CN114649932A - X capacitor control and start multiplexing circuit, switching power supply controller and switching power supply - Google Patents

X capacitor control and start multiplexing circuit, switching power supply controller and switching power supply Download PDF

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Publication number
CN114649932A
CN114649932A CN202210441151.5A CN202210441151A CN114649932A CN 114649932 A CN114649932 A CN 114649932A CN 202210441151 A CN202210441151 A CN 202210441151A CN 114649932 A CN114649932 A CN 114649932A
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China
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voltage
power supply
vac
circuit
resistor
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Chinese (zh)
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不公告发明人
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Shanghai Canrui Technology Co ltd
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Shanghai Canrui Technology Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/125—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/125—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers
    • H02H7/1252—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for rectifiers responsive to overvoltage in input or output, e.g. by load dump
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/2176—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention relates to an X capacitance control and start multiplexing circuit, a switching power supply controller and a switching power supply, belonging to the field of switching power supplies, wherein the X capacitance control and start multiplexing circuit comprises: the power supply comprises an ultrahigh voltage switch J50, a high voltage switch M50, a voltage dividing unit, a voltage control current device, a diode D50, a reference voltage device, a VAC overvoltage protection unit, a VAC undervoltage protection unit and a VAC open circuit control unit, wherein the constant current charging starting of a power supply port VDD and the starting current closing after the starting are realized through the control of a starting input port VACin, the current backflow of the VDD port is forbidden after the starting of the VDD port is finished, the switching power supply is turned off when the voltage of the VACin is undervoltage at the port, and the starting input port VACin is discharged to the ground when the input of the switching power supply is turned off, so that the safety of user electric equipment is guaranteed, and the efficiency of the user electric equipment is also improved.

Description

X capacitor control and start multiplexing circuit, switching power supply controller and switching power supply
Technical Field
The invention relates to the field of switching power supplies, in particular to an X capacitor control and start multiplexing circuit, a switching power supply controller and a switching power supply.
Background
The power supply is used as a power supply device for all electronic products and needs to meet stricter safety standards and energy efficiency. Because the traditional switching power supply system adopts resistance starting and X capacitor resistance discharging, the current severe standby power consumption requirement is difficult to meet. The standby power consumption of the traditional switching power supply started by adopting the resistor is difficult to reach the standard, the system design is difficult along with the increase of the power, in addition, the X capacitor is generally larger when a high-power supply is designed, and in order to avoid the electric shock to the human body caused by the high-voltage electricity at the power input port when the power supply is powered off, a discharge resistor is generally adopted for processing, so that the great power consumption is brought, the discharge effect is very poor, and the human body is still easily shocked to generate safety accidents.
A conventional switching power converter is illustrated in fig. 1. fig. 1 depicts a conventional power conversion system 10 having operating waveforms illustrated in fig. 2. The voltage in the secondary side coil of the transformer TR is sampled to the FB port of the power converter 11 through a feedback device, and the current in the primary side coil of the transformer is sampled to the CS port of the traditional power converter 11 through the power tube M1 and the current limiting resistor Rcs to generate a square wave signal (Vsw) with variable pulse width to control the on and off of the power tube (M1) so as to complete the transmission of the energy of the transformer. The conventional switching power supply system 10 is started by a resistor, so that the energy efficiency standard of standby power consumption is difficult to fully load, and meanwhile, the resistor is adopted to discharge electricity to the X capacitor when the input is disconnected, so that the power consumption is increased, and an electric shock accident is easily caused to a human body. Therefore, a special technology is needed to control the switching power supply system, so that the situations can be avoided, and the energy efficiency standard can be met, so that the safety and the high efficiency of the electric equipment can be protected.
Disclosure of Invention
The invention aims to provide an X capacitor control and start multiplexing circuit, a switching power supply controller and a switching power supply, which improve the working efficiency and safety of a switching power supply system.
In order to achieve the purpose, the invention provides the following scheme:
an X-capacitance control and start-up multiplexing circuit, the circuit comprising: the device comprises an ultrahigh voltage switch J50, a high voltage switch M50, a voltage division unit, a voltage control current device, a diode D50, a reference voltage device, a VAC overvoltage protection unit, a VAC undervoltage protection unit and a VAC open circuit control unit;
the first input end of the ultrahigh voltage switch J50 and the input end of the voltage division unit are both connected with a starting input port VACin of the circuit, the second input end of the ultrahigh voltage switch J50 is grounded, and the output end of the ultrahigh voltage switch J50 is respectively connected with the drain electrode of the high voltage switch M50 and the input end of the voltage-controlled current device; the source of the high-voltage switch M50 is grounded;
the anode of the diode D50 is connected with the output end of the voltage-controlled current device, and the cathode of the diode D50 is respectively connected with the input end of the reference voltage device and the power supply port VDD of the circuit;
the output end of the reference voltage transformer is respectively connected with the second input end and the voltage reference end of the VAC overvoltage protection unit, the first input end and the voltage reference end of the VAC undervoltage protection unit, and the second input end and the voltage reference end of the VAC open-circuit control unit;
the output end of the voltage division unit is respectively connected with the first input end of the VAC overvoltage protection unit, the second input end of the VAC undervoltage protection unit and the first input end of the VAC open-circuit control unit;
an enable signal end EN of the circuit is respectively connected with an enable end of the voltage-controlled current device, an enable end of the VAC overvoltage protection unit, an enable end of the VAC undervoltage protection unit and an enable end of the VAC open-circuit control unit;
the output end of the VAC overvoltage protection unit is used as a VAC overvoltage protection signal end VACin _ ovp of the circuit; the output end of the VAC undervoltage protection unit is used as a VAC undervoltage protection signal end VACin _ uvp of the circuit; and a VAC open control logic signal output end of the VAC open control unit is connected with the grid of the high-voltage switch M50.
