CN218940939U - Direct-current power supply slow start circuit - Google Patents

Abstract

The utility model relates to the technical field of power supply, in particular to a slow starting circuit of a direct-current power supply. The detecting circuit is used for receiving an external input voltage and forming a driving voltage output under the condition that the external input voltage is matched with a preset voltage; and the slow start circuit is connected with the detection circuit and is used for forming a power supply voltage output according to the external input voltage under the condition of receiving the driving voltage and the external input voltage.

Description

Direct-current power supply slow start circuit

Technical Field

The utility model relates to the technical field of power supply, in particular to a slow starting circuit of a direct-current power supply.

Background

The direct-current power supply slow start circuit can effectively reduce the impact of the circuit on the power supply during power-on, avoid abnormal and even damaged work of other unit circuits in the system caused by serious voltage drop, and is a necessary component especially in communication equipment supporting hot plug, centralized power supply equipment and equipment or circuits needing midway start work. The direct-current power supply slow-start circuit is a circuit which is frequently used in a direct-current power supply circuit, and generally uses a MOS tube as a switching element. In actual use, as the on-voltage of the MOS tube is different and the rising time of the input power supply voltage is also different, the surge current of the slow start circuit is not adopted as shown in fig. 1. Thus, the VDS ID can be maintained at a larger power value for a certain time, so that the MOS tube is burnt.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model provides a direct-current power supply slow start circuit, in particular to a direct-current power supply slow start circuit: comprising the steps of (a) a step of,

the detection circuit is used for receiving an external input voltage and forming a driving voltage output under the condition that the external input voltage is matched with a preset voltage;

and the slow start circuit is connected with the detection circuit and is used for forming a power supply voltage output according to the external input voltage under the condition of receiving the driving voltage and the external input voltage.

Preferably, the above-mentioned dc power supply slow start circuit, wherein the detection circuit includes:

the sampling branch circuit comprises a sampling branch circuit, wherein two ends of the sampling branch circuit are respectively connected with the external input voltage, and a sampling end for forming sampling voltage is arranged in the sampling branch circuit;

the input end of the detector is connected with the sampling end, the detector works in a voltage stabilizing state under the condition that the sampling voltage is not smaller than the preset voltage, and the detector works in a conducting state under the condition that the sampling voltage is smaller than the preset voltage;

and the control end of the output branch is connected with the output end of the detector, and the output branch outputs the driving voltage when the detector works in a voltage stabilizing state.

Preferably, the above-mentioned slow start circuit for a dc power supply, wherein the slow start circuit includes:

the control end of the slow-start control branch is connected with the output end of the output branch, the input end of the slow-start control branch is connected with the negative voltage end of the external input voltage, and the output end of the slow-start control branch is connected with the low voltage end of the external circuit;

the high voltage end of the external circuit is connected with the positive voltage end of the external input voltage.

Preferably, in the above dc power supply slow start circuit, the sampling branch includes a first voltage dividing resistor, and a second voltage dividing resistor connected in series with the first voltage dividing resistor, and the sampling end is formed between the first voltage dividing resistor and the second voltage dividing resistor.

Preferably, in the above dc power supply slow start circuit, the detector is a reference voltage source, and a second pin of the reference voltage source is connected to the sampling end.

Preferably, in the above dc power supply slow start circuit, the output branch is formed by a triode, a base electrode of the triode is connected to a first pin of the reference voltage source, and an emitter electrode of the triode is connected to a third pin of the reference voltage source; and the collector electrode of the triode is connected with the positive voltage end of the external input voltage, and forms the output end of the output branch.

Preferably, the above-mentioned slow start circuit for a dc power supply, wherein the slow start circuit includes:

the control branch of slow start is formed by an NMOS tube, and the grid electrode of the NMOS tube is connected with the output end of the output branch.

Compared with the prior art, the utility model has the beneficial effects that:

through the direct-current power supply slow start circuit, the power-on time of the power supply can be prolonged through the NMOS tube conduction delay, especially under the application occasion supporting hot plug, when a single board is inserted, the contact between the single board and a motherboard contact pin is unstable, and in order to avoid the influence of jitter, a circuit can be added between a power supply module and a motherboard power supply, so that the input voltage is delayed for a period of time to be electrified, and the electrified impact current is reduced: because the single board power supply is connected with the filter capacitor, when the power supply is electrified and jumps instantly, larger impact current can be generated due to the charging of the capacitor, so that the voltage of the motherboard power supply shakes, falls and strong electromagnetic radiation can easily cause adverse effects on the single boards in other works, and if the power supply electrifying speed is slowed down, the effects can be effectively reduced.

