Soft start circuit, soft start method, signal generation method and electronic equipment

Abstract

The invention provides a soft start circuit, a soft start method, a signal generation method and electronic equipment. The soft start circuit comprises a biasing circuit, a shunt circuit, a shunt control circuit and an output circuit, the bias circuit is connected with the reference power supply, is connected with the shunt control circuit and the shunt circuit, and is configured to provide bias current and bias voltage based on the reference power supply; the shunt circuit is connected with the output circuit, comprises a plurality of shunt branches arranged in parallel, and is configured to shunt the bias current; the shunt control circuit is connected with the output circuit and comprises a plurality of switch branches, the switch branches are correspondingly connected with the shunt branches, and the shunt control circuit is configured to gate the shunt branches based on the control signal and adjust the bias current; and the output circuit is configured to gradually increase the output voltage based on the current progressive effect of the shunt circuit. The circuit has the technical characteristics of being simple in structure, smooth in starting process, high in output stability and good in zero temperature coefficient characteristic.

Description

Technical Field

[0001] The present application relates to the field of circuit technologies, and particularly to a soft start circuit, a soft start method, a signal generation method, and an electronic device. Background Art

[0002] With the development of integrated circuit technologies, low-voltage and low-power consumption application scenarios are becoming increasingly widespread. As an important power management circuit, a low dropout regulator (LDO) is widely used in systems such as intelligent terminals, wearable devices, and Internet of Things terminals. However, when the low dropout regulator is powered on, there may be an instantaneous impact on the output voltage, resulting in abnormal operation of the subsequent circuit. Therefore, the soft start problem of the low dropout regulator deserves attention. Summary of the Invention

[0003] In view of this, embodiments of the present application provide a soft start circuit, a soft start method, a signal generation method, and an electronic device, aiming to provide a soft start circuit with a simple structure, a smooth start process, high output stability, and excellent zero temperature coefficient characteristics to meet higher-performance power management requirements. In a first aspect, a soft start circuit is provided, including: a bias circuit, a shunt circuit, a shunt control circuit, and an output circuit; the bias circuit is connected to a reference power supply and is also connected to the shunt control circuit and the shunt circuit, and is configured to provide a bias current and a bias voltage based on the reference power supply; the shunt circuit is connected to the output circuit, includes a plurality of shunt branches arranged in parallel, and is configured to shunt the bias current; the shunt control circuit is connected to the output circuit, includes a plurality of switch branches, and the switch branches are correspondingly connected to the shunt branches, and is configured to select and conduct a plurality of shunt branches based on a control signal to adjust the bias current; the output circuit is configured to gradually increase the output voltage based on the current progressive effect of the shunt circuit.

[0004] The above soft start circuit has the performance characteristics of a smooth soft start process and no voltage jump, the output voltage is less affected by temperature changes, has excellent zero temperature coefficient characteristics, and the circuit structure is simple and easy to integrate. The start control does not require an external large-capacity capacitor, saving chip area. The present application can significantly improve the stability and overall performance of the power supply system, and is particularly suitable for application scenarios that are sensitive to startup voltage changes or have high requirements for system reliability.

[0005] Optionally, the bias circuit includes: a first current source, a first bias switching transistor, a second bias switching transistor, a third bias switching transistor, and a fourth bias switching transistor; the first bias switching transistor is configured to generate a first bias voltage based on the bias current of the first current source, wherein the drain of the first bias switching transistor is connected to the first current source and the gate of the first bias switching transistor, and the gate of the first bias switching transistor is connected to the gate of the second switching transistor; the drain of the second bias switching transistor is coupled to the drain of the third bias switching transistor, the gate of the second bias switching transistor is coupled to the shunt circuit, and the source of the first bias switching transistor and the source of the second bias switching transistor are grounded; the third bias switching transistor is configured to generate a second bias voltage based on the bias current, wherein the drain of the third bias switching transistor is coupled to the gate of the third bias switching transistor, the source of the third bias switching transistor and the source of the fourth bias switching transistor are coupled to a reference power supply, and the gate of the third bias switching transistor is coupled to the gate of the fourth bias switching transistor; the drain of the fourth bias switching transistor is coupled to the shunt control circuit.

