Control circuit with built-in double energy storage units

Abstract

The utility model provides a control circuit with double built-in energy storage units. The control circuit comprises a high-voltage power supply circuit, the input end of which is coupled with the input end of the power switch tube; the first power supply control circuit is coupled to the output end of the high-voltage power supply circuit; the first energy storage unit is coupled with the output end of the first power supply control circuit and the power supply input end of the logic control circuit; the second power supply control circuit is coupled with the high-voltage power supply circuit; and the second energy storage unit is coupled with the power input end of the driving circuit. According to the control circuit provided by the utility model, the two energy storage units are integrated in the semiconductor chip, so that the problem of mutual interference of high and low power supplies is eliminated or reduced, the reliability is improved, and the integration level and the power supply capability are improved.

Description

Technical Field

[0001] The utility model relates to the field of electronics, and specifically but not limited to, relates to a control circuit with built-in dual energy storage units. Background Art

[0002] In a switching power supply, to provide a stable operating power supply to the control chip, external capacitors are often used in conjunction with a power control circuit to stabilize the control chip's power supply at a certain value to ensure normal operation. With technological advancements, the integration of switching power supplies is becoming increasingly higher. To save costs and improve reliability, more peripheral components are being integrated into the chip itself, such as the power capacitors.

[0003] At the same time, the control chip usually requires two types of power supplies with large voltage differences. The first type of power supply is used to supply power to logic units and other lower voltages, and the other type of power supply is used to supply power to the power drive circuit. The power drive circuit requires a large amount of energy, and the power supply to the drive circuit can easily cause interference to the low-voltage unit, resulting in instability of the transient signal.

[0004] In view of this, it is necessary to provide a structure or power supply method to solve or optimize at least part of the above problems. Utility Model Content

[0005] In response to at least one or more problems in the background technology, the present invention proposes a control circuit for controlling a built-in dual energy storage unit of a power switch tube in a switching power supply, comprising: a logic control circuit, wherein the input end of the logic control circuit is coupled to the output voltage signal feedback end of the control circuit, and the output end of the logic control circuit provides a logic control signal; a drive circuit, wherein the input end of the drive circuit is coupled to the output end of the logic control circuit, and the output end of the drive circuit is coupled to the control end of the power switch tube; a high-voltage power supply circuit, wherein the input end of the high-voltage power supply circuit is coupled to the line voltage end and the input end of the power switch tube; a first power supply control circuit, wherein the input end of the first power supply control circuit is coupled to the output end of the high-voltage power supply circuit; a first energy storage unit, wherein the first end of the first energy storage unit is coupled to the output end of the first power supply control circuit and the power input end of the logic control circuit, and the second end of the first energy storage unit is coupled to a reference ground; a second power supply control circuit, coupled to the high-voltage power supply circuit; a second energy storage unit, wherein the first end of the second energy storage unit is coupled to the power input end of the drive circuit, the second power supply control circuit is used to control a second supply voltage on the first end of the second energy storage unit, and the second end of the second energy storage unit is coupled to the reference ground.

[0006] Optionally, the high-voltage power supply circuit includes a junction field-effect transistor (JFET), the power switch tube includes a metal oxide semiconductor field-effect transistor (MOSFET), the drain of the JFET is coupled to the drain of the MOSFET, and the gate of the MOSFET is connected to the output end of the drive circuit.

[0007] Optionally, the high-voltage power supply circuit includes a first high-voltage device and a second high-voltage device, wherein the input end of the first high-voltage device and the input end of the second high-voltage device are coupled to the line voltage end, the output end of the first high-voltage device is coupled to the input end of the first power supply control circuit, and the second high-voltage device is coupled to the second power supply control circuit and the second energy storage unit.

[0008] Optionally, the output terminal of the second power supply control circuit is coupled to the control terminal of the high-voltage power supply circuit.

[0009] Optionally, the input end of the second power supply control circuit is coupled to the output end of the high-voltage power supply circuit, and the output end of the second power supply control circuit is coupled to the first end of the second energy storage unit.

[0010] Optionally, the control circuit further includes a selection switch, a first end of the selection switch is coupled to the output voltage signal feedback end, and a second end of the selection switch is coupled to the output end of the high-voltage power supply circuit.

