CN115395935A - High-side switch circuit with self-diagnosis function - Google Patents
High-side switch circuit with self-diagnosis function Download PDFInfo
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- CN115395935A CN115395935A CN202211168166.5A CN202211168166A CN115395935A CN 115395935 A CN115395935 A CN 115395935A CN 202211168166 A CN202211168166 A CN 202211168166A CN 115395935 A CN115395935 A CN 115395935A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
- H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0063—High side switches, i.e. the higher potential [DC] or life wire [AC] being directly connected to the switch and not via the load
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0081—Power supply means, e.g. to the switch driver
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Abstract
The invention belongs to the technical field of high-side power output control, and particularly relates to a high-side switch circuit with a self-diagnosis function. Through setting up the high limit switch circuit including self-diagnosing circuit, can realize opening before the high limit switch circuit, to the load preliminary diagnosis to when the load is inductive load or capacitive load, carry out the preliminary filling and handle, with reduce the electric current impact when opening the high limit switch, and then avoided opening the too big phenomenon of electric current of high limit switch circuit in the twinkling of an eye because of load reason causes, and then avoided the problem of overcurrent fault protection.
Description
Technical Field
The invention belongs to the technical field of high-side power output control, and particularly relates to a high-side switch circuit with a self-diagnosis function.
Background
The high-side switch in the high-side switch circuit generally uses a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), which has the advantages of small on-resistance, no electric spark, small volume and the like, and is widely applied to automobile parts to replace the traditional relay circuit. In order to prevent the MOSFET from being damaged in a fault mode, a semiconductor manufacturer uses the MOSFET to combine with circuits such as short-circuit protection, over-current protection, over-temperature protection and the like to be uniformly packaged to manufacture the high-side switch, so that the high-side switch immediately starts a self-protection function and closes an output channel when the current or the temperature exceeds a threshold value. Under normal conditions, the protection mechanism can effectively protect the high-side switch from being burnt by short-circuit current, but when capacitive load or inductive load is driven, because the impact current is too large when the rear-end load is started, the protection threshold of the high-side switch is easily broken through, and the overcurrent protection of the high-side switch is triggered, so that the load cannot be started normally. In addition, the high-side switch is turned on under the condition of short circuit of the load circuit, even if the protection mechanism has effective protection function and can turn off the MOSFET, the short-circuit impact current causes irreversible damage to the MOSFET, the service life of the high-side switch is seriously influenced, and when the short-circuit capacity is large enough, the high-side switch can be directly damaged even, so that the function of a vehicle is seriously disabled.
Aiming at the problem, the main solution in the industry at present is to adopt a plurality of high-side switches to be connected in parallel so as to use the high-side switches of other branches when the high-side switch of one branch fails to enhance the output capability. However, this method has a disadvantage that it is difficult to overcome, and the protection performance after parallel connection is degraded due to the dispersion of the characteristics of the components.
Disclosure of Invention
The invention aims to provide a high-side switch circuit with a self-diagnosis function, which is used for solving the problem of error protection of a high-side switch control circuit with a protection function in the prior art.
In order to solve the technical problems, the invention provides a high-side switch circuit with a self-diagnosis function, which comprises a high-side switch and a control unit, wherein the high-side switch is arranged between a power supply and a load, the control unit is connected with the high-side switch in a control mode so as to control the on-off of the high-side switch, the high-side switch circuit also comprises a self-diagnosis circuit, the self-diagnosis circuit comprises a signal acquisition circuit and a driving circuit, the driving circuit comprises a driving switch and a current-limiting resistor which are serially connected between the power supply and the load and are connected with the high-side switch in parallel, and the driving switch is connected with the control unit; the acquisition circuit comprises a power end voltage detection port and a load end voltage detection port, the power end voltage detection port is connected to the control unit through the power end acquisition circuit, and the load end voltage detection port is connected to the control unit through the load end acquisition circuit;
the control unit is used for sending a diagnosis starting instruction to the driving switch when receiving the instruction of starting the high-side switch, performing diagnosis control on the driving switch, realizing the conduction or the blockage of the power supply of a circuit where the driving switch is located to a load, acquiring a power supply end voltage signal and a load end voltage signal after diagnosis starting, judging the load type according to the power supply end voltage signal and the load end voltage signal, and performing pre-charging treatment when the load type is an inductive load type or a capacitive load type so as to reduce current impact when the high-side switch circuit is started.