[0006] Optionally, the switching branch includes: a first switching transistor; the shunt branch includes: a first transistor; the drain of the first switching transistor is coupled to the drain of the fourth bias switching transistor, the source of the first switching transistor is coupled to the drain of the first transistor, and the gate of the first switching transistor is coupled to a control signal; the source of the first transistor is grounded, the gate of the first transistor is coupled to the gate of the second bias switching transistor, and among multiple shunt branches, the gates of multiple first transistors are connected to each other.

[0007] Optionally, the output circuit includes: a first resistor and a first capacitor; the first end of the first resistor is coupled to the drain of the first switching transistor, and the second end is coupled to the source of the first transistor; the first capacitor is in parallel with the first resistor, and the first end of the first capacitor serves as the output terminal of the soft start circuit.

[0008] Optionally, it further includes: a control circuit configured to provide a control signal to the shunt control circuit. The control circuit includes: a NOT logic gate, an OR logic gate, a second capacitor, a first flip-flop switch, a second flip-flop switch, and a Schmitt trigger; the input terminal of the NOT logic gate is coupled to the enable signal of the soft start circuit, and the output terminal is coupled to the first input terminal of the OR logic gate; the second input terminal of the OR logic gate is coupled to a first signal, and the output terminal of the OR logic gate is coupled to the gate of the first flip-flop switch; a second capacitor is coupled between the source and the drain of the first flip-flop switch, and the source is grounded; the gate of the second flip-flop switch is coupled to the gate of the first flip-flop switch, the source of the second flip-flop switch is coupled to a second current source, and the drain of the second flip-flop switch is coupled to the drain of the first flip-flop switch; the input terminal of the Schmitt trigger is coupled to the drain of the first flip-flop switch, and the output terminal outputs the first signal.

[0009] Optionally, the shunt control circuit further includes: a plurality of D flip-flops configured to combinatorially determine the control signal according to a preset switching logic.

[0010] In a second aspect, a soft start method is provided for the soft start circuit in the first aspect, including: generating a bias current and a bias voltage based on a bias circuit; shunting the bias current through a shunt circuit to reduce the initial output voltage; controlling the shunt control circuit to turn off multiple shunt branches of the shunt circuit, reducing the shunt current, and increasing the output voltage until a predetermined output voltage value is reached.

[0011] In a third aspect, a method for generating a control signal of a soft start circuit is provided for the control circuit of the soft start circuit in the first aspect, including: when the enable signal is configured to be at a low level, the gate voltage of the first flip-flop switch is at a high level, the first flip-flop switch is in a conducting state, and the second flip-flop switch is in a non-conducting state; controlling the enable signal to be at a high level, adjusting the first flip-flop switch to be in a non-conducting state, the second flip-flop switch to be in a conducting state, and charging the second capacitor through the second flip-flop switch. When the voltage of the second capacitor reaches a first threshold voltage, controlling the output of a first signal; using the first signal to drive the first flip-flop switch to be in a conducting state and the second flip-flop switch to be in a non-conducting state, so that the second capacitor discharges through the first flip-flop switch. When the voltage of the second capacitor reaches a second threshold voltage, controlling the stop of the output of the first signal, thereby generating a periodic control signal.

[0012] In a fourth aspect, a soft start device is provided, including: a bias unit for generating a bias current and a bias voltage based on a bias circuit; a shunt unit for shunting the bias current through a shunt circuit to reduce the initial output voltage; a control unit for controlling the shunt control circuit to turn off multiple shunt branches of the shunt circuit, reducing the shunt current, and increasing the output voltage until a predetermined output voltage value is reached.

