TWI620402B - DC-DC transformer device and method for guiding same - Google Patents

Abstract

The present invention describes an improved DC-DC transformer device for obtaining a constant output voltage. In an embodiment of the invention, the improved DC-DC voltage transforming device comprises: a DC voltage source, an output DC power supply voltage; a main circuit for converting an input voltage into an output voltage having a set value; an auxiliary circuit coupled And connecting to the DC voltage source for coupling to the main circuit when the input voltage fluctuates beyond a predetermined range, so that the output voltage is maintained at the output voltage having the set value. Other embodiments are also described herein.

Description

DC-DC transformer device and method for controlling same

This invention relates to DC-DC transformer devices, and more particularly to improved DC-DC transformer devices for obtaining a constant output voltage by an auxiliary circuit.

A DC/DC converter is a voltage converter that efficiently converts a DC input voltage into a constant DC output voltage. Examples of such transformers include bridge circuits, Bulk, Boost, and the like. That is, by using such a transformer circuit, a desired constant output voltage can be obtained via conversion from a large unsteady input direct current (DC) power source or an alternating current (AC) power source.

During operation, the input voltage value of the unsteady input DC power source tends to fluctuate up and down. If the fluctuation range is smaller, the efficiency of the above-mentioned transformer circuit is higher (that is, the lower the loss of the circuit). Therefore, in order to obtain a high-efficiency transformer circuit, the gain range often needs to be designed to be smaller.

However, if the input power supply has a large voltage fluctuation range, the high-efficiency transformer circuit cannot be directly applied because the current high-efficiency transformer circuit usually has a small gain range.

In order to realize a high-efficiency transformer circuit that can be directly applied to an input power source having a large voltage fluctuation range, an auxiliary transformer circuit is usually set between the transformer circuit and the power source. When the input voltage range of the transformer circuit exceeds a predetermined range, the auxiliary transformer circuit can narrow the wider input voltage range to accommodate the transformer circuit. For example, assume that the transformer input circuit has a predetermined input voltage range of 24V to 36V. If the input voltage is 12V to 48V, the predetermined input range is exceeded. In such cases, the width of the input voltage is usually reduced to 24V to 36V by the auxiliary transformer circuit. It is then applied to the input terminal of the above-mentioned transformer circuit.

For another example, the Chinese patent (CN200780051915.3) provides a DC/DC converter comprising: a pre-regulator stage that can include a buck converter; and a post-converter stage that can include a charge pump. The duty factor of the preregulator stage is controlled by a feedback path extending from an output terminal of the preregulator stage or the post converter stage. Depending on the duty cycle, the preregulator depresses the input DC voltage by a variable amount, and the post converter boosts the voltage at the output of the preregulator with a positive or negative integer or fractional value. Press or depressurize.

However, such designs can cause other problems. For example, regardless of whether the input voltage falls within a predetermined range or exceeds a predetermined range, the auxiliary transformer circuit coupled to the main circuit is always in operation due to the transformer circuit that is placed in the back, and thus consumes energy. That is, in the case where it is not necessary to use the auxiliary transformer circuit (for example, the input circuit falls within a predetermined range), the auxiliary transformer circuit set between the main circuit and the power source inevitably consumes energy.

It can be seen that this type of design does not improve the overall efficiency of the circuit, because the auxiliary voltage transformer circuit of the front also reduces the input voltage range, so the gain range is designed to be smaller and the voltage is changed. The benefits of the circuit (reduced loss) are therefore offset.

The first aspect of the present invention relates to a DC-DC transformer device comprising: a DC voltage source, an output DC power supply voltage; a main circuit for converting an input voltage into an output voltage having a set value; an auxiliary circuit coupled And connecting to the DC voltage source for coupling to the main circuit when the input voltage fluctuates beyond a predetermined range, so that the output voltage is maintained at the output voltage having the set value. When the input voltage exceeds the predetermined range, coupling the auxiliary circuit to the main circuit includes coupling the auxiliary circuit to an input of the main circuit. When the input voltage exceeds the predetermined range, coupling the auxiliary circuit to the main circuit includes coupling the auxiliary circuit to the main circuit Output. The nominal upper limit of the input voltage fluctuation is equal to the upper limit of the predetermined range. The value of the input voltage fluctuation range exceeding the predetermined range is smaller than the difference between the upper limit and the lower limit of the predetermined range.

The DC-DC transformer device also includes a first energy storage circuit and a second energy storage circuit, wherein two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, and the first energy storage circuit Two ends are coupled to the output of the DC voltage source, and wherein when the auxiliary circuit is coupled to the main circuit, the auxiliary circuit charges the second tank circuit and stores energy in the second tank circuit This will then be transmitted to the load via this main circuit.

The DC-DC transformer device also includes a first energy storage circuit and a second energy storage circuit. The two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, and the two first energy storage circuits are The terminal is coupled to the output of the main circuit, and wherein the second tank circuit provides an additional supplemental voltage to the load output when the auxiliary circuit is coupled to the main circuit. In the DC-DC converter device, the first energy storage circuit and the second energy storage circuit are capacitors.

The DC-DC transformer device further includes a controller that controls charging and discharging of the second tank circuit by the main circuit and the auxiliary circuit, and wherein the controller controls the auxiliary circuit to charge the second tank circuit When the main circuit does not discharge the second energy storage circuit, or the controller controls the auxiliary circuit to charge the second energy storage circuit, the main circuit does not charge the second energy storage circuit. The DC-DC transformer device further includes a switch in parallel with the second tank circuit, the switch being turned on when the input voltage does not exceed the predetermined range.

