CN213521671U - Switch power supply single-point grounding control circuit - Google Patents
Switch power supply single-point grounding control circuit Download PDFInfo
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- CN213521671U CN213521671U CN202021833241.1U CN202021833241U CN213521671U CN 213521671 U CN213521671 U CN 213521671U CN 202021833241 U CN202021833241 U CN 202021833241U CN 213521671 U CN213521671 U CN 213521671U
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Abstract
The utility model provides a switching power supply single-point ground connection control circuit, including feedback control unit, main control chip the control unit, switching device unit and transformer and input/output unit, feedback control unit keeps apart through opto-coupler isolation unit with other units, the ground of opto-coupler isolation unit, main control chip the control unit and switching device unit is connected for the single-point with the ground of transformer and input/output unit primary side. The utility model solves the system reliability problem caused by the frequency promotion of the switching device; a new grounding mode is selected, the low-current ground and the high-current ground are connected in a single-point mode, the influence of the high-current ground on the low-current ground is greatly reduced while the electrical property is guaranteed, and the overall reliability and the anti-interference capability of the switching power supply are improved.
Description
Technical Field
The utility model belongs to the technical field of power control, especially, relate to a switching power supply single-point ground connection control circuit.
Background
With the rapid development of devices, the frequency of switching devices is continuously increased, and the frequency of the switching devices in hundreds of KHz, MHz and even GHz has already started to be applied industrially, and with the substantial increase of the frequency of the switching devices, the interference caused by the frequency of the switching devices is also increased, and the influence of electromagnetic interference generated by the switching on and off of the switching devices on the outside or the influence of the outside on the switching power supply is increasingly increased along with the increase of the switching frequency. Therefore, a scheme capable of improving the stability and the anti-interference capability of the switching power supply system is needed to solve the problem of system reliability caused by the frequency rise of the switching device.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the problems and provide a switching power supply single-point grounding control scheme for improving the stability and the anti-interference capability of a switching power supply system,
in order to achieve the above purpose, the utility model adopts the following technical proposal:
a switch power supply single-point grounding control circuit comprises a feedback control unit, a main control chip control unit, a switch device unit, a transformer and an input/output unit, wherein the feedback control unit is isolated from other units through an optical coupling isolation unit, and the grounds of the optical coupling isolation unit, the main control chip control unit and the switch device unit are connected with the ground of the primary side of the transformer and the input/output unit in a single-point mode.
In the single-point ground control circuit of the switching power supply, the secondary sides of the transformer and the input/output unit are provided with multiple isolated output power supplies, and one of the isolated output power supplies is connected to the input end of the feedback control unit and the input end of the input side of the optical coupling isolation unit.
In the single-point ground control circuit of the switching power supply, each isolated output power supply is connected with a rectifier diode for rectifying alternating current to direct current, and a filter capacitor is connected between an output positive end and an output negative end of each isolated output power supply.
In the single-point grounding control circuit of the switching power supply, an electrolytic capacitor for absorbing harmonic waves is connected in series between the positive electrode and the negative electrode of the primary side of the transformer and the input and output unit.
In foretell switching power supply single-point ground control circuit, feedback control unit including two divider resistance of establishing ties between the input and isolation ground, two divider resistance's common port is connected in shunt regulator's input, shunt regulator's A end is connected in isolation ground, shunt regulator's output is connected in optical coupling isolation unit's input side output, and shunt regulator's output passes through feedback resistance and feedback capacitance and connects in shunt regulator's input in order to accomplish feedback control.
In the switching power supply single-point ground control circuit, the optical coupling isolation unit comprises an optical coupling with a light emitting diode and a light sensing triode, the parallel voltage stabilizer is connected to the output end of the light emitting diode, the input end of the light emitting diode is connected to the isolation output power supply through a pull-up resistor, and the input end of the light sensing triode is connected to the reference voltage end of the main control chip control unit through a current limiting resistor.
In the switching power supply single-point grounding control circuit, the main control chip of the main control chip control unit adopts a current type PWM chip, and the COMP end of the main control chip is connected to the common end of the current-limiting resistor and the light sensing triode.
In the switching power supply single-point ground control circuit, the switching device unit includes an MOS transistor, the output terminal of the main control chip control unit is connected to the gate of the MOS transistor through a gate resistor, the drain of the MOS transistor is connected to the transformer and the input/output unit, and the source is connected to the ISENSE terminal of the main control chip control unit through an overcurrent protection resistor.
In the switching power supply single-point grounding control circuit, the grid electrode of the MOS tube is connected to the ground end through a protection resistor and a protection capacitor which are mutually connected in parallel; and the source electrode of the MOS tube is connected to the ground end through a sampling resistor.
In the switching power supply single-point ground control circuit, the secondary side ground of the optical coupling isolation unit, the ground of the main control chip control unit and the ground of the switching device unit are connected into one piece, the primary side ground of the transformer and the input/output unit are connected into the other piece, and the two pieces of ground are connected in a single point.