[0013] In a fifth aspect, an electronic device is provided, including the soft start circuit in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The following briefly introduces the drawings used in the description of the embodiments of the present application: Figure 1 Shows a schematic circuit diagram of a soft start circuit provided in some embodiments of the present application; Figure 2 Shows a schematic circuit diagram of another soft start circuit provided in some embodiments of the present application; Figure 3 Shows a waveform schematic diagram of the start-up process of a soft start circuit provided in some embodiments of the present application; Figure 4 Shows a schematic diagram of the structure of a control circuit provided in some embodiments of the present application; Figure 5 Shows a timing waveform schematic diagram of a control circuit provided in some embodiments of the present application; Figure 6 The flowchart of a soft start method provided in some embodiments of the present application is shown; Figure 7 The flowchart of a method for generating a control signal of a soft start circuit provided in some embodiments of the present application is shown; Figure 8 The structural schematic diagram of a soft start device provided in some embodiments of the present application is shown. Detailed implementation manners

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the specific implementation manners of the present application will be described below with reference to the accompanying drawings. The accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings or embodiments can be obtained based on these drawings or embodiments. Adjustments and improvements made without departing from the concept of the present application all fall within the protection scope of the present application.

[0016] To make the drawings concise, each drawing only schematically shows the parts related to the embodiments, and they do not represent the actual structure of the product. Additionally, to make the drawings concise and easy to understand, in some drawings, parts with the same structure or function are only schematically shown partially, and there may actually be more or fewer parts with the same structure or function.

[0017] With the development of integrated circuit technology, low-voltage and low-power consumption application scenarios are becoming increasingly widespread. As an important power management circuit, the low-dropout linear regulator (LDO) is widely used in systems such as smart terminals, wearable devices, and Internet of Things terminals. The LDO can adjust the input voltage to an accurate output voltage. Its working principle is based on the feedback principle. Through internal components such as an adjustment transistor, an amplifier, and a feedback resistor, it can stably maintain the output voltage at the set value. It usually has extremely low self-noise and a high power supply rejection ratio (PSRR), which makes it very useful in applications that require a low-noise power supply. In traditional designs, it is required to have a low dropout voltage, a high-precision output voltage, and good load transient response capabilities. In practical applications, to avoid abnormal operation of the subsequent circuit caused by the instantaneous impact of the output voltage during power-on, or power supply noise problems caused by sudden changes in the load current, the LDO usually needs to have a soft-start function. Through soft start, the output voltage can rise gradually at a set rate, reducing the current impact during the start-up phase of the system, protecting the load circuit, and improving the stability and reliability of the overall system. The existing implementation schemes of LDOs generally have the following problems: First, the soft-start process depends on external capacitors or complex control logic, increasing the system volume or design complexity; second, the linearity and controllability of soft start are insufficient, easily leading to uneven rise or even oscillation of the output voltage; third, under temperature change conditions, the output voltage stability of the circuit is poor, and the temperature drift has a greater impact. Therefore, there is an urgent need for an LDO design with a simple structure, a smooth start-up process, high output stability, and good zero-temperature coefficient characteristics to meet the higher-performance power management requirements.

[0018] This application aims to provide a soft-start circuit to overcome the problems of uneven soft start, large temperature drift, and complex structure in the prior art.

[0019] The following is a description with reference to the accompanying drawings: Figure 1The schematic circuit diagram of a soft-start circuit provided in some embodiments of the present application is shown. In a first aspect, a soft-start circuit is provided, including: a bias circuit 110, a shunt circuit 120, a shunt circuit 130, and an output circuit 140; the bias circuit 110 is connected to a reference power supply and is also connected to the shunt circuit 130 and the shunt circuit 120, and is configured to provide a bias current and a bias voltage based on the reference power supply; the shunt circuit 120 is connected to the output circuit 140, includes a plurality of shunt branches arranged in parallel, and is configured to shunt the bias current; the shunt circuit 130 is connected to the output circuit 140, includes a plurality of switch branches, and the switch branches are correspondingly connected to the shunt branches, and is configured to selectively connect a plurality of shunt branches based on a control signal to adjust the bias current; the output circuit 140 is configured to gradually increase the output voltage based on the current progression effect of the shunt circuit 120.

