CN110932528A - Self-powered control circuit and control method and switching power supply circuit - Google Patents

Self-powered control circuit and control method and switching power supply circuit Download PDF

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Publication number
CN110932528A
CN110932528A CN201911240478.0A CN201911240478A CN110932528A CN 110932528 A CN110932528 A CN 110932528A CN 201911240478 A CN201911240478 A CN 201911240478A CN 110932528 A CN110932528 A CN 110932528A
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switch
turned
bjt
pin
self
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CN110932528B (en
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张波
文鹏
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Hangzhou Biyi Microelectronics Co ltd
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Hangzhou Biyi Microelectronics 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
    • 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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • 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
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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

Abstract

The invention discloses a self-powered control circuit, a control method and a switching power supply circuit, wherein the self-powered control circuit comprises a Bipolar Junction Transistor (BJT), a BJT driver, a unidirectional conduction control device, an energy storage device, a first switch S1, a second switch S2, a third switch S3 and a driving management module. The driving management module is used for controlling the switching states of the first switch S1, the second switch S2 and the third switch S3 according to a current feedback signal and a voltage feedback signal. The invention can completely decouple the control circuit of VDD and the control of the electric quantity of the main circuit; the power supply of VDD is stable and reliable, the electric quantity of the main circuit can be freely adjusted, and the reliable work of the power BJT can be guaranteed.

Description

Self-powered control circuit and control method and switching power supply circuit
Technical Field
The invention belongs to the technical field of microelectronics, relates to a power supply circuit, and particularly relates to a self-powered control circuit, a control method and a switching power supply circuit.
Background
In the isolated power conversion circuit without the auxiliary winding, the control part of a chip power port VDD and the control of the electric quantity of a main circuit are not decoupled.
Referring to fig. 1 and 2, in the conventional control scheme, while the VDD voltage is controlled to a certain range, the peak value of the primary side current of the transformer (and thus the output current of the power supply) is affected; or the pre-off breakpoint of the power BJT. BJTs are short for Bipolar Junction transistors (Bipolar Junction transistors), also commonly referred to as Bipolar transistors.
However, if the pre-close breakpoint is in an unreasonable state, the BJT is either operating in the amplification region or the turn-off delay is greatly increased; while the power loss increases, the primary power is also affected to some extent.
In view of the above, there is an urgent need to design a new power supply method to overcome the above-mentioned defects of the existing power supply methods.
Disclosure of Invention
The invention provides a self-powered control circuit, a control method and a switching power supply circuit, which can completely decouple the control of the electric quantity of a VDD control circuit and a main circuit; the power supply of VDD is ensured to be stable and reliable, the electric quantity (primary side current peak value) of the main circuit can be freely adjusted, and the reliable work of the power BJT can also be ensured.
In order to solve the technical problem, according to one aspect of the present invention, the following technical solutions are adopted:
a self-powered control circuit, the self-powered control circuit comprising:
a bipolar junction transistor BJT;
a BJT driver;
the first unidirectional conduction control device is a diode D1;
the energy storage device is a capacitor C, and the first end of the energy storage device is connected with the second end of the first unidirectional conduction control device;
a first switch S1, a first terminal of the first switch S1 is connected to the emitter of the BJT and a first terminal of the first unidirectional-conduction control device, respectively, and a second terminal of the first switch S1 is connected to a second terminal of the energy storage device;
a second switch S2, wherein a first terminal of the second switch S2 is connected to the base of the bipolar junction transistor BJT, and a second terminal of the second switch S2 is connected to a second terminal of the first switch S1;
a third switch S3, wherein a first terminal of the third switch S3 is connected to the BJT driver, and a second terminal of the third switch S3 is connected to the base of the BJT; and
and the driving management module is used for respectively controlling the switching states of the first switch S1, the second switch S2 and the third switch S3 according to the current feedback signal and the voltage feedback signal.
As an embodiment of the present invention, the driving management module includes a VDD power management circuit, and the VDD power management circuit is respectively connected to the second terminal of the first unidirectional conducting control device, the input terminal of the first switch S1, and the input terminal of the second switch S2; the VDD power management circuit is configured to receive an output signal of the first unidirectional conducting control device, and control a timing of turning off and a duration of turning off the first switch S1 and the second switch S2.
