CN213243521U - Power supply circuit - Google Patents
Power supply circuit Download PDFInfo
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- CN213243521U CN213243521U CN202021526834.3U CN202021526834U CN213243521U CN 213243521 U CN213243521 U CN 213243521U CN 202021526834 U CN202021526834 U CN 202021526834U CN 213243521 U CN213243521 U CN 213243521U
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Abstract
The utility model relates to a power supply circuit, which comprises a sampling circuit and a control output circuit; the sampling circuit comprises a resistor R1, a resistor R2, a resistor R4 and an integrated circuit IC1, when the reference terminal voltage of the integrated circuit IC1 is greater than a certain voltage threshold V1, the equivalent impedance between the cathode of the integrated circuit IC1 and the anode of the integrated circuit IC1 is reduced, and when the reference terminal voltage of the integrated circuit IC1 is less than a certain voltage threshold V2, the equivalent impedance between the cathode of the integrated circuit IC1 and the anode of the integrated circuit IC1 is increased; the control output circuit includes: diode D2 or voltage divider, switch Q1, resistor R3, switch Q2 and capacitor C1. The utility model discloses when integrated circuit IC1 reference end voltage is less than the threshold value of setting for, the voltage of output power supply port VDD is below the operating voltage of clamp to control IC to turn off switching power supply system fast, improve the stability of system.
Description
Technical Field
The utility model relates to a power supply circuit, in particular to power supply circuit that ability quick response.
Background
In the practical application of the switching power supply, when the switching power supply works, the power supply circuit provides working voltage for the control IC, the minimum voltage which is provided by the power supply circuit output power supply port VDD and meets the work requirement of the control IC is the working point of the control IC, when the working voltage provided by the power supply circuit for the control IC is greater than the working point, the control IC normally works, when the working voltage provided by the power supply circuit for the control IC is less than the working point, the control IC is turned off, and then the switching power supply is turned off, it can also be understood that the voltage provided by the power supply circuit at a certain moment is not enough to maintain the work of the switching power supply control IC, so that the effect of turning.
The power supply circuit in the prior art has the major defect of untimely turn-off, specifically, the sampling voltage detected by the control IC is reduced along with the reduction of the input voltage of the existing power supply circuit, when the control IC with under-voltage turn-off detects that the sampling voltage is lower than the threshold value set by the control IC, the control IC turns off the external driving capability of the control IC, the switch power supply system turns off, when the control IC with under-voltage turn-off detects that the sampling voltage is lower than the threshold value set by the control IC, the control IC theoretically should enter an under-voltage protection turn-off state, but the actual control IC has a turn-off delay phenomenon, so that the product cannot stop the output of the switch power supply in time at low voltage, the reliability of the.
SUMMERY OF THE UTILITY MODEL
In view of this, the to-be-solved technical problem of the present invention is to provide a power supply circuit, when the detected sampling voltage is lower than the threshold value set by itself, the voltage of the output power supply port VDD can be clamped to the operating point of the control IC in the twinkling of an eye, so as to rapidly turn off the switching power supply system, thereby thoroughly solving the above-mentioned major defect of the prior art that the power supply circuit is not turned off in time.
