CN112234826B - Primary controller applied to primary side of power converter and method of operation thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种应用于电源转换器的一次侧的初级控制器及其操作方法。所述初级控制器包含一电流补偿电路和一补偿电压产生电路。所述电流补偿电路是用以根据一直流电压和一辅助电压，产生一补偿电流至所述一次侧的传感电阻，其中所述辅助电压和所述电源转换器的二次侧的输出电压有关，且所述补偿电流会改变所述一次侧的峰值电压。所述补偿电压产生电路是用以根据一参考电流、所述二次侧的放电时间和一峰值电流，产生一补偿电压，其中所述参考电流会随所述输出电压改变。所述补偿电流和所述参考电流是用以使所述电源转换器的二次侧的输出电流不随所述输出电压改变。因此，相较于现有技术，本发明可有效消除所述输出电压对所述输出电流的影响。

The invention discloses a primary controller applied to the primary side of a power converter and an operation method thereof. The primary controller includes a current compensation circuit and a compensation voltage generating circuit. The current compensation circuit is used for generating a compensation current to the sensing resistor of the primary side according to a DC voltage and an auxiliary voltage, wherein the auxiliary voltage is related to the output voltage of the secondary side of the power converter , and the compensation current will change the peak voltage of the primary side. The compensation voltage generating circuit is used for generating a compensation voltage according to a reference current, a discharge time of the secondary side and a peak current, wherein the reference current varies with the output voltage. The compensation current and the reference current are used to make the output current of the secondary side of the power converter not change with the output voltage. Therefore, compared with the prior art, the present invention can effectively eliminate the influence of the output voltage on the output current.

Description

Primary controller applied to primary side of power converter and operation method thereof

Technical Field

The present invention relates to a primary controller applied to a primary side of a power converter and an operating method thereof, and more particularly, to a primary controller and an operating method thereof, which can prevent an output current of a secondary side of a power converter from varying with an output voltage of the secondary side of the power converter.

Background

In the prior art, a designer of a constant current (constant current) power converter may control the power converter to be turned on and off by using a primary controller applied to a primary side of the power converter. The primary controller determines a compensation voltage on a compensation pin of the power converter by using a peak current related to a peak voltage of a primary side of the power converter, a discharge time of a secondary side of the power converter and a reference current, and then controls a power switch of the power converter to be turned on and off according to the compensation voltage, wherein the compensation voltage is related to an output voltage of the secondary side of the power converter, and the primary controller makes an output current of the secondary side of the power converter be a constant current by using the negative feedback mechanism. In addition, it should be understood by those skilled in the art that the output current of the secondary side of the power converter is related to the turn ratio of the primary side inductance and the secondary side inductance of the power converter, the peak current, the sensing resistance of the primary side of the power converter, the discharge time of the secondary side, and the switching period of the power switch. Ideally, the output current of the secondary side of the power converter does not change with the output voltage of the secondary side of the power converter, but because the peak current, the discharge time of the secondary side, and the switching period of the power switch change with the output voltage of the secondary side of the power converter, the output current also changes with the output voltage of the secondary side of the power converter. Therefore, how to make the output current not vary with the output voltage on the secondary side of the power converter becomes an important issue for designers of the power converter.

Disclosure of Invention

An embodiment of the invention discloses a primary controller applied to a primary side of a power converter. The primary controller comprises a current compensation circuit and a compensation voltage generation circuit. The current compensation circuit is used for generating a compensation current to the sensing resistor of the primary side according to a direct current voltage and an auxiliary voltage, wherein the auxiliary voltage is related to the output voltage of the secondary side of the power converter, and the compensation current changes the peak voltage of the primary side. The compensation voltage generating circuit is coupled to the current compensation circuit and used for generating a compensation voltage according to a reference current, the discharge time of the secondary side and a peak current, wherein the reference current changes along with the output voltage of the secondary side of the power converter. The compensation current and the reference current are used for keeping the output current of the secondary side of the power converter unchanged along with the output voltage of the secondary side of the power converter.

Another embodiment of the present invention discloses an operating method of a primary controller applied to a primary side of a power converter, wherein the primary controller includes a current compensation circuit, a compensation voltage generation circuit, and a gate control signal generation circuit. The operation method comprises the steps that the current compensation circuit generates a compensation current to a sensing resistor of the primary side according to a direct current voltage and an auxiliary voltage, wherein the auxiliary voltage is related to the output voltage of the secondary side of the power converter, and the compensation current changes the peak voltage of the primary side; the compensation voltage generating circuit generates a compensation voltage according to a reference current, the discharge time of the secondary side and a peak current, wherein the reference current can change along with the output voltage of the secondary side of the power converter; and the grid control signal generating circuit generates a grid control signal to a power switch on the primary side of the power converter according to the compensation voltage, wherein the grid control signal is used for controlling the power switch to be switched on and off. The compensation current and the reference current are used for keeping the output current of the secondary side of the power converter unchanged along with the output voltage of the secondary side of the power converter.

