CN101997429B - Global switching power supply and its serial-parallel DC power conversion circuit - Google Patents

Abstract

The invention relates to a global exchange type power supply and a serial-parallel type direct current power supply conversion circuit thereof, wherein the serial-parallel type direct current power supply conversion circuit comprises a transformer, a full-bridge switching circuit, a selector switch and a pulse width modulation controller; the full-bridge switch circuit comprises two parallel first and second switch sets, each active switch set comprises an upper arm active switch and a lower arm active switch which are connected in series, the transformer comprises a primary side coil and a secondary side coil with a center tap, two ends of the primary side coil are respectively connected with the series nodes of the first and second switch sets, and the center tap is connected to the ground through the change-over switch; therefore, the pulse width modulation controller controls the on/off of the first and second switch sets and the change-over switch, so that the primary side coil of the transformer can be in a series or parallel structure, and the turn ratio of the transformer is further changed.

Description

Global switching power supply and its serial-parallel DC power conversion circuit

technical field

The invention relates to a DC-to-DC power conversion circuit, in particular to a series-parallel DC power conversion circuit.

Background technique

There are different types of switching power supply according to the AC power used. At present, it can be divided into 90V~130V low-voltage AC power supply and 185V-265V high-voltage AC power supply. Currently Taiwan uses 220V or 110V AC power supply, so switching power supply products include switching power supply for single AC power supply, or global switching power supply; among them, global switching power supply more popular.

Please refer to FIG. 8 , which is a circuit diagram of an existing global AC power supply, including a full-wave rectifier 50 , a step-up power factor correction circuit 51 and a DC power conversion circuit 52 . The full-wave rectifier 50 rectifies the AC power supply (AC IN) into a DC sine wave, and then the power factor correction controller 511 of the power factor correction circuit 51 with a boost circuit structure adjusts its voltage through the first active switch (S1). and current phase to output DC power with better power factor, and boost the voltage of the DC sine wave to about 400 volts of high-voltage DC power (V _BULK ). Afterwards, the high voltage DC power supply (V _BULK ) is input to the DC power conversion circuit 52, and the pulse width modulation controller 521 of the DC power conversion circuit 52 changes according to the voltage of its DC voltage output terminal (Vo), The current of the primary side of the transformer 522 is adjusted by the second active switch (S2) to maintain a stable DC voltage output (Vo).

From the above circuit structure of the switching power supply, it can be seen that the full-wave rectifier 50 will rectify the 220V or 110V AC source into DC sine waves with different voltages, but once input to the step-up power factor correction circuit 51, Both will be boosted to 400V high-voltage DC power supply (V _BULK ), so that the DC power conversion circuit of the subsequent stage can step down and stabilize the 400V high-voltage DC power supply to 12V or 5V before outputting to the load; if step-down power factor correction is used The circuit will step down to 80V, and cooperate with the DC power conversion circuit of the transformer with different turns ratio, that is, the 80V medium and high voltage DC power can be stepped down and stabilized to 12V or 5V, and then output to the load.

In terms of overall power conversion efficiency, when 220V AC power is input to the switching power supply, the power factor correction controller 511 of the step-up power factor correction circuit 51 will output a pulse width modulation signal to the first active switch (S1), so that the energy storage capacitor (C1) outputs a 400V DC power supply to the DC power conversion circuit 52 of the subsequent stage. At this time, the calculation of the overall power conversion efficiency is about 96%; yet when the 110V AC power input, the power The power factor correction controller 511 of the factor correction circuit 51 will increase the pulse width of the pulse width modulation signal, so that the energy storage capacitor (C1) also outputs 400V DC power, but due to the conduction time of the first active switch (S1) As the length becomes longer, the on-resistance of the first active switch ( S1 ) consumes more power, and reduces the overall conversion efficiency to 94%.

Taking the power factor correction controller of the step-down power factor correction circuit as an example, when 220V AC power is input to the above-mentioned switching power supply, the step-down power factor correction circuit must control the first active switch (S1) to adjust the voltage It can be seen that although the existing global switching power supply can use 220V or 110V AC power supply, it uses a step-up power factor correction circuit to plug in to 110V When using an AC power supply, or using a step-down power factor correction circuit to plug into a 220V AC power supply, the conversion efficiency of the overall circuit is not good, so a better circuit design must be sought.

Contents of the invention

The purpose of the present invention is to solve the technical problem of the power conversion efficiency of the existing Full Range switching power supply.

