阅读说明：本技术 一种控制电路、控制方法和电压变换电路 (Control circuit, control method and voltage conversion circuit ) 是由 林官秋 胡长伟 金伟祥 于 2021-03-17 设计创作，主要内容包括：本发明提出一种控制电路、控制方法和电压变换电路,其中,控制电路包括供电端口、反馈信号端口和参考地端口,控制电路还包括用于形成不同反馈通路的第一开关管,所述第一开关管与反馈信号端口耦接,第一开关管关断时,反馈信号端口与供电端口之间形成第一反馈通路并提供电压反馈信号,第一开关管导通时,反馈信号端口基于第一开关管形成第二反馈通路并提供电压反馈信号。本发明提出的控制电路能够实现兼容光耦高电位连接和低电位连接的闭环反馈,优化系统调试、减少物料成本,提高电源系统的适配性和便利性,提供给用户更多选择空间。(The invention provides a control circuit, a control method and a voltage conversion circuit, wherein the control circuit comprises a power supply port, a feedback signal port and a reference ground port, the control circuit further comprises a first switching tube for forming different feedback paths, the first switching tube is coupled with the feedback signal port, when the first switching tube is turned off, a first feedback path is formed between the feedback signal port and the power supply port and provides a voltage feedback signal, and when the first switching tube is turned on, the feedback signal port forms a second feedback path based on the first switching tube and provides the voltage feedback signal. The control circuit provided by the invention can realize the closed loop feedback of the compatible optocoupler high potential connection and low potential connection, optimize the system debugging, reduce the material cost, improve the adaptability and the convenience of the power supply system and provide more selection space for users.)

1. The control circuit is characterized by comprising a power supply port, a feedback signal port and a reference ground port, and further comprising a first switching tube for forming different feedback paths, wherein the first switching tube is coupled with the feedback signal port, when the first switching tube is turned off, the first feedback path is formed between the feedback signal port and the power supply port and provides a voltage feedback signal, and when the first switching tube is turned on, the feedback signal port forms a second feedback path based on the first switching tube and provides the voltage feedback signal.

2. The control circuit of claim 1, wherein the first switch transistor is a first field effect transistor having a gate connected to a fixed voltage source, a source coupled to the second feedback path, and a drain coupled to the feedback signal port, wherein an output voltage of the fixed voltage source is less than an output voltage of the power supply port.

3. The control circuit of claim 1 or 2, wherein the first switch transistor is a PMOS transistor.

4. The control circuit of claim 1, wherein the first feedback path comprises a second switch tube and a second resistor, the second switch tube and the second resistor are sequentially coupled between the power supply port and the feedback signal port, the feedback signal port is grounded through the third switch tube and the sampling feedback circuit, the second switch tube and the third switch tube are conducted when the first switch tube is turned off, and the voltage of the feedback signal port is pulled up to the power supply port voltage through the second resistor and the second switch tube; when the first switch tube is switched on, the second switch tube is switched off.

5. The control circuit of claim 4, wherein the second switch is a second field effect transistor having a gate connected to the digital power supply port, a source coupled to the feedback signal port through a second resistor, and a drain coupled to the power supply port.

6. The control circuit of claim 4 or 5, wherein the second switch tube is an NMOS tube.

7. The control circuit of claim 1, wherein the second feedback path further comprises a current mirror and a third resistor, wherein an input stage of the current mirror is coupled to the first switch tube, and an output stage of the current mirror is connected to a fixed voltage source through the third resistor and grounded through the third switch tube and the sampling feedback circuit, and an output voltage of the fixed voltage source is less than an output voltage of the power supply port.

8. The control circuit of claim 7, wherein the first switch is a first field effect transistor having a gate connected to a fixed voltage source, a source coupled to the input stage of the current mirror, and a drain coupled to the feedback signal port.

9. The control circuit of claim 4 or 7, wherein the third switch transistor is a third effect transistor having a gate coupled to the output stage of the current mirror, a source coupled to the sampling feedback circuit, and a drain coupled to the feedback signal port.