The invention discloses a primary controller applied to a primary side of a power converter and an operation method thereof. The primary controller and the operation method are used for enabling the output current on the secondary side of the power converter not to change along with the output voltage by utilizing the compensation current which is generated by the current compensation circuit of the primary controller and varies in the reverse direction with the output voltage on the secondary side of the power converter and the reference current which is generated by the reference current source of the primary controller and varies in the forward direction with the output voltage. Therefore, compared with the prior art, the compensation current and the reference current are related to the output voltage, so the invention can effectively eliminate the influence of the output voltage on the output current.

Drawings

Fig. 1 is a schematic diagram of a primary controller applied to a primary side of a power converter according to a first embodiment of the present invention.

Fig. 2 is a schematic diagram illustrating a compensation voltage generation circuit within the primary controller for generating the compensation voltage.

Fig. 3 is a diagram illustrating an actual value of the sensing voltage and an ideal value of the sensing voltage.

Fig. 4 is a schematic diagram illustrating a relationship between an output current on the secondary side of the power converter and an input voltage on the primary side of the power converter.

Fig. 5 is a schematic diagram illustrating a current compensation circuit.

Fig. 6 is a schematic diagram illustrating a relationship between the compensation current and the auxiliary voltage.

Fig. 7 is a diagram illustrating the relationship between output current, output voltage and input voltage.

Fig. 8 is a schematic diagram illustrating a reference current source.

Fig. 9 is a diagram illustrating the relationship between the output current, the output voltage, and the input voltage.

Fig. 10 is a flowchart of an operation method of a primary controller applied to a primary side of a power converter according to a second embodiment of the present invention.

Wherein the reference numerals are as follows:

100 power converter

101 voltage dividing circuit

102 power switch

103 auxiliary winding

104 sense resistor

106 primary side winding

108 secondary side winding

110 diode

200 primary controller

202 current compensation circuit

204 compensation voltage generating circuit

2042 reference current source

2044 switch

2046 Peak Current Source

2022 digital-to-analog converter

20242. 20422, 20424 and 20436 operational amplifier

20244. 20426, 20428, 20434, 20438 NMOS metal oxide semiconductor transistors

20246. 20440 resistor

20248. 20250, 20252, 20430 pmos transistors

20442 capacitance

20444 voltage-current converter

CCOMP compensation capacitor

COMP, GATE, ZCD, CS, HV, VCC, pin

GND

DS1, DS2 digital signals

GCS Gate control Signal

I1 first Current

I2 second Current

IPRI, IS current

IOUT output current

Peak current of IPK

IREF reference current

ICC compensation current

PRI Primary side

SEC Secondary side

TDIS discharge time

TON on time

VDC direct voltage

VCOMP compensation voltage

VS sense voltage

Peak voltage of VPK

Ideal peak voltage of VIPK

VAC input voltage

Auxiliary voltage of VZCD

Constant voltage of VZCDM

VHV, VAUX, VVPO voltages

VOUT output voltage

VREF reference voltage

1000step 1006

Detailed Description

Referring to fig. 1 and 2, fig. 1 is a schematic diagram of aprimary controller 200 applied to a primary side PRI of apower converter 100 according to a first embodiment of the present invention, and fig. 2 is a schematic diagram illustrating a compensationvoltage generating circuit 204 for generating a compensation voltage VCOMP in theprimary controller 200, wherein theprimary controller 200 includes acurrent compensation circuit 202 and a compensationvoltage generating circuit 204, thepower converter 100 is a flyback power converter (flyback power converter), and thecurrent compensation circuit 202 is coupled to an auxiliary winding 103 of the primary side PRI of thepower converter 100 through avoltage dividing circuit 101. As shown in fig. 2, the compensationvoltage generating circuit 204 determines the compensation voltage VCOMP at the pin COMP of theprimary controller 200 by using a peak current IPK, the discharge time TDIS of the secondary side SEC of thepower converter 100, and a reference current IREF. In addition, as shown in fig. 2, the compensationvoltage generating circuit 204 includes a referencecurrent source 2042, aswitch 2044, and a peakcurrent source 2046, wherein the referencecurrent source 2042 is configured to provide a reference current IREF, theswitch 2044 is turned on according to the discharge time TDIS, the peakcurrent source 2046 is configured to provide a peak current IPK, and the coupling relationship among the referencecurrent source 2042, theswitch 2044, and the peakcurrent source 2046 can refer to fig. 2, which is not repeated herein. After the compensation voltage VCOMP is generated, a GATE control signal generating circuit (not shown in fig. 1 and 2) in thepower converter 100 generates a GATE control signal GCS according to the compensation voltage VCOMP to control thepower switch 102 of thepower converter 100 to turn on or off, wherein the GATE control signal GCS is transmitted to thepower switch 102 through the pin GATE of theprimary controller 200, and the peak current IPK is determined by equation (1):

