TW201345115A - Control circuit for regulator and related control method - Google Patents

Abstract

A control circuit for use in a regulator is disclosed. The regulator comprises an inductor. The control circuit comprises a power switch; a voltage input terminal for coupling with a terminal of the inductor; a control signal generator, coupled with a control terminal of the power switch, for controlling the operation of the power switch; a first transistor having a first terminal coupled with the voltage input terminal and a first terminal of the power switch; a reference voltage controller for controlling a reference voltage; a comparator, coupled with the reference voltage controller, a control terminal of the first transistor, and a feedback signal, for comparing the reference voltage and the feedback signal to switch the operations of the first transistor to control an operating voltage of the control signal generator; and a feedback signal, coupled with the comparator, for generating the feedback signal according to the operating voltage.

Description

Control circuit for regulator and related control method

The invention relates to a switching regulator, in particular to a control circuit for a switching regulator and a related control method.

Switching regulators must rely on the control of a control signal generator (such as a PWM signal generator) in the control circuit to produce a stable output voltage. Therefore, the control circuit plays a role in the operation of the switching regulator. Very important role.

In the control circuit of the switching regulator, an appropriate starting circuit needs to be set to start the operation of the control signal generator. However, the startup circuit in the conventional control circuit needs to receive an appropriate startup voltage from outside the control circuit to start the control signal generator inside the control circuit. Therefore, it is necessary to provide a dedicated signal pin for the control circuit for the startup circuit to receive the startup voltage.

When the startup circuit starts the control signal generator in the control circuit, the startup circuit stops operating and there is no need to receive the startup voltage from outside the control circuit. Therefore, the dedicated pin on the control circuit that is used to receive the startup voltage will remain idle, resulting in wasted use of the pin. In particular, integrated circuit products often require a larger package because of the larger number of pins, so that the area of the die is often much smaller than the area of the package, which not only wastes materials but also causes environmental problems, and also causes The volume of integrated circuit products cannot be effectively reduced. Therefore, in order to make the control circuit of the switching regulator select a smaller package size, it is obviously necessary to further reduce the number of pins of the control circuit.

In view of this, how to effectively reduce the number of pins of the control circuit of the voltage regulator to effectively reduce the area and cost of the circuit chip is a problem to be solved in the industry.

The present specification provides an embodiment of a control circuit for a voltage regulator, the voltage regulator includes an inductor, the control circuit includes: a power switch; a voltage input terminal for coupling one end of the inductor; a control signal generator coupled to the control end of the power switch for controlling the operation of the power switch; a first transistor having a first end coupled to the voltage input terminal and the first end of the power switch And the second end of the first transistor is coupled to the control signal generator; a reference voltage controller is configured to control a reference voltage; a comparator is coupled to the reference voltage controller, the first a control end of the crystal, and a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to control an operating voltage of the control signal generator; and a feedback The circuit is coupled to the comparator for generating the feedback signal according to the operating voltage.

The present specification further provides an embodiment of a control circuit for a voltage regulator, the voltage regulator includes a power switch and an inductor, the control circuit includes: a voltage input terminal for coupling one end of the inductor; a control signal generator for coupling the control end of the power switch to control the operation of the power switch; a first transistor having a first end coupled to the voltage input end, and the first transistor The second end is coupled to the control signal generator; a reference voltage controller is configured to control a reference voltage; a comparator is coupled to the reference voltage controller, the control end of the first transistor, and a back And a signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to control an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator And for generating the feedback signal according to the operating voltage.

The present specification further provides an embodiment of a control circuit for a voltage regulator, the voltage regulator includes an inductor and a diode, the control circuit includes: a power switch, the second end of which is coupled to The inductor and the diode; a voltage input terminal for coupling the input voltage of the voltage regulator; a control signal generator coupled to the control terminal of the power switch for controlling the operation of the power switch; a first transistor, the first end of which is coupled to the voltage input end and the first end of the power switch, and the second end of the first transistor is coupled to the control signal generator; a reference voltage controller For controlling a reference voltage, a comparator coupled to the reference voltage controller, the control end of the first transistor, and a feedback signal for comparing the reference voltage and the feedback signal to switch the The operation of the first transistor to control the magnitude of an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator for generating the feedback signal according to the operating voltage.

The present specification further provides an embodiment of a control circuit for a voltage regulator, the voltage regulator includes a power switch and an inductor, the control circuit includes: a voltage input terminal for coupling the voltage regulator Input voltage; a control signal generator for coupling the control end of the power switch to control the operation of the power switch; a first transistor having a first end coupled to the voltage input end, and the first a second end of the transistor is coupled to the control signal generator; a reference voltage controller is configured to control a reference voltage; a comparator is coupled to the reference voltage controller, the control end of the first transistor, And a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to control an operating voltage of the control signal generator; and a feedback circuit coupled to the The comparator is configured to generate the feedback signal according to the operating voltage.

One of the advantages of the above control circuit is that the voltage at the voltage input can be used as the starting voltage of the control signal generator, which saves the signal pins required for the control circuit.

Another advantage of the above control circuit is that after the control signal generator is activated, the control circuit can operate normally without relying on the bias voltage provided by other external bias circuits. Therefore, there is no need to provide an additional bias coil in the voltage regulator, which can reduce the complexity of the circuit design and the circuit cost.