10. The control circuit of claim 9, wherein the sampling feedback circuit comprises a fourth switching tube and a first resistor, and the fourth switching tube and the first resistor are sequentially coupled between the source of the third switching tube and the ground.

11. The control circuit of claim 10, wherein the fourth switch is a fourth field effect transistor having a gate connected to the modulation signal, a drain coupled to the source of the third switch, and a source connected to ground through the first resistor.

12. The control circuit of claim 7 or 9, wherein the third switch transistor is an NMOS transistor.

13. A voltage conversion circuit, comprising an optical coupler and the control circuit as claimed in any one of claims 1 to 12, wherein a feedback terminal of the optical coupler is coupled to an output terminal of the voltage conversion circuit for obtaining a feedback signal of a voltage at the output terminal of the voltage conversion circuit; the receiving end of the optical coupler is coupled to the input end of the voltage conversion circuit through the control circuit and used for receiving a feedback signal of the feedback end of the optical coupler and feeding the feedback signal back to the input end of the voltage conversion circuit through the control circuit.

14. The voltage conversion circuit of claim 13, wherein a receiving end of the optical coupler is coupled between the power supply port and the feedback signal port of the control circuit to form an optical coupler floating connection.

15. The voltage conversion circuit of claim 13, wherein a receiving end of the optical coupler is coupled between the feedback signal port and the reference ground port to form an optical coupler ground connection.

16. A control method is characterized in that closed-loop feedback for different optical coupling connection architectures is used, feedback paths are respectively formed according to the connection or disconnection of a first switch tube to carry out sampling of optical coupling feedback current, the first switch tube is coupled with a feedback signal port, and a first feedback path is formed between the feedback signal port and a power supply port when the first switch tube is disconnected; when the first switch tube is conducted, the feedback signal port forms a second feedback path based on the first switch tube.

17. A control method based on optical coupler for feedback is characterized in that when the optical coupler is coupled between a first port and a second port of a control circuit, a first switch tube in the control circuit is turned off, and a first feedback path is formed in the control circuit; when the optical coupler is coupled between the second port and the third port of the control circuit, a first switch tube in the control circuit is conducted, and a second feedback path is formed in the control circuit.

Technical Field

The present invention relates to the field of electronics, and in particular, but not exclusively, to a control circuit, a control method, and a voltage conversion circuit.

Background

The optical coupler feedback is mainly used in an isolated secondary feedback (SSR) control application occasion, and the main purpose of the optical coupler feedback is to obtain a feedback signal of a secondary side in real time through the optical coupler at a primary side while isolating an original side and the secondary side from electric connection.

In a typical application, the SSR optocoupler feedback is based on the coupling circuit shown in fig. 1, and is referred to as a Low-Side connection. The ratio of signals fed back and received by the feedback end U1A and the receiving end U1B of the optical coupler is 1: 1, the CTR transmission ratio is generally set to about 1. An internal circuit structure of the optocoupler feedback controller 1 is shown in fig. 2, namely, a typical SSR internal pull-up, and an FB signal under the condition of sampling the optocoupler pull-down current in real time is used for closed-loop feedback.

In addition to the above application, some system circuits adopt another feedback connection method as shown in fig. 3, which is called High-Side connection, a feedback end U1A of the optical coupler transmits a feedback signal of an output end to a receiving end U1B, the receiving end U1B is connected to a primary Side of the circuit through the controller 1, and an internal control circuit structure of the controller 1 fed back by the optical coupler is shown in fig. 4. For a common FB internal modulation circuit with the same structure, after High-Side connection is adopted, normal amplitude-frequency power regulation can be realized only after the internal part needs to be subjected to inversion operation, and a resistor pull-down circuit needs to be arranged inside or outside to provide an optocoupler release loop.

The optical coupling connection mode of the two architectures needs to be realized by matching with different internal circuits, and the optical coupling High-side and Low-side connection cannot be compatible on the same control circuit, so that the product application limitation exists, and the product universality is unfavorable. In view of the above, it is desirable to provide a new control circuit structure or control method to solve at least some of the above problems.