as shown in equation (1), VPK is the peak voltage of the primary side PRI of thepower converter 100, RS is the resistance of thesensing resistor 104 of the primary side PRI of thepower converter 100, and K is a constant.

In addition, as shown in fig. 2, when the compensation voltage VCOMP is stable, equation (2) can be determined according to the charge conservation on the compensation capacitor CCOMP coupled to the pin COMP:

IREF×TS＝IPK×TDIS (2)

as shown in equation (2), TS is the switching period of thepower switch 102. In addition, it should be understood by those skilled in the art that the output current IOUT of the secondary side SEC of thepower converter 100 can be determined by equation (3):

as shown in equation (3), NP is the number of turns of the primary winding 106 of the primary side PRI of thepower converter 100, and NS is the number of turns of the secondary winding 108 of the secondary side SEC of thepower converter 100. Since the sensing voltage VS across thesensing resistor 104 is determined by thesensing resistor 104, the on-time TON of thepower switch 102 and the current IPRI flowing through the primary side PRI of thepower converter 100, the peak voltage VPK of the sensing voltage VS is ideally determined by the sensing voltage VS and the on-time TON of thepower switch 102. However, because of the non-ideality of the sensing voltage VS (wherein the actual value of the sensing voltage VS may refer to the solid line shown in fig. 3 and the ideal value of the sensing voltage VS may refer to the dashed line shown in fig. 3), the actual peak voltage VPK is not equal to the ideal peak voltage VIPK, that is, the peak voltage VPK has an error. In addition, in practice, the discharge time TDIS of the secondary side SEC of thepower converter 100 is not ideal, that is, the start point and the end point of the discharge time TDIS cannot be accurately determined, so that the discharge time TDIS is not equal to the ideal discharge time, that is, the discharge time TDIS also has an error. Therefore, since the peak voltage VPK has an error and the discharge time TDIS also has an error, the output current IOUT actually varies with the output voltage VOUT of the secondary side SEC of the power converter 100 (as shown in fig. 4), where the vertical axis of fig. 4 is the output current IOUT and the horizontal axis of fig. 4 is the input voltage VAC of the primary side PRI of thepower converter 100.

Since the compensation voltage VCOMP is related to the output voltage VOUT and the gate control signal generating circuit can generate the gate control signal GCS to control the on-time TON of thepower switch 102 of thepower converter 100 according to the compensation voltage VCOMP, the on-time TON of thepower switch 102 is related to the output voltage VOUT. Since the on-time TON of thepower switch 102 is related to the output voltage VOUT, and the peak voltage VPK can be determined by the sensing voltage VS and the on-time TON of thepower switch 102, the peak voltage VPK is also related to the output voltage VOUT. In addition, since the discharge time TDIS of the secondary side SEC of thepower converter 100 is related to the on time TON of thepower switch 102, the discharge time TDIS is also related to the output voltage VOUT. Therefore, since the peak voltage VPK and the discharging time TDIS are both related to the output voltage VOUT, as shown in fig. 5, thecurrent compensation circuit 202 can generate a compensation current ICC to thesense resistor 104 according to a dc voltage VDC and an auxiliary voltage VZCD, wherein thecurrent compensation circuit 202 receives the auxiliary voltage VZCD through the pin ZCD of theprimary controller 200, the compensation current ICC flows to thesense resistor 104 through the pin CS of theprimary controller 200 during the on time TON of thepower switch 102, and the dc voltage VDC is related to the voltage VHV at the pin HV of the primary controller 200 (for example, the dc voltage VDC is divided by the voltage VHV). In addition, since the voltage VHV is related to the input voltage VAC, the direct-current voltage VDC is also related to the input voltage VAC. In addition, as shown in fig. 1, since the auxiliary voltage VZCD is related to the voltage VAUX generated by the auxiliary winding 103, the auxiliary voltage VZCD is also related to the output voltage VOUT. In addition, as shown in fig. 1, theprimary controller 200 receives the voltage VAUX through a pin VCC and adiode 110, and generates an operating voltage in theprimary controller 200 according to the voltage VAUX. In addition, as shown in fig. 1, theprimary controller 200 is grounded through a pin GND.