To achieve the above purpose, the present invention provides a global switching power supply, including:

a rectifier connected to an AC power source to convert the AC power source into a DC sine wave power source;

A signal detection unit, which detects the current input AC power voltage and outputs a detection signal;

A power factor correction circuit, the input end of which is connected to the output end of the rectifier and the output end of the signal detection unit, and adjusts the output voltage of the first DC power supply according to the current input AC power voltage; and

A series-parallel DC power conversion circuit, the input end of which is connected to the output end of the power factor correction circuit and the signal detection unit, so as to receive the first DC power supply and convert it into a second DC power supply for output; wherein the The series-parallel DC power conversion circuit adjusts the turns ratio of the primary side coil and the secondary side coil of the transformer according to the voltage ratio of the first DC power supply and the second DC power supply, so that the turns ratio of the transformer is the same as that of the first DC power supply and the second DC power supply. proportional to the DC supply voltage ratio.

To achieve the above purpose, the present invention also provides a series-parallel DC power conversion circuit, including:

A transformer including a center-tapped primary coil and a secondary coil;

A full-bridge switch circuit for connecting to the output terminal of the power factor correction circuit, and includes two parallel first and second switch groups, and each active switch group includes two series-connected upper arm active switches and lower arm active switches , and the series nodes of the first and second switch groups are connected to the two terminals of the primary side coil of the transformer;

a changeover switch connected between the center tap of the primary coil of the transformer and the ground terminal; and

A pulse width modulation controller, connected to the control terminals of the two upper arm active switches and the two lower arm active switches and the switching switch of the first and second switch groups; the pulse width modulation controller is based on a pre-stage power factor correction circuit According to the size of the output voltage, a turn adjustment procedure is carried out, that is, by controlling the active switch and the on-off state of the switch of the full-bridge switching circuit, the turn ratio of the transformer matching the output voltage is adjusted, and then the DC conversion procedure is performed.

The above-mentioned series-parallel DC power conversion circuit of the present invention is connected to the output terminal of the pre-stage power factor correction circuit, and the pulse width modulation controller can control the The active switch of the full-bridge switching circuit and the on-off state of the toggle switch, after adjusting the matching turns ratio of the output voltage, then select the appropriate active switch to perform the DC power conversion procedure; that is, the step-up power factor correction circuit For example, when using 220V high-voltage section AC power supply voltage to output about 400V high-voltage DC power supply to the full-bridge switching circuit, that is, the ratio of the number of turns of the primary side coil and the secondary side coil of the control transformer to the voltage ratio of the high-voltage DC power supply and the low-voltage DC power supply On the contrary, when using 110V low-voltage AC power supply voltage and outputting about 200V high-voltage DC power supply to the full-bridge switching circuit, the turns ratio of the transformer must be lowered so that the transformer turns ratio is the same as that of the high-voltage DC power supply and the low-voltage DC power supply. The voltage ratio is proportional; in this way, the DC-to-DC power conversion circuit of the present invention can output a stable and fixed low-voltage DC power voltage no matter what kind of AC power is used in conjunction with it.

The beneficial effect of the present invention is to provide a new global switching power supply and its serial-parallel DC power conversion circuit, wherein the serial-parallel DC power conversion circuit can output different voltages according to the previous power factor correction circuit For the DC power supply, the turns ratio of the transformer is changed to improve the power conversion efficiency of the global switching power supply of the present invention. Therefore, the DC-to-DC power conversion circuit of the present invention can be compatible with previous power factor correction circuits that output DC power with different voltages, so that the global switching power supply has better power conversion efficiency.

Description of drawings

FIG. 1 is a circuit block diagram of the global switching power supply of the present invention.

Fig. 2 is a detailed circuit diagram of the signal detection unit used in the first preferred embodiment of the present invention.

FIG. 3 is a detailed circuit diagram of the first preferred embodiment of the global switching power supply of the present invention.

FIG. 4A is a circuit action diagram of FIG. 3 for the AC power supply in the high-voltage section.

FIG. 4B is a circuit action diagram of FIG. 3 for the AC power supply in the low-voltage section.

FIG. 5 is a detailed circuit diagram of the second preferred embodiment of the global switching power supply of the present invention.

FIG. 6 is a detailed circuit diagram of the signal detection unit used in the second preferred embodiment of the present invention.

FIG. 7A is a circuit action diagram of FIG. 5 for the AC power supply in the high-voltage section.

FIG. 7B is a circuit action diagram of FIG. 5 for the AC power supply in the low-voltage section.

FIG. 8 is a detailed circuit diagram of an existing global switching power supply.

