Slow start circuit and electronic equipment

Abstract

The utility model relates to the field of electronic circuits, and provides a slow start circuit and electronic equipment, and the slow start circuit is connected with a slow start module at a controlled end of a switch module, and can carry out the shunting of a conduction signal used for driving the conduction of the switch module, thereby reducing the voltage climbing speed of the controlled end of the switch module, reducing the switching-on speed of the switch module, and improving the switching efficiency of the switch module. And the surge current is further reduced. Therefore, on the premise that the cost of the switch module is not increased, the surge current is reduced, and the safety of the load is protected.

Description

Technical Field

[0001] This application belongs to the field of electronic circuits, and particularly relates to a soft-start circuit and an electronic device. Background Art

[0002] In some application scenarios where the rated operating current is large and the load capacitance is also large, a normal hot-swap protection circuit may not meet the design requirements. For example, if the rated operating current is large, the current limiting value will be set very large, so the inrush current during the inrush stage will be very large, which may affect the stable power supply of the normally operating load and there is a risk of damage. In addition, the requirements for the safety operation area (SOA) of the metal-oxide-semiconductor field-effect transistor (MOSFET) on the power supply transmission line are more stringent, the selection of MOSFET will be very difficult, and the price will be more expensive, increasing the cost. Summary of the Utility Model

[0003] The purpose of this application is to provide a soft-start circuit and an electronic device, aiming to solve the problem that in application scenarios with a large rated operating current, the inrush current may damage the load and increase the cost of MOSFET.

[0004] In a first aspect, an embodiment of this application provides a soft-start circuit, including:

[0005] A switch module for being connected in series on the power supply transmission line;

[0006] A driving module connected to the controlled end of the switch module, for outputting a conduction signal or a cut-off signal to the controlled end of the switch module to drive the switch module to conduct or cut off;

[0007] A soft-start module connected to the controlled end of the switch module, for shunting the conduction signal to reduce the voltage rising speed of the controlled end of the switch module, so as to slow down the turn-on speed of the switch module.

[0008] In some embodiments, the soft-start module includes an energy storage element, and the energy storage element is used for charging to shunt the conduction signal.

[0009] In some embodiments, the soft-start module further includes a release element connected to the energy storage element, and the release element is used to release the energy stored in the energy storage element in response to the cut-off signal.

[0010] In some embodiments, the soft-start module further includes a unidirectional conduction element, and the unidirectional conduction element is connected in series in the forward direction between the controlled end of the switch module and the energy storage element.

[0011] In some embodiments, the release element includes a first switching transistor, the first switching transistor is connected in parallel with the energy storage element, and a controlled terminal of the first switching transistor is connected to a controlled terminal of the switching module, and the first switching transistor is turned on in response to the turn-off signal.

[0012] In some embodiments, the driving module includes:

[0013] A driving unit, an input terminal of which is connected to a power input terminal of the power supply transmission line, and an output terminal of which is connected to a controlled terminal of the switching module, and the driving unit is configured to output the turn-on signal based on a voltage of the power input terminal;

[0014] A turn-off unit, configured to receive a detection signal and output the turn-off control signal in response to a detection signal greater than a threshold;

[0015] A switching unit, a control terminal of which is connected to the turn-off circuit, a first conducting terminal of which is connected to the controlled terminal of the switching module, and a second conducting terminal of which is grounded, and the switching unit is turned on in response to the turn-off control signal.

[0016] In some embodiments, a first detection module is further included, the first detection module is connected to the power supply transmission line and the turn-off unit, the first detection module is configured to detect a power parameter transmitted by the power supply transmission line and output a first detection signal corresponding to the power parameter, and the turn-off unit is further configured to output the turn-off control signal in response to the first detection signal exceeding a power parameter threshold.

[0017] In some embodiments, a second detection module is further included, the second detection module is connected to the switching module and the turn-off unit, the second detection module is configured to detect a voltage drop across the switching module and output a second detection signal corresponding to the voltage drop, and the turn-off unit is further configured to output the turn-off control signal in response to the second detection signal exceeding a voltage threshold.

[0018] In some embodiments, the switching unit includes a first resistor, a second resistor, a first capacitor, and a second switching transistor;

[0019] The first resistor is connected between the turn-off unit and the controlled terminal of the second switching transistor; a first end of the first capacitor is connected to the controlled terminal of the second switching transistor, and a second end of the first capacitor is grounded; a first conducting end of the second switching transistor is connected to the controlled terminal of the switching module, and a second conducting end of the second switching transistor is grounded through the second resistor.