[0020] The above soft-start circuit generates a bias current and a bias voltage through a reference power supply. The plurality of switch branches in the shunt circuit 130 are correspondingly connected to the plurality of shunt branches in the shunt circuit 120, so that under the action of at least one control signal, the plurality of switch branches turn on or off each shunt branch, and control the output voltage to gradually rise in a stepped manner, realizing a gradual increase in voltage during the start-up process of the soft-start circuit, so that the output voltage has a certain proportional relationship with the input voltage. The soft-start circuit provided in the present application has the performance characteristics of a smooth soft-start process and no voltage jump, the output voltage is less affected by temperature changes, has an excellent zero temperature coefficient characteristic, and has a simple circuit structure, is easy to integrate, and does not require an external large-capacity capacitor for start-up control, saving chip area. Through the above improvements, the present application can significantly improve the stability and overall performance of the power supply system, and is particularly suitable for application scenarios that are sensitive to start-up voltage changes or have high requirements for system reliability.

[0021] Figure 2The figure shows a schematic circuit diagram of another soft start circuit provided in some embodiments of the present application. The bias circuit 110 includes: a first current source Is1, a first bias switching transistor B1, a second bias switching transistor B2, a third bias switching transistor B3, and a fourth bias switching transistor B4; the first bias switching transistor B1 is configured to generate a first bias voltage based on the bias current of the first current source Is1, wherein the drain of the first bias switching transistor B1 is connected to the first current source Is1 and the gate of the first bias switching transistor B1, and the gate of the first bias switching transistor B1 is connected to the gate of the second switching transistor; the drain of the second bias switching transistor B2 is coupled to the drain of the third bias switching transistor B3, the gate of the second bias switching transistor B2 is coupled to the shunt circuit 120, and the source of the first bias switching transistor B1 and the source of the second bias switching transistor B2 are grounded; the third bias switching transistor B3 is configured to generate a second bias voltage based on the bias current, wherein the drain of the third bias switching transistor B3 is coupled to the gate of the third bias switching transistor B3, the source of the third bias switching transistor B3 and the source of the fourth bias switching transistor B4 are coupled to the reference power supply, and the gate of the third bias switching transistor B3 is coupled to the gate of the fourth bias switching transistor B4; the drain of the fourth bias switching transistor B4 is coupled to the shunt circuit 130.

[0022] In the above embodiments, the first current source Is1 generates a bias current, and then the first bias switching transistor B1 generates a first bias voltage and supplies it to the second bias switching transistor B2. The second bias switching transistor B2 is used as an auxiliary bias to stabilize the reference of the branch current and ensure that the shunt branch operates in a suitable operating range. The third bias switching transistor B3 generates a second bias voltage and supplies it to the fourth bias switching transistor B4, and the fourth bias switching transistor B4 generates a stable bias current for the current distribution of the subsequent shunt branch. At the same time, the second bias switching transistor B2 provides a stable gate voltage reference for the transistors in multiple shunt branches, ensuring that in the soft start process of multiple shunt branches, even with the operation of the switching branch, the transistors in the shunt branch can still maintain the correct bias and the shunt current will not be inaccurate or drift due to unstable gate-source voltage.

[0023] Continue to refer to Figure 2 , the switching branch includes: a first switching transistor S1; the shunt branch includes: a first transistor M1; the drain of the first switching transistor S1 is coupled to the drain of the fourth bias switching transistor B4, the source of the first switching transistor S1 is coupled to the drain of the first transistor M1, and the gate of the first switching transistor S1 is coupled to the control signal; the source of the first transistor M1 is grounded, the gate of the first transistor M1 is coupled to the gate of the second bias switching transistor B2, and among multiple shunt branches, the gates of multiple first transistors M1 are connected to each other.