Explanation of reference signs:

10-DC power conversion circuit; 11, 11'-transformer; 111,111'-primary side coil; 111a, 111a'-coil; 111b, 11b'-coil; 112,112'-secondary side coil; 12-full Bridge switch circuit; 121-first switch group; 20, 20a-power factor correction circuit; 30-rectifier; 40-signal detection unit; 41-comparator; 50-full wave rectifier; 51-power factor correction circuit; 511 -Power factor correction controller; 52-DC power conversion circuit; 521-Pulse width modulation controller; 522-Transformer.

Detailed ways

First, please refer to Figure 1 and Figure 3, which is a global switching power supply of the present invention, which includes:

a rectifier 30, which can be commonly connected to an AC power source, to convert the AC power source into a DC sine wave power source;

A signal detection unit 40, which detects the magnitude of the current input AC power supply voltage and outputs a detection signal;

A power factor correction circuit 20, whose input terminal is connected to the output terminal of the rectifier 30 and the output terminal of the signal detection unit 40, adjusts the voltage of the first DC power supply (V _BULK ) output according to the current input AC power supply voltage ; In this embodiment, a step-up power factor correction circuit is used; and

A series-parallel DC power conversion circuit 10, its input end is connected to the output end of the power factor correction circuit 20 and the signal detection unit 40, to receive the first DC power supply (V _BULK ), and convert it to the second output after the DC power supply (V _out ); wherein the series-parallel DC power conversion circuit 10 adjusts the primary side coil 111 and the secondary side coil 111 of the transformer 11 according to the voltage ratio of the first DC power supply (V _BULK ) and the second DC power supply (V _out ). The turns ratio of the secondary coil 112 is such that the turns ratio of the transformer 11 is proportional to the voltage ratio of the first DC power supply (V _BULK ) and the second DC power supply (V _out ).

Please refer to FIG. 2, which is a detailed circuit diagram of a preferred embodiment of the above-mentioned signal detection unit 40, which includes:

a low-pass filter (R1, R2, C2), connected to the output terminal of the rectifier 10, to further filter the DC sine wave into a DC level;

A comparator 41, one input end of which is connected to the low-pass filter (R1, R2, C2), and the other input end is connected to a first reference voltage (V _ref1 ), and outputs high and low potential DC signals after comparison;

An electronic switch (Q), the control terminal of which is connected to the output terminal of the comparator 41, and the electronic switch (Q) is connected in series with a resistor (R13); and

A voltage divider is composed of two resistors (R11, R12) connected in series, wherein the lower resistor (R12) is connected in parallel with the electronic switch (Q) and resistor (R13) connected in series, and the series node of the voltage divider is connected to the corresponding power factor correction circuit 20 .

Please also refer to FIG. 3, which is a detailed circuit diagram of a switching power supply using a step-up power factor correction circuit 20, which includes:

An energy storage inductor (L), one end of which is connected to the output end of the full-wave rectifier 20;

An energy storage capacitor (C _bulk ), connected between the other end of the energy storage inductor (L) and the ground end, outputs a first DC power supply (V _BULK ) to the series-parallel DC power conversion circuit 10;

an electronic switch (Q5) connected between the nodes of the energy storage inductor (L) and energy storage capacitor (C _bulk ) and ground; and

A controller (M1), whose output terminal is connected to the control terminal of the electronic switch (Q5) and the output terminal of the corresponding signal detection unit 40, adjusts the control terminal output of the electronic switch (Q5) according to the signal detection unit 40. Pulse width modulation signal, the controller (M1) at least includes an error amplifier (M11), a second reference voltage terminal (V _ref2 ) and a switch drive unit (M12), wherein the error amplifier (M11) has an input terminal It is connected to the reference voltage terminal (V _ref2 ), and the other input terminal is connected to the series connection of the voltage divider ( R11 , R12 ) corresponding to the signal detection unit 40 .

The following will further illustrate the circuit action of the above-mentioned step-up power factor correction circuit 20:

When the 220V high-voltage AC power supply is currently connected, the comparator 41 of the signal detection unit 40 will output a high potential to drive the electronic switch (Q) to be turned on, so that the resistor (R13) and the lower resistor (R12) of the voltage divider ) in parallel, so the voltage level connected to the error amplifier (M11) in the controller (M1) and the voltage divider (R11, R12) will drop, thereby changing the output of the switch drive unit (M12) to the electronic switch ( The pulse width modulation signal of Q) makes each energy storage capacitor (C _bulk ) output a first DC power supply (V _BULK ) of about 400V.

