CN111446706B - Power supply protection method and device - Google Patents
Power supply protection method and device Download PDFInfo
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- CN111446706B CN111446706B CN202010289266.8A CN202010289266A CN111446706B CN 111446706 B CN111446706 B CN 111446706B CN 202010289266 A CN202010289266 A CN 202010289266A CN 111446706 B CN111446706 B CN 111446706B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
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Abstract
The application discloses a power supply protection method and a device, wherein the method comprises the following steps: under the condition that the power switch is turned on, adjusting the current value of the output current of the power switch to a specified current value through a current limiting function; the specified current value is smaller than a normal current value which can be output by the power switch; detecting whether the voltage of the output end of the power switch is larger than a reference voltage or not, and determining whether to turn off the power switch or not according to a detection result; and the voltage at the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value.
Description
Technical Field
The present application relates to the field of electronic technologies, and in particular, to a power protection method and apparatus.
Background
In the related art, the power switch can solve the problem of hot melting caused by capacitor short circuit or tube short circuit on the switch, but the scheme has some defects, for example, even if the switch circuit or the input capacitor and other parts are short-circuited in work, a user does not know what kind of fault occurs, the user can try to repeatedly power on and start up, parts damaged by power on at each time can experience a large current impact again, and equipment can experience a large current and high voltage impact again, so that secondary damage can be caused. How to avoid the above-mentioned situation becomes a problem to be solved.
Disclosure of Invention
The present application provides a power protection method and apparatus to solve the above problems in the prior art.
The application provides a power supply protection method, which comprises the following steps:
under the condition that the power switch is turned on, adjusting the current value of the output current of the power switch to a specified current value through a current limiting function; the specified current value is smaller than a normal current value which can be output by the power switch;
detecting whether the voltage of the output end of the power switch is greater than a reference voltage, and determining whether to turn off the power switch according to a detection result; and the voltage of the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value.
The application provides a power protection device, the device includes:
the current limiting unit is used for adjusting the current value of the output current of the power switch to a specified current value through a current limiting function under the condition that the power switch is turned on; wherein the specified current value is smaller than a current value which can be output by the power switch;
the comparator is used for detecting whether the voltage of the output end of the power switch is larger than the reference voltage or not and determining whether the power switch is turned off or not according to the detection result; and the voltage at the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value.
By adopting the scheme, under the condition that the power switch is turned on, the power switch is limited to the specified current value lower than the normal current value through the current limiting function, and then the voltage of the output end is detected to determine whether to turn off the power switch. Therefore, the control can not be successfully electrified under the condition that the output voltage and the reference voltage of the power switch meet certain conditions, so that the equipment can be protected from secondary damage to the maximum extent.
Drawings
Fig. 1 is a first schematic flow chart of a power protection method according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a hardware component structure provided in an embodiment of the present application;
FIG. 3 is a schematic diagram of a current limiting circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic flow chart of a power protection method according to an embodiment of the present application;
FIG. 5 is a schematic view of a processing effect of the solution provided by the embodiment of the present application;
fig. 6 is a schematic view of a processing scenario provided in an embodiment of the present application;
FIG. 7 is a diagram illustrating processing effects of an embodiment of the present application and related techniques;
fig. 8 is a schematic structural diagram of a power protection device according to an embodiment of the present application.
Detailed Description
In order to make the objects, features and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
An embodiment of the present application provides a power protection method, as shown in fig. 1, the method includes:
step 11: under the condition that the power switch is turned on, adjusting the current value of the output current of the power switch to a specified current value through a current limiting function; wherein the specified current value is smaller than a normal current value which can be output by the power switch;
step 12: detecting whether the voltage of the output end of the power switch is smaller than a reference voltage, and determining whether to turn off the power switch according to a detection result; and the voltage of the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value.
The application scenario of this embodiment may be any device that needs to be controlled by a power switch to supply power, for example, the application scenario may be any electronic device such as a PC, a notebook, and a tablet, which is not exhaustive. Specifically, the scheme provided by this embodiment may be applied to the power switch of the above-mentioned device to control the power-on or power-off of the power switch.