Optionally, the voltage dividing unit includes: a resistor R51 and a resistor R52;
one end of a resistor R51 is connected with a first input end of an extra-high voltage switch J50 and a starting input port VACin of the circuit, the other end of a resistor R51 is connected with one end of a resistor R52, and the other end of a resistor R52 is grounded;
the common point connected between the other end of the resistor R51 and one end of the resistor R52 serves as the output end of the voltage dividing unit.
Optionally, the VAC overvoltage protection unit includes: a first comparator, a first timer and a resistor R53;
the first input end of the first comparator is connected with the output end of the voltage division unit, the second input end of the first comparator is connected with one end of a resistor R53, and the other end of the resistor R53 is connected with the output end of the reference voltage device; the output end of the first comparator is connected with the input end of the first timer; a first voltage input end of the first comparator is connected with an output end of the reference voltage device, and a second voltage input end of the first comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the first timer is connected with the output end of the reference voltage device, the enabling end of the first timer is connected with the enabling signal end EN of the circuit, and the output end of the first timer is used as a VAC overvoltage protection signal end VACin _ ovp of the circuit.
Optionally, the VAC undervoltage protection unit includes: a second comparator, a second timer, and a resistor R54;
a first input end of the second comparator is connected with one end of a resistor R54, and the other end of the resistor R54 is connected with one end of a resistor R53; the second input end of the second comparator is connected with the output end of the voltage division unit; the output end of the second comparator is connected with the input end of the second timer; a first voltage input end of the second comparator is connected with an output end of the reference voltage device, and a second voltage input end of the second comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the second timer is connected with the output end of the reference voltage, the enable end of the second timer is connected with the enable signal end EN of the circuit, and the output end of the second timer is used as a VAC undervoltage protection signal end VACin _ uvp of the circuit.
Optionally, the VAC open circuit control unit includes: a third comparator, a third timer, a resistor R55, and a resistor R56;
a first input end of the third comparator is connected with an output end of the voltage division unit, a second input end of the third comparator is respectively connected with one end of a resistor R55 and one end of a resistor R56, the other end of the resistor R55 is connected with one end of a resistor R54, and the other end of the resistor R56 is grounded; the output end of the third comparator is connected with the input end of the third timer; a first voltage input end of the third comparator is connected with an output end of the reference voltage device, and a second voltage input end of the third comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the third timer is connected with the output end of the reference voltage device, the enabling end of the third timer is connected with the enabling signal end EN of the circuit, and the output end of the third timer is connected with the grid electrode of the high-voltage switch M50.
Optionally, the circuit further includes: a resistor R50;
one end of the resistor R50 is connected with the output end of the extra-high voltage switch J50 and the input end of the voltage-controlled current device, and the other end of the resistor R50 is connected with the drain electrode of the high-voltage switch M50.
A switching power supply controller, the controller comprising: the power-on/power-off enabling circuit UVLO, the pulse width modulator PWM, the driving circuit DRIVER and the X capacitor control and start multiplexing circuit are arranged;
the input end of the drive circuit DRIVER is respectively connected with a power supply port VDD of the X capacitor control and start multiplexing circuit, a VAC overvoltage protection signal end VACin _ ovp, a VAC undervoltage protection signal end VACin _ uvp, the input end of the up-down power enable circuit UVLO and the output end of the pulse width modulator PWM; the output end of the driving circuit DRIVER is used as the switching signal output end of the controller;
the output end of the up-down power enable circuit UVLO is connected with an enable signal end EN of the X capacitance control and start multiplexing circuit;
the input end of the power-on/power-off enabling circuit UVLO is used as a power supply port of the controller; the starting input port VACin of the X capacitance control and starting multiplexing circuit is used as the starting input port VACin of the controller, the first input end of the pulse width modulator PWM is used as the feedback port of the controller, the second input end of the pulse width modulator PWM is used as the current monitoring port of the controller, and the ground port of the controller is grounded.
A switching power supply, comprising: the transformer TR, the power switch tube M1, the feedback device and the switch power supply controller;
one end of a primary coil of the transformer TR is connected with the drain electrode of the power tube M1, and the other end of the primary coil of the transformer TR is used as the voltage input end of the switching power supply; one end of a secondary coil of the transformer TR is connected with one end of the feedback device; two ends of a secondary side coil of the transformer TR are used as direct-current voltage output ends of the switching power supply;
the grid electrode of the power tube M1 is connected with the switching signal output end of the switching power supply controller, and the source electrode of the power tube M1 is connected with the current monitoring port of the switching power supply controller;
the other end of the feedback device is connected with a feedback port of the switching power supply controller.
Optionally, the switching power supply further includes: a capacitor Cx, a full-wave rectifier diode Dx1, a full-wave rectifier diode Dx2, a full-wave rectifier diode D1, and a capacitor C1;
the two ends of the capacitor Cx are respectively connected with the two ends of the input line voltage; an anode of the full-wave rectifier diode Dx1 is connected to one end of the capacitor Cx and the first end of the full-wave rectifier diode D1, respectively; the cathode of the full-wave rectifying diode Dx1 is respectively connected with the cathode of the full-wave rectifying diode Dx2 and the starting input port VACin of the switching power supply controller; the anode of the full-wave rectifying diode Dx2 is connected to the other end of the capacitor Cx and the second end of the full-wave rectifying diode D1, respectively;
the third end of the full-wave rectifying diode D1 is connected with one end of the capacitor C1 and then grounded, and the fourth end of the full-wave rectifying diode D1 is respectively connected with the other end of the capacitor C1 and the other end of the primary coil of the transformer TR.
