KR101564446B1 - Power supply device - Google Patents

Abstract

The present invention relates to a switching power supply device having a switch for switching an input power source, a primary winding for receiving an input power by the switching, and a secondary winding electromagnetically coupled to the primary winding to receive power from the primary winding, An insulated converter unit insulated from a secondary side region where the secondary winding and the primary side region are located; A voltage feedback unit having a secondary winding electromagnetically coupled with the secondary winding and a diode connected in series with the secondary winding, the voltage feedback unit located in the primary side region; And a control unit for controlling the switch based on at least one of first voltage information at an anode end of the diode and second voltage information at a cathode end of the diode.

Description

POWER SUPPLY DEVICE

The present invention relates to a PSR type power supply.

Recently, mobile devices such as smart phones and tablet PCs are attracting much attention. Therefore, a lot of research and development on an adapter device for charging the battery of the mobile device is under way. The adapter device must be able to stably supply the output power required by the devices connected thereto. In addition, in order to maximize the portability, the adapter device is required to be reduced in size and weight.

On the other hand, the adapter device has different regulations and power specifications to be satisfied according to the power specifications of each device.

Since there is no power factor and harmonic regulation in the battery charging system of less than 75W class, the present battery charging system has the flyback converter that can configure the circuit with the smallest number of the insulated DC converters It is widely adopted.

However, as standby power regulation has been gradually strengthened, studies on an insulated power supply device of a PSR (Primary Side Regulation) type that indirectly controls the output power from the primary side are being actively researched.

In the secondary side regulation (SSR) system which directly controls the output power from the secondary side, a photocoupler (Photo Coupler) for transmitting the control signal to the primary side and a bias resistor There is a difficulty in satisfying the standby power regulation.

The power supply system of the PSR system is advantageous for satisfying the standby power as compared with the power supply system of the SSR system because the secondary control unit can be omitted. In addition, the PSR type power supply device has a high effect of reducing the number of elements and reducing the volume.

Due to these advantages, there is a growing interest in PSR type power supplies and various studies are underway.

However, since the PSR type insulated power supply device indirectly controls the output voltage through the auxiliary winding provided on the primary side without directly detecting the secondary side voltage, it is difficult to accurately control the output voltage when the load fluctuates.

That is, the PSR type insulated power supply has poor output voltage regulation characteristics due to variations in output load. For example, as the energy stored in the parasitic inductance component of the transformer varies, the coupling degree of the transformer changes. Therefore, the output voltage of the auxiliary winding, which is substantially controlled in the PSR type insulated power supply, is accurately controlled. However, The output voltage at which the indirect control is performed becomes low.

Korean Patent No. 10-0973758

The present specification is intended to provide a PSR-type insulated power supply capable of accurately controlling an output voltage.

The present specification is intended to provide a control method of a PSR-type insulated power supply apparatus applicable to CCM driving.

According to an aspect of the present invention, a power supply apparatus includes a switch for switching an input power source, a primary winding for receiving input power by the switching, and a secondary winding for receiving power from the primary winding by being electromagnetically coupled to the primary winding, An insulated converter unit insulated from the primary side region in which the switch and the primary winding are located and the secondary side region in which the secondary winding is located; A voltage feedback unit having a secondary winding electromagnetically coupled with the secondary winding and a diode connected in series with the secondary winding, the voltage feedback unit located in the primary side region; And a control unit for controlling the switch based on at least one of first voltage information at an anode terminal of the diode and second voltage information at a cathode terminal of the diode.

The control unit may detect the first voltage information and the second voltage information after an elapse of a sensing waiting time from the switch-off time of the switch.

The control unit may control the switch based on a larger one of the first voltage information and the second voltage information.

The isolation converter unit may further include an output diode connected to the secondary winding.

The control unit detects the conduction time of the output diode from the first voltage information and the second voltage information, and determines whether the first voltage information or the second voltage information is any one of the first voltage information and the second voltage information based on the sensing waiting period and the diode conduction time Can be selected as the control information.

The control unit may select the first voltage information as control information when the output diode conduction time is longer than the sensing waiting period.

The power supply device may select the first voltage information as control information when the level of the first voltage information corresponds to a predetermined range.

The power supply device may select the second voltage information as control information when the level of the first voltage information is out of a preset range.

It is possible to provide a PSR type insulated power supply device capable of accurately controlling the output voltage by the disclosure of the present specification.

The disclosure of the present specification can provide a method of controlling an insulated power supply apparatus of a PSR type which is applicable to CCM driving.

