CN220553928U - Low-cost slow start circuit - Google Patents
Low-cost slow start circuit Download PDFInfo
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- CN220553928U CN220553928U CN202322228130.8U CN202322228130U CN220553928U CN 220553928 U CN220553928 U CN 220553928U CN 202322228130 U CN202322228130 U CN 202322228130U CN 220553928 U CN220553928 U CN 220553928U
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- 239000003990 capacitor Substances 0.000 claims abstract description 42
- 230000001052 transient effect Effects 0.000 abstract description 6
- 230000006978 adaptation Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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Abstract
The utility model belongs to the technical field of slow start of a DC-DC power supply, and particularly relates to a low-cost slow start circuit which comprises a DC-DC power supply chip U1, a capacitor C2, a capacitor C1, a diode D1, a capacitor C4, an inductor L1 and a charging unit. According to the utility model, at the moment of power-on of an external power supply, as the voltages at the two ends of the charging unit cannot be suddenly changed, the voltage can be instantly regarded as short circuit, the enabling pin of the DC-DC power supply chip U1 is pulled up and is close to VIN, the DC-DC power supply chip U1 does not work, then the charging unit is charged through the internal pull-down resistor of the DC-DC power supply chip U1, when the voltages at the two ends of the charging unit are raised to a certain value, the voltage of the enabling pin of the DC-DC power supply chip U1 is lower than a starting threshold value, the DC-DC power supply chip U1 starts to work and starts to power-on, and the starting time of the DC-DC power supply chip U1 is different due to the fact that the charging unit values of all partial modules are different, so that distributed power-on of all modules is realized, and then transient current started simultaneously is reduced.
Description
Technical Field
The utility model belongs to the technical field of slow start of a DC-DC power supply, and particularly relates to a low-cost slow start circuit.
Background
The suction type smoke-sensing fire detector is an important device in the modern fire safety field, and is attracting attention due to its high sensitivity and high reliability in fire early warning. The detector can accurately detect the fire at the initial stage of the fire, thereby realizing early warning of the fire and powerfully guaranteeing the life and property safety of people. However, in practical application, the suction smoke-sensing fire detector requires larger power for starting a fan, a pump and the like, so that the suction smoke-sensing fire detector has higher requirements on the carrying capacity of a power supply.
Particularly, under the condition that a plurality of air suction type smoke-sensing fire detectors are started at the same time, because transient current required by the simultaneous starting of a plurality of devices is large, obvious impact can be generated on a power supply. In particular, during the start-up of these devices, transient overcurrents may cause the output protection mechanism of the direct current (DC-DC) power supply to trigger, which in turn causes the DC-DC power supply to output abnormally, such that the start-up of the fire detector suffers from failure.
Disclosure of Invention
The utility model aims to provide a low-cost slow starting circuit which can control a DC-DC power supply enabling pin of each module so as to delay the starting time of each DC-DC power supply module, thereby achieving the purpose of step-by-step power-up of each module and further reducing the transient current started simultaneously.
The technical scheme adopted by the utility model is as follows:
a low-cost slow start circuit comprises a DC-DC power supply chip U1, a capacitor C2, a capacitor C1, a diode D1, a capacitor C4, an inductor L1 and a charging unit;
the pin 1 of DC-DC power chip U1 is connected with the charging unit, one end of electric capacity C2 and one end of electric capacity C1, the pin 2 of DC-DC power chip U1 is connected with one end of diode D1 and one end of inductance L1, the pin 3 of DC-DC power chip U1 is connected with the other end of inductance L1 and one end of electric capacity C4, the pin 4 of DC-DC power chip U1 is connected with the charging unit, the pins 5, 6, 7 and 8 of DC-DC power chip U1 are all protected to ground, the other end of electric capacity C2 is connected with one end of electric capacity C1, the other end of diode D1 and the other end of electric capacity C4, the other end protection of diode D1 is grounded.