Optionally, the switching power supply further includes: resistor R1, diode D2, and capacitor CVDDAnd an auxiliary coil La;
one end of the resistor R1 is connected to the capacitor CVDDOne end of the resistor R1 is connected with the power supply port of the switch power supply controller, and the other end of the resistor R1 is connected with the cathode of the diode D2; capacitor CVDDThe other end of the first and second electrodes is grounded;
one end of the auxiliary coil La is connected to the anode of the diode D2, and the other end of the auxiliary coil La is grounded.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention discloses an X capacitor control and start multiplexing circuit, a switch power supply controller and a switch power supply, wherein the X capacitor control and start multiplexing circuit responds to a start input port VACin and an enable signal end EN to respectively generate an overvoltage protection enable signal at a VAC overvoltage protection signal end VACin _ ovp, generates an undervoltage protection enable signal at a VAC undervoltage protection signal end VACin _ uvp, responds to the enable signal end EN and a power supply port VDD to generate protection enable signals at a VAC overvoltage protection signal end VACin _ ovp and a VAC undervoltage protection signal end VACin _ uvp, and inputs a VAC power supply controller with overhigh voltage or overlow voltage to avoid damaging the switch power supply at the system, and a diode D50 can avoid the current backflow action of the power supply port VDD and improve the working safety of a switch power supply system; and further, when the input of the VAC port is disconnected, the input port VACin is started to quickly discharge to zero to the ground, so that the safety of the X capacitor to a human body is ensured. Namely, the invention realizes the constant-current charging starting of the power supply port VDD and the starting current closing after the starting is finished, realizes the purpose of prohibiting the current of the VDD port from flowing backwards after the port VDD is started, realizes the purpose of closing the switch power supply when the port VACin is under-voltage and overvoltage, and realizes the purpose of discharging the starting input port VACin to the ground when the input of the switch power supply is disconnected by controlling the starting input port VACin, thereby ensuring the safety of the user electric equipment and improving the efficiency of the user electric equipment.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a conventional switching power converter;
FIG. 2 is a waveform diagram illustrating operation of a conventional switching power converter;
FIG. 3 is a block diagram of an X capacitor control and start-up multiplexing circuit according to the present invention;
fig. 4 is a structural diagram of a switching power supply provided by the present invention;
FIG. 5 is a diagram showing a comparison of waveforms of system start-up timing sequences of the switching power supply of the present invention and the conventional switching power supply after the input line voltage VAC;
FIG. 6 is a timing waveform comparison diagram of the voltage of the X capacitor when the AC input line voltage VAC is disconnected between the switching power supply of the present invention and the conventional switching power supply;
fig. 7 is a comparison diagram of waveforms of the switching power supply of the present invention and the conventional switching power supply when the ac input line voltage VAC is over-voltage or under-voltage.
Description of the symbols: the power supply comprises a 10-traditional switching power supply, a 11-traditional power supply converter, a 12-feedback device, a 20-power-up and power-down enabling circuit, a 30-pulse width modulator, a 40-driving circuit, a 50-X capacitance control and starting multiplexing circuit, a 51-voltage control current device, a 52-reference voltage device, a 53-first timer, a 54-third timer, a 55-second timer, a 56-third comparator, a 57-second comparator, a 58-first comparator, a 10A-switching power supply and a 11A-switching power supply controller.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide an X capacitor control and start multiplexing circuit, a switching power supply controller and a switching power supply, which improve the working efficiency and safety of a switching power supply system.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Example 1
An embodiment of the present invention provides an X capacitor control and start multiplexing circuit 50, as shown in fig. 3, including: the device comprises an ultrahigh voltage switch J50, a high voltage switch M50, a voltage division unit, a voltage-controlled current device 51, a diode D50, a reference voltage device 52, a VAC overvoltage protection unit, a VAC undervoltage protection unit and a VAC open circuit control unit.
The first input end of the extra-high voltage switch J50 and the input end of the voltage division unit are both connected with a starting input port VACin of the circuit, the second input end of the extra-high voltage switch J50 is grounded, and the output end of the extra-high voltage switch J50 is respectively connected with the drain electrode of the high voltage switch M50 and the input end of the voltage-controlled current controller 51; the source of the high voltage switch M50 is connected to ground. The anode of the diode D50 is connected to the output terminal of the voltage-controlled current device 51, and the cathode of the diode D50 is connected to the input terminal of the reference voltage device 52 and the power supply port VDD of the circuit. The output end of the reference voltage transformer 52 is respectively connected with the second input end and the voltage reference end of the VAC overvoltage protection unit, the first input end and the voltage reference end of the VAC undervoltage protection unit, and the second input end and the voltage reference end of the VAC open-circuit control unit. The output end of the voltage division unit is respectively connected with the first input end of the VAC overvoltage protection unit, the second input end of the VAC undervoltage protection unit and the first input end of the VAC open-circuit control unit. The enable signal terminal EN of the circuit is respectively connected with the enable terminal of the voltage-controlled current device 51, the enable terminal of the VAC overvoltage protection unit, the enable terminal of the VAC undervoltage protection unit and the enable terminal of the VAC open-circuit control unit. The output end of the VAC overvoltage protection unit is used as a VAC overvoltage protection signal end VACin _ ovp of the circuit; the output end of the VAC undervoltage protection unit is used as a VAC undervoltage protection signal end VACin _ uvp of the circuit; and a VAC open control logic signal output end of the VAC open control unit is connected with the grid of the high-voltage switch M50.
The input VACin of the extra-high voltage switch J50 is 90-264VAC, and the output end is slightly higher than VDDThe voltage of (c). When the input EN voltage signal of the voltage-controlled current device 51 is logic "0", the output maximum value is ICH0I of (A)CH_VDDWhen the input EN voltage signal is a logic "1", the output current is 0, and the voltage-controlled current controller 51 is turned off.