1 is a configuration diagram of a flyback DC / DC converter of a PSR type according to an embodiment of the present invention.
2 is a view showing a waveform of a main part of the PSR insulation converter.
3 is a view showing the waveform of the main part of the PSR insulation converter in normal operation.
4 is a view showing the waveform of the main portion of the PSR insulation converter when the output load current is increased.
5 is a diagram showing the waveform of the main portion of the PSR insulation converter when the output load current is reduced.
6 is a waveform diagram of a main part of a PSR insulation converter in a burst mode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. In addition, it should be noted that the attached drawings are only for easy understanding of the embodiments disclosed in the present specification, and should not be construed as limiting the technical idea disclosed in the present specification by the attached drawings.

On the other hand, for convenience of explanation, the configuration of the power supply apparatus will be described with reference to a flyback converter in this specification.

However, the configuration according to the embodiments described herein may be applied to a forward converter, a half-bridge converter, a full-bridge converter, a push-pull converter, a resonant converter, Will be readily apparent to those skilled in the art.

1 is a configuration diagram of a flyback DC / DC converter of a PSR type according to an embodiment of the present invention.

Referring to FIG. 1, the flyback DC / DC converter of the PSR type may include an input power source Vin, an insulation converter unit 100, a voltage feedback unit 200, and a control unit 300.

The input power supply unit (Vin) may provide input power to the insulated converter unit (100).

The insulated converter unit 100 includes a switch M ₁ for switching an input power source, a primary winding Np for receiving input power by switching, a primary coil Np for electromagnetic coupling from the primary winding Np, And a secondary winding Ns that receives power.

The region where the switch M ₁ and the primary winding Np are positioned is defined as a primary side region and the region where the secondary winding Ns is positioned is defined as a secondary side region. The primary side region and the secondary side region may be insulated.

Specifically, the switch M ₁ is controlled by a PWM (Pulse Width Modulation) method or a PFM (Pulse Frequency Modulation) method, and the supply of the primary voltage Vpri can be controlled.

The transformer composed of the primary winding Np and the secondary winding Ns converts the primary voltage Vpri to the secondary voltage Vsec according to the turns ratio of the primary winding Np and the secondary winding Ns can do. The transformer is equivalently connected to the primary winding Np in parallel and includes a magnetizing inductor component L _M indicating the magnetization of the magnetic core and a magnetic flux And a leakage inductor component L _lk that is located on the primary current (I in) path by leakage of the leakage inductor component L _lk .

An output diode D1 for rectifying the secondary voltage Vsec and an output capacitor C1 for smoothing the voltage through the output diode D1 may be provided on the output side of the secondary winding Ns.

The voltage feedback unit 200 includes an auxiliary winding Nt electromagnetically coupled with the secondary winding Ns, an auxiliary diode D2 connected in series with the auxiliary winding Nt, an auxiliary capacitor Cs connected in parallel with the auxiliary winding Nt, (C2). Meanwhile, the voltage feedback unit 200 may be located in the primary side region.

Meanwhile, the voltage feedback unit 200 may obtain voltage information according to the turns ratio of the secondary winding Ns and the auxiliary winding Nt.

The control unit 300 controls the auxiliary diode D2 based on at least one of the first voltage information V1 at the anode terminal of the auxiliary diode D2 and the second voltage information V2 at the cathode terminal of the auxiliary diode D2. The switch M ₁ can be controlled.

Specifically, the controller 300 may control the switch M ₁ based on input voltage information Vin_sen, input current information Iin_sen, and output voltage information V1 or V2.

For example, the controller 300 predicts output current information Io based on the input voltage information Vin_sen, input current information Iin_sen, and output voltage information V1 or V2, and controls the switch M ₁ can do.

That is, since the energy conservation law is applied between the input power Pin and the output power Po of the insulation converter, the input power Pin and the output power Po satisfy the following relational expression.

(1)

Pin = Po

Here, Pin denotes input power and Po denotes output power.

(2)

Vin × Iin = Vo × Io

Herein, Vin denotes input voltage information, Iin denotes input current information, Vo denotes output voltage information, and Io denotes output current information.

Therefore, the output current information Io can be detected by the following equation.

Io = (Vin x Iin) / Vo

That is, the controller 300 may obtain the output current information Io based on the output voltage information Vo, the input current information Iin, and the input voltage information Vin.

The power supply device of the above-described type is applicable in CCM (Continuous Current Mode).

2 is a view showing a waveform of a main part of the PSR insulation converter.