As an embodiment of the present invention, the drive management module includes:
Vcsan amplitude modulation module for receiving the voltage feedback signal and generating a first voltage reference value V of the current feedback signalcs_ref1And a second voltage reference value Vcs_ref2；
A first comparator COM1, the inverting input terminal of the first comparator COM1 receiving a second voltage reference value Vcs_ref2The non-inverting input end of the first comparator COM1 is connected with the current feedback port, and the output end of the first comparator COM1 is connected with the third switch driver; the output end of the third switch driver is connected with a third switch S3;
a second comparator COM2, the inverting input terminal of the second comparator COM2 receiving the first voltage reference value Vcs_ref1The non-inverting input terminal of the second comparator COM2 is connected to the current feedback port, the output terminal of the second comparator COM2 is connected to the second switch driver, and the output terminal of the second switch driver is connected to the second switch S2.
As an embodiment of the present invention, the control state of the self-powered control circuit sequentially includes, in order of occurrence of the control:
the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned on, the BJT is turned on, and the main circuit current flows through the BJT and the first switch S1;
the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned off, the BJT maintains the on state due to the "current tail" effect, and the main circuit current still flows through the BJT and the first switch S1;
the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
According to another aspect of the present invention, there is provided a switching power supply circuit including the self-power control circuit described above.
As an embodiment of the present invention, the switching power supply circuit includes an integrated circuit chip, a capacitor C, a rectifier bridge D, a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor Rcs;
the integrated circuit chip comprises a pin C, a quick start pin OB, a voltage feedback pin FB, a current feedback pin CS, a power supply pin VDD and a reference ground pin GND;
the base electrode of the bipolar junction transistor BJT is connected with a quick starting pin OB, and the collector electrode of the bipolar junction transistor BJT is connected with a pin C;
the second end of the first unidirectional conduction control device is connected with a power supply pin VDD, and the second end of the first switch S1 is connected with a reference ground pin GND;
the first end of the rectifier bridge D is connected with a live wire, the second end of the rectifier bridge D is respectively connected with a pin C of the integrated circuit chip, the first end of a first resistor R1 and the first end of a first capacitor C1, the third end of the rectifier bridge D is connected with a zero line, and the fourth end of the rectifier bridge D is grounded; the second end of the first capacitor C1 is grounded; a second end of the first resistor R1 is connected with an OB pin of the integrated circuit chip;
the FB pin of the integrated circuit chip is respectively connected with the second end of the second resistor R2 and the first end of the third resistor R3; a VDD pin of the integrated circuit chip is connected with a first end of the capacitor C, and a GND pin of the integrated circuit chip is respectively connected with a second end of the capacitor C and a first end of the fourth resistor Rcs; the CS pin of the integrated circuit chip is respectively connected with the second end of the fourth resistor Rcs, the first end of the second resistor R2 and the first end of the primary winding of the transformer, and the second end of the third resistor R3 and the second end of the primary winding of the transformer are respectively grounded.
According to still another aspect of the present invention, the present invention provides a control method of the above self-powered control circuit, including: the self-powered control is realized by controlling the on or off of the first switch S1, the second switch S2 and the third switch S3.
As an embodiment of the present invention, the control method includes:
(1) controlling the first switch S1 to be conducted, the second switch S2 to be disconnected, the third switch S3 to be conducted, the bipolar junction transistor BJT to be conducted, the main circuit current flows through the bipolar junction transistor BJT and the first switch S1, and the Vcs voltage signal representing the transformer inductance current is increased linearly;
(2) the VDD power supply management circuit controls the first switch S1 to be switched off; the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
(3) the Vcs voltage signal reaches a second voltage reference value Vcs_ref2When the current source is turned on, the first switch S1 is turned on, the second switch S2 is turned off, and the third switch S3 is turned off, the BJT maintains the on state due to the "current tailing" effect, and the main circuit current still flows through the BJT and the first switch S1;
(4) when the collector voltage signal Vc of the bipolar junction transistor BJT reaches the first voltage reference value Vcs_ref1When the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
As an embodiment of the present invention, the control method further includes: and a VDD power supply management step, receiving an output signal of the first unidirectional conduction control device, and controlling the turn-off time and the turn-off duration time of the first switch S1 and the second switch S2.