In the DC-DC transformer device, the lower limit of the predetermined range includes a first threshold and a second threshold, and when the input voltage is higher than the first threshold, the auxiliary circuit is coupled to The main circuit disconnects the auxiliary circuit from the main circuit when the input voltage is lower than the second threshold. The auxiliary circuit includes an auxiliary transformer and an auxiliary switch, wherein the transformer is connected in series with the auxiliary switch to two outputs of the DC voltage source. In the DC-DC transformer device, The main circuit includes a half bridge LLC circuit that includes a main transformer.

A second aspect of the present invention relates to a method for controlling a DC-DC voltage transforming device to output a constant voltage, the DC-DC voltage transforming device comprising a main circuit and an auxiliary circuit, the method comprising: detecting an input voltage; determining Detecting whether the input voltage falls within a predetermined range; if the detected input voltage falls within a predetermined range, the auxiliary circuit is coupled to the main circuit by a control switch.

The method includes coupling the auxiliary circuit to the main circuit including coupling the auxiliary circuit to an input of the main circuit. The method includes coupling the auxiliary circuit to the main circuit including coupling the auxiliary circuit to an output of the main circuit. The main circuit includes a half bridge LLC circuit. The auxiliary circuit includes an auxiliary transformer and a first auxiliary switch.

The method also includes the auxiliary circuit being coupled to the main circuit when the first auxiliary switch is turned on and off at a certain frequency, and the auxiliary circuit is not coupled to the first auxiliary switch when the first auxiliary switch is turned off The main circuit.

The DC-DC transformer device further includes a first energy storage circuit (C1) and a second energy storage circuit (C2), and two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, Both ends of the first tank circuit are connected to the output of the DC voltage source, and wherein when the auxiliary circuit is coupled to the main circuit, the auxiliary circuit charges the second tank circuit and stores the second tank The energy in the energy circuit will then be transmitted to the load via the main circuit.

The DC-DC transformer device also includes a first energy storage circuit (C1) and a second energy storage circuit (C2), and two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, the first Both ends of a tank circuit are coupled to the output of the main circuit, and wherein the second tank circuit provides an additional supplemental voltage to the load output when the auxiliary circuit is coupled to the main circuit.

The method also includes a switch in parallel with the second tank circuit, when the input voltage is not exceeded The switch is turned on when the predetermined range is reached. The method also includes using the controller to control charging or discharging of the second tank circuit by the main circuit and the auxiliary circuit, including using the controller to control the auxiliary circuit to charge the second tank circuit, the main circuit is incorrect The main circuit does not charge the second tank circuit when the second tank circuit is discharged or when the controller is used to control the auxiliary circuit to charge the second tank circuit.

1‧‧‧ nodes

2‧‧‧ nodes

3‧‧‧ nodes

4‧‧‧ nodes

5‧‧‧ nodes

6‧‧‧ nodes

7‧‧‧ nodes

8‧‧‧ nodes

9‧‧‧ nodes

10‧‧‧ nodes

11‧‧‧ nodes

12‧‧‧ nodes

111‧‧‧ switch

112‧‧‧Transformers

113‧‧‧ diode

114‧‧‧ Capacitance

121‧‧‧ Capacitance

122‧‧‧ Capacitance

130‧‧‧ Capacitance

131‧‧‧ switch

132‧‧‧ switch

133‧‧‧Inductance

134‧‧‧Transformer

135‧‧‧ secondary side

136‧‧‧ secondary side

137‧‧‧ diode

138‧‧ ‧ diode

139‧‧‧ capacitor

322‧‧‧ Capacitance

323‧‧‧Switch

411‧‧‧ switch

412‧‧‧ Capacitance

413‧‧‧Transformer

414‧‧‧ diode

421‧‧‧ Capacitance

422‧‧‧ Capacitance

423‧‧‧Load resistor

431‧‧‧Switch

432‧‧‧ switch

433‧‧‧ Capacitance

434‧‧‧Inductance

435‧‧‧ Capacitance

436‧‧‧Transformer

437‧‧‧ secondary side

438‧‧‧ secondary side

439‧‧‧ diode

622‧‧‧ switch

624‧‧‧Switch

C1‧‧‧ capacitor

C2‧‧‧ capacitor

I_part1‧‧‧ waveform

I_part3‧‧‧ waveform

Q ₁ ‧‧‧Switch

Q ₂ ‧‧‧Switch

Q ₃ ‧‧‧Switch

Q ₄ ‧‧‧Switch

R‧‧‧ load resistor

V _in ‧‧‧DC power supply

BRIEF DESCRIPTION OF THE DRAWINGS In order to provide a more complete understanding of the invention, the invention, Circuit diagram of the transformer device.

Fig. 2 is a view showing a current waveform diagram of the auxiliary circuit shown in Fig. 1 when the energy is output, and a waveform of the current when the energy storage circuit C1 in the second circuit portion performs energy output to the load terminal.

FIG. 3 illustrates a circuit diagram of a DC-DC transformer device in accordance with another embodiment of the present invention.

4 illustrates a circuit diagram of a DC-DC transformer device in accordance with yet another embodiment of the present invention.