The beneficial effects are as follows: because the high-side switch circuit in the prior art has the overcurrent protection circuit, the high-side switch circuit comprising the high-side switch, the self-diagnosis circuit and the control unit is arranged, so that the load can be preliminarily diagnosed before the high-side switch circuit is started, and when the diagnosis result is an inductive load or a capacitive load, the pre-charging treatment of the corresponding load is required, so that no current impact exists when the high-side circuit is started.
Further, when the load type is an inductive load type or a capacitive load type, the pre-charging process is as follows: the control unit controls the conduction of a driving circuit of the self-diagnosis circuit for a set time.
When the load type is an inductive load type or a capacitive load type, the load is subjected to pre-charging processing to reduce the capacity of the load, so that the situation that the normal opening of the high-side switch circuit is influenced due to the existence of impact current when the high-side switch circuit is opened is avoided, the situation that the over-current protection circuit of the high-side switch circuit is subjected to error protection is avoided, and the cost of resetting the pre-charging circuit is avoided by performing the pre-charging processing through the driving circuit of the self-diagnosis circuit.
Further, the diagnostic control is: controlling the drive switch to be turned on for setting a first time, and then controlling the drive switch to be turned off for setting a second time; the power supply terminal voltage signal includes: mean value V of voltage signal at power supply end in first time period ad1 And the mean value V of the power supply terminal voltage signal in the second period ad4 (ii) a The load terminal voltage signal comprises a mean value V of the load terminal voltage signal in a first time period ad2 And the mean value V of the voltage signal at the load end in the second time period ad3 。
Because the voltage data when the circuit is opened and closed are different when the load types are different, the specific load types can be analyzed by collecting the voltage data when the diagnosis circuit is opened and closed, and carrying out average processing on the voltage data when the diagnosis circuit is opened and carrying out average processing on the voltage data when the diagnosis circuit is closed.
Further, the basis for determining the load type according to the power supply terminal voltage signal and the load terminal voltage signal is as follows:
if V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＞V min Judging the load to be capacitive load;
if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＞V diff Judging the load to be inductive load;
wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is the threshold value of the voltage difference between the two ends of the high-side switch.
Further, the load types further include an open circuit load type and a short circuit load type; when the load type is an open circuit load type or a short circuit load type, the control unit refuses to execute the command of opening the high-side switch and sends alarm information to the command sending unit of opening the high-side switch.
When external load short circuit or open circuit, namely external load has trouble, do not carry out the instruction of opening high limit switch circuit, and send external load trouble information to the order and issue the unit, can avoid when external load trouble, open high limit switch circuit, cause the harm to high limit switch circuit or load, and then the reliable process of control high limit switch circuit has been guaranteed, when having avoided having load short circuit among the prior art promptly, after opening high limit switch circuit, short-circuit rush current has led to the fact irreversible damage to MOSFET, the life of high limit switch is seriously influenced, when short circuit capacity is enough big, can directly destroy high limit switch even, lead to the vehicle function to seriously lose efficacy, and then when external load short circuit, the control unit refuses the order of outside opening high limit switch circuit, vehicle safety has been protected.
Further, the judgment basis of the open circuit load type and the short circuit load type is as follows:
if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＜V diff Judging that the load is open-circuit;
if V ad1 -V ad2 ＞V diff 、V ad2 ＜V min And V is ad3 ＜V min Judging that the load is short-circuited;
wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is a threshold value of voltage difference between two ends of the high-side switch, V ad1 To average value, V, of the voltage signal of the power supply terminal in the time period of conducting the drive switch ad2 To mean value of voltage signal at load terminal in time period of conducting drive switch, V ad3 For blocking the mean value of the voltage signal across the load terminal during the period of driving the switch, V ad4 When the switch is driven for blockingMean value of the supply terminal voltage signal over the time period.
