KR100816842B1 - Power supply using synchronous rectifier - Google Patents

Abstract

A power supply using a synchronous rectifier is provided to reduce switching loss by controlling a switching unit of a converter stage with a fixed duty width of 0.5, thereby improving the efficiency of a circuit. A power supply using a synchronous rectifier includes a rectifying unit(310), a PFC(Power Factor Correction) stage(320), and a converter stage(330). The rectifying unit rectifies input power(Vin) applied from outside to output the rectified input power. The PFC stage is connected to the rectifying unit and receives the rectified input power from the rectifying unit to output PFC voltage(Vb) having a predetermined size. The converter stage is connected to the PFC stage, switches the PFC voltage outputted from the PFC stage with a pulse of a fixed duty width, and constantly outputs output voltage(Vout) by grouping a plurality of pulses into one group and controlling an interval between the groups.

Description

Power supply using synchronous rectifier

1 is a circuit diagram showing a conventional flyback type power supply device.

Figure 2 is a circuit diagram showing a power supply device of a conventional two-stage configuration.

3 is a circuit diagram schematically showing a synchronization power supply according to a first embodiment of the present invention.

4 is a diagram illustrating grouping of first and second switching signals of FIG. 3.

5 is a timing diagram of a synchronization power supply according to a first embodiment of the present invention.

6 is a circuit diagram showing a synchronization power supply according to a second embodiment of the present invention.

7 is a circuit diagram showing a synchronization power supply according to a third embodiment of the present invention.

<Brief description of the main parts of the drawings>

310: rectifier 320: PFC stage

321: PFC voltage output unit 322: PFC control unit

330: converter 331: voltage output unit

331a: switching part 331b: clamping part

332: group control unit 333: switching control unit

The present invention relates to a synchronization power supply, and more particularly, to a synchronization power supply capable of increasing efficiency and miniaturizing a circuit by switching to a fixed duty width of 0.5 to control an output voltage.

In general, a power supply device is a device that converts an input power input from the outside into a voltage of a desired size and is widely used in portable terminals, notebook computers, LCD monitors, and portable electronic products.

Among these power supplies, especially the adapter has a low power and gradually decreases in size, and thus, a two-stage power supply using a flyback method or PFC stage (Power Factor Correction) having the simplest structure is used.

Then, the structure and the problems of the conventional flyback method and the two-stage power supply device will be described in detail with reference to the related drawings.

1 is a circuit diagram showing a conventional flyback type power supply device, and FIG. 2 is a circuit diagram showing a conventional power supply device having a two-stage configuration.

First, as shown in FIG. 1, the conventional flyback type power supply apparatus includes a rectifier 110, a first capacitor C1, a switching means Q1, a controller 120, a transformer T1, and a diode ( D), the second capacitor C2 and the load R _L.

Here, the rectifier 110 rectifies and outputs the input power Vin of an AC component which is composed of a plurality of diodes and is applied from the outside.

The first capacitor C1 has one end connected to the rectifier 110 and the other end connected to ground to receive the rectified input power Vin from the rectifier 110, and receive the applied input power Vin. Output smoothed.

The transformer T1 has a primary side and a secondary side, and receives an input power source Vin smoothed by the first capacitor C1 from the primary side and induces the secondary side to the secondary side. In this case, the magnitude of the input power induced to the secondary side may be changed according to the turns ratio of the primary side and the secondary side of the transformer T1.

The switching means Q1 has a drain connected to one end of the primary side of the transformer T1, a gate connected to the controller 120, a source connected to ground, and turned on / off by the controller 120. off) As controlled, the supply of input power induced from the primary side to the secondary side of the transformer T1 is controlled.

The diode D has an anode connected to one end of the secondary side of the transformer T1, a cathode connected to one end of the second capacitor C2 and the load R _L , and the second capacitor C2 is One end is connected to the cathode of the diode (D) and the other end is grounded to charge and smooth the induced power through the transformer (T1).

One end of the load R _L is connected to a contact point between the second capacitor C2 and the diode D and the other end is grounded to output the power charged in the second capacitor C2 as an output voltage Vout. do.