[0011] Optionally, the input end of the second power supply control circuit is coupled to the first end of the second energy storage unit and the output end of the high-voltage power supply circuit, and the output end of the second power supply control circuit is coupled to the power input end of the drive circuit.

[0012] Optionally, the first power supply control circuit includes a linear voltage stabilization circuit or a switch control conversion circuit.

[0013] The control circuit with built-in dual energy storage units proposed in the utility model eliminates or reduces the problem of mutual interference between high and low power supplies, improves reliability, and simultaneously improves integration and power supply capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and, together with the description, to explain the embodiments of the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 Shows a block diagram of a control circuit according to an embodiment of the present utility model;

[0016] Figure 2 Shown is a control circuit according to a specific embodiment of the utility model;

[0017] Figure 3 shows a control circuit according to another embodiment of the present utility model;

[0018] Figure 4 Shows a schematic diagram of a control circuit block diagram according to an embodiment of the present utility model;

[0019] Figure 5 A switching power supply system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0020] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0021] The description in this section focuses on several typical embodiments only. The present invention is not limited to the scope of the embodiments described. Combinations of different embodiments, replacement of certain technical features in different embodiments, and replacement of certain technical features in the embodiments with the same or similar prior art methods are also within the scope of the present invention.

[0022] "Coupled" or "connected" in this specification encompasses both direct and indirect connections. An indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium like a conductor, which may contain parasitic inductance or capacitance, or a connection through an intermediate circuit or component as described in the embodiments of this specification. An indirect connection may also include a connection through other active or passive devices that achieve the same or similar functions, such as a connection through circuits or components such as switches, signal amplifiers, and follower circuits. "Multiple" or "many" refers to two or more.

