TWI786875B - Control Module of Power Correction Circuit - Google Patents

Abstract

A control module of a power correction circuit, comprising a control unit, a main voltage feedback unit and a secondary voltage feedback unit, the control unit is connected to at least one power switch, and the main voltage feedback unit is connected to a power correction circuit The output terminal and the control unit, the secondary voltage feedback unit is connected to the output terminal and the control unit, the secondary voltage feedback unit includes a voltage dividing circuit connected to the output terminal and having at least one voltage dividing node and a voltage dividing circuit connected to the The voltage dividing node and the voltage limiting circuit of the control unit, the voltage limiting circuit has a first state of being inactive when the voltage of the voltage dividing node is not higher than a reference voltage, and a first state when the voltage of the voltage dividing node is higher than a reference voltage The reference voltage interferes with a second state of a feedback voltage provided by the main voltage feedback unit to the control unit with an interference voltage.

Description

Control module of power correction circuit

The invention relates to a control module of a power correction circuit, in particular to a control module of a power correction circuit capable of clamping a feedback voltage.

The control module of the power correction circuit generally has a feedback control mechanism, based on the voltage at the output end of the power correction circuit to correct whether the current control is appropriate.

In practice, the voltage at the output end of the power correction circuit will vary with the load of the downstream stage. In plain words, the higher the demand of the rear end, the higher the power provided by the power correction circuit. However, the post-stage load of the power correction circuit does not always remain constant. If the load suddenly drops, the power correction circuit needs to have a significant increase in the output voltage to make the control module respond to the control required by the load reduction through feedback. , but in fact there has been a problem of response delay, so that the power correction circuit will still output a higher voltage for a period of time. Higher voltage, too high voltage will put the high voltage capacitor in a dangerous environment.

In this regard, in order to solve this problem, some operators choose capacitors with higher withstand voltage specifications for implementation, but the problem that follows is rising costs.

The main purpose of the present invention is to solve the problem that the feedback response of the conventional power correction circuit is too slow, which leads to the problem that the downstream matching circuit cannot be effectively protected.

To achieve the above object, the present invention provides a control module of a power correction circuit, comprising a control unit, a main voltage feedback unit and a secondary voltage feedback unit, the control unit is connected to at least one power switch of the power correction circuit, The main voltage feedback unit is connected to an output terminal of the power correction circuit and the control unit, the secondary voltage feedback unit is connected to the output terminal of the power correction circuit and the control unit, and the secondary voltage feedback unit includes an output terminal connected to the The output terminal also has a voltage dividing circuit of at least one voltage dividing node and a voltage limiting circuit connecting the voltage dividing node and the control unit, and the voltage limiting circuit has a function when the voltage of the voltage dividing node is not higher than a reference voltage A first state of not interfering with a feedback voltage provided by the main voltage feedback unit to the control unit, and interfering with the main voltage feedback unit to the control unit with an interference voltage when the node voltage is higher than the reference voltage The second state of the feedback voltage is provided.

In one embodiment, the voltage limiting circuit includes a comparator and a diode connected to the comparator, the comparator has a non-inverting input terminal connected to the voltage dividing node, an inverting input terminal receiving the reference voltage, And a comparator output terminal connected to the diode, the diode has a positive pole connected to an output terminal of the comparator, and a negative pole connected to the control unit.

In one embodiment, the voltage limiting circuit includes a first resistor and a first capacitor connected in series with the first resistor, the first resistor and the first capacitor form a first resistor connected to the output terminal of the comparator A series node, the end of the first resistor not connected in series with the first capacitor is connected to an operating voltage source.

In one embodiment, the voltage limiting circuit includes a second resistor connected to the negative pole of the diode.

In one embodiment, the voltage limiting circuit includes a reference voltage generating circuit for generating the reference voltage, the reference voltage generating circuit includes a third resistor connected to a working voltage source, and a third resistor connected in series with the third resistor to form a The three-terminal adjustable shunt reference source of the second series node, a voltage-dividing bypass connected in parallel with the three-terminal adjustable shunt reference source, and a second voltage-dividing bypass connected in parallel with the three-terminal adjustable shunt reference source and the voltage-dividing bypass Two capacitors, the voltage-dividing bypass includes at least two voltage-dividing resistors and at least one bypass node formed by the voltage-dividing resistors, the three-terminal adjustable shunt reference source has a reference terminal connected to the bypass node, and the reference The voltage is the voltage value of the second series node.

