CN212627673U - Switching power supply circuit and charger - Google Patents
Switching power supply circuit and charger Download PDFInfo
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- CN212627673U CN212627673U CN202021596919.9U CN202021596919U CN212627673U CN 212627673 U CN212627673 U CN 212627673U CN 202021596919 U CN202021596919 U CN 202021596919U CN 212627673 U CN212627673 U CN 212627673U
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Abstract
The utility model relates to a power supply circuit technical field relates to a switching power supply circuit and charger very much. The utility model discloses a switching power supply circuit and charger, wherein, switching power supply circuit includes power control chip and voltage feedback loop, the output voltage of this switching power supply circuit of input termination of voltage feedback loop, the output termination of voltage feedback loop power control chip's feedback input, be equipped with thermistor in the voltage feedback loop, thermistor is set up to when the temperature rise of this switching power supply circuit's power device, make power control chip's feedback input's voltage reduce correspondingly. The utility model discloses can carry out work as far as possible under the circumstances of guaranteeing self safe and reliable according to ambient temperature automatically regulated output capacity, and simple structure easily realizes, and is with low costs.
Description
Technical Field
The utility model belongs to the technical field of power supply circuit, specifically relate to a switching power supply circuit and charger.
Background
The switching power supply has advantages of high conversion efficiency, small size, light weight, and the like, and is widely applied to various electric devices, for example, various chargers. When the switching power supply works at a high power, a power device of the switching power supply can generate more heat, and the heat is generally discharged by a radiator and an air cooling system, so that the failure of the power device due to overhigh temperature is avoided.
If the air cooling system fails, for example, the fan does not work, the power device is likely to fail due to overhigh temperature, so from the perspective of reliability, the switching power supply needs to ensure that the system is not damaged under the condition that the air cooling system fails during design.
The existing general methods mainly comprise two types: one method is to provide a temperature sensor, embed the temperature sensor in the transformer, and close the output when the temperature of the transformer exceeds a certain range, which has the disadvantages that the transformer process becomes complicated and the cost is increased; the other method is to lock a temperature switch on the radiator directly, when the temperature exceeds a certain value, the temperature switch is switched off, and a power supply loop of the power supply control chip is cut off.
Disclosure of Invention
An object of the utility model is to provide a switching power supply circuit and charger are used for solving the technical problem that above-mentioned exists.
In order to achieve the above object, the utility model adopts the following technical scheme: a switch power supply circuit comprises a power supply control chip and a voltage feedback loop, wherein the input end of the voltage feedback loop is connected with the output voltage of the switch power supply circuit, the output end of the voltage feedback loop is connected with the feedback input end of the power supply control chip, a thermistor is arranged in the voltage feedback loop, and the thermistor is set to correspondingly reduce the voltage of the feedback input end of the power supply control chip when the temperature of a power device of the switch power supply circuit is increased.
Further, the thermistor is disposed beside the power device of the switching power supply circuit to perform heat transfer.
Further, the voltage feedback loop comprises an optical coupler IC9, a resistor R11 and a thermistor NTC3, an input end of the optical coupler IC9 is connected in series with the thermistor NTC3 and then connected between an output positive end and an output negative end of the switching power supply circuit, a resistor R11 and the thermistor NTC3 are arranged in parallel, an output positive end of the optical coupler IC9 is connected with a feedback input end of the power supply control chip, and an output negative end series resistor R59 of the optical coupler IC9 is grounded.
Furthermore, the voltage feedback loop further comprises a voltage division circuit and a controllable precise voltage-stabilizing source, wherein the input end of the voltage division circuit is connected with the output voltage of the switching power supply circuit, the output end of the voltage division circuit is connected with the reference electrode of the controllable precise voltage-stabilizing source, the anode of the controllable precise voltage-stabilizing source is connected with the output negative electrode of the switching power supply circuit, the cathode series resistor R21 of the controllable precise voltage-stabilizing source is connected with the output positive electrode of the switching power supply circuit, and the two ends of the thermistor NTC3 are respectively connected with the anode and the cathode of the controllable precise voltage-stabilizing source.
Furthermore, the voltage dividing circuit comprises resistors R23, R29 and R27, the resistors R23 and R27 are connected in series and then connected between the output positive end and the output negative end of the switching power supply circuit, the resistor R29 and the resistor R23 are arranged in parallel, and the node between the resistors R23 and R27 is connected with the reference electrode of the controllable precision voltage stabilizing source.
Furthermore, the device also comprises a resistor R22, a capacitor C8 and a capacitor C10, wherein the resistor R22 and the capacitor C10 are connected in series and then are connected between the cathode and the reference electrode of the controllable precision voltage-stabilizing source, and the capacitor C8 is connected in parallel with the resistor R22 and the capacitor C10 which are connected in series.
Further, the optical coupler IC9 is of a phototransistor output type.
Further, the switching power supply circuit is a flyback switching power supply circuit.
Furthermore, the model of the power control chip is UC 3843.