Fig. 5 exemplifies a current waveform diagram when the auxiliary circuit performs energy output and a waveform diagram of a current when the main circuit performs energy output to the storage circuit C1.

FIG. 6 illustrates a circuit diagram of a DC-DC transformer device in accordance with another embodiment of the present invention.

The present invention will be further described in detail with reference to the accompanying drawings and drawings. FIG. Components having the same or similar reference numerals in the drawings may operate similarly. The specific structures shown in the drawings are only possible examples, and those skilled in the art can make modifications as needed within the scope of the invention without departing from the spirit and scope of the invention.

In order to avoid the energy loss caused by the auxiliary circuit of the preamplifier in reducing the input voltage range, the present invention introduces an improved auxiliary circuit, and the auxiliary transformer circuit is coupled to the controller by the controller when the input voltage exceeds a predetermined range. The main circuit is configured to convert the input voltage to within a predetermined range; and when the input circuit falls within a predetermined range, the auxiliary circuit is disconnected by the controller to avoid consuming energy.

In an embodiment of the invention, the output of the auxiliary circuit is coupled to the input of the main circuit. In this connection mode, when the output of the auxiliary circuit is coupled to the input of the main circuit, the main circuit is discharged. In another embodiment of the invention, the output of the auxiliary circuit is coupled to the output of the main circuit. In this mode, when the output of the auxiliary circuit is coupled to the output of the main circuit, an additional supplemental voltage is provided to the load at the output.

1 illustrates a circuit diagram of a series-mode DC-DC voltage transformer in accordance with an embodiment of the present invention. In FIG. 1, the DC-DC transformer device includes a DC power source, a first circuit portion, a second circuit portion, and a third circuit portion.

The first circuit portion includes a switch Q1 111, a transformer 112, a diode 113, and a capacitor 114. In this context, the first circuit is also referred to as an auxiliary circuit. Thus, throughout the specification, the terms "first circuit portion" and "auxiliary circuit" are used interchangeably. The second circuit portion includes a capacitor C1 121 and a capacitor C2 122. In the embodiments of the present invention, the term "capacitance" may also be referred to as "storage circuit" or "energy storage element." The third circuit portion includes a switch Q2 131, a switch Q3 132, a transformer 134, and an inductor 133. In this context, the third circuit portion is also referred to as the "main circuit." Therefore, throughout the specification, the terms "third circuit portion" are used interchangeably with "main circuit."

As shown in FIG. 1, the two output terminals of the DC power source Vin are coupled to the nodes 1 and 2. One input of the primary side of the transformer 112 is coupled to the node 2, and the other input is coupled to the node 3 via the switch Q1 111. One output of the secondary side of the transformer 112 is coupled to the node 4 via the diode 113. The other output is coupled to node 5. Capacitor 114 is coupled between nodes 1 and 2. The capacitor 114 is used to buffer the circuit system when the input voltage fluctuates greatly.

The two terminals of the capacitor C1 121 in the second circuit portion are respectively coupled to the nodes 6 and 7. The two terminals of the capacitor C2 122 in the second circuit portion are coupled to the nodes 4 and 5, respectively.

In addition, as shown in FIG. 1, switch Q2 131 is coupled between nodes 4 and 8, and switch Q3 132 is coupled between nodes 8 and 9. The node 8 is coupled via an inductor 133 to one of the primary sides of the transformer 134, and the node 9 is coupled via capacitor 130 to the other input of the primary side of the transformer 134.

The secondary side of the transformer 134 can include a plurality of secondary side portions. As shown in the embodiment of FIG. 1, the secondary side of transformer 134 can include, for example, two secondary side portions 135, 136. One output of the secondary side portion 135 is coupled to the node 10 via a diode 137. One output of the secondary side portion 136 is also coupled to the node 10 via a diode 138. The secondary side portions 135, 136 share an output terminal, and the shared output terminal is coupled to the node 12. Capacitor 139 and load resistor R are coupled between node 11 and node 12 to form a parallel connection.

In the third circuit portion, the inductance 133, the parasitic inductance of the primary side of the transformer 134, and the capacitor 130 constitute a half-bridge LLC circuit. By controlling the switches Q2 131, Q3 132, the half-bridge LLC circuit can realize the current waveform at the time of energy transfer as shown by I_part 3 in FIG.

The circuit system of the present invention (i.e., the DC-DC transformer device) may also include a controller (not shown) for controlling the switching of the switches Q1 111, Q2 131, Q3 132. In an embodiment of the invention, when the switch Q1 111 is turned off by the controller, the auxiliary circuit does not function in the entire circuit system. That is, the auxiliary circuit is not coupled to the input of the main circuit. When the switch Q1 111 is turned on and off at a certain frequency by the controller, a current is induced in the primary side loop of the transformer to transfer energy to the secondary side of the transformer. At this time, the auxiliary circuit is coupled to the main circuit to function in the entire circuit system.

The solution of the invention aims to achieve a constant voltage output. In the embodiment of Figure 1, the input range of the DC power source Vin can be, for example, 36V to 72V. Assuming that the constant output voltage of the DC-DC converter is expected to be 12V, the output gain is 1/3 to 1/6. However, considering that the transformer 134 has a variation ratio of 3, the gain change rate (i.e., the ratio of the maximum gain to the minimum gain) ranges from 2 to 1. Due to the characteristics of the LLC line, if the gain change rate range is set to 2 to 1, it is difficult to obtain a good effect in the full gain range because the gain change rate is relatively large.