As shown in fig. 5, a Digital-to-Analog Converter (DAC) 2022 in thecurrent compensation circuit 202 can convert the auxiliary voltage VZCD into Digital signals DS1 and DS2, but the present invention is not limited to theDAC 2022 being a two-bit DAC. As shown in fig. 5, anoperational amplifier 20242, annmos transistor 20244 and aresistor 20246 in the compensationcurrent generating unit 2024 can determine a current IS according to the dc voltage VDC; then, a first current mirror composed ofpmos transistors 20248, 20250, 20252 in the compensationcurrent generating unit 2024 generates the compensation current ICC to thesensing resistor 104 according to the current IS and the digital signals DS1, DS 2. In addition, theoperational amplifier 20242, thenmos transistor 20244, theresistor 20246 and thepmos transistors 20248, 20250 and 20252 are coupled with reference to fig. 5, and are not described herein again. In addition, since thecurrent compensation circuit 202 generates the compensation current ICC based on the dc voltage VDC and the auxiliary voltage VZCD as shown in fig. 5, the compensation current ICC is related to both the input voltage VAC and the output voltage VOUT (since the dc voltage VDC is related to the input voltage VAC and the auxiliary voltage VZCD is related to the output voltage VOUT). In addition, as shown in fig. 1, because the compensation current ICC flows to thesensing resistor 104 through the pin CS of theprimary controller 200, the compensation current ICC changes the peak current IPK of the primary side PRI of thepower converter 100, wherein because the compensation current ICC is related to the input voltage VAC and the output voltage VOUT at the same time, the peak current IPK is also related to the input voltage VAC and the output voltage VOUT at the same time.

In addition, since the on-time TON of thepower switch 102 is also larger when the output voltage VOUT is higher, the influence of the error of the on-time TON of thepower switch 102 is smaller. Therefore, as shown in fig. 6, when the output voltage VOUT is higher (i.e., the auxiliary voltage VZCD is higher), the compensation current ICC is smaller, i.e., the compensation current ICC decreases with the increase of the output voltage VOUT. In addition, the present invention is not limited to the circuit architecture of thecurrent compensation circuit 202 in fig. 5, that is, a current compensation circuit that can make the compensation current ICC decrease with the increase of the output voltage VOUT falls into the scope of the present invention. In addition, the present invention is not limited to the compensationcurrent generating unit 2024 generating the compensation current ICC in a digital manner as shown in fig. 6, that is, in another embodiment of the present invention, the compensationcurrent generating unit 2024 generates the compensation current ICC in an analog manner. In addition, after the compensationcurrent generating unit 2024 generates the compensation current ICC to thesensing resistor 104, the relationship between the output current IOUT, the output voltage VOUT, and the input voltage VAC may be referred to fig. 7. As shown in fig. 7, although the curves corresponding to the output current IOUT (corresponding to different output voltages VOUT) are flat and consistent, there is an offset between the curves, wherein the offset is related to the smaller gain of the negative feedback loop of the constant current control in theprimary controller 200.

Equation (3) is that the negative feedback loop based on the constant current control has a sufficiently large gain, so when the negative feedback loop of the constant current control has a small gain, equation (3) must introduce a factor regarding the gain of the negative feedback loop into equation (4):

as shown in equation (4), GCC is the gain of the negative feedback loop. Further, formula (5) can be obtained by substituting formula (1) and formula (2) for formula (4):

as shown in equation (5), when the gain GCC of the negative feedback loop is small and the output voltage VOUT varies, the output current IOUT will vary with the output voltage VOUT, so the output current IOUT can be eliminated by adjusting the reference current IREF to eliminate the influence of the gain GCC of the negative feedback loop on the output current IOUT. In addition, as can also be seen from equation (5), the output current IOUT and the reference current IREF are positively correlated, so the reference current IREF provided by the referencecurrent source 2042 must be variable and vary with the output voltage VOUT of the secondary side SEC of thepower converter 100 to eliminate the offset between the curves.