As an embodiment of the present invention, the control method further includes: vcsAn amplitude modulation step, receiving a voltage feedback signal of the voltage feedback pin FB, and generating a first voltage reference value V of the current feedback signal according to the received voltage feedback signalcs_ref1And a second voltage reference value Vcs_ref2。
The invention has the beneficial effects that: the self-powered control circuit, the control method and the switching power supply circuit provided by the invention have the advantages that the control of the electric quantity of the VDD control circuit and the main circuit is completely decoupled; the power supply of VDD is ensured to be stable and reliable, the electric quantity (primary side current peak value) of the main circuit can be freely adjusted, and the reliable work of the power BJT can also be ensured. The invention can be applied to an isolated power conversion circuit without an auxiliary winding, and solves the problem of VDD self power supply.
Drawings
Fig. 1 is a circuit schematic diagram of an isolated power conversion circuit without an auxiliary winding.
Fig. 2 is a circuit diagram of a conventional isolated switching power supply without an auxiliary winding.
Fig. 3 is a circuit diagram of a self-powered control circuit according to an embodiment of the invention.
Fig. 4 is a circuit diagram of a switching power supply circuit according to an embodiment of the invention.
FIG. 5 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 7 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 8 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 9 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 10 is a schematic diagram of a portion of a self-powered control circuit according to an embodiment of the present invention.
FIG. 11 is a waveform illustrating operation of the self-powered control circuitry according to an embodiment of the present invention.
FIG. 12 is a waveform illustrating operation of the self-powered control circuitry according to an embodiment of the present invention.
Detailed Description
Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
The description in this section is for several exemplary embodiments only, and the present invention is not limited only to the scope of the embodiments described. It is within the scope of the present disclosure and protection that the same or similar prior art means and some features of the embodiments may be interchanged.
"coupled" or "connected" in this specification includes direct connection and also includes indirect connection, such as connection through an electrically conductive medium, such as a conductor, where the electrically conductive medium may include parasitic inductance or parasitic capacitance. But also may include connections through other active or passive devices, such as through switches, follower circuits, etc., that are known to those skilled in the art to accomplish the same or similar functional objectives.
Fig. 3 is a schematic circuit diagram of a self-powered control circuit according to an embodiment of the present invention; referring to fig. 3, in an embodiment of the present invention, the self-powered control circuit includes: a bipolar junction transistor BJT, a BJT driver 3, a first unidirectional conduction control device, an energy storage device, a first switch S1, a second switch S2, and a third switch S3.
The first end of the energy storage device is connected with the second end of the first unidirectional conduction control device; a first terminal of the first switch S1 is connected to the emitter of the bipolar junction transistor BJT and a first terminal of the first unidirectional conduction control device, respectively, and a second terminal of the first switch S1 is connected to a second terminal of the energy storage device; a first terminal of the second switch S2 is connected to the base of the bipolar junction transistor BJT, and a second terminal of the second switch S2 is connected to a second terminal of the first switch S1; a first terminal of the third switch S3 is connected to the BJT driver, and a second terminal of the third switch S3 is connected to the base of the bipolar junction transistor BJT.
In an embodiment of the present invention, the BJT is a first transistor Q1; the first unidirectional turn-on control device is a first diode D1; the energy storage device is a capacitor C.
In an embodiment of the invention, the first switch S1, the second switch S2, and the third switch S3 are MOS transistors, but may be other power transistors.
FIG. 5 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 5, in an embodiment of the invention, the self-power supply control circuit further includes a driving management module 1, and the driving management module 1 is configured to control the switching states of the first switch S1, the second switch S2 and the third switch S3. Illustratively, the driving management module is configured to control the switching states of the first switch S1, the second switch S2, and the third switch S3 according to a current feedback signal and a voltage feedback signal, respectively. The switching state of the second switch S2 can be controlled according to the current feedback signal and the voltage feedback signal, the switching state of the third switch S3 can be controlled according to the current feedback signal and the voltage feedback signal, and the switching state of the first switch S1 can be indirectly controlled through the current feedback signal and the voltage feedback signal.
The invention discloses an integrated circuit chip which comprises the self-powered control circuit. FIG. 5 is a schematic diagram of an integrated circuit chip according to an embodiment of the present invention. Referring to fig. 5, in an embodiment of the invention, the integrated circuit chip includes a pin C, a fast start pin OB, a voltage feedback pin FB, a current feedback pin CS, a power supply pin VDD, and a ground reference pin GND. The base electrode of the bipolar junction transistor BJT is connected with a quick starting pin OB, and the collector electrode of the bipolar junction transistor BJT is connected with a pin C; the second end of the first unidirectional conducting control device is connected with a power supply pin VDD, and the second end of the first switch S1 is connected with a reference ground pin GND.