The gain change rate of the half-bridge LLC line is now set to 1 to 1.5, that is, the predetermined input voltage range is 48V to 72V, and the output voltage is 12V. At this time, if the voltage system 36 is input, it means that the range of 48V to 72V is exceeded. In order to ensure normal operation even if the input voltage exceeds a predetermined input voltage range (i.e., 48 to 72 volts), in addition to capacitor C1 121, capacitor C2 122 is provided to provide additional energy.

Specifically, when the input voltage is 36V, the voltage across the capacitor C1 121 is 36V. At this time, the auxiliary circuit is coupled to the circuit system by the controller to control the switch Q1 111 to form a series connection with the main circuit. Since the auxiliary circuit is coupled in series to the main circuit, the capacitor C2 122 in the auxiliary circuit is thereby coupled into the circuit system.

By setting the voltage across capacitor C2 122 to 12V, the voltage on the input side of the main circuit becomes 48V (i.e., the voltage on capacitor C1 121 is 36V plus the voltage on capacitor C2 122 is 12V). That is, with an input voltage of 36V (which exceeds the predetermined input voltage range of 48V to 72V), by adding capacitor C2 122 to provide an additional 12V, the voltage on the input side of the main circuit becomes 48V (falling at the predetermined input voltage) In the range), the circuit system can still operate normally. That is, of the total output energy, 1/4 of the energy is transferred to the second circuit portion via the first circuit portion.

When the input voltage falls within the predetermined input voltage range, the switch Q1 is controlled by the controller. 111 is turned off to disconnect the auxiliary circuit from the circuitry, thereby causing the capacitor C2 122 to open in the autonomous circuit. Since capacitor C2 122 is not coupled into the circuitry (ie, the auxiliary circuitry is not operating), only capacitor C1 121 is delivering energy during operation. At this time, since the current input from the third circuit portion is pulsed, the pulse current flows into the third circuit portion via the capacitor C2 122.

When the input voltage exceeds the predetermined input voltage range, the controller turns off and turns on the switch Q1 111 at a certain frequency to couple the auxiliary circuit to the main circuit, thereby coupling the capacitor C2 122 into the circuit system.

It can be seen that by providing an auxiliary circuit, part of the input energy can be adjusted to adapt to a narrower predetermined input range, thereby improving the efficiency of the entire circuit system.

In addition, in the embodiment of the present invention, the rated upper limit of the fluctuation range of the input voltage may be set equal to the upper limit of the predetermined input voltage range.

Here, the rated upper limit, lower rated limit and rated range of the input voltage can be understood as: the input voltage fluctuates within this range, which enables the circuit device and function to be used normally. If the fluctuation is outside this range, some protection means are sometimes required. The means of protection are not within the scope of the present invention. That is, the fluctuation of the input voltage is free, and the voltage range that can be used normally or relatively normally used for the loaded circuit and its components can be set to the rated upper limit, the rated lower limit, and the rated range.

In addition, the rated lower limit of the fluctuation range of the input voltage may be set, and may be set such that the value of the fluctuation range exceeding the predetermined input voltage range is smaller than the difference between the upper limit and the lower limit of the predetermined input voltage range, because The probability of using the main circuit is higher than the probability of using the auxiliary circuit.

It should be understood that the above setting of the fluctuation range of the input voltage is merely exemplary, and the present invention is not limited thereto.

Additionally, in an embodiment of the invention, the determination of whether the input voltage falls within a predetermined input voltage range can be achieved by control logic. For example, the control logic can be a control component implemented using an electronic device such as a microcontroller. When the input voltage is judged, the input voltage can be detected, and then it is judged according to the threshold value whether the input voltage falls within the range of the voltage value calculated according to the gain range of the main circuit. If it falls within the range of voltage values, the auxiliary circuit is connected. If it does not fall within the range of voltage values, the auxiliary circuit is not connected.

In the embodiment of the present invention, the threshold for determining whether the input voltage falls within the range of the voltage value may be a range, and is not limited to a fixed value, so as to prevent the switching device from being frequently turned on and off. In an embodiment of the invention, the threshold may include a first threshold and a second threshold, and when the input voltage is higher than the first threshold, the auxiliary circuit is coupled to the main circuit, and When the input voltage is lower than the second threshold, the auxiliary circuit is disconnected from the main circuit. Although the lower limit of the predetermined voltage input range is defined herein as two threshold values, it should be understood that the number of the threshold values is not limited thereto, but may be any number.

In the circuit system shown in Fig. 1, when the auxiliary circuit inputs energy to the second circuit portion, no energy is required to be transferred from the second circuit portion to the main circuit. Because if there is energy in and out of the second circuit portion at the same time, there is no way to control the proportion of the energy flowing through the first circuit portion in the total energy.

2 illustrates a waveform diagram of a current flowing through the diode 113 when the auxiliary circuit shown in FIG. 1 charges the C2 122 and a current flowing through the switch Q2 131 when the energy is transmitted to the load via the main circuit. As shown in FIG. 2, I_part1 indicates that the auxiliary circuit charges the capacitor C2 122 in the second circuit portion, and I_part3 indicates that the capacitor C1 121 and the capacitor C2 122 in the second circuit portion are discharged together to the main circuit.

In order to better control the proportion of the energy flowing through the first circuit portion in the total energy, Preferably, the waveform I_part1 is shifted in phase with the waveform I_part3.

