CN210724196U - Output protection circuit of power supply - Google Patents
Output protection circuit of power supply Download PDFInfo
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- CN210724196U CN210724196U CN201921832761.8U CN201921832761U CN210724196U CN 210724196 U CN210724196 U CN 210724196U CN 201921832761 U CN201921832761 U CN 201921832761U CN 210724196 U CN210724196 U CN 210724196U
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Abstract
The utility model discloses an output protection circuit of a power supply, which comprises a control module, a voltage stabilizing module, an output overvoltage protection module, an output overcurrent protection module and an inversion module; the control module is respectively connected with the voltage stabilizing module, the output overvoltage protection module, the output overcurrent protection module and the inversion module; control module input COM, UVLO, CS, VREF respectively with voltage stabilizing module's output COM, output overvoltage protection module output UVLO, output overcurrent protection module's output CS and VREF link to each other, control module's output links to each other with the input of contravariant module, the utility model discloses when power output takes place to overflow or the excessive pressure, can detect overflow or excessive pressure signal rapidly to close the PWM ripples through control module, make contravariant module stop work, thereby improve the reliability of power, in addition, when power output voltage, the non-excessive pressure of electric current, overflow, power module can be from starting, simple structure, the reliability is high.
Description
Technical Field
The utility model relates to a power technical field especially relates to an output protection circuit of power.
Background
The existing output protection functions include overvoltage, overcurrent and the like, but output current is generally isolated and sampled by a direct current transformer, but the cost is higher, or resistance sampling is carried out, and then the output current is supplied by a comparison amplifying circuit and the like, and an external power supply is additionally needed, so that the circuit is complex and the cost is increased.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model provides a low cost, the circuit is simple, the reliable output protection circuit of job stabilization to the output protection circuit of the power that the production test was used.
The purpose of the utility model can be realized by the following technical scheme:
an output protection circuit of a power supply comprises a control module, a voltage stabilizing module, an output overvoltage protection module, an output overcurrent protection module and an inversion module;
the control module is respectively connected with the voltage stabilizing module, the output overvoltage protection module, the output overcurrent protection module and the inversion module;
the input ends COM, UVLO, CS and VREF of the control module are respectively connected with the output end COM of the voltage stabilizing module, the output end UVLO of the output overvoltage protection module and the output ends CS and VREF of the output overcurrent protection module, and the output end of the control module is connected with the input of the inverter module.
Furthermore, the control module is an analog power management chip or a DSP chip.
Furthermore, the voltage stabilizing module consists of a voltage sampling circuit, a voltage stabilizing circuit and a first isolating circuit;
the output end Vs of the voltage sampling circuit is connected with the input end of the voltage stabilizing circuit, and the output end of the voltage stabilizing circuit is connected with the input end of the first isolating circuit;
the first isolation circuit is connected with the input end of the control module;
the voltage sampling circuit comprises a resistor R1 and a resistor R2, the input end of the voltage sampling circuit is a power output positive end Vo +, a power output negative end Vo-, the power output positive end Vo + is connected with a pin 1 of the resistor R1, the power output negative end Vo-is connected with a pin 2 of the resistor R2, and the output end Vs of the voltage sampling circuit is respectively connected with a pin 2 of the resistor R1 and a pin 1 of the resistor R2;
the voltage stabilizing circuit comprises a resistor R5, a resistor R6, a capacitor C1, a capacitor C2, a voltage stabilizing source Q1 and an isolation optocoupler U1, wherein the input end of the voltage stabilizing circuit is respectively connected with a sampling voltage Vs of the output end of the voltage sampling circuit, a positive power output terminal Vo +, and a negative power output terminal Vo-, the input end Vs of the voltage stabilizing circuit is respectively connected with a reference voltage REF of a voltage stabilizing source Q1, a 2 pin of the capacitor C1, and a 2 pin of the capacitor C2, the cathode of the voltage stabilizing source Q1 is respectively connected with a 1 pin of the capacitor C2, a 1 pin of the resistor R6 and the cathode of the isolation optocoupler U1, the anode of the voltage stabilizing source Q1 is respectively connected with the negative power output terminal Vo-, the capacitor C1 is connected with the 2 pin of the resistor, the 1 pin of the resistor R5 is connected with the anode of the U1, and the 2 pin of the resistor R5 is connected;
the isolation optocoupler U1 is a linear optocoupler K10104D, and the voltage regulator source Q1 is TL 431.