Drawings

For a better understanding and to set forth of some embodiments of the present application, reference will now be made to the description of embodiments taken in conjunction with the accompanying drawings in which like reference numerals identify corresponding parts throughout.

FIG. 1 is a schematic diagram of a current surge for a slow start circuit without using a DC power supply;

fig. 2 is a schematic diagram of a dc power supply slow start circuit according to an embodiment of the present utility model;

fig. 3 is a schematic diagram of current surge using a dc power source slow start circuit according to an embodiment of the present utility model.

Detailed Description

The following description with reference to the accompanying drawings is provided to facilitate a comprehensive understanding of the various embodiments of the present application defined by the claims and their equivalents. These embodiments include various specific details for ease of understanding, but these are to be considered exemplary only. Accordingly, those skilled in the art will appreciate that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present application. In addition, descriptions of well-known functions and constructions will be omitted herein for brevity and clarity of description.

The terms and phrases used in the following specification and claims are not limited to a literal sense, but rather are only used for the purpose of clarity and consistency in understanding the present application. Thus, it will be appreciated by those skilled in the art that the descriptions of the various embodiments of the present application are provided for illustration only and not for the purpose of limiting the application as defined by the appended claims and their equivalents.

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which embodiments of the present application are shown, it being apparent that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The utility model provides a slow starting circuit of a direct-current power supply, in particular to a slow starting circuit of a direct-current power supply, which comprises the following components: comprising the steps of (a) a step of,

the detection circuit is used for receiving an external input voltage and forming a driving voltage output under the condition that the external input voltage is matched with a preset voltage; further, the detection circuit specifically includes:

the sampling branch circuit comprises a sampling branch circuit, wherein two ends of the sampling branch circuit are respectively connected with the external input voltage, and a sampling end for forming sampling voltage is arranged in the sampling branch circuit; the sampling branch circuit comprises a first voltage dividing resistor and a second voltage dividing resistor connected with the first voltage dividing resistor in series, and the sampling end is formed between the first voltage dividing resistor and the second voltage dividing resistor. The first voltage dividing resistor is formed by connecting a third resistor R3 and a fourth resistor R4 in series, the second voltage dividing resistor is formed by a ninth resistor R9, and the sampling end is formed between the fourth resistor R4 and the ninth resistor R9.

The input end of the detector is connected with the sampling end, the detector works in a voltage stabilizing state under the condition that the sampling voltage is not smaller than the preset voltage, and the detector works in a conducting state under the condition that the sampling voltage is smaller than the preset voltage; illustratively, the detector is a reference voltage source U2, and a second pin of the reference voltage source U2 is connected to the sampling end. The first pin of the reference voltage source U2 is connected with the positive voltage end of the external input voltage through an eleventh resistor R11.

And the control end of the output branch is connected with the output end of the detector, and the output branch outputs the driving voltage when the detector works in a voltage stabilizing state. The output branch is formed by a triode Q1, the base electrode of the triode Q1 is connected with the first pin of the reference voltage source, and the emitter electrode of the triode Q1 is connected with the third pin of the reference voltage source U2; the collector of the triode Q1 is connected with the positive voltage end of the external input voltage, and the collector of the triode Q1 forms the output end of the output branch. Further, a second resistor R2 is connected between the second pin and the third pin of the triode Q1, and a first resistor R1 is connected between the second pin of the triode Q1 and the positive voltage end of the external input voltage. The two ends of the second resistor R2 are connected with a first capacitor C1 in parallel.

The slow start circuit is connected with the detection circuit and is used for forming a power supply voltage output according to the external input voltage under the condition of receiving the driving voltage and the external input voltage, and the slow start circuit comprises:

the control end of the slow-start control branch is connected with the output end of the output branch, the input end of the slow-start control branch is connected with the negative voltage end of the external input voltage, and the output end of the slow-start control branch is connected with the low voltage end of the external circuit; further, the control branch of slow start is formed by an NMOS tube VD14, and a gate of the NMOS tube VD14 is connected to an output end of the output branch.

The high voltage end of the external circuit is connected with the positive voltage of the external input voltage.

Further, the direct-current power supply slow start circuit further comprises a reverse protection diode, wherein the input end of the reverse protection diode is connected with the slow start circuit, and the output end of the reverse protection diode is connected with the detection circuit.