In combination with the control of the switches Q2 131 and Q3 132 in the half-bridge LLC circuit, by controlling the switch Q1 111 in the auxiliary circuit shown in Fig. 1, the waveform I_part1 and the waveform I_part3 in Fig. 2 can be shifted in phase.

Specifically, in the case where the auxiliary circuit is coupled to the main circuit, that is, when the switch Q1 111 is turned on and off alternately, the frequency of the switch Q1 111 can be controlled by the controller so that the current flow in the first circuit portion The capacitor C2 122 in the second circuit portion is charged while passing through the diode 113, and at this time the switch Q2 is turned off. At this time, the capacitor C1 121 in the second circuit portion does not transfer energy to the third circuit portion. When the auxiliary circuit no longer charges capacitor C2 122, that is, when charging is complete, switch Q2 is turned "on". At this point, capacitor C1 121, along with capacitor C2 122, transfers energy to the third circuit portion, thereby transferring energy to the load.

The frequency of the switch Q1 111 can also be controlled by the controller such that when the first circuit portion transfers energy to the capacitor C2 122 in the second circuit portion, the capacitor C1 121 in the second circuit portion does not output energy to the third circuit portion. .

When the output end of the auxiliary circuit is coupled to the input end of the main circuit, the input of both the main circuit and the auxiliary circuit is connected in parallel with the power supply voltage, so if the phase is not staggered, the current on the main circuit and the auxiliary circuit will be based on the two circuits. The ratio of the resistance values on the sides is assigned.

Thereby, the waveform I_part1 is shifted from the waveform I_part3, so that the magnitude of the current flowing through the first circuit portion can be easily controlled without being affected by the resistance ratio.

FIG. 3 illustrates a circuit diagram of a DC-DC transformer device in accordance with another embodiment of the present invention. The circuit configuration of the DC-DC transformer device illustrated in FIG. 3 is substantially similar to the circuit configuration of the DC-DC transformer device illustrated in FIG. However, the circuit configuration shown in FIG. 2 also adds a switch Q4 323 as compared to the circuit configuration shown in FIG. For the sake of simplicity, it is omitted here for the similarity in Figure 3. A description of the circuit portion shown in FIG.

As shown in FIG. 3, switch Q4 323 in the second circuit portion is coupled between nodes 6 and 4 in parallel with capacitor C2 322.

When the auxiliary circuit is not coupled to the main circuit, that is, when the input voltage does not exceed the predetermined range, the switch Q4 323 can be turned on by the controller, thereby short-circuiting the capacitor C2 322, shielding the current from flowing through the C2 322 and its corresponding The impedance, inductance and other factors on the auxiliary circuit affect the entire circuit, which is more beneficial to the energy transfer in the circuit system.

4 illustrates a circuit diagram of a DC-DC transformer device in accordance with yet another embodiment of the present invention.

As shown in FIG. 4, the DC-DC transformer device 400 includes a DC power source, a first circuit portion, a second circuit portion, and a third circuit portion.

The first circuit portion includes a switch Q1 411, a transformer 413, a diode 414, and a capacitor 412. In this context, the first circuit is also referred to as an auxiliary circuit. Thus, throughout the specification, the terms "first circuit portion" and "auxiliary circuit" are used interchangeably. The second circuit portion includes a capacitor C1 421, a capacitor C2 422, and a load resistor 423. The third circuit portion includes a switch Q2 431, a switch Q3 432, a transformer 436, an inductor 434, and a capacitor 435. In this context, the third circuit portion is also referred to as the "main circuit." Therefore, throughout the specification, the terms "third circuit portion" are used interchangeably with "main circuit."

As shown in Figure 4, the first circuit portion is coupled to the two outputs of the DC power source. In the first circuit portion, a capacitor 412 is coupled between node 1 and node 2. The primary side of the inductor 413 is connected in series with the switch Q1 411, and the two are also coupled between the node 1 and the node 2. The capacitor 412 is used to buffer the circuit system when the input voltage fluctuates greatly, and to stabilize the waveform of the input voltage.

In the second circuit portion, the load resistor 423 is coupled between the node 3 and the node 6. capacitance C2 422 is coupled between node 3 and node 4. Node 4 is coupled via diode 414 to one of the secondary sides of transformer 413. Node 3 is connected to the other end of the secondary side of transformer 413. Capacitor C1 421 is coupled between node 5 and node 6.

In the third circuit portion, the capacitor 433 is connected to both ends of the direct current power source. Switch Q2 431 is coupled between node 8 and node 10. Switch Q3 432 is coupled between node 9 and node 10. One end of the inductor 434 is coupled to the node 10 and the other end is coupled to one end of the transformer 436. The other end of transformer 436 is coupled to node 9 via capacitor 435.

The secondary side of transformer 436 can include a plurality of secondary side portions. As shown in the embodiment of FIG. 4, the secondary side of transformer 436 can include, for example, two secondary side portions 437, 438. One output of the secondary side portion 437 is coupled to the node 7 via a diode 439. One output of the secondary side portion 438 is also coupled to the node 7 via another diode 430. The secondary side portions 437, 438 share an output and the shared output is coupled to the node 5.

