CN211720467U - Protection circuit of power MOS tube in switching power supply - Google Patents
Protection circuit of power MOS tube in switching power supply Download PDFInfo
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- CN211720467U CN211720467U CN202020394117.3U CN202020394117U CN211720467U CN 211720467 U CN211720467 U CN 211720467U CN 202020394117 U CN202020394117 U CN 202020394117U CN 211720467 U CN211720467 U CN 211720467U
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Abstract
The utility model discloses a protection circuit of a power MOS tube in a switch power supply, which belongs to the technical field of switch power supplies and solves the problems of small volume and no self-protection function of the existing MOS tube; the device comprises a control drive circuit, a detection and analysis circuit, an absorption and discharge circuit, a main power circuit and a measurement circuit, and is characterized in that the control drive circuit is electrically connected with the detection and analysis circuit and is also electrically connected with the absorption and discharge circuit; the measuring circuit includes resistance R1, current detection table A1, current detection table A2, voltage detection table V1 and voltage detection table V2, and current detection table A1, current detection table A2, voltage detection table V1 and voltage detection table V2 link to each other with detection analysis circuit respectively, the utility model discloses a drive current and the accurate measurement of voltage to the MOS pipe are favorable to controlling opening and shutting down of MOS pipe, have improved the control performance of MOS pipe.
Description
Technical Field
The utility model relates to a switching power supply technical field specifically is a protection circuit of power MOS pipe among switching power supply.
Background
The MOSFET is a metal oxide semiconductor field effect transistor, and with the development of electronic power technology, the power MOSFET has good high-frequency performance, small switching loss, high input impedance, small driving power, simple driving circuit and the like, the MOS tube is used as a switch in a switching power supply circuit more and more widely, but because the MOS tube has small volume and does not have the protection function, when the phenomena of feedback charging or spike pulse exist, the main circuit generates large current and large voltage, if the protection is not timely, or the voltage and the current are not discharged to cause that the bus voltage exceeds the bearing voltage and the current of the MOS tube, the MOS tube can be burnt, therefore, the cost of research and development is greatly improved, meanwhile, the MOS tube is a voltage control type transistor, but has a Miller platform, therefore, the control of the MOS transistor is directly affected by the magnitude of the driving signal current and voltage, which is not favorable for the continuity of the circuit and the safety performance of the circuit.
However, because the MOS tube has a small volume and does not have a protection function, when phenomena such as feedback charging or spike pulse exist, the main circuit generates large current and large voltage, and if the protection is not in time or the voltage and the current are not released into a loop, the bus voltage exceeds the bearing voltage and the current of the MOS tube, and the MOS tube can be burnt; therefore, we propose a protection circuit for power MOS transistor in switching power supply.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a protection circuit of power MOS pipe among switching power supply to solve the problem of small, do not have self-protect function of current MOS pipe.
In order to achieve the above object, the utility model provides a following technical scheme:
a protection circuit of a power MOS tube in a switching power supply comprises a control drive circuit, a detection and analysis circuit, an absorption bleeder circuit, a main power circuit and a measurement circuit, and is characterized in that the control drive circuit is electrically connected with the detection and analysis circuit and the control drive circuit is also electrically connected with the absorption bleeder circuit; the measuring circuit comprises a resistor R1, a current detection table A1, a current detection table A2, a voltage detection table V1 and a voltage detection table V2, wherein the current detection table A1, the current detection table A2, the voltage detection table V1 and the voltage detection table V2 are respectively connected with the detection analysis circuit.
As a further aspect of the present invention: the main power circuit comprises a primary inductor L1 of the transformer and a power switch tube Q1, and the absorption bleeder circuit comprises a resistor R2, a resistor R3, a capacitor C1 and a power MOS tube Q2.
As a further aspect of the present invention: the current detection table A1 and the voltage detection table V1 are used for measuring the driving current and the driving voltage of the gate of the MOS transistor, and the current detection table A2 and the voltage detection table V2 are used for measuring the current and the voltage of the circuit bus.
As a further aspect of the present invention: the resistor R1 is a sliding driving resistor, the detection and analysis circuit is used for measuring the value of A1 measured by the circuit, detecting the driving current flowing through the MOS and making corresponding analysis, and then sending the analyzed data result to the control and driving circuit, and the main power circuit is used for carrying out chopping control on the bus voltage in the switching power supply.
Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses a to the accurate measurement of the drive current of MOS pipe and voltage, be favorable to controlling opening and turn-off of MOS pipe, improved the control performance of MOS pipe, reduce the heat dissipation of power, increased switching power supply's efficiency, realized the accurate measurement to switching power supply bus current and voltage, be favorable to the spike pulse on the control bus, reduced the probability that MOS pipe punctures, improved switching power supply's reliability.
Drawings
Fig. 1 is a schematic structural diagram of a protection circuit of a power MOS transistor in a switching power supply.
Fig. 2 is a schematic diagram of a control principle of a protection circuit of a power MOS transistor in a switching power supply.
Detailed Description
The technical solutions of the present invention will be described in further detail with reference to the following detailed description, and it should be understood that the described embodiments are only some embodiments, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example 1
Referring to fig. 1-2, in an embodiment of the present invention, a protection circuit for a power MOS transistor in a switching power supply includes a control driving circuit, a detection and analysis circuit, an absorption and discharge circuit, a main power circuit, and a measurement circuit; the control drive circuit is electrically connected with the detection and analysis circuit and is also electrically connected with the absorption and discharge circuit;
the measuring circuit comprises a resistor R1, a current detection table A1, a current detection table A2, a voltage detection table V1 and a voltage detection table V2, the current detection table A1, the current detection table A2, the voltage detection table V1 and the voltage detection table V2 are respectively connected with the detection analysis circuit, the main power circuit comprises a primary side inductor L1 and a power switch tube Q1 of the transformer, and the absorption bleeder circuit comprises a resistor R2, a resistor R3, a capacitor C1 and a power MOS tube Q2;
the current detection table A1 and the voltage detection table V1 are used for measuring the driving current and the driving voltage of the gate pole of the MOS tube, and the voltage and the current are controlled when the MOS tube is switched on and off, and the Miller platform needs to be charged at the same time, so that the voltage and the current of the Miller platform are detected, the switching on and off of the MOS tube can be better controlled, the performance of the MOS tube can be better exerted, and the heat dissipation of the whole power supply and the efficiency of the power supply can be better controlled;
the current detection table A2 and the voltage detection table V2 are used for measuring the current and the voltage of a circuit bus, because the voltage and the current of the bus can change along with the existence of an inductive load in the process of switching on and switching off the MOS transistor, the service life of the MOS transistor can be influenced by the overhigh voltage and current, and the current detection table A2 and the voltage detection table V2 are beneficial to protecting a diode;
the resistor R1 is a sliding drive resistor, and the resistor R1 can adjust the magnitude of the drive current by adjusting the resistance value;
one end of the resistor R1 is connected with one end of a current detection meter A1, the other end of the current detection meter A1 is connected with a gate pole of an MOS tube Q1, the other end of a voltage detection meter V1 is connected with a gate pole of an MOS tube Q1 of the main power circuit, one end of a current detection meter A2 is connected with VCC, the other end of the current detection meter A2 is connected with a voltage detection meter V2, and the current detection meter A2 is connected with one end of a primary inductor L1, one end of a resistor R2 and one end of a resistor R3.
The other end of the voltage detection table V2 is connected with the source electrode of the MOS tube Q1 of the main power circuit, and meanwhile, the voltage detection table V2 is also connected with one end of the capacitor C1 and the source electrode of the power MOS tube Q2; the other end of the primary side inductor L1 is connected with the drain electrode of the MOS tube; the other end of the resistor R2 is connected with one end of the capacitor C1, and one end of the resistor R3 is connected with the drain electrode of the power MOS transistor Q2;
the detection and analysis circuit is used for measuring the value of A1 measured by the circuit, detecting the driving current flowing through the MOS and carrying out corresponding analysis, then sending the analyzed data result to the control driving circuit, and controlling the turn-on and turn-off speeds of the MOS driving circuit by main control so as to realize accurate control of the turn-on and turn-off of the MOS and be beneficial to the improvement of the heat dissipation and the performance of the MOS; the driving voltage flowing through the MOS is detected through the value of V1 measured by the measuring circuit, corresponding analysis is made, and then the analyzed data result is sent to the control driving circuit, and the gate pole of the MOS is protected from being broken down by high voltage through the main control; the values of A2 and V2 measured by the measuring circuit detect the current and voltage on the bus, and control data are transmitted to the control driving circuit;
by detecting and analyzing four data of A1, A2, V1 and V2, the analysis output is transmitted to the control drive circuit, so that the control drive controls the MOS, and the reliability of MOS short-circuit protection is not influenced when the short-circuit protection fails or an overcurrent non-short-circuit state exists, namely the reliability of the short-circuit protection is improved.