Referring to fig. 8, fig. 8 is a schematic diagram illustrating the referencecurrent source 2042. As shown in fig. 8, theoperational amplifiers 20422, 20424, thenmos 20426, 20428, thepmos 20430, and theresistor 20432 in the referencecurrent source 2042 determine a first current I1. As shown in fig. 8, a certain voltage vzcm is set according to the maximum value of the operating range of the output voltage VOUT, so that the first current I1 is inversely changed with the auxiliary voltage VZCD, that is, the first current I1 is decreased with the increase of the auxiliary voltage VZCD and the first current I1 is increased with the decrease of the auxiliary voltage VZCD. Since the auxiliary voltage VZCD is positively correlated with the output voltage VOUT, the first current I1 also varies inversely with the output voltage VOUT. Then, a second current mirror formed by thenmos 20428 and thenmos 20434 in the referencecurrent source 2042 can generate a second current I2 according to the first current I1, wherein the ratio of the width-to-length ratio of thenmos 20434 to the width-to-length ratio of thenmos 20428 and the first current I1 can determine the second current I2 according to equation (6), wherein the second current I2 inversely varies with the output voltage VOUT because the first current I1 inversely varies with the output voltage VOUT:

as shown in formula (6), (W/L)₂₀₄₃₄Is the width-to-length ratio of theNMOS transistor 20434, and (W/L)₂₀₄₂₈Is the width-to-length ratio ofnmos transistor 20428.

In addition, as shown in fig. 8, the referencecurrent source 2042 may utilize anoperational amplifier 20436, annmos 20438, aresistor 20440, a reference voltage VREF, and a second current I2 to determine a voltage VVO by equation (7), wherein acapacitor 20442 is used to stabilize the voltage VVO:

VVO＝VREF-(R₂₀₄₄₀×I2) (7)

as shown in formula (7), R₂₀₄₄₀The resistance of theresistor 20440, wherein the voltage VVO increases with the increase of the output voltage VOUT when the output voltage VOUT increases because the second current I2 varies inversely with the output voltage VOUT, that is, the voltage VVO varies positively with the output voltage VOUT.

After the voltage VVO is generated, the referencecurrent source 2042 may generate the reference current IREF by using avoltage converter 20444. Because the voltage VVO varies in the forward direction with the output voltage VOUT, the reference current IREF also varies in the forward direction with the output voltage VOUT. Therefore, the offset shown in fig. 7 will be eliminated because the reference current IREF can be changed in the positive direction of the output voltage VOUT (as shown in fig. 9). Therefore, as shown in fig. 9, theprimary controller 200 can utilize the compensation current ICC generated by thecurrent compensation circuit 202 and the reference current IREF generated by the referencecurrent source 2042 to make the output current IOUT of the secondary side SEC of thepower converter 100 not change with the output voltage VOUT of the secondary side SEC of thepower converter 100. In addition, reference may be made to fig. 8 for the coupling relationship between theoperational amplifiers 20422, 20424, 20436, thenmos 20426, 20428, 20434, 20438, thepmos 20430, theresistors 20432, 20440, thecapacitor 20442 and the vsc, which is not described herein again. In addition, the present invention is not limited to the circuit architecture of the referencecurrent source 2042 in fig. 8, that is, any reference current source that can increase the reference current IREF with the increase of the output voltage VOUT is within the scope of the present invention.

Referring to fig. 1 to 10, fig. 10 is a flowchart illustrating an operation method of a primary controller applied to a primary side of a power converter according to a second embodiment of the present invention. The operation method of fig. 10 is illustrated by using thepower converter 100 and theprimary controller 200 of fig. 1, the compensationvoltage generating circuit 204 of fig. 2, the current compensatingcircuit 202 of fig. 5 and the referencecurrent source 2042 of fig. 8, and the detailed steps are as follows:

step 1000: starting;

step 1002: thecurrent compensation circuit 202 generates a compensation current ICC to thesense resistor 104 of the primary-side PRI of thepower converter 100 according to the dc voltage VDC and the auxiliary voltage VZCD;

step 1004: the compensationvoltage generation circuit 204 generates a compensation voltage VCOMP according to the reference current IREF, the discharge time TDIS of the secondary side SEC of thepower converter 100, and the peak current IPK;

step 1006: the gate control signal generating circuit generates the gate control signal GCS to thepower switch 102 of the primary-side PRI of thepower converter 100 according to the compensation voltage VCOMP, and then jumps back tostep 1002.