Further, the load types also include a resistive load type; when the load type is a resistive load, the control unit executes a command of opening the high-side switch; the judgment basis of the resistive load type is as follows:
if V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＜V min Judging the load to be a resistive load; wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is a threshold value of voltage difference between two ends of the high-side switch, V ad1 To average value of voltage signal of power supply terminal in time period of on-drive switch ad2 To average value of voltage signal at load terminal in time period of conducting drive switch, V ad3 For blocking the mean value V of the voltage signal at the load terminal in the switching time period ad3 。
When the external load is a resistive load, no impact current exists when the high-side switch is turned on, so that the high-side switch can be directly turned on, namely, a command for turning on the high-side switch can be executed.
Furthermore, the driving switch comprises two triodes which are respectively a first switching tube and a second switching tube, an emitter and a collector of the first switching tube are respectively used for connecting a power supply end and a load end, and a base of the first switching tube is connected with a collector of the second switching tube; the emitting electrode of the second switch tube is used for grounding, and the base electrode of the second switch tube is connected with the control unit.
The control unit is connected to the control end of the second switch tube (namely the base electrode of the second switch tube), the on and off of the second switch tube can be controlled, the second switch tube is connected with the control end of the first switch tube, the on and off of the first switch tube are controlled through the on-off state of the second switch tube, the on and off of the first switch tube can be controlled through the control unit, the self-diagnosis process of the high-side switch circuit can be realized, compared with the mode that one switch tube is directly controlled to realize the on-off state of the self-diagnosis circuit, the two switch tubes are used, the state of the other switch tube is controlled through the state of one switch tube, and the control reliability is improved.
Drawings
FIG. 1 is a schematic diagram of the high-side switch circuit with self-diagnostic function of the present invention;
fig. 2 is a flowchart of a control method of the high-side switching circuit with self-diagnostic function of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
High-side switch circuit embodiment with self-diagnostic function:
the high-side switch circuit with the self-diagnosis function comprises a high-side switch, a self-diagnosis circuit and a control unit, wherein the high-side switch is a high-side switch circuit with an overcurrent protection circuit, the high-side switch is serially arranged between a power supply and a load and is used for conducting or blocking the power supply of the power supply to the load; the control unit is used for judging the load type after receiving the voltage signal at the power supply end and the voltage signal at the load end, and pre-charging the corresponding load when the load type is a capacitive load type or an inductive load type (the inductive load type and the capacitive load type do not refer to a pure inductor and a capacitor, but are equivalent circuits presented by a rear-end load circuit) so as to reduce current impact when the high-side switch circuit is started.
Through setting up the high limit switch circuit including high limit switch, self-diagnosis circuit and the control unit, can realize opening before the high limit switch circuit, carry out preliminary diagnosis to the load, and when the diagnostic result is inductive load or capacitive load, need carry out the preliminary treatment that corresponds the load, with no current impact when opening the high limit circuit, through the setting of this circuit, avoided when opening the high limit switch circuit, because of the too big phenomenon of the electric current of load reason cause opening the high limit switch circuit in the twinkling of an eye, and then avoided the problem of mistake protection.
As shown in fig. 1, the high-side switching circuit includes a third switching tube Q3, a fourth switching tube Q4, a resistor R6, a resistor R7, a resistor R8, and a resistor R9, and the specific connection relationship is as follows: the third switching tube Q3 is serially arranged between a power supply end and a load end, the resistor R6 is connected with a drain electrode and a grid electrode (namely a control end) of the third switching tube Q3, the grid electrode of the third switching tube Q3 is also connected to a drain electrode of the fourth switching tube Q4 through the resistor R11 so as to control the on-off of the third switching tube Q3 through the fourth switching tube Q4, the grid electrode (namely the control end) of the fourth switching tube Q4 is grounded through the resistor R9 and is connected to the control unit through the resistor R8 so as to transmit a control signal of the control unit to the control end of the fourth switching tube Q4, the fourth switching tube Q4 can make a switching state corresponding to the control signal transmitted by the control unit, and the switching state of the fourth switching tube Q4 is reflected to the control end of the third switching tube Q3 so as to realize the on-off control of the third switching tube Q3, and further realize the on-off control of a power supply input end and a power output end.