[0023] Figure 1A control circuit 100 according to an embodiment of the present invention is shown. The control circuit 100 is used to control a power switch 16 in a switching power supply. The control circuit 100 includes two power supplies, providing two independent power supplies VDD and VDDG, which are used to power the logic control circuit 13 and the drive circuit 15, respectively. The first power supply voltage VDD for the logic control circuit 13 has a lower voltage value, while the second power supply voltage VDDG for the power drive circuit 15 has a higher voltage value and a larger current output capacity. The two power supplies each have independent energy storage units C1 and C2, so that the power supply VDDG does not affect the power supply capacity of the logic control circuit 13 when outputting high current. Specifically, the control circuit 100 includes a high-voltage power supply circuit 11, a first power supply control circuit 12, a first energy storage unit C1, a logic control circuit 13, a second power supply control circuit 14, a second energy storage unit C2, and a drive circuit 15. In one embodiment, the control circuit 100 is fabricated on the same semiconductor substrate and integrated into a single control chip. The input of the logic control circuit 13 receives a feedback signal FB representing the output signal of the switching power supply, and the output of the logic control circuit 13 provides a logic control signal CTL. The feedback signal FB may represent the output voltage Vout of the switching power supply, or may include a feedback signal representing the output current. The input of the driver circuit 15 is coupled to the output of the logic control circuit 13, and the output of the driver circuit 15 is coupled to the control terminal of the power switch 16. Under the control of the logic control circuit CTL, the driver circuit 15 is configured to amplify the logic control signal CTL using the second supply voltage VDDG and drive the power switch 16 to control the on and off states of the power switch 16 to adjust the corresponding output signal of the switching power supply. The input of the high-voltage power supply circuit 11 is coupled to the line voltage terminal HV and the input of the power switch 16. When on, the high-voltage power supply circuit 11 is configured to draw energy from the line voltage terminal HV to provide power to the control circuit 100. In one embodiment, the line voltage HV is the voltage obtained by full-wave rectification and filtering of the AC mains power supply. The input terminal of the power switch tube 16 is coupled to the line voltage terminal. When the power switch tube 16 is turned on, the switching power supply obtains energy from the line voltage terminal HV to power the load at the back end of the switching power supply, and stores the energy in devices such as the inductor and capacitor. When the power switch tube 16 is turned off, the energy stored in the inductor and capacitor continues to power the load. Preferably, the switching power supply includes a step-down (Buck) circuit, the input terminal of the power switch tube 16 is coupled to the line voltage terminal HV, the output terminal of the power switch tube 16 is coupled to the first terminal of the rectifier tube and the first terminal of the inductor, the second terminal of the rectifier tube is coupled to the system ground, and the second terminal of the inductor is coupled to the output capacitor and the load.When the power switch tube 16 is turned off or is shallowly conductive, the high-voltage power supply circuit 11 is turned on and is used to supply power to the first energy storage unit C1 and / or the logic control circuit 13 under the control of the first power supply control circuit 12, and to supply power to the second energy storage unit C2 and / or the drive circuit 15 under the control of the second power supply control circuit 14. Under the control of the first power supply control circuit 12, the first energy storage unit C1 obtains electrical energy from the output end of the high-voltage power supply circuit 11 and provides a first power supply voltage VDD for powering the logic control circuit 13. Preferably, the input end of the first power supply control circuit 12 is coupled to the output end of the high-voltage power supply circuit 11, the first end of the first energy storage unit C1 is coupled to the output end of the first power supply control circuit 12 and the power input end of the logic control circuit 13, the second end of the first energy storage unit C1 is coupled to the reference ground, and the first power supply voltage VDD on the first end of the first energy storage unit C1 is used to power the logic control circuit 13. The first power supply control circuit 12 isolates the first energy storage unit C1 from the high-voltage power supply unit 11 and controls the voltage level of the first power supply voltage VDD output by the first energy storage unit C1, thereby providing a stable power supply of suitable amplitude for the logic control circuit. A second power supply providing the second power supply voltage VDDG for the drive circuit 15 includes a second energy storage unit C2 and a second power supply control circuit 14. The second power supply control circuit 14 is coupled to the high-voltage power supply circuit 11. Under the control of the second power supply control circuit 14, the second energy storage unit C2 draws power from the output terminal of the high-voltage power supply circuit 11. A first terminal of the second energy storage unit C2 provides a stable second power supply voltage VDDG that is higher than the first power supply voltage VDD for powering the drive circuit 15. The second terminal of the second energy storage unit C2 is coupled to the reference ground. In this way, the second power supply voltage VDDG for powering the drive circuit 15 and the first power supply voltage VDD for powering the logic control circuit 13 each have independent energy storage units and control circuits. Their power supplies are independent of each other, making the logic control circuit less susceptible to signal fluctuations, and further enhancing system reliability. Furthermore, distributing the energy in one energy storage unit across two energy storage units can reduce the requirements for individual capacitor values, facilitate integration into a control chip, and improve overall power supply capacity. In one embodiment, the first energy storage unit C1 and the second energy storage unit C2 each include a capacitor, wherein the capacitance of the second energy storage unit C2 is greater than that of the first energy storage unit C1.