In order to solve the technical problem, the utility model provides a technical scheme as follows:
a power supply circuit, characterized by: the device comprises a sampling circuit, a control output circuit, a sampling port Vin, an auxiliary power supply port Vcc, an output power supply port VDD and a ground port GND;
the sampling circuit includes: resistor R1, resistor R2, resistor R4 and integrated circuit IC1, integrated circuit IC1 includes reference terminal, negative pole and positive pole, when integrated circuit IC1 reference terminal voltage is greater than certain voltage threshold V1, the equivalent impedance between the negative pole of integrated circuit IC1 to the positive pole of integrated circuit IC1 reduces, when integrated circuit IC1 reference terminal voltage is less than certain voltage threshold V2, the equivalent impedance between the negative pole of integrated circuit IC1 to the positive pole of integrated circuit IC1 increases;
the control output circuit includes: a diode D2 or a voltage divider, a switching tube Q1, a resistor R3, a switching tube Q2 and a capacitor C1;
the connection relationship is as follows:
one end of a resistor R1 is connected with a sampling port Vin, the other end of the resistor R1 is simultaneously connected with one end of a resistor R2 and a reference end of an integrated circuit IC1, one end of a resistor R4 is connected with an auxiliary power supply port Vcc, the other end of a resistor R4 is connected with a cathode of the integrated circuit IC1, and the other end of the resistor R2 and an anode of the integrated circuit IC1 are simultaneously connected with a ground port GND; one end of a resistor R3 is connected with an auxiliary power supply port Vcc, the other end of the resistor R3 is simultaneously connected with one end of a switch tube Q1 and a control end of a switch tube Q2, one end of the switch tube Q2 is connected with the auxiliary power supply port Vcc, the other end of the switch tube Q2 is connected with one end of a capacitor C1, and the other connection relations are one of the following two conditions:
(1) when the diode D2 is selected in the control output circuit, the control end of the switch tube Q1 is connected with the cathode of the integrated circuit IC1, the other end of the switch tube Q1 is connected with the cathode of the diode D2, and the anode of the diode D2 and the other end of the capacitor C1 are simultaneously connected with the ground port GND; or the control end of the switching tube Q1 is connected with the cathode of the diode D2, the anode of the diode D2 is connected with the cathode of the integrated circuit IC1, and the other end of the switching tube Q1 and the other end of the capacitor C1 are simultaneously connected to the ground port GND;
(2) when a voltage divider is selected in the control output circuit, the voltage divider comprises two resistors connected in series, one end of each resistor is one end of the voltage divider after the resistors are connected in series, the other end of each resistor is the other end of the voltage divider after the resistors are connected in series, the connection point of the two resistors is a voltage dividing point, the control end of the switch tube Q1 is connected with the voltage dividing point of the two resistors, one end of the voltage divider is connected with the cathode of the integrated circuit IC1, and the other end of the switch tube Q1 and the other end of the capacitor C1 at the other.
Preferably, the diode as the voltage dividing device is a zener diode.
Preferably, the switching tube Q1 and the switching tube Q2 are transistors or MOS transistors.
Preferably, the integrated circuit IC1 is TL 431.
As an improvement of the technical scheme, the method is characterized in that: the circuit also comprises a quick turn-off circuit which is a diode D4, the anode of the diode D4 is connected with the output power supply port VDD, and the cathode of the diode D4 is connected with the other end of the resistor R3.
As an improvement of the technical scheme, the method is characterized in that: the circuit further comprises a return difference design circuit, the return difference design circuit comprises a resistor R5 and a diode D1, the anode of the diode D1 is connected with the other end of the resistor R3, the cathode of the diode D1 is connected with one end of a resistor R5, and the other end of the resistor R5 is connected with the other end of the resistor R1.
Interpretation of terms:
one end of the switch tube is: the triode refers to a collector of the triode, the MOS tube refers to a drain of the MOS tube, and other types of switching tubes can be automatically corresponded by a person skilled in the art, which is not listed;
the other end of the switch tube is: the triode refers to an emitter of the triode, the MOS tube refers to a source of the MOS tube, and other types of switching tubes can be automatically corresponding by a person skilled in the art, which is not listed herein;
the control end of the switch tube: the base of the triode is referred to as the triode, the gate of the MOS transistor is referred to as the MOS transistor, and other types of switching tubes can be corresponded by persons skilled in the art, which is not listed here.
The working principle of the utility model is to be combined with specific embodiments for detailed analysis, which is not repeated herein. The utility model has the advantages as follows:
when using the control IC who contains the under-voltage shutdown function, all there is the time delay defect because of chip under-voltage detection and under-voltage shutdown output drive, so the utility model discloses below power supply port VDD's voltage clamp to control IC's operating voltage to turn off switching power supply system fast, improve the stability of system.