FIG. 6 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 6, in an embodiment of the invention, the driving management module 1 is connected to a current feedback pin CS, and controls a switching state of the second switch S2 and/or the third switch S3 according to a feedback signal of the current feedback pin CS.
FIG. 7 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 7, in an embodiment of the invention, the driving management module 1 includes a VDD power management circuit 7, and the VDD power management circuit 7 is respectively connected to the second terminal of the first unidirectional conducting control device, the input terminal of the first switch S1, and the input terminal of the second switch S2; the VDD power management circuit is configured to receive an output signal of the first unidirectional conducting control device, and control a timing of turning off and a duration of turning off the first switch S1 and the second switch S2.
FIG. 8 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 8, in an embodiment of the invention, the driving management module 1 includes VcsAn amplitude modulation module 5; vcsThe amplitude modulation module 5 is used for receiving the voltage feedback signal and generating a first voltage reference value V of the current feedback signalcs_ref1And a second voltage reference value Vcs_ref2。
In an embodiment of the present invention, the driving management module 1 further includes a first comparator COM1, a second comparator COM 2; the inverting input terminal of the first comparator COM1 receives the second voltage reference value Vcs_ref2The positive phase input end of the first comparator COM1 is connected with the current feedback port, and the output end of the first comparator COM1 is connected with the driving pipeline module 1; the output end of the drive pipeline module 1 is connected with a third switch S3. The inverting input terminal of the second comparator COM2 receives the first voltage reference value Vcs_ref1Positive phase output of the second comparator COM2The input end of the second comparator COM2 is connected with the current feedback port, the output end of the second comparator COM2 is connected with the driving pipeline module 1, and the output end of the driving pipeline module 1 is connected with the second switch S2.
FIG. 9 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 9, in an embodiment of the invention, compared with the self-power control circuit shown in fig. 8, the driving management module 1 further includes a VDD power management circuit 7.
FIG. 10 is a schematic diagram of a portion of a self-powered control circuit in accordance with an embodiment of the present invention; referring to fig. 10, in an embodiment of the invention, the driving management module includes a first switch driver 11, a second switch driver 12, a third switch driver 13, a VDD power management circuit 7, a VcsThe amplitude modulation module 5, the first comparator COM1 and the second comparator COM 2.
The output of the first switch driver 11 is connected with a first switch S1; the output of the second switch driver 12 is connected to the second switch S2; the output of the third switch driver 13 is connected to the third switch S3. The VDD supply management circuit 7 is connected to the second terminal of the first unidirectional conductive control device (the first diode D1), the input terminal of the first switch driver 11, and the input terminal of the second switch driver 12, respectively. The VDD power management circuit is configured to receive an output signal of the first unidirectional conducting control device, and control a timing of turning off and a duration of turning off the first switch S1 and the second switch S2.
VcsThe amplitude modulation module 5 is used for receiving a voltage feedback signal (corresponding to a voltage feedback pin FB of the ic chip) and generating a first voltage reference V of the current feedback signalcs_ref1And a second voltage reference value Vcs_ref2。
The inverting input terminal of the first comparator COM1 receives a second voltage reference value Vcs_ref2The non-inverting input terminal of the first comparator COM1 is connected to the current feedback port (corresponding to the integrated circuit chip current feedback pin CS), and the output terminal of the first comparator COM1 is connected to the third switch driver 13. The inverting input terminal of the second comparator COM2 receives a first voltage reference value Vcs_ref1And the non-inverting input terminal of the second comparator COM2 is connectedConnected to the current feedback port, the output terminal of the second comparator COM2 is connected to the second switch driver 12.
FIG. 12 is a waveform illustrating operation of the self-powered control circuitry according to an embodiment of the present invention; referring to fig. 12, in an embodiment of the invention, during the idle time of the power supply, i.e. when the power transformer is not excited or demagnetized, the second switch S2 and the first switch S1 are allowed to be turned off at any time, and the current of the OB pin is used to turn on the BJT to supply power to the energy storage device; the timing and duration of the turn-off of the first switch S1 and the second switch S2 are determined by the VDD power management circuit.