When the 110V low-voltage segment AC power supply is connected at present, the comparator 41 of the signal detection unit 40 will output a low potential, so that the electronic switch (Q) is no longer conducting, so the resistor (R13) is no longer connected with the voltage divider (R11, R12) are connected in parallel with the lower resistance (R12); at this time, the voltage level connected between the error amplifier (M11) in the above-mentioned controller (M1) and the voltage divider (R11, R12) will rise, thereby changing the The switch driving unit (M12) outputs the pulse width modulation signal to the electronic switch (Q), and outputs about 200V first DC power (V _BULK ) on each energy storage capacitor (C _bulk ).

Therefore, the power factor correction circuit 20 of the switching power supply of the present invention does output the first DC power (V _BULK ) of different voltages to the subsequent series-parallel DC power conversion circuit according to the different AC power voltages used. 10.

As for the serial-parallel DC power conversion circuit 10 of the present invention, it further includes:

A transformer 11 includes a center-tapped primary side coil 111 and a secondary side coil 112. The primary side coil 111 includes two coils 111a, 111b; wherein the secondary side coil 112 is passed through a rectification filter circuit (D1-D4 , C _out ) to output a second DC power supply (V _out );

A full-bridge switch circuit 12 includes two parallel first and second switch groups 121, 122, and each first and second active switch group 121, 122 includes an upper arm active switch (Q1) (Q1) ( Q3) and lower arm active switches (Q2) (Q4), and the series nodes of the first and second switch groups 121, 122 are connected to the two terminals of the primary side coil 111 of the transformer 11; wherein each active switch (Q1～Q4) can be Be MOSFET or IGBT, adopt MOSFET in this embodiment, the gate of each MOSFET is its control terminal;

A switch (SW), connected between the intermediate tap of the primary side coil 111 of the transformer 11 and the ground terminal; in this embodiment, the switch (SW) is a relay; and

A pulse width modulation controller 13, connected to two upper arm active switches (Q1) (Q3) and two lower arm active switches (Q2) (Q4) and switching switches (SW) of the first and second switch groups 121, 122 The control terminal of the pulse width modulation controller 13 is connected to the series connection of the voltage divider (R11, R12) in the signal detection unit 40, or connected to the low pass in the signal detection unit 40. filter (R1, R2, C2); wherein the pulse width modulation controller 13 judges the output voltage of the pre-stage power factor correction circuit 20 according to the detection signal output by the signal detection unit 40, and performs a turn adjustment The procedure is to adjust the primary side coil of the transformer 11 to match the voltage of the first DC power supply (V _out ) by controlling the on-off state of the active switches (Q1-Q4) and the switching switch (SW) of the full-bridge switch circuit 12 111 and the turns ratio of the secondary side coil 112, and then carry out the DC conversion procedure, that is, select the appropriate active switch (Q1~Q4) to output the pulse width modulation signal, and convert the input first DC power supply (V _BULK ) through The transformer 11 with a proper turn ratio transforms the second DC power supply (V _out ) with a stable and fixed voltage.

The following will further explain how the above-mentioned pulse width modulation controller 13 adjusts the turns ratio of the primary side coil 111 and the secondary side coil 112 of the transformer 11 of the DC-DC power conversion circuit 13 according to the output voltage of the previous stage power factor correction circuit 20. Equivalent circuit diagram.

First, please refer to FIG. 4A , the pre-stage power factor correction circuit 20 is a boost circuit, and when using a high-voltage AC power supply, it will output a first high-voltage DC power supply (V _BULK ) from the output capacitor (C _bulk ). . In the case of using a 220V AC power supply, the step-up power factor correction circuit 20 outputs a first high-voltage DC power supply (V _BULK ) of about 400V, so the pulse width modulation controller 13 of the present invention must control the primary side coil 111 of the transformer 11 Maintain the maximum number of turns (Na), that is, control the upper arm active switch (Q3) of the second switch group 122 to be in the off state, and the lower arm active switch (Q4) to be in the on state, and at the same time control the switching switch (SW) to be normal In the open-circuit state, the primary side coil 111 of the transformer 11 constitutes a single coil, and its two ends are respectively connected between the series node of the first switch group 121 and the ground terminal, so that the turns ratio of the primary side coil 111 and the secondary side coil 112 is (Na:Nb) matching The pre-stage step-up power factor correction circuit 20 outputs a first high-voltage DC power supply (V _BULK ) of about 400V. At this time, the pulse width modulation controller 13 outputs two sets of pulse width modulation signals (PWM1, PWM2) with a pulse width of 50% to the active switch control terminals (G1) (G2) of the upper and lower arms of the first switch group 121 ), to alternately open and close the active switches (Q1) (Q2) of the upper and lower arms of the first switch group 121. Since the two ends of the primary side coil 111 are further connected in series with inductors and capacitors (Cr1, Lr1) (Cr2, Lr2), therefore in the second When the upper arm or the lower arm active switch (Q1) (Q2) of a switch group 121 is turned on, the primary side coil 111 can form a resonant tank circuit ( Resonance Tank), so that the secondary coil 112 of the transformer 11 outputs a stable and fixed second DC power (V _out ).