The working principle of the direct-current power supply slow start circuit is as follows:

under the action of an external input voltage signal, the third resistor, the fourth resistor and the ninth resistor perform voltage division processing on the external input voltage, the voltage value formed on the ninth resistor is the sampling voltage, the reference voltage source U2 obtains the sampling voltage, the reference voltage source U2 is conducted under the condition that the sampling voltage is smaller than the preset voltage, the output branch circuit and the slow starting circuit at the rear end are short-circuit-protected at the moment, the reference voltage source U2 works in a voltage stabilizing state under the condition that the sampling voltage is not smaller than the preset voltage, the base voltage of the triode Q1 is the stable voltage of the reference voltage source U2, the stable voltage drives the triode Q1 to be conducted, the voltage at the forward end of the diode VD2 is the voltage of the voltage stabilizing diode VD1, the grid voltage of the NMOS tube VD14 is the sum of the conduction voltage drops of the diode VD2 and the driving triode Q1, the NMOS tube is conducted relatively smaller, and the NMOS tube begins to be conducted until the external input voltage is transmitted under the condition that the NMOS tube is completely conducted as shown in FIG. 3.

Through the direct-current power supply slow start circuit, the power-on time of the power supply can be prolonged through the NMOS tube conduction delay, especially under the application occasion supporting hot plug, when a single board is inserted, the contact between the single board and a motherboard contact pin is unstable, and in order to avoid the influence of jitter, a circuit can be added between a power supply module and a motherboard power supply, so that the input voltage is delayed for a period of time to be electrified, and the electrified impact current is reduced: because the single board power supply is connected with the filter capacitor, when the power supply is electrified and jumps instantly, larger impact current can be generated due to the charging of the capacitor, so that the voltage of the motherboard power supply shakes, falls and strong electromagnetic radiation can easily cause adverse effects on the single boards in other works, and if the power supply electrifying speed is slowed down, the effects can be effectively reduced.

The foregoing disclosure is only illustrative of some of the preferred embodiments of the present application and is not intended to limit the scope of the claims hereof, as persons of ordinary skill in the art will understand that all or part of the processes for accomplishing the foregoing embodiments may be practiced with equivalent changes which may be made by the claims herein and which fall within the scope of the utility model.

Claims (8)

1. A slow start circuit of a DC power supply is characterized by comprising,

the detection circuit is used for receiving an external input voltage and forming a driving voltage output under the condition that the external input voltage is matched with a preset voltage;

and the slow start circuit is connected with the detection circuit and is used for forming a power supply voltage output according to the external input voltage under the condition of receiving the driving voltage and the external input voltage.

2. The slow start circuit of claim 1, wherein the detection circuit comprises:

the sampling branch circuit comprises a sampling branch circuit, wherein two ends of the sampling branch circuit are respectively connected with the external input voltage, and a sampling end for forming sampling voltage is arranged in the sampling branch circuit;

the input end of the detector is connected with the sampling end, the detector works in a voltage stabilizing state under the condition that the sampling voltage is not smaller than the preset voltage, and the detector works in a conducting state under the condition that the sampling voltage is smaller than the preset voltage;

and the control end of the output branch is connected with the output end of the detector, and the driving voltage is output when the detector works in a voltage stabilizing state.

3. The slow start circuit of claim 2, wherein the slow start circuit comprises:

the control end of the slow-start control branch is connected with the output end of the output branch, the input end of the slow-start control branch is connected with the negative voltage end of the external input voltage, and the output end of the slow-start control branch is connected with the low voltage end of the external circuit;

the high voltage end of the external circuit is connected with the positive voltage end of the external input voltage.

4. The slow start circuit of claim 2, wherein the sampling branch circuit comprises a first voltage dividing resistor and a second voltage dividing resistor connected in series with the first voltage dividing resistor, and the sampling end is formed between the first voltage dividing resistor and the second voltage dividing resistor.

5. The slow start circuit of claim 2, wherein the detector is a reference voltage source, and a second pin of the reference voltage source is connected to the sampling end.

6. The slow start circuit of claim 5, wherein the output branch is formed by a triode, a base electrode of the triode is connected with a first pin of the reference voltage source, and an emitter electrode of the triode is connected with a third pin of the reference voltage source; and the collector electrode of the triode is connected with the positive voltage end of the external input voltage, and forms the output end of the output branch.

7. A dc power slow start circuit as set forth in claim 3, wherein said slow start circuit comprises:

the control branch of slow start is formed by an NMOS tube, and the grid electrode of the NMOS tube is connected with the output end of the output branch.

8. The slow start circuit of claim 1, further comprising a reverse protection diode, wherein an input terminal of the reverse protection diode is connected to the slow start circuit, and an output terminal of the reverse protection diode is connected to the detection circuit.

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