The utility model has the advantages that: the problem of system reliability caused by frequency improvement of a switching device is solved; a new grounding mode is selected, the low-current ground and the high-current ground are connected in a single-point mode, the influence of the high-current ground on the low-current ground is greatly reduced while the electrical property is guaranteed, and the overall reliability and the anti-interference capability of the switching power supply are improved.
Drawings
Fig. 1 is a schematic circuit diagram of the switching power supply single-point ground control circuit of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the present scheme discloses a switching power supply single-point ground control circuit, which specifically includes a feedback control unit 1, a main control chip control unit 2, a switching device unit 3, a transformer and input/output unit 4, and an optical coupling isolation unit 5. Wherein the ground GND1 of the feedback control unit 1 is isolated, an isolation scheme is adopted with the ground GND of the rest units, and here the feedback control unit 1 is isolated from the rest units by the optical coupling isolation unit 5.
The secondary side ground of the optical coupling isolation unit 5 in each unit, the ground of the main control chip control unit 2, the ground of the switching device unit 3 belong to a low-current ground and are connected into one piece, the primary side ground of the transformer and the input and output unit 4 belong to a high-current ground and are connected into the other piece, and the high-current ground and the low-current ground adopt a single-point connection mode. The single-point connection of the large current ground and the small current ground greatly reduces the influence of the large current ground on the small current ground, and improves the overall reliability and the anti-interference capability of the switching power supply.
Further, the feedback control unit 1 includes two voltage dividing resistors R1 and R2 connected in series between the input terminal connected to the transformer and the output voltage V of the input/output unit 4 and the isolated groundout1One end of the divider resistor R1 is connected to the output voltage Vout1One end of a divider resistor R2 far away from a divider resistor R2 is connected to the ground, the common end of the two divider resistors R1 and R2 is connected to the input end Ref of the shunt regulator TL431B, the A end of the shunt regulator TL431B is connected to the ground, the output end Cath of the shunt regulator TL431B is connected to the input side output end of the optical coupling isolation unit 5, and the output end Cath of the shunt regulator TL431B passes through a feedback resistor R2FAnd a feedback capacitor CFIs connected to the input Ref of the shunt regulator TL431B to complete the feedback control.
Specifically, the optical coupling and isolating unit 5 comprises an optical coupler P817B with a light emitting diode and a phototransistor, wherein the output end Cath of the TL431B is connected with the output end of the light emitting diode, and the input end of the light emitting diode is connected with the output voltage V through a pull-up resistor R3out1The input end of the light sensing triode is connected to the reference voltage end of the main control chip control unit 2 through a current limiting resistor R4, and the output end of the light sensing triode is grounded GND.
Specifically, the main control chip of the main control chip control unit 2 adopts a current type PWM chip UC3844BVD, and the COMP end of the main control chip is connected to the common end of the current limiting resistor R4 and the light sensing triode.
Further, the main control chip passes through RT、CT1、CT2The switching frequency of a chip is set, a VBF end is directly selectively grounded, a VREF end provides reference voltage for light coupling, a GRANG end is directly grounded, a VCC (voltage source converter) is connected with a power supply to provide working voltage for the chip, and an output side OUT is connected with the power supply through a gate resistor RGGrid G connected to MOS tube, ISENSE passing through current protection resistor RIIs connected to the S terminal of the MOSFET,
the drain D of the MOS transistor in the switching device unit 3 is connected to the transformer and input/output unit 4, and the gate G is connected in parallel with the protection resistor RGSAnd a protective capacitor CGCGrounding to protect the MOS tube; the source S of the MOS transistor passes through a sampling resistor RISENSEConnected to ground GND, and real-time sampling current passing through MOS tube via RIThe output voltage is input to the main control chip, once the detected current exceeds the limit value, the main control chip turns off the PWM output to achieve the purpose of MOS tube overcurrent protection.
The secondary side of the transformer and the input/output unit 4 can be based on the systemThe power supply requirement sets up multichannel isolation output power, wherein connect in the input of feedback control unit 1 and the input of 5 input sides of opto-coupler isolation unit all the way. Each path of isolated output power supply rectifies alternating current quantity to direct current quantity through rectifying diodes D1 and D2, and a filter capacitor C is connected between an output positive end and an output negative end of each path of isolated output power supplyout1、Cout22, filtering to meet the ripple requirement of the output voltage; the primary side direct current input selects AC/DC rectification voltage, the voltages at two ends of the direct current side are respectively an anode P and a cathode GND, and RCDs (resistive random access memories, cross-coupled devices, and drive circuits) are used for absorbing induced voltages due to overvoltage damage of MOS (metal oxide semiconductor) tubes caused by voltage impact of the induced voltages of the switching power supply on the MOS tubes.