In the embodiment of FIG. 4, the input range of the DC power source Vin may be, for example, 36V to 72V. Assuming that the constant output voltage of the DC-DC converter is expected to be 12V, the output gain is 1/3 to 1/6. However, considering that the transformer 436 has a variation ratio of 3, the gain change rate (i.e., the ratio of the maximum gain to the minimum gain) ranges from 2 to 1. Due to the characteristics of the LLC line, if the gain change rate range is set to 2 to 1, it is difficult to obtain a good effect in the full gain range because the gain change rate is relatively large.

The gain change rate of the half-bridge LLC line is now set to 1 to 1.5, that is, the predetermined input voltage range is 48V to 72V, and the output voltage is 12V. In addition, if the voltage system 36 is input, it means that the range of 48V to 72V is exceeded. In order to ensure normal operation even if the input voltage exceeds a predetermined input voltage range (ie, 48V to 72V), in addition to the capacitor C1 421, a capacitor C2 422 is provided to provide an additional supplemental voltage in the embodiment of the present invention. .

Specifically, at a predetermined voltage range of 48V to 72V, a constant voltage is required to be output. 12V, therefore, the output gain ranges from 1/4 to 1/6. In the case where the output gain range is 1/4 to 1/6, if the input voltage is 36V (beyond the predetermined voltage range of 48V to 72V), the output voltage of the transformer device is 9V at the maximum.

In order to ensure a constant output voltage of 12V, an additional capacitor must be provided to provide a 3V offset voltage to maintain the output voltage at 12V. In the circuit system shown in Fig. 4, voltage compensation is realized by paralleling an auxiliary circuit on the main circuit.

When the input voltage (eg, 36V) exceeds the predetermined voltage range of 48V to 72V, the capacitor C2 422 is coupled into the circuitry by paralleling the third circuit portion to the first circuit portion. At this time, the voltage on the capacitor C1 421 is 9V. By setting the voltage on capacitor C2 422 to 3V, the output voltage at the output is guaranteed to be 12V. Of the total output energy, 1/4 of the energy is transferred to the second circuit portion via the first circuit portion.

When the input voltage falls within a predetermined input voltage range, the switch Q1 411 is opened by a controller (not shown), thereby disconnecting the auxiliary circuit such that the capacitor C2 422 is not coupled into the circuit system (ie, The auxiliary circuit does not work).

When the input voltage exceeds the predetermined input voltage range, the auxiliary circuit is coupled to the main circuit by the controller controlling the switch Q1 to be turned on and off alternately at a certain frequency, whereby the capacitor C2 422 is coupled to the circuit system. To provide a supplemental voltage at the load output of the circuitry.

It can be seen that by providing an auxiliary circuit, part of the input energy can be adjusted to adapt to a narrower predetermined input range, thereby improving the efficiency of the entire circuit system.

Additionally, in an embodiment of the invention, the determination of whether the input voltage falls within a predetermined input voltage range can be achieved by control logic. For example, the control logic can be a control component implemented using an electronic device such as a microcontroller. When the input voltage is judged, the input voltage can be detected, and then according to the threshold value, it is judged whether the input voltage falls under the increase of the main circuit. The range of values calculated from the range of benefits. If it falls within the range of voltage values, the auxiliary circuit is connected. If it does not fall within the range of voltage values, the auxiliary circuit is not connected.

In the embodiment of the present invention, the threshold for determining whether the input voltage falls within the range of the voltage value may be a range, and is not limited to a fixed value, so as to prevent the switching device from being frequently turned on and off. In an embodiment of the invention, the threshold may include a first threshold and a second threshold, and when the input voltage is higher than the first threshold, the auxiliary circuit is coupled to the main circuit, and When the input voltage is lower than the second threshold, the auxiliary circuit is disconnected from the main circuit. Although the lower limit of the predetermined voltage input range is defined herein as two threshold values, it should be understood that the number of the threshold values is not limited thereto, but may be any number.

In the circuit system shown in FIG. 4, when the auxiliary circuit inputs energy to the second circuit portion, no energy is required to be transferred from the second circuit portion to the main circuit. Because if there is energy in and out of the second circuit portion at the same time, there is no way to control the proportion of the energy flowing through the first circuit portion in the total energy.

FIG. 5 exemplifies a current waveform diagram when the auxiliary circuit performs energy output and a waveform diagram of current when the main circuit performs energy output to the capacitor C1 421. I_part1 indicates that the auxiliary circuit inputs energy to the capacitor C2 422, and I_part3 indicates that the main circuit outputs energy to the capacitor C1 421.

By controlling the switch Q1 411 in the auxiliary circuit shown in FIG. 4, the waveform I_part1 and the waveform I_part3 in FIG. 5 can be shifted in phase.

Specifically, in the case where the auxiliary circuit is coupled to the main circuit, that is, when the switch Q1 411 is turned on and off alternately, the frequency of the switch Q1 411 can be controlled by the controller so that the first circuit portion does not When the capacitor C2 422 in the second circuit portion transfers energy, the third circuit portion outputs energy to the C1 421 in the second circuit.

The frequency of the switch Q1 411 can also be controlled by the controller so that the first circuit portion is When the capacitor C2 422 in the two circuit portions transfers energy, the third circuit portion does not output energy to the capacitor C1 421 in the second circuit portion.

That is, when the capacitor C1 421 is charged by the third circuit portion, the capacitor C2 422 is discharged; and when the capacitor C2 422 is charged by the first circuit portion, the capacitor C1 421 is discharged. Thus, capacitor C1 421 and capacitor C2 422 operate alternately, staggering in phase.

