WO2016184026A1

WO2016184026A1 - Circuit for slowly starting power supply loop to discharge electricity

Info

Publication number: WO2016184026A1
Application number: PCT/CN2015/092219
Authority: WO
Inventors: 韩冲
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-05-19
Filing date: 2015-10-19
Publication date: 2016-11-24
Also published as: CN106301332A; CN106301332B

Abstract

The present invention provides a circuit configured to slowly start a power supply loop to discharge electricity. The circuit comprises: a charging circuit, a discharging circuit and a switching circuit configured to slowly start. The charging circuit is connected to the discharging circuit and the switching circuit, and the discharging circuit is connected to the switching circuit. The charging circuit is configured to slowly start a power supply loop to supply power. During power failure or hot swapping, the discharging circuit is configured to discharge electricity from the switching circuit. The present invention solves the problem of slow discharging of a main loop MOS tube in a slow start circuit in the related art.

Description

Circuit for slow start power supply circuit discharge

Technical field

The present invention relates to the field of circuits, and in particular to a circuit for slowly starting discharge of a power supply loop.

Background technique

Once the communication device is interrupted, the large-scale network and economic loss will occur. Therefore, more and more communication devices require the replacement of the faulty board without powering down the whole machine. This requires the device port power supply loop to support the hot swap function, and the large inrush current generated during the hot plug process is likely to cause a series of faults in the electronic device.

1 is a schematic diagram of a slow-start hot-swap power supply circuit in the related art, and FIG. 2 is a waveform diagram of an input voltage and a gate voltage of a main-circuit MOS transistor in the related art in the case of power-down, according to FIG. 1 and FIG. The gate voltage of the main loop MOS transistor VT1 cannot be quickly lowered to zero. Especially in the latter half of the discharge, the discharge is too slow, so that VT1 can not be turned off immediately, and then the power will be generated immediately, which will generate a large inrush current, affecting the main circuit MOS tube VT1, insurance FU1 and the pre-stage power supply line, and the circuit is reliable. The reduction in sex, the limitation of VT1 selection is also large, and the cost is high.

In view of the slow discharge of the main circuit MOS tube in the slow start circuit in the related art, an effective solution has not been proposed yet.

Summary of the invention

The main object of the embodiments of the present invention is to provide a circuit for slowly starting the discharge of the power supply circuit, so as to at least solve the problem that the main circuit MOS tube discharges slowly in the slow start circuit of the related art.

According to an aspect of an embodiment of the present invention, a circuit for slowly starting a power supply circuit discharge is provided, the circuit comprising: a charging circuit, a discharging circuit, and a switching circuit configured to be slowly activated, the charging circuit and the discharging The circuit is connected to the switch circuit, and the discharge circuit is connected to the switch circuit; the charging circuit is configured to supply power to the slow start power supply loop; when the power is off or hot swapped, the discharge circuit is set to be opposite The switching circuit is discharged.

Optionally, the charging circuit includes: a first diode and a first capacitor, the discharging circuit includes: a second diode, a second capacitor, a switching transistor, a first MOS transistor, and a first resistor; The switching circuit includes: a second MOS transistor of the main circuit; the first terminal A is connected to the gate of the second MOS transistor, and the B terminal of the first capacitor is connected to the source of the second MOS transistor; The first diode A is connected to the second terminal of the first capacitor and the second MOS transistor, and the B terminal of the first diode is connected to an external power source and is the first capacitor. And supplying power to the second MOS transistor; the B terminal of the second diode is connected to a power source, and the A terminal of the second diode is respectively connected to the A terminal of the second capacitor and the emitter of the switching transistor Connecting, a base of the switching transistor is connected to an A terminal of the first diode, a collector of the switching transistor is connected to a gate of the first MOS transistor, and a source of the first MOS transistor Connected to a B terminal of the second capacitor and a source of the second MOS transistor, respectively, a drain of the first MOS transistor and the first diode A end and the second MOS transistor a gate connection; the first resistor is connected in parallel with the first capacitor, and is configured to discharge the first capacitor when power is off or hot swap.

Optionally, the discharge circuit further includes: a second resistor; the second resistor is disposed between the second capacitor and the switch transistor, and is configured to adjust a discharge time of the power supply loop.

Optionally, the discharge circuit further includes: a third resistor; the third resistor is disposed between a drain of the first MOS transistor and a base of the switch transistor, and is disposed to the first MOS The tube is restricted.

Optionally, the charging circuit further includes a voltage dividing circuit, and the voltage dividing circuit is configured to perform voltage division protection on the power supply circuit.