The self-diagnosis circuit comprises a first switch tube Q1 (PNP type triode), a second switch tube Q2 (NPN type triode), a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a resistor R10, and the specific connection relationship is as follows: the first switching tube Q1 is serially arranged between a power supply end and a load end (different from a branch of a third switching tube), a current limiting resistor R4 is further serially arranged between the first switching tube Q1 and the load end, the resistor R1 is connected with an emitter and a base of the first switching tube Q1 (the base of the first switching tube Q1 is the control end of the first switching tube Q1), the control end of the first switching tube Q1 is further connected to a collector of the second switching tube Q2 through a resistor R2 so as to realize on-off control of the first switching tube Q1 through the on-off state of the second switching tube Q2, the emitter of the second switching tube Q2 is grounded, the base of the second switching tube Q2 (namely the control end of the second switching tube Q2) is connected to the control unit through a resistor R3 so as to transmit the control signal of the control unit to the control end of the second switching tube Q2, and the second switching tube Q2 can make the on-off state corresponding to the control signal transmitted by the control unit and reflect the on-off state of the second switching tube Q2 to the first switching tube Q1 so as to realize on-off control of the first switching tube Q1; the resistor R5 is connected with the power supply end and the control unit, and the resistor R6 is connected with the load end and the control end so as to transmit signals of the power supply end and the load end to the control unit.
The control unit is configured to implement control of the high-side switch circuit, control of the self-diagnostic circuit, and reception and processing of signals, that is, when receiving a signal for turning on the high-side switch circuit, perform corresponding control on the self-diagnostic circuit, receive data of a power source terminal and a load terminal in a diagnostic process in the self-diagnostic process, analyze the received data, obtain a load type of the load terminal, and perform a corresponding control process for turning on the high-side switch, as shown in fig. 2, a specific process of the control method for the high-side switch circuit with the self-diagnostic function is as follows:
1) And when receiving the opening instruction of the high-side switch circuit, controlling the self-diagnosis circuit to start self-diagnosis.
In this embodiment, the self-diagnostic circuit controls the second switching tube Q2 to be turned on and off by outputting a high level or a low level through the control unit, when the second switching tube Q2 is turned on, the electrical node of the resistor R2 near the second switching tube Q2 is pulled down, so that a voltage difference is formed at two ends of the resistor R1, and the voltage difference can turn on the first switching tube Q1; when the second switch tube Q2 is turned off, the voltage of the electrical node of the resistor R2 near the second switch tube Q2 is pulled high by the power source terminal (i.e. V _ BAT in fig. 1), so that the voltage difference between the two ends of the resistor R1 disappears, and the first switch tube Q1 is turned off.
The control of the self-diagnosis process in this embodiment is: firstly, controlling the on duration time T1 (for example, 50 ms) of a first switch tube Q1 of the self-diagnosis circuit, and then, a power supply can provide a small current for a back-end load through the first switch tube Q1 and a resistor R4; then the first switch tube Q1 is closedDuration T2 (e.g., 50ms, i.e., T1= T2 in the present embodiment), i.e., control to complete the self-diagnosis process of which total diagnosis time T is diag ＝T1+T2。
2) And in the self-diagnosis process, data of the power end and the load end are collected.
In the diagnosis process, the acquisition circuit where the resistor R5 is located acquires voltage data of the power end at a set sampling rate, and the acquisition circuit where the resistor R10 is located acquires voltage data of the load end at a set sampling rate, in this embodiment, voltage sampling is performed on the power end and the load end at a rate of 1 ms/time, and corresponding voltage data is recorded.
3) And judging the load type according to the data of the power supply end and the load end.
