CN213243813U - Power supply soft start circuit - Google Patents
Power supply soft start circuit Download PDFInfo
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- CN213243813U CN213243813U CN202022168198.8U CN202022168198U CN213243813U CN 213243813 U CN213243813 U CN 213243813U CN 202022168198 U CN202022168198 U CN 202022168198U CN 213243813 U CN213243813 U CN 213243813U
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Abstract
The utility model discloses a soft start circuit of power for loop control among the switching power supply, including the charging circuit that diode D2 and electric capacity C2 constitute and the discharging circuit that diode D1 and electric capacity C2 constitute, produce the output voltage that slowly rises through the charging circuit to and discharge through the discharging circuit when the power outage, make soft start circuit keep normal work. The utility model discloses can realize power loop control's soft start, solved because power management IC when switching from the open loop to the closed loop, because the start output hiccup that loop response speed problem leads to falls the electricity in the output, and output is not monotonous to rise or output overshoot phenomenon.
Description
Technical Field
The utility model relates to the field of electronic technology, especially, relate to a starting circuit of power.
Background
Fig. 1 is a schematic circuit diagram of an existing optocoupler feedback control circuit, when isolation feedback is realized by using the circuit shown in fig. 1, due to different application environments, such as a limit working temperature, a capacitive load, a peak load, repeated continuous start, and the like, when a conventional power supply is started particularly under a heavy load condition, an output voltage slowly rises, a loop is in an open loop state, a switching tube works at the maximum duty ratio at the moment, the current of the switching tube continuously increases, and at the moment, a power chip may be subjected to start protection or hiccup due to a large peak current, so that the circuit cannot normally work.
Therefore, a circuit which can adapt to various working conditions and can normally work is urgently needed so as to improve the reliability of a power supply.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a power supply soft start circuit can realize power loop control's soft start, has solved because power management IC when switching from the open loop to the closed loop, because the start output hiccup that loop response speed problem leads to, the output falls the electricity, and output is monotonously ascending or the output phenomenon of overshooting.
The utility model provides a first technical scheme does:
a power supply soft start circuit is used for loop control in a switching power supply, and is characterized in that: the voltage stabilizing device comprises a resistor R, a capacitor C, an optocoupler diode U, a voltage stabilizing source U, a diode D and a diode D, wherein one end of the resistor R is connected with a power supply V, the other end of the resistor R is connected with an anode of the optocoupler diode U, a cathode of the optocoupler diode U is connected with a cathode K of the voltage stabilizing source U, an anode A of the voltage stabilizing source U is grounded, one end of the resistor R is connected with a cathode K of the voltage stabilizing source U, the other end of the resistor R is connected with one end of the capacitor C, the other end of the capacitor C is connected with a reference end R of the voltage stabilizing source U, one end of the resistor R is connected with an output end Vo, the other end of the resistor R is grounded, the anode of the diode D is connected with the cathode K of the voltage.
As a preferred embodiment of the above technical means, the present invention is characterized in that: a resistor R5 is connected between the anode of the diode D2 and the cathode K of the voltage regulator U2.
The utility model provides a second technical scheme does:
a power supply soft start circuit is used for loop control in a switching power supply, and is characterized in that: the LED driving circuit comprises a resistor R, a capacitor C, an optocoupler diode U, a voltage stabilizing source U and a diode D, wherein one end of the resistor R is connected with a power supply V, the other end of the resistor R is connected with an optocoupler diode U anode, the optocoupler diode U cathode is connected with a voltage stabilizing source U cathode K, a voltage stabilizing source U anode A is grounded, one end of the resistor R is connected with a voltage stabilizing source U cathode K, the other end of the resistor R is connected with one end of the capacitor C, the other end of the capacitor C is connected with a voltage stabilizing source U reference end R, one end of the resistor R is connected with an output port Vo, the other end of the resistor R is connected with one ends of the voltage stabilizing source U reference end R and the resistor R, the other end of the resistor R is.
As a preferred embodiment of the above technical means, the present invention is characterized in that: a resistor R5 is connected between the anode of the diode D2 and the cathode K of the voltage regulator U2.
The utility model has the advantages that: when the power supply is started and the output voltage slowly rises, a starting current is provided for the optocoupler diode U1 through the diode D2 and the capacitor C2 charging loop, so that the loop is in a controllable state, and the current of the switching tube is not continuously increased; when the power supply is cut off, the soft start circuit works normally through a diode D1 and a capacitor C2 discharge loop.
Drawings
Fig. 1 is a schematic diagram of a circuit of a conventional optocoupler feedback control circuit;
fig. 2 is a schematic diagram of a power supply soft start circuit according to a first embodiment of the present invention;
fig. 3 is a schematic diagram of a first embodiment of the present invention for improving a power supply soft start circuit;
fig. 4 is a schematic diagram of a power supply soft start circuit according to a second embodiment of the present invention;
fig. 5 is a schematic diagram of a second embodiment of the present invention.
Detailed Description
First embodiment
As shown in fig. 2, the soft start circuit for a power supply of this embodiment includes a resistor R, a capacitor C, an optocoupler diode U, a regulator U, a diode D, and a diode D, wherein one end of the resistor R is connected to a power supply V, the other end of the resistor R is connected to an anode of the optocoupler diode U, a cathode of the optocoupler diode U is connected to a cathode K of the regulator U, an anode a of the regulator U is grounded, one end of the resistor R is connected to a cathode K of the regulator U, the other end of the resistor R is connected to one end of the capacitor C, the other end of the capacitor C is connected to a reference terminal R of the regulator U, one end of the resistor R is connected to an output port Vo, the other end of the resistor R is connected to a reference terminal R of the regulator U and one end of the resistor R, the other, the cathode of the diode D1 is connected to the output Vo.