Furthermore, the output overvoltage protection module comprises an auxiliary power supply circuit, a voltage division circuit, a second comparison circuit and a third isolation circuit;
the input end of the second comparison circuit is connected with the output end of the voltage division circuit and the output end Vs of the voltage sampling circuit in the voltage stabilization module, the positive electrode of the power supply end of the second comparison circuit is connected with the output end Vc of the auxiliary power supply circuit, the negative electrode of the power supply end of the second comparison circuit is connected with the negative output end Vo-of the power supply, the output end of the second comparison circuit is connected with the positive electrode of the input end of the third isolation circuit, the positive input end of the auxiliary power supply circuit is connected with the positive output end of the power supply, the negative input end of the auxiliary power supply circuit is connected with the negative output end of the power supply, the input end of the voltage division circuit is respectively connected with the positive output end and the negative output end of the power supply, and the output end of the third isolation;
the second comparison circuit comprises a comparator N3, a resistor R9, a resistor R24 and a resistor R10, wherein a power supply pin 8 of the comparator N3 is respectively connected with a pin 1 of the resistor R9, a pin 1 of the resistor R24 and power supply Vc, a power supply negative terminal pin 4 of the comparator N3 is connected with an output power Vo-, an anode of a voltage stabilizing diode D3, an input pin 5 of the comparator N3 is connected with an output end of a voltage dividing circuit, and an input pin 6 of the comparator N3 is respectively connected with a cathode of the voltage stabilizing diode D3 and a pin 2 of the resistor R24;
the voltage division circuit comprises a resistor R7, a resistor R8 and a capacitor C4, the input positive end of the voltage division circuit is respectively connected with a pin 1 of the resistor R7 and the positive end Vo + of the power output, the input negative end of the voltage division circuit is respectively connected with a pin 2 of the resistor R8 and a pin 2 of the capacitor C4, and the output end of the voltage division circuit is respectively connected with a pin 2 of the resistor R7, a pin 1 of the resistor R8 and a pin 1 of the capacitor C4;
the auxiliary power supply circuit comprises a resistor R4 and a voltage stabilizing diode D1, the input positive end of the auxiliary power supply circuit is respectively connected with the positive end Vo + of the output power supply and the pin 1 of the resistor R4, the input negative end of the auxiliary power supply circuit is respectively connected with the negative end Vo-of the output power supply and the anode of the voltage stabilizing diode D1, and the output end Vc of the auxiliary power supply circuit is respectively connected with the pin 2 of the resistor R4 and the cathode of the voltage stabilizing diode D1.
Furthermore, the output overcurrent protection module consists of a current sampling resistor, a reverse following and amplifying circuit, a first comparison circuit and a second isolation circuit;
the current sampling resistor is connected in series between the negative end Vo-of the power output and the negative electrode of the rectification filter of the output power supply, the input end of the current sampling resistor is connected with the negative end Vo-of the power output, the output end of the sampling circuit is connected with the negative electrode of the rectification filter of the output power supply and the input end of the reverse follower circuit respectively, the positive and negative ends of the input power supply of the reverse follower circuit are connected with the output end Vc of the auxiliary power supply circuit and the negative end Vo-of the power output in the output overvoltage protection module respectively, the output end of the reverse follower circuit is connected with the input end of the amplifying circuit, the output end of the amplifying circuit is connected with the input end of the first comparing circuit, the output end of the first comparing circuit is connected with the input end of the second isolating circuit, and the output end of the second isolating circuit;
the reverse follower circuit comprises an operational amplifier N2A, a resistor R23, a resistor R11, a resistor R12 and a capacitor C5, an input end Vi of the reverse follower circuit is respectively connected with a pin 2 of the resistor R23 and a pin 1 of the capacitor C5, an output end of the reverse follower circuit is respectively connected with a pin 1 of the resistor R12 and an input end of the amplification circuit, a power supply positive terminal 8 of the operational amplifier N2 is connected with an output end Vc of an auxiliary power supply circuit in the output overvoltage protection module, a power supply negative terminal 4 of the operational amplifier N2 is respectively connected with a negative pole Vo-, a pin 3 of an input end of the operational amplifier N2 and a pin 2 of the capacitor C5, an input pin 2 of the operational amplifier N2 is respectively connected with a pin 1 of the resistor R23 and a pin 2 of the resistor R11, and an output pin 1 of the operational amplifier N2 is respectively connected with a pin 2 of the resistor R12 and a pin 1 of the resistor R11;