Instep 1002, as shown in fig. 5, thecurrent compensation circuit 202 may generate a compensation current ICC to thesensing resistor 104 according to the dc voltage VDC and the auxiliary voltage VZCD, wherein the compensation current ICC flows to thesensing resistor 104 through the pin CS of theprimary controller 200 during the on-time TON of thepower switch 102, and the dc voltage VDC is related to the voltage VHV at the pin HV of theprimary controller 200. In addition, since the voltage VHV is related to the input voltage VAC, the direct-current voltage VDC is also related to the input voltage VAC. In addition, as shown in fig. 1, since the auxiliary voltage VZCD is related to the voltage VAUX generated by the auxiliary winding 103, the auxiliary voltage VZCD is also related to the output voltage VOUT. As shown in fig. 5, the digital-to-analog converter 2022 in thecurrent compensation circuit 202 can convert the auxiliary voltage VZCD into digital signals DS1, DS 2. As shown in fig. 5, theoperational amplifier 20242, thenmos transistor 20244 and theresistor 20246 in the compensationcurrent generating unit 2024 can determine the current IS according to the dc voltage VDC; then, the first current mirror composed of thepmos transistors 20248, 20250, 20252 in the compensationcurrent generating unit 2024 can generate the compensation current ICC to thesensing resistor 104 according to the current IS and the digital signals DS1, DS 2. In addition, since thecurrent compensation circuit 202 generates the compensation current ICC based on the dc voltage VDC and the auxiliary voltage VZCD as shown in fig. 5, the compensation current ICC is related to both the input voltage VAC and the output voltage VOUT (since the dc voltage VDC is related to the input voltage VAC and the auxiliary voltage VZCD is related to the output voltage VOUT). In addition, as shown in fig. 1, because the compensation current ICC flows to thesensing resistor 104 through the pin CS of theprimary controller 200, the compensation current ICC changes the peak current IPK of the primary side PRI of thepower converter 100, wherein because the compensation current ICC is related to the input voltage VAC and the output voltage VOUT at the same time, the peak current IPK is also related to the input voltage VAC and the output voltage VOUT at the same time.

In addition, since the on-time TON of thepower switch 102 is also larger when the output voltage VOUT is higher, the influence of the error of the on-time TON of thepower switch 102 is smaller. Therefore, as shown in fig. 6, when the output voltage VOUT is higher (i.e., the auxiliary voltage VZCD is higher), the compensation current ICC is smaller, i.e., the compensation current ICC decreases with the increase of the output voltage VOUT. In addition, after the compensationcurrent generating unit 2024 generates the compensation current ICC to thesensing resistor 104, the relationship between the output current IOUT, the output voltage VOUT, and the input voltage VAC may be referred to fig. 7. As shown in fig. 7, although the curves corresponding to the output current IOUT (corresponding to different output voltages VOUT) are flat and consistent, there is an offset between the curves, wherein the offset is related to the smaller gain of the negative feedback loop of the constant current control in theprimary controller 200.

Instep 1004, as shown in fig. 8, theoperational amplifiers 20422, 20424, thenmos 20426, 20428, thepmos 20430, and theresistor 20432 in the referencecurrent source 2042 determine the first current I1. As shown in fig. 8, the constant voltage vzcm is set according to the maximum value of the operating range of the output voltage VOUT, so the first current I1 is inversely changed with the auxiliary voltage VZCD, that is, the first current I1 is decreased with the increase of the auxiliary voltage VZCD and the first current I1 is increased with the decrease of the auxiliary voltage VZCD. Since the auxiliary voltage VZCD is positively correlated with the output voltage VOUT, the first current I1 also varies inversely with the output voltage VOUT. Then, the second current mirror formed by thenmos 20428 and thenmos 20434 in the referencecurrent source 2042 can generate a second current I2 according to the first current I1, wherein the ratio of the width-to-length ratio of thenmos 20434 to the width-to-length ratio of thenmos 20428 and the first current I1 can determine the second current I2 by equation (6), and the second current I2 also inversely varies with the output voltage VOUT because the first current I1 inversely varies with the output voltage VOUT. In addition, as shown in fig. 8, the referencecurrent source 2042 may determine the voltage VVO by equation (7) using theoperational amplifier 20436, thenmos 20438, theresistor 20440, the reference voltage VREF, and the second current I2. Since the second current I2 varies inversely with the output voltage VOUT, when the output voltage VOUT increases, the voltage VVO increases with the increase of the output voltage VOUT, that is, the voltage VVO varies positively with the output voltage VOUT. Therefore, after the voltage VVO is generated, the referencecurrent source 2042 can generate the reference current IREF by using thevoltage converter 20444. Because the voltage VVO varies in the forward direction with the output voltage VOUT, the reference current IREF also varies in the forward direction with the output voltage VOUT. Then, as shown in fig. 2, the compensationvoltage generating circuit 204 can determine the compensation voltage VCOMP at the pin COMP of theprimary controller 200 by using the peak current IPK, the discharge time TDIS of the secondary side SEC of thepower converter 100, and the reference current IREF.