In step 11, the Power Switch (Power Switch) is turned on, which may be understood as that when a Power Switch button is pressed when an electronic device (such as a PC (personal computer)) is powered on, the Power Switch is turned on.
When the power switch presses the start key, the voltage of the input end of the power switch is established; here, as can be explained with reference to fig. 2, the voltage build-up at the input terminal refers to the build-up of Vin, i.e., the voltage at the input terminal, when Q1 (power switch) is turned on in the figure.
In addition, in step 11, the current value of the output current of the power switch is adjusted to the specified current value by the current limiting function, which means that the power switch is not directly turned On completely (Turn On) to avoid generating a large current, but the gate of the field effect transistor (MOS) of the power switch is turned On slightly by the current limiting function of the current limiting (current limit) line, and the current flowing On the power switch is limited to a specified value.
The specified current value can be set according to actual conditions, and the range of the specified current value can be 1-100mA. For example, the current may be 10mA, but may also be smaller or slightly larger, as long as the current is lower than the normal current value that can be output by the power switch, and this embodiment is not exhaustive.
That is, the current limiting function can be realized by providing a current limiting circuit, which functions (or circuits) to enable the output current of the power switch to be lower than the normal current value that can be output.
There may be a plurality of ways for implementing the current limiting function or circuit, and this embodiment is not illustrated, but only illustrated by an example, for example, a way of using mirror current sampling may be used, and specifically, as shown in fig. 3:
the power switch itself is a MOSFET module (e.g. Q1 in the figure) with a large wafer composed of a plurality of MOSFET cells, and this MOSFET is a current main loop, which bears a large current, and is not easy to sample the current (the series resistance causes a large power loss), and another MOSFET (e.g. Q2 in the figure) is generally made in equal proportion as a mirror image, and this MOSFET (e.g. Q2 in the figure) can mirror the current of the power switch MOSFET (e.g. Q1 in the figure), wherein the current of the power switch MOSFET (e.g. Q1 in the figure) can be represented as I1 in the figure, and the mirrored current of another MOSFET (e.g. Q2 in the figure) is represented as I2 in the figure; the current I2 flowing through the Q2 is reduced according to the proportion K, so that the current can be sampled by using a resistor; the method may further include controlling the gate conduction level by a feedback loop to ensure that the sampling current (I2) is the same as the set current limit current (i.e., the specified current value).
It should be noted that this example is only one implementation of the current limiting circuit, and other implementations may exist in practice, and this embodiment is not exhaustive, and a circuit that can obtain a specified current value smaller than the original output current is within the protection scope of the present application.
In step 12, it is detected whether the voltage at the output end of the power switch is smaller than the reference voltage, specifically, the voltage at the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value. Whether the output end has a problem is determined through comparison between the voltage of the output end of the power switch and a reference voltage, and the obtained detection result is the relative relation between the voltage of the output end and the reference voltage, so that whether the output end has the problem is indicated.
Further, the output end has a problem, which can be understood as that the output end has a short circuit problem;
the occurrence of short-circuit problems, which may be due to damage to components, such as short-circuiting of input capacitors, or short-circuiting of upper tubes of a switching circuit, etc., is not exhaustive here.
Specifically, if no part is damaged at the output end, the impedance of the output end is generally greater than 1K, so the output end voltage (10ma × 1k) of the power switch is generally greater than the reference voltage;
if the output terminal components are damaged and shorted, for example, the input capacitor is shorted, or the upper tube of the switch circuit is shorted, the impedance of the output terminal is very low, which is between several ohms and several tens of ohms, and at this time, the output terminal voltage of the power switch, for example, may be equal to 10ma × 10ohm, which is necessarily less than the reference voltage.
The reference voltage may be set according to actual conditions, and may be, for example, 1 volt (V).
In step 12, the determining whether to turn off the power switch according to the detection result may include the following processing conditions:
situation one,
And if the detection result indicates that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch.
