CN110247546A - Non-isolation type biswitch reduction voltage circuit and DC-DC converter - Google Patents

Abstract

The embodiment of the invention provides a kind of non-isolation type biswitch reduction voltage circuit and DC-DC converters, reduction voltage circuit includes positive input terminal, positive output end, negative input end, negative output terminal, first switch tube, the first inductance, first diode and filter unit, the reduction voltage circuit further includes partial pressure unit and discharge paths, in which: the first switch tube, the first inductance, partial pressure unit are connected in series between the positive input terminal and positive output end；The anode of the first diode is connected to the negative input end, cathode is connected to the tie point of the first switch tube and the first inductance；The partial pressure unit includes at least one storage capacitor, and the energy storage when the first switch tube is connected of first inductance and the storage capacitor, and is discharged when the first switch tube is disconnected by the discharge paths.The present invention improves switching device utilization rate, realizes multilevel decompression effect.

Description

Non-isolated double-switch step-down circuit and DC-DC converter

technical field

The invention relates to the field of electronic technology, and more specifically, relates to a non-isolated double-switch step-down circuit and a DC-DC converter.

Background technique

The DC-DC converter is the key equipment in the medium-voltage convergence network to match the voltage level, connect to the DC equipment, and realize power control. The DC-DC converter includes a step-down circuit (buck).

The traditional buck circuit generally adopts the following methods to step down: store and release energy through the inductor, control the storage time, and achieve the purpose of stepping down; through the coupled inductor, the turns ratio of the coupled inductor is added to the step-down ratio of the original circuit This control variable achieves the purpose of further step-down; by adding a transformer, an isolated step-down circuit is formed to achieve the purpose of step-down and electrical ionization; step-down is performed through a linear voltage regulator.

However, there are certain problems in the application of the traditional step-down circuit (buck) mentioned above: the step-down circuit using an inductor, in the case of a high step-down ratio, that is, when the duty cycle of the switch tube tends to zero, there is a switch Low device utilization, large device voltage and current stress, serious EMI caused by large dv/dt, excessive overall circuit loss, poor resistance to input voltage disturbance, and poor dynamic performance; use coupled inductors or transformers for step-down circuits , due to the addition of magnetic cores and skeletons, the circuit volume is too large, and the device stress increases due to the existence of circuit leakage inductance, and it is easy to cause related problems such as electromagnetic interference; Under the required conditions, the loss is too large, and the device generates serious heat.

Contents of the invention

The technical problem to be solved in the embodiments of the present invention is to provide a non-isolated Double-switch step-down circuit and DC-DC converter.

The technical solution of the embodiments of the present invention to solve the above technical problems is to provide a non-isolated double-switch step-down circuit, including a positive input terminal, a positive output terminal, a negative input terminal, a negative output terminal, a first switch tube, a second An inductor, a first diode, and a filter unit, the step-down circuit also includes a voltage dividing unit and a discharge branch, wherein: the first switch tube, the first inductor, and the voltage dividing unit are connected in series to the positive input terminal and the positive output terminal; the anode of the first diode is connected to the negative input terminal, and the cathode is connected to the connection point of the first switching tube and the first inductor; the voltage dividing unit includes at least one storage energy capacitor, and the first inductor and the energy storage capacitor store energy when the first switch tube is turned on, and discharge through the discharge branch when the first switch tube is turned off.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the discharge branch includes a second switch tube, one end of the second switch tube is connected to the negative input terminal, and the other end is connected to the negative input terminal. The connection point between the first inductor and the voltage dividing unit, and the second switch tube is turned off when the first switch tube is turned on, and is turned on when the first switch tube is turned off.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the step-down circuit further includes a control unit, and the output terminals of the control unit are respectively connected to the first switch tube and the second switch tube. control terminal, and output a pulse width modulation signal that makes the conduction states of the first switch tube and the second switch tube reverse.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the voltage dividing unit includes a first energy storage capacitor, and the first terminals of the first energy storage capacitor are respectively connected to the first inductor The output terminal of the first energy storage capacitor is connected to the filter unit with the cathode of the second switching tube.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the voltage dividing unit includes a second energy storage capacitor, a third energy storage capacitor, a second diode, a third diode and a fourth A diode; the second energy storage capacitor, the second diode and the third energy storage capacitor are connected in series, the first end of the second energy storage capacitor is connected to the first inductor, and the third energy storage capacitor The second end of the energy storage capacitor is connected to the filter unit, and the anode of the second diode is connected to the second end of the second energy storage capacitor, and the cathode is connected to the first end of the third energy storage capacitor connected, the cathode of the third diode is connected to the first end of the second energy storage capacitor, the anode is connected to the first end of the third energy storage capacitor, and the cathode of the fourth diode is connected to To the second terminal of the second energy storage capacitor, the anode is connected to the filtering unit.