In an embodiment of the present invention, the self-powered control circuit has four switch states in a sequential order (e.g., the sequential order in which control occurs):
(1) the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned on, the BJT is turned on, and the main circuit current flows through the BJT and the first switch S1;
(2) the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
(3) the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned off, the BJT maintains the on state due to the "current tail" effect, and the main circuit current still flows through the BJT and the first switch S1;
(4) the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
The invention discloses a switching power supply circuit which comprises the self-powered control circuit.
FIG. 4 is a circuit diagram of a switching power supply circuit according to an embodiment of the present invention; referring to fig. 4, in an embodiment of the invention, the switching power supply circuit includes an integrated circuit chip, a capacitor C, a rectifier bridge D, a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor Rcs. It should be noted that the BJT can be optionally integrated in the control circuit (i.e. the integrated circuit chip described above) or can be external.
The integrated circuit chip comprises a pin C (collector of BJT), a quick start pin OB, a voltage feedback pin FB, a current feedback pin CS, a power supply pin VDD and a reference ground pin GND. The base electrode of the bipolar junction transistor BJT is connected with a quick starting pin OB, and the collector electrode of the bipolar junction transistor BJT is connected with a pin C. The second end of the first unidirectional conducting control device is connected with a power supply pin VDD, and the second end of the first switch S1 is connected with a reference ground pin GND.
The first end of the rectifier bridge D is connected with a live wire, the second end of the rectifier bridge D is respectively connected with a pin C of the integrated circuit chip, the first end of a first resistor R1 and the first end of a first capacitor C1, the third end of the rectifier bridge D is connected with a zero line, and the fourth end of the rectifier bridge D is grounded; the second end of the first capacitor C1 is grounded; a second terminal of the first resistor R1 is connected to the OB pin of the integrated circuit chip.
The FB pin of the integrated circuit chip is respectively connected with the second end of the second resistor R2 and the first end of the third resistor R3; a VDD pin of the integrated circuit chip is connected with a first end of the capacitor C, and a GND pin of the integrated circuit chip is respectively connected with a second end of the capacitor C and a first end of the fourth resistor Rcs; the CS pin of the integrated circuit chip is respectively connected with the second end of the fourth resistor Rcs, the first end of the second resistor R2 and the first end of the primary winding of the transformer, and the second end of the third resistor R3 and the second end of the primary winding of the transformer are respectively grounded.
The invention discloses a control method of the self-powered control circuit, which comprises the following steps: the self-power supply control is realized by controlling the on or off of the first switch S1, the second switch S2 and the third switch S3.
FIG. 11 is a waveform illustrating operation of the self-powered control circuitry according to an embodiment of the present invention; referring to fig. 11, in an embodiment of the present invention, the control method includes:
(1) controlling the first switch S1 to be conducted, the second switch S2 to be disconnected, the third switch S3 to be conducted, the bipolar junction transistor BJT to be conducted, the main circuit current flows through the bipolar junction transistor BJT and the first switch S1, and the Vcs voltage signal representing the transformer inductance current is increased linearly;
(2) the VDD power supply management circuit controls the first switch S1 to be switched off; the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
(3) the Vcs voltage signal reaches a second voltage reference value Vcs_ref2When the current source is turned on, the first switch S1 is turned on, the second switch S2 is turned off, and the third switch S3 is turned off, the BJT maintains the on state due to the "current tailing" effect, and the main circuit current still flows through the BJT and the first switch S1;
(4) when the collector voltage signal Vc of the bipolar junction transistor BJT reaches the first voltage reference value Vcs_ref1When the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
Control of the third switch S3 only following the second voltage reference Vcs_ref2Second voltage reference value V related to Vcscs_ref2Generated by an amplitude modulation module according to VFB, Vcs is current feedback; during the period of increasing Vcs amplitude, the second switch S2 remains off, and when Vcs reaches the first voltage reference Vcs _ ref1, the second switch S2 is turned on and the BJT is immediately turned off. Therefore, Vcs (transformer primary current) and control of the third switch S3 is independent of VDD supply control.
After the third switch S3 is turned off, the first switch S1 is turned off; the rising edge of the first switch S1 is modulated by the VDD supply management circuit; when the collector voltage signal Vc of the BJT reaches the first voltage reference value Vcs_ref1When so, the second switch S2 is on; in the same period, the first switch S1 is turned on again before the second switch S2 is turned on. In an extreme case, the rising edge of the first switch S1Gate may coincide with the falling edge of the third switch S3 Gate; or may coincide with the rising edge of the second switch S2 gate (equivalent to the first switch)S1 is not turned off for this period).