Please refer to FIG. 4B , when the above-mentioned step-up power factor correction circuit (20) uses a low-voltage segment (such as 110V) AC power supply, its output capacitor (C _bulk ) outputs a first medium-voltage DC power supply (V _BULK ), at this time the pulse width modulation controller 13 of the present invention controls the switching switch (SW) to be in a normally closed short-circuit state, and then outputs two groups of anti-phase 50% pulse width modulation signals to the two upper arm active switches (Q1) (Q3), and the two lower arm active switches (Q2) (Q4), which means that the two upper arm active switches (Q1) (Q3) are a synchronous switch group, while the two lower arm active switches (Q2) (Q4) are another A synchronous switch group. In this way, the intermediate joint of the primary side coil 111 of the transformer is grounded and independently formed into two coils (111a) (111b) connected in parallel through two upper arm active switches (Q1) (Q3) or two lower arm active switches (Q2) (Q4). ), to reduce the turns ratio (Na/2:Nb) of the primary side coil 111 and the secondary side coil 112 of the transformer 11, since the two ends of the primary side coil 111 are further connected in series with inductors and capacitors (Cr1, Lr1) (Cr2, Lr2), so when the two upper arm active switches (Q1) (Q3) are turned on at the same time, the two parallel coils 111a, 111b will form a resonant tank circuit with the inductance and capacitance (Cr1, Lr1) (Cr2, Lr2). Similarly, when the two lower arm active switches When the switches (Q2) (Q4) are turned on at the same time, the two parallel coils 111a, 111b will form a resonant tank circuit with the inductance and capacitance (Cr1, Lr1) (Cr2, Lr2), so that the turns ratio of the transformer 11 is the same as that of the first medium voltage DC power supply ( V _BULK ) is proportional to the second DC power supply voltage (V _out ).

From the above description, it can be seen that when the PWM controller 13 is applied to the boost power factor correction circuit 20, the control logic of the program for adjusting the number of turns is shown in the following table:

Please refer to FIG. 5 and FIG. 6, the power supply of the present invention adopts another preferred embodiment of a step-down power factor correction circuit 20a, wherein the step-down power factor correction circuit 20a includes:

An electronic switch (Q5), one end of which is connected to the output end of the rectifier 30;

An energy storage inductor (L), one end of which is connected to the other end of the electronic switch (Q5);

A diode (D), the cathode of which is connected to the series node of the electronic switch (Q5) and the energy storage inductance (L), and the anode of which is connected to the ground terminal;

an energy storage capacitor (C _bulk ), connected between the other end of the energy storage inductor (L1) and the ground end, and outputs a first DC power supply (V _BULK ) to the series-parallel DC power conversion circuit 10;

A controller (M1'), whose output terminal is connected to the control terminal of the electronic switch (Q5) and the output terminal of the corresponding signal detection unit 40, and adjusts the output to the control terminal of the electronic switch (Q5) according to the signal detection unit 40 A pulse width modulation signal, and the controller (M1') at least includes an error amplifier (M11), a second reference voltage terminal (V _ref2 ) and a switch drive unit (M12), wherein the error amplifier (M11) One input terminal is connected to the reference voltage terminal (V _ref2 ), and the other input terminal is connected to the series connection of the voltage divider corresponding to the signal detection unit 40 .

The circuit action of the above step-down power factor correction circuit will be further described below:

When the 220V high-voltage AC power supply is currently connected, the comparator 41 of the signal detection unit 40 will output a high potential to drive the electronic switch (Q) to be turned on, so that the resistor (R13) and the lower resistor (R12) of the voltage divider ) in parallel, so the voltage level connected to the error amplifier (M11) in the controller (M1') and the voltage divider (R11, R12) will drop, thereby changing the output of the switch drive unit (M12) to the electronic switch The pulse width modulation signal of (Q) makes each energy storage capacitor (C _bulk ) output a second high-voltage DC power supply (V _BULK ) of about 160V.

When the 110V low-voltage segment AC power supply is connected at present, the comparator 41 of the signal detection unit 40 will output a low potential, so that the electronic switch (Q) is no longer conducting, so the resistor (R13) is no longer connected with the voltage divider The lower resistor (R12) of (R11, R12) is connected in parallel; at this time, the voltage level connected to the error amplifier (M11) in the above-mentioned controller (M1') and the voltage divider (R11, R12) will rise, thereby changing The switch driving unit (M12) outputs the pulse width modulation signal to the electronic switch (Q), and outputs about 80V second medium voltage DC power (V _BULK ) on each energy storage capacitor (C _bulk ).

