized in that: The threshold reference voltage V1 generation sub-circuit includes a third resistor R3, a fourth resistor R4, and a third capacitor C3; one end of the third resistor R3 is connected to the logic voltage VCC, the other end of the third resistor R3 is grounded through the fourth resistor R4, and the other end of the third resistor R3 is also grounded through the third capacitor C3; wherein, the voltage between the third resistor R3 and the fourth resistor R4 is the threshold reference voltage V1; The first low-pass filter sub-circuit includes a fifth resistor R5 and a fourth capacitor C4; one end of the fifth resistor R5 is used to connect to the feedback voltage V2, the other end of the fifth resistor R5 is grounded through the fourth capacitor C4, and the other end of the fifth resistor R5 is also connected to the inverting input of the first hysteresis comparator. The first hysteresis comparator includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a first comparator U1. The inverting input of the first comparator U1 is connected to the other end of the fifth resistor R5. One end of the sixth resistor R6 is used to connect to the threshold reference voltage V1, and the other end of the sixth resistor R6 is connected to the non-inverting input of the first comparator U1. The output of the first comparator U1 is connected to the non-inverting input of the first comparator U1 through the seventh resistor R7. The output of the first comparator U1 is also connected to the logic power supply VCC through the eighth resistor R8. The output of the first comparator U1 is also connected to the digital signal acquisition port of the main control chip, and the output of the first comparator U1 is also connected to the control electrode of the switching transistor Q through the second diode D2.

8. The BOOST circuit with software-adjustable output voltage according to claim 2, characterized in that: The overcurrent protection module includes a threshold reference voltage V3 generation sub-circuit, a second hysteresis comparator, and a second low-pass filter sub-circuit. The threshold reference voltage V3 generation sub-circuit is connected to the non-inverting input terminal of the second hysteresis comparator. The inverting input terminal of the second hysteresis comparator is connected to the sampling voltage V4 through the second low-pass filter sub-circuit. The output terminal of the second hysteresis comparator is connected to the control electrode of the switching transistor through the third diode D3.

9. The software-adjustable BOOST circuit for output voltage according to claim 8, characterized in that: The threshold reference voltage V3 generation sub-circuit includes a ninth resistor R9, a tenth resistor R10, and a fifth capacitor C5; one end of the ninth resistor R9 is connected to the logic voltage VCC, the other end of the ninth resistor R9 is grounded through the tenth resistor R10, and the other end of the ninth resistor R9 is also grounded through the fifth capacitor C5; wherein, the voltage between the ninth resistor R9 and the tenth resistor R10 is the threshold reference voltage V3. The second low-pass filter sub-circuit includes an eleventh resistor R11 and a sixth capacitor C6; one end of the eleventh resistor R11 is used to connect to the sampling voltage V4, the other end of the eleventh resistor R11 is grounded through the sixth capacitor C6, and the other end of the eleventh resistor R11 is also connected to the inverting input of the second hysteresis comparator. The second hysteresis comparator includes a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a second comparator U2. The inverting input of the second comparator U2 is connected to the other end of the eleventh resistor R11. One end of the twelfth resistor R12 is used to connect to the threshold reference voltage V3, and the other end of the twelfth resistor R12 is connected to the non-inverting input of the second comparator U2. The output of the second comparator U2 is connected to the non-inverting input of the second comparator U2 through the thirteenth resistor R13. The output of the second comparator U2 is also connected to the logic power supply VCC through the fourteenth resistor R14. The output of the second comparator U2 is also connected to the control electrode of the switching transistor through the third diode D3.

10. The software-adjustable BOOST circuit for output voltage according to claim 3, characterized in that: The programmable overvoltage protection module includes a second-order active filter and a third low-pass filter sub-circuit. The second-order active filter includes a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, an operational amplifier U3, a seventh capacitor C7, and an eighth capacitor C8. One end of the sixteenth resistor R16 is connected to the second control signal port of the main control chip, and the other end of the sixteenth resistor R16 is connected to the non-inverting input terminal of the operational amplifier U3 through the resistor R17. The other end of the sixteenth resistor R16 is also connected to the output terminal of the operational amplifier U3 through the seventh capacitor C7. The non-inverting input terminal of the operational amplifier U3 is grounded through the eighth capacitor C8, and the inverting input terminal of the operational amplifier U3 is connected to the output terminal of the operational amplifier U3 through the eighteenth resistor R18. The output terminal of the operational amplifier U3 acts on the threshold reference voltage V1 of the overvoltage protection module through the nineteenth resistor R19. The main control chip is connected to the feedback voltage V2 through a third low-pass filter sub-circuit; the third low-pass filter sub-circuit includes a twentieth resistor R20 and a ninth capacitor C9; one end of the twentieth resistor R20 is connected to the analog signal acquisition port of the main control chip, and one end of the twentieth resistor R20 is also grounded through the ninth capacitor C9, and the other end of the twentieth resistor R20 is connected to the feedback voltage V2.

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