The present specification further provides a method for controlling a voltage regulator, the voltage regulator comprising an inductor and a power switch, the method comprising: providing a voltage input terminal for coupling one end of the inductor; providing a control signal generation The first end of the first transistor is coupled to the voltage input terminal, and the second end of the first transistor is coupled to the control terminal of the power switch for controlling the operation of the power switch. Coupled with the control signal generator; providing a reference voltage; comparing the reference voltage and a feedback signal to switch the operation of the first transistor to control the magnitude of an operating voltage of the control signal generator; The operating voltage produces the feedback signal.

Other advantages of the invention will be explained in more detail by the following description and the accompanying drawings.

Embodiments of the present invention will be described below in conjunction with the associated drawings. In the figures, the same reference numerals are used to refer to the same or similar elements or process steps.

When plotting patterns, the scale of certain signals and the relative proportions between the signals are adjusted so that the content of the schema can be clearly expressed. In addition, the shape of some signals will be simplified to facilitate the drawing. Accordingly, the shapes and relative proportions of the various signals illustrated in the drawings are not intended to limit the scope of the invention unless otherwise specified by the applicant.

Certain terms are used throughout the description and subsequent claims to refer to particular elements. Those of ordinary skill in the art should understand that the same elements may be referred to by different nouns. This specification and subsequent claims do not use the difference in name as a means of distinguishing between components, but rather as a basis for distinguishing between functional differences of components. The word "contains" mentioned in the entire specification and subsequent claims is an open term and should be interpreted as "including but not limited to...". In addition, the term "coupled" is used herein to include any direct and indirect means of attachment. Therefore, if a first component is coupled to a second component, the first component can be directly connected to the second component (including a signal connection through electrical connection or wireless transmission, optical transmission, etc.), or Electrically or signally connected to the second component indirectly through other components or connections.

The description of "and/or" as used herein includes any combination of one or more of the listed items. In addition, the terms of any singular are intended to include the meaning of the plural, unless otherwise specified in the specification.

1 is a simplified functional block diagram of a flyback regulator 100 in accordance with an embodiment of the present invention. The flyback regulator 100 includes a bridge rectifier 110, an inductor 112, a feedback circuit 114, a control circuit 120, and other circuit components. The bridge rectifier 110 is for rectifying the AC voltage Vac supplied from the AC power source into a DC input voltage Vin. The control circuit 120 is used to control the operation of the flyback regulator 100 to cause the flyback regulator 100 to convert the input voltage Vin into a stable output voltage Vout for use by the downstream load. The control circuit 120 includes a voltage input terminal 121, a power switch 122, a control signal generator 123, a first transistor 124, a reference voltage controller 125, a comparator 126, a first feedback circuit 127, a diode 128, and a limit. Current limiter 129. In the embodiment of FIG. 1, the power switch 122 of the flyback regulator 100 is integrated in the control circuit 120.

The voltage input terminal 121 is used to couple one end (eg, a current output terminal) of the inductor 112 in the flyback regulator 100, and the voltage on the voltage input terminal 121 is represented by Vd. In this embodiment, the first end of the power switch 122 is coupled to the voltage input terminal 121, and the second end of the power switch 122 is coupled to a preset potential (eg, a ground terminal). Therefore, in the present embodiment, the voltage Vd at the voltage input terminal 121 is the voltage across the power switch 122. The control signal generator 123 is used to couple the power switch 122 to control the operation of the power switch 122 such that the flyback regulator 100 produces the desired output voltage Vout. In practice, the control signal generator 123 can be implemented with a PWM signal generator. Further, an appropriate driving circuit may be provided in the control signal generator 123 or an appropriate driving circuit may be provided between the control signal generator 123 and the power switch 122.

The first end of the transistor 124 is coupled to the voltage input terminal 121, and the second end of the transistor 124 is coupled to the control signal generator 123. The reference voltage controller 125 is for providing and adjusting the reference voltage Vref. The comparator 126 is coupled to the reference voltage controller 125, the control terminal of the transistor 124, and the first feedback signal Vf for comparing the reference voltage Vref and the feedback signal Vf to switch the operation of the transistor 124, thereby controlling the control. The magnitude of the operating voltage Vcc of the signal generator 123. The feedback circuit 127 is coupled to the comparator 126 for generating the first feedback signal Vf according to the operating voltage Vcc. As shown in FIG. 1, the feedback circuit 127 can divide the operating voltage Vcc with a simple resistor for generating a feedback signal Vf proportional to the operating voltage Vcc. In other embodiments, the feedback circuit 127 can also be implemented with other suitable components or circuit architectures.

The diode 128 can be disposed on the signal path between the voltage input terminal 121 and the feedback circuit 127 for preventing leakage current at the voltage input terminal 121. The current limiter 129 can be disposed on the signal path between the voltage input terminal 121 and the feedback circuit 127 for limiting the magnitude of the current flowing through the signal path, thereby protecting the transistor 124. For example, in the embodiment of FIG. 1, the current limiter 129 is disposed between the second end of the transistor 124 and the feedback circuit 127, and the diode 128 is disposed on the current limiter 129 and the feedback circuit 127. between. In other embodiments, the diode 128 can also be placed in the front stage of the current limiter 129. In addition, the diode 128 and/or the current limiter 129 may be disposed between the voltage input terminal 121 and the first end of the transistor 124.

In the control circuit 120, the transistor 124, the reference voltage controller 125, the comparator 126, the feedback circuit 127, the diode 128, and the current limiter 129 can operate in cooperation as a starting circuit of the control signal generator 123. The manner in which the control circuit 120 activates the control signal generator 123 and the subsequent mode of operation will be further described below in conjunction with FIG.