In the first case, it can be considered that, as long as the detection is performed at any time point, and the obtained detection result indicates that the voltage of the output terminal of the power switch is not greater than the reference voltage, it can be considered that a problem (such as the above short circuit problem) exists at the output terminal, and at this time, the power switch can be immediately turned off, which is relatively fast in processing and relatively high in efficiency.
The second condition,
And if the detection results obtained within the preset time period all represent that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch.
In the second case, the detection result at any time point represents that the voltage of the output end of the power switch is not greater than the reference voltage, and timing can be performed;
if the voltage of the output end of the power switch is detected to be greater than the reference voltage in the timing process, judging whether the current timing time is less than the preset time, if so, stopping timing, and not turning off the power supply. At this time, there may be two ways for the subsequent processing, and in one way, the current limiting function may be kept turned on until it is no longer detected after a period of time that the voltage of the output terminal of the power switch is not greater than the reference voltage, and then it may be determined that the output terminal is normal, and then the subsequent turning-on processing is normally performed. In another mode, the output end can be directly determined to be normal, and subsequent opening processing is carried out.
If the detection results of each time are consistent in the process of starting timing and till the timing time reaches the preset time, the voltage of the output end of the power switch is represented to be not more than the reference voltage, the output end is determined to be abnormal (or have a problem), and the power switch is determined to be turned off.
In the second case, a timer may be added, the timing duration of which is equal to the preset duration, and the timing is started once any detection result indicating that the voltage at the output end of the power switch is not greater than the reference voltage is detected, and is defined as keeping the timing if the same detection result is detected again (that is, also indicating that the voltage at the output end of the power switch is not greater than the reference voltage), and stopping the timing of the timer if a different detection result is detected (that is, indicating that the voltage at the output end of the power switch is greater than the reference voltage).
That is to say, in the second case, the detection result within a period of time is used as the judgment basis, and this way can avoid the situation of misjudgment, so that the second case is more accurate.
The third condition,
And if the detection result indicates that the voltage of the output end of the power switch is greater than the reference voltage, determining not to turn off the power switch.
That is, after the detection is started, if the detection result representing that the voltage of the output end of the power switch is larger than the reference voltage at any time is detected, the power switch is determined not to be turned off;
or after the detection is started, if the voltage of the output end of the first detection result representing the power switch is larger than the reference voltage, determining not to close the power switch;
or, in combination with the duration, after the detection is started, if the detection result indicates that the voltage of the output end of the power switch is greater than the reference voltage within the duration, it is determined not to turn off the power switch.
Further, when it is determined not to turn off the power switch, the method further includes:
triggering a soft start circuit and canceling a current limiting function of the current limiting unit; the soft start circuit is used for controlling the power switch to be normally started so as to output current with a normal current value.
That is, if it is determined that the power switch is not turned off, the electronic device (such as a PC, a notebook, etc.) using the scheme provided in this embodiment may perform subsequent processing according to a normal power-on procedure, which is not described herein again.
In an example, with reference to fig. 4, a flow of the scheme provided in this embodiment is described:
step 41, inserting a power supply into a computer, and establishing the voltage of an input end of a power switch (power switch);
step 42: the power switch is turned on, and a current limit function is activated to limit the output current of the power switch to a specified current value, for example, 10mA. Wherein the power switch may be turned on slowly.
43, detecting the voltage of the output end of the power switch;
and step 44, judging whether the voltage of the output end is greater than the reference voltage, if so, executing step 45, otherwise, executing step 46.
For example, an IC (integrated circuit) (e.g., a comparator) simultaneously detects the output voltage, and if there is no component damage at the output, the impedance at the output is generally greater than 1K, so that 10ma × 1k > the reference voltage (e.g., 1V), and if there is a component damage short at the output, such as a short circuit at the input capacitor, or a short circuit at the upper tube of the switching circuit, the impedance at the output is very low, ranging from several ohms to several tens of ohms, and 10ma < 10ohm < the reference voltage (e.g., 1V).
And step 45, triggering the soft start circuit, and normally outputting by the power switch.
Wherein, the normal output of the power switch at least can include: the current limiting function is cancelled by control, so that the power switch is ensured to output at least current with a normal current value.