The X capacitor control and start multiplexing circuit 50 performs constant current start on the power supply port VDD after responding to the enable signal terminal EN thereof to draw current at the start input port VACin. The X-capacitor control and enable multiplexing circuit 50 generates a protection enable signal at the VAC overvoltage protection signal terminal VACin _ ovp in response to the enable input port VACin and the enable signal terminal EN. The X-capacitor control and start-up multiplexing circuit 50 generates a protection enable signal at the VAC undervoltage protection signal terminal VACin _ uvp in response to the start-up input port VACin and the enable signal terminal EN. The X capacitor control and start multiplexing circuit 50 responds to an enable signal end EN and a power supply port VDD to generate an overvoltage protection enable signal at a VAC overvoltage protection signal end VACin _ ovp, a VAC undervoltage protection signal end VACin _ uvp generates an undervoltage protection enable signal, and the switching power supply controller 11A is turned off when the input VAC voltage of the system is too high or too low, so that the switching power supply system is prevented from being damaged, and a better safety effect is achieved. The X capacitor control and start multiplexing circuit 50 responds to the enable signal terminal EN, and closes the charge current of the start input port VACin to the power port VDD after the power port VDD is started, so as to achieve the effect of saving the system power consumption. The internal device D50 of the X capacitor control and start-up multiplexing circuit 50 can prevent the current from flowing backward through the power supply port VDD of the X capacitor control and start-up multiplexing circuit 50. The temperature drift of the charging current of the X capacitor control and start multiplexing circuit 50 to the power supply port VDD approaches zero. The X capacitor control and start multiplexing circuit 50 responds to the start input port VACin, and when the input of the VAC port is disconnected, the start input port VACin is enabled to discharge to zero quickly to ground, so as to ensure the safety of the X capacitor to human body.
The voltage class of 110kV to 220kV is called high voltage. The voltage class of 330kV to 500kV is called ultra-high voltage.
Illustratively, the voltage dividing unit includes: resistor R51 and resistor R52. One end of the resistor R51 is connected with a first input end of the extra-high voltage switch J50 and a starting input port VACin of the circuit, the other end of the resistor R51 is connected with one end of the resistor R52, and the other end of the resistor R52 is grounded. The other end of the resistor R51 and one end of the resistor R52 are connected with a common point as an output end of the voltage division unit.
Illustratively, the VAC overvoltage protection unit includes: first comparator 58, first timer 53, and resistor R53. A first input end of the first comparator 58 is connected with the output end of the voltage dividing unit, a second input end of the first comparator 58 is connected with one end of the resistor R53, and the other end of the resistor R53 is connected with the output end of the reference voltage device 52; the output of the first comparator 58 is connected to the input of the first timer 53; a first voltage input of the first comparator 58 is connected to the output of the reference voltage transformer 52, and a second voltage input of the first comparator 58 is connected to an enable signal terminal EN of the circuit. The voltage reference terminal of the first timer 53 is connected to the output terminal of the reference voltage transformer 52, the enable terminal of the first timer 53 is connected to the enable signal terminal EN of the circuit, and the output terminal of the first timer 53 serves as the VAC overvoltage protection signal terminal VACin _ ovp of the circuit.
Illustratively, the VAC undervoltage protection unit includes: a second comparator 57, a second timer 55 and a resistor R54. A first input end of the second comparator 57 is connected with one end of the resistor R54, and the other end of the resistor R54 is connected with one end of the resistor R53; a second input end of the second comparator 57 is connected with the output end of the voltage division unit; the output of the second comparator 57 is connected to the input of the second timer 55; a first voltage input of the second comparator 57 is connected to the output of the reference voltage transformer 52, and a second voltage input of the second comparator 57 is connected to the enable signal terminal EN of the circuit. The voltage reference terminal of the second timer 55 is connected to the output terminal of the reference voltage 52, the enable terminal of the second timer 55 is connected to the enable signal terminal EN of the circuit, and the output terminal of the second timer 55 serves as the VAC undervoltage protection signal terminal VACin _ uvp of the circuit.
Illustratively, the VAC open circuit control unit includes: a third comparator 56, a third timer 54, a resistor R55, and a resistor R56. A first input end of the third comparator 56 is connected with the output end of the voltage dividing unit, a second input end of the third comparator 56 is respectively connected with one end of a resistor R55 and one end of a resistor R56, the other end of the resistor R55 is connected with one end of a resistor R54, and the other end of the resistor R56 is grounded; the output of the third comparator 56 is connected to the input of the third timer 54; a first voltage input of the third comparator 56 is connected to the output of the reference voltage transformer 52, and a second voltage input of the third comparator 56 is connected to the enable signal terminal EN of the circuit. The voltage reference terminal of the third timer 54 is connected to the output terminal of the reference voltage 52, the enable terminal of the third timer 54 is connected to the enable signal terminal EN of the circuit, and the output terminal of the third timer 54 is connected to the gate of the high voltage switch M50.
The first timer 53, the second timer 55 and the third timer 54 have logic low inputs and logic low outputs, and have logic high inputs for keeping counting for the timing times T1, T2 and T3, and the outputs are turned to logic high. The output terminals of the first comparator 58, the second comparator 57, and the third comparator 56 are in the same phase with the positive terminal, i.e., the output is logic high when the voltage of the positive terminal is higher than that of the negative terminal, and is logic low otherwise.
Illustratively, the circuit further comprises: a resistor R50. One end of the resistor R50 is connected to the output end of the extra-high voltage switch J50 and the input end of the voltage-controlled current device 51, and the other end of the resistor R50 is connected to the drain of the high voltage switch M50.