[0024] The output circuit 140 includes: a first resistor R1 and a first capacitor C1; a first end of the first resistor R1 is coupled to a drain of a first switching transistor S1, and a second end is coupled to a source of a first transistor M1; the first capacitor C1 is connected in parallel with the first resistor R1, and a first end of the first capacitor C1 serves as an output end of the soft-start circuit.

[0025] The above-mentioned shunt circuit 130 may include multiple first switching transistors S1, and the shunt circuit 120 may include multiple first transistors M1. The first switching transistor S1 and the first transistor M1 on the same branch are correspondingly connected. For example, a source of the first switching transistor S1 is connected to a drain of the first transistor M1. Exemplarily, in n shunt branches composed of the first switching transistor S1 and the first transistor M1, shunt branches with currents I1, I2, ……, In are formed. By setting the sizes of multiple first transistors M1 to Mn, the sum of currents I1 to In is made less than a bias current ITOL provided by a fourth bias switching transistor B4. Before the soft-start circuit is enabled, the initial voltage of the output voltage Vout1 can be represented by Equation 1:

[0026] Wherein, the current ITOL is the current flowing into the shunt circuit 130 through the fourth bias switching transistor B4.

[0027] After the soft-start circuit is enabled, the shunt circuit 130 turns off the first switching transistors S1 to Sn step by step, so that the voltage rises step by step. When the kth switch is turned off, the output voltage Vout can be represented by Equation 2:

[0028] After all the first switching transistors S1 to Sn are turned off, the output voltage Vout1 can be represented by Equation 3:

[0029] It can be known from the above formula that the final output voltage Vout1 is in a proportional relationship with the voltage VBG of the current Is1 forming the current source. The shunted and converged current forms the output voltage Vout1 on the first resistor R1, and the final output voltage Vout is generated under the stabilizing effect of the first capacitor C1. Therefore, through the loop feedback characteristic of the soft-start circuit, it can be determined that the final output voltage Vout is also in a proportional relationship with VBG, so as to achieve a stable supply voltage with zero temperature coefficient. It should be noted that the final output voltage Vout can be used as a reference voltage Vref of a low-dropout linear regulator.

[0030] Figure 3The waveform diagram of the startup process of a soft startup circuit provided in some embodiments of the present application is shown. In the figure, EN is the enable signal, CTR1 represents the trigger signal of the first switch tube S1, CTR2 represents the trigger signal of the first switch tube S2, and CTRn represents the trigger signal of the first switch tube Sn. It can be known that the output voltage Vout1 shows a stepwise rising trend during the process of the first switch tube being gradually turned off. Under the action of the first capacitor C1, the waveform of the output voltage is further smoothed to form the output voltage Vout2.

[0031] Figure 4 The structural diagram of a control circuit provided in some embodiments of the present application is shown. The control circuit is configured to provide a control signal to the shunt circuit 130. The control circuit includes: a NOT logic gate, an OR logic gate, a second capacitor, a first flip-flop switch, a second flip-flop switch, and a Schmitt trigger; the input end of the NOT logic gate is coupled to the enable signal of the soft startup circuit, and the output end is coupled to the first input end of the OR logic gate; the second input end of the OR logic gate is coupled to a first signal, and the output end of the OR logic gate is coupled to the gate of the first flip-flop switch; a second capacitor is coupled between the source and the drain of the first flip-flop switch, and the source is grounded; the gate of the second flip-flop switch is coupled to the gate of the first flip-flop switch, the source of the second flip-flop switch is coupled to a second current source, and the drain of the second flip-flop switch is coupled to the drain of the first flip-flop switch; the input end of the Schmitt trigger is coupled to the drain of the first flip-flop switch, and the output end outputs the first signal.