The utility model also provides a charger is equipped with foretell switching power supply circuit.
The utility model has the advantages of:
the utility model discloses a fuse into voltage feedback loop with thermistor, can carry out work as far as possible under the circumstances of guaranteeing self safe and reliable according to ambient temperature automatically regulated output capacity, and simple structure, easily realize, it is with low costs.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a circuit diagram of an embodiment of the present invention.
Detailed Description
To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The present invention will now be further described with reference to the accompanying drawings and detailed description.
As shown in FIG. 1, a switching power supply circuit comprises a power supply control chip IC1 and a voltage feedback loop, wherein the input end of the voltage feedback loop is connected with the output voltage of the switching power supply circuit, the output end of the voltage feedback loop is connected with the feedback input end of a power supply control chip IC1, a thermistor NTC3 is arranged in the voltage feedback loop, and the thermistor NTC3 is arranged to make the voltage of the feedback input end of the power supply control chip IC1 correspondingly reduced when the temperature of a power device of the switching power supply circuit is increased, so that the duty ratio of a PWM control signal output by the power supply control chip IC1 is correspondingly reduced, the output voltage of the switching power supply circuit is reduced, and the output load capacity is reduced.
The utility model discloses a fuse into voltage feedback loop with thermistor, can carry out work as far as possible under the circumstances of guaranteeing self safe and reliable according to ambient temperature automatically regulated output capacity, and simple structure, easily realize, it is with low costs.
In this embodiment, the switching power supply circuit is a single-tube flyback switching power supply circuit, and includes transformers T1A, T1B and MOS transistors Q1 (power devices), and the specific circuit connection relationship is shown in fig. 1 in detail, which is not described in detail, but is not limited thereto.
In this embodiment, the model of the power control chip IC1 is UC3843, the 1 st pin of the power control chip IC1 is a feedback input terminal, the 6 th pin is a PWM control signal output terminal, and the 6 th pin is connected to the gate of the MOS transistor Q1, but the invention is not limited thereto, and in other embodiments, the power control chip IC1 may also be implemented by using other models or types of power control chip IC 1.
In this embodiment, the pin 6 of the power control chip IC1 is connected to the gate of the MOS transistor Q1 through the parallel resistors R6 and R9, and is used to prevent parasitic oscillation caused by the gate-source lead inductance of the MOS transistor Q1.
In this embodiment, the thermistor NTC3 is disposed on the PCB and beside the MOS transistor Q1 for heat transfer, thereby improving the heat transfer effect and the temperature detection sensitivity.
In this specific embodiment, the voltage feedback loop includes a voltage dividing circuit, a controllable precise voltage-stabilizing power supply IC4, an optical coupler IC9, a resistor R11 and a thermistor NTC3, an input end of the optical coupler IC9 is connected in series with the thermistor NTC3 and then connected between an output positive terminal BAT + and an output negative terminal BAT-of the switching power supply circuit, a resistor R11 is connected in parallel with the thermistor NTC3, an output positive terminal of the optical coupler IC9 is connected with a 1 st pin of the power supply control chip IC1, and an output negative terminal series resistor R59 of the optical coupler IC9 is grounded.
The input end of the voltage dividing circuit is connected with the output voltage of the switch power supply circuit, the output end of the voltage dividing circuit is connected with the reference pole of the controllable precise voltage-stabilizing source IC4, the anode of the controllable precise voltage-stabilizing source IC4 is connected with the output negative pole BAT of the switch power supply circuit, the cathode series resistor R21 of the controllable precise voltage-stabilizing source IC4 is connected with the output positive pole BAT + of the switch power supply circuit, and the two ends of the thermistor NTC3 are respectively connected with the anode and the cathode of the controllable precise voltage-stabilizing source IC 4.
In this embodiment, the controllable precision voltage regulator IC4 is model TL431, which is easy to implement, reliable in performance, and low in cost, but not limited thereto.
In this embodiment, the voltage dividing circuit includes resistors R23, R29, and R27, the resistors R23 and R27 are connected in series and then connected between an output positive terminal BAT + and an output negative terminal BAT —, the resistor R29 and the resistor R23 are connected in parallel, and a node between the resistors R23 and R27 is connected to a reference electrode of the controllable precision voltage-stabilizing power supply IC 4. The voltage dividing circuit has simple structure, easy realization and low cost, but not limited to this, in other embodiments, the voltage dividing circuit can also be realized by other existing voltage dividing circuits.
Preferably, in this embodiment, the current limiter further includes a resistor R22, a capacitor C8 and a capacitor C10, the resistor R22 and the capacitor C10 are connected in series and then connected between a cathode and a reference electrode of the controllable precision voltage regulator IC4, and the capacitor C8 is connected in parallel with the resistor R22 and the capacitor C10 which are connected in series, so as to perform filtering processing, thereby preventing the optocoupler IC9 from acting too fast.