In one embodiment, the reference voltage is generated by the comparator.

In one embodiment, the power correction circuit is a bridged power correction circuit.

In one embodiment, the power correction circuit is a bridgeless power correction circuit.

Through the foregoing implementation of the present invention, compared with conventional ones, it has the following characteristics: the present invention uses the secondary voltage feedback unit different from the main voltage feedback unit to increase the voltage at the output terminal of the power correction circuit and meet the second When the trigger condition of the state, interfere with the feedback voltage received by the control unit, so that the control unit can make sufficient control in advance, so as to avoid the back-stage matching circuit (such as high-voltage capacitor) from being subjected to excessive voltage, so that the back-stage matching circuit can be are effectively protected.

The detailed description and technical content of the present invention are described as follows in conjunction with the drawings:

Please refer to FIG. 1 to FIG. 3, the present invention provides a control module 10, the control module 10 is mainly used to control the work of a power correction circuit 20, before describing the control module 10, it should be understood that the present invention is not limited The configuration of the power correction circuit 20 can be applied to any power correction circuit 20 that can perform feedback control today. Figures 1 and 2 of this paper show the implementation status of the power correction circuit 20 when it is a bridge type. Figures 5 to 5 6 is the implementation state when the power correction circuit 20 is bridgeless. Please refer to FIGS. 1 to 3. The control module 10 of the present invention includes a control unit 11, a main voltage feedback unit 12, and a secondary voltage feedback unit 13. The control unit 11 is connected to the power correction circuit 20. At least one power switch 201, the control unit 11 is based on a feedback voltage 121 provided by the main voltage feedback unit 12 and the auxiliary voltage feedback unit 13 and a feedback current signal 161 obtained from the power correction circuit 20, It is determined to provide an on-off signal 111 of the power switch 201 , and the on-off signal 111 determines the operation of the power switch 201 . Furthermore, the control unit 11 may be implemented by a chip and a plurality of electronic components matched with the chip.

On the other hand, the main voltage feedback unit 12 is connected to an output terminal 202 of the power correction circuit 20 and the control unit 11, and the main voltage feedback unit 12 can adopt a method commonly used in the feedback control of the power correction circuit 20 today. Any kind of feedback circuit implementation, the main voltage feedback unit 12 is an important part of the control unit 11 to implement the feedback control, the main voltage feedback unit 12 has no state difference, and the power correction circuit 20 will report to the control unit after it is started. 11 provides the feedback voltage 121 .

Furthermore, the auxiliary voltage feedback unit 13 is connected to a feedback input terminal 112 of the control unit 11 as the main voltage feedback unit 12, and the auxiliary voltage feedback unit 13 includes a voltage dividing circuit 131 and a voltage limiting The circuit 132 , the voltage dividing circuit 131 is connected to the output terminal 202 and has at least one voltage dividing node 133 , wherein the voltage dividing circuit 131 includes at least two resistors 134 connected in series. Moreover, the voltage limiting circuit 132 is connected to the voltage dividing node 133 and the control unit 11, and the voltage limiting circuit 132 has a circuit which does not interfere with the main voltage when the voltage of the voltage dividing node 133 is not higher than a reference voltage (Vref). The first state of the feedback voltage 121 provided by the granting unit 12 to the control unit 11, and an interference voltage 135 interferes with the main voltage feedback when the voltage of the voltage dividing node 133 is higher than the reference voltage (Vref). The second state of the feedback voltage 121 provided by the unit 12 to the control unit 11 .