Optionally, the voltage dividing circuit includes: a fourth resistor and a fifth resistor; one end of the fourth resistor is connected to the power source, and the other end is connected to the B end of the first diode and the second diode Connected to the B terminal; one end of the fifth resistor is connected to the B end of the first diode and the B end of the second diode, and the other end is connected to the B end of the second capacitor, the first MOS The tube is connected to a source of the second MOS transistor.

Optionally, the circuit further includes a protection circuit, one end is connected to the power source, and the other end is respectively connected to the discharge circuit and the charging circuit, and is configured to perform voltage regulation protection on the power supply circuit.

Optionally, the protection circuit is composed of a voltage stabilizing tube; one end of the voltage stabilizing tube is connected to a common end of the fourth and the fifth resistors, and the other end is connected to a B end of the second capacitor, The first MOS transistor and the source of the second MOS transistor are connected.

Optionally, the first capacitor and the second capacitor are of the same capacity level.

Optionally, the switching transistor is a PNP switching transistor.

According to the embodiment of the present invention, a discharge circuit is disposed in the circuit of the slow start power supply circuit, and the discharge circuit is configured to discharge the switch circuit during power failure or hot plugging, and solves the related art in the related art. The main circuit MOS tube in the circuit discharges slowly.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing in:

1 is a schematic diagram of a slow start hot plug power supply circuit in the related art;

2 is a waveform diagram of an input voltage and a gate voltage of a main circuit MOS transistor when power is off in the related art;

3 is a structural block diagram of a circuit for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

4 is a circuit diagram 1 for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

5 is a block diagram showing an optional structure of a circuit for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

6 is a circuit diagram 2 for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

7 is a block diagram 2 of an alternative structure of a circuit for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

8 is a circuit diagram 3 for slowly starting a power supply circuit discharge according to an embodiment of the present invention;

9 is a first schematic diagram of a DC power slow-start circuit according to an alternative embodiment of the present invention;

10 is a second schematic diagram of a DC power slow-start circuit according to an alternative embodiment of the present invention;

11 is a schematic diagram showing the input voltage and the gate voltage waveform of the main loop MOS transistor when the slow start circuit is powered down according to an alternative embodiment of the present invention.

detailed description

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments.

The embodiment of the present invention provides a circuit for slowly starting the discharge of the power supply circuit. FIG. 3 is a structural block diagram of a circuit for slowly starting the discharge of the power supply circuit according to an embodiment of the present invention. As shown in FIG. 3, the circuit includes: a charging circuit 32, a discharging circuit 34, and a switching circuit 36 provided as a slow start, the charging circuit 32 is connected to the discharging circuit 34 and the switching circuit 36, and the discharging circuit 34 is connected to the switching circuit 36;

The charging circuit 32 is configured to supply power to the slow start power supply circuit;

The discharge circuit 34 is arranged to discharge the switch circuit 36 during power down or hot swap.

According to the embodiment of the present invention, a discharge circuit is disposed in the circuit of the slow start power supply circuit, and the discharge circuit is used for discharging the switch circuit during power failure or hot plugging, and solves the related art in the slow start circuit in the related art. The main loop MOS tube discharges slowly.

4 is a circuit diagram 1 for slow start power supply circuit discharge according to an embodiment of the present invention. As shown in FIG. 4, the charging circuit 32 includes a first diode D1 and a first capacitor C2, and the discharge circuit 34 includes: Diode D2 a second capacitor C1, a switching transistor VT1, a first MOS transistor VT2, and a first resistor R5; the switching circuit 36 includes: a main loop second MOS transistor VT3;

The A terminal of the first capacitor C2 is connected to the gate of the second MOS transistor VT3, and the B terminal of the C2 of the first capacitor is connected to the source of the second MOS transistor VT3, and the A terminal of the first diode D1 and the first capacitor respectively The A terminal of the C2 is connected to the gate of the second MOS transistor VT3, and the B terminal of the first diode D1 is connected to the external power supply and supplies power to the first capacitor C2 and the second MOS transistor VT3;

The B terminal of the second diode D2 is connected to the power source, and the A terminal of the second diode D2 is respectively connected to the A terminal of the second capacitor C1 and the emitter of the switching transistor VT1, and the base of the switching transistor VT1 is first and second. The A terminal of the diode D1 is connected, the collector of the switching transistor VT1 is connected to the gate of the first MOS transistor VT2, and the sources of the first MOS transistor VT2 are respectively connected to the B terminal of the second capacitor C1 and the source of the second MOS transistor VT3. a pole connection, a drain of the first MOS transistor VT2 is respectively connected to an A terminal of the first diode D1 and a gate of the second MOS transistor VT3;

The first resistor R5 is connected in parallel with the first capacitor C2 and is arranged to discharge the first capacitor when power is off or hot swap.