In this case, the control unit 120 receives the output voltage Vout and outputs the output voltage Vout when the output voltage Vout is lower or higher than a predetermined voltage. The switching control signal for controlling the switching means Q1 is outputted so as to be maintained.

The switching means Q1 receiving the switching control signal from the controller 120 is turned on / off by the switching control signal to control the input power, thereby converting the output voltage Vout to the same voltage as a preset voltage. You can print

However, the conventional flyback type power supply device having the structure as described above is an input power source because it controls the input power Vin when the output voltage Vout is lower or higher than a predetermined predetermined voltage. If (Vin) is applied at an irregular voltage without maintaining a constant size, any restriction on the input power (Vin) until the input power (Vin) is output to the output voltage (Vout) through the transformer (T1) Since this is applied without damaging the elements provided in the circuit by the irregular input power (Vin), there is a problem that is not suitable for a power supply that requires high power density because the efficiency is not high.

In order to make up for the shortcomings of the conventional flyback type power supply device, a power supply device having a two-stage configuration including a PFC stage for controlling input power and a converter stage for controlling an output voltage is used.

The two-stage power supply device includes a rectifier 210, an EMI stage 220, a PFC stage 230, a PFC controller 235, a capacitor C1, a converter stage 240, a converter controller 245, and a load. Consists of 250.

The rectifier 210 is composed of a plurality of diodes to rectify and output the input power (Vin) applied to the power supply device from the outside.

The EMI terminal 220 is connected to the rectifying unit 210 and removed by outputting the electromagnetic wave included in the input power (Vin) rectified by the rectifying unit 210, and the PFC stage 230 is the EMI terminal 220 When the input power (Vin) is removed from the electromagnetic wave is applied to the input power (Vin) is lower or higher than the predetermined voltage of a predetermined size, it is controlled and outputted, and the input power (Vin) or the PFC stage The PFC controller 235 determines whether the voltage Va output from the 230 is lower or higher than a predetermined voltage.

If the input power Vin or the voltage Va output from the PFC stage 230 is lower than a predetermined voltage, the switching means provided in the PFC stage 230 (not shown). When the duty width of the switching means is increased and the voltage is higher than a predetermined predetermined voltage, the duty width of the switching means is decreased, thereby keeping the voltage Va output from the PFC stage 230 constant. In this case, the capacitor C1 smoothes the voltage Va output from the PFC terminal 230.

The converter stage 240 receives the voltage Va smoothed by the capacitor C1 and outputs an output voltage Vout having a predetermined voltage desired by the user, and is connected to the converter stage 240. The converter controller 245 controls the switching element provided in the converter stage 240 when the output voltage Vout output from the converter stage 240 is lower or higher than a predetermined voltage. Output voltage (Vout) having the output. At this time, reference numeral 250 is a load.

However, the two-stage power supply device is a synchronous rectifier that can operate with high efficiency in the converter stage 240 as the diode breakdown voltage is changed by switching loss and control operation due to variable duty width in a device requiring a high current such as an adapter. It is difficult to apply a synchronous rectifier, and thus there is a problem in that efficiency is lowered.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to continuously control the switching unit of the converter stage to a fixed duty width of 0.5, the output voltage is lower or higher than the predetermined predetermined voltage In this case, a plurality of pulses having a fixed duty width of 0.5 for controlling the switching unit are grouped into one group to control the interval therebetween, thereby providing a synchronization power supply that outputs an output voltage having a constant voltage.

Synchronizing power supply apparatus according to the present invention for achieving the above object, Rectifying unit for rectifying and outputting the input power applied from the outside; A PFC stage connected to the rectifier and receiving an input power rectified by the rectifier to output a PFC voltage having a predetermined magnitude; And switching the PFC voltage output from the PFC terminal to a pulse having a fixed duty width, grouping a plurality of pulses of the pulses into one group, and controlling an interval between the grouped groups. And a converter stage for constantly outputting.

In addition, the synchronization power supply according to the present invention, the PFC stage, the PFC voltage output unit for receiving the input power rectified by the rectifier to output a PFC voltage; And a PFC controller which receives the PFC voltage output from the PFC voltage output unit and controls the PFC voltage output unit so that the PFC voltage is kept constant.