the amplifying circuit comprises an operational amplifier N2B, a resistor R13, a resistor R14 and a resistor R15, wherein a pin 5 at the input end of the operational amplifier N2B is connected with a pin 1 of a resistor R12 in the reverse follower circuit, a pin 6 of the operational amplifier N2 is respectively connected with a pin 1 of the resistor R13 and a pin 2 of the resistor R14, a pin 2 of the resistor R13 is connected with a negative end Vo-of power output, a pin 7 of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R14 and a pin 2 of the resistor R15, and the output end of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R15 and the input end of the first comparison circuit;
the first comparison circuit comprises a comparator N3, a resistor R16, a resistor R17, a resistor R18 and a resistor R19, wherein a pin 3 at the input end of the comparator N3 is connected with a pin 1 of a resistor R15 in the amplification circuit, a pin 2 at the input end of the comparator N3 is respectively connected with a pin 2 of the resistor R17 and a pin 1 of a resistor R16, a pin 1 of the resistor R17 is respectively connected with a pin Vo + of a power output positive terminal and a pin 1 of a resistor R18, a pin 2 of the resistor R16 is connected with a power output negative terminal Vo-, a pin 1 at the output end of the comparator N3 is respectively connected with a pin 2 of the resistor R18 and a pin 2 of the resistor R19, and a pin 1 of the resistor R19 is connected with the input end of the second isolation circuit;
the second isolation circuit comprises an isolation optocoupler U3, a resistor R20 and a resistor R21, an input anode of the isolation optocoupler U3 is connected with an output end of the first comparison circuit, an input cathode of the isolation optocoupler U3 is connected with an output negative end, a collector of an output end of the isolation optocoupler U3 is connected with an input end VREF of the control module, 2 pins of an output end emitter resistor R20 of the isolation optocoupler U3 are connected, 1 pin of the resistor R20, 1 pin of the resistor R21 and an input end CS of the control module are connected, and the 2 pins of the resistor R21 are connected with an output power supply negative end Vo-.
Furthermore, the inverter module is an inverter circuit combining a MOSFET or an IGBT and an isolation transformer.
The utility model has the advantages that:
the utility model discloses a power output protection circuit, when power output's voltage, electric current are for overflowing, excessive pressure, can detect rapidly and overflow or overvoltage signal to close the PWM ripples through control module, make contravariant module stop work, thereby improve the reliability of power, in addition, at power output's voltage, electric current non-excessive pressure, when overflowing, power module can self-starting, the utility model discloses simple structure, the reliability is high.
Drawings
The present invention will be further described with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of an output protection circuit of a power supply according to the present invention;
fig. 2 is a schematic diagram of an output voltage stabilizing module in an output protection circuit of the power supply of the present invention;
fig. 3 is a schematic diagram of an output overvoltage protection module in an output protection circuit of the power supply of the present invention;
fig. 4 is a schematic diagram of an output overcurrent protection module of the power supply of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
As shown in fig. 1, an output protection circuit of a power supply includes a control module, a voltage stabilizing module, an output overvoltage protection module, an output overcurrent protection module, and an inverter module;
the control module is respectively connected with the voltage stabilizing module, the output overvoltage protection module, the output overcurrent protection module and the inversion module;
the input ends COM, UVLO, CS and VREF of the control module are respectively connected with the output end COM of the voltage stabilizing module, the output end UVLO of the output overvoltage protection module and the output ends CS and VREF of the output overcurrent protection module, and the output end of the control module is connected with the input of the inverter module.
The control module is an analog power management chip or a DSP chip;
through output voltage stabilization module output feedback to control module COM end, control module carries out PWM control in inside, with the drive contravariant module, thereby stabilize power output voltage, when power output was excessive pressure, control module input UVLO is pulled down by output overvoltage protection module, thereby turn-off PWM ripples, the protection contravariant module does not receive the damage, when power output overflows, control module input CS end input certain voltage, through the comparison of control module internal voltage, and turn-off control module's PWM ripples, the protection contravariant module does not receive the damage.