In FIG. 3, VACin: starting input voltage, VACin 1: partial pressure of VACin, IJ: conduction current of J50, Idischarge: discharge current, VJS: output terminal voltage of J50, VACin _ open: control logic signal of open VAC circuit, ICH_VDD: charging current, V, of switching power supply 10ADD: power port voltage, VREF: reference voltage transformer 52, TIMER 1: first TIMER 53, TIMER 2: second TIMER 55, TIMER 3: third timer 54, C1: first comparator 58, C2: second comparator 57, C3: third comparator 56, vref: output terminal voltage of reference voltage 52(VREF), VREF 1: reference voltage 1, vref 2: reference voltage 2, vref 3: reference voltage 3, ovp — en: overvoltage protection enable signal, uvp _ en: undervoltage protection enable signal, open _ en: an open enable signal.
The circuit for controlling the X capacitor and starting multiplexing can be applied to a switching power supply and the like, and the switching power supply system containing the circuit can work more safely and efficiently by controlling the input port VACin in the circuit.
Example 2
A switching power supply controller 11A, as shown in fig. 4, includes: the power-up and power-down enabling circuit UVLO20, the pulse width modulator PWM30, the driving circuit DRIVER40, and the aforementioned X capacitance control and start multiplexing circuit 50.
The input end of the DRIVER40 is respectively connected with the power supply port VDD of the X capacitor control and start multiplexing circuit 50, the VAC overvoltage protection signal end VACin _ ovp, the VAC undervoltage protection signal end VACin _ uvp, the input end of the up-down power enable circuit UVLO20, and the output end of the pulse width modulator PWM 30; the output terminal of the DRIVER40 serves as the switching signal output terminal of the controller. The output terminal of the power-up and power-down enabling circuit UVLO20 is connected to the enable signal terminal EN of the X capacitor control and enable multiplexing circuit 50. An input end of an up-down enabling circuit UVLO20 is used as a power supply port of the controller; the starting input port VACin of the X capacitance control and starting multiplexing circuit 50 serves as the starting input port VACin of the controller, the first input end of the pulse width modulator PWM30 serves as the feedback port of the controller, the second input end of the pulse width modulator PWM30 serves as the current monitoring port of the controller, and the ground port of the controller is grounded.
The switching power supply controller 11A may be applied to a transformer secondary side feedback isolation type and a transformer primary side feedback isolation type switching power supply system. The driving circuit switching power supply controller 11A is embedded in an integrated circuit by a circuit of multiplexing control and start of an X capacitor, a power-up and power-down enabling circuit 20, a pulse width modulator 30 and a driving circuit 40, so as to save external devices.
In FIG. 4, VPWM: pulse width comparator output signal, Vsw: switching signal, VDD: power port, VACin: start input port, FB: feedback port, CS: current monitoring port, DRV: drive output port, GND: and a ground port.
Example 3
A switching power supply 10A, as shown in fig. 4, the switching power supply 10A includes: the transformer TR, the power switch tube M1, the feedback device 12 and the aforementioned driving circuit switch the power supply controller 11A.
One end of a primary coil of the transformer TR is connected with the drain electrode of the power tube M1, and the other end of the primary coil of the transformer TR is used as the voltage input end of the switching power supply 10A; one end of the secondary winding of the transformer TR is connected to one end of the feedback 12; two ends of the secondary coil of the transformer TR serve as dc voltage output terminals of the switching power supply 10A. The gate of the power transistor M1 is connected to the switching signal output terminal of the driving circuit switching power supply controller 11A, and the source of the power transistor M1 is connected to the current monitoring port of the driving circuit switching power supply controller 11A. The other end of the feedback 12 is connected to a feedback port of the driving circuit switching power supply controller 11A.
The X-capacitor control and start-up multiplexing circuit 50 is embedded in an integrated circuit of the driving circuit switching power supply controller 11A.
The driving circuit switching power supply controller 11A is coupled to a feedback device 12 disposed at the output terminal of the transformer TR to generate a switching signal VSWSwitching signal VSWThe pulse width of the transformer TR is adjusted through the power switch, so that the energy transmission of the switching power supply 10A comprising the circuit is regulated and controlled; the driving circuit switching power supply controller 11A is formed by coupling an X capacitor control and start multiplexing circuit 50, a power up/down enabling circuit 20, a pulse width modulator 30 and a driving circuit 40.
The user can start the switching power supply 10A containing the constant current power supply system through the starting input port VACin, the starting path can be automatically cut off after the power supply system is started, energy consumption is saved, and safety and high efficiency of user electric equipment are guaranteed to the maximum extent; the X capacitor control and start multiplexing circuit 50 responds to the start input port VACin, and triggers a protection action to turn off the switching power supply 10A including the present invention when the voltage at the port is too high or too low, thereby ensuring the safety of the switching power supply 10A employing the present invention; the X-capacitor control and start multiplexing circuit 50 responds to the start input port VACin, and when the input VAC of the switching power supply 10A including the present invention is turned off, the start input port VACin is rapidly discharged to the ground, thereby ensuring the electrical safety of the switching power supply 10A employing the present invention to the human body.
Illustratively, the switching power supply 10A further includes: capacitor Cx, full-wave rectifier diode Dx1, full-wave rectifier diode Dx2, full-wave rectifier diode D1, and capacitor C1. The two ends of the capacitor Cx are respectively connected with the two ends of the input line voltage; an anode of the full-wave rectifying diode Dx1 is connected to one end of the capacitor Cx and a first end of the full-wave rectifying diode D1, respectively; the cathode of the full-wave rectifying diode Dx1 is respectively connected with the cathode of the full-wave rectifying diode Dx2 and the start input port VACin of the drive circuit switching power controller 11A; the anode of the full-wave rectifying diode Dx2 is connected to the other end of the capacitor Cx and the second end of the full-wave rectifying diode D1. The third end of the full-wave rectifying diode D1 is connected with one end of the capacitor C1 and then grounded, and the fourth end of the full-wave rectifying diode D1 is respectively connected with the other end of the capacitor C1 and the other end of the primary coil of the transformer TR.