And step 46, keeping the power off, and turning off the power switch when the duration reaches the preset duration.
Here, turning off the power switch may further include turning off the IC of the entire apparatus, which may include regarding a current-off limit current (or function), turning off a soft start circuit, and the like.
The above-mentioned keeping from being started refers to not normally starting the power switch, and further, it can be understood as keeping from being started by the soft start circuit.
In combination with the above steps 45 and 46, that is, when the output voltage is detected to be greater than the reference voltage (e.g. 1V), the soft-start circuit is activated to enable the power switch to be normally turned on, and when the output voltage is detected to be lower than the reference voltage (e.g. 1V), the power switch (power switch) is completely turned off after a period of time (e.g. 10 ms) (to ensure the false detection).
With reference to fig. 5, a comparison graph of waveforms of normal power-up of the output impedance and abnormal power-up of the output impedance is shown:
output impedance is normally on (impedance is normal): the computer is plugged into a Power supply at the time of T1, the voltage of the Vin input end of the Power switch is built up at the time, the output voltage Vo of the Power switch starts to climb, the output current is limited to 10mA, the climbing is slow, the Vo climbs to be 1V higher than the set reference voltage at the time of T2, the current limiting currentlimit function is released, the soft start soft-start is started, and the voltage normally climbs to Vo = Vin
Output impedance anomaly power up (impedance anomaly): the computer is plugged into a power supply at the time of T1, the voltage of the input end Vin of the power switch is built, the power switch is slowly turned on at the time, the output current is limited to 10mA, the output voltage cannot climb because of low output impedance, is kept at 10mA output impedance and cannot be higher than the reference voltage all the time, and is still not higher than the reference voltage after lasting for a period of time T, and the IC completely turns off the power switch.
In summary (see also fig. 2), the basic logic of the scheme is: when a part in the system is burnt out, such as an input capacitor or a switch tube, the impedance of a system voltage input end is very low, so that when the system is powered on, a power switch is not directly and completely turned on so as to avoid generating large current, a gate pole of an MOS (metal oxide semiconductor) of the power switch is slightly conducted by using a current limiting current limit circuit (or function), and the current flowing on the power switch is limited to a specified current value (the range can be 1-100 mA), for example, 10mA, and the 10mA current can charge a capacitor at a Vsys end (output end) to a capacitor at the Vsys end (output end)Electrically, if the impedance of the Vsys terminal (output terminal) is normal, the voltage at the Vsys terminal (output terminal) will quickly build up to exceed a threshold value, i.e. a reference voltage (such as the reference voltage V of the comparator in the figure), which is a reference voltage REF ) For example, 1V, at this time, the current limiting function is cancelled and the soft-start function is started to make the power switch soft start successful;
if the impedance of the Vsys end (output end) is abnormal (low), the voltage on the Vsys end cannot be established, the comparator detects that the output voltage is low, the power switch is not enabled to be in soft start all the time, no voltage appears at the Vsys end (output end), the current is limited to a very low value, the generated power is very low, originally good parts such as a CPU (central processing unit), a memory and the like cannot be burnt by mistake, originally damaged parts cannot be damaged or aggravated, and the analysis can be facilitated.
As shown in fig. 6, if Q1 in the switch circuit is short-circuited, a large current will reach the device end through Q1- > L1, because the device is usually low impedance, a loop is formed, and the large current will flow through the device to cause device damage, while the solution provided by the present application uses a small current to detect the impedance of the loop before the device is turned on, and the small current will not cause any damage to the device.
The reliability of the power switch can be improved, because when the conventional power switch is powered on (turned on), if a back-end system power supply loop is in a short-circuit state, the current flowing through the power switch can be rapidly increased, although the power switch can perform a current limiting action, because the voltage difference between two ends of the power switch is very large (the input end is equal to Vin voltage, and the output end is equal to Vin because of the short-circuit of the power supply loop, and the voltage is zero), the power switch has very large power consumption, for example, as shown in fig. 7, in the related art, the power switch is used on a 20V input product, and the current protection point set by the power switch is 20A, when a short circuit occurs at the system end, the instantaneous power switch has instantaneous power consumption of 20 × 20 400w above the power switch, and the instantaneous power consumption can cause the power switch to be burned instantly, even if the power switch is not burned at one time, if a user does not know the situation, the power switch repeatedly tries to be burned, so that the reliability is very high.
