TWI779914B - Power Converter with Voltage Output Modulation - Google Patents

Abstract

The present invention is a power converter with voltage output modulation, comprising an isolated DC/DC transformer, a primary side circuit and a secondary side circuit; the primary side circuit is connected to the primary side of the isolated DC/DC transformer The coil is used to transmit the DC input power to the primary side coil; the secondary side line is connected to the secondary side coil of the isolated DC/DC transformer, wherein the secondary side line includes a first output circuit and a In the second output circuit, a mode switching switch is connected in series in the first output circuit; when the power consumption of the load is relatively small, the mode switching switch is controlled to be non-conductive to interrupt the first output circuit, so that the secondary side circuit Output a relatively low first output voltage; when the power consumption of the load is relatively large, the mode switching switch is controlled to be turned on, so that the secondary side circuit outputs a relatively high second output voltage, by means of the present invention The power converter can realize the purpose of wide voltage adjustment range without greatly increasing the line.

Description

Power Converter with Voltage Output Modulation

The invention is a power converter, especially a power converter that can provide a wide range of voltage adjustment.

Electronic products are generally used with individually designed chargers, and the output power of the charger can meet the needs of the electronic products; however, different electronic products must prepare chargers with various output powers, which is extremely inconvenient for users .

In order to provide a wide range of voltage adjustment, the existing single charger usually integrates multiple sets of switching architectures to achieve high power and multiple voltage output functions. Please refer to Figure 11, the existing charger will include multiple sets of parallel isolated DC DC/DC conversion modules 300, 400, wherein one DC/DC conversion module 400 is responsible for low voltage requirements, and the other DC/DC conversion module 300 is responsible for high voltage requirements.

When the charger receives AC power through the input port 100, the AC power is converted into DC power by the rectifier unit 200, and then input to the primary side units of the DC/DC conversion modules 300, 400, and then the DC/DC The secondary side units of the conversion modules 300 and 400 output the converted DC power to the high power output port 500 and the normal power output port 600 respectively. Among them, the high power output port 500 outputs relatively high charging power, which can be applied to electronic products with high charging power requirements, while the general power output port 600 outputs relatively low charging power, which can be applied to low charging power requirements of electronic products.

However, the architecture shown in FIG. 11 requires multiple sets of isolated DC/DC converter modules 300 , 400 , which limits the space efficiency of the charger and increases the size of the charger, making it inconvenient to carry.

On the other hand, if the charger does not use multiple sets of isolated DC/DC converter modules, the same type of products currently on the market do not have a voltage output with a wide voltage adjustment range. For example, the USB developer forum ( The wide voltage adjustment specification released by the USB IF should have an output voltage of 5~48 volts (V) and a maximum output power of 240 watts (W), but the traditional architecture can only reach 5~20 volts and cannot meet the demand.

In view of the above problems, the present invention provides a "power converter with voltage output modulation", which can provide a wide voltage output that can meet the load conditions without the need to connect multiple sets of DC/DC converter modules in parallel.

To achieve the above purpose, the power converter with voltage output modulation includes:

An isolated DC/DC transformer having a primary side coil and a secondary side coil;

a primary side circuit, connected to the primary side coil of the isolated DC/DC transformer, for transmitting a DC input power to the primary side coil;

a secondary side line connected to the secondary side coil of the isolated DC/DC transformer, the secondary side line includes a first output loop and a second output loop;

A mode switching switch is connected in series with the first output circuit;

Wherein, when the mode switching switch is not turned on, the first output circuit is disconnected, and the secondary side circuit outputs a first output voltage; when the mode switching switch is turned on, the secondary side circuit outputs a second output voltage. output voltage, the second output voltage is higher than the first output voltage.

The mode switching switch is controlled to be on or off according to the power demand of the load, so as to adjust the configuration of the secondary side circuit and output a voltage that can meet the load demand. Among them, the present invention still only uses a single group The isolated DC/DC transformer does not need to use multiple sets of parallel converter modules for voltage conversion, so it can avoid the problems of multiple sets of converter modules occupying space and increasing weight, and at the same time can achieve the purpose of wide voltage adjustment range.