In addition, the synchronization power supply according to the present invention, the PFC voltage output unit, the first switching means for switching the input power rectified by the rectifier; A first inductor configured to flow a constant current by receiving an input power supplied by the first switching means; A second inductor for inducing a current flowing through the first inductor; A first capacitor having one end connected to the first inductor and configured to charge a current output from the first inductor; A first diode having a cathode connected to the drain of the first switching means and a contact of the first inductor, and an anode connected to the other end of the first capacitor; And a first resistor having one end connected to the anode of the first diode and the other end connected to ground.

In the synchronization power supply according to the present invention, the converter stage includes: a voltage output unit for outputting a constant voltage output voltage by switching a PFC voltage output from the PFC stage to a fixed duty width; A group controller for grouping a plurality of pulses of the fixed duty width pulses into one group to maintain the output voltage at a constant size, and outputting a control signal for adjusting the interval between the grouped groups; And a switching control unit connected to the group control unit and the voltage output unit and configured to receive a control signal output from the group control unit and output a corresponding switching signal.

In addition, the synchronization power supply according to the present invention, the voltage output unit, the switching unit connected to the first capacitor, for switching the voltage charged in the first capacitor to a fixed duty width of 0.5; A transformer having a primary side and a plurality of secondary sides, the primary side being connected to the switching unit, and configured to induce a voltage switched by the switching unit to the secondary side; A third inductor connected to the secondary side of the transformer and receiving a voltage induced by the secondary side of the transformer to output a constant current; A clamping unit connected to the third inductor and configured to maintain a constant current flowing through the third inductor; And a second capacitor connected to the third inductor and the clamping unit, and configured to charge an electric current flowing through the third inductor and output an output voltage.

In addition, in the synchronization power supply according to the present invention, the switching unit, the drain is connected to the first end of the first capacitor and the transformer, the source is connected to the other end of the primary side of the transformer, the gate is the switching controller Second switching means connected with the; And third switching means having a drain connected to the other end of the first capacitor, a source connected to a source of the second switching means, and a gate connected to the switching controller.

In addition, in the synchronization power supply according to the present invention, the clamping unit, a third capacitor having one end connected to the contact between the secondary side of the transformer and the third inductor; A second diode having an anode connected to the other end of the third capacitor and a cathode connected to the other end of the third inductor; And a third diode having a cathode connected to the other end of the third capacitor and an anode connected to the ground.

On the other hand, in the synchronization power supply according to the present invention, the PFC voltage output unit, the first inductor for flowing a constant current by receiving the input power rectified by the rectifier; A second inductor for inducing a current flowing through the first inductor; A first switching means connected to one end of the first inductor and a gate connected to the PFC controller to switch a current output from the first inductor; an anode connected to a drain of the first switching means, A first diode having a cathode connected to the converter stage; A first resistor having one end connected to the source of the first switching means and the other end connected to the ground; And a first capacitor having one end connected to the cathode of the first diode and the other end connected to the ground.

In addition, the synchronization power supply according to the present invention, the PFC voltage output unit, the first inductor for flowing a constant current by receiving the input power rectified by the rectifier; A second inductor for inducing a current flowing through the first inductor; First switching means for switching a current output from the first inductor with a drain connected to one end of the first inductor and a gate connected to the PFC controller; A first capacitor having one end connected to the drain of the first switching means; A first diode having an anode connected to the source of the first switching means and a cathode connected to the other end of the first capacitor; And a first resistor having one end connected to the anode of the first diode and the other end connected to ground.

The above objects, features, and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be.

In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Next, a synchronization power supply apparatus according to the first to third embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example  One

3 is a circuit diagram schematically illustrating a synchronization power supply according to a first embodiment of the present invention, FIG. 4 is a diagram illustrating grouping of the first and second switching signals of FIG. 3, and FIG. 5 is a first diagram of the present invention. A timing diagram of a synchronization power supply according to an embodiment.

First, as shown in FIG. 3, the synchronization power supply apparatus according to the first embodiment of the present invention includes a rectifier 310, a PFC stage 320, and a converter stage 330.