In the non-isolated double-switch step-down circuit described in the embodiment of the present invention, the voltage dividing unit includes N energy storage capacitors and M diodes, where N is a positive integer greater than or equal to 3, and M =3×N-3; the N energy storage capacitors are sequentially connected in series in the form of a diode between adjacent energy storage capacitors; except for the energy storage capacitor whose first end is directly connected to the first inductance, the rest The first end of each energy storage capacitor is connected to the first inductance via a diode; except that the second end is directly connected to the energy storage capacitor of the filter unit, the filter unit is respectively connected to the remaining capacitors through a diode The second terminal of each energy storage capacitor.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the step-down circuit further includes a second inductor and a fifth diode, and the output terminal of the voltage dividing unit is connected via the fifth diode The tube is connected to the positive output end, the first end of the second inductance is connected to the connection point of the voltage dividing unit and the fifth diode, the second end of the second inductance is connected to the negative input.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the step-down circuit further includes a third inductor and a sixth diode, and the output terminal of the voltage dividing unit is connected to To the positive output terminal, the cathode of the sixth diode is connected to the connection point of the voltage dividing unit and the third inductor, and the anode of the sixth diode is connected to the negative input terminal.

In the non-isolated double-switch step-down circuit according to the embodiment of the present invention, the filter unit includes a filter capacitor, and the first terminal of the filter capacitor is connected to the positive output terminal, and the second terminal is connected to the Negative output terminal.

An embodiment of the present invention also provides a DC-DC converter, the DC-DC converter comprising the non-isolated double-switch step-down circuit in any of the above embodiments.

The non-isolated double-switch step-down circuit and the DC-DC converter of the embodiment of the present invention, by introducing a capacitive voltage divider unit in the step-down circuit, do not need coupling inductors or transformers, avoiding excessive loss and electromagnetic interference caused by the introduction of magnetic components. Problems such as interference and circuit leakage inductance have improved the problem of the duty cycle limit of the traditional step-down circuit switch tube, improved the utilization rate of the switch device, and realized the multi-stage step-down effect. At the same time, by increasing the number of voltage-dividing capacitors and diodes, a multi-stage voltage-dividing unit is further introduced to realize the function of continuously controlling the output voltage by the duty cycle of the switch tube. It has a variety of different voltage-reducing effects and can be selected according to actual applications. , broaden the scope of application of the step-down circuit.

Description of drawings

Fig. 1 is a non-isolated double-switch step-down circuit topology diagram of an embodiment of the present invention;

Fig. 2 is a working waveform diagram of a voltage-dividing type non-isolated double-switch step-down circuit of an embodiment of the present invention;

3 is a topological diagram of a voltage-dividing non-isolated double-switch step-down circuit according to an embodiment of the present invention;

Fig. 4 is a diagram of the first working mode of a voltage-dividing non-isolated double-switch step-down circuit according to an embodiment of the present invention;

Fig. 5 is a diagram of the second working mode of a voltage-dividing non-isolated double-switch step-down circuit according to an embodiment of the present invention

6 is a topological diagram of a two-divider non-isolated double-switch step-down circuit according to an embodiment of the present invention;

7 is a diagram of the first working mode of the two-divider non-isolated double-switch step-down circuit according to the embodiment of the present invention;

8 is a second working mode diagram of the two-divider non-isolated double-switch step-down circuit according to the embodiment of the present invention;

9 is a topological diagram of an N-divider non-isolated double-switch step-down circuit according to an embodiment of the present invention;

10 is a topological diagram of a voltage-dividing non-isolated double-switch step-down circuit according to another embodiment of the present invention;

Fig. 11 is a topological diagram of a two-divider non-isolated double-switch step-down circuit according to another embodiment of the present invention;

FIG. 12 is a topological diagram of an N-divided non-isolated double-switch step-down circuit according to another embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the embodiments of the present invention, and are not intended to limit the embodiments of the present invention.