Calculating the average value V of the voltage of the power supply terminal in the T1 period through the voltage sampling data acquired in the self-diagnosis process ad1 Average value V of terminal voltage of load in T1 period ad2 Average value V of terminal voltage of load in T2 period ad3 And the average value V of the voltage at the power supply terminal in the T2 period ad4 And based on a previously obtained high-side switch output low voltage threshold value (V) min Based on experimental data acquisition, this example employs V min = 4.8V) and the voltage difference threshold (V) across the high-side switch diff Based on experimental data acquisition, V is used in this example diff = 2.5V), and the calculated V ad1 、V ad2 、V ad3 And V ad4 Comparing, and determining the load type of the load end after comparison, where the load type of the load end in this embodiment includes an inductive load, a capacitive load, and a resistive load, and whether the load end fails can also be obtained through the comparison, and if the load end fails, a specific fault type can also be obtained, where the fault type of the load end in this embodiment includes a short circuit and a broken circuit, and the specific data comparison and the load type of the load end and the fault type determination method are as follows:
(1) if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＜V diff The external load is determined to be open.
When the load is in an open circuit, the voltage of the load end is quickly the same as that of the power supply end after the first switching tube Q1 is opened, and the voltage of the load end is 0 immediately after the first switching tube Q1 is closed, so V is in a T1 period ad1 -V ad2 ＜V diff And V is ad2 ＞V min In the T2 period V ad3 ＜V min And V is ad4 -V ad3 ＜V diff When the external load is in a fault state, the fault type is open circuit.
(2) If V ad1 -V ad2 ＞V diff 、V ad2 ＜V min And V is ad3 ＜V min It is determined that the external load is short-circuited.
When the load is in short circuit, after the first switch tube Q1 is opened, the voltage of the load end is continuously pulled down by the grounding point and is at low potential because the external load is in short circuit to the ground, and after the first switch tube Q1 is closed, the voltage of the load end is still at low potential, so that V is in a T1 period ad1 -V ad2 ＞V diff And V is ad2 ＜V min In the T2 period V ad3 ＜V min When the external load is in a fault state, the fault type is short circuit.
(3) If V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＞V min The external load is determined to be a capacitive load.
When the external load is a capacitive load, after the first switching tube Q1 is turned on, the capacitive load is in a charging state, that is, after the first switching tube Q1 is turned on, the voltage at the load end is increased from 0, but the charging current is limited by the resistor R4, so that the average value of the voltage at the load end is continuously smaller than the average value of the voltage at the power end, and after the first switching tube Q1 is turned off, the capacitive load is in a discharging state, so that the voltage value can still be detected at the load end after the first switching tube Q1 is turned off, and therefore, the voltage value V in the period T1 is detected at the load end ad1 -V ad2 ＞V diff And V is ad2 ＞V min In the T2 period V ad3 ＞V min While, an external loadIs a capacitive load.
(4) If V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＞V diff The external load is determined to be an inductive load.
When the external load is an inductive load, the inductive load can establish a magnetic field after the first switching tube Q1 is turned on, so that V exists ad1 -V ad2 ＜V diff And V is ad2 ＞V min After the first switch tube Q1 is turned off, an induced voltage is generated across the inductor based on the self-stored energy of the inductive load, the direction of the induced voltage is opposite to that of the external voltage, and since the load and the control unit are grounded, V ad3 Will acquire a negative voltage in the time, thereby making V ad4 ＞V ad3 Thus if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＞V diff When the external load is an inductive load.
(5) If V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＜V min The external load is determined to be a resistive load.
When the external load is a resistive load, after the first switching tube Q1 is turned on, the resistive load and the resistor R4 form a voltage division, resulting in V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And the voltage at the load end is 0 immediately after the first switch tube Q1 is closed, so V is in the T1 period ad1 -V ad2 ＞V diff And V is ad2 ＞V min In the T2 period, V ad3 ＜V min The external load is a resistive load.
4) And performing corresponding starting control on the high-side switching circuit according to the load type.
(1) When the external load is in an open circuit, the control unit rejects an external command for opening the high-side switch circuit and feeds back fault information to the command sending unit. When the external load is in an open circuit, namely the external load has a fault, the instruction for opening the high-side switching circuit is not executed, and the fault information of the external load is sent to the command issuing unit, so that the damage to the high-side switching circuit or the load caused by opening the high-side switching circuit when the external load has a fault is avoided, and the reliable process for controlling the high-side switching circuit is further ensured.