Therefore, the step-down power factor correction circuit 20a of the switching power supply of the present invention does output the first DC power of different voltages to the subsequent serial-parallel DC power conversion circuit according to the different voltages of the AC power used.

Please refer to FIG. 7A to further explain the circuit action of the series-parallel DC-to-DC power supply circuit 10 using a step-down pre-stage power factor correction circuit:

When the step-down power factor correction circuit 20a uses a 220V AC power supply, it will output a second high-voltage DC power supply (V _BULK ) of about 160V, so the pulse width modulation controller 13 of the present invention must control the primary side coil of the transformer 11'111' maintains the maximum number of turns (Nc), that is, controls the upper arm active switch (Q3) of the second switch group 122 to be in an off state, while the lower arm active switch (Q4) is in an on state, and simultaneously controls the switching switch (SW) It is in the normally open and disconnected state, so that the primary side coil 111' of the transformer 11' constitutes a single coil, and its two ends are respectively connected between the series node of the first switch group 121' and the ground terminal, so that the turns ratio (Nc:Nd) The matched pre-step-down power factor correction circuit 20 outputs a second high-voltage DC power supply (V _BULK ) of about 160V. At this time, the PWM controller 13 outputs two sets of pulse width modulation signals with a pulse width of 50% to the active switch control terminals (G1) (G2) of the upper and lower arms of the first switch group 121' to alternately Open and close the upper and lower arm active switches (Q1) (Q2) of the first switch group 121, since the two ends of the primary side coil 111' are further connected in series with the inductance and capacitance (Cr1, Lr1) (Cr2, Lr2), so in the first switch group When the upper arm or the lower arm active switch (Q1) (Q2) of 121 is turned on, the primary side coil 111 can form a resonance tank circuit (Resonance Tank) with two sets of inductance and capacitance (Cr1, Lr1) (Cr2, Lr2) connected in series , so that the secondary coil 121' of the transformer 11' outputs a stable and fixed second DC power (V _out ).

Please refer to Figure 7B. When the step-down power factor correction circuit uses a 110V low-voltage AC power supply, its output capacitor (C _BULK ) outputs a second medium-voltage DC power supply (V _BULK ) of about 80V. The inventive pulse width modulation controller 13 controls the switching switch (SW) to be in a normally closed short-circuit state, and then outputs two groups of anti-phase 50% pulse width modulation signals to the two upper arm active switches (Q1) (Q3), and the two The lower arm active switches (Q2) (Q4) mean that the two upper arm active switches (Q1) (Q3) are a synchronous switch group, and the two lower arm active switches (Q2) (Q4) are another synchronous switch group. In this way, the intermediate joint of the primary side coil 111' of the transformer 11' will be grounded and independently form two coils 111a' connected in parallel through two upper arm active switches (Q1) (Q3) or two lower arm active switches (Q2) (Q4) , 111b', to reduce the turns ratio (Nc/2:Nd) of the primary side coil 111' and the secondary side coil 112' of the transformer 11', that is, to reduce, because the two ends of the primary side coil are further connected in series with the inductance and capacitance (Cr1 , Lr1) (Cr2, Lr2), so when the two upper arm active switches (Q1) (Q3) are turned on at the same time, the two parallel coils will form a resonant tank circuit with the inductance and capacitance (Cr1, Lr1) (Cr2, Lr2). When the lower arm active switch (Q2) (Q4) is turned on at the same time, the two parallel coils 111a', 111b' will form a resonant tank circuit with the inductance and capacitance (Cr1, Lr1) (Cr2, Lr2), so that the primary side coil 111' of the transformer 11' The turns ratio of the secondary side coil 112' is proportional to the voltage ratio of the second medium voltage DC power supply (V _BULK ) and the second DC power supply (V _out ).

From the above description, it can be seen that when the PWM controller 13 is applied to the step-down power factor correction circuit 20a, the control logic of the program for adjusting the number of turns is shown in the following table:

It can be known from the above two embodiments that the present invention can adjust the transformer turns ratio matching the ratio of the DC power supply to the low-voltage DC power supply according to the size of the output DC power supply of the pre-stage power factor correction circuit, so that the present invention can be applied to global switching The switching power supply can cooperate with the use of different high-voltage or low-voltage AC power supplies, actively adjust the appropriate transformer turns ratio, and effectively improve the overall power conversion efficiency of the switching power supply.