As shown in fig. 2, the voltage stabilizing module is composed of a voltage sampling circuit, a voltage stabilizing circuit and a first isolating circuit;
the output end Vs of the voltage sampling circuit is connected with the input end of the voltage stabilizing circuit, and the output end of the voltage stabilizing circuit is connected with the input end of the first isolating circuit;
the first isolation circuit is connected with the input end of the control module;
the voltage sampling circuit comprises a resistor R1 and a resistor R2, the input end of the voltage sampling circuit is a power output positive end Vo +, a power output negative end Vo-, the power output positive end Vo + is connected with a pin 1 of the resistor R1, the power output negative end Vo-is connected with a pin 2 of the resistor R2, and the output end Vs of the voltage sampling circuit is respectively connected with a pin 2 of the resistor R1 and a pin 1 of the resistor R2;
the voltage stabilizing circuit comprises a resistor R5, a resistor R6, a capacitor C1, a capacitor C2, a voltage stabilizing source Q1 and an isolation optocoupler U1, wherein the input end of the voltage stabilizing circuit is respectively connected with the sampling voltage Vs of the output end of the voltage sampling circuit, the positive end Vo + of the power output and the negative end Vo-of the power output, the input end Vs of the voltage stabilizing circuit is respectively connected with the reference voltage REF of the voltage stabilizing source Q1, the 2 pin of the capacitor C1 and the 2 pin of the capacitor C2, the cathode of the voltage stabilizing source Q1 is respectively connected with the 1 pin of the capacitor C2, the 1 pin of the resistor R6 and the cathode of the isolation optocoupler U1, the anode of the voltage stabilizing source Q1 is respectively connected with the negative end Vo-of the power output, the capacitor C1 is connected with the 2 pin of the resistor, the 1 pin of the resistor R5 is connected with the anode of the optoco;
the isolation optocoupler U1 is a linear optocoupler K10104D, and the voltage regulator source Q1 is TL 431;
sampling Vs (voltage source) of power output voltage, comparing the Vs with a reference voltage 2.5V of a TL431 voltage stabilizing circuit, and controlling the duty ratio of PWM (pulse-width modulation) of a control module by controlling the current of an input diode of an optocoupler U1; when the output voltage of the power supply is increased, the current of a diode flowing through the optocoupler is increased, the base light intensity of a phototriode in the optocoupler is increased, the CE junction breakover voltage of the phototriode is reduced and fed back to the input end COM of the control module, and the duty ratio of PWM is reduced in the control module, so that the output voltage of the power supply is reduced; similarly, when the power output voltage is increased, the PWM duty ratio is increased through the voltage stabilizing module and the control module, so that the power output voltage is increased.
As shown in fig. 3, the output overvoltage protection module includes an auxiliary power supply circuit, a voltage divider circuit, a second comparator circuit, and a third isolation circuit;
the input end of the second comparison circuit is connected with the output end of the voltage division circuit and the output end Vs of the voltage sampling circuit in the voltage stabilization module, the positive electrode of the power supply end of the second comparison circuit is connected with the output end Vc of the auxiliary power supply circuit, the negative electrode of the power supply end of the second comparison circuit is connected with the negative output end Vo-of the power supply, the output end of the second comparison circuit is connected with the positive electrode of the input end of the third isolation circuit, the positive input end of the auxiliary power supply circuit is connected with the positive output end of the power supply, the negative input end of the auxiliary power supply circuit is connected with the negative output end of the power supply, the input end of the voltage division circuit is respectively connected with the positive output end and the negative output end of the power supply;
the second comparison circuit comprises a comparator N3, a resistor R9, a resistor R24 and a resistor R10, wherein a power supply pin 8 of the comparator N3 is respectively connected with a pin 1 of the resistor R9, a pin 1 of the resistor R24 and power supply Vc, a power supply negative terminal pin 4 of the comparator N3 is connected with an output power Vo-, an anode of a voltage stabilizing diode D3, an input pin 5 of the comparator N3 is connected with an output end of the voltage dividing circuit, and an input pin 6 of the comparator N3 is respectively connected with a cathode of the voltage stabilizing diode D3 and a pin 2 of the resistor R24;
the voltage division circuit comprises a resistor R7, a resistor R8 and a capacitor C4, the input positive end of the voltage division circuit is respectively connected with the pin 1 of the resistor R7 and the positive end Vo + of the power output, the input negative end of the voltage division circuit is respectively connected with the pin 2 of the resistor R8 and the pin 2 of the capacitor C4, and the output end of the voltage division circuit is respectively connected with the pin 2 of the resistor R7, the pin 1 of the resistor R8 and the pin 1 of the capacitor C4;
the auxiliary power supply circuit comprises a resistor R4 and a voltage stabilizing diode D1, the input positive end of the auxiliary power supply circuit is respectively connected with the positive end Vo + of the output power supply and the pin 1 of the resistor R4, the input negative end of the auxiliary power supply circuit is respectively connected with the negative end Vo-of the output power supply and the anode of the voltage stabilizing diode D1, and the output end Vc of the auxiliary power supply circuit is respectively connected with the pin 2 of the resistor R4 and the cathode of the voltage stabilizing diode D1;