2 is a simplified timing diagram of signals generated by an operational embodiment of the control circuit 120 of FIG. 1. As shown in FIG. 2, when the flyback regulator 100 is energized, since the current of the inductor 112 gradually rises, the voltage Vd at the voltage input terminal 121 (that is, the voltage across the power switch 122) gradually rises to The input voltage Vin of the regulator 110 is close to or the same. Before the control signal generator 123 is activated, the transistor 124 will be in a turn on state, and the reference voltage controller 125 sets the reference voltage Vref to the first level TH1 such that the operating voltage Vcc follows the voltage input terminal 121. The upper voltage Vd gradually rises to the first predetermined voltage value V1. In the present embodiment, the predetermined voltage value V1 is higher than the normal operating voltage required by the control signal generator 123 to ensure that the control signal generator 123 can obtain a sufficiently high operating voltage. When the operating voltage Vcc reaches the predetermined voltage value V1 at time T1, the comparator 126 turns off the transistor 124 so that the operating voltage Vcc does not follow the voltage Vd at the voltage input terminal 121 and continues to rise.

When the operating voltage Vcc reaches a level sufficient to activate the control signal generator 123, for example, near time T1, the control signal generator 123 starts to operate. In operation, the control signal generator 123 generates a control signal CS according to the second feedback signal FB generated by the second feedback circuit 114 in the voltage regulator 110 to control the power switch 122. The control signal CS alternately switches between a high potential and a low potential to alternately turn on the power switch 122 and turn off the power switch 122.

As previously mentioned, when the operating voltage Vcc reaches a predetermined voltage value V1, that is, at time T1, the comparator 126 turns off the transistor 124. At this time, the reference voltage controller 125 also lowers the reference voltage Vref to the second level TH2 such that the operating voltage Vcc gradually decreases to the second predetermined voltage value V2 as the current consumption of the circuit such as the control signal generator 123. After the operating voltage Vcc drops to the second predetermined voltage value V2 at time T2, the comparator 126 compares the reference voltage Vref with the feedback signal Vf to switch the operation of the transistor 124, thereby controlling the operating voltage Vcc of the control signal generator 123. The size is such that the operating voltage Vcc is maintained in the vicinity of the predetermined voltage value V2.

In other words, after the control signal generator 123 is activated, the transistor 124, the reference voltage controller 125, the comparator 126, the feedback circuit 127, the diode 128, and the current limiter 129 continue to operate to function as the control circuit 120. The role of the internal regulator. In this way, after the control signal generator 123 is activated, the control circuit 120 can operate normally without relying on the bias voltage provided by other external bias coils. Therefore, no additional setting is required in the flyback regulator 100. By biasing the coil, the complexity and overall cost of the flyback regulator 100 in circuit design can be reduced.

In practice, the transistor 124 in the control circuit 120 can be implemented by a depleted metal oxide half field effect transistor, or can be implemented by a transistor of other architecture. In addition, the operating voltage Vcc can also be used as the operating voltage of other components in the control circuit 120.

As can be seen from the foregoing description, the voltage Vd at the voltage input terminal 121 not only determines the voltage across the power switch 122, but also serves as the starting voltage of the control signal generator 123. In other words, the voltage input terminal 121 is shared by the power switch 122 and the start-up circuit of the control signal generator 123. Therefore, the control circuit 120 does not need to provide an additional startup voltage pin for the startup circuit of the control signal generator 123, so that the number of circuit pins can be reduced.

In practice, the current limiter 129 in the control circuit 120 can be implemented by a resistor, a junction field correction transistor (JFET), or a depleted galvanic half field effect transistor, or other components with limited current characteristics or Device implementation. In some embodiments, diode 128 and/or current limiter 129 may be omitted to save circuit area of control circuit 120.

In the foregoing flyback regulator 100, an external capacitor 130 can be added outside the control circuit 120, and the capacitor 130 is coupled to the operating voltage Vcc in the control circuit 120 to reduce the noise of the operating voltage Vcc. The operating voltage Vcc is made more stable.

In addition, a bias coil 116 may be disposed in the flyback regulator 100, and the bias coil 116 is coupled to the operating voltage Vcc in the control circuit 120 to enable the user of the flyback regulator 100 or The manufacturer can use the bias voltage supplied from the bias coil 116 to set the magnitude of the operating voltage Vcc of the control signal generator 123.

FIG. 3 is a simplified functional block diagram of a flyback regulator 300 according to another embodiment of the present invention. The flyback regulator 300 is similar to the flyback regulator 100 described above, with the difference that the control circuit 120 in the flyback regulator 300 further includes a second transistor 324. The first end of the transistor 324 is coupled to the voltage input terminal 121, the second end is coupled to the power switch 122, and the control end is coupled to the control signal generator 123. In practice, the control signal generator 123 can synchronously switch the power switch 122 and the transistor 324 in the same control manner.

In the embodiment of FIG. 3, since the transistor 324 is disposed between the voltage input terminal 121 and the power switch 122, the voltage Vd on the voltage input terminal 121 is not directly transmitted to the power switch 122, so the power switch 122 can be lowered. The requirement for high voltage resistance further reduces the hardware cost of the power switch 122.

Similar to the previous embodiment, after the control signal generator 123 is activated, the control circuit 120 can operate normally without relying on the bias voltage provided by other external bias coils. Therefore, no additional setting is required in the flyback regulator 300. The bias coil can reduce the complexity and overall cost of the flyback regulator 300 in circuit design. In one embodiment, the transistor 124 and the transistor 324 in the control circuit 120 can be implemented with two depleted galvanic half field effect transistors. In another embodiment, the transistor 124 and the transistor 324 can be cut from the same depleted metal oxide half field effect transistor wafer, and the first end of the depleted gold oxide half field effect transistor wafer (eg, the drain) It is shared by transistor 124 and transistor 324 to further reduce circuit cost.