Illustratively, the switching power supply 10A further includes: resistor R1, diode D2, and capacitor CVDDAnd an auxiliary coil La. One end of the resistor R1 is connected to the capacitor CVDDOne end of the resistor R1 is connected with the power port of the driving circuit switch power controller 11A, and the other end of the resistor R1 is connected with the cathode of the diode D2; capacitor CVDDAnd the other end of the same is grounded. One end of the auxiliary coil La is connected to the anode of the diode D2, and the other end of the auxiliary coil La is grounded.
In fig. 4, VAC: input line voltage, Vo: direct-current output voltage of the switching power supply, Lp: primary coil of transformer TR, Ls: secondary winding of transformer TR, La: an auxiliary coil of the transformer TR, an auxiliary coil La is responsible for providing a capacitor C of a VDD portVDDPower supply, D3: diode, C2: capacitor, Ics: primary winding current, V, of transformer TRFB: feedback voltage, Vcs: the current is monitored.
Referring to fig. 4, one end of the secondary winding of the transformer TR is connected to the anode of the diode D3, one end of the capacitor C2 is connected to the cathode of the diode D3, and the other end of the capacitor C2 is connected to the other end of the secondary winding of the transformer TR.
Illustratively, the switching power supply 10A further includes: a resistance Rcs. One end of the resistor Rcs is connected with the source electrode of the power tube M1, and the other end of the resistor Rcs is grounded.
The invention can realize the constant-current charging starting of the power supply port VDD and the closing of the starting current after the starting is finished, the prohibition of the backward flow of the current of the VDD port after the starting of the port VDD is finished, the closing of the switch power supply 10A comprising the invention when the voltage of the port VACin is undervoltage and overvoltage, and the discharge of the port VACin to the ground when the input of the switch power supply 10A comprising the invention is disconnected, thereby not only ensuring the safety of the user electric equipment, but also improving the efficiency of the user electric equipment, and having higher market application prospect.
The operation waveforms of the X-capacitor control and start multiplexing circuit 50 of the present invention are shown in fig. 5, 6 and 7, and the operation principle is as follows:
during the charging process of VDD from 0, when VDD<VDDONTime (VDD)ONPower-up threshold), EN is logic "0", controlling the voltage-controlled current device 51 to output a current ICH_VDDCharging the VDD port, I in the starting processCH_VDDThe temperature is ultra-low. EN is a logic "0" setting a "0" to the output of all comparators and timers. VACin _ open is a logic "0" and controls M50 to open.
In the process of charging and powering up the VDD from 0, when the VDD is charged>VDDONWhen EN is logic "1", turn off the voltage-controlled current 51, and start-up charging current I at VDD portCH_VDDThe power consumption of the current for starting charging is saved to be 0, at the moment, the starting of the VDD port is finished, and the whole circuit enters normal operation. VDD is higher than VDD after startupONAnd the voltage is much higher than the anode voltage of D50, the D50 reversely isolates the VDD port, and the phenomena of power loss, starting failure and the like caused by the backward current of the VDD port to the circuit 50 are avoided.
VTHN is the turn-on threshold of the high-voltage switch, R51, R52 are matched super resistors with proportionality coefficient beta (0< beta <1), R53, R54, R55, R56 are matched precise resistors with proportionality coefficients theta 1, theta 2, theta 3 (0< theta 3< theta 2< theta 1),
R52＝β(R51+R52) (1)
R56＝θ3(R53+R54+R55+R56) (2)
R55+R56＝θ2(R53+R54+R55+R56) (3)
R54+R55+R56＝θ1(R53+R54+R55+R56) (4)
the reference voltage 52 responds to the port VDD to generate a reference voltage vref, the reference voltages vref1, vref2 and vref3 are obtained through voltage division of resistors R53-R56,
vref1＝θ1×vref (5)
vref2＝θ2×vref (6)
vref3＝θ3×vref (7)
VACin1＝β×VACin (8)
therefore, when the switching power supply system of the present invention inputs VAC overvoltage,
VACin1＝β×VACin>vref1＝θ1×vref (9)
after the output ovp _ en of the first comparator 58 is logic "1", the first timer 53 starts counting, and if the duration reaches the time T1, the output VACin _ ovp of the first timer 53 is logic "1", the driving circuit of the present invention is turned off, and the switching power supply controller 11A is turned on, so as to avoid the damage caused by the input overvoltage of the system 10A.
If when the switching power supply system of the present invention inputs VAC undervoltage,
VACin1＝β×VACin<vref2＝θ2×vref (10)
uvp _ en output by the second comparator 57 is logic "1", the second timer 55 starts counting, and if the duration reaches time T2, the output of the second timer 55 is logic "1", the driving circuit switching power supply controller 11A of the present invention is turned off, thereby avoiding the damage caused by the input under-voltage of the system 10A.
When the switching power supply system of the present invention is turned off by the input VAC, if:
VACin1＝β×VACin>vref3＝θ3×vref (11)
that is, VACin > Vxcap _ disch ═ θ 3 × vref/β (12)
Here, Vxcap _ disch _ th <36V is a VACin voltage threshold value of the discharge of the X capacitor, and the output open _ en is logic "1" through the third comparator 56, the third timer 54 starts counting, and if the duration reaches time T3, the third timer 54 outputs VACin _ open is logic "1", and the M50 is controlled to be turned on, so that the VACin port is discharged to the ground through M50, R50, and J50. As a result, the switching power supply 10A of the invention can complete the discharge of the X capacitor to the ground within the time T4 (T4< <0.3s) when the input is powered off, thereby avoiding the human body electric shock accident caused by the power off of the system 10A.
The switching power supply 10A incorporating the present invention achieves both safety, wide temperature operating consistency, and minimization of standby power consumption.