The non-isolated double-switch step-down circuit of the embodiment of the present invention can be applied to high step-down application scenarios. As shown _in FIG. Terminal V _o +, negative input terminal V _in -, negative output terminal V _o -, the first switch tube S ₁ , the first inductor L ₁ , the first diode D ₁ and the filter unit, the step-down circuit also includes A voltage dividing unit 1 and a discharge branch, wherein: the first switch tube S ₁ , the first inductor L ₁ , and the voltage dividing unit 1 are connected in series between the positive input terminal V _in + and the positive output terminal V _o +; The anode of the first diode D ₁ is connected to the negative input terminal V _in -, and the cathode is connected to the connection point of the first switching tube S ₁ and the first inductor L ₁ ; the voltage dividing unit 1 includes At least one energy storage capacitor, the discharge branch discharges the first inductor L ₁ and the energy storage capacitor when the first switch tube S ₁ is turned off. The filter unit includes a filter capacitor C ₀ , and a first end of the filter capacitor C ₀ is connected to the positive output terminal V _o +, and a second end is connected to the negative output terminal V _o −.

The above-mentioned non-isolated double-switch step-down circuit, by introducing a capacitive voltage divider unit on the basis of the traditional step-down circuit, can achieve a step-down effect while providing a high step-down ratio without coupling inductors or transformers, thereby avoiding switching Problems such as low device utilization and circuit leakage inductance.

In one embodiment of the present invention, the discharge branch above may specifically include a second switch tube S ₂ , the anode of the second switch tube S ₂ is connected to the negative input terminal V _in -, and the cathode is connected to the first The connection point between the inductor L ₁ and the voltage dividing unit 1, and the conduction state of the second switching tube S ₂ is opposite to that of the first switching tube S ₁ , that is, the first switching tube S ₁ and the second switching tube S ₂ The driving signal is a complementary signal, and the working waveform diagram of the specific circuit is shown in Figure 2. In the figure, V _gs1 is the control signal of the _first switching tube S1, V _gs2 is the control signal of the second switching tube S2, and the waveforms of V _gs1 and V _gs2 are complementary, that is, when the _first switching tube S1 is turned on, the second The switch tube S2 is turned off, and the _second switch tube S2 is turned _on when the _first switch tube S1 is turned off.

The above-mentioned _first switching tube S1 and _second switching tube S2 can realize on-off control through a pulse width modulation signal, that is, the step-down circuit also includes a control unit, and the output terminals of the control unit are respectively connected to the first switching tube S ₁ and the control terminal of the _second switch tube S2, and the control unit outputs a pulse width modulation signal that makes the conduction states of the _first switch tube S1 and the _second switch tube S2 reverse, so as to control the first switch tube S ₁ and the turn-on and turn-off of the _second switch tube S2.

The above step-down circuit may further include a second inductor L _o and a fifth diode D ₂ , the output terminal of the voltage dividing unit 1 is connected to the positive output terminal V _o + via the fifth diode D ₂ , the first end of the second inductance L _o is connected to the connection point of the voltage dividing unit 1 and the fifth diode D2, the _second end of the second inductance L _o is connected to the negative Input terminal V _o -. By controlling the working states of the _first switching tube S1 and the _second switching tube S2, the _second inductor L _o and the fifth diode D2 realize charging or discharging of the energy storage capacitor.