Other descriptions of the embodiments, modes of operation, and related advantages of the first embodiment of FIG. 1 are also applicable to the flyback regulator 300 of FIG. 3, and the description thereof will not be repeated here for the sake of brevity.

The aforementioned control circuit 120 can also be applied in the architecture of a boost regulator or a buck regulator. For example, FIG. 4 is a simplified functional block diagram of a boost regulator 400 in accordance with an embodiment of the present invention. The boost regulator 400 includes a bridge rectifier 110, an inductor 412, a feedback circuit 414, a control circuit 120, and other circuit components. The control circuit 120 is used to control the operation of the boost regulator 400 to cause the boost regulator 400 to convert the input voltage Vin into a stable output voltage Vout for use by the subsequent stage load. Similar to the foregoing embodiment, the voltage input terminal 121 of the control circuit 120 in FIG. 4 is also coupled to one end (eg, a current output terminal) of the inductor 412 in the boost regulator 400, and the control in the control circuit 120. The signal generator 123 also generates a control signal CS based on the feedback signal FB generated by the feedback circuit 414 to control the operation of the power switch 122.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 120 of FIGS. 1 and 3 above are also applicable to the control circuit 120 of FIG. 4, and the description thereof will not be repeated here for the sake of brevity.

FIG. 5 is a simplified functional block diagram of a symmetrical buck regulator 500 according to an embodiment of the invention. The buck regulator 500 includes an inductor 512, a feedback circuit 514, a drive circuit 516, a power switch 518, a control circuit 120, and other circuit components. The control circuit 120 is used to control the operation of the buck regulator 500 to cause the buck regulator 500 to convert the input voltage Vin into a stable output voltage Vout for use by the subsequent stage load. Similar to the previous embodiment, the voltage input terminal 121 of the control circuit 120 of FIG. 5 is also coupled to one end (eg, a current input terminal) of the inductor 512 in the buck regulator 500. In the present embodiment, the power switch 518 is used as the upper bridge power switch of the buck regulator 500, and the power switch 122 in the control circuit 120 is used as the lower bridge of the buck regulator 500. Power switch. The control signal generator 123 in the control circuit 120 also generates a control signal CS based on the feedback signal FB generated by the feedback circuit 514 to control the operation of the power switch 122. The driving circuit 516 of the buck regulator 500 generates an upper bridge control signal UG according to the control signal CS to control the operation of the power switch 518.

In practice, the driver circuit 516 in the buck regulator 500 can also be integrated into the control signal generator 123 of the control circuit 120 to simplify the circuit design of the buck regulator 500.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 120 of FIGS. 1 and 3 above are also applicable to the control circuit 120 of FIG. 5, and the description thereof will not be repeated here for the sake of brevity.

In practice, the power switch 122 in the aforementioned control circuit 120 can also be set in other functional blocks of the voltage regulator.

For example, FIG. 6 is a simplified functional block diagram of a flyback regulator 600 according to another embodiment of the present invention. The flyback regulator 600 includes a bridge rectifier 110, an inductor 112, a feedback circuit 114, a control circuit 620, and other circuit components. The flyback regulator 600 and the control circuit 620 are similar to the flyback regulator 300 and the control circuit 120 of FIG. 3 described above, with the difference that the setting positions of the power switches 122 are different. In the embodiment of FIG. 3, power switch 122 is integrated into control circuit 120, but in the embodiment of FIG. 6, power switch 122 is disposed external to control circuit 620.

As shown in FIG. 6 , the control circuit 620 further includes a switch connection end 621 for coupling the first end of the power switch 122 in the voltage regulator 610 . The second end of the transistor 324 in the control circuit 620 is coupled to the first end of the power switch 122 in the voltage regulator 610 through the switch connection 621. Similar to the embodiment of FIG. 3, the voltage input 121 of the control circuit 620 of FIG. 6 is also used to couple one end (eg, the current output) of the inductor 112 in the flyback regulator 600. The control signal generator 123 in the control circuit 620 is configured to couple the control end of the power switch 122 and generate a control signal CS according to the feedback signal FB generated by the feedback circuit 114 to control the flyback regulator 600. The operation of the power switch 122.

As in the embodiment of FIG. 3, since the transistor 324 is disposed between the voltage input terminal 121 and the power switch 122, the voltage Vd on the voltage input terminal 121 is not directly transmitted to the power switch 122, so the power switch 122 can be lowered. The requirement for high voltage resistance further reduces the hardware cost of the power switch 122.

Similarly, after the control signal generator 123 in the control circuit 620 is activated, the control circuit 620 can operate normally without relying on the bias voltage provided by other external bias coils. Therefore, no additional need is required in the flyback regulator 600. The additional bias coil is provided, which reduces the complexity and overall cost of the flyback regulator 600 in circuit design.

Other descriptions of the embodiments, modes of operation, and related advantages of the embodiments of Figures 1 and 3 above are also applicable to the flyback regulator 600 of Figure 6, which will not be repeated here for the sake of brevity.