[0024] Figure 2A control circuit 200 according to a specific embodiment of the present invention is shown. In this embodiment, the high-voltage power supply circuit 21 includes a junction field-effect transistor (JFET), and the power switch 26 includes a metal-oxide-semiconductor field-effect transistor (MOSFET). The drain of the JFET is coupled to the drain of the MOSFET, the source of the JFET is coupled to the input of the first power supply control circuit 22 and the second energy storage unit C2, and the gate of the MOSFET is connected to the output of the drive circuit 25. The output of the first power supply control circuit 22 is coupled to the first terminal of the first energy storage unit C1 and the power input of the logic control circuit 23, for powering the logic control circuit 23. The second terminal of the first energy storage unit C1 is coupled to the reference ground GND. In the illustrated embodiment, the reference ground GND is coupled to the second terminal of the current sense resistor Rcs, the first terminal of which is coupled to the source of the power switch 26. In one embodiment, the reference ground GND and the system ground of the switching power supply output are not shared. In another embodiment, the reference ground GND and the system ground of the switching power supply output are shared. In one embodiment, a resistor may be provided between the energy storage unit and the reference ground GND. In this embodiment, the first power supply control circuit 22 includes a linear voltage regulator (LDO) circuit coupled between the output terminal (source of the JFET) of the high-voltage power supply circuit 21 and the capacitor C1. Of course, the first power supply control circuit may also include other types of circuits, such as a switch control conversion circuit (Buck circuit, etc.), which is used to step down the voltage at the output terminal of the high-voltage power supply circuit 21 into a stable voltage, providing a stable, lower first power supply voltage VDD for the power input terminal of the logic control circuit 23. In the illustrated embodiment, the first terminal of the second energy storage unit C2 is directly coupled to the output terminal of the high-voltage power supply circuit 21, and the second terminal of the second energy storage unit C2 is grounded. The output terminal of the second power supply control circuit 24 is directly coupled to the control terminal of the high-voltage power supply circuit 21, and is used to control the on and off states of the high-voltage power supply circuit 21, thereby controlling the output terminal of the high-voltage power supply circuit 21 to provide a stable second power supply voltage VDDG for powering the drive circuit 25. In one embodiment, the second power supply control circuit 24 controls the on / off state of the JFET 21 based on the second power supply voltage VDDG and the logic control signal CTL. When the logic control signal CTL instructs the power switch 26 to turn off and the second power supply voltage VDDG is lower than a preset value, the second power supply control circuit 24 controls the JFET 21 to turn on. In another embodiment, the second power supply control circuit 24 controls the on / off state of the high-voltage power supply circuit 21 based on the second power supply voltage VDDG and the line voltage terminal HV.Optionally, the second power supply control circuit 24 includes a first power supply comparison circuit and a second power supply comparison circuit, wherein the input terminals of the first power supply comparison circuit are respectively coupled to the line voltage terminal HV and a threshold signal, and the input terminals of the second power supply comparison circuit are respectively coupled to the first terminal of the second energy storage unit C2 and the power supply threshold signal. When the line voltage terminal HV is greater than a threshold and the second power supply voltage VDDG is lower than a preset value, the second power supply control circuit 24 controls the high-voltage power supply circuit 21 to conduct, thereby supplying power to the second energy storage unit C2. When the line voltage terminal HV is lower than the threshold or the second power supply voltage VDDG is higher than the corresponding preset value, the second power supply control circuit 24 controls the high-voltage power supply circuit 21 to shut down, thereby enabling the second energy storage unit C2 to supply power to the drive circuit 25. In the illustrated embodiment, the logic control circuit 23 receives feedback signals FB and CS representing the output signal of the switching power supply and provides a logic signal CTL. Signal FB is an output voltage feedback signal representing the output voltage of the switching power supply, and signal CS is a current feedback signal representing the current flowing through the power switch 26. Specifically, the logic control circuit 23 may include a first comparison circuit 231 , a second comparison circuit 232 and a trigger circuit 233 . In the illustrated embodiment, the two input terminals of the first comparison circuit 231 are respectively coupled to the output voltage signal feedback terminal FB and the output voltage reference signal Vref. The first comparison circuit 231 is configured to compare the feedback signal FB representing the output voltage of the switching power supply with the output voltage reference signal Vref. The output terminal of the first comparison circuit 231 is coupled to the set input terminal of the trigger circuit 233. The two input terminals of the second comparison circuit 232 are respectively coupled to the current sampling terminal CS and the peak reference signal Vipk. The output terminal of the second comparison circuit is coupled to the reset terminal of the trigger circuit 233. When the output voltage is lower than a preset value, the first comparison circuit 231 outputs a high level, setting the trigger circuit 233 and setting the logic control signal CTL to a high level. The driver circuit 25, powered by the second supply voltage VDDG, amplifies the high level signal CTL to turn on the power switch 26. When the current flowing through the power switch 26 rises to a peak threshold, the second comparison circuit 232 outputs a high level, resetting the trigger circuit 233 and setting the logic control signal CTL to a low level to turn off the power switch 26. In other embodiments, the logic control circuit may have other structures and control methods. Preferably, the control circuit 200 is fabricated on the same semiconductor substrate as a semiconductor integrated circuit chip, such as a silicon substrate, that is, integrated into a semiconductor chip. The term "integrated" here does not include package integration through electronic packaging processes. In the control circuit of the above embodiment, since the energy storage devices C1 and C2 are integrated into the semiconductor chip, no capacitor devices are provided, either within the electronic package or outside the electronic package, thereby simplifying the external circuit.