The rectifying unit 310 is composed of a plurality of diodes to rectify and output the input power (Vin) of the AC component applied from the outside.

The PFC stage 320 includes a PFC voltage output unit 321 and a PFC control unit 322, is connected to the rectifier 310, and applies the input power Vin rectified by the rectifier 310. It receives the PFC voltage (Vb) of a certain size.

The PFC voltage output unit 321 may include first switching means Q1, first and second inductors L1 and L2, a first capacitor C1, and a first resistor R1. The input power Vin, rectified by 310, is applied to output the PFC voltage Vb.

Here, the first switching means Q1 has a drain connected to the rectifier 310, a source connected to the first inductor L1, and a gate connected to the PFC controller 322 so that the PFC controller 322 is connected. As controlled by the on / off, the input power (Vin) rectified by the rectifier 310 is switched to output.

One end of the first inductor L1 is connected to the first switching means Q1 and the other end is connected to one end of the first capacitor C1 and is switched by the first switching means Q1. The power (Vin) is applied to flow a constant current.

One end of the second inductor L2 is connected to the ground, the other end thereof is connected to the PFC controller 322, and the second inductor L2 is disposed to be adjacent to the first inductor L1 to induce a current flowing through the first inductor L1. Receive.

One end of the first capacitor C1 is connected to the first inductor L1, the other end is connected to the first resistor R1, and charges a current flowing through the first inductor L1.

The first diode D1 has a cathode connected to a contact point between the source of the first switching means Q1 and the first inductor L1 and an anode of the first capacitor C1 and the first resistor R1. The first resistor R1 is connected to a contact point, and one end of the first resistor R1 is connected to the anode of the first diode D1 and the other end thereof is grounded.

The PFC controller 322 may include a PFC voltage Vb charged in the first capacitor C1, a current I ₁ flowing through the second inductor L2, and a current I flowing through the first diode D1. ₀ ) and the input power Vin rectified by the rectifier 310, and when the input power Vin and the PFC voltage Vb are lower or higher than a predetermined voltage, the PFC In order to output the voltage Vb as a PFC voltage Vb of a predetermined magnitude, a first switching signal q1 for controlling on / off of the first switching means Q1 is output.

If the input power Vin and the PFC voltage Vb rectified by the rectifier 310 are lower than a preset voltage, the PFC voltage Vb may be maintained at a predetermined voltage. The PFC controller 321 outputs a first switching signal q1 for widening the duty width of the first switching means Q1.

At this time, the first switching means Q1 receives the first switch signal q1 and is turned on for a longer time than before to pass the input power Vin, thereby charging the PFC voltage charged in the first capacitor C1 ( The size of Vb) may be increased to maintain the same voltage as a predetermined voltage.

In addition, when the rectified input power Vin and the PFC voltage Vb charged in the first capacitor C1 are higher than a preset voltage, the PFC voltage Vb may be kept constant and output. The controller 321 outputs a first switching signal q1 for narrowing the duty width of the first switching means Q1.

The first switching means Q1 receives a first switching signal q1 for narrowing the duty width to cut off the input power Vin, thereby reducing the magnitude of the PFC voltage Vb so as to be preset. It can be maintained at the same voltage as a constant voltage.

The converter stage 330 includes a voltage output unit 331, a group controller 332, and a switching controller 333.

The voltage output unit 331 includes a switching unit 331a, second and third capacitors C2 and C3, a transformer T1, second and third resistors R2 and R3, and fourth and fifth switching. Means Q4, Q5, a third inductor L3, and a clamping part 331b, and switching the PFC voltage Vb output from the PFC stage 320 to a fixed duty width so as to output a constant magnitude of output voltage ( Outputs Vout). In this case, the fixed duty width preferably has a fixed duty width of 0.5 to switch the switching unit 331a with high efficiency.

The switching unit 331a is composed of second and third switching means Q2 and Q3 and is turned on / off by the second and third switching signals q2 and q3 applied by the switching control unit 333. The voltage Vb applied from the input terminal 320 is controlled.