the auxiliary power supply circuit stabilizes the auxiliary power supply voltage Vc at a certain value after passing through the current-limiting resistor R4 and the voltage-stabilizing diode D1, and provides single power supply for the operational amplifier N3 and the operational amplifier N2. The second comparator input pin 6 has a constant voltage value of 5.1V, which is regulated by the resistor R24 and the 5.1V zener diode D3. The sampling voltage of the theoretical voltage division circuit is R8/(R8+ R7) × Vo + < 5.1V, and R8/(R8+ R7) × (Vo + +1V) > 5.1V when the output power supply is in overvoltage, wherein Vo + is a theoretical set value, so that resistance values of the resistor R7 and the resistor R8 are calculated; when the power supply outputs overvoltage, the second comparison circuit outputs high level, the high level passes through the current-limiting resistor R10 and the anode of the input diode of the isolation optocoupler U2, and the input UVLO voltage of the control module is pulled down by utilizing the photoelectric coupling conduction principle, so that PWM is turned off, and the inverter module is protected from being damaged.
As shown in fig. 4, the output overcurrent protection module is composed of a current sampling resistor, a reverse following and amplifying circuit, a first comparison circuit and a second isolation circuit;
the current sampling resistor is connected in series between the negative end Vo & lt- & gt of the power output, the input end of the current sampling resistor is connected with the negative end Vo & lt- & gt of the power output, the output end of the sampling circuit is connected with the negative end Vo & lt- & gt of the rectification and filtering of the output power and the input end of the reverse following circuit respectively, the positive end and the negative end of the input power supply of the reverse following circuit are connected with the output end Vc and the negative end Vo & lt- & gt of the power output of the auxiliary power supply circuit in the output overvoltage protection module respectively, the output end of the reverse following circuit is connected with the input end of the amplifying circuit, the output end of the amplifying circuit is connected with the input end of the first comparing circuit, the output end of the first comparing circuit is connected with the input;
the reverse follower circuit comprises an operational amplifier N2A, a resistor R23, a resistor R11, a resistor R12 and a capacitor C5, wherein an input end Vi of the reverse follower circuit is respectively connected with a pin 2 of a resistor R23 and a pin 1 of a capacitor C5, an output end of the reverse follower circuit is respectively connected with a pin 1 of a resistor R12 and an input end of an amplifying circuit, a power supply positive terminal 8 pin of the operational amplifier N2 is connected with an output end Vc of an auxiliary power supply circuit in the output overvoltage protection module, a power supply negative terminal 4 pin of the operational amplifier N2 is respectively connected with a negative terminal Vo of an output power supply, a pin 3 of an input end of an operational amplifier N2 and a pin 2 of a capacitor C5, an input pin 2 of the operational amplifier N2 is respectively connected with a pin 1 of a resistor R23 and a pin 2 of a resistor R11, and an output pin 1 of the operational amplifier N2 is respectively connected with a pin 2 of a;
the amplifying circuit comprises an operational amplifier N2B, a resistor R13, a resistor R14 and a resistor R15, wherein a pin 5 at the input end of the operational amplifier N2B is connected with a pin 1 of a resistor R12 in the reverse follower circuit, a pin 6 of an operational amplifier N2 is respectively connected with a pin 1 of the resistor R13 and a pin 2 of the resistor R14, a pin 2 of a resistor R13 is connected with a negative end Vo-of power output, a pin 7 of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R14 and a pin 2 of the resistor R15, and the output end of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R15 and the input end of the first comparison circuit;
the first comparison circuit comprises a comparator N3, a resistor R16, a resistor R17, a resistor R18 and a resistor R19, wherein a pin 3 at the input end of the comparator N3 is connected with a pin 1 of a resistor R15 in the amplification circuit, a pin 2 at the input end of the comparator N3 is respectively connected with a pin 2 of the resistor R17 and a pin 1 of the resistor R16, a pin 1 of the resistor R17 is respectively connected with a positive power output terminal Vo + and a pin 1 of the resistor R18, a pin 2 of the resistor R16 is connected with a negative power output terminal Vo-, a pin 1 at the output end of the comparator N3 is respectively connected with a pin 2 of the resistor R18 and a pin 2 of the resistor R19, and a pin 1 of the resistor R19 is connected with the input end of the second isolation circuit;
the second isolation circuit comprises an isolation optocoupler U3, a resistor R20 and a resistor R21, an input anode of the isolation optocoupler U3 is connected with an output end of the first comparison circuit, an input cathode of the isolation optocoupler U3 is connected with an output negative end, an output collector of the isolation optocoupler U3 is connected with an input end VREF of the control module, 2 pins of an output end emitter resistor R20 of the isolation optocoupler U3 are connected, 1 pin of the resistor R20, 1 pin of the resistor R21 and an input end CS of the control module are connected, and 2 pins of the resistor R21 are connected with an output power supply negative end Vo-.