[0020] In a second aspect, an embodiment of the present application further provides an electronic device, including the soft start circuit as described above.

[0021] The above-mentioned soft-start circuit can shunt the conduction signal for driving the switch module to conduct by connecting a soft-start module to the controlled end of the switch module, thereby reducing the voltage rise speed at the controlled end of the switch module, slowing down the turn-on speed of the switch module, and further reducing the inrush current. In this way, the inrush current can be reduced and the safety of the load can be protected without increasing the cost of the switch module. Description of the Drawings

[0022] Figure 1 FIG. is a schematic structural diagram of the soft-start circuit provided by an embodiment of the present application;

[0023] Figure 2 FIG. is a circuit diagram of the soft-start circuit provided by an embodiment of the present application. Detailed Embodiments

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0028] Please refer to Figure 1 , a soft-start circuit provided by an embodiment of the present application includes a switch module Q1, a driving module 110, and a soft-start module 120.

[0029] The switch module Q1 is used to be connected in series on the power supply transmission line to control the conduction and cutoff of the power supply transmission line; the driving module 110 is connected to the controlled end of the switch module Q1 and is used to output a conduction signal or a cutoff signal to the controlled end of the switch module Q1 to drive the switch module Q1 to conduct or cutoff; the soft start module 120 is connected to the controlled end of the switch module Q1, and the soft start module 120 is used to shunt the conduction signal to reduce the voltage rising speed of the controlled end of the switch module Q1 so as to slow down the turn-on speed of the switch module Q1.

[0030] The switch module Q1 is, for example, an N-channel MOS transistor, and the conduction signal and the cutoff signal are a high-level signal and a low-level signal respectively. It can be understood that the soft start module 120 responds to the conduction signal and shunts it, that is, it is used to shunt the conduction signal initially output by the driving module 110 for a period of time to reduce the voltage rising speed of the controlled end of the switch module Q1 so as to slow down the turn-on speed of the switch module Q1, thereby reducing the inrush current. After the switch module Q1 is fully conducted, the shunting of the conduction signal can be stopped.

[0031] Please refer to Figure 2 , in some embodiments, the soft start module 120 includes an energy storage element C1, and the energy storage element C1 is used to charge to shunt the conduction signal.

[0032] Among them, the energy storage element C1 is, for example, a capacitor. When the driving module 110 outputs a conduction signal, the conduction signal charges the energy storage element C1, and when the VGS of the switch module Q1, such as a MOS transistor, reaches the turn-on threshold, it conducts. Among them, when the MOS transistor is semi-conducted, due to the Miller plateau effect of the MOS transistor, the potential difference between the gate and the source remains unchanged. At this time, the voltage of the gate and the dV / dt of the output voltage (source) (that is, the change rate of the voltage with time (rising or falling)) are exactly the same. Therefore, the voltage rising speed of the controlled end can be reduced to reduce the voltage rising speed of the output voltage, thereby effectively slowing down the turn-on speed of the switch module Q1 and reducing the inrush current. Optionally, the switch module Q1 can also be other types of transistors, such as an Insulate-Gate Bipolar Transistor (IGBT).

[0033] Please continue to refer to Figure 2 , in some embodiments, the soft start module 120 further includes a release element Q2, which is connected to the energy storage element C1, and the release element Q2 is used to respond to the cutoff signal and release the energy stored in the energy storage element C1.

[0034] When the switch module Q1 needs to be turned off, the driving module 110 outputs a turn-off signal to reduce the gate voltage of the switch module Q1 to a low value, and at the same time makes the release element Q2 conduct, so as to further discharge the energy stored in the energy storage element C1, so that the turn-off of the switch module Q1 is not affected by the energy stored in the energy storage element C1 during the conduction of the switch module Q1, so that the energy storage element C1 can start charging again from the 0-voltage state during the next soft start, without affecting the next soft start.

[0035] Please continue to refer to Figure 2 , in some embodiments, the release element Q2 includes a first switching tube, the first switching tube is connected in parallel with the energy storage element C1, and the controlled end of the first switching tube is connected to the controlled end of the switch module Q1. The first switching tube conducts in response to the turn-off signal and quickly discharges the energy stored in the energy storage element C1.