As can be seen from the foregoing, the auxiliary voltage feedback unit 13 of the present invention only acts on the control unit 11 when certain conditions are met, and the auxiliary voltage feedback unit 13 will not interfere with the main voltage feedback unit 12 for the rest of the time. The feedback voltage 121 provided by the input terminal 112 . Furthermore, since the voltage at the output terminal 202 of the power factor correction circuit 20 is not constant, it will vary with the load of the power factor correction circuit 20 , which means that the voltage of the voltage dividing node 133 will also vary accordingly. Referring again to FIG. 1, when the voltage of the voltage dividing node 133 is lower than the reference voltage (Vref), the secondary voltage feedback unit 13 is in the first state, and the voltage limiting circuit 132 does not respond to the control unit 11. The feedback input terminal 112 provides any voltage for feedback control. Referring again to FIG. 3, when the voltage of the voltage dividing node 133 is higher than the reference voltage (Vref), the secondary voltage feedback unit 13 enters the second state, and the voltage limiting circuit 132 outputs the interference to the control unit 11. The voltage 135 (which can be regarded as another feedback voltage) interferes with the feedback voltage 121 provided by the main voltage feedback unit 12 to the control unit 11, so that the control unit 11 performs the start-up based on the voltage value after the interference voltage 135 interferes. Modulation of closed signal 111. In this way, the problem that the feedback response of the power correction circuit 20 is too slow, resulting in the need to increase the withstand voltage design of the downstream matching circuit (such as the high-voltage capacitor 30 ). In other words, the arrangement of the auxiliary voltage feedback unit 13 enables the downstream matching circuit of the power correction circuit 20 to be effectively protected without having to withstand excessive withstand voltage.

Since the voltage at the output terminal 202 of the power factor correction circuit 20 is relatively high, it is difficult to be directly used for feedback control. Generally, the voltage at the output terminal 202 is divided by the aforementioned voltage divider circuit 131 to obtain A voltage that is more in line with the working requirements. However, when the present invention is implemented, the voltage dividing circuit 131 included in the secondary voltage feedback unit 13 is not shared with the main voltage feedback unit 12, and the main voltage feedback unit 12 will use another voltage dividing circuit ( not shown in the figure) implementation.

Referring again to FIG. 3 , in one embodiment, the voltage limiting circuit 132 includes a comparator 136 and a diode 137 connected to the comparator 136 . The comparator 136 has a non-inverting input 138 connected to the voltage dividing node 133 , an inverting input 139 receiving the reference voltage (Vref), and an output 140 connected to the diode 137 . On the other hand, the diode 137 is used to isolate the main voltage feedback unit 12 and the auxiliary voltage feedback unit 13, the diode 137 has a positive pole 141 connected to the output terminal 140, and a positive pole 141 connected to the control unit 11 negative electrode 142 . In one embodiment, the comparator 136 has a positive power supply terminal 144 connected to a working voltage source 143 , and a negative power supply terminal 145 connected to a ground reference point 146 . In addition, in one embodiment, the voltage limiting circuit 132 further includes a first resistor 147, and a first capacitor 148 connected in series with the first resistor 147, the first resistor 147 and the first capacitor 148 form a A first series node 149 connected to the output terminal 140 of the comparator 136 , the end of the first resistor 147 not in series with the first capacitor 148 is connected to the operating voltage source 143 . Furthermore, the voltage limiting circuit 132 may further include a second resistor 150 connected to the negative electrode 142 of the diode 137 .

Please also refer to FIG. 4 , the aforementioned reference voltage (Vref) can be directly generated by the comparator 136 , or as shown in FIG. 3 . In the embodiment disclosed in FIG. 3 , the voltage limiting circuit 132 includes a reference voltage generating circuit 151 for generating the reference voltage (Vref), and the reference voltage generating circuit 151 includes a third resistor 152 connected to the operating voltage source 143 , a three-terminal adjustable shunt reference source 154 connected in series with the third resistor 152 and forming a second series node 153, a voltage dividing bypass 155 connected in parallel with the three-terminal adjustable shunt reference source 154, and a The three-terminal adjustable shunt reference source 154 and the second capacitor 156 connected in parallel to the voltage-dividing bypass 155, the voltage-dividing bypass 155 includes at least two voltage-dividing resistors 157 and at least one bypass node formed by the voltage-dividing resistors 157 158. In addition, the three-terminal adjustable shunt reference source 154 has a reference terminal 159 connected to the bypass node 158 . In one embodiment, the three-terminal adjustable shunt reference source 154 can be a TL431 electronic component sold in the market today. As above, the reference voltage (Vref) is the voltage value of the second series node 153 .

In summary, the above is only a preferred embodiment of the present invention, and should not limit the implementation scope of the present invention, that is, all equivalent changes and modifications made according to the scope of the patent application of the present invention should still fall within the scope of the patent of the present invention.