Please refer to the circuit shown in Figure 1, which is the detailed circuit of the first embodiment of the "power converter with voltage output modulation" of the present invention, including an isolated DC/DC transformer 10, a primary side circuit 20, a Secondary side line 30.

The DC/DC transformer 10 has a primary side coil 11 and a secondary side coil 12. In this implementation, the secondary side coil 12 is a center-tapped coil. The secondary side coil 12 has a first end 121, a The second end 122 and an intermediate tap end 123 .

The primary-side circuit 20 is connected to the primary-side coil 11 and includes: an inductor L, a resonant capacitor C, a first switch Q1 and a second switch Q2, wherein the first switch Q1 and the second switch Q2 are represented here as NMOS power transistor as an example. The inductance L is connected in parallel at both ends of the primary side coil 11; the resonant capacitor C is connected between an input terminal Vin and the same-named end of the primary side coil 11 (that is, the end with a marked point); the second switch Q2 It is connected in series between the non-identical end of the primary side coil 11 (that is, the end without a marked point) and ground; one end of the first switch Q1 is connected to the input terminal Vin, and the other end is connected to the non-identical end of the primary side coil 11. end.

The secondary side circuit 30 is connected to the secondary side coil 12, and includes a first output circuit and a second output circuit, and a mode switching switch Q _m is connected in series in the first output circuit; in this embodiment, the two The secondary circuit 30 has a first rectifier switch Q _sr1 and a second rectifier switch Q _sr2 , the first rectifier switch Q _sr1 is connected to the first terminal 121 of the secondary coil 12 and is connected to one of the mode switching switches Q _m One end is connected in series, and the other end of the mode switching switch Qm is grounded, whereby the secondary side coil 12, the first rectifier switch _Qsr1 and the mode _switching switch _Qm form the first output loop. The second rectifier switch Q _sr2 is connected in series between the second terminal 122 of the secondary side coil 12 and the ground terminal to form the second output loop; the middle tap terminal 123 of the secondary side coil 12 is connected to an output capacitor Co , the converted DC power can be output to the load through the two ends of the output capacitor Co. Both the first rectifier switch Q _sr1 and the mode switching switch Q _m are NMOS power transistors as examples, and the source terminals of the two are connected.

The power converter of the present invention can operate in a first working mode or a second working mode according to the electric power required by the load, wherein the power supply output by the power converter in the second working mode is greater than that in the first working mode output power supply. The first working mode is, for example, "asymmetric half-bridge flyback mode (asymmetric half-bridge flyback mode)", which can provide a first output voltage below 36 volts to the load; the second working mode is, for example, "half-bridge LLC control mode (half-bridge LLC mode) can provide a second output voltage of 36~48 volts to the load. The specific method is shown in Fig. 10, cooperate with a power supply controller 5 (PD controller) to detect the power consumption required by the load, when the power consumption required by the load is relatively small, the present invention operates in an asymmetrical half-bridge flyback On the contrary, when the power required by the load is relatively large, the present invention operates in the half-bridge LLC control mode. These two modes are described further below.

1. The first working mode (asymmetrical half-bridge flyback control mode):

Please refer to Figure 2. First, the meaning of each waveform is explained as follows:

Vds2: the voltage between the drain and the source of the second switch Q2.

Vgs2: the voltage between the gate and the source of the second switch Q2.

Ids2: current through the second switch Q2.

Icr: the current through the resonant capacitor C.

Isr2: current through the second rectifier switch Q _sr2 .

Vgsr2: the voltage between the gate and the source of the second rectifier switch Q _sr2 .

Vgs-mode: the voltage between the gate and the source of the mode switching switch Q _m .

In the asymmetric half-bridge flyback control mode, the mode switching switch Q _m is fixed and maintained non-conductive (OFF), so the Vgs-mode in Figure 2 is continuously at a low voltage level, because the mode switching switch Q _m is equivalent to Open circuit, so the first rectifier switch Q _{sr1 has} no effect. Further referring to FIG. 3A, FIG. 3A shows the circuit action when the first switch Q1 is not conducting, the second switch Q2 is conducting, and the second rectifying switch _Qsr2 is not conducting in the primary side circuit 20. It can be seen that the current Icr and Ids2 gradually rise , while the current Isr2 in the secondary side line 30 is approximately zero. 3B shows the circuit operation when the first switch Q1 is on, the second switch Q2 is off, and the second rectifier switch _Qsr2 is on. It can be seen that the secondary circuit 30 provides a half-wave current Isr2 _.