[0036] For example, the first switching tube is a PNP type triode. After the switch module Q1 receives the turn-off signal, the gate of the switch module Q1 discharges to a low level, further causing the base level of the first switching tube to be lower than the emitter level, so that it conducts, forming an energy consumption loop with the energy storage element C1, thereby releasing the energy of the energy storage element C1, so that the turn-off of the switch module Q1 is not affected by the energy stored in the energy storage element C1 during the conduction of the switch module Q1, nor does it affect the next soft start.

[0037] Optionally, the base of the PNP type triode is connected to the controlled end of the switch module Q1 through a current limiting resistor R1.

[0038] Please continue to refer to Figure 2 , in some embodiments, the soft start module 120 further includes a unidirectional conduction element D1, and the unidirectional conduction element D1 is connected in series in the forward direction between the controlled end of the switch module Q1 and the energy storage element C1.

[0039] The unidirectional conduction element D1 is used to prevent the energy on the energy storage element C1 from flowing back to the controlled end of the switch module Q1 when the driving module 110 outputs a turn-off signal, that is, a low level, resulting in the failure of the switch module Q1 to turn off. The unidirectional conduction element D1 is, for example, a diode.

[0040] Please refer to Figure 1 and Figure 2 , in some embodiments, the driving module 110 includes a driving unit 112, a turn-off unit 113 and a switching unit 114.

[0041] The input end of the driving unit 112 is connected to the power input end of the power supply transmission line, the output end of the driving unit 112 is connected to the controlled end of the switch module Q1, and the driving unit 112 is used to output a conduction signal based on the voltage of the power input end;

[0042] The shut-off unit 113 is used to receive the detection signal and output a shut-off control signal in response to the detection signal being greater than a threshold value;

[0043] The control end of the switch unit 114 is connected to the shutdown circuit. The first conduction end of the switch unit 114 is connected to the controlled end of the switch module Q1. The second conduction end of the switch unit 114 is grounded. The switch unit 114 is turned on in response to the shutdown control signal.

[0044] The driving unit 112, for example, adopts a Wilson current mirror circuit to generate a high-level on signal based on the voltage at the power input terminal. The shutoff unit 113, for example, includes at least one comparator to compare the input detection signal with the corresponding threshold, thereby outputting or not outputting a shutoff control signal according to the comparison result. After the switch unit 114 is turned on in response to the shutoff control signal, the controlled end of the switch module Q1 is grounded, which is equivalent to providing a shutoff signal to the controlled end of the MOS tube.

[0045] See also Figure 2 In some embodiments, the switch unit 114 includes a first resistor R2, a second resistor R3, a first capacitor C2, and a second switch tube Q3; the first resistor R2 is connected between the shutoff unit 113 and the controlled end of the second switch tube Q3; the first end of the first capacitor C2 is connected to the controlled end of the second switch tube Q3, and the second end is grounded; the first conduction end of the second switch tube Q3 is connected to the controlled end of the switch module Q1, and the second conduction end is grounded through the second resistor R3. The second switch tube Q3 is, for example, an NPN transistor.

[0046] See also Figure 2 In some embodiments, the soft start circuit further includes a first detection module 130, which is connected to the power transmission line and the shutdown unit 113. The first detection module 130 is used to detect the power parameters transmitted by the power transmission line and output a first detection signal Vs corresponding to the power parameters. The shutdown unit 113 is also used to output a shutdown control signal in response to the first detection signal Vs exceeding the power parameter threshold.

[0047] See also Figure 2 Exemplarily, the first detection module 130 includes a sampling resistor and a first differential amplifier, the sampling resistor is connected in series on the power transmission line, and the two input ends of the first differential amplifier are respectively connected to the two ends of the sampling resistor, so as to detect the transmission current transmitted by the power transmission line, so the first detection signal Vs is a signal carrying the transmission current. The shutdown unit 113 compares the first detection signal Vs with the current reference signal representing the current threshold, and when the first detection signal Vs is greater than the current reference signal, that is, when overcurrent occurs, the shutdown control signal is output to control the switch unit 114 to turn on, and the switch module Q1 is turned off to achieve overcurrent protection.

[0048] In some embodiments, the soft-start circuit further includes a second detection module 140. The second detection module 140 is connected to the switch module Q1 and the turn-off unit 113. The second detection module 140 is configured to detect the voltage drop across the switch module Q1 and output a second detection signal Vds corresponding to the voltage drop. The turn-off unit 113 is further configured to output a turn-off control signal in response to the second detection signal Vds exceeding the voltage threshold.