When the output of the auxiliary circuit is coupled to the output of the main circuit, if the phase is not shifted, the current on the main circuit and the auxiliary circuit will be distributed according to the ratio of the resistance value of the secondary side of the transformer. Thereby, the waveform I_part1 is shifted from the waveform I_part3, so that the magnitude of the current flowing through the first circuit portion can be easily controlled without being affected by the resistance ratio.

On the other hand, when the output of the auxiliary circuit is coupled to the output of the main circuit, if it is not staggered in phase (that is, there is a case of phase overlap), the efficiency of the entire circuit (ie, the total efficiency of the auxiliary circuit and the main circuit, efficiency = output) The calculation of the electricity/input power is multiplied. For example, if the efficiency of the auxiliary circuit is 70% and the efficiency of the main circuit is 90%, the total efficiency when the phases overlap is: auxiliary circuit efficiency × main circuit efficiency = 70% × 90% = 63%. If the phase is completely staggered (that is, there is no phase overlap at all), the total efficiency is: (a × auxiliary circuit efficiency + b × main circuit efficiency) / (a + b) = 70% to 90%, wherein a is the time when the auxiliary circuit outputs to the output end of the main circuit (that is, the length of time that the auxiliary circuit inputs energy to the capacitor C2 422), b is the time of the output of the main circuit (that is, the length of time that the main circuit outputs energy to the capacitor C1 421). It can be seen that when the output of the auxiliary circuit is coupled to the output of the main circuit, the overall efficiency of the phase shifting (ie, the case where there is no phase overlap at all) is higher.

FIG. 6 illustrates a circuit diagram of a parallel mode DC-DC voltage transformer according to another embodiment of the present invention. The circuit configuration of the DC-DC converting device illustrated in Fig. 6 is substantially similar to the circuit configuration of the DC-DC converting device illustrated in Fig. 4. However, the circuit configuration shown in FIG. 6 also adds switch Q4 624 as compared to the circuit configuration shown in FIG. For the sake of simplicity, save the right here. A description of the circuit portion similar to that shown in Fig. 1 is shown in Fig. 6.

As shown in FIG. 6, switch Q4 624 is coupled between nodes 3 and 4 in parallel with capacitor C2 622.

When the auxiliary circuit is not coupled to the main circuit, that is, when the input voltage does not exceed the predetermined range, the switch Q4 624 can be turned on by the controller, thereby short-circuiting the capacitor C2 622, shielding the current from flowing through the C2 622 and its corresponding The impedance, inductance and other factors on the auxiliary circuit affect the entire circuit, which is more beneficial to the energy transfer in the circuit system.

The case where the adaptive voltage range of the main circuit is greater than or equal to the upper limit of the input voltage is described in the above embodiments. However, it should be understood that the upper limit of the adaptive voltage range of the main circuit may also be lower than the upper limit of the input voltage. If the upper limit of the adaptive voltage range of the main circuit is lower than the upper limit of the input voltage, it can be appropriately adjusted according to the above content, and can be implemented, but if the input voltage is at a position above the upper limit of the main circuit adaptation voltage range, it is necessary to The adjustment applies a negative voltage to C2, and the auxiliary circuit does not transfer energy to the main circuit, but instead returns the energy of the main circuit back to the auxiliary circuit, thus causing a certain loss, so the embodiment is more efficient.

In an embodiment of the invention, the DC voltage source is an electronic device capable of providing a stable DC power supply voltage to the load. For example, a dry battery, a battery, a DC generator, or the like can be used.

In an embodiment of the invention, the switch may employ a field effect transistor that is widely used in analog circuits and digital circuits, such as metal-oxide semiconductor field effect transistors (MOSFETs). Among them, MOSFETs can be classified into two types, N-type and P-type, depending on the polarity of their working carriers. They are also commonly referred to as NMOSFETs and PMOSFETs.

In an embodiment of the invention, "controller" or "control logic" may be implemented by hardware or software. For example, "controller" or "control logic" can be implemented in one or more of the following: general purpose processors, digital signal processors (DSPs), special application integrated circuits (ASIC), Field Programmable Gate Array Signal (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

When implemented in software, the "controller" or "control logic" can be implemented with firmware, middleware, or microcode. The code or code segments that perform the necessary tasks can be stored in a computer readable or processor readable medium such as a storage medium or other storage. The processor can perform these necessary tasks. A code segment can represent a program, a function, a subroutine, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment can be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including storage sharing, messaging, token passing, network transmission, and the like.

In the description of the present invention, the term "coupled" may refer to a direct connection between components, and may also refer to an indirect connection between components. In addition, the term "coupled" may refer not only to a wired connection, but also to a wireless connection, and may even cover various other connections.

In the description of the present invention, "charging" may refer to the flow of energy into an energy storage element such as a capacitor. "Discharge" can refer to the flow of energy from an energy storage element such as a capacitor.

While the various embodiments of the invention have been described, it is understood that It will be apparent to those skilled in the art that various changes can be made without departing from the spirit and scope of the invention. Accordingly, the invention disclosed herein is The breadth and scope should not be limited by the exemplary embodiments disclosed above, but only by the scope of the appended claims and their equivalents.