10: Control module 11: Control unit 111: opening and closing signal 112: Feedback input terminal 12: Main voltage feedback unit 121: feedback voltage 13: Secondary voltage feedback unit 131: Voltage divider circuit 132: Voltage limiting circuit 133: Voltage divider node 134: resistance 135: Interference voltage 136: Comparator 137: Diode 138: Non-inverting input terminal 139: Inverting input terminal 140: output terminal 141: positive pole 142: negative pole 143: Working voltage source 144: Positive power supply terminal 145: Negative power supply terminal 146: Ground reference point 147: The first resistance 148: The first capacitor 149: The first series node 150: second resistance 151: Reference voltage generating circuit 152: the third resistor 153: Second series node 154: Three-terminal adjustable shunt reference source 155: Voltage divider bypass 156: second capacitor 157: Divider resistor 158:Bypass node 159: Reference end 161: Feedback current signal 20: Power correction circuit 201: Power switch 202: output terminal 30: High voltage capacitor

FIG. 1 is a schematic diagram (1) of the implementation of the control module of the power correction circuit of the present invention. FIG. 2 is an implementation schematic diagram (2) of the control module of the power correction circuit of the present invention. FIG. 3 is a schematic circuit diagram of the first embodiment of the secondary voltage feedback unit of the present invention. FIG. 4 is a schematic circuit diagram of the second embodiment of the secondary voltage feedback unit of the present invention. FIG. 5 is an implementation schematic diagram (3) of the control module of the power correction circuit of the present invention. FIG. 6 is a schematic diagram (4) of the implementation of the control module of the power correction circuit of the present invention.

10: Control module

11: Control unit

111: opening and closing signal

112: Feedback input terminal

12: Main voltage feedback unit

121: feedback voltage

13: Secondary voltage feedback unit

135: Interference voltage

161: Feedback current signal

20: Power correction circuit

201: Power switch

202: output terminal

30: High voltage capacitor

Claims (5)

A control module of a power correction circuit, comprising: a control unit connected to at least one power switch of the power correction circuit; a main voltage feedback unit connected to an output terminal of the power correction circuit and the control unit; and a secondary A voltage feedback unit, connected to the output end of the power correction circuit and the control unit, the secondary voltage feedback unit includes a voltage divider circuit connected to the output end and having at least one voltage divider node and a voltage divider node connected to the voltage divider and the voltage limiting circuit of the control unit, the voltage limiting circuit has a first device that does not interfere with a feedback voltage provided by the main voltage feedback unit to the control unit when the voltage of the voltage dividing node is not higher than a reference voltage state, and a second state in which an interference voltage interferes with the feedback voltage provided by the main voltage feedback unit to the control unit when the voltage of the voltage dividing node is higher than the reference voltage, the voltage limiting circuit includes a comparison A device, a diode connected to the comparator and a reference voltage generating circuit for generating the reference voltage, the comparator has a non-inverting input connected to the voltage dividing node, and an inverting input receiving the reference voltage , and a comparator output terminal connected to the diode, the diode has a positive pole connected to an output terminal of the comparator, and a negative pole connected to the control unit, the reference voltage generation circuit includes a connection to an operating voltage A third resistance of the source, a three-terminal adjustable shunt reference source connected in series with the third resistance and forming a second series node, a voltage divider bypass connected in parallel with the three-terminal adjustable shunt reference source, and a The three-terminal adjustable shunt reference source and the second capacitor connected in parallel with the voltage-dividing bypass include at least two voltage-dividing resistors and at least one bypass node formed by the voltage-dividing resistors. The three-terminal adjustable The shunt reference source has a reference terminal connected to the bypass node, and the reference voltage is the voltage value of the second series node. The control module of the power correction circuit according to claim 1, wherein the voltage limiting circuit includes a first resistor and a first capacitor connected in series with the first resistor, The first resistor and the first capacitor form a first series node connected to the output end of the comparator, and the end of the first resistor not connected in series with the first capacitor is connected to an operating voltage source. The control module of the power correction circuit according to claim 1 or 2, wherein the voltage limiting circuit includes a second resistor connected to the negative pole of the diode. The control module of the power correction circuit as described in claim 1 or 2, wherein the power correction circuit is a bridge-type power correction circuit. The control module of the power correction circuit according to claim 1 or 2, wherein the power correction circuit is a bridgeless power correction circuit.

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