The second switching means Q2 has a drain connected to one end of the first capacitor C1, a source connected to a source of the third switching means Q3, and a gate connected to the switching controller 333. On / off control is performed by the second switching signal q2 applied from the switching controller 333.

The third switching means Q3 has a drain connected to the first resistor R1 and a gate connected to the switching controller 333 to be applied by the third switching signal q applied from the switching controller 333. On / off control.

One end of the third capacitor C3 is connected to the drain of the second switching means Q2 and the other end thereof is connected to one end of the transformer T1 to switch the voltage applied by the second switching means Q2. Smoothing is supplied to the transformer T1.

The transformer T1 has a primary side Np and a plurality of secondary sides Ms1 to Ms4, and receives a voltage smoothed by the third capacitor C3 from the primary side Np to receive the secondary side Ms1 ˜. Ms4). At this time, when the voltage is induced to the secondary side Ms1 to Ms4 of the transformer T1, the voltage is induced to the secondary side Ms2 and applied to the gate of the fourth switching means Q4 through the second resistor R2. The fourth switching means Q4 is turned on by the voltage to be supplied, and the voltage supplied from the primary side to the secondary side Ms1 is induced.

In addition, the second switching means Ms3 of the transformer T1 is driven by the voltage applied to the gate of the fifth switching means Q5 through the third resistor R3 as the voltage is induced on the secondary side Ms4. As Q5 turns on, the voltage supplied from the primary side to the secondary side Ms3 is induced.

One end of the inductor L3 is connected to one end of the second side Ms1 to Ms4 of the transformer T1, and the other end is connected to one end of the second capacitor C2, and the voltage induced through the transformer T1. To supply a constant current.

One end of the second capacitor C2 is connected to the other end of the third inductor L3, and the other end is grounded to charge energy corresponding to a current applied from the third inductor L3 to output an output voltage Vout. )

The clamping part 331b includes a fourth capacitor C4 and second and third diodes D2 and D3, and controls the current to flow through the third inductor L3 to be maintained.

One end of the fourth capacitor C4 is connected to a contact between the secondary side of the transformer T1 and the third inductor L3, and the second diode D2 has a cathode of the other end of the third inductor L3. A terminal is connected to the other end of the fourth capacitor C4, an anode is connected to the other end of the fourth capacitor C4, a cathode is connected to the other end of the fourth capacitor C4, and an anode is grounded.

The group controller 332 is connected to one end of the second capacitor C2 and the switching controller 333, and receives a predetermined predetermined size by receiving an output voltage Vout output from the second capacitor C2. In order to keep the output voltage Vout constant when the output voltage Vout is lower or higher than the voltage of, as shown in FIG. 4, the gate voltage is applied to each gate to control the switching unit 331a. The switching controller 333 receives a control signal C for grouping a plurality of pulses among the pulses of the second and third switching signals q2 and q3 into one group and controlling the interval between the grouped groups. To pass on.

In addition, the switching control unit 333 is connected to the group control unit 332 and the second and third switching means Q2 and Q3, and the second and third switching have a duty width always having a constant ratio of 0.5. The means Q2 and Q3 are switched, and the second and third switching signals q2 and q3 for adjusting each group interval are output by the control signal C applied from the group controller 332.

In this case, when the output voltage Vout is lower than or higher than a predetermined voltage, the second and third switching signals q2, in order to output the output voltage Vout to the same voltage as a preset voltage, The switching unit 331a is controlled by adjusting the interval between groups of q3).

The switching unit 331a includes second and third switching signals q2 for controlling the second and third switching means Q2 and Q3 by the control signal C applied from the group control unit 332. , q3) is applied to the gates of the second and third switching means Q2, Q3.

In the synchronization power supply apparatus according to the first embodiment of the present invention having the structure as described above, the PFC terminal 320 controls the input power Vin rectified by the rectifier 310 at the PFC terminal 320. The converter stage 330 receives the PFC voltage Vb output from the PFC stage 320 and outputs a predetermined output voltage Vout.