The inversion module is an inversion circuit combining MOSFET or IGBT and isolation transformation.
The utility model discloses a theory of operation and mode:
the voltage collected by the current sampling Ri is a negative voltage Vi which is Ri Io, the sampling voltage Vi is filtered by a capacitor C5 and then is subjected to positive value acquisition by a (R23/R11)1:1 reverse follower, wherein the resistance values of a resistor R23 and a resistor R11 are the same, the sampling voltage Vi is amplified by an amplifying circuit by a certain multiple (R14+ R13)/R13 after being subjected to reverse follower, the maximum amplification voltage value-Ui (R14+ R13)/R13 is smaller than the power supply voltage Vc of the amplifying operational amplifier, the voltage value is compared with a certain voltage value Vc R16/(R16+ R17) of an input negative terminal in a first comparison circuit, when overcurrent is input, the sampled, reversely followed and amplified overcurrent voltage value-Ui (R14+ R13)/R13 is larger than the input negative terminal voltage value Vc R16/(R16+ R5), the first comparison circuit outputs a current limiting level R19 after being subjected to sampling, and the pull-up resistor R18 and the current limiting level R573 is output by a second comparison circuit, The isolation optocoupler U2, the voltage dividing resistor R20 and the voltage dividing resistor R21 input high level to the input end CS of the control module, so that PWM is rapidly turned off inside the control module, and the inverter module is protected.
The utility model discloses a power output protection circuit, when power output's voltage, electric current are for overflowing, excessive pressure, can detect rapidly and overflow or overvoltage signal to close the PWM ripples through control module, make contravariant module stop work, thereby improve the reliability of power, in addition, at power output's voltage, electric current non-excessive pressure, when overflowing, power module can self-starting, the utility model discloses simple structure, the reliability is high.
The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above description in any form, and although the present invention has been disclosed with reference to the preferred embodiment, it is not limited to the present invention, and any skilled person in the art can make modifications or changes equivalent to the equivalent embodiment of the above embodiments without departing from the scope of the present invention.
Claims (6)
1. An output protection circuit of a power supply is characterized by comprising a control module, a voltage stabilizing module, an output overvoltage protection module, an output overcurrent protection module and an inversion module;
the control module is respectively connected with the voltage stabilizing module, the output overvoltage protection module, the output overcurrent protection module and the inversion module;
the input ends COM, UVLO, CS and VREF of the control module are respectively connected with the output end COM of the voltage stabilizing module, the output end UVLO of the output overvoltage protection module and the output ends CS and VREF of the output overcurrent protection module, and the output end of the control module is connected with the input of the inverter module.
2. The output protection circuit of claim 1, wherein the control module is an analog power management chip or a DSP chip.