The working process of the power supply soft start circuit is as follows: at the moment of starting the power supply, a capacitor C2 of the power supply soft start circuit is charged through a diode D2, the output voltage rises slowly, and when the power supply soft start circuit works in a steady state, the output voltage is determined by a resistor R2 and a resistor R3; when the power supply is powered off, the capacitor C2 discharges through the diode D1, so that the soft start circuit can still work normally when the soft start circuit is started after the power supply is powered off.
The working principle of the power supply soft start circuit is as follows: when the power supply is powered on, the capacitor of the soft start circuit is charged, and the output voltage slowly rises; when the soft start circuit works in a steady state, the soft start circuit does not work, and the output voltage is determined by the divider resistor; when the power supply is powered off, the capacitor of the soft start circuit discharges through the discharge loop, so that the soft start circuit can still work normally when the soft start circuit is started after the power supply is powered off.
In addition, a resistor R5 is added between the anode of the diode D2 and the cathode K of the regulator U2, as shown in fig. 3, not only can the same function as the above embodiment be realized, but also the addition of the resistor R5 can facilitate the power supply soft start circuit to adjust the charging current of the capacitor C2 according to the actual working state, so as to adjust the soft start speed of the circuit.
Second embodiment
As shown in fig. 4, a power supply soft start circuit for the present embodiment includes a resistor R1, a capacitor C1, an optocoupler diode U1, a voltage regulator U1, and a diode D1, one end of the resistor R1 is connected to the power supply V1, the other end of the resistor R1 is connected to an anode of the optocoupler diode U1, a cathode of the optocoupler diode U1 is connected to a cathode K of the voltage regulator U1, an anode a of the voltage regulator U1 is grounded, one end of the resistor R1 is connected to the cathode K of the voltage regulator U1, one end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to a reference terminal R of the voltage regulator U1, one end of the resistor R1 is connected to an output terminal Vo, the reference terminal R1 of the voltage regulator U1 and one end of the resistor R1, the cathode of the voltage regulator U1 is connected to one, the other end of the capacitor C2 and the other end of the resistor R6 are grounded.
The working principle of this embodiment is the same as that of the first embodiment, except that the discharging loop is directly discharged through the resistor R6, the structure of this embodiment is simpler, and the cost is lower.
In addition, a resistor R5 is added between the anode of the diode D2 and the cathode K of the regulator U2, as shown in fig. 5, not only can the same function as the above embodiment be realized, but also the addition of the resistor R5 can facilitate the power supply soft start circuit to adjust the charging current of the capacitor C2 according to the actual working state, so as to adjust the soft start speed of the circuit.
The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of equivalent substitutions, improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations are also considered as the protection scope of the present invention.
Claims (4)
1. A power supply soft start circuit is used for loop control in a switching power supply, and is characterized in that: the voltage stabilizing device comprises a resistor R, a capacitor C, an optocoupler diode U, a voltage stabilizing source U, a diode D and a diode D, wherein one end of the resistor R is connected with a power supply V, the other end of the resistor R is connected with an anode of the optocoupler diode U, a cathode of the optocoupler diode U is connected with a cathode K of the voltage stabilizing source U, an anode A of the voltage stabilizing source U is grounded, one end of the resistor R is connected with a cathode K of the voltage stabilizing source U, the other end of the resistor R is connected with one end of the capacitor C, the other end of the capacitor C is connected with a reference end R of the voltage stabilizing source U, one end of the resistor R is connected with an output end Vo, the other end of the resistor R is grounded, the anode of the diode D is connected with the cathode K of the voltage.
2. The power supply soft start circuit of claim 1, wherein: a resistor R5 is connected between the anode of the diode D2 and the cathode K of the voltage regulator U2.
3. A power supply soft start circuit is used for loop control in a switching power supply, and is characterized in that: the LED driving circuit comprises a resistor R, a capacitor C, an optocoupler diode U, a voltage stabilizing source U and a diode D, wherein one end of the resistor R is connected with a power supply V, the other end of the resistor R is connected with an optocoupler diode U anode, the optocoupler diode U cathode is connected with a voltage stabilizing source U cathode K, a voltage stabilizing source U anode A is grounded, one end of the resistor R is connected with a voltage stabilizing source U cathode K, the other end of the resistor R is connected with one end of the capacitor C, the other end of the capacitor C is connected with a voltage stabilizing source U reference end R, one end of the resistor R is connected with an output port Vo, the other end of the resistor R is connected with one ends of the voltage stabilizing source U reference end R and the resistor R, the other end of the resistor R is.
4. A power supply soft start circuit as claimed in claim 3, wherein: a resistor R5 is connected between the anode of the diode D2 and the cathode K of the voltage regulator U2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022168198.8U CN213243813U (en) | 2020-09-28 | 2020-09-28 | Power supply soft start circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022168198.8U CN213243813U (en) | 2020-09-28 | 2020-09-28 | Power supply soft start circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213243813U true CN213243813U (en) | 2021-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022168198.8U Active CN213243813U (en) | 2020-09-28 | 2020-09-28 | Power supply soft start circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213243813U (en) |
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2020
- 2020-09-28 CN CN202022168198.8U patent/CN213243813U/en active Active
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