In an embodiment of the present invention, the control method includes:
(1) controlling the first switch S1 to be turned on, the second switch S2 to be turned off, the third switch S3 to be turned on, the BJT to be turned on, and the main circuit current to flow through the BJT and the first switch S1;
(2) controlling the first switch S1 to be turned off, the second switch S2 to be turned off, and the third switch S3 to be turned off, keeping the bipolar junction transistor BJT on under the effect of 'current tailing', and charging the energy storage device by current flowing through the bipolar junction transistor BJT and the first unidirectional conduction control device;
(3) controlling the first switch S1 to be turned on, the second switch S2 to be turned off, and the third switch S3 to be turned off, so that the BJT maintains the on state due to the "current tail" effect, and the main circuit current still flows through the BJT and the first switch S1;
(4) the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is turned off completely.
In summary, the self-powered control circuit, the control method and the switching power supply circuit provided by the invention completely decouple the control of the power of the VDD control circuit and the power of the main circuit; the power supply of VDD is ensured to be stable and reliable, the electric quantity (primary side current peak value) of the main circuit can be freely adjusted, and the reliable work of the power BJT can also be ensured. The invention can be applied to an isolated power conversion circuit without an auxiliary winding, and solves the problem of VDD self power supply.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The description and applications of the invention herein are illustrative and are not intended to limit the scope of the invention to the embodiments described above. Variations and modifications of the embodiments disclosed herein are possible, and alternative and equivalent various components of the embodiments will be apparent to those skilled in the art. It will be clear to those skilled in the art that the present invention may be embodied in other forms, structures, arrangements, proportions, and with other components, materials, and parts, without departing from the spirit or essential characteristics thereof. Other variations and modifications of the embodiments disclosed herein may be made without departing from the scope and spirit of the invention.

Claims (10)

1. A self-powered control circuit, the self-powered control circuit comprising:
a bipolar junction transistor BJT;
a BJT driver;
the first unidirectional conduction control device is a diode D1;
the energy storage device is a capacitor C, and the first end of the energy storage device is connected with the second end of the first unidirectional conduction control device;
a first switch S1, a first terminal of the first switch S1 is connected to the emitter of the BJT and a first terminal of the first unidirectional-conduction control device, respectively, and a second terminal of the first switch S1 is connected to a second terminal of the energy storage device;
a second switch S2, wherein a first terminal of the second switch S2 is connected to the base of the bipolar junction transistor BJT, and a second terminal of the second switch S2 is connected to a second terminal of the first switch S1;
a third switch S3, wherein a first terminal of the third switch S3 is connected to the BJT driver, and a second terminal of the third switch S3 is connected to the base of the BJT; and
and the driving management module is used for respectively controlling the switching states of the first switch S1, the second switch S2 and the third switch S3 according to the current feedback signal and the voltage feedback signal.
2. The self-powered control circuit of claim 1, wherein:
the driving management module comprises a VDD power supply management circuit, and the VDD power supply management circuit is respectively connected with the second end of the first unidirectional conduction control device, the input end of the first switch S1 and the input end of the second switch S2; the VDD power management circuit is configured to receive an output signal of the first unidirectional conducting control device, and control the turn-off time and the turn-off duration of the first switch S1 and the second switch S2.
3. The self-powered control circuit of claim 1, wherein:
the drive management module includes:
Vcsan amplitude modulation module for receiving the voltage feedback signal and generating a first voltage reference value V of the current feedback signalcs_ref1And a second voltage reference value Vcs_ref2；
A first comparator COM1, the inverting input terminal of the first comparator COM1 receiving a second voltage reference value Vcs_ref2The non-inverting input end of the first comparator COM1 is connected with the current feedback port, and the output end of the first comparator COM1 is connected with the third switch driver; the output end of the third switch driver is connected with a third switch S3;
a second comparator COM2, the inverting input terminal of the second comparator COM2 receiving the first voltage reference value Vcs_ref1The non-inverting input terminal of the second comparator COM2 is connected to the current feedback port, the output terminal of the second comparator COM2 is connected to the second switch driver, and the output terminal of the second switch driver is connected to the second switch S2.