(2) When the external load is short-circuited, the control unit rejects a command of externally opening the high-side switch circuit and feeds back fault information to the command sending unit. When external load short-circuits, namely, external load has faults, therefore, the instruction of opening the high-side switch circuit is not executed, and external load fault information is sent to the command issuing unit, and further, when external load faults are avoided, the high-side switch circuit is opened, damage is caused to the high-side switch circuit or the load, and further, the reliable process of controlling the high-side switch circuit is ensured.
(3) When the external load is a capacitive load, the control unit performs a pre-charge process on the load, that is, turns on the first switch Q1 for a time period T3 (for example, 100ms, which is set to reduce the capacity of the capacitive load and avoid the failure of turning on the high-side switch circuit due to the impact current of the capacitive load after turning on the high-side switch circuit), turns on the high-side switch circuit, and turns off the first switch Q1 after 5 ms. When the external load is a capacitive load, the capacitive load is pre-charged firstly to reduce the capacity of the capacitive load, so that the high-side switching circuit is turned on after the capacity of the capacitive load is not enough to generate an impact current, and further, the problem that the high-side switching circuit is mistakenly protected due to the impact current of the capacitive load at the moment of turning on the high-side switching circuit is avoided.
(4) When the external load is an inductive load, the control unit performs a pre-charging process on the load, that is, turns on the first switch tube Q1 for T4 (for example, 50ms, which is set to reduce the capacity of the inductive load and avoid the failure of turning on the high-side switch circuit due to the impact current of the inductive load after turning on the high-side switch circuit), turns on the high-side switch circuit again, and turns off the first switch tube Q1 after 5 ms. As the external load is a capacitive load, since both the inductive load and the capacitive load have an inrush current at the moment when the high-side switch circuit is turned on, a pre-charging process is also required when the external load is an inductive load, so as to reduce the capacity of the inductive load and avoid the influence of the inrush current at the moment when the high-side switch is turned on. And the pre-charging is closed after the high-side switch circuit is turned on for a set time (for example, the set time is 5 ms) so as to avoid the situation that the impact current still exists when the high-side switch circuit is turned on after the pre-charging is directly turned off.
(5) When the external load is a resistive load, the control unit directly starts the high-side switch circuit. When the external load is a resistive load, no inrush current exists after the high-side switch circuit is turned on, so that the high-side switch circuit can be directly turned on.
By the control method, the type of the external load or the type of the external fault can be accurately judged, the command for starting the high-side switch circuit is refused to be executed when the external load has the fault, and the fault signal of the external load is transmitted to the command lower transmitting end, so that irreversible damage to the high-side switch circuit after the high-side switch is opened when the external load has the fault is avoided; when the external load is an inductive load or a capacitive load, the external load is subjected to pre-charging processing to reduce the capacity of the external load, so that when the high-side switch circuit is turned on, the influence of impulse current is avoided, and the smooth turning on of the high-side switch is facilitated.
The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention, the scope of the present invention is defined by the appended claims, and all structural changes that can be made by using the contents of the description and the drawings of the present invention are intended to be embraced therein.
Claims (8)
1. A high-side switch circuit with a self-diagnosis function comprises a high-side switch and a control unit, wherein the high-side switch is arranged between a power supply and a load, and the control unit is connected with the high-side switch in a control mode so as to control the on-off of the high-side switch; the acquisition circuit comprises a power end voltage detection port and a load end voltage detection port, the power end voltage detection port is connected to the control unit through the power end acquisition circuit, and the load end voltage detection port is connected to the control unit through the load end acquisition circuit;
the control unit is used for sending a diagnosis starting instruction to the driving switch when receiving the instruction of starting the high-side switch, performing diagnosis control on the driving switch, realizing the conduction or the blockage of the power supply of a circuit where the driving switch is located to a load, acquiring a power supply end voltage signal and a load end voltage signal after diagnosis starting, judging the load type according to the power supply end voltage signal and the load end voltage signal, and performing pre-charging treatment when the load type is an inductive load type or a capacitive load type so as to reduce current impact when the high-side switch circuit is started.