Optionally, the discharge circuit further includes: a second resistor; wherein the second resistor is disposed between the second capacitor switch transistor and configured to adjust a discharge time of the power supply loop.

Optionally, the discharge circuit further includes: a third resistor; the third resistor is disposed between the drain of the first MOS transistor and the base of the switch transistor, and is configured to limit the current MOSFET.

5 is an optional structural block diagram of a circuit for slowly starting a power supply circuit discharge according to an embodiment of the present invention. As shown in FIG. 5, the charging circuit 32 further includes a voltage dividing circuit 38, and the voltage dividing circuit 38 is set to a power supply circuit. Perform partial pressure protection.

6 is a circuit diagram for slow start power supply circuit discharge according to an embodiment of the present invention, as shown in FIG. 6, the voltage dividing circuit 38 includes: a fourth resistor R1 and a fifth resistor R2;

One end of the fourth resistor R1 is connected to the power source, and the other end is connected to the B end of the first diode D1 and the B end of the second diode D2;

One end of the fifth resistor R2 is connected to the B terminal of the first diode D1 and the B terminal of the second diode D2, and the other end is connected to the B terminal of the second capacitor C1, the first MOS transistor VT2 and the second MOS transistor VT3. The source is connected.

7 is a block diagram showing an optional structure of a circuit for slowly starting a power supply circuit discharge according to an embodiment of the present invention. As shown in FIG. 7, the circuit further includes a protection circuit 40, one end is connected to the power source, and the other end is connected to the charging circuit 32. The discharge circuits 34 are respectively connected and arranged to regulate the power supply circuit.

FIG. 8 is a circuit diagram 3 for slowly starting the discharge of the power supply circuit according to an embodiment of the present invention, as shown in FIG. The protection circuit is composed of a Zener diode VD1; one end of the Zener diode is connected to the common end of the fourth and fifth resistors, and the other end is connected to the B terminal of the second capacitor, the source of the first MOS transistor and the second MOS transistor.

In an optional implementation manner of this embodiment, the first capacitor and the second capacitor are of the same capacity level, and the switching transistor is a PNP switch transistor.

The present invention is exemplified below in conjunction with an optional embodiment of the embodiments of the present invention;

The optional embodiment provides a circuit for accelerating the gate discharge of the main circuit MOS transistor in the slow start circuit, and the circuit includes: a charging circuit, a fast discharging circuit, a protection circuit and a switching circuit. The main loop MOS tube is located in the switch circuit, and the fast discharge circuit quickly discharges the gate voltage of the main loop MOS tube when the input is powered down.

FIG. 9 is a first schematic diagram of a DC power supply slow start circuit according to an alternative embodiment of the present invention, and FIG. 10 is a second schematic diagram of a DC power supply slow start circuit according to an alternative embodiment of the present invention.

In addition to the slow-start MOS transistor VT3 connected in series on the negative voltage loop, the optional embodiment further includes:

The power-on charging circuit is composed of a voltage dividing resistor R1, R2, a charging diode D1, and a gate capacitor C2, and the charging diode D2 charges the capacitor C1;

Shutdown detection and fast discharge circuit: consists of capacitors C1, R3, PNP switch transistors VT1, R4, discharge MOS tube VT2, discharge resistor R5.

Protection circuit: consists of voltage regulator tube VD1.

In the following, taking FIG. 9 as an example, the optional embodiment is described in detail. The circuit starting circuit is similar to the common slow start circuit. After the voltage dividing resistors R1 and R2 are divided, the voltage regulator is protected by VD1, and the main circuit MOS is fed through the diode D1. The gate-source capacitor C2 of VT3 is charged, the gate-source voltage rises slowly, and the main loop MOS transistor switches from the pinch-off region to the ohmic region via the constant current region, so that the output of the latter stage is slowly established, and the purpose of reducing the inrush current on the line is achieved; C1 is charged by D2, C1 and C2 are of the same capacity level, and the transistor VT1 is not turned on; when power is off or hot swapped, C2 is first discharged through the resistor R5, and the voltage is lower than the voltage drop of a launch junction of C1. After VT1 is turned on, C1 quickly drives the discharge MOS transistor VT2 to turn on, directly shorting the gate source of the main loop MOS transistor to the ground, and the discharge current is large and can be put to zero. R3 is set to adjust the discharge time, and R4 is set to the discharge MOS tube current limit. Through the slow start circuit of FIG. 9, the input voltage and the gate voltage waveform of the main loop MOS transistor when the circuit slow start circuit is powered down are as shown in FIG. 11, and FIG. 11 is a slow start circuit according to an alternative embodiment of the present invention. Schematic diagram of the input voltage and the gate voltage waveform of the main loop MOS transistor.