The aforementioned control circuit 620 can also be applied in the architecture of a boost regulator or a buck regulator. For example, FIG. 7 is a simplified functional block diagram of a boost regulator 700 according to another embodiment of the present invention. The boost regulator 700 includes a bridge rectifier 110, a power switch 122, an inductor 412, a feedback circuit 414, a control circuit 620, and other circuit components. Control circuit 620 is used to control the operation of boost regulator 700 to cause boost regulator 700 to convert input voltage Vin to a stable output voltage Vout for use by the downstream load. Similar to the embodiment of FIG. 6, the voltage input terminal 121 of the control circuit 620 of FIG. 7 is also used to couple one end of the inductor 412 (eg, current output terminal) in the boost regulator 700, and the switch of the control circuit 620. The connection terminal 621 is also used to couple the first end of the power switch 122 in the boost regulator 700, and the control signal generator 123 in the control circuit 620 is also based on the feedback signal FB generated by the feedback circuit 414. A control signal CS is generated to control the operation of the power switch 122 in the boost regulator 700.

Other descriptions of the implementations, modes of operation, and related advantages of control circuit 120 and control circuit 620 in the foregoing embodiments are also applicable to control circuit 620 of FIG. 7, which will not be repeated herein for the sake of brevity.

FIG. 8 is a simplified functional block diagram of a symmetric buck regulator 800 in accordance with another embodiment of the present invention. The buck regulator 800 includes a power switch 122, an inductor 512, a feedback circuit 514, a drive circuit 816, a power switch 518, a control circuit 620, and other circuit components. Control circuit 620 is used to control the operation of buck regulator 800 to cause buck regulator 800 to convert input voltage Vin to a stable output voltage Vout for use by the post-stage load. Similar to the foregoing embodiment, the voltage input terminal 121 of the control circuit 620 in FIG. 8 is also coupled to one end (eg, a current input terminal) of the inductor 512 in the buck regulator 800, and the switch connection of the control circuit 620. The terminal 621 is also coupled to the first end of the power switch 122 in the buck regulator 800, and the control signal generator 123 in the control circuit 620 also generates control according to the feedback signal FB generated by the feedback circuit 514. Signal CS. In the present embodiment, the power switch 518 is used as the upper bridge power switch of the buck regulator 800, and the power switch 122 is used as the lower bridge power switch of the buck regulator 800. The driving circuit 816 in the buck regulator 800 generates an upper bridge control signal UG and a lower bridge control signal LG according to the control signal CS generated by the control circuit 620 to control the operation of the power switch 518 and the power switch 122, respectively.

In practice, the driver circuit 816 in the buck regulator 800 can also be integrated into the control signal generator 123 of the control circuit 620 to simplify the circuit design of the buck regulator 800.

Other descriptions of the implementations, modes of operation, and related advantages of control circuit 120 and control circuit 620 in the foregoing embodiments are also applicable to control circuit 620 of FIG. 8, which will not be repeated herein for the sake of brevity.

FIG. 9 is a simplified functional block diagram of a flyback regulator 900 according to another embodiment of the present invention. The flyback regulator 900 includes a bridge rectifier 110, a power switch 122, an inductor 112, a feedback circuit 114, a control circuit 920, and other circuit components. The flyback regulator 900 and the control circuit 920 are similar to the flyback regulator 100 and the control circuit 120 of FIG. 1 described above, with the difference that the setting positions of the power switches 122 are different. In the embodiment of FIG. 1, power switch 122 is integrated into control circuit 120, but in the embodiment of FIG. 9, power switch 122 is disposed external to control circuit 920.

As shown in FIG. 9, the first end of the power switch 122 is coupled to one end of the inductor 112 (eg, the current output terminal), and the second end of the power switch 122 is coupled to a fixed potential (eg, a ground terminal). Similar to the previous embodiment, the voltage input 121 of the control circuit 920 of FIG. 9 is also used to couple one end (current output) of the inductor 112 in the flyback regulator 900. The control signal generator 123 in the control circuit 920 is configured to couple the control end of the power switch 122 and generate a control signal CS according to the feedback signal FB generated by the feedback circuit 114 to control the flyback regulator 900. The operation of the power switch 122.

Compared with the foregoing embodiment of FIG. 1, since the power switch 122 of the flyback regulator 900 is disposed outside the control circuit 920, the circuit area of the control circuit 920 can be further reduced.

Similarly, after the control signal generator 123 in the control circuit 920 is activated, the control circuit 920 can operate normally without relying on the bias voltage provided by other external bias coils. Therefore, no additional is required in the flyback regulator 900. The additional bias coils are provided, which reduces the complexity and overall cost of the flyback regulator 900 in circuit design.

Other descriptions of the embodiments, modes of operation, and related advantages of the first embodiment of FIG. 1 are also applicable to the flyback regulator 900 of FIG. 9, which will not be repeated here for the sake of brevity.

The aforementioned control circuit 920 can also be applied in the architecture of a boost regulator or a buck regulator. For example, FIG. 10 is a simplified functional block diagram of a boost regulator 1000 according to another embodiment of the present invention. The boost regulator 1000 includes a bridge rectifier 110, a power switch 122, an inductor 412, a feedback circuit 414, a control circuit 920, and other circuit components. Control circuit 920 is used to control the operation of boost regulator 1000 to cause boost regulator 1000 to convert input voltage Vin to a stable output voltage Vout for use by a subsequent stage load. Similar to the embodiment of FIG. 9, the voltage input terminal 121 of the control circuit 920 in FIG. 10 is also coupled to one end (eg, a current output terminal) of the inductor 412 in the boost regulator 1000, and in the control circuit 920. The control signal generator 123 also generates a control signal CS based on the feedback signal FB generated by the feedback circuit 414 to control the operation of the power switch 122 in the boost regulator 1000.