Fig. 5 shows a comparison of the system startup timing waveforms of the switching power supply 10A according to the present invention and the conventional switching power supply 10 after the input line voltage VAC. As can be seen from the waveforms in fig. 5, the switching power supply 10A of the present invention rapidly increases VDD to VDD after VAC is inputONAfter that, the starting current is turned off, the starting current ICH_VDDIs 0, power loss is saved; whereas the conventional switching power supply 10 system has VDD rising VDD after VAC inputONThen, the starting current cannot be turned off, and fixed power consumption occurs in the starting resistor.
Fig. 6 is a comparison of the waveforms of the voltages of the X capacitor when the ac input line voltage VAC is off between the switching power supply 10A of the present invention and the conventional switching power supply 10. As can be seen from the waveforms in fig. 6, the switching power supply 10A of the present invention discharges the voltage VACin of the X capacitor to ground within a very short time T4 after the time T3 is reached after the system input VAC is turned off by the detection of the third timer 54, whereas the high voltage (far exceeding the human body voltage of 36V) that the conventional switching power supply 10 continues after the system input VAC is turned off can shock the human body at the input port of the system when the human body touches it, causing an accident.
Fig. 7 is a waveform comparison of the switching power supply 10A according to the present invention and the conventional switching power supply 10 when the ac input line voltage VAC is over-voltage or under-voltage. As can be seen from the waveforms in fig. 7, when the switching power supply 10A of the present invention continues to generate the system input VAC undervoltage for the timing time T2 of the second timer 55, the signal VACin _ uvp is logic "1" to turn off the driving output Vsw of the system to enter the automatic restart protection mode at the VDD terminal, so as to protect the switching power supply 10A; when the overvoltage of the system input VAC of the switching power supply 10A of the present invention continuously occurs for the timing time T1 of the timer 53, the signal VACin _ ovp is a logic "1" to turn off the driving output Vsw of the system to enter the automatic restart protection mode of VDD, thereby protecting the switching power supply 10A. After the protection is released, the system will resume normal operation after the next automatic restart of VDD. Based on the conventional switching power supply system 10, it can be seen from the waveform that the driving signal Vsw of the system works normally regardless of the overvoltage or undervoltage of the input VAC of the system, so that if the VAC voltage is too high, and the power tube M1 is turned off during the switching action, the drain of the power tube M1 is damaged due to too high drain voltage caused by flyback, and if the VAC is too low, the explosion accident due to transformer saturation may occur.
In fig. 1, Rst: starting resistor of switching power supply system, IST: the charging current of the power supply system is switched on and off. In FIG. 2, VFB: and feeding back the voltage.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims (10)

1. An X-capacitor control and start-up multiplexing circuit, the circuit comprising: the device comprises an ultrahigh voltage switch J50, a high voltage switch M50, a voltage division unit, a voltage control current device, a diode D50, a reference voltage device, a VAC overvoltage protection unit, a VAC undervoltage protection unit and a VAC open circuit control unit;
the first input end of the ultrahigh voltage switch J50 and the input end of the voltage division unit are both connected with a starting input port VACin of the circuit, the second input end of the ultrahigh voltage switch J50 is grounded, and the output end of the ultrahigh voltage switch J50 is respectively connected with the drain electrode of the high voltage switch M50 and the input end of the voltage-controlled current device; the source of the high-voltage switch M50 is grounded;
the anode of the diode D50 is connected with the output end of the voltage-controlled current device, and the cathode of the diode D50 is respectively connected with the input end of the reference voltage device and the power supply port VDD of the circuit;
the output end of the reference voltage transformer is respectively connected with the second input end and the voltage reference end of the VAC overvoltage protection unit, the first input end and the voltage reference end of the VAC undervoltage protection unit, and the second input end and the voltage reference end of the VAC open-circuit control unit;
the output end of the voltage division unit is respectively connected with the first input end of the VAC overvoltage protection unit, the second input end of the VAC undervoltage protection unit and the first input end of the VAC open-circuit control unit;
an enable signal end EN of the circuit is respectively connected with an enable end of the voltage-controlled current device, an enable end of the VAC overvoltage protection unit, an enable end of the VAC undervoltage protection unit and an enable end of the VAC open-circuit control unit;
the output end of the VAC overvoltage protection unit is used as a VAC overvoltage protection signal end VACin _ ovp of the circuit; the output end of the VAC undervoltage protection unit is used as a VAC undervoltage protection signal end VACin _ uvp of the circuit; and a VAC open control logic signal output end of the VAC open control unit is connected with the grid of the high-voltage switch M50.
2. The X-capacitance control and start-up multiplexing circuit of claim 1 wherein the voltage divider unit comprises: a resistor R51 and a resistor R52;
one end of a resistor R51 is connected with a first input end of an extra-high voltage switch J50 and a starting input port VACin of the circuit, the other end of a resistor R51 is connected with one end of a resistor R52, and the other end of a resistor R52 is grounded;
the other end of the resistor R51 and one end of the resistor R52 are connected with a common point as an output end of the voltage division unit.
3. The X capacitance control and start-up multiplexing circuit of claim 1 wherein said VAC overvoltage protection unit comprises: a first comparator, a first timer and a resistor R53;
the first input end of the first comparator is connected with the output end of the voltage division unit, the second input end of the first comparator is connected with one end of a resistor R53, and the other end of the resistor R53 is connected with the output end of the reference voltage device; the output end of the first comparator is connected with the input end of the first timer; a first voltage input end of the first comparator is connected with an output end of the reference voltage device, and a second voltage input end of the first comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the first timer is connected with the output end of the reference voltage, the enabling end of the first timer is connected with the enabling signal end EN of the circuit, and the output end of the first timer is used as a VAC overvoltage protection signal end VACin _ ovp of the circuit.