3. The output protection circuit of claim 1, wherein the voltage regulation module comprises a voltage sampling circuit, a voltage regulation circuit and a first isolation circuit;
the output end Vs of the voltage sampling circuit is connected with the input end of the voltage stabilizing circuit, and the output end of the voltage stabilizing circuit is connected with the input end of the first isolating circuit;
the first isolation circuit is connected with the input end of the control module;
the voltage sampling circuit comprises a resistor R1 and a resistor R2, the input end of the voltage sampling circuit is a power output positive end Vo +, a power output negative end Vo-, the power output positive end Vo + is connected with a pin 1 of the resistor R1, the power output negative end Vo-is connected with a pin 2 of the resistor R2, and the output end Vs of the voltage sampling circuit is respectively connected with a pin 2 of the resistor R1 and a pin 1 of the resistor R2;
the voltage stabilizing circuit comprises a resistor R5, a resistor R6, a capacitor C1, a capacitor C2, a voltage stabilizing source Q1 and an isolation optocoupler U1, wherein the input end of the voltage stabilizing circuit is respectively connected with a sampling voltage Vs of the output end of the voltage sampling circuit, a positive power output terminal Vo +, and a negative power output terminal Vo-, the input end Vs of the voltage stabilizing circuit is respectively connected with a reference voltage REF of a voltage stabilizing source Q1, a 2 pin of the capacitor C1, and a 2 pin of the capacitor C2, the cathode of the voltage stabilizing source Q1 is respectively connected with a 1 pin of the capacitor C2, a 1 pin of the resistor R6 and the cathode of the isolation optocoupler U1, the anode of the voltage stabilizing source Q1 is respectively connected with the negative power output terminal Vo-, the capacitor C1 is connected with the 2 pin of the resistor, the 1 pin of the resistor R5 is connected with the anode of the U1, and the 2 pin of the resistor R5 is connected;
the isolation optocoupler U1 is a linear optocoupler K10104D, and the voltage regulator source Q1 is TL 431.
4. The output protection circuit of claim 1, wherein the output overvoltage protection module comprises an auxiliary power supply circuit, a voltage division circuit, a second comparison circuit and a third isolation circuit;
the input end of the second comparison circuit is connected with the output end of the voltage division circuit and the output end Vs of the voltage sampling circuit in the voltage stabilization module, the positive electrode of the power supply end of the second comparison circuit is connected with the output end Vc of the auxiliary power supply circuit, the negative electrode of the power supply end of the second comparison circuit is connected with the negative output end Vo-of the power supply, the output end of the second comparison circuit is connected with the positive electrode of the input end of the third isolation circuit, the positive input end of the auxiliary power supply circuit is connected with the positive output end of the power supply, the negative input end of the auxiliary power supply circuit is connected with the negative output end of the power supply, the input end of the voltage division circuit is respectively connected with the positive output end and the negative output end of the power supply, and the output end of the third isolation;
the second comparison circuit comprises a comparator N3, a resistor R9, a resistor R24 and a resistor R10, wherein a power supply pin 8 of the comparator N3 is respectively connected with a pin 1 of the resistor R9, a pin 1 of the resistor R24 and power supply Vc, a power supply negative terminal pin 4 of the comparator N3 is connected with an output power Vo-, an anode of a voltage stabilizing diode D3, an input pin 5 of the comparator N3 is connected with an output end of a voltage dividing circuit, and an input pin 6 of the comparator N3 is respectively connected with a cathode of the voltage stabilizing diode D3 and a pin 2 of the resistor R24;
the voltage division circuit comprises a resistor R7, a resistor R8 and a capacitor C4, the input positive end of the voltage division circuit is respectively connected with a pin 1 of the resistor R7 and the positive end Vo + of the power output, the input negative end of the voltage division circuit is respectively connected with a pin 2 of the resistor R8 and a pin 2 of the capacitor C4, and the output end of the voltage division circuit is respectively connected with a pin 2 of the resistor R7, a pin 1 of the resistor R8 and a pin 1 of the capacitor C4;
the auxiliary power supply circuit comprises a resistor R4 and a voltage stabilizing diode D1, the input positive end of the auxiliary power supply circuit is respectively connected with the positive end Vo + of the output power supply and the pin 1 of the resistor R4, the input negative end of the auxiliary power supply circuit is respectively connected with the negative end Vo-of the output power supply and the anode of the voltage stabilizing diode D1, and the output end Vc of the auxiliary power supply circuit is respectively connected with the pin 2 of the resistor R4 and the cathode of the voltage stabilizing diode D1.