Instep 1006, after the compensation voltage VCOMP is generated, the gate control signal generating circuit (not shown in fig. 1 and 2) generates the gate control signal GCS to control thepower switch 102 of thepower converter 100 to turn on or off according to the compensation voltage VCOMP.

Therefore, as shown in fig. 9, after the compensation current ICC and the reference current IREF are generated, theprimary controller 200 can make the output current IOUT not change with the output voltage VOUT.

In summary, the primary controller applied to the primary side of the power converter and the operating method thereof disclosed by the present invention utilize the compensation current generated by the current compensation circuit and varying in a reverse direction with respect to the output voltage and the reference current generated by the reference current source and varying in a forward direction with respect to the output voltage to make the output current not vary with the output voltage. Therefore, compared with the prior art, the compensation current and the reference current are related to the output voltage, so the invention can effectively eliminate the influence of the output voltage on the output current.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (18)

Translated fromChinese

1.一种应用于电源转换器的一次侧的初级控制器，其特征在于包含：1. A primary controller applied to the primary side of a power converter, characterized by comprising:一高压引脚，用以接收一整流电压，其中所述整流电压和一输入电压有关；a high-voltage pin for receiving a rectified voltage, wherein the rectified voltage is related to an input voltage;一电流补偿电路，用以根据一直流电压和一辅助电压，产生一补偿电流至所述一次侧的传感电阻，其中所述辅助电压和所述电源转换器的二次侧的输出电压有关，所述补偿电流会改变所述一次侧的峰值电压，且所述直流电压是根据所述整流电压产生；及a current compensation circuit for generating a compensation current to the sensing resistor of the primary side according to a DC voltage and an auxiliary voltage, wherein the auxiliary voltage is related to the output voltage of the secondary side of the power converter, the compensation current changes the peak voltage of the primary side, and the DC voltage is generated according to the rectified voltage; and一补偿电压产生电路，耦接于所述电流补偿电路，用以根据一参考电流、所述二次侧的放电时间和一峰值电流，产生一补偿电压，其中所述参考电流会随所述电源转换器的二次侧的输出电压改变；a compensation voltage generating circuit coupled to the current compensation circuit for generating a compensation voltage according to a reference current, a discharge time of the secondary side and a peak current, wherein the reference current varies with the power supply The output voltage of the secondary side of the converter changes;其中所述补偿电流和所述参考电流是用以使所述电源转换器的二次侧的输出电流不随所述电源转换器的二次侧的输出电压改变。The compensation current and the reference current are used to make the output current of the secondary side of the power converter not change with the output voltage of the secondary side of the power converter.2.如权利要求1所述的初级控制器，其特征在于：所述电源转换器是一反激式电源转换器。2. The primary controller of claim 1, wherein the power converter is a flyback power converter.3.如权利要求1所述的初级控制器，其特征在于：所述补偿电流会随所述输出电压的增加而降低。3. The primary controller of claim 1, wherein the compensation current decreases as the output voltage increases.4.如权利要求1所述的初级控制器，其特征在于：所述参考电流会随所述输出电压的增加而增加。4. The primary controller of claim 1, wherein the reference current increases as the output voltage increases.5.如权利要求1所述的初级控制器，其特征在于：所述输出电流有关于所述二次侧的放电时间和所述峰值电压。5. The primary controller of claim 1, wherein the output current is related to the discharge time of the secondary side and the peak voltage.6.如权利要求1所述的初级控制器，其特征在于：所述峰值电流和所述峰值电压有关。6. The primary controller of claim 1, wherein the peak current is related to the peak voltage.7.如权利要求1所述的初级控制器，其特征在于：所述二次侧的放电时间和所述峰值电压会随所述电源转换器的二次侧的输出电压改变。7. The primary controller of claim 1, wherein the discharge time of the secondary side and the peak voltage vary with the output voltage of the secondary side of the power converter.8.如权利要求1所述的初级控制器，其特征在于：所述电流补偿电路通过一分压电路耦接于所述电源转换器的一次侧的辅助绕组。8 . The primary controller of claim 1 , wherein the current compensation circuit is coupled to the auxiliary winding of the primary side of the power converter through a voltage divider circuit. 