With the optional embodiment, during the process of frequent hot plugging and unplugging of the DC power supply board, the MOS transistor can be quickly turned off in the power supply loop at the moment of power failure, thereby greatly reducing the impact generated during the hot plugging process. The current improves the reliability of the whole system equipment, and solves the problem that the main circuit MOS tube discharges slowly in the slow start circuit in the related art, and increases the number of devices compared with the circuit in the related art, and basically does not increase the board area, and is suitable for high Density Layout occasions.

The above is only an alternative embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

According to the embodiment of the present invention, a discharge circuit is disposed in the circuit of the slow start power supply circuit, and the discharge circuit is used for discharging the switch circuit during power failure or hot plugging, and solves the related art in the related art. The main circuit MOS tube in the circuit discharges slowly.

Claims

A circuit for slowly starting a discharge of a power supply circuit, the circuit comprising: a charging circuit, a discharging circuit, and a switching circuit for slow start, the charging circuit being connected to the discharging circuit and the switching circuit, the discharging a circuit connected to the switch circuit;

The charging circuit is configured to supply power to the slow start power supply loop;

The discharge circuit is configured to discharge the switch circuit during power down or hot swap.
The circuit of claim 1 wherein said charging circuit comprises: a first diode and a first capacitor, said discharge circuit comprising: a second diode, a second capacitor, a switching transistor, a first MOS transistor And a first resistor; the switch circuit includes: a second loop of the main circuit;

The first capacitor A end is connected to the second MOS transistor gate, the B terminal of the first capacitor is connected to the source of the second MOS transistor, and the first diode A end is respectively The A terminal of the first capacitor is connected to the gate of the second MOS transistor, and the B terminal of the first diode is connected to an external power source and supplies power to the first capacitor and the second MOS transistor;

The B terminal of the second diode is connected to a power source, and the A terminal of the second diode is respectively connected to the A terminal of the second capacitor and the emitter of the switching transistor, and the base of the switching transistor Connected to the A terminal of the first diode, the collector of the switching transistor is connected to the gate of the first MOS transistor, and the source of the first MOS transistor and the B of the second capacitor respectively The terminal is connected to the source of the second MOS transistor, and the drain of the first MOS transistor is respectively connected to the first diode A end and the gate of the second MOS transistor;

The first resistor is connected in parallel with the first capacitor, and is configured to discharge the first capacitor when power is off or hot swap.
The circuit of claim 2, wherein the discharge circuit further comprises: a second resistor;

The second resistor is disposed between the second capacitor and the switching transistor, and is configured to adjust a discharge time of the power supply circuit.
The circuit of claim 2, wherein the discharge circuit further comprises: a third resistor;

The third resistor is disposed between a drain of the first MOS transistor and a base of the switching transistor, and is configured to limit current of the first MOS transistor.
The circuit according to claim 3 or 4, wherein said charging circuit further comprises a voltage dividing circuit, said voltage dividing circuit being arranged to perform voltage division protection on said power supply circuit.
The circuit of claim 5, wherein the voltage dividing circuit comprises: a fourth resistor and a fifth resistor;

One end of the fourth resistor is connected to the power source, and the other end is connected to the B end of the first diode and the second The B end of the diode is connected;

One end of the fifth resistor is connected to the B terminal of the first diode and the B terminal of the second diode, and the other end is connected to the B terminal of the second capacitor, the first MOS transistor, and the The source of the second MOS transistor is connected.
The circuit according to claim 6, wherein said circuit further comprises a protection circuit, one end of which is connected to the power source, and the other end of which is connected to said discharge circuit and said charging circuit, respectively, arranged to regulate said power supply circuit .
The circuit of claim 7 wherein said protection circuit is comprised of a Zener tube;

One end of the Zener diode is connected to a common end of the fourth and the fifth resistors, and the other end is connected to a B terminal of the second capacitor, a source of the first MOS transistor and the second MOS transistor connection.
The circuit of claim 2 wherein said first capacitance and said second capacitance are of the same capacity level.
A circuit according to any one of claims 2 to 9, wherein the switching transistor is a PNP switching transistor.