1 and 2, the controller 300 detects the first voltage information V1 after the elapse of the sensing waiting time from the switch-off time of the switch M ₁ , and outputs the second voltage information V2 Can be detected. At this time, the sensing wait time may be preset by the user, for example, may be a sufficient time for the ringing phenomenon of the first voltage information or the second voltage information to disappear.

In addition, the controller may control the switch based on a larger one of the first voltage information (V1) and the second voltage information (V2).

2 (a) is a diagram showing the waveform of the main part of the PSR insulation converter in the CCM mode.

Here, Ts is a period that means one cycle of the switch (M ₁₎ operating, Ton is a switch (M ₁₎ is meant a section which is turned on, and Toff is a switch (M ₁₎ is turned off energy is transmitted to the secondary side .

Assuming that the control unit 300 is controlled by the first voltage information V1 in a state where the output load is increased, the first voltage information V1 is not a constant level, and the energy stored in the parasitic inductance of the transformer is ringing and a voltage higher than the control level is detected. Therefore, the output voltage Vo is controlled to be relatively low.

Therefore, according to an embodiment of the present invention, the controller 300 detects the first voltage information V1 after a sufficient time required for the ringing phenomenon to disappear and detects the second voltage information V2 can do.

At this time, since the second voltage information V2 detected at the sensing time after the elapse of the sensing waiting time is larger than the first voltage information V1, the controller 300 can select the first voltage information as the control information. Here, the control information means a signal used as an input signal of the control unit, among the first voltage information V1 and the second voltage information V2.

FIG. 2 (b) is a diagram showing waveforms of the main portion of the PSR insulation converter in the DCM mode.

Here, Toff_1 the switch (M ₁₎ and is off and the mean period in which the output diode (D1) conducting, Toff_2 is a switch (M ₁₎ and the off-interval means that the output diode (D1) does not conduct, and

Assuming that the control unit 300 is controlled by the first voltage information V1 in a situation where the output load is reduced or in a no-load state, since the time during which the output diode D1 conducts is very short, This is hard.

In this case, however, since the load is small or absent, the energy stored in the parasitic inductance of the transformer is very small, so that the ringing phenomenon does not occur in the voltage information.

In this embodiment, since the first voltage information V1 is very small at the sensing time point and is not suitable for use as a control signal of the control unit, the controller 300 may generate second voltage information V2 that is larger than the first voltage information V1 Can be selected as the control information.

That is, the control unit 300 detects the first voltage information V1 and detects the second voltage information V2 after the elapse of the sensing waiting time from the switching-off time of the switch M ₁ , It is possible to obtain a constant output voltage regardless of the load variation by controlling the switch based on a larger one of the voltage information V1 and the second voltage information V2.

3 is a view showing the waveform of the main part of the PSR insulation converter in normal operation.

FIG. 3 shows the waveform of the main portion of the PSR insulation converter at the time of output voltage detection under a constant load condition ensuring normal operation.

Referring to FIGS. 1 and 3, the average current of the current I _D flowing in the secondary side diode D 1 in the flyback converter is equal to the average of the output current I _O supplied to the load. The voltage Vo × Nt / Ns applied to the voltage feedback unit 200 may be determined by the output voltage Vo and the auxiliary winding ratio Nt / Ns.

Therefore, the controller 300 can indirectly recognize and control the secondary output voltage Vo through the voltage applied to the voltage feedback unit 200. [

According to an embodiment of the present invention, the controller 300 may detect the conduction time of the output diode from the first voltage information and the second voltage information. Here, the period indicated by Toff may be the conduction time of the output diode.

Also, the controller 300 may select one of the first voltage information and the second voltage information as control information based on the sensing waiting period and the diode conduction time.

More specifically, the control unit may select the first voltage information (V1) as control information when the output diode conduction time is longer than the sensing waiting period (a).

3, there is little difference between the first voltage information V1 and the second voltage information V2.

4 is a view showing the waveform of the main portion of the PSR insulation converter when the output load current is increased.

FIG. 4 shows a case where the PSR insulation converter operates normally under the constant load condition shown in FIG. 3, and the output load current suddenly increases.

When the output load current suddenly increases, the energy stored in the leakage inductance of the secondary side of the transformer increases, and the ringing of the first voltage information V1 is increased by this energy. At this time, the energy Vx due to the increased ringing is stored in the capacitor C2 of the voltage feedback unit 200, which can increase the second voltage information V2.