Example 2
Referring to fig. 1-2, in an embodiment of the present invention, a protection circuit for a power MOS transistor in a switching power supply includes a control driving circuit, a detection and analysis circuit, an absorption and discharge circuit, a main power circuit, and a measurement circuit; the control drive circuit is electrically connected with the detection and analysis circuit and is also electrically connected with the absorption and discharge circuit;
the measuring circuit comprises a resistor R1, a current detection table A1, a current detection table A2, a voltage detection table V1 and a voltage detection table V2, the current detection table A1, the current detection table A2, the voltage detection table V1 and the voltage detection table V2 are respectively connected with the detection analysis circuit, the main power circuit comprises a primary side inductor L1 and a power switch tube Q1 of the transformer, and the absorption bleeder circuit comprises a resistor R2, a resistor R3, a capacitor C1 and a power MOS tube Q2;
the current detection table A1 and the voltage detection table V1 are used for measuring the driving current and the driving voltage of the gate pole of the MOS tube, and the voltage and the current are controlled when the MOS tube is switched on and off, and the Miller platform needs to be charged at the same time, so that the voltage and the current of the Miller platform are detected, the switching on and off of the MOS tube can be better controlled, the performance of the MOS tube can be better exerted, and the heat dissipation of the whole power supply and the efficiency of the power supply can be better controlled;
the current detection table A2 and the voltage detection table V2 are used for measuring the current and the voltage of a circuit bus, because the voltage and the current of the bus can change along with the existence of an inductive load in the process of switching on and switching off the MOS transistor, the service life of the MOS transistor can be influenced by the overhigh voltage and current, and the current detection table A2 and the voltage detection table V2 are beneficial to protecting a diode;
the resistor R1 is a sliding drive resistor, and the resistor R1 can adjust the magnitude of the drive current by adjusting the resistance value;
one end of the resistor R1 is connected with one end of a current detection meter A1, the other end of the current detection meter A1 is connected with a gate pole of an MOS tube Q1, the other end of a voltage detection meter V1 is connected with a gate pole of an MOS tube Q1 of the main power circuit, one end of a current detection meter A2 is connected with VCC, the other end of the current detection meter A2 is connected with a voltage detection meter V2, and the current detection meter A2 is connected with one end of a primary inductor L1, one end of a resistor R2 and one end of a resistor R3.
The other end of the voltage detection table V2 is connected with the source electrode of the MOS tube Q1 of the main power circuit, and meanwhile, the voltage detection table V2 is also connected with one end of the capacitor C1 and the source electrode of the power MOS tube Q2; the other end of the primary side inductor L1 is connected with the drain electrode of the MOS tube; the other end of the resistor R2 is connected with one end of the capacitor C1, and one end of the resistor R3 is connected with the drain electrode of the power MOS transistor Q2;
the detection and analysis circuit is used for measuring the value of A1 measured by the circuit, detecting the driving current flowing through the MOS and carrying out corresponding analysis, then sending the analyzed data result to the control driving circuit, and controlling the turn-on and turn-off speeds of the MOS driving circuit by main control so as to realize accurate control of the turn-on and turn-off of the MOS and be beneficial to the improvement of the heat dissipation and the performance of the MOS; the driving voltage flowing through the MOS is detected through the value of V1 measured by the measuring circuit, corresponding analysis is made, and then the analyzed data result is sent to the control driving circuit, and the gate pole of the MOS is protected from being broken down by high voltage through the main control; the values of A2 and V2 measured by the measuring circuit detect the current and voltage on the bus, and control data are transmitted to the control driving circuit;
by detecting and analyzing four data of A1, A2, V1 and V2, the analysis output is transmitted to the control drive circuit, so that the control drive controls the MOS, and the reliability of MOS short-circuit protection is not influenced when the short-circuit protection fails or an overcurrent non-short-circuit state exists, namely the reliability of the short-circuit protection is improved.