2. The high-side switching circuit with self-diagnostic function according to claim 1, wherein when the load type is an inductive load type or a capacitive load type, the pre-charging process is: the control unit controls the conduction of the driving circuit of the self-diagnosis circuit for set time.
3. The high-side switch circuit with self-diagnostic function according to claim 1, characterized in that the diagnostic control is: controlling the drive switch to be turned on for setting a first time, and then controlling the drive switch to be turned off for setting a second time; the power supply terminal voltage signal includes: mean value V of voltage signal at power supply end in first time period ad1 And the mean value V of the power supply terminal voltage signal in the second period ad4 (ii) a The load terminal voltage signal comprises a mean value V of the load terminal voltage signal in a first time period ad2 And the mean value V of the voltage signal at the load end in the second time period ad3 。
4. The high-side switching circuit with self-diagnostic function according to claim 3, wherein the judgment of the load type based on the power source terminal voltage signal and the load terminal voltage signal is based on:
if V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＞V min Judging the load to be capacitive load;
if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＞V diff Judging the load to be inductive load;
wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is the threshold value of the voltage difference between the two ends of the high-side switch.
5. The high-side switching circuit with self-diagnostic function according to claim 1, wherein the load types further include an open load type and a short load type; when the load type is an open circuit load type or a short circuit load type, the control unit refuses to execute the command of opening the high-side switch and sends alarm information to the sending unit of the command of opening the high-side switch.
6. The high-side switching circuit with self-diagnostic function according to claim 5, characterized in that the types of the open load and the short load are judged based on:
if V ad1 -V ad2 ＜V diff 、V ad2 ＞V min And V is ad3 ＜V min 、V ad4 -V ad3 ＜V diff Judging that the load is open;
if V ad1 -V ad2 ＞V diff 、V ad2 ＜V min And V is ad3 ＜V min Judging that the load is short-circuited;
wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is a threshold value of voltage difference between two ends of the high-side switch, V ad1 To average value of voltage signal of power supply terminal in time period of on-drive switch ad2 To average value of voltage signal at load terminal in time period of conducting drive switch, V ad3 For blocking the mean value of the voltage signal across the load terminal during the period of driving the switch, V ad4 The average value of the power supply terminal voltage signal in the time period of blocking the driving switch.
7. The high-side switch circuit with self-diagnostic function according to claim 1, characterized in that the load types further include a resistive load type; when the load type is a resistive load, the control unit executes a command of opening the high-side switch; the judgment basis of the resistive load type is as follows:
if V ad1 -V ad2 ＞V diff 、V ad2 ＞V min And V is ad3 ＜V min Judging the load to be a resistive load; wherein, V min Is a low voltage threshold value, V, at the output of the high-side switch diff Is a threshold value of voltage difference between two ends of the high-side switch, V ad1 To average value of voltage signal of power supply terminal in time period of on-drive switch ad2 To mean value of voltage signal at load terminal in time period of conducting drive switch, V ad3 For blocking the mean value V of the voltage signal at the load end in the switching time period ad3 。
8. The high-side switching circuit with self-diagnostic function according to claim 1, wherein the driving switch comprises two triodes, namely a first switching tube and a second switching tube, wherein the emitter and the collector of the first switching tube are respectively used for connecting a power supply end and a load end, and the base of the first switching tube is connected with the collector of the second switching tube; the emitting electrode of the second switch tube is used for grounding, and the base electrode of the second switch tube is connected with the control unit.
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| CN202211168166.5A CN115395935A (en) | 2022-09-23 | 2022-09-23 | High-side switch circuit with self-diagnosis function |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116382385A (en) * | 2023-04-03 | 2023-07-04 | 无锡市稳先微电子有限公司 | Temperature control method, temperature control circuit, intelligent electronic switch and automobile |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116382385A (en) * | 2023-04-03 | 2023-07-04 | 无锡市稳先微电子有限公司 | Temperature control method, temperature control circuit, intelligent electronic switch and automobile |
| CN116382385B (en) * | 2023-04-03 | 2024-03-05 | 无锡市稳先微电子有限公司 | Temperature control method, temperature control circuit, intelligent electronic switch and automobile |
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