Claims (21)

A DC-DC transformer device includes: a DC voltage source, an output DC power supply voltage; a main circuit for converting an input voltage into an output voltage having a set value; and an auxiliary circuit coupled to the DC voltage source for Coupling to the main circuit when the input voltage fluctuation exceeds a predetermined range, so that the output voltage is maintained at the output voltage having the set value; wherein the input voltage fluctuation range is outside the predetermined range and the value is less than the upper limit of the predetermined range The difference between the lower limits. A DC-DC transformer device of claim 1, wherein coupling the auxiliary circuit to the main circuit comprises coupling the auxiliary circuit to an input of the main circuit when the input voltage exceeds the predetermined range. The DC-DC transformer device of claim 2, further comprising a first energy storage circuit and a second energy storage circuit, wherein the two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, Both ends of the first tank circuit are connected to the output of the DC voltage source, and wherein when the auxiliary circuit is coupled to the main circuit, the auxiliary circuit charges the second tank circuit and stores the second The energy in the tank circuit will then be transferred to the load via the main circuit. A DC-DC transformer device comprising: a DC voltage source, an output DC power supply voltage; a main circuit for converting an input voltage into an output voltage having a set value; an auxiliary circuit coupled to the DC voltage source for coupling when the input voltage fluctuates beyond a predetermined range Connecting to the main circuit to maintain an output voltage at the output voltage having a set value; wherein coupling the auxiliary circuit to the main circuit when the input voltage exceeds the predetermined range comprises coupling the auxiliary circuit to the The output of the main circuit. A DC-DC voltage transformer of claim 1 or 4, wherein the nominal upper limit of the input voltage fluctuation is equal to an upper limit of the predetermined range. The DC-DC transformer device of claim 4, further comprising a first energy storage circuit and a second energy storage circuit, wherein the two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, the first Both ends of a tank circuit are coupled to the output of the main circuit, and wherein the second tank circuit provides an additional supplemental voltage to the load output when the auxiliary circuit is coupled to the main circuit. The DC-DC voltage transformer of claim 3 or 6, wherein the first energy storage circuit and the second energy storage circuit are capacitors. The DC-DC transformer device of claim 7, further comprising a controller that controls charging and discharging of the second tank circuit by the main circuit and the auxiliary circuit, and wherein the controller controls the auxiliary circuit to the When the second storage circuit is charged, the main circuit does not discharge the second energy storage circuit, or the controller controls the auxiliary circuit to charge the second energy storage circuit, the main circuit is not the second storage Can charge the circuit. The DC-DC transformer device of claim 7, further comprising a switch in parallel with the second tank circuit, the switch being turned on when the input voltage does not exceed the predetermined range. The DC-DC transformer device of claim 5, wherein the lower limit of the predetermined range includes a first threshold and a second threshold, and when the input voltage is higher than the first threshold, the auxiliary circuit The main circuit is coupled to the main circuit, and when the input voltage is lower than the second threshold, the auxiliary circuit is disconnected from the main circuit. The DC-DC transformer device of claim 7, wherein the auxiliary circuit comprises an auxiliary transformer and an auxiliary switch, wherein the transformer and the auxiliary switch are connected in series to the two output terminals of the DC voltage source. A DC-DC transformer device as claimed in claim 7, wherein the main circuit comprises a half bridge LLC circuit comprising a main transformer. A method for controlling a DC-DC transformer device to output a constant voltage, the DC-DC transformer device comprising a main circuit and an auxiliary circuit, the method comprising: detecting an input voltage; determining whether the detected input voltage falls Within the predetermined range; and if the detected input voltage falls within a predetermined range, the auxiliary circuit is coupled to the main circuit by a control switch; The coupling the auxiliary circuit to the main circuit includes coupling the auxiliary circuit to an output of the main circuit. The method of claim 13, wherein coupling the auxiliary circuit to the main circuit comprises coupling the auxiliary circuit to an input of the main circuit. The method of claim 13, wherein the main circuit comprises a half bridge LLC circuit. The method of claim 13, wherein the auxiliary circuit comprises an auxiliary transformer and a first auxiliary switch. The method of claim 16, wherein the auxiliary circuit is coupled to the main circuit when the first auxiliary switch is turned on and off at a certain frequency, and the auxiliary circuit is not Coupled to the main circuit. The method of claim 14, wherein the DC-DC transformer device also includes a first energy storage circuit (C1) and a second energy storage circuit (C2), two output terminals of the auxiliary circuit and the second energy storage circuit The two terminals are electrically connected, the two ends of the first energy storage circuit are connected to the output end of the DC voltage source, and wherein the auxiliary circuit charges the second energy storage circuit when the auxiliary circuit is coupled to the main circuit And the energy stored in the second tank circuit will then be transmitted to the load via the main circuit. The method of claim 13, wherein the DC-DC transformer device further comprises a first energy storage circuit (C1) and a second energy storage circuit (C2), the two output ends of the auxiliary circuit are electrically connected to two terminals of the second energy storage circuit, and the two ends of the first energy storage circuit are connected to the output end of the main circuit And wherein the second tank circuit provides an additional supplemental voltage to the load output when the auxiliary circuit is coupled to the main circuit. The method of any one of claims 18 to 19, further comprising a switch in parallel with the second tank circuit, the switch being turned on when the input voltage does not exceed the predetermined range. The method of claim 20, wherein the controller is used to control charging or discharging of the second tank circuit by the main circuit and the auxiliary circuit, including using the controller to control the auxiliary circuit to charge the second tank circuit The main circuit does not charge the second tank circuit when the main circuit does not discharge the second tank circuit or when the controller is used to control the auxiliary circuit to charge the second tank circuit.