[0025] Figure 3 FIG. 3 shows a control circuit 300 according to another embodiment of the present invention. Figure 2 Compared to the control circuit 200, the second power supply control circuit 34 is located between the output terminal of the high-voltage power supply circuit 31 and the second energy storage unit C2. It is used to isolate the output terminal of the high-voltage power supply circuit 31 from the second energy storage unit C2 and convert the output voltage of the high-voltage power supply circuit 31 to the second power supply voltage VDDG, which is then stored in the second energy storage unit C2 and used to power the drive circuit. In the illustrated embodiment, the second power supply control circuit 34 includes a low-voltage difference voltage regulator circuit for controlling the second energy storage unit C2 to have a stable second power supply voltage VDDG. The output terminal of the second power supply control circuit 34 is coupled to the first terminal of the second energy storage unit C2, and the second terminal of the second energy storage unit C2 is coupled to the reference ground GND.

[0026] In another embodiment, the second energy storage unit C2 is coupled to the output terminal of the high-voltage power supply circuit, the input terminal of the second power supply control circuit is coupled to the first terminal of the second energy storage unit and the output terminal of the high-voltage power supply circuit, the second terminal of the second energy storage unit is coupled to the reference ground, and the output terminal of the second power supply control circuit provides a second supply voltage for powering the drive circuit. The second power supply control circuit may include a low voltage dropout linear voltage regulator circuit.

[0027] Figure 4 FIG. 4 is a block diagram of a control circuit 400 according to an embodiment of the present invention. Figure 1 Compared with the control circuit 100, the high-voltage power supply circuit in the control circuit 400 includes a first high-voltage device 411 and a second high-voltage device 412. The input end of the first high-voltage device 411 and the input end of the second high-voltage device 412 are coupled to the line voltage end HV, the output end of the first high-voltage device 411 is coupled to the input end of the first power supply control circuit 42, and the output end of the second high-voltage device 412 is coupled to the second power supply control circuit 44 and the second energy storage unit C2. The coupling method of the second high-voltage device 412, the second power supply control circuit 44 and the second energy storage unit C2 can be a combination of Figure 1-Figure 3 The coupling method of the high-voltage power supply circuit, the second power supply control circuit, and the second energy storage unit C2 in any manner described above. In one embodiment, the output end of the second power supply control circuit 44 can be directly coupled to the control end of the second high-voltage device 412 to control the voltage of the output end of the second high-voltage device 412, and the output end of the second high-voltage device 412 is coupled to the second energy storage unit C2 to provide a stable second supply voltage VDDG.

[0028] Figure 5A switching power supply system 500 according to an embodiment of the present invention is shown. In this embodiment, the output of the high-voltage power supply circuit 511 is coupled to the output voltage signal feedback terminal FB of the control circuit 50 via a selection switch K. The output voltage Vout provides both a feedback signal and power supply to the control circuit 50 via a unidirectional conductive device D1. The switching power supply system 500 includes a control circuit 50, a step-down (Buck) circuit 51, and a unidirectional conductive device D1. The output of the switching power supply provides an output voltage Vout for supplying power to a load. The unidirectional conductive device D1 is coupled between the output of the switching power supply and the output voltage signal feedback terminal FB. The control circuit 50 includes a selection switch K, wherein a first terminal of the selection switch K is coupled to the output voltage signal feedback terminal FB, and a second terminal of the selection switch K is coupled to the output of the high-voltage power supply circuit 511. The selection switch K couples the unidirectional conductive device D1 between the output of the switching power supply and the output of the high-voltage power supply circuit 511. In the illustrated embodiment, the unidirectional conducting device D1 comprises a diode. The input terminal of the unidirectional conducting device D1, i.e., the anode of the diode D1, is coupled to the output terminal of the switching power supply. The output terminal of the unidirectional conducting device D1, i.e., the cathode of the diode D1, is coupled to the output voltage signal feedback terminal FB of the control circuit 50. This allows current flowing through the unidirectional conducting device D1 to flow from the output terminal of the switching power supply to the output terminal of the high-voltage power supply circuit 511. When the line voltage HV falls below a threshold or the power switch Q is turned off, the high-voltage power supply circuit 511 is turned off, and the output terminal of the switching power supply selectively supplies power to the control circuit 50 based on the voltage values ​​of the first supply voltage VDD and the second supply voltage VDDG.