Disclosure of Invention

Aiming at one or more problems in the prior art, the invention provides a control circuit, which realizes the closed loop feedback of compatible optocoupler high potential connection and low potential connection, optimizes system debugging, reduces material cost, improves the adaptability and convenience of a power supply system, and provides more selection space for users.

The technical solution for realizing the purpose of the invention is as follows:

the invention discloses a control circuit, which is used for closed-loop feedback of different optical coupling connection architectures, and comprises a power supply port, a feedback signal port and a reference ground port, and further comprises a first switching tube used for forming different feedback paths, wherein the first switching tube is coupled with the feedback signal port, when the first switching tube is turned off, a first feedback path is formed between the feedback signal port and the power supply port and provides a voltage feedback signal, and when the first switching tube is turned on, the feedback signal port forms a second feedback path based on the first switching tube and provides the voltage feedback signal.

In an embodiment of the invention, the first switch tube is a first field effect transistor, a gate of the first field effect transistor is connected to a fixed voltage source, a source of the first field effect transistor is coupled to the second feedback path, a drain of the first field effect transistor is coupled to the feedback signal port, and an output voltage of the fixed voltage source is smaller than an output voltage of the power supply port.

In an embodiment of the invention, the first switch transistor is a PMOS transistor.

In an embodiment of the present invention, the first feedback path includes a second switch tube and a second resistor, the second switch tube and the second resistor are sequentially coupled between the power supply port and the feedback signal port, the feedback signal port is grounded through a third switch tube and the sampling feedback circuit, the second switch tube and the third switch tube are turned on when the first switch tube is turned off, and the voltage of the feedback signal port is pulled up to the voltage of the power supply port through the second resistor and the second switch tube; when the first switch tube is switched on, the second switch tube is switched off.

In an embodiment of the invention, the second switch is a second field effect transistor, the gate is connected to the power supply port of the digital power supply, the source is coupled to the feedback signal port through a second resistor, and the drain is coupled to the power supply port.

In an embodiment of the invention, the second switch tube is an NMOS tube.

In an embodiment of the present invention, the second feedback path further includes a current mirror and a third resistor, wherein an input stage of the current mirror is coupled to the first switching tube, an output stage is connected to a fixed voltage source through the third resistor, and is grounded through the third switching tube and the sampling feedback circuit, and an output voltage of the fixed voltage source is less than an output voltage of the power supply port.

In an embodiment of the invention, the first switch transistor is a first field effect transistor, a gate of the first field effect transistor is connected to the fixed voltage source, a source of the first field effect transistor is coupled to the current mirror input stage, and a drain of the first field effect transistor is coupled to the feedback signal port.

In an embodiment of the invention, the third switch tube is a third effect transistor, a gate of the third effect transistor is coupled to the output stage of the current mirror, a source of the third effect transistor is grounded through the sampling feedback circuit, and a drain of the third effect transistor is coupled to the feedback signal port.

In an embodiment of the present invention, the sampling feedback circuit includes a fourth switching tube and a first resistor, and the fourth switching tube and the first resistor are sequentially coupled between the source of the third switching tube and ground.

In an embodiment of the invention, the fourth switching tube is a fourth field effect transistor, a gate of the fourth field effect transistor is connected to the modulation signal, a drain of the fourth field effect transistor is coupled to a source of the third switching tube, and the source is grounded through the first resistor.

In an embodiment of the invention, the third switch transistor is an NMOS transistor.

The invention discloses a voltage conversion circuit, which comprises an optical coupler and any one of the control circuits, wherein the feedback end of the optical coupler is coupled to the output end of the voltage conversion circuit and is used for acquiring a feedback signal of the voltage at the output end of the voltage conversion circuit; the receiving end of the optical coupler is coupled to the input end of the voltage conversion circuit through the control circuit and used for receiving a feedback signal of the feedback end of the optical coupler and feeding the feedback signal back to the input end of the voltage conversion circuit through the control circuit.

In an embodiment of the present invention, a receiving end of the optical coupler is coupled between the power supply port and the feedback signal port of the control circuit to form an optical coupler floating connection.