In this case, as shown in FIG. 5, the converter stage 330 switches the PFC voltage Vb to a fixed duty width of 0.5, and the fixed duty of 0.5 when the output voltage Vout is not a constant size. A plurality of pulses having a width are grouped into one group and the output voltage Vout is kept constant and output by controlling the interval between each grouped group.

The second and third switching means Q2 and Q3 controlled at a duty width of 0.5 are always zero-voltage switched, such as 'A', thereby reducing switching losses, thereby improving efficiency of the entire circuit and increasing power density. There is this.

In addition, since the current waveform of the third inductor L3 is not generated except the current ripple due to the effective dead time generated by the leakage inductance of the converter stage 330, the third inductor ( Since the value of L3) can be minimized, the third inductor L3 can be miniaturized, and the size of the entire circuit can be reduced.

Example  2

6 is a circuit diagram showing a synchronization power supply according to a second embodiment of the present invention. However, the description of the same parts as those of the second embodiment of the configuration of the first embodiment will be omitted, and only the configuration that is different from the second embodiment will be described in detail.

As shown in FIG. 6, the synchronization power supply apparatus according to the second embodiment of the present invention includes a rectifier 410, a PFC stage 420, and a converter stage 430.

In this case, the PFC stage 420 includes a PFC voltage output unit 421 and a PFC control unit 422, and the PFC voltage output unit 421 includes first and second inductors L1 and L2, and a first one. The switching terminal Q1 includes a first diode D1, a first resistor R1, and a first capacitor C1.

The first inductor L1 receives an input power Vin rectified by the rectifier 410 to allow a constant current to flow, and the second inductor L2 receives a current flowing through the first inductor L1. Get abandoned.

The first switching means Q1 has a drain connected to one end of the first inductor L1 and a gate connected to the PFC controller 422 to switch the current output from the first inductor L1.

The first diode D1 has an anode connected to the drain of the first switching means Q1, a cathode connected to the converter stage 430, and one end of the first resistor R1 has the first switching means. It is connected to the source of Q1 and the other end is connected to ground.

One end of the first capacitor C1 is connected to the cathode of the first diode and the other end thereof is grounded.

Example  3

7 is a circuit diagram illustrating a synchronization power supply according to a third embodiment of the present invention.

First, as shown in FIG. 7, the synchronization power supply apparatus according to the third embodiment of the present invention includes a rectifier 510, a PFC stage 520, and a converter stage 530.

At this time, the PFC stage 520 is composed of a PFC voltage output unit 521 and a PFC control unit 522, the PFC voltage output unit 521 is the first and second inductors (L1, L2), the first It consists of a switching means Q1, a first capacitor C1, a first diode D1 and a first resistor R1.

The first inductor L1 receives an input power Vin rectified by the rectifier 510 to allow a constant current to flow, and the second inductor L2 receives a current flowing through the first inductor L1. Get abandoned.

The first switching means Q1 has a drain connected to one end of the first inductor L1 and a gate connected to the PFC controller 422 to switch the current output from the first inductor L1.

One end of the first capacitor C1 is connected to the drain of the first switching means Q1 and the other end thereof is connected to the cathode of the first diode D1.

The first diode D1 has an anode connected to the source of the first switching means Q1, a cathode connected to the other end of the first capacitor C1, and one end of the first resistor R1 It is connected to the anode of the first diode (D1) and the other end is grounded.

The synchronization power supply device according to the second and third embodiments of the present invention having the above configuration operates in the same manner as the synchronization power supply device according to the first embodiment of the present invention described above.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be appreciated that such substitutions, changes, and the like should be considered to be within the scope of the following claims.

As described above, the synchronization power supply according to the present invention, the switching unit of the converter stage to control a fixed duty width of 0.5, when the output voltage is lower or higher than a certain size of voltage, a plurality of pulses for controlling the switching unit By controlling the interval between them by grouping the pulses into a group, the switching loss can be reduced to improve the efficiency and power density of the circuit, and the inductor value can be minimized to reduce the circuit size.