2. The second working mode (half-bridge LLC control mode):

Please refer to Figure 4, the meaning of each waveform is explained as follows:

Vds2: the voltage between the drain and the source of the second switch Q2.

Vgs2: the voltage between the gate and the source of the second switch Q2.

Icr: the current through the resonant capacitor C.

Isr1: current through the first rectifier switch Q _sr1 .

Isr2: current through the second rectifier switch Q _sr2 .

Vgsr1: the voltage between the gate and the source of the first rectifier switch _Qsr1 .

Vgsr2: the voltage between the gate and the source of the second rectifier switch Q _sr2 .

Vgs-mode: the voltage between the gate and the source of the mode switching switch Q _m .

In the half-bridge LLC control mode, the mode switching switch Q _m is always turned on (ON), so the Vgs-mode shown in FIG. 4 is always at a high voltage level. Further referring to FIG. 5A, FIG. 5A shows the circuit action when the first switch Q1 in the primary side line 20 is not conducting, the second switch Q2 is conducting, the first rectifying switch _Qsr1 is conducting, and the second rectifying switch _Qsr2 is not conducting. A current Isr1 in the secondary circuit 30 passes through the first rectifying switch Q _sr1 . 5B shows the circuit action when the first switch Q1 is turned on, the second switch Q2 is not turned on, the first rectifier switch _Qsr1 is not turned on, and the second rectifier switch _Qsr2 is turned on. There is a current Isr2 in the secondary side circuit 30 through the second Two rectifier switch Q _{sr2 .} According to the waveform in FIG. 4, it can be understood that in different periods, the secondary side circuit 30 can output current Isr1 and Isr2. Therefore, compared with the first operation mode, the power converter can provide relatively higher power supply in the second operation mode. power.

Please refer to FIG. 6 , the difference between the second embodiment of the present invention and the first embodiment lies in the connection method of the primary side circuit 20 . The primary side circuit 20 is still connected to the primary side coil 11 and includes: an inductor L, a resonant capacitor C, a first switch Q1 and a second switch Q2. The inductance L is connected in parallel with both ends of the primary side coil 11; the resonant capacitor C is connected between the ground and the non-identical end of the primary side coil 11; the first switch Q1 is connected between the same name end of the primary side coil 11 and ground Between; one end of the second switch Q2 is connected to the input terminal Vin, and the other end is connected to the same-named end of the primary side coil 11 .

Please refer to FIG. 7, the difference between the third embodiment of the present invention and the first embodiment is that the secondary side coil 12 of the DC/DC transformer 10 is a single coil, with only a first end 121 and a second end 122, without an intermediate tap end. And the structure of the secondary side circuit 30 is a full bridge rectifier circuit, the full bridge rectifier circuit includes a plurality of diodes D1~D4, wherein the two input terminals 31, 32 of the full bridge rectifier circuit are respectively connected to the secondary side coil The first terminal 12 and the second terminal of 12, and the two output terminals 33 and 34 of the full-bridge rectifier circuit are respectively connected to the two terminals of the output capacitor Co. The secondary side coil 12, the diode D1, the output capacitor Co, and the diode D4 are connected to form a first output loop, and the mode switch Q _m is connected in series with the diode D4; the secondary side coil 12, the diode The body D2, the output capacitor Co, and the diode D3 are connected to form a second output loop. When the mode switching switch _Qm is kept on, the full-bridge rectifier circuit provides full-wave rectification, so that the power converter operates in the second working mode; on the contrary, when the mode switching switch _Qm is kept off, its first working mode An output circuit is in an open state, and the full-bridge rectifier circuit only provides half-wave rectification, so that the power converter operates in the first working mode.

Fig. 8 is the fourth embodiment of the present invention. Compared with Fig. 7, one or several diodes in the full-bridge rectifier circuit are replaced by power transistors. In Fig. 8, the original diode D3 is changed to a A power transistor, the power transistor is connected in series with the mode switching switch Q _m .