In an embodiment of the present invention, a receiving end of the optical coupler is coupled between the feedback signal port and the reference ground port to form an optical coupler ground connection.

The invention discloses a control method, which is used for closed-loop feedback of different optical coupling connection architectures, and respectively forms a feedback path for sampling optical coupling feedback current according to the connection or disconnection of a first switch tube, wherein the first switch tube is coupled with a feedback signal port, and a first feedback path is formed between the feedback signal port and a power supply port when the first switch tube is disconnected; when the first switch tube is conducted, the feedback signal port forms a second feedback path based on the first switch tube.

The invention discloses a control method for feedback based on an optocoupler, wherein when the optocoupler is coupled between a first port and a second port of a control circuit, a first switch tube in the control circuit is turned off, and a first feedback path is formed in the control circuit; when the optical coupler is coupled between the second port and the third port of the control circuit, a first switch tube in the control circuit is conducted, and a second feedback path is formed in the control circuit.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

the control circuit provided by the invention can be compatible with closed loop feedback of optical coupling floating connection and grounding connection, saves great circuit resources in design, optimizes system debugging, reduces material cost, is beneficial to improving the adaptability and convenience of a power supply system, and provides more selection space for users.

Drawings

Fig. 1 is a circuit schematic diagram of a prior art opto-coupler Low-side connection.

Fig. 2 is a schematic diagram of an internal circuit of a controller connected by optocouplers Low-side in the prior art.

Fig. 3 is a circuit schematic diagram of a prior art opto-coupler High-side connection.

Fig. 4 is a schematic circuit diagram of the internal circuit of the controller connected by the optocoupler High-side in the prior art.

FIG. 5 is a diagram of a control circuit according to an embodiment of the invention.

Fig. 6 is a schematic circuit diagram of the Low-side connection of the optocoupler according to an embodiment of the present invention.

Fig. 7 is a schematic circuit diagram of a High-side connection of the optocoupler according to another embodiment of the present invention.

The same reference numbers in different drawings identify the same or similar elements or components.

Detailed Description

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. Combinations of different embodiments, and substitutions of features from different embodiments, or similar prior art means may be substituted for or substituted for features of the embodiments shown and described.

The term "coupled" or "connected" in this specification includes both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as a conductor, wherein the electrically conductive medium may contain parasitic inductance or parasitic capacitance, or through an intermediate circuit or component as described in the embodiments in the specification; indirect connections may also include connections through other active or passive devices that perform the same or similar function, such as connections through switches, signal amplification circuits, follower circuits, and so on. "plurality" or "plurality" means two or more.

According to one aspect of the present invention, a control circuit is shown in fig. 5 for closed loop feedback for different optical coupling architectures. The control circuit comprises a power supply port VDD, a feedback signal port FB and a ground reference port GND, the control circuit further comprises a first switch tube S1 for forming different feedback paths, the first switch tube S1 is coupled with the feedback signal port FB, when the first switch tube S1 is turned off, a first feedback path is formed between the feedback signal port FB and the power supply port VDD and a voltage feedback signal is provided, and when the first switch tube S1 is turned on, the feedback signal port FB forms a second feedback path based on the first switch tube S1 and provides the voltage feedback signal. In one embodiment, the first switch tube S1 is a first field effect transistor having a gate connected to a fixed voltage source DVDD, a source coupled to the second feedback path, and a drain coupled to the feedback signal port FB, wherein the output voltage of the fixed voltage source DVDD is less than the output voltage of the power supply port VDD. In another embodiment, the first switch tube S1 is a PMOS tube, the gate is connected to a fixed voltage source DVDD, the source is coupled to the second feedback path, the drain is coupled to the feedback signal port FB, and the output voltage of the fixed voltage source DVDD is less than the output voltage of the power supply port VDD.