9 .9.如权利要求1所述的初级控制器，其特征在于：所述直流电压和所述电源转换器的一次侧的输入电压有关。9. The primary controller of claim 1, wherein the DC voltage is related to the input voltage of the primary side of the power converter.10.如权利要求1所述的初级控制器，其特征在于另包含：10. The primary controller of claim 1, further comprising:一栅极控制信号产生电路，用以根据所述补偿电压产生一栅极控制信号至所述电源转换器的一次侧的功率开关，其中所述栅极控制信号是用以控制所述功率开关的开启与关闭。a gate control signal generating circuit for generating a gate control signal to the power switch of the primary side of the power converter according to the compensation voltage, wherein the gate control signal is used to control the power switch On and off.11.一种应用于电源转换器的一次侧的初级控制器的操作方法，其中所述初级控制器包含一高压引脚、一电流补偿电路、一补偿电压产生电路和一栅极控制信号产生电路，所述操作方法的特征在于包含：11. An operation method of a primary controller applied to a primary side of a power converter, wherein the primary controller comprises a high voltage pin, a current compensation circuit, a compensation voltage generating circuit and a gate control signal generating circuit , the operating method is characterized by comprising:所述高压引脚接收一整流电压，其中所述整流电压和一输入电压有关；所述电流补偿电路根据一直流电压和一辅助电压，产生一补偿电流至所述一次侧的传感电阻，其中所述辅助电压和所述电源转换器的二次侧的输出电压有关，所述补偿电流会改变所述一次侧的峰值电压，The high voltage pin receives a rectified voltage, wherein the rectified voltage is related to an input voltage; the current compensation circuit generates a compensation current to the sensing resistor of the primary side according to the DC voltage and an auxiliary voltage, wherein The auxiliary voltage is related to the output voltage of the secondary side of the power converter, and the compensation current will change the peak voltage of the primary side,且所述直流电压是根据所述整流电压产生；and the DC voltage is generated according to the rectified voltage;所述补偿电压产生电路根据一参考电流、所述二次侧的放电时间和一峰值电流，产生一补偿电压，其中所述参考电流会随所述电源转换器的二次侧的输出电压改变；及The compensation voltage generating circuit generates a compensation voltage according to a reference current, a discharge time of the secondary side and a peak current, wherein the reference current varies with the output voltage of the secondary side of the power converter; and所述栅极控制信号产生电路根据所述补偿电压产生一栅极控制信号至所述电源转换器的一次侧的功率开关，其中所述栅极控制信号是用以控制所述功率开关的开启与关闭；The gate control signal generating circuit generates a gate control signal to the power switch of the primary side of the power converter according to the compensation voltage, wherein the gate control signal is used to control the turn-on and turn-on of the power switch. closure;其中所述补偿电流和所述参考电流是用以使所述电源转换器的二次侧的输出电流不随所述电源转换器的二次侧的输出电压改变。The compensation current and the reference current are used to make the output current of the secondary side of the power converter not change with the output voltage of the secondary side of the power converter.12.如权利要求11所述的操作方法，其特征在于：所述补偿电流会随所述输出电压的增加而降低。12. The operating method of claim 11, wherein the compensation current decreases as the output voltage increases.13.如权利要求11所述的操作方法，其特征在于：所述参考电流会随所述输出电压的增加而增加。13. The operating method of claim 11, wherein the reference current increases as the output voltage increases.14.如权利要求11所述的操作方法，其特征在于：所述输出电流有关于所述二次侧的放电时间和所述峰值电压。14. The operating method of claim 11, wherein the output current is related to the discharge time of the secondary side and the peak voltage.15.如权利要求11所述的操作方法，其特征在于：所述峰值电流和所述峰值电压有关。15. The operating method of claim 11, wherein the peak current is related to the peak voltage.16.如权利要求11所述的操作方法，其特征在于：所述二次侧的放电时间和所述峰值电压会随所述电源转换器的二次侧的输出电压改变。16. The operating method of claim 11, wherein the discharge time of the secondary side and the peak voltage vary with the output voltage of the secondary side of the power converter.17.如权利要求11所述的操作方法，其特征在于：所述电流补偿电路通过一分压电路耦接于所述电源转换器的一次侧的辅助绕组。17 . The operating method of claim 11 , wherein the current compensation circuit is coupled to the auxiliary winding of the primary side of the power converter through a voltage divider circuit. 18 .18.如权利要求11所述的操作方法，其特征在于：所述直流电压和所述电源转换器的一次侧的输入电压有关。18. The operating method of claim 11, wherein the DC voltage is related to the input voltage of the primary side of the power converter.

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