Claims (9)

Rectifying unit for rectifying and outputting the input power applied from the outside; A PFC stage connected to the rectifier and receiving an input power rectified by the rectifier to output a PFC voltage having a predetermined magnitude; And Connected to the PFC stage, the PFC voltage output from the PFC stage is switched to a pulse having a fixed duty width, the plurality of pulses of the pulses are grouped into one group, and the output voltage is constant by controlling the interval between each grouped group. A converter stage for outputting the power; Synchronization power supply comprising a. The method of claim 1, The PFC stage, A PFC voltage output unit receiving the input power rectified by the rectifying unit and outputting a PFC voltage; And A PFC controller which receives the PFC voltage output from the PFC voltage output unit and controls the PFC voltage output unit to maintain the PFC voltage constant; Synchronization power supply comprising a. The method of claim 2, The PFC voltage output unit, First switching means for switching the input power rectified by the rectifier; A first inductor configured to flow a constant current by receiving an input power supplied by the first switching means; A second inductor for inducing a current flowing through the first inductor; A first capacitor having one end connected to the first inductor and configured to charge a current output from the first inductor; A first diode having a cathode connected to the drain of the first switching means and a contact of the first inductor, and an anode connected to the other end of the first capacitor; And A first resistor having one end connected to an anode of the first diode and the other end connected to ground; Synchronization power supply comprising a. The method of claim 1, The converter stage, A voltage output unit configured to switch the PFC voltage output from the PFC stage to a fixed duty width and output an output voltage having a predetermined size; A group controller for grouping a plurality of pulses of the fixed duty width pulses into one group to maintain the output voltage at a constant size, and outputting a control signal for adjusting the interval between the grouped groups; And A switching control unit connected to the group control unit and the voltage output unit and receiving a control signal output from the group control unit and outputting a corresponding switching signal; Synchronization power supply comprising a. The method of claim 4, wherein The voltage output unit, A switching unit connected to the first capacitor and switching the voltage charged in the first capacitor to a fixed duty width of 0.5; A transformer having a primary side and a plurality of secondary sides, the primary side being connected to the switching unit, and configured to induce a voltage switched by the switching unit to the secondary side; A third inductor connected to the secondary side of the transformer and receiving a voltage induced by the secondary side of the transformer to output a constant current; A clamping unit connected to the third inductor and configured to maintain a constant current flowing through the third inductor; And A second capacitor connected to the third inductor and the clamping unit and configured to charge an electric current flowing through the third inductor to output an output voltage; Synchronization power supply comprising a. The method of claim 5, The switching unit, Second switching means having a drain connected to the first capacitor and one end of the transformer, a source connected to the other end of the transformer, and a gate connected to the switching controller; And Third switching means having a drain connected to the other end of the first capacitor, a source connected to a source of the second switching means, and a gate connected to the switching controller; Synchronization power supply comprising a. The method of claim 5, The clamping unit, A third capacitor having one end connected to a contact between a secondary side of the transformer and a third inductor; A second diode having an anode connected to the other end of the third capacitor and a cathode connected to the other end of the third inductor; And A third diode having a cathode connected to the other end of the third capacitor and an anode connected to ground; Synchronization power supply comprising a. The method of claim 2, The PFC voltage output unit, A first inductor receiving a input power rectified by the rectifier to allow a constant current to flow; A second inductor for inducing a current flowing through the first inductor; First switching means for switching a current output from the first inductor with a drain connected to one end of the first inductor and a gate connected to the PFC controller; A first diode having an anode connected to the drain of the first switching means and a cathode connected to the converter stage; A first resistor having one end connected to the source of the first switching means and the other end connected to the ground; And A first capacitor having one end connected to the cathode of the first diode and the other end connected to ground; Synchronization power supply comprising a. The method of claim 2, The PFC voltage output unit, A first inductor receiving a input power rectified by the rectifier to allow a constant current to flow; A second inductor for inducing a current flowing through the first inductor; First switching means for switching a current output from the first inductor with a drain connected to one end of the first inductor and a gate connected to the PFC controller; A first capacitor having one end connected to the drain of the first switching means; A first diode having an anode connected to the source of the first switching means and a cathode connected to the other end of the first capacitor; And A first resistor having one end connected to an anode of the first diode and the other end connected to ground; Synchronization power supply comprising a.

Images