[0032] In the above control circuit, EN is the enable signal of the low dropout linear regulator. Before the low dropout linear regulator is enabled, the enable signal EN is at a low level. At this time, the first signal CT1 is at a high level, controlling the first flip-flop switch SWN1 to turn on and the second flip-flop switch SWP1 to turn off. The voltage Vc on the second capacitor Cc is 0V. When the enable signal EN of the low dropout linear regulator is at a high level, the second flip-flop switch SWP1 conducts, the first flip-flop switch SWN1 turns off, and the bias current Ib charges the second capacitor Cc, causing the voltage Vc on the second capacitor Cc to rise linearly. When the voltage Vc rises to the rising flip voltage VH of the Schmitt trigger, the output level SM_O of the Schmitt trigger is set to 1, controlling the first flip-flop switch SWN1 to turn on and the second flip-flop switch SWP1 to turn off. The capacitor CC discharges through SWN1. When the VC voltage drops to the falling flip voltage VL of the Schmitt trigger, the output level SM_O of the Schmitt trigger is set to 0, controlling the first flip-flop switch SWN1 to turn off and the second flip-flop switch SWP1 to turn on. Figure 5The figure shows a schematic diagram of the timing waveform of a control circuit provided in some embodiments of the present application. According to the above control process cycle, the output level SM_O of the final Schmitt trigger outputs a periodic square wave signal. In the subsequent circuit, a combinational logic can be formed through a flip-flop or other signal control devices to control the conduction or cutoff of multiple switching devices in the shunt circuit 130.

[0033] In some embodiments, with continued reference to Figure 4 , the control circuit further includes: a plurality of D flip-flops configured to combinatorially determine a control signal according to a preset switching logic.

[0034] Figure 6 The figure shows a schematic flowchart of a soft start method provided in some embodiments of the present application. This soft start method is used for the soft start circuit provided in the above embodiments and includes: S610: Generate a bias current and a bias voltage based on a bias circuit; S620: Shunt the bias current through a shunt circuit to reduce the initial output voltage; S630: Control the shunt control circuit to turn off multiple shunt branches of the shunt circuit, reduce the shunt current, and increase the output voltage until a predetermined output voltage value is reached.

[0035] The specific principle and effect of the above soft start method have been explained in the above embodiments and will not be elaborated here.

[0036] Figure 7 The figure shows a schematic flowchart of a method for generating a control signal of a soft start circuit provided in some embodiments of the present application. This control signal generation method is used for the control circuit of the soft start circuit in the first aspect and includes: S710: When the enable signal is configured to be at a low level, the gate voltage of the first flip-flop switch is at a high level, the first flip-flop switch is in a conducting state, and the second flip-flop switch is in a cutoff state; S720: Control the enable signal to be at a high level, adjust the first flip-flop switch to be in a cutoff state, the second flip-flop switch to be in a conducting state, and charge the second capacitor through the second flip-flop switch. When the voltage of the second capacitor reaches the first threshold voltage, control the output of the first signal; S730: Use the first signal to drive the first flip-flop switch to be in a conducting state and the second flip-flop switch to be in a cutoff state, so that the second capacitor discharges through the first flip-flop switch. When the voltage of the second capacitor reaches the second threshold voltage, control the stop of the output of the first signal, thereby generating a periodic control signal.

[0037] The specific principle and effect of the above control signal generation method have been explained in the above embodiments and will not be elaborated here.

[0038] Based on the same inventive concept, Figure 8 FIG. Figure 8 shows a schematic structural diagram of a soft start device provided in some embodiments of the present application, including: a bias unit 810 for generating a bias current and a bias voltage based on a bias circuit; a shunt unit 820 for shunting the bias current through a shunt circuit to reduce the initial output voltage; and a control unit 830 for controlling the shunt control circuit to turn off multiple shunt branches of the shunt circuit, reduce the shunt current, and increase the output voltage until a predetermined output voltage value is reached.