The above description of the present invention is illustrative rather than restrictive. Those skilled in the art understand that many modifications, changes or equivalents can be made to it within the spirit and scope of the claims, but they will all fall into Within the protection scope of the present invention.

Claims (14)

1. a full range type switched power supplier is characterized in that, includes:

One rectifier is connected to an AC power, and this AC power is given exporting a rectifier power source after the rectification;

One signal detects the unit, detects present input ac power voltage swing, and exports one and detect signal;

One circuit of power factor correction, its input are connected to the output that this rectifier output end and signal detect the unit, according to input ac power voltage swing at present, adjust the voltage swing that it exports first DC power supply; And

Output and signal that one series-parallel direct-current power supply converting circuit, its input are connected to this circuit of power factor correction detect the unit, receiving first DC power supply, and export after being converted into second DC power supply; Wherein this series-parallel direct-current power supply converting circuit makes transformer turn ratio be directly proportional with first DC power supply and the second DC power supply voltage ratio according to the turn ratio of first DC power supply and the second DC power supply voltage ratio its transformer first siding ring of adjustment and second siding ring.

2. full range type switched power supplier as claimed in claim 1 is characterized in that, this signal detects unit pack and contains:

One low pass filter is connected to the output of this rectifier, this rectifier power source further is filtered into a direct current power supply;

One comparator, one input end is connected to low pass filter, and another input then connects one first reference voltage, after comparison, promptly exports high electronegative potential direct current signal;

One electronic switch, its control end is connected to the output of this comparator, and this electronic switch is connected in series a resistance again; And

One voltage divider is composed in series by two resistance, wherein descends the parallel connection of resistance and the electronic switch that is connected in series and resistance, and the series connection node under the last resistance of this voltage divider reaches again between the resistance is connected to corresponding circuit of power factor correction.

3. full range type switched power supplier as claimed in claim 2 is characterized in that this circuit of power factor correction is a booster circuit, and it includes:

One energy storage inductor, the one of which end is connected to the output of this rectifier;

One energy storage capacitor is connected between this energy storage inductor other end and the earth terminal, exports first DC power supply and gives this series-parallel direct-current power supply converting circuit;

One electronic switch is connected between the intermediate node and ground connection that this energy storage inductor is connected with energy storage capacitor; And

One controller; Its output is connected to the control end of this electronic switch and the output of corresponding voltage checking circuit; According to the adjustment of voltage checking circuit electronic switch controling end is exported a PWM signal; This controller includes an error amplifier, one second reference voltage end and a switch drive unit at least again, and wherein this error amplifier one input is connected to this second reference voltage end, and another input then is connected to the voltage divider series connection contact of corresponding voltage checking circuit.

4. full range type switched power supplier as claimed in claim 2 is characterized in that this circuit of power factor correction is a reduction voltage circuit, and it includes:

One electronic switch, the one of which end is connected with the output of this rectifier;

One energy storage inductor, the one of which end is connected to the other end of this electronic switch;

One diode, its negative electrode are connected to this electronic switch and energy storage inductor series connection node, and its anode then is connected to earth terminal;

One energy storage capacitor is connected between this energy storage inductor other end and the earth terminal, exports first DC power supply and gives this series-parallel direct-current power supply converting circuit;

One controller; Its output is connected to the control end of this electronic switch and the output of corresponding voltage checking circuit; According to the adjustment of voltage checking circuit electronic switch controling end is exported a PWM signal; This controller includes an error amplifier, one second reference voltage end and a switch drive unit at least again, and wherein this error amplifier one input is connected to this second reference voltage end, and another input then is connected to the voltage divider series connection contact of corresponding voltage checking circuit.

5. like claim 3 or 4 described full range type switched power suppliers, it is characterized in that this series-parallel direct-current power supply converting circuit includes:

One transformer includes a tapped first siding ring and a second siding ring;

One full bridge switching circuit; First and second switches set that includes two parallel connections; Each active switches set includes the upper arm active switch and the underarm active switch of two-phase serial connection, and the series connection node of this first and second switches set is connected with transformer first siding ring two ends again;

One switches switch, is connected between this transformer first siding ring centre tap and the earth terminal; And

One PWM controller; Be connected to the two upper arm active switch of first and second switches set and the control end of two underarms active switch and diverter switch; An input of this PWM controller is connected to the series connection contact that this signal detects voltage divider in the unit again; According to the output voltage size of this circuit of power factor correction, carry out number of turn adjustment program, promptly by the active switch of control full bridge switching circuit and the keying state of diverter switch; The transformer turn ratio of this output voltage of adjustment coupling is carried out the direct current conversion program afterwards again.