Further, an electrolytic capacitor C for absorbing harmonic waves is connected in series between the positive electrode P and the negative electrode GND of the primary side of the transformer and input/output unit 4bus1、Cbus2。
In this embodiment, the resistance values of the resistors, the sizes of the capacitors, and the types of the other devices are all selected by those skilled in the art according to the application requirements and the cost budget, and are not limited herein.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims, the invention being directed to direct or indirect connection.
Although the terms feedback control unit 1, optical coupling isolation unit 5, main control chip control unit 2, switching device unit 3, transformer and input-output unit 4, etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed in a manner that is inconsistent with the spirit of the invention.
Claims (10)
1. The switch power supply single-point grounding control circuit is characterized by comprising a feedback control unit (1), a main control chip control unit (2), a switch device unit (3) and a transformer and input and output unit (4), wherein the feedback control unit (1) is isolated from other units through an optical coupling isolation unit (5), and the grounds of the optical coupling isolation unit (5), the main control chip control unit (2) and the switch device unit (3) are connected with the ground of the primary side of the transformer and the input and output unit (4) in a single-point mode.
2. The single-point ground control circuit of the switching power supply according to claim 1, wherein the secondary side of the transformer and the input/output unit (4) has a plurality of isolated output power supplies, and one of the isolated output power supplies is connected to the input end of the feedback control unit (1) and the input end of the input side of the optical coupling isolation unit (5).
3. The single-point ground control circuit of the switching power supply according to claim 2, wherein each of the isolated output power supplies is connected with a rectifying diode for rectifying an alternating current to a direct current, and a filter capacitor is connected between an output positive terminal and an output negative terminal of each of the isolated output power supplies.
4. The single-point ground control circuit of the switching power supply according to claim 3, wherein an electrolytic capacitor for absorbing harmonic waves is connected in series between the positive electrode and the negative electrode of the primary side of the transformer and the input-output unit (4).
5. The switching power supply single-point ground control circuit according to claim 4, wherein the feedback control unit (1) includes two voltage dividing resistors connected in series between the input terminal and the isolated ground, a common terminal of the two voltage dividing resistors is connected to the input terminal of the shunt regulator, the A terminal of the shunt regulator is connected to the isolated ground, the output terminal of the shunt regulator is connected to the input terminal of the optical coupling isolation unit (5), and the output terminal of the shunt regulator is connected to the input terminal of the shunt regulator through the feedback resistor and the feedback capacitor to complete the feedback control.
6. The switching power supply single-point ground control circuit according to claim 5, wherein the optical coupling isolation unit (5) comprises an optical coupler having a light emitting diode and a light sensing triode, the shunt regulator is connected to the output end of the light emitting diode, the input end of the light emitting diode is connected to the isolated output power supply through a pull-up resistor, and the input end of the light sensing triode is connected to the reference voltage end of the main control chip control unit (2) through a current limiting resistor.
7. The switching power supply single-point ground control circuit according to claim 6, wherein a main control chip of the main control chip control unit (2) adopts a current-mode PWM chip, and a COMP end of the main control chip is connected to a common end of the current-limiting resistor and the light sensing triode.
8. The single-point ground control circuit of the switching power supply according to claim 7, wherein the switching device unit (3) comprises a MOS transistor, the output terminal of the main control chip control unit (2) is connected to the gate of the MOS transistor through a gate resistor, the drain of the MOS transistor is connected to the transformer and the input/output unit (4), and the source of the MOS transistor is connected to the ISENSE terminal of the main control chip control unit (2) through an overcurrent protection resistor.
9. The switching power supply single-point ground control circuit according to claim 8, wherein the gate of the MOS transistor is connected to ground through a protection resistor and a protection capacitor connected in parallel; and the source electrode of the MOS tube is connected to the ground end through a sampling resistor.
10. The switching power supply single-point ground control circuit according to claim 9, wherein a secondary side ground of the optical coupling isolation unit (5), a ground of the main control chip control unit (2) and a ground of the switching device unit (3) are connected into one piece, a primary side ground of the transformer and the input/output unit (4) is connected into the other piece, and the two pieces of ground are in single-point connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021833241.1U CN213521671U (en) | 2020-08-28 | 2020-08-28 | Switch power supply single-point grounding control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021833241.1U CN213521671U (en) | 2020-08-28 | 2020-08-28 | Switch power supply single-point grounding control circuit |
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| Publication Number | Publication Date |
|---|---|
| CN213521671U true CN213521671U (en) | 2021-06-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021833241.1U Active CN213521671U (en) | 2020-08-28 | 2020-08-28 | Switch power supply single-point grounding control circuit |
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|---|---|
| CN (1) | CN213521671U (en) |
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- 2020-08-28 CN CN202021833241.1U patent/CN213521671U/en active Active
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