In this embodiment, the optocoupler IC9 is a phototransistor output type, and the model is TLP781, but the optocoupler IC is not limited thereto, and in this embodiment, other types of optocouplers may be used to implement the optocoupler.
The working process is as follows:
when the air cooling system is abnormal or the ambient temperature exceeds the rated range, the resistance of the thermistor NTC3 is reduced remarkably, the current flowing through the diode of the optical coupler IC9 is increased, the current at the output end of the optical coupler IC9 is increased, the voltage of the 1 st pin of the power supply control chip IC1 is pulled down, the duty ratio of the PWM control signal output by the 6 th pin of the power supply control chip IC1 is correspondingly reduced, the output voltage of the switching power supply circuit is reduced accordingly, the output load capacity is reduced accordingly until the dynamic balance at a new temperature can be reached, or the whole output is closed until the whole output is closed, the automatic output regulation capacity according to the ambient temperature is realized, the work (such as charging) is carried out as far as possible under the condition of ensuring the self safety and reliability, the structure is simple, the realization is easy, and the cost.
The utility model also provides a charger is equipped with foretell switching power supply circuit.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The utility model provides a switching power supply circuit, includes power control chip and voltage feedback loop, and the input termination of voltage feedback loop is this switching power supply circuit's output voltage, and the output termination of voltage feedback loop is power control chip's feedback input end, its characterized in that: a thermistor is arranged in the voltage feedback loop, and the thermistor is set to enable the voltage of the feedback input end of the power supply control chip to correspondingly reduce when the temperature of the power device of the switching power supply circuit is increased.
2. The switching power supply circuit according to claim 1, wherein: the thermistor is arranged beside the power device of the switching power supply circuit for heat transfer.
3. The switching power supply circuit according to claim 1, wherein: the voltage feedback loop comprises an optical coupler IC9, a resistor R11 and a thermistor NTC3, the input end of the optical coupler IC9 is connected between the output positive end and the output negative end of the switching power supply circuit after being connected with the thermistor NTC3 in series, a resistor R11 and the thermistor NTC3 are arranged in parallel, the output positive end of the optical coupler IC9 is connected with the feedback input end of the power supply control chip, and the output negative end of the optical coupler IC9 is connected with a series resistor R59 in ground.
4. The switching power supply circuit according to claim 3, wherein: the voltage feedback loop further comprises a voltage division circuit and a controllable precise voltage-stabilizing source, the input end of the voltage division circuit is connected with the output voltage of the switching power supply circuit, the output end of the voltage division circuit is connected with the reference electrode of the controllable precise voltage-stabilizing source, the anode of the controllable precise voltage-stabilizing source is connected with the output negative electrode of the switching power supply circuit, the cathode series resistor R21 of the controllable precise voltage-stabilizing source is connected with the output positive electrode of the switching power supply circuit, and the two ends of the thermistor NTC3 are respectively connected with the anode and the cathode of the controllable precise voltage-stabilizing source.
5. The switching power supply circuit according to claim 4, wherein: the voltage division circuit comprises resistors R23, R29 and R27, wherein the resistors R23 and R27 are connected in series and then connected between the output positive end and the output negative end of the switching power supply circuit, the resistor R29 and the resistor R23 are arranged in parallel, and the node between the resistors R23 and R27 is connected with the reference electrode of the controllable precise voltage stabilization source.
6. The switching power supply circuit according to claim 5, wherein: the high-voltage direct current power supply further comprises a resistor R22, a capacitor C8 and a capacitor C10, the resistor R22 and the capacitor C10 are connected in series and then connected between a cathode and a reference electrode of the controllable precision voltage stabilizing source, and the capacitor C8 is connected with the resistor R22 and the capacitor C10 which are connected in series in parallel.
7. The switching power supply circuit according to claim 3, wherein: the optical coupler IC9 is of a phototriode output type.
8. The switching power supply circuit according to claim 1, wherein: the switching power supply circuit is a flyback switching power supply circuit.
9. The switching power supply circuit according to claim 8, wherein: the model of the power supply control chip is UC 3843.
10. A charger, characterized by: a switching power supply circuit according to any one of claims 1 to 9 is provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021596919.9U CN212627673U (en) | 2020-08-05 | 2020-08-05 | Switching power supply circuit and charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021596919.9U CN212627673U (en) | 2020-08-05 | 2020-08-05 | Switching power supply circuit and charger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212627673U true CN212627673U (en) | 2021-02-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021596919.9U Active CN212627673U (en) | 2020-08-05 | 2020-08-05 | Switching power supply circuit and charger |
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|---|---|
| CN (1) | CN212627673U (en) |
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- 2020-08-05 CN CN202021596919.9U patent/CN212627673U/en active Active
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Denomination of utility model: A switching power supply circuit and charger Effective date of registration: 20210908 Granted publication date: 20210226 Pledgee: Bank of China Limited by Share Ltd. Xiamen branch Pledgor: Xiamen haisuo Technology Co., Ltd Registration number: Y2021980009066 |