By adopting the scheme provided by the application, if a short-circuit condition occurs in the rear-end line of the power switch, the current on the power switch is limited to a very small current, which does not cause any damage to the power switch, for example, as shown in fig. 7, the current is kept at 10mA, and the generated voltage is 10ma × 20v =0.2w, so that the reliability problem does not occur.
Therefore, by adopting the scheme, under the condition that the power switch is turned on, the power switch is limited to the specified current value lower than the normal current value through the current limiting function, and then the voltage of the output end is detected to determine whether to turn off the power switch. Therefore, the control can not be successfully electrified under the condition that the output voltage and the reference voltage of the power switch meet certain conditions, so that the equipment can be protected from secondary damage to the maximum extent.
An embodiment of the present application provides a power protection apparatus, as shown in fig. 8, including:
a current limiting unit 81 for adjusting a current value of an output current of the power switch to a specified current value by a current limiting function in a case where the power switch is turned on; wherein the specified current value is smaller than a current value which can be output by the power switch;
a comparator 82 for detecting whether the voltage at the output terminal of the power switch is greater than a reference voltage, and determining whether to turn off the power switch according to the detection result; and the voltage at the output end of the power switch is established by charging the capacitor at the output end based on the output current of the power switch with the specified current value.
The application scenario of this embodiment may be any device that needs to be controlled by a power switch to supply power, for example, the device may be an electronic device such as a PC, a notebook, and a tablet, which is not exhaustive. Specifically, the apparatus provided in this embodiment may be applied to a power switch of the above-mentioned device to control power-on or power-off of the power switch.
And a comparator 82, configured to detect whether an output voltage of the power switch is smaller than a reference voltage, specifically, the output voltage of the power switch is established by charging an output capacitor with the output current of the power switch based on the specified current value. Whether the output end has a problem is determined through comparison between the voltage of the output end of the power switch and a reference voltage, and the obtained detection result is the relative relation between the voltage of the output end and the reference voltage, so that whether the output end has the problem is indicated.
Further, the output end has a problem, which can be understood as that the output end has a short circuit problem;
the occurrence of short-circuit problems, which may be due to damage to components, such as short-circuiting of input capacitors, or short-circuiting of upper tubes of a switching circuit, etc., is not exhaustive here.
The comparator 82, which is used to determine whether to turn off the power switch according to the detection result, may include the following processing conditions:
situation one,
And if the detection result indicates that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch.
In the first case, it can be considered that, as long as the detection is performed at any time point, and the obtained detection result indicates that the voltage of the output terminal of the power switch is not greater than the reference voltage, it can be considered that a problem (such as the above short circuit problem) exists at the output terminal, and at this time, the power switch can be immediately turned off, which is relatively fast in processing and relatively high in efficiency.
The second case,
And if the detection results obtained within the preset time period all represent that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch.
In the second case, it can be considered that the detection result at any time point indicates that the voltage of the output end of the power switch is not greater than the reference voltage, and then timing can be performed;
if the voltage of the output end of the power switch is detected to be greater than the reference voltage in the timing process, judging whether the current timing duration is less than the preset duration, if so, stopping timing and not turning off the power supply. At this time, there may be two ways for the subsequent processing, and in one way, the current limiting function may be kept on until it is no longer detected after a period of time that the voltage of the output terminal of the power switch is not greater than the reference voltage, and then it may be determined that the output terminal is normal, and then the subsequent start-up processing is performed normally. In another mode, the output end can be directly determined to be normal, and subsequent starting processing is carried out.
If the detection results of each time are consistent in the process of starting timing and till the timing time reaches the preset time, the voltage of the output end of the power switch is represented to be not more than the reference voltage, the output end is determined to be abnormal (or have a problem), and the power switch is determined to be turned off.