Drawings
Fig. 1 is a schematic diagram of a first embodiment of the power supply circuit of the present invention;
fig. 2 is a schematic diagram of a power supply circuit according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of a power supply circuit according to a third embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
First embodiment
Fig. 1 is a schematic diagram of a power supply circuit according to a first embodiment of the present invention, which includes a sampling circuit, a return difference design circuit, a control output circuit, a fast turn-off circuit, a sampling port Vin, an auxiliary power supply port Vcc, an output power supply port VDD, and a ground port GND;
the sampling circuit includes: a resistor R1, a resistor R2, a resistor R4 and an integrated circuit IC 1;
the return difference design circuit comprises: resistor R5 and diode D1;
the control output circuit includes: the diode D2, the switching tube Q1, the resistor R3, the switching tube Q2 and the capacitor C1;
the quick turn-off circuit includes: a diode D4;
the circuit connection relationship is as follows:
one end of a resistor R1 is connected with a sampling port Vin, the other end of the resistor R1 is simultaneously connected with one end of a resistor R2 and a reference end of an integrated circuit IC1, one end of a resistor R4 is connected with an auxiliary power supply port Vcc, the other end of a resistor R4 is connected with a cathode of the integrated circuit IC1, and the other end of the resistor R2 and an anode of the integrated circuit IC1 are simultaneously connected with a ground port GND;
one end of a resistor R3 is connected with a power supply port Vcc of an auxiliary power supply, the other end of the resistor R3 is simultaneously connected with one end of a switch tube Q1 and a control end of a switch tube Q2, one end of a switch tube Q2 is connected with the power supply port Vcc of the auxiliary power supply, the other end of a switch tube Q2 is connected with one end of a capacitor C1, a control end of a switch tube Q1 is connected with a cathode of an integrated circuit IC1, the other end of the switch tube Q1 is connected with a cathode of a diode D2, and an anode of the diode D2;
the anode of the diode D1 is connected with the other end of the resistor R3, the cathode of the diode D1 is connected with one end of the resistor R5, and the other end of the resistor R5 is connected with the other end of the resistor R1;
the anode of the diode D4 is connected to the output power supply port VDD, and the cathode of the diode D4 is connected to the other end of the resistor R3.
In this embodiment, the switching tube Q1 and the switching tube Q2 are triodes, and those skilled in the art may also select MOS tubes with switching properties; the integrated circuit IC1 of the present embodiment is TL431, but those skilled in the art may select other integrated circuits with the same function.
The working principle of the embodiment is as follows:
when the input voltage Vin decreases, the voltage of the connection point between the resistor R1 and the resistor R2 decreases, i.e., the voltage at the reference terminal of the integrated circuit IC1 decreases, when the voltage at the reference terminal of the integrated circuit IC1 is less than a certain voltage threshold V2, the equivalent impedance between the cathode of the integrated circuit IC1 and the anode of the integrated circuit IC1 increases, the cathode voltage of the integrated circuit IC1 is raised to be higher than the emitter voltage of the switching tube Q1, the switching tube Q1 is turned on, the collector voltage of the switching tube Q1 is pulled down to be lower than the working voltage of the control IC, the voltage of the output power supply port VDD is clamped to be lower than the working voltage of the control IC by the collector of the switching tube Q1, therefore, the switching power supply system is turned off quickly, the anode voltage of the diode D1 of the return difference design circuit is clamped to be low, the current from the return difference design circuit to the resistor R5 through the diode D1 is zero or very small, and the voltage provided by the return difference design circuit for the reference end of the integrated circuit IC1 is zero or very small.