The first feedback path comprises a second switch tube S2 and a second resistor R2, the second switch tube S2 and the second resistor R2 are sequentially coupled between a power supply port VDD and a feedback signal port FB, the feedback signal port FB is grounded through a third switch tube S3 and a sampling feedback circuit, when the first switch tube S1 is turned off, the second switch tube S2 and the third switch tube S3 are conducted, and the feedback signal port FB voltage is pulled up to the power supply port VDD voltage through the second resistor R2 and the second switch tube S2; when the first switch tube S1 is turned on, the second switch tube S2 is turned off. In one embodiment, the second switch tube S2 is a second field effect transistor having a gate connected to the digital power supply port DVDD, a source coupled to the feedback signal port FB through a second resistor R2, and a drain coupled to the power supply port VDD. In another embodiment, the second switch tube S2 is an NMOS tube, and has a gate connected to the digital power supply port DVDD, a source coupled to the feedback signal port FB through the second resistor R2, and a drain coupled to the power supply port VDD.

The second feedback path further includes a current mirror and a third resistor R3, wherein an input stage T0 of the current mirror is coupled to the first switch tube S1, and an output stage T1 is connected to a fixed voltage source DVDD through the third resistor R3 and is grounded through the third switch tube S3 and the sampling feedback circuit, and an output voltage of the fixed voltage source is smaller than an output voltage of the power supply port. In one embodiment, the third switch tube S3 is a third effect transistor having a gate coupled to the output stage T1 of the current mirror, a source coupled to the sampling feedback circuit, a drain coupled to the feedback signal port FB, and an input stage T0 of the current mirror coupled to the source of the first switch tube S1. In another embodiment, the third switch transistor S3 is an NMOS transistor, and has a gate coupled to the output stage T1 of the current mirror, a source coupled to the sampling feedback circuit, and a drain coupled to the feedback signal port FB.

In one embodiment, the sampling feedback circuit includes a fourth switch transistor S4 and a first resistor R1, which are in turn coupled between the source of the third switch transistor and ground.

In one embodiment, the fourth switch transistor S4 is a fourth field effect transistor with a gate connected to the modulation signal mode, a drain coupled to the source of the third switch transistor S3, and a source connected to ground through the first resistor R1.

According to another aspect of the present invention, a control method is provided for closed-loop feedback of different optical coupling connection architectures, a feedback path is respectively formed according to the on or off of a first switch tube S1 to perform sampling of an optical coupling feedback current, the first switch tube S1 is coupled to a feedback signal port FB, wherein a first feedback path is formed between the feedback signal port FB and a power supply port VDD when the first switch tube S1 is turned off; the feedback signal port FB forms a second feedback path based on the first switch tube S1 when the first switch tube S1 is turned on.

According to a third aspect of the present invention, a voltage conversion circuit includes an optical coupler and the above-mentioned control circuit, wherein a feedback end of the optical coupler is coupled to an output end of the voltage conversion circuit, and is configured to obtain a feedback signal of a voltage at the output end of the voltage conversion circuit; the receiving end of the optical coupler is coupled to the input end of the voltage conversion circuit through the control circuit and used for receiving a feedback signal of the feedback end of the optical coupler and feeding the feedback signal back to the input end of the voltage conversion circuit through the control circuit.

In an embodiment, the receiving end U1B of the optical coupler is coupled between the feedback signal port FB of the control circuit 2 and the ground reference port GND to form an optical coupler ground connection, as shown in fig. 6, a voltage of the signal feedback port FB is pulled up to VDD through the second resistor R2 and the second switching tube S2, a gate of the NMOS tube is connected to the fixed voltage source DDVD (6V), at this time, the voltage of the signal feedback port FB cannot exceed 6V, that is, the first switching tube S1 is closed, and then, corresponding current mirrors are all in a closed state, the gate voltage of the signal feedback port FB is connected to the third switching tube S3 in series, and the NMOS tube is opened to form an FB voltage feedback loop. The state corresponds to typical SSR Low-side optocoupler feedback application.