Other descriptions of the implementations, modes of operation, and related advantages of the control circuit 120 and the control circuit 920 in the foregoing embodiments are also applicable to the control circuit 920 of FIG. 10, and the description thereof will not be repeated here for the sake of brevity.

FIG. 11 is a simplified functional block diagram of a symmetric buck regulator 1100 according to another embodiment of the present invention. The buck regulator 1100 includes a power switch 122, an inductor 512, a feedback circuit 514, a drive circuit 816, a power switch 518, a control circuit 920, and other circuit components. Control circuit 920 is used to control the operation of buck regulator 1100 to cause buck regulator 1100 to convert input voltage Vin to a stable output voltage Vout for use by the post-stage load. Similar to the foregoing embodiment, the voltage input terminal 121 of the control circuit 920 in FIG. 11 is also coupled to one end (eg, a current input terminal) of the inductor 512 in the buck regulator 1100, and the control in the control circuit 920. The signal generator 123 also generates the control signal CS based on the feedback signal FB generated by the feedback circuit 514. In the present embodiment, the power switch 518 is used as the upper bridge power switch of the buck regulator 1100, and the power switch 122 is used as the lower bridge power switch of the buck regulator 1100. The driving circuit 816 in the buck regulator 1100 generates an upper bridge control signal UG and a lower bridge control signal LG according to the control signal CS generated by the control circuit 920 to control the operation of the power switch 518 and the power switch 122, respectively.

In practice, the driver circuit 816 in the buck regulator 1100 can also be integrated into the control signal generator 123 of the control circuit 920 to simplify the circuit design of the buck regulator 1100.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 120 and the control circuit 920 in the foregoing embodiments are also applicable to the control circuit 920 of FIG. 11, and the description thereof will not be repeated here for the sake of brevity.

As previously mentioned, the buck regulators 500, 800, and 1100 of Figures 5, 8, and 11 are symmetrical buck regulator architectures. In practice, the control circuit 120, 620, or 920 proposed by the present invention can also be applied to the architecture of an asymmetric buck regulator. For example, FIG. 12 is a simplified functional block diagram of an asymmetric buck regulator 1200 in accordance with an embodiment of the present invention. In the present embodiment, the buck regulator 1200 includes an inductor 1212, a feedback circuit 1214, a diode 1216, a control circuit 120, and other circuit components. The control circuit 120 is used to control the operation of the buck regulator 1200 to cause the buck regulator 1200 to convert the input voltage Vin into a stable output voltage Vout for use by the post-stage load. The voltage input terminal 121 of the control circuit 120 in FIG. 12 is coupled to the input voltage Vin of the buck regulator 1200. The second end of the power switch 122 is coupled to the inductor 1212 and the diode 1216. The control signal generator 123 in the control circuit 120 generates a control signal CS based on the feedback signal FB generated by the feedback circuit 1214 to control the operation of the power switch 122.

In practice, the diode 1216 in the buck regulator 1200 can also be integrated into the control circuit 120 to simplify the circuit design of the buck regulator 1200.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 120 in the foregoing embodiments are also applicable to the control circuit 120 of FIG. 12, and the description thereof will not be repeated here for the sake of brevity.

FIG. 13 is a simplified functional block diagram of an asymmetric buck regulator 1300 according to another embodiment of the present invention. In the present embodiment, the buck regulator 1300 includes a power switch 122, an inductor 1212, a feedback circuit 1214, a diode 1216, a control circuit 620, and other circuit components. The control circuit 620 is used to control the operation of the buck regulator 1300 to cause the buck regulator 1300 to convert the input voltage Vin into a stable output voltage Vout for use by the post-stage load. The voltage input terminal 121 of the control circuit 620 in FIG. 13 is coupled to the input voltage Vin of the buck regulator 1300. The switch connection end 621 of the control circuit 620 is coupled to the first end of the power switch 122. The second end of the power switch 122 is coupled to the inductor 1212 and the diode 1216. The control signal generator 123 in the control circuit 620 also generates a control signal CS based on the feedback signal FB generated by the feedback circuit 1214 to control the operation of the power switch 122.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 620 of the previous embodiments are also applicable to the control circuit 620 of FIG. 13, which will not be repeated herein for the sake of brevity.

FIG. 14 is a simplified functional block diagram of an asymmetric buck regulator 1400 according to another embodiment of the present invention. In the present embodiment, the buck regulator 1400 includes a power switch 122, an inductor 1212, a feedback circuit 1214, a diode 1216, a control circuit 920, and other circuit components. Control circuit 920 is used to control the operation of buck regulator 1400 to cause buck regulator 1400 to convert input voltage Vin to a stable output voltage Vout for use by the post-stage load. The voltage input terminal 121 of the control circuit 920 in FIG. 14 is coupled to the input voltage Vin of the buck regulator 1400 and the first end of the power switch 122. The second end of the power switch 122 is coupled to the inductor 1212 and the diode 1216. The control signal generator 123 in the control circuit 920 also generates a control signal CS based on the feedback signal FB generated by the feedback circuit 1214 to control the operation of the power switch 122.

Other descriptions of the embodiments, modes of operation, and related advantages of the control circuit 920 in the previous embodiments are also applicable to the control circuit 920 of FIG. 14, which will not be repeated here for the sake of brevity.

In some of the foregoing embodiments, the control terminal of the transistor 324 in the control circuit 120 or the control circuit 620 is coupled to the output of the control signal generator 123, but this is only an embodiment, and is not limited to the foregoing control circuit. 120 or a practical implementation of control circuit 620. For example, in some embodiments in which the transistor 324 is implemented as a depleted galvanic half field effect transistor, the control terminal of the transistor 324 can be recoupled to a fixed potential (eg, ground) to enable the transistor. 324 remains in a turn on state.