4. The self-powered control circuit of claim 1, wherein the control states of the self-powered control circuit sequentially comprise, in order of control occurrence:
the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned on, the BJT is turned on, and the main circuit current flows through the BJT and the first switch S1;
the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
the first switch S1 is turned on, the second switch S2 is turned off, the third switch S3 is turned off, the BJT maintains the on state due to the "current tail" effect, and the main circuit current still flows through the BJT and the first switch S1;
the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
5. A switching power supply circuit, characterized in that it comprises a self-powered control circuit according to any one of claims 1 to 4.
6. The switching power supply circuit according to claim 5, wherein:
the switching power supply circuit comprises an integrated circuit chip, a capacitor C, a rectifier bridge D, a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor Rcs;
the integrated circuit chip comprises a pin C, a quick start pin OB, a voltage feedback pin FB, a current feedback pin CS, a power supply pin VDD and a reference ground pin GND;
the base electrode of the bipolar junction transistor BJT is connected with a quick starting pin OB, and the collector electrode of the bipolar junction transistor BJT is connected with a pin C;
the second end of the first unidirectional conduction control device is connected with a power supply pin VDD, and the second end of the first switch S1 is connected with a reference ground pin GND;
the first end of the rectifier bridge D is connected with a live wire, the second end of the rectifier bridge D is respectively connected with a pin C of the integrated circuit chip, the first end of a first resistor R1 and the first end of a first capacitor C1, the third end of the rectifier bridge D is connected with a zero line, and the fourth end of the rectifier bridge D is grounded; the second end of the first capacitor C1 is grounded; a second end of the first resistor R1 is connected with an OB pin of the integrated circuit chip;
the FB pin of the integrated circuit chip is respectively connected with the second end of the second resistor R2 and the first end of the third resistor R3; a VDD pin of the integrated circuit chip is connected with a first end of the capacitor C, and a GND pin of the integrated circuit chip is respectively connected with a second end of the capacitor C and a first end of the fourth resistor Rcs; the CS pin of the integrated circuit chip is respectively connected with the second end of the fourth resistor Rcs, the first end of the second resistor R2 and the first end of the primary winding of the transformer, and the second end of the third resistor R3 and the second end of the primary winding of the transformer are respectively grounded.
7. A method of controlling a self-powered control circuit as claimed in any one of claims 1 to 4, comprising: the self-powered control is realized by controlling the on or off of the first switch S1, the second switch S2 and the third switch S3.
8. The control method according to claim 7, characterized in that:
the control method comprises the following steps:
(1) controlling the first switch S1 to be conducted, the second switch S2 to be disconnected, the third switch S3 to be conducted, the bipolar junction transistor BJT to be conducted, the main circuit current flows through the bipolar junction transistor BJT and the first switch S1, and the Vcs voltage signal representing the transformer inductance current is increased linearly;
(2) the VDD power supply management circuit controls the first switch S1 to be switched off; the first switch S1 is turned off, the second switch S2 is turned off, the third switch S3 is turned off, the BJT is kept on under the "current tailing" effect, and current flows through the BJT and the first unidirectional on control device to charge the energy storage device;
(3) the Vcs voltage signal reaches a second voltage reference value Vcs_ref2When the current source is turned on, the first switch S1 is turned on, the second switch S2 is turned off, and the third switch S3 is turned off, the BJT maintains the on state due to the "current tailing" effect, and the main circuit current still flows through the BJT and the first switch S1;
(4) when the collector voltage signal Vc of the bipolar junction transistor BJT reaches the first voltage reference value Vcs_ref1When the first switch S1 is turned on, the second switch S2 is turned on, the third switch S3 is turned off, and the BJT is completely turned off.
9. The control method according to claim 7, characterized in that:
the control method further includes: and a VDD power supply management step, receiving an output signal of the first unidirectional conduction control device, and controlling the turn-off time and the turn-off duration of the first switch S1 and the second switch S2.
10. The control method according to claim 7, characterized in that:
the control method further includes: vcsAn amplitude modulation step, receiving a voltage feedback signal of the voltage feedback pin FB, and generating a first voltage reference value V of the current feedback signal according to the received voltage feedback signalcs_ref1And a second voltage reference value Vcs_ref2。
CN201911240478.0A 2019-12-06 2019-12-06 Self-powered control circuit and control method and switching power supply circuit Active CN110932528B (en)

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CN106685236A (en) * 2017-03-10 2017-05-17 绍兴光大芯业微电子有限公司 Circuit structure for isolated switch power without auxiliary winding and with controllable primary side current
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