[0029] The description and application of the present invention here are illustrative and are not intended to limit the scope of the present invention to the above-mentioned embodiments. The relevant descriptions of the effects or advantages involved in the specification may not be reflected in the actual experimental examples due to the uncertainty of specific condition parameters or other factors, and the relevant descriptions of the effects or advantages are not used to limit the scope of the utility model. Variations and changes to the embodiments disclosed here are possible, and the replacement of the embodiments and various equivalent components are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that, without departing from the spirit or essential characteristics of the present invention, the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts. Without departing from the scope and spirit of the present invention, other variations and changes can be made to the embodiments disclosed here.

Claims

1. A control circuit with a built-in dual energy storage unit for controlling a power switch in a switching power supply, the control circuit comprising: a logic control circuit, wherein an input terminal of the logic control circuit is coupled to an output voltage signal feedback terminal of the control circuit, and an output terminal of the logic control circuit provides a logic control signal; A driving circuit, wherein an input end of the driving circuit is coupled to an output end of the logic control circuit, and an output end of the driving circuit is coupled to a control end of the power switch tube; Characterized in that the control circuit further comprises: A high-voltage power supply circuit, wherein an input end of the high-voltage power supply circuit is coupled to a voltage terminal and an input end of a power switch tube; a first power supply control circuit, wherein an input terminal of the first power supply control circuit is coupled to an output terminal of the high-voltage power supply circuit; a first energy storage unit, wherein a first end of the first energy storage unit is coupled to the output end of the first power supply control circuit and the power input end of the logic control circuit, and a second end of the first energy storage unit is coupled to a reference ground; a second power supply control circuit coupled to the high-voltage power supply circuit; and The second energy storage unit has a first end coupled to the power input end of the driving circuit, a second power supply control circuit is used to control the second power supply voltage on the first end of the second energy storage unit, and a second end of the second energy storage unit is coupled to the reference ground.

2. The control circuit with built-in dual energy storage units according to claim 1, characterized in that: The high-voltage power supply circuit includes a junction field effect transistor (JFET), the power switch tube includes a metal oxide semiconductor field effect transistor (MOSFET), the drain of the JFET is coupled to the drain of the MOSFET, and the gate of the MOSFET is connected to the output end of the driving circuit.

3. The control circuit with built-in dual energy storage units according to claim 1, characterized in that: The high-voltage power supply circuit includes a first high-voltage device and a second high-voltage device, wherein the input end of the first high-voltage device and the input end of the second high-voltage device are coupled to the line voltage end, the output end of the first high-voltage device is coupled to the input end of the first power supply control circuit, and the second high-voltage device is coupled to the second power supply control circuit and the second energy storage unit.

4. The control circuit with built-in dual energy storage units according to claim 1, characterized in that: The output terminal of the second power supply control circuit is coupled to the control terminal of the high-voltage power supply circuit.

5. The control circuit with built-in dual energy storage units according to claim 1, characterized in that: An input terminal of the second power supply control circuit is coupled to an output terminal of the high-voltage power supply circuit, and an output terminal of the second power supply control circuit is coupled to a first terminal of the second energy storage unit.

6. The control circuit with built-in dual energy storage units according to claim 5, characterized in that: The control circuit further includes a selection switch, a first end of the selection switch is coupled to the output voltage signal feedback end, and a second end of the selection switch is coupled to the output end of the high-voltage power supply circuit.

7. The control circuit with built-in dual energy storage units according to claim 1, characterized in that: The input end of the second power supply control circuit is coupled to the first end of the second energy storage unit and the output end of the high-voltage power supply circuit, and the output end of the second power supply control circuit is coupled to the power input end of the driving circuit.

8. The control circuit with built-in dual energy storage units according to claim 1, wherein: The first power supply control circuit includes a linear voltage stabilization circuit or a switch control conversion circuit.

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