[0039] For the specific implementation manners and beneficial effects of the above soft start device, reference can be made to the specific descriptions of the embodiments of the above soft start circuit and soft start method, which will not be elaborated here. The above division of each unit is only a division of logical functions. In actual implementation, all or part of them can be integrated into one physical entity, or physically separated. In addition, the above units can be implemented in the form of a processor calling software. Alternatively, the above units can be implemented in the form of a hardware circuit, and the functions of some or all of the units can be realized by designing the hardware circuit, which can be understood as one or more processors; for example, in some embodiments, the hardware circuit is an application specific integrated circuit (ASIC), and the functions of some or all of the above units are realized by designing the logical relationship between the components in the circuit; again, in another implementation, the hardware circuit can be implemented by a programmable logic device (PLD), which can include a large number of logic gate circuits, and the logical relationship between the logic gate circuits is configured through a configuration file to realize the functions of some or all of the above units. The units of the above device can all be implemented in the form of a processor calling a program, or all be implemented in the form of a hardware circuit, or part be implemented in the form of a processor calling a program, and the remaining part be implemented in the form of a hardware circuit.

[0040] Based on the same inventive concept, the present application further provides an electronic device including the soft start circuit provided in the above embodiments.

[0041] In the present application, unless otherwise clearly specified and limited, ordinal numbers such as "first", "second", etc. are only used to distinguish and describe related objects, and cannot be understood as indicating or implying the relative importance or order between related objects. In addition, ordinal numbers do not represent the number of related objects. For example, "the first capacitor" may include one capacitor or multiple capacitors.

[0042] "Multiple" includes two or more, and other quantifiers are similar.

[0043] The terms "or" and "and / or" in this application are used to describe the relationship between related objects, indicating non-exclusive inclusion. For example, both "A and / or B" and "A or B" can include: "A alone", "B alone", or "A and B", where "A" and "B" can include single objects or multiple objects. Another example, "A, B, and / or C", "A, B, or C", and "A, B, and C" can all include: "A alone", "B alone", "C alone", "A and B", "A and C", "B and C", or "A, B, and C", where "A", "B", and "C" can include single objects or multiple objects. Additionally, " / " in this application is used to indicate the "or" relationship between the related objects before and after. The meanings of "at least one of A or B" and "one or more of A and B" in this application are the same as the meaning of "A or B" above, and the meanings of "one or more of A, B, and C" and "at least one of A, B, or C" are the same as the meaning of "A, B, or C" above. The meaning of "one or more of A, B, and C" is the same as the meaning of "A, B, or C" above.

[0044] In the above embodiments, the descriptions of each embodiment have their own emphases. For parts not detailedly described or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. In addition, the above embodiments can be freely combined as needed.

Claims

1. A soft start circuit, characterized in that, Comprising: A bias circuit, a shunt circuit, a shunt control circuit, and an output circuit; The bias circuit, connected to a reference power supply, and connected to the shunt control circuit and the shunt circuit, is configured to provide a bias current and a bias voltage based on the reference power supply; The shunt circuit, connected to the output circuit, includes a plurality of shunt branches arranged in parallel, and is configured to shunt the bias current; The shunt control circuit, connected to the output circuit, includes a plurality of switch branches, the switch branches are correspondingly connected to the shunt branches, and are configured to select a plurality of the shunt branches based on a control signal to adjust the bias current; The output circuit is configured to gradually increase the output voltage based on the current progressive effect of the shunt circuit.

2. The soft start circuit according to claim 1, characterized in that, The bias circuit includes: a first current source, a first bias switching transistor, a second bias switching transistor, a third bias switching transistor, and a fourth bias switching transistor; The first bias switching transistor is configured to generate a first bias voltage based on the bias current of the first current source, wherein the drain of the first bias switching transistor is connected to the first current source and the gate of the first bias switching transistor, and the gate of the first bias switching transistor is connected to the gate of the second bias switching transistor; The drain of the second bias switching transistor is coupled to the drain of the third bias switching transistor, the gate of the second bias switching transistor is coupled to the shunt circuit, and the source of the first bias switching transistor and the source of the second bias switching transistor are grounded; The third bias switching transistor is configured to generate a second bias voltage based on the bias current, wherein the drain of the third bias switching transistor is coupled to the gate of the third bias switching transistor, the source of the third bias switching transistor and the source of the fourth bias switching transistor are coupled to the reference power supply, and the gate of the third bias switching transistor is coupled to the gate of the fourth bias switching transistor; The drain of the fourth bias switching transistor is coupled to the shunt control circuit.