On the contrary, when the voltage of the reference terminal of the integrated circuit IC1 is greater than a certain voltage threshold V1, the equivalent impedance between the cathode of the integrated circuit IC1 and the anode of the integrated circuit IC1 decreases, at this time, the switch Q1 is turned off, the auxiliary power supply port Vcc continues to provide the working voltage of the control IC to the output power supply port VDD through the switch Q2, at this time, the anode voltage of the diode D1 of the return difference design circuit increases, the current of the return difference design circuit from the diode D1 to the resistor R5 increases, and the voltage provided by the reference terminal of the integrated circuit IC1 by the return difference design circuit increases to V3, thereby generating the return difference voltage.
It should be noted that the function of the designed return difference circuit in this embodiment is that when the equivalent impedance between the cathode of the IC1 and the anode of the IC1 changes, the voltage provided by the designed return difference circuit to the reference terminal of the IC1 rises to V3, which can be eliminated in the application where the designed return difference circuit is not needed.
In addition, the function of the fast turn-off circuit in this embodiment is to clamp the voltage of the output power supply port VDD by the collector of the switching tube Q1 to be below the operating voltage of the control IC quickly, the charge of the capacitor C1 is released quickly through the diode D4 loop, if the diode D4 is removed, the power supply circuit can turn off the switching tube Q2 to achieve the purpose of turning off the switching power supply, the difference is that the charge of the capacitor C1 needs to be released slowly through other discharging loops, the voltage drop speed of the output power supply port VDD is slightly slow, and there is a certain turn-off delay, but it is still improved compared with the prior art.
Second embodiment
Fig. 2 is a schematic diagram of a second embodiment of the present invention, which is different from the first embodiment in that: a voltage divider composed of a resistor R6 and a resistor R7 is selected in the control output circuit, one end of the resistor R6 and the resistor R7 are connected in series is one end of the voltage divider, the other end of the resistor R4625 and the resistor R7 are connected in series is the other end of the voltage divider, the connection point of the two resistors is a voltage dividing point, the control end of the switch tube Q1 is connected with the voltage dividing point of the two resistors, one end of the voltage divider is connected with the cathode of the integrated circuit IC1, and the other end of the switch tube Q1 and the other end of the capacitor C.
The working principle of this embodiment is different from that of the first embodiment in that when the equivalent impedance between the cathode of the IC1 and the anode of the IC1 increases or decreases, the voltage at the voltage dividing point of the two resistors can be adjusted by changing the resistances of the resistor R6 and the resistor R7, so as to control the on/off of the switching tube Q1.
Third embodiment
Fig. 3 is a schematic diagram of a power supply circuit according to a third embodiment of the present invention, and as shown in the drawing, the present embodiment is different from the first embodiment in that: the connection relationship of the diode D2 is different, the control end of the switch tube Q1 is connected with the cathode of the diode D2, the anode of the diode D2 is connected with the cathode of the integrated circuit IC1, and the other end of the switch tube Q1 and the other end of the capacitor C1 are simultaneously connected with the ground port GND.
The working principle of the present embodiment is different from that of the first embodiment in that when the equivalent impedance between the cathode of the integrated circuit IC1 and the anode of the integrated circuit IC1 increases or decreases, the voltage regulation value of the diode D2 can still be set, so as to control the on/off of the switch tube Q1.
The above are only preferred embodiments of the present invention, and it should be noted that the above preferred embodiments should not be considered as limitations of the present invention. For those skilled in the art, a plurality of equivalent changes, improvements and decorations can be made without departing from the spirit and scope of the present invention, and these equivalent changes, improvements and decorations should be regarded as the protection scope of the present invention, which is not described in detail herein, and the protection scope of the present invention should be subject to the scope defined by the claims.