6. like claim 3 or 4 described full range type switched power suppliers, it is characterized in that this series-parallel direct-current power supply converting circuit includes:

One transformer includes a tapped first siding ring and a second siding ring;

One full bridge switching circuit; First and second switches set that includes two parallel connections; Each active switches set includes the upper arm active switch and the underarm active switch of two-phase serial connection, and the series connection node of this first and second switches set is connected with transformer first siding ring two ends again;

One switches switch, is connected between this transformer first siding ring centre tap and the earth terminal; And

One PWM controller; Be connected to the two upper arm active switch of first and second switches set and the control end of two underarms active switch and diverter switch; An input of this PWM controller is connected to this signal and detects and be connected to this signal in the unit and detect low pass filter in the unit again; According to the output voltage size of this circuit of power factor correction, carry out number of turn adjustment program, promptly by the active switch of control full bridge switching circuit and the keying state of diverter switch; The transformer turn ratio of this output voltage of adjustment coupling is carried out the direct current conversion program afterwards again.

7. full range type switched power supplier as claimed in claim 5 is characterized in that, the number of turn adjustment program package of this PWM controller contains:

When judging use high pressure section AC power; The upper arm of control second switch group initiatively switch is closed condition; And underarm active switch is conducting state; And control this diverter switch simultaneously for often cut-offfing line state, and to export two groups of pulsewidth width be the last underarm switch control end initiatively that 50% PWM signal gives first switches set, alternately to open and close the last underarm active switch of first switches set;

When judging use low pressure stage AC power; Make the upper arm active switch and the underarm active switch of this first and second switches set be respectively two groups of synchro switch groups; And to control this diverter switch be normally closed short-circuit condition, exports two groups of pulsewidth width simultaneously and be 50% PWM signal to corresponding synchro switch group.

8. full range type switched power supplier as claimed in claim 6 is characterized in that, the number of turn adjustment program package of this PWM controller contains:

When judging use high pressure section AC power; The upper arm of control second switch group initiatively switch is closed condition; And underarm active switch is conducting state; And control this diverter switch simultaneously for often cut-offfing line state, and to export two groups of pulsewidth width be the last underarm switch control end initiatively that 50% PWM signal gives first switches set, alternately to open and close the last underarm active switch of first switches set;

When judging use low pressure stage AC power; Make the upper arm active switch and the underarm active switch of this first and second switches set be respectively two groups of synchro switch groups; And to control this diverter switch be normally closed short-circuit condition, exports two groups of pulsewidth width simultaneously and be 50% PWM signal to corresponding synchro switch group.

9. full range type switched power supplier as claimed in claim 7 is characterized in that, this diverter switch is a relay.

10. full range type switched power supplier as claimed in claim 7 is characterized in that, each active switch can be MOSFET or IGBT.

11. full range type switched power supplier as claimed in claim 8 is characterized in that, this diverter switch is a relay.

12. full range type switched power supplier as claimed in claim 8 is characterized in that, each active switch can be MOSFET or IGBT.

13. a series-parallel direct-current power supply converting circuit is characterized in that, includes:

One transformer includes a tapped first siding ring and a second siding ring;

One full bridge switching circuit; First and second switches set that includes two parallel connections; Each active switches set includes the upper arm active switch and the underarm active switch of two-phase serial connection, and the series connection node of this first and second switches set is connected with transformer first siding ring two ends again;

One switches switch, is connected between this transformer first siding ring centre tap and the earth terminal;

One PWM controller is connected to the two upper arm active switch of first and second switches set and the control end of two underarms active switch and diverter switch; This PWM controller is according to the output voltage size of a prime circuit of power factor correction; Carry out number of turn adjustment program; Promptly by the active switch of control full bridge switching circuit and the keying state of diverter switch; The transformer turn ratio of this output voltage of adjustment coupling is carried out the direct current conversion program afterwards again.

14. series-parallel direct-current power supply converting circuit as claimed in claim 13 is characterized in that, the number of turn adjustment program package of this PWM controller contains:

When judging use high pressure section AC power; The upper arm of control second switch group initiatively switch is closed condition; And underarm active switch is conducting state; And control this diverter switch simultaneously for often cut-offfing line state, and to export two groups of pulsewidth width be the last underarm switch control end initiatively that 50% PWM signal gives first switches set, alternately to open and close the last underarm active switch of first switches set;

When judging use low pressure stage AC power; Make the upper arm active switch and the underarm active switch of this first and second switches set be respectively two groups of synchro switch groups; And to control this diverter switch be normally closed short-circuit condition, exports two groups of pulsewidth width simultaneously and be 50% PWM signal to corresponding synchro switch group.

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