The control driving circuit is used for analyzing and comparing the data provided by the detection analysis circuit, comparing the detection and analysis data of the four data A1, A2, V1 and V2 with theoretical values in a program, outputting PWM waveforms, controlling the power switch tube Q1 and the power MOS tube Q2, adjusting the resistance value of the sliding resistor R1 when the data of A1 and V1 are larger than or smaller than the theoretical values, and adjusting the driving voltage at the same time to ensure the stability of the driving current and the voltage; when the MOS switching-on and switching-off speed needs to be increased, the driving circuit is controlled to reduce the resistance value of the sliding rheostat, the driving capability is increased, the power switch tube Q1 is charged into the Miller platform, and when the data of A2 and V2 are larger than the theoretical value, in order to prevent the power switch tube Q1 from being broken down by overhigh voltage, the driving circuit is controlled to output PWM according to a programmed program, so that the power MOS tube Q2 is conducted, and the energy on a bus is discharged.
The main power circuit is used for carrying out chopping control on bus voltage in the switching power supply, so that the voltage output by the secondary side meets the requirement of a load, meanwhile, the primary side inductor stores energy, and when the power control power switching tube Q1 is turned off, a stable power supply is continuously provided for the load.
The utility model has the advantages that: the utility model discloses a to the accurate measurement of the drive current of MOS pipe and voltage, be favorable to controlling opening and turn-off of MOS pipe, improved the control performance of MOS pipe, reduce the heat dissipation of power, increased switching power supply's efficiency, realized the accurate measurement to switching power supply bus current and voltage, be favorable to the spike pulse on the control bus, reduced the probability that MOS pipe punctures, improved switching power supply's reliability.
It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (3)
1. A protection circuit of a power MOS tube in a switching power supply comprises a control drive circuit, a detection and analysis circuit, an absorption bleeder circuit, a main power circuit and a measurement circuit, and is characterized in that the control drive circuit is electrically connected with the detection and analysis circuit and the control drive circuit is also electrically connected with the absorption bleeder circuit; the measuring circuit comprises a resistor R1, a current detection table A1, a current detection table A2, a voltage detection table V1 and a voltage detection table V2, the current detection table A1, the current detection table A2, the voltage detection table V1 and the voltage detection table V2 are respectively connected with the detection and analysis circuit, the main power circuit comprises a primary inductor L1 and a power switch tube Q1 of a transformer, the absorption and discharge circuit comprises a resistor R2, a resistor R3, a capacitor C1 and a power MOS tube Q2, the other end of the voltage detection table V1 is connected with the MOS tube Q1, one end of the current detection table A1 is connected with VCC, the other end of the current detection table A1 is connected with the voltage detection table V1, and is simultaneously connected with one end of the primary inductor L1, one end of the resistor R1 and one end of the resistor R1, the other end of the voltage detection table V1 is connected with a gate of the MOS tube Q1 of the main power circuit, and the other end of the voltage detection table V1 is also connected with one end of; the other end of the primary side inductor L1 is connected with the drain electrode of the MOS tube; the other end of the resistor R2 is connected with one end of the capacitor C1, and one end of the resistor R3 is connected with the drain of the power MOS transistor Q2.
2. The protection circuit of power MOS transistor in switching power supply of claim 1, wherein the current detecting table A1 and the voltage detecting table V1 are used to measure the driving current and the driving voltage of the gate of MOS transistor, one end of the resistor R1 is connected to one end of the current detecting table A1, and the other end of the current detecting table A1 is connected to the gate of MOS transistor Q1.
3. The protection circuit of power MOS transistor in switching power supply as claimed in claim 1, wherein the resistor R1 is a sliding driving resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020394117.3U CN211720467U (en) | 2020-03-25 | 2020-03-25 | Protection circuit of power MOS tube in switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020394117.3U CN211720467U (en) | 2020-03-25 | 2020-03-25 | Protection circuit of power MOS tube in switching power supply |
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| Publication Number | Publication Date |
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| CN211720467U true CN211720467U (en) | 2020-10-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020394117.3U Active CN211720467U (en) | 2020-03-25 | 2020-03-25 | Protection circuit of power MOS tube in switching power supply |
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| CN (1) | CN211720467U (en) |
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- 2020-03-25 CN CN202020394117.3U patent/CN211720467U/en active Active
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