As shown in FIG. 3 , the embodiment of the present invention provides a voltage-dividing non-isolated double-switch step-down circuit, wherein a voltage-dividing unit 11 includes a first energy storage capacitor C ₁ , and the first energy storage The first end of the capacitor _C1 is respectively connected to the output end of the _first inductor L1 and the cathode of the _second switching tube S2, and the second end of the first energy storage capacitor _C1 is connected to the filter unit. Specifically, by introducing the first energy storage capacitor C ₁ into a voltage-dividing non-isolated double-switch step-down circuit topology, wherein when the first switch S ₁ is turned on and the second switch S ₂ is turned off, a The first working mode of the voltage-dividing non-isolated double-switch step-down circuit is shown in Figure 4. The electric energy at the input terminal passes through the first switch tube S ₁ , the first inductor L ₁ , the first energy storage capacitor C ₁ and the fifth _The diode D2 transmits to the output terminal, the _second inductor L _o freewheels through the fifth diode D2, and the current drops. When the _first switch tube S1 is turned off and the _second switch tube S2 is turned on, the second working mode of a voltage-dividing non-isolated double-switch step-down circuit is shown in Figure 5, and the _first inductor L1 passes through The _second switch tube S2 freewheels, the first energy storage capacitor _C1 discharges through the second switch tube S2 and the _second inductor L _o , and the current of the second inductor L _o rises. The gain calculation formula of a voltage-dividing non-isolated double-switch step-down circuit is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

As shown in FIG. 6, the embodiment of the present invention provides a two-divider non-isolated double-switch step-down circuit, wherein the two-divider unit 12 includes a second energy storage capacitor C ₁ ', a third energy storage capacitor C ₂ ′, the second diode D ₃ ′, the third diode D ₄ ′, and the fourth diode D ₅ ′; the second energy storage capacitor C ₁ ′, the second diode D ₃ ′ And the third energy storage capacitor C ₂ ′ is connected in series, the first end of the second energy storage capacitor C ₁ ′ is connected to the first inductor L ₁ , the second end of the third energy storage capacitor C ₂ ′ connected to the anode of the fifth diode D ₂ , and the anode of the second diode D ₃ ′ is connected to the second end of the second energy storage capacitor C ₁ ′, and the cathode is connected to the third The first end of the energy storage capacitor C ₂ ′ is connected, the cathode of the third diode D ₄ ′ is connected to the first end of the second energy storage capacitor C ₁ ′, and the anode is connected to the third energy storage capacitor C ₂ ′, the cathode of the fourth diode D ₅ ′ is connected to the second end of the second energy storage capacitor C ₁ ′, and the anode is connected to the first end of the second inductor L _o one end. Wherein, the driving signals of the _first switching tube S1 and the _second switching tube S2 are consistent with a voltage-dividing non-isolated double-switch step-down circuit, and the output voltage still passes through the _first switching tube S1 and the second switching tube S ₂ The size of the duty cycle is adjusted. When the _first switch tube S1 is turned on and the _second switch tube S2 is turned off, the first working mode of the two-divider non-isolated double-switch step-down circuit is shown in Figure 7, and the electric energy at the input end passes through the second A switch tube S ₁ , the first inductance L ₁ , the second energy storage capacitor C ₁ ', the third energy storage capacitor C ₂ ' and the fifth diode D ₂ are transmitted to the output terminal, and the second inductance L _o passes through the fifth Diode D2 _freewheels and the current drops. When the _first switch tube S1 is turned off and the _second switch tube S2 is turned on, the second working mode of the two-divider non-isolated double-switch step-down circuit is shown in Figure 8, and the first inductor L1 passes through The second switch tube S ₂ freewheels, the second energy storage capacitor C ₁ ′, and the third energy storage capacitor C ₂ ′ are discharged through the second switch tube S ₂ and the second inductor L _o , and the current of the second inductor L _o rises. By adding an energy storage capacitor and three diodes to the one-divider non-isolated double-switch step-down circuit, the two-part non-isolated double-switch step-down circuit achieves the effect of halving the output voltage, that is, the same In the case of empty ratio, the output voltage becomes 1/2 of the original. The gain calculation formula of the two-divider non-isolated two-switch step-down circuit is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

As shown in FIG. 9 , an embodiment of the present invention provides an N voltage-dividing non-isolated double-switch step-down circuit, wherein the N voltage-dividing unit 13 includes N energy storage capacitors and M diodes. The N is a positive integer greater than or equal to 3, M=3×N-3; the N energy storage capacitors are sequentially connected in series with a diode between adjacent energy storage capacitors; except that the first end is directly connected To the energy storage capacitor C ₁ " of the first inductance L ₁ ", the first end of each of the remaining energy storage capacitors is connected to the first inductance L ₁ via a diode; except that the second end is directly connected to the The anode of the fifth diode D ₂ is connected to the _second end of _each of the remaining energy storage capacitors through a diode. Wherein, the driving signals of the _first switching tube S1 and the _second switching tube S2 are consistent with a voltage-dividing non-isolated double-switch step-down circuit, and the output voltage still passes through the _first switching tube S1 and the second switching tube S ₂ The duty cycle is adjusted. On the basis of a voltage-dividing step-down circuit, only by increasing the number of energy storage capacitors and diodes in the voltage-dividing unit, the N-divided non-isolated double-switch step-down circuit realizes output voltage reduction. It is one-nth of the original effect. The gain calculation formula of the N-divider non-isolated double-switch step-down circuit is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