4. The X capacitance control and start-up multiplexing circuit of claim 3 wherein the VAC undervoltage protection unit comprises: a second comparator, a second timer, and a resistor R54;
a first input end of the second comparator is connected with one end of a resistor R54, and the other end of the resistor R54 is connected with one end of a resistor R53; the second input end of the second comparator is connected with the output end of the voltage division unit; the output end of the second comparator is connected with the input end of the second timer; a first voltage input end of the second comparator is connected with an output end of the reference voltage device, and a second voltage input end of the second comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the second timer is connected with the output end of the reference voltage, the enable end of the second timer is connected with the enable signal end EN of the circuit, and the output end of the second timer is used as a VAC undervoltage protection signal end VACin _ uvp of the circuit.
5. The X capacitance control and start-up multiplexing circuit of claim 4 wherein the VAC open control unit comprises: a third comparator, a third timer, a resistor R55, and a resistor R56;
a first input end of the third comparator is connected with an output end of the voltage dividing unit, a second input end of the third comparator is respectively connected with one end of a resistor R55 and one end of a resistor R56, the other end of the resistor R55 is connected with one end of a resistor R54, and the other end of the resistor R56 is grounded; the output end of the third comparator is connected with the input end of the third timer; a first voltage input end of the third comparator is connected with an output end of the reference voltage device, and a second voltage input end of the third comparator is connected with an enable signal end EN of the circuit;
the voltage reference end of the third timer is connected with the output end of the reference voltage device, the enabling end of the third timer is connected with the enabling signal end EN of the circuit, and the output end of the third timer is connected with the grid electrode of the high-voltage switch M50.
6. The X-capacitance control and start multiplexing circuit of claim 1, further comprising: a resistor R50;
one end of the resistor R50 is connected with the output end of the extra-high voltage switch J50 and the input end of the voltage-controlled current device, and the other end of the resistor R50 is connected with the drain electrode of the high-voltage switch M50.
7. A switching power supply controller, characterized in that the controller comprises: the power-on and power-off enabling circuit UVLO, the pulse width modulator PWM, the driving circuit DRIVER and the X capacitance control and starting multiplexing circuit of any one of claims 1-6;
the input end of the drive circuit DRIVER is respectively connected with a power supply port VDD of the X capacitor control and start multiplexing circuit, a VAC overvoltage protection signal end VACin _ ovp, a VAC undervoltage protection signal end VACin _ uvp, the input end of the up-down power enable circuit UVLO and the output end of the pulse width modulator PWM; the output end of the drive circuit DRIVER is used as the switching signal output end of the controller;
the output end of the up-down power enable circuit UVLO is connected with an enable signal end EN of the X capacitance control and start multiplexing circuit;
the input end of the power-on/power-off enabling circuit UVLO is used as a power supply port of the controller; the starting input port VACin of the X capacitance control and starting multiplexing circuit is used as the starting input port VACin of the controller, the first input end of the pulse width modulator PWM is used as the feedback port of the controller, the second input end of the pulse width modulator PWM is used as the current monitoring port of the controller, and the ground port of the controller is grounded.
8. A switching power supply, characterized in that the switching power supply comprises: a transformer TR, a power switch tube M1, a feedback device and the switching power supply controller of claim 7;
one end of a primary coil of the transformer TR is connected with the drain electrode of the power tube M1, and the other end of the primary coil of the transformer TR is used as the voltage input end of the switching power supply; one end of a secondary coil of the transformer TR is connected with one end of the feedback device; two ends of a secondary side coil of the transformer TR are used as direct-current voltage output ends of the switching power supply;
the grid electrode of the power tube M1 is connected with the switching signal output end of the switching power supply controller, and the source electrode of the power tube M1 is connected with the current monitoring port of the switching power supply controller;
the other end of the feedback device is connected with a feedback port of the switching power supply controller.
9. The switching power supply according to claim 8, further comprising: a capacitor Cx, a full-wave rectifier diode Dx1, a full-wave rectifier diode Dx2, a full-wave rectifier diode D1, and a capacitor C1;
the two ends of the capacitor Cx are respectively connected with the two ends of the input line voltage; an anode of the full-wave rectifying diode Dx1 is connected to one end of the capacitor Cx and a first end of the full-wave rectifying diode D1, respectively; the cathode of the full-wave rectifying diode Dx1 is respectively connected with the cathode of the full-wave rectifying diode Dx2 and the starting input port VACin of the switching power supply controller; the anode of the full-wave rectifying diode Dx2 is connected to the other end of the capacitor Cx and the second end of the full-wave rectifying diode D1, respectively;
the third end of the full-wave rectifier diode D1 is connected to one end of the capacitor C1 and then grounded, and the fourth end of the full-wave rectifier diode D1 is connected to the other end of the capacitor C1 and the other end of the primary winding of the transformer TR.
10. The switch of claim 8Off-state power supply, characterized in that switching power supply still includes: resistor R1, diode D2, capacitor CVDDAnd an auxiliary coil La;
one end of the resistor R1 is connected to the capacitor CVDDOne end of the resistor R1 is connected with the power supply port of the switching power supply controller, and the other end of the resistor R1 is connected with the cathode of the diode D2; capacitor CVDDThe other end of the first and second electrodes is grounded;
one end of the auxiliary coil La is connected to the anode of the diode D2, and the other end of the auxiliary coil La is grounded.
CN202210441151.5A 2022-04-25 2022-04-25 X capacitor control and start multiplexing circuit, switching power supply controller and switching power supply Pending CN114649932A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115940615A (en) * 2023-03-10 2023-04-07 钰泰半导体股份有限公司 Control chip of switching power supply

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115940615A (en) * 2023-03-10 2023-04-07 钰泰半导体股份有限公司 Control chip of switching power supply

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