In addition, the bridge rectifier 110 in the foregoing partial embodiments may be implemented by using another rectifier architecture. In some embodiments, the bridge rectifier 110 can even be omitted. For example, when the regulator can receive the DC input voltage Vin from other pre-stage circuits, the bridge rectifier 110 can be omitted.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the claims of the present invention are intended to be within the scope of the present invention.

100, 300, 600, 900. . . Flyback regulator

110. . . Bridge rectifier

112, 412, 512, 1212. . . inductance

114, 414, 514, 127, 1214. . . Feedback circuit

116. . . Bias coil

120, 620, 920. . . Control circuit

121. . . Voltage input

122. . . Power switch

123. . . Control signal generator

124, 324. . . Transistor

125. . . Reference voltage controller

126. . . Comparators

128, 1216. . . Dipole

129. . . Current limiter

130. . . capacitance

400, 700, 1000. . . Boost regulator

500, 800, 1100, 1200, 1300, 1400. . . Buck regulator

621. . . Switch connector

1 is a simplified functional block diagram of an embodiment of a flyback regulator of the present invention.

2 is a simplified timing diagram of an operational embodiment of the control circuit of FIG. 1.

3 is a simplified functional block diagram of another embodiment of a flyback regulator of the present invention.

4 is a simplified functional block diagram of an embodiment of a boost regulator of the present invention.

FIG. 5 is a simplified functional block diagram of an embodiment of a buck regulator of the present invention.

6 is a simplified functional block diagram of another embodiment of a flyback regulator of the present invention.

Figure 7 is a simplified functional block diagram of another embodiment of the boost regulator of the present invention.

Figure 8 is a simplified functional block diagram of another embodiment of a buck regulator of the present invention.

9 is a simplified functional block diagram of another embodiment of a flyback regulator of the present invention.

Figure 10 is a simplified functional block diagram of another embodiment of the boost regulator of the present invention.

11 to 14 are simplified functional block diagrams of different embodiments of the buck regulator of the present invention.

100. . . Flyback regulator

110. . . Bridge rectifier

112. . . inductance

114, 127. . . Feedback circuit

116. . . Bias coil

120. . . Control circuit

12. . . Voltage input

122. . . Power switch

123. . . Control signal generator

124. . . Transistor

125. . . Reference voltage controller

126. . . Comparators

128. . . Dipole

129. . . Current limiter

130. . . capacitance

Claims (41)