As shown in Figure 10, based on the above-mentioned one-dividing type non-isolated double-switch step-down circuit, the present invention provides another embodiment of a voltage-dividing type non-isolated double-switch step-down circuit, the step-down circuit includes the first Three inductors L _o ', sixth diode D ₂ ', the output terminal of a voltage dividing unit 11 is connected to the positive output terminal V _o + via the third inductor L _o ', the sixth diode The cathode of D ₂ ′ is connected to a voltage dividing unit 11 and the connection point of the third inductor L _o ′, and the anode of the sixth diode D ₂ ′ is connected to the negative input terminal V _o −, or The step-down function of a similar circuit is realized, the difference is that the voltage output by a voltage dividing unit 11 is filtered by the third inductor L _o ', and then output to the filter capacitor C ₀ , that is, the filtering mode of the output terminal has changed. In addition, the gain calculation formula of the circuit of this embodiment is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

Correspondingly, as shown in FIG. 11 , on the basis of the one-division non-isolated double-switch step-down circuit shown in FIG. 10 , the present invention provides another embodiment of the two-divider non-isolated double-switch step-down circuit, The filtering method is consistent with that in Fig. 10, and the gain calculation formula of this embodiment is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

Correspondingly, as shown in FIG. 12 , on the basis of the one-division non-isolated double-switch step-down circuit shown in FIG. 10 , the present invention provides another embodiment N-divider non-isolated double-switch step-down circuit, The filtering method is consistent with that in Fig. 10, and the gain calculation formula of this embodiment is as follows:

Wherein, V _o is the output voltage, V _in is the input voltage, D ₁ is the duty cycle of the first switch S ₁ , and D ₂ is the duty cycle of the second switch S ₂ .

An embodiment of the present invention also provides a DC-DC converter, the DC-DC converter includes the non-isolated double-switch step-down circuit in any one of the above embodiments.

The non-isolated double-switch step-down circuit and the DC-DC converter of the embodiment of the present invention, by introducing a capacitive voltage divider unit in the step-down circuit, avoid the excessive loss and the introduction of linear regulators in the traditional step-down method. The problem of electromagnetic interference generated by magnetic components has improved the problem of the limitation of the duty cycle of the switch tube in the traditional step-down circuit, and realized the multi-stage step-down effect. At the same time, by increasing the number of voltage-dividing capacitors and diodes, a multi-stage voltage-dividing unit is further introduced to realize the function of continuously controlling the output voltage by the duty cycle of the switch tube. It has a variety of different voltage-reducing effects and can be selected according to actual applications. , broaden the scope of application of the step-down circuit.

The above is only a preferred specific implementation of the embodiment of the present invention, but the scope of protection of the embodiment of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope disclosed in the embodiment of the present invention, Easily conceivable changes or substitutions shall fall within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. a kind of non-isolation type biswitch reduction voltage circuit, including positive input terminal, positive output end, negative input end, negative output terminal, first Switching tube, the first inductance, first diode and filter unit, which is characterized in that the reduction voltage circuit further includes partial pressure unit And discharge paths, in which: the first switch tube, the first inductance, partial pressure unit are connected in series in the positive input terminal and just defeated Between outlet；The anode of the first diode is connected to the negative input end, cathode is connected to the first switch tube and The tie point of one inductance；The partial pressure unit includes at least one storage capacitor, and first inductance and the storage capacitor The energy storage in first switch tube conducting, and discharged when the first switch tube is disconnected by the discharge paths.

2. non-isolation type biswitch reduction voltage circuit according to claim 1, which is characterized in that the discharge paths include the Two switching tubes, one end of the second switch is connected to the negative input end, the other end is connected to first inductance and divides The tie point of unit is pressed, and the second switch disconnects when