Claims (6)
1. A power supply circuit, characterized by: the device comprises a sampling circuit, a control output circuit, a sampling port Vin, an auxiliary power supply port Vcc, an output power supply port VDD and a ground port GND;
the sampling circuit includes: resistor R1, resistor R2, resistor R4 and integrated circuit IC1, integrated circuit IC1 includes reference terminal, negative pole and positive pole, when integrated circuit IC1 reference terminal voltage is greater than certain voltage threshold V1, the equivalent impedance between the negative pole of integrated circuit IC1 to the positive pole of integrated circuit IC1 reduces, when integrated circuit IC1 reference terminal voltage is less than certain voltage threshold V2, the equivalent impedance between the negative pole of integrated circuit IC1 to the positive pole of integrated circuit IC1 increases;
the control output circuit includes: a diode D2 or a voltage divider, a switching tube Q1, a resistor R3, a switching tube Q2 and a capacitor C1;
the connection relationship is as follows:
one end of a resistor R1 is connected with a sampling port Vin, the other end of the resistor R1 is simultaneously connected with one end of a resistor R2 and a reference end of an integrated circuit IC1, one end of a resistor R4 is connected with an auxiliary power supply port Vcc, the other end of a resistor R4 is connected with a cathode of the integrated circuit IC1, and the other end of the resistor R2 and an anode of the integrated circuit IC1 are simultaneously connected with a ground port GND; one end of a resistor R3 is connected with an auxiliary power supply port Vcc, the other end of the resistor R3 is simultaneously connected with one end of a switch tube Q1 and a control end of a switch tube Q2, one end of the switch tube Q2 is connected with the auxiliary power supply port Vcc, the other end of the switch tube Q2 is connected with one end of a capacitor C1, and the other connection relations are one of the following two conditions:
when the diode D2 is selected in the control output circuit, the control end of the switch tube Q1 is connected with the cathode of the integrated circuit IC1, the other end of the switch tube Q1 is connected with the cathode of the diode D2, and the anode of the diode D2 and the other end of the capacitor C1 are simultaneously connected with the ground port GND; or the control end of the switching tube Q1 is connected with the cathode of the diode D2, the anode of the diode D2 is connected with the cathode of the integrated circuit IC1, and the other end of the switching tube Q1 and the other end of the capacitor C1 are simultaneously connected to the ground port GND;
when a voltage divider is selected in the control output circuit, the voltage divider comprises two resistors connected in series, one end of each resistor is one end of the voltage divider after the resistors are connected in series, the other end of each resistor is the other end of the voltage divider after the resistors are connected in series, the connection point of the two resistors is a voltage dividing point, the control end of the switch tube Q1 is connected with the voltage dividing point of the two resistors, one end of the voltage divider is connected with the cathode of the integrated circuit IC1, and the other end of the switch tube Q1 and the other end of the capacitor C1 at the other.
2. The power supply circuit of claim 1, wherein: the diode as a voltage divider is a zener diode.
3. The power supply circuit of claim 1, wherein: the switching tube Q1 and the switching tube Q2 are triodes or MOS tubes.
4. The power supply circuit of claim 1, wherein: integrated circuit IC1 is TL 431.
5. The power supply circuit of claim 1, wherein: the circuit also comprises a quick turn-off circuit which is a diode D4, the anode of the diode D4 is connected with the output power supply port VDD, and the cathode of the diode D4 is connected with the other end of the resistor R3.
6. The power supply circuit of claim 1, wherein: the circuit further comprises a return difference design circuit, the return difference design circuit comprises a resistor R5 and a diode D1, the anode of the diode D1 is connected with the other end of the resistor R3, the cathode of the diode D1 is connected with one end of a resistor R5, and the other end of the resistor R5 is connected with the other end of the resistor R1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021526834.3U CN213243521U (en) | 2020-07-29 | 2020-07-29 | Power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021526834.3U CN213243521U (en) | 2020-07-29 | 2020-07-29 | Power supply circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213243521U true CN213243521U (en) | 2021-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021526834.3U Active CN213243521U (en) | 2020-07-29 | 2020-07-29 | Power supply circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213243521U (en) |
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2020
- 2020-07-29 CN CN202021526834.3U patent/CN213243521U/en active Active
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