3. The soft start circuit according to claim 2, wherein The switch branch includes: a first switching transistor; the shunt branch includes: a first transistor; The drain of the first switching transistor is coupled to the drain of the fourth bias switching transistor, the source of the first switching transistor is coupled to the drain of the first transistor, and the gate of the first switching transistor is coupled to the control signal; The source of the first transistor is grounded, the gate of the first transistor is coupled to the gate of the second bias switching transistor, and between a plurality of the shunt branches, the gates of a plurality of the first transistors are connected to each other.

4. The soft start circuit according to claim 3, wherein, The output circuit includes: a first resistor and a first capacitor; The first end of the first resistor is coupled to the drain of the first switching transistor, and the second end is coupled to the source of the first transistor; The first capacitor is in parallel with the first resistor, and the first end of the first capacitor serves as the output end of the soft start circuit.

5. The soft start circuit according to any one of claims 1-4, characterized in that, Further comprising: A control circuit, configured to provide a control signal to the shunt control circuit, the control circuit includes: a NOT logic gate, an OR logic gate, a second capacitor, a first flip-flop switch, a second flip-flop switch, and a Schmitt trigger; The input end of the NOT logic gate is coupled to the enable signal of the soft start circuit, and the output end is coupled to the first input end of the OR logic gate; The second input terminal of the OR logic gate is coupled to a first signal, and the output terminal of the OR logic gate is coupled to the gate of the first flip-flop switch; A second capacitor is coupled between the source and the drain of the first flip-flop switch, and the source is grounded; The gate of the second flip-flop switch is coupled to the gate of the first flip-flop switch, the source of the second flip-flop switch is coupled to a second current source, and the drain of the second flip-flop switch is coupled to the drain of the first flip-flop switch; The input terminal of the Schmitt trigger is coupled to the drain of the first flip-flop switch, and the output terminal outputs the first signal.

6. The soft start circuit according to claim 5, characterized in that, The shunt control circuit further includes: a plurality of D flip-flops configured to combinatorially determine the control signal according to a preset switching logic.

7. A soft start method, characterized in that, A soft start circuit for any one of claims 1-6, comprising: Generating the bias current and the bias voltage based on the bias circuit; Shunting the bias current through the shunt circuit to reduce the initial output voltage; Controlling the shunt control circuit to turn off the plurality of shunt branches of the shunt circuit, reducing the shunt current, and increasing the output voltage until a predetermined output voltage value is reached.

8. A method for generating a control signal of a soft start circuit, characterized in that The control circuit for the soft start circuit of claim 5, comprising: When the enable signal is configured to be at a low level, the gate voltage of the first flip-flop switch is at a high level, the first flip-flop switch is in an on state, and the second flip-flop switch is in an off state; Controlling the enable signal to be at a high level, adjusting the first flip-flop switch to an off state and the second flip-flop switch to an on state, and charging the second capacitor through the second flip-flop switch. When the voltage of the second capacitor reaches a first threshold voltage, controlling the output of the first signal; Utilizing the first signal to drive the first flip-flop switch to be in an on state and the second flip-flop switch to be in an off state, so that the second capacitor discharges through the first flip-flop switch. When the voltage of the second capacitor reaches a second threshold voltage, controlling the stop of the output of the first signal, thereby generating a periodic control signal.

9. A soft start device, characterized in that, The control circuit for the soft start circuit of claim 5, comprising: A bias unit for generating the bias current and the bias voltage based on the bias circuit; A shunt unit for shunting the bias current through the shunt circuit to reduce the initial output voltage; A control unit for controlling the shunt control circuit to turn off the plurality of shunt branches of the shunt circuit, reducing the shunt current, and increasing the output voltage until a predetermined output voltage value is reached.

10. An electronic device, characterized in that, Comprising the soft start circuit of any one of claims 1-6.

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