Fig. 9 is the fifth embodiment of the present invention. Compared with Fig. 7, the original diodes D1~D4 in the full-bridge rectifier circuit are changed to power transistors, wherein the mode switching switch Q _m can be connected with any power transistors in series.

Please refer to FIG. 10 , the "power converter 1 with voltage output modulation" of the present invention is applied to a power supply, which can be a power adapter for charging an electronic device. The power supply also includes an anti-electromagnetic interference (EMI) unit 2, a rectification unit 3, a power factor correction unit 4, etc., wherein the AC input power (AC) passes through the anti-electromagnetic interference unit 2, the rectification unit 3 and the After processing by the power factor correction unit 4, it is input to the power converter 1 of the present invention. When the power supply controller 5 judges that the load needs higher charging power, the power supply controller 5 outputs complex control signals to the power converter 1 By controlling the on/off timing of the first switch Q1, the second switch Q2, the mode switch Qm, the first rectifier switch _Qsr1 , and the second rectifier switch _Qsr2 , _the power converter 1 operates in the half-bridge LLC control mode , to provide greater charging power to electronic devices. On the other hand, when the power supply controller 5 judges that the load needs lower charging power, the power supply controller 5 outputs complex control signals to the power converter 1, so that the power converter works in an asymmetrical half-bridge flyback control mode to provide lower charging power to electronic devices.

The present invention can control the state of the mode switching switch Qm to operate the power converter in different modes according to the power requirements required by different loads without the need to connect multiple groups of DC/DC conversion modules in parallel, and generate output power. The present invention realizes a wide voltage adjustment range (for example, 5~48V) with a relatively simple circuit structure, avoids the problems of bulky power converters and inconvenient portability, and is more beneficial as a power supply for portable devices.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this professional technology Personnel, without departing from the scope of the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or be modified into equivalent embodiments with equivalent changes, but any content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solution of the present invention.

1: Power converter

2: Anti-electromagnetic interference unit

3: rectifier unit

4: Power factor correction unit

5: Power supply controller

10: DC/DC Transformer

11: Primary side coil

12: Secondary side coil

121: first end

122: second end

123: Middle tap end

20: primary side line

30: Secondary side circuit

31,32: input terminal

33,34: output terminal

Q1: First switch

Q2: Second switch

Q _m : mode switching switch

Q _sr1 : the first rectifier switch

Q _sr2 : Second rectifier switch

C: Resonant capacitance

L: inductance

D1~D4: Diodes

100: input port

200: rectifier unit

300: DC/DC converter module

400: DC/DC converter module

500: High power output port

600: General power output port

Vin: input terminal

Co: output capacitance

Fig. 1: Circuit diagram of the first embodiment of the present invention. Fig. 2: Waveform diagram of the present invention operating in the first working mode. FIG. 3A is a circuit action diagram when the second switch Q2 is turned on when the present invention operates in the first working mode. FIG. 3B is a circuit action diagram when the second switch Q2 is not turned on when the present invention operates in the first working mode. Fig. 4: Waveform diagram of the present invention operating in the second working mode. FIG. 5A is a circuit action diagram when the second switch Q2 is turned on when the present invention operates in the second working mode. FIG. 5B is a circuit action diagram when the second switch Q2 is not turned on when the present invention operates in the second working mode. Fig. 6: Circuit diagram of the second embodiment of the present invention. Fig. 7: Circuit diagram of the third embodiment of the present invention. Fig. 8: Circuit diagram of a fourth embodiment of the present invention. Fig. 9: A circuit diagram of a fifth embodiment of the present invention. FIG. 10 is a circuit block diagram of the power converter of the present invention used in a power supply. Figure 11: Circuit block diagram of an existing charger.