In another embodiment, the receiving end U1B of the optical coupler is coupled between the feedback signal port FB of the control circuit 2 and the ground reference port GND to form an optical coupler ground connection, as shown in fig. 6, the voltage of the signal feedback port FB is pulled up to VDD through the second resistor R2 and the NMOS transistor (i.e., S2 in the figure), the gate of the NMOS transistor is connected to the fixed voltage source DDVD (6V), at this time, the voltage of the signal feedback port FB cannot exceed 6V, i.e., the PMOS transistor (i.e., S1 in the figure) is turned off, and then the corresponding current mirrors are all in a turned off state, the gate voltage of the NMOS transistor (i.e., S3 in the figure) connected below the signal feedback port FB is raised, and the NMOS transistor is turned on to form an FB voltage.

In one embodiment, the receiving end U1B of the optical coupler is coupled between the power supply port VDD of the control circuit 2 and the feedback signal port FB to form an optical coupler floating connection, as shown in fig. 7, the voltage of the signal feedback port FB is clamped in a state of DVDD + Vth-pmos (the VDD voltage is set to be higher than the DVDD voltage), the pull-up resistor R2 inside the signal feedback port FB is turned off by the DVDD and the second switching tube S2, and the signal feedback port FB is in a voltage-clamped + optical coupler current regulation state. Meanwhile, the current mirrors mapped by the first switch tube S1 are in working states, and the working current of the current mirror in series under the third resistor (with the resistance value of 120k) is mapped by the working current of the first switch tube S1 to adjust the drain voltage; the drain voltage is finally fed back to the FB voltage division part through a third switching tube S3 in series under the signal feedback port FB, so that the conversion of the optocoupler current- > FB voltage is realized.

In another embodiment, the receiving end U1B of the optical coupler is coupled between the power supply port VDD of the control circuit 2 and the feedback signal port FB to form an optical coupler floating connection, as shown in fig. 7, the voltage of the signal feedback port FB is clamped in a state of DVDD + Vth-pmos (where VDD voltage is set higher than DVDD voltage), the pull-up resistor R2 inside the signal feedback port FB is turned off by the DVDD and NMOS transistor (i.e., S2 in the figure), and the signal feedback port FB is in a state of voltage clamping + optical coupler current regulation. Meanwhile, several current mirrors mapped by the PMOS transistor (i.e. S1 in the figure) are in an operating state, and the operating current of the series current mirror under the 120k resistor (i.e. R3 in the figure) is mapped by the operating current of the PMOS transistor (i.e. S1 in the figure) to adjust the drain voltage of the PMOS transistor; the drain voltage is finally fed back to the FB voltage division point through the NMOS (i.e., S3 in the figure) of the string under the signal feedback port FB, so that the conversion of the optocoupler current- > FB voltage is realized.

The voltage conversion circuit is applied to a power supply system to form the power supply system with high adaptability.

According to a fourth aspect of the present invention, in a control method for performing feedback based on an optocoupler, when the optocoupler is coupled between a first port and a second port of a control circuit, a first switch tube in the control circuit is turned off, and a first feedback path is formed in the control circuit; when the optical coupler is coupled between the second port and the third port of the control circuit, a first switch tube in the control circuit is conducted, and a second feedback path is formed in the control circuit.

In one embodiment, a control method based on optical coupling for feedback includes that when the optical coupling is coupled between a feedback signal port FB and a reference ground port GND of a control circuit, a first switching tube S1 in the control circuit is turned off, and a first feedback path is formed inside the control circuit between the feedback signal port FB and the reference ground port GND; when the optical coupler is coupled between the feedback signal port FB and the ground reference port GND of the control circuit, the first switch tube S1 in the control circuit is turned on, and a second feedback path is formed between the feedback signal port FB and the ground reference port GND in the control circuit.

Those skilled in the art should understand that the logic controls such as "high" and "low", "set" and "reset", "and gate" and "or gate", "non-inverting input" and "inverting input" in the logic controls referred to in the specification or the drawings may be exchanged or changed, and the subsequent logic controls may be adjusted to achieve the same functions or purposes as the above-mentioned embodiments.

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. The descriptions related to the effects or advantages in the specification may not be reflected in practical experimental examples due to uncertainty of specific condition parameters or influence of other factors, and the descriptions related to the effects or advantages are not used for limiting the scope of the invention. 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.