5. The output protection circuit of claim 1, wherein the output overcurrent protection module comprises a current sampling resistor, an inverse follower circuit, an amplifier circuit, a first comparator circuit, and a second isolation circuit;
the current sampling resistor is connected in series between the negative end Vo & lt- & gt of the power output, the negative end of the rectification filter of the output power supply, the input end of the current sampling resistor is connected with the negative end Vo & lt- & gt of the power output, the output end of the sampling circuit is connected with the negative end Vo & lt- & gt of the rectification filter of the output power supply and the input end of the reverse following circuit respectively, the positive end and the negative end of the input power supply of the reverse following circuit are connected with the output end Vc and the negative end Vo & lt- & gt of the power output of the auxiliary power supply circuit in the output overvoltage protection module respectively, the output end of the reverse following circuit is connected with the input end of the amplifying circuit, the output end of the amplifying circuit is connected with the input end of the first comparing circuit, the output end of the first comparing circuit;
the reverse follower circuit comprises an operational amplifier N2A, a resistor R23, a resistor R11, a resistor R12 and a capacitor C5, an input end Vi of the reverse follower circuit is respectively connected with a pin 2 of the resistor R23 and a pin 1 of the capacitor C5, an output end of the reverse follower circuit is respectively connected with a pin 1 of the resistor R12 and an input end of the amplification circuit, a power supply positive terminal 8 of the operational amplifier N2 is connected with an output end Vc of an auxiliary power supply circuit in the output overvoltage protection module, a power supply negative terminal 4 of the operational amplifier N2 is respectively connected with a negative pole Vo-, a pin 3 of an input end of the operational amplifier N2 and a pin 2 of the capacitor C5, an input pin 2 of the operational amplifier N2 is respectively connected with a pin 1 of the resistor R23 and a pin 2 of the resistor R11, and an output pin 1 of the operational amplifier N2 is respectively connected with a pin 2 of the resistor R12 and a pin 1 of the resistor R11;
the amplifying circuit comprises an operational amplifier N2B, a resistor R13, a resistor R14 and a resistor R15, wherein a pin 5 at the input end of the operational amplifier N2B is connected with a pin 1 of a resistor R12 in the reverse follower circuit, a pin 6 of the operational amplifier N2 is respectively connected with a pin 1 of the resistor R13 and a pin 2 of the resistor R14, a pin 2 of the resistor R13 is connected with a negative end Vo-of power output, a pin 7 of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R14 and a pin 2 of the resistor R15, and the output end of the operational amplifier N2B is respectively connected with a pin 1 of the resistor R15 and the input end of the first comparison circuit;
the first comparison circuit comprises a comparator N3, a resistor R16, a resistor R17, a resistor R18 and a resistor R19, wherein a pin 3 at the input end of the comparator N3 is connected with a pin 1 of a resistor R15 in the amplification circuit, a pin 2 at the input end of the comparator N3 is respectively connected with a pin 2 of the resistor R17 and a pin 1 of a resistor R16, a pin 1 of the resistor R17 is respectively connected with a pin Vo + of a power output positive terminal and a pin 1 of a resistor R18, a pin 2 of the resistor R16 is connected with a power output negative terminal Vo-, a pin 1 at the output end of the comparator N3 is respectively connected with a pin 2 of the resistor R18 and a pin 2 of the resistor R19, and a pin 1 of the resistor R19 is connected with the input end of the second isolation circuit;
the second isolation circuit comprises an isolation optocoupler U3, a resistor R20 and a resistor R21, an input anode of the isolation optocoupler U3 is connected with an output end of the first comparison circuit, an input cathode of the isolation optocoupler U3 is connected with an output negative end, a collector of an output end of the isolation optocoupler U3 is connected with an input end VREF of the control module, 2 pins of an output end emitter resistor R20 of the isolation optocoupler U3 are connected, 1 pin of the resistor R20, 1 pin of the resistor R21 and an input end CS of the control module are connected, and the 2 pins of the resistor R21 are connected with an output power supply negative end Vo-.
6. The output protection circuit of claim 1, wherein the inverter module is an inverter circuit combining a MOSFET or an IGBT and an isolation transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921832761.8U CN210724196U (en) | 2019-10-29 | 2019-10-29 | Output protection circuit of power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921832761.8U CN210724196U (en) | 2019-10-29 | 2019-10-29 | Output protection circuit of power supply |
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| CN210724196U true CN210724196U (en) | 2020-06-09 |
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| CN201921832761.8U Active CN210724196U (en) | 2019-10-29 | 2019-10-29 | Output protection circuit of power supply |
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| CN (1) | CN210724196U (en) |
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