In the second case, a timer may be added, the timing duration of which is equal to the preset duration, and the timing is started once any detection result indicating that the voltage at the output end of the power switch is not greater than the reference voltage is detected, and is defined as keeping the timing if the same detection result is detected again (that is, also indicating that the voltage at the output end of the power switch is not greater than the reference voltage), and stopping the timing of the timer if a different detection result is detected (that is, indicating that the voltage at the output end of the power switch is greater than the reference voltage).
That is to say, in the second case, the detection result within a period of time is used as the judgment basis, and this way can avoid the situation of misjudgment, so that the second case is more accurate.
The third condition,
And if the detection result represents that the voltage of the output end of the power switch is greater than the reference voltage, determining not to close the power switch.
That is, after the detection is started, if the detection result representing that the voltage of the output end of the power switch is larger than the reference voltage at any time is detected, the power switch is determined not to be turned off;
or after the detection is started, if the voltage of the output end of the first detection result representing the power switch is larger than the reference voltage, determining not to close the power switch;
or, by combining the duration, after the detection is started, if the detection result indicates that the voltage of the output end of the power switch is greater than the reference voltage within the duration, it is determined not to turn off the power switch.
Further, the apparatus further comprises:
a soft start circuit 83 for controlling the power switch to be normally turned on to output a current of a normal current value;
the comparator 82 is further configured to trigger the soft start circuit and cancel the current limiting function of the current limiting unit when it is determined that the power switch is not turned off.
The current limiting function of the current limiting unit that the comparator determines to cancel can be controlled by an Enable (EN), for example, setting the current limiting function to a high potential can indicate enabling, and setting the current limiting function to a low point can indicate not enabling (that is, canceling), or vice versa, and details are not repeated; the comparator and the triggering soft start circuit can also control the potential of the enabling tube angle of the current through corresponding enabling control, for example, high potential indicates enabling, otherwise, indicates disabling, or vice versa, and thus, detailed description is omitted.
In summary (see also fig. 2), the basic logic of the scheme is: when parts in a system are burnt, such as an input capacitor or a switch tube, the impedance of a voltage input end of the system is very low, so that when the system is powered on, a power switch is not directly and completely switched on so as to avoid generating large current, a gate pole of an MOS (metal oxide semiconductor) of the power switch is conducted slightly by using a current limiting circuit, the current flowing through the power switch is limited to be a specified current value, the current can charge a capacitor at a Vsys end (output end), if the impedance of the Vsys end (output end) is normal, the voltage at the Vsys end (output end) can be quickly established to exceed a threshold value, and at the moment, a comparator can compare the voltage at the output end with a reference voltage (Vref in a figure) to determine whether the current limiting function is cancelled or not and start a soft start-start function to ensure that the power switch is successfully soft started;
if the impedance of the Vsys end (output end) is abnormal (low), the voltage on the Vsys end cannot be established, the comparator detects that the voltage of the output end is low and the reference voltage, the control is not enabled, namely, the soft start circuit is not enabled all the time, no voltage appears on the Vsys end (output end), the current is limited to a very low value, the generated power is very small, originally good parts such as a CPU (central processing unit), a memory and the like cannot be burnt by mistake, originally damaged parts cannot be damaged or aggravated, and the analysis can be facilitated.