[0049] Exemplarily, the second detection module 140 includes a second differential amplifier. The two input terminals of the second differential amplifier are respectively connected to the source and drain of the switch module Q1, so as to detect the voltages of the source and drain of the switch module Q1. Therefore, the second detection signal Vds is a signal carrying the voltages of the source and drain of the switch module Q1. The turn-off unit 113 compares the second detection signal Vds with a voltage reference signal representing the voltage threshold. When the second detection signal Vds is greater than the voltage reference signal, that is, when overvoltage occurs in the switch module Q1, the turn-off unit 113 outputs a turn-off control signal to control the switch unit 114 to conduct and control the switch module Q1 to turn off, thereby implementing overvoltage protection.

[0050] In a second aspect, an embodiment of the present application further provides an electronic device, including the above soft-start circuit.

[0051] The above electronic device is provided with a soft-start circuit. By connecting the soft-start module 120 to the controlled terminal of the switch module Q1, the conduction signal for driving the switch module Q1 to conduct can be shunted, thereby reducing the voltage rise speed of the controlled terminal of the switch module Q1, slowing down the turn-on speed of the switch module Q1, and further reducing the inrush current. In this way, without increasing the cost of the switch module Q1, the inrush current is reduced to protect the safety of the electronic device.

[0052] The above-described embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A slow start circuit, characterized in that: include: A switch module, used for being connected in series with a power transmission line; A driving module, connected to the controlled end of the switch module, and configured to output an on signal or an off signal to the controlled end of the switch module to drive the switch module to be on or off; The slow start module is connected to the controlled end of the switch module and is used to shunt the conduction signal and reduce the voltage rising speed of the controlled end of the switch module to slow down the switching speed of the switch module.

2. The slow start circuit according to claim 1, characterized in that: The soft start module includes an energy storage element, and the energy storage element is used for charging to shunt the conduction signal.

3. The slow start circuit according to claim 2, characterized in that: The soft start module further includes a release element connected to the energy storage element, and the release element is used to release the energy stored in the energy storage element in response to the shutdown signal.

4. The slow start circuit according to claim 2, characterized in that: The slow start module further comprises a unidirectional conductive element, which is connected in series in a forward direction between the controlled end of the switch module and the energy storage element.

5. The slow start circuit according to claim 3, characterized in that: The release element includes a first switch tube, which is connected in parallel with the energy storage element, and a controlled end of the first switch tube is connected to a controlled end of the switch module, and the first switch tube is turned on in response to the shutdown signal.

6. The slow start circuit according to any one of claims 1 to 5, characterized in that: The driving module comprises: A driving unit, the input end of which is connected to the power input end of the power transmission line, the output end of which is connected to the controlled end of the switch module, the driving unit being used to output the conduction signal based on the voltage of the power input end; A shut-off unit, for receiving a detection signal and outputting a shut-off control signal in response to a detection signal greater than a threshold value; A switch unit, a control end connected to the shutdown circuit, a first conduction end connected to the controlled end of the switch module, a second conduction end grounded, and the switch unit is turned on in response to the shutdown control signal.

7. The slow start circuit according to claim 6, characterized in that: It also includes a first detection module, which is connected to the power transmission line and the shutdown unit. The first detection module is used to detect the power parameter transmitted by the power transmission line and output a first detection signal corresponding to the power parameter. The shutdown unit is also used to output the shutdown control signal in response to the first detection signal exceeding the power parameter threshold.

8. The slow start circuit according to claim 6, characterized in that: It also includes a second detection module, which is connected to the switch module and the shutdown unit. The second detection module is used to detect the voltage drop across the switch module and output a second detection signal corresponding to the voltage drop across the two ends. The shutdown unit is also used to output the shutdown control signal in response to the second detection signal exceeding the voltage threshold.

9. The slow start circuit according to claim 6, characterized in that: The switch unit includes a first resistor, a second resistor, a first capacitor and a second switch tube; The first resistor is connected between the shutdown unit and the controlled end of the second switch tube; the first end of the first capacitor is connected to the controlled end of the second switch tube, and the second end is grounded; the first conduction end of the second switch tube is connected to the controlled end of the switch module, and the second conduction end is grounded through the second resistor.

10. An electronic device, characterized in that: The invention comprises a slow start circuit as claimed in any one of claims 1 to 9.

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