1: Power converter

10: DC/DC Transformer

11: Primary side coil

12: Secondary side coil

121: first end

122: second end

123: Middle tap end

20: primary side line

30: Secondary side circuit

Q1: First switch

Q2: Second switch

Q _m : mode switching switch

Q _sr1 : the first rectifier switch

Q _sr2 : Second rectifier switch

C: Resonant capacitance

L: inductance

Vin: input terminal

Co: output capacitance

Claims (9)

A power converter with voltage output modulation, comprising: an isolated DC/DC transformer with a primary side coil and a secondary side coil; a primary side circuit connected to the isolated DC/DC transformer The primary side coil is used to transmit a DC input power to the one primary side coil; a secondary side circuit is connected to the secondary side coil of the isolated DC/DC transformer, and the secondary side circuit includes a first side coil An output circuit and a second output circuit; a mode switching switch is connected in series with the first output circuit; wherein, when the mode switching switch is not conducting, it operates in a first working mode, and the first output circuit For disconnection, the secondary side circuit outputs a first output voltage; when the mode switching switch is turned on, it operates in a second working mode, the secondary side circuit outputs a second output voltage, and the second output The voltage is higher than the first output voltage; wherein, the first working mode is an asymmetrical half-bridge flyback control mode, and the first output voltage is below 36 volts; the second working mode is a half-bridge LLC control mode, and the The second output voltage is a voltage between 36-48 volts. The power converter with voltage output modulation as described in Claim 1, wherein: the secondary side coil is a middle tapped coil, including a first end, a second end and a middle tap end; the secondary side circuit It includes a first rectifier switch and a second rectifier switch, wherein the first rectifier is connected to the first end of the secondary side coil and connected in series with the mode switching switch, and the other end of the mode switching switch is grounded to form the second an output loop; the second rectifier switch is connected between the second terminal of the secondary side coil and the ground terminal to form the second output loop; The middle tap end of the secondary coil is connected to an output capacitor. As for the power converter with voltage output modulation described in Claim 2, the first rectification switch and the mode switching switch are both NMOS power transistors, and their source terminals are connected to each other. The power converter with voltage output modulation as described in Claim 1, wherein, the secondary side coil has a first end and a second end; the secondary side circuit is a full-bridge rectifier circuit, and the full-bridge rectifier The circuit is formed by the first diode to the fourth diode, and has two input terminals and two output terminals, wherein the two input terminals are respectively connected to the first terminal and the second terminal of the secondary side coil, and the two output terminals An output capacitor is connected between them; the mode switching switch is connected in series with one of the first to fourth diodes. The power converter with voltage output modulation as described in Claim 1, wherein, the secondary side coil has a first end and a second end; the secondary side circuit is a full-bridge rectifier circuit, and the full-bridge rectifier The circuit is formed by a plurality of diodes and at least one power transistor, and has two input terminals and two output terminals, wherein the two input terminals are respectively connected to the first terminal and the second terminal of the secondary side coil, and the two output terminals An output capacitor is connected between them; the mode switching switch is connected in series with one of the plurality of diodes or the at least one power transistor. The power converter with voltage output modulation as described in Claim 1, wherein, the secondary side coil has a first end and a second end; the secondary side circuit is a full-bridge rectifier circuit, and the full-bridge rectifier The circuit is formed by a plurality of power transistors and has two input terminals and two output terminals, wherein the two input terminals are respectively connected to the first terminal and the second terminal of the secondary side coil, and an output capacitor is connected between the two output terminals; The mode switching switch is connected in series with one of the plurality of power transistors. The power converter with voltage output modulation as described in any one of claims 1 to 6, wherein the primary side circuit includes: an inductor connected in parallel to both ends of the primary side coil; a resonant capacitor connected to the constant Between the input terminal of the current power supply and the terminal with the same name of the primary side coil; a first switch, one end of which is connected to the input terminal of the power supply, and the other end is connected to the non-identical terminal of the primary side coil; a second switch is connected in series on the primary side Between the non-identical end of the coil and the ground. A power converter with voltage output modulation as described in any one of claims 1 to 6, wherein the primary side circuit includes: an inductor connected in parallel to both ends of the primary side coil; a resonant capacitor connected to a Between the ground terminal and the non-identical terminal of the primary side coil; a first switch, one end of which is connected to the ground terminal, and the other end is connected to the same terminal of the primary side coil; a second switch is connected in series to the non-identical terminal of the primary side coil. Between the terminal with the same name and a DC power input terminal. The power converter with voltage output modulation as described in Claim 1, wherein the mode switching switch is connected to a power supply controller, and the power supply controller outputs a control signal according to the power demand of the load to control the mode switching switch.

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