Further, the charging unit is a capacitor C3, one end of the capacitor C3 is connected with pin No. 1 of the DC-DC power chip U1, and the other end of the capacitor C3 is connected with pin No. 4 of the DC-DC power chip U1.
Further, the types of the capacitor C3 and the capacitor C2 are 0603.
Further, the capacitor C1 and the capacitor C4 are electrolytic capacitors.
Further, the diode D1 is a schottky diode.
Further, one end of the capacitor C4 is connected with a 5V power supply.
The utility model has the technical effects that:
according to the utility model, at the moment of power-on of an external power supply, as the voltages at the two ends of the charging unit cannot be suddenly changed, the voltage can be instantly regarded as short circuit, the enabling pin of the DC-DC power supply chip U1 is pulled up and is close to VIN, the DC-DC power supply chip U1 does not work, then the charging unit is charged through the internal pull-down resistor of the DC-DC power supply chip U1, when the voltages at the two ends of the charging unit are raised to a certain value, the voltage of the enabling pin of the DC-DC power supply chip U1 is lower than a starting threshold value, the DC-DC power supply chip U1 starts to work and starts to power-on, and the starting time of the DC-DC power supply chip U1 is different due to the fact that the charging unit values of all partial modules are different, so that distributed power-on of all modules is realized, and then transient current started simultaneously is reduced.
Drawings
Fig. 1 is a schematic circuit diagram of the present utility model.
Detailed Description
In order that the objects and advantages of the utility model will become more apparent, a more particular description of the utility model will be rendered by reference to specific embodiments thereof. It should be understood that the following text is used to describe only one or more specific embodiments of the present utility model and does not strictly limit the scope of protection of the specific claims.
As shown in FIG. 1, a low-cost slow start circuit comprises a DC-DC power chip U1, a capacitor C2, a capacitor C1, a diode D1, a capacitor C4, an inductor L1 and a charging unit;
the pin 1 of DC-DC power chip U1 is connected with the charging unit, one end of electric capacity C2 and one end of electric capacity C1, the pin 2 of DC-DC power chip U1 is connected with one end of diode D1 and one end of inductance L1, the pin 3 of DC-DC power chip U1 is connected with the other end of inductance L1 and one end of electric capacity C4, the pin 4 of DC-DC power chip U1 is connected with the charging unit, pins 5, 6, 7 and 8 of DC-DC power chip U1 are all protected to ground, the other end of electric capacity C2 is connected with one end of electric capacity C1, the other end of diode D1 and the other end of electric capacity C4, the other end of diode D1 is protected to ground.
Specifically, at the moment of power-up of the external power supply, as the voltages at the two ends of the charging unit cannot be suddenly changed, the voltage can be instantly regarded as a short circuit, the enabling pin of the DC-DC power supply chip U1 is pulled up and is close to VIN, the DC-DC power supply chip U1 does not work, then the charging unit is charged through the internal pull-down resistor of the DC-DC power supply chip U1, when the voltages at the two ends of the charging unit are raised to a certain value, the voltage of the enabling pin of the DC-DC power supply chip U1 is lower than a starting threshold value, the DC-DC power supply chip U1 starts to work, and power-up starting is started.
The capacitor C1 and the capacitor C4 are electrolytic capacitors, the diode D1 is a schottky diode, and one end of the capacitor C4 is connected to a 5V power supply.
In a preferred embodiment, the charging unit is a capacitor C3, one end of the capacitor C3 is connected to pin 1 of the DC-DC power chip U1, and the other end of the capacitor C3 is connected to pin 4 of the DC-DC power chip U1.
It should be noted that the types of the capacitor C3 and the capacitor C2 are 0603, the size of the components is small, the space of the PCB is saved, and the size of the circuit is reduced.
In this embodiment, at the moment of powering up the external power supply, since the voltage across the capacitor C3 cannot be suddenly changed, the moment can be regarded as a short circuit, the enable pin of the DC-DC power chip U1 is pulled up, close to VIN, the DC-DC power chip U1 does not operate, then the capacitor C3 is charged through the pull-down resistor inside the DC-DC power chip U1, when the voltage across the capacitor C3 is raised to a certain value, the voltage of the enable pin of the DC-DC power chip U1 is lower than the start threshold, and the DC-DC power chip U1 starts to operate and starts to power up.