A control circuit for a voltage regulator, the voltage regulator comprising an inductor, the control circuit comprising:
a power switch
a voltage input end for coupling one end of the inductor;
a control signal generator coupled to the control end of the power switch for controlling the operation of the power switch;
a first transistor is coupled to the voltage input terminal and the first end of the power switch, and the second end of the first transistor is coupled to the control signal generator;
a reference voltage controller for controlling a reference voltage;
a comparator coupled to the reference voltage controller, the control end of the first transistor, and a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to And controlling a magnitude of an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator for generating the feedback signal according to the operating voltage. The control circuit of claim 1, wherein the reference voltage controller sets the reference voltage to a first level before a first time point such that the operating voltage gradually increases with voltage on the voltage input terminal. Raising to a first predetermined voltage value, and the reference voltage controller reduces the reference voltage to a second level after the first time point to gradually decrease the operating voltage to a second predetermined voltage value;
When the operating voltage drops to the second predetermined voltage value, the comparator controls the operation of the first transistor to maintain the operating voltage at the second predetermined voltage value. The control circuit of claim 2, wherein the current limiter is disposed on a signal path between the second end of the first transistor and the feedback circuit. The control circuit of claim 3, wherein the current limiter is a resistor, a junction field calibrator, or a depleted MOSFET. The control circuit of claim 1, further comprising:
A diode is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 1, further comprising:
A current limiter is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 6, wherein the current limiter is a resistor, a junction field calibrator, or a depleted MOSFET. The control circuit of claim 7, wherein the current limiter is coupled between the second end of the first transistor and the feedback circuit. The control circuit according to any one of claims 1 to 8, further comprising:
a second transistor, wherein the first end of the second transistor is coupled to the voltage input end, the second end is coupled to the first end of the power switch, and the control end is coupled to the control signal generator or A fixed potential. The control circuit of claim 9, wherein the first transistor and the second transistor are cut by using the same depleted metal oxide half field effect transistor wafer, and the depleted gold oxide half field effect transistor wafer The drain is shared by the first transistor and the second transistor. A control circuit for a voltage regulator, the voltage regulator comprising a power switch and an inductor, the control circuit comprising:
a voltage input end for coupling one end of the inductor;
a control signal generator for coupling a control end of the power switch to control operation of the power switch;
a first transistor, the first end of which is coupled to the voltage input end, and the second end of the first transistor is coupled to the control signal generator;
a reference voltage controller for controlling a reference voltage;
a comparator coupled to the reference voltage controller, the control terminal of the first transistor, and a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to And controlling a magnitude of an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator for generating the feedback signal according to the operating voltage. The control circuit of claim 11, wherein the reference voltage controller sets the reference voltage to a first level before a first time point such that the operating voltage gradually increases with voltage on the voltage input terminal. Raising to a first predetermined voltage value, and the reference voltage controller reduces the reference voltage to a second level after the first time point to gradually decrease the operating voltage to a second predetermined voltage value;
When the operating voltage drops to the second predetermined voltage value, the comparator controls the operation of the first transistor to maintain the operating voltage at the second predetermined voltage value. The control circuit of claim 12, wherein the current limiter is disposed on a signal path between the second end of the first transistor and the feedback circuit. The control circuit of claim 13, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 11 further comprising:
A diode is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 11 further comprising:
A current limiter is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 16, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 17, wherein the current limiter is coupled between the second end of the first transistor and the feedback circuit. The control circuit according to any one of claims 11 to 18, further comprising:
a second transistor, wherein the first end of the second transistor is coupled to the voltage input end, the second end is coupled to the first end of the power switch, and the control end is coupled to the control signal generator Or a fixed potential. The control circuit as claimed in claim 19, wherein the first transistor and the second transistor are cut by using the same depleted metal oxide half field effect transistor wafer, and the depleted gold oxide half field effect transistor wafer The drain is shared by the first transistor and the second transistor. A method of controlling a voltage regulator comprising an inductor and a power switch, the method comprising:
Providing a voltage input end for coupling one end of the inductor;
Providing a control signal generator for coupling the control end of the power switch to control the operation of the power switch;
Providing a first transistor, the first end of which is coupled to the voltage input end, and the second end of the first transistor is coupled to the control signal generator;
Generating a reference voltage;
Comparing the reference voltage and a feedback signal to switch the operation of the first transistor to control a magnitude of an operating voltage of the control signal generator; and generating the feedback signal according to the operating voltage. A control circuit for a voltage regulator, the voltage regulator comprising an inductor and a diode, the control circuit comprising:
a power switch having a second end for coupling to the inductor and the diode;
a voltage input terminal for coupling an input voltage of the voltage regulator;
a control signal generator coupled to the control end of the power switch for controlling the operation of the power switch;
a first transistor is coupled to the voltage input terminal and the first end of the power switch, and the second end of the first transistor is coupled to the control signal generator;
a reference voltage controller for controlling a reference voltage;
a comparator coupled to the reference voltage controller, the control end of the first transistor, and a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to And controlling a magnitude of an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator for generating the feedback signal according to the operating voltage. The control circuit of claim 22, wherein the reference voltage controller sets the reference voltage to a first level before a first time point such that the operating voltage gradually increases with voltage on the voltage input terminal Raising to a first predetermined voltage value, and the reference voltage controller reduces the reference voltage to a second level after the first time point to gradually decrease the operating voltage to a second predetermined voltage value;
When the operating voltage drops to the second predetermined voltage value, the comparator controls the operation of the first transistor to maintain the operating voltage at the second predetermined voltage value. The control circuit of claim 23, wherein the current limiter is disposed on a signal path between the second end of the first transistor and the feedback circuit. The control circuit of claim 24, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 22, further comprising:
A diode is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 22, further comprising:
A current limiter is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 27, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 28, wherein the current limiter is coupled between the second end of the first transistor and the feedback circuit. The control circuit according to any one of claims 22 to 29, further comprising:
a second transistor, wherein the first end of the second transistor is coupled to the voltage input end, the second end is coupled to the first end of the power switch, and the control end is coupled to the control signal generator or A fixed potential. The control circuit of claim 30, wherein the first transistor and the second transistor are cut by the same depleted MOS field-effect transistor wafer, and the depleted MOS field-effect transistor wafer The drain is shared by the first transistor and the second transistor. A control circuit for a voltage regulator, the voltage regulator comprising a power switch and an inductor, the control circuit comprising:
a voltage input terminal for coupling an input voltage of the voltage regulator;
a control signal generator for coupling a control end of the power switch to control operation of the power switch;
a first transistor, the first end of which is coupled to the voltage input end, and the second end of the first transistor is coupled to the control signal generator;
a reference voltage controller for controlling a reference voltage;
a comparator coupled to the reference voltage controller, the control terminal of the first transistor, and a feedback signal for comparing the reference voltage and the feedback signal to switch the operation of the first transistor to And controlling a magnitude of an operating voltage of the control signal generator; and a feedback circuit coupled to the comparator for generating the feedback signal according to the operating voltage. The control circuit of claim 32, wherein the reference voltage controller sets the reference voltage to a first level before a first time point such that the operating voltage gradually increases with voltage on the voltage input terminal. Raising to a first predetermined voltage value, and the reference voltage controller reduces the reference voltage to a second level after the first time point to gradually decrease the operating voltage to a second predetermined voltage value;
When the operating voltage drops to the second predetermined voltage value, the comparator controls the operation of the first transistor to maintain the operating voltage at the second predetermined voltage value. The control circuit of claim 33, wherein the current limiter is disposed on a signal path between the second end of the first transistor and the feedback circuit. The control circuit of claim 34, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 32, further comprising:
A diode is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 32, further comprising:
A current limiter is disposed on the signal path between the voltage input terminal and the feedback circuit. The control circuit of claim 37, wherein the current limiter is a resistor, a junction field galvanic crystal, or a depleted galvanic half field effect transistor. The control circuit of claim 38, wherein the current limiter is coupled between the second end of the first transistor and the feedback circuit. The control circuit according to any one of claims 32 to 39, further comprising:
a second transistor, wherein the first end of the second transistor is coupled to the voltage input end, the second end is coupled to the first end of the power switch, and the control end is coupled to the control signal generator Or a fixed potential. The control circuit of claim 40, wherein the first transistor and the second transistor are cut by using the same depleted metal oxide half field effect transistor wafer, and the depleted metal oxide half field effect transistor wafer The drain is shared by the first transistor and the second transistor.