Therefore, by adopting the scheme, under the condition that the power switch is turned on, the power switch is limited to the specified current value lower than the normal current value through the current limiting function, and then the detection of the voltage of the output end is carried out to determine whether to turn off the power switch. Therefore, the control can not be successfully electrified under the condition that the output voltage and the reference voltage of the power switch meet certain conditions, so that the equipment can be protected from secondary damage to the maximum extent.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (6)
1. A method of power supply protection, the method comprising:
under the condition that the power switch is turned on, adjusting the current value of the output current of the power switch to a specified current value through a current limiting function; wherein the specified current value is smaller than a normal current value which can be output by the power switch;
detecting whether the voltage of the output end of the power switch is greater than a reference voltage, and determining whether to turn off the power switch according to a detection result; when the power supply is powered on, the power switch is not directly and completely turned on so as to avoid generating large current, but the gate pole of the power switch is conducted slightly by using the current limiting function, and the current flowing on the power switch is limited within a specified current value, and at the moment, the current flowing on the power switch can charge the output end capacitor; the voltage of the output end of the power switch is established by charging a capacitor at the output end based on the output current of the power switch with the specified current value;
the specified current value is more than or equal to 1mA and less than or equal to 100mA;
wherein whether to close the power switch is determined according to the detection result, comprising:
if the detection result indicates that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch and keeping the current limiting function;
determining whether to turn off the power switch according to the detection result, including:
and if the detection result indicates that the voltage of the output end of the power switch is greater than the reference voltage, determining not to close the power switch, and canceling the current limiting function.
2. The method of claim 1, wherein determining whether to turn off the power switch according to the detection result comprises:
and if the detection results obtained within the preset time period all represent that the voltage of the output end of the power switch is not greater than the reference voltage, determining to close the power switch.
3. The method of claim 1, wherein upon determining not to turn off the power switch, the method further comprises:
triggering a soft start circuit and canceling the current limit function; the soft start circuit is used for controlling the power switch to be normally started so as to output current with a normal current value.
4. A power supply protection device, the device comprising:
the current limiting unit is used for adjusting the current value of the output current of the power switch to a specified current value through a current limiting function under the condition that the power switch is turned on; wherein the specified current value is smaller than a current value which can be output by the power switch;
the comparator is used for detecting whether the voltage of the output end of the power switch is larger than the reference voltage or not and determining whether the power switch is turned off or not according to the detection result; when the power supply is powered on, the power switch is not directly and completely turned on so as to avoid generating large current, but the gate pole of the power switch is conducted slightly by using the current limiting function, and the current flowing on the power switch is limited within a specified current value, and at the moment, the current flowing on the power switch can charge the output end capacitor; the voltage of the output end of the power switch is established by charging a capacitor at the output end based on the output current of the power switch with the specified current value;
the comparator is specifically configured to determine to turn off the power switch and maintain the current limiting function if the detection result indicates that the voltage at the output end of the power switch is not greater than the reference voltage;
the comparator is specifically configured to determine not to turn off the power switch and cancel the current limiting function if the detection result indicates that the voltage at the output end of the power switch is greater than the reference voltage.
5. The apparatus of claim 4,
the comparator is specifically configured to determine to turn off the power switch if the detection results obtained within the preset time period all indicate that the voltage at the output end of the power switch is not greater than the reference voltage.
6. The apparatus of claim 4, further comprising:
the soft start circuit is used for controlling the power switch to be normally started so as to output the current with the normal current value;
the comparator is also used for triggering the soft start circuit and canceling the current limiting function of the current limiting unit when the power switch is determined not to be turned off.
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| CN102437560B (en) * | 2011-12-20 | 2014-02-19 | 北京控制工程研究所 | Surge current suppression circuit module with recoverable over-current protection function |
| CN105529677A (en) * | 2015-12-01 | 2016-04-27 | 中国矿业大学(北京) | Current-limiting solid-state circuit breaker for actively suppressing overvoltage and control method thereof |
| CN106385018B (en) * | 2016-10-27 | 2019-04-23 | 华中科技大学 | A kind of short-circuit fault current limiter |
| CN107918426B (en) * | 2017-03-29 | 2020-09-11 | 汉颖科技股份有限公司 | Power supply device with soft start and protection functions |
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| CN209658957U (en) * | 2019-04-30 | 2019-11-19 | 苏州杰跃飞电子科技有限公司 | Twin load circuit driving protection control module |
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| CN1089043A (en) * | 1992-09-21 | 1994-07-06 | 株式会社东芝 | Power transistor overcurrent protection circuit |
| CN1292603A (en) * | 1999-09-27 | 2001-04-25 | 松下电工株式会社 | Optical response semiconductor switch with short circuit load protection |
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