Therefore, for accurate output voltage detection, the transformer needs to be designed to have low secondary leakage inductance. In this case, variations of the first voltage information V1 and the second voltage information V2 can be reduced.

In addition, when the capacity of the capacitor C2 of the voltage feedback unit 200 is designed to be appropriately small, the energy Vx due to ringing can be appropriately consumed.

That is, even if the energy Vx due to ringing is largely generated, variations in the first voltage information V1 and the second voltage information V2 can be reduced by the leakage inductance value and the capacitance capacity.

5 is a diagram showing the waveform of the main portion of the PSR insulation converter when the output load current is reduced.

The output diode D1 is sufficiently conducted in accordance with the amount of the load current so that accurate detection can be performed by the first voltage information V1 of the voltage feedback unit 200 and the output load current Io can be reduced. Referring to FIGS. 1 and 5, since the load current is small, the conduction time of the output diode D1 can be reduced.

In this embodiment, when the output diode conduction time is longer than the sensing standby period, the controller 300 may select the first voltage information V1 as control information.

6 is a waveform diagram of a main part of a PSR insulation converter in a burst mode.

6 shows a detection waveform of the output voltage at an output current Io under a no-load or constant-load condition (for example, a predetermined Burst mode level).

When the output load is unloaded, there is no energy transferred from the transformer primary to the secondary, and thus the power supply can be controlled in burst mode to prevent an increase in the output voltage Vo.

In the burst mode, the load current Io contains only very small current components due to parasitic components in the circuit, and therefore the conduction time of the output diode D1 is very short.

In this case, since it is difficult to detect the first voltage information V1 of the voltage feedback unit 300, the second voltage information V2 may be selected as the control information in this embodiment.

That is, in the present embodiment, since the output diode conduction time is shorter than the sensing standby period, the controller 300 can select the second voltage information V2 as control information.

On the other hand, in this embodiment, since the load current is very small, the ringing due to the leakage inductance hardly occurs. Accordingly, the levels of the first voltage information V1 and the second voltage information V2 may be substantially similar.

According to another embodiment of the present invention, when it is impossible for the controller 300 to detect the first voltage information V1 at the sensing time, the controller 300 controls the second voltage information V2 to be the control information .

For example, the controller 300 sets a predetermined level for selecting the first voltage information V1 as the control information, and when the level of the first voltage information V1 falls within the predetermined level, The voltage information V1 can be selected as the control information.

The controller 300 may select the second voltage information V2 as the control information when the level of the first voltage information V1 does not fall within the predetermined level range.

As described above, when the leakage inductance is very small and the capacitance of the auxiliary capacitor C2 is much smaller than the capacitance of the output capacitor C1, the levels of the first voltage reference V1 and the second voltage information V2 are almost similar.

However, when the controller 300 enters the burst mode, the controller 300 does not recognize the first voltage information V1. Therefore, the controller 300 recognizes the second voltage information V2 by the above- .

According to the present embodiment, the control unit 300 can stably control the output voltage in the entire region according to the load variation.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the particular forms disclosed. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: Insulation converter section
200:
300:

Claims (8)

A switch for switching an input power source, a primary winding receiving an input power by the switching, and a secondary winding electromagnetically coupled to the primary winding to receive power from the primary winding, wherein the switch and the primary winding An insulation converter unit insulated from a secondary side region where the secondary side winding and the secondary side winding are located;
A voltage feedback unit having a secondary winding electromagnetically coupled with the secondary winding and a diode connected in series with the secondary winding, the voltage feedback unit located in the primary side region; And
Wherein the control unit controls the switch based on at least one of the first voltage information at the anode end of the diode and the second voltage information at the cathode end of the diode, and after elapse of the sensing waiting time from the switch- 1 voltage information and second voltage information. delete The apparatus of claim 1,
And controls the switch based on a larger one of the first voltage information and the second voltage information. The battery pack according to claim 1,
And an output diode coupled to the secondary winding. 5. The apparatus of claim 4,
Detecting conduction time of the output diode from the first voltage information and the second voltage information,
Wherein the control unit selects one of the first voltage information and the second voltage information as the control information based on the sensing waiting period and the diode conduction time. 6. The apparatus of claim 5,
And selects the first voltage information as control information when the output diode conduction time is longer than the sensing waiting period. The method according to claim 1,
And selects the first voltage information as control information when the level of the first voltage information corresponds to a predetermined range. The method according to claim 1,
And selects the second voltage information as control information when the level of the first voltage information is out of a predetermined range.

Images