It is worth mentioning that in actual products, voltage changes of 24V, 12V, 5V, 3.3V and the like exist in the equipment, different capacitances are selected for the capacitance C3 in the internal circuit of the inspiration type smoke-sensing fire disaster detector in each equipment according to the use requirement, classified triggering starting can be performed, step starting of the loads is achieved, and slow starting time is adjustable only by adjusting the size of the capacitance C3.
The working principle of the utility model is as follows: at the moment of power-on of an external power supply, as the voltages at two ends of the charging unit cannot be suddenly changed, the voltage can be instantly regarded as a short circuit, the enabling pin of the DC-DC power supply chip U1 is pulled up and is close to VIN, the DC-DC power supply chip U1 does not work, then the charging unit is charged through the internal pull-down resistor of the DC-DC power supply chip U1, when the voltages at two ends of the charging unit are raised to a certain value, the voltage of the enabling pin of the DC-DC power supply chip U1 is lower than a starting threshold value, the DC-DC power supply chip U1 starts to work and starts to power-on, and the starting time of the DC-DC power supply chip U1 is different due to the fact that the charging unit values of all the partial modules are different, so that distributed power-on of all the modules is realized, then transient current started at the same time is reduced, the components are fewer, the space of a PCB is saved, and the cost is reduced.
The foregoing is merely a preferred embodiment of the present utility model and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present utility model, which are intended to be comprehended within the scope of the present utility model. Structures, devices and methods of operation not specifically described and illustrated in the present application are all implemented by conventional means in the art unless specifically indicated and limited.
Claims (6)
1. The low-cost slow start circuit is characterized by comprising a DC-DC power supply chip U1, a capacitor C2, a capacitor C1, a diode D1, a capacitor C4, an inductor L1 and a charging unit;
the pin 1 of DC-DC power chip U1 is connected with the charging unit, one end of electric capacity C2 and one end of electric capacity C1, the pin 2 of DC-DC power chip U1 is connected with one end of diode D1 and one end of inductance L1, the pin 3 of DC-DC power chip U1 is connected with the other end of inductance L1 and one end of electric capacity C4, the pin 4 of DC-DC power chip U1 is connected with the charging unit, the pins 5, 6, 7 and 8 of DC-DC power chip U1 are all protected to ground, the other end of electric capacity C2 is connected with one end of electric capacity C1, the other end of diode D1 and the other end of electric capacity C4, the other end protection of diode D1 is grounded.
2. The low-cost slow start circuit according to claim 1, wherein the charging unit is a capacitor C3, one end of the capacitor C3 is connected to pin 1 of the DC-DC power chip U1, and the other end of the capacitor C3 is connected to pin 4 of the DC-DC power chip U1.
3. The low cost slow start circuit of claim 2, wherein the capacitor C3 and the capacitor C2 are each 0603 in type.
4. The low cost slow start circuit of claim 1, wherein the capacitor C1 and the capacitor C4 are electrolytic capacitors.
5. The low cost slow start circuit of claim 1, wherein the diode D1 is a schottky diode.
6. The low cost slow start circuit of claim 1, wherein one end of the capacitor C4 is connected to a 5V power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322228130.8U CN220553928U (en) | 2023-08-17 | 2023-08-17 | Low-cost slow start circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322228130.8U CN220553928U (en) | 2023-08-17 | 2023-08-17 | Low-cost slow start circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220553928U true CN220553928U (en) | 2024-03-01 |
Family
ID=90005919
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322228130.8U Active CN220553928U (en) | 2023-08-17 | 2023-08-17 | Low-cost slow start circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220553928U (en) |
-
2023
- 2023-08-17 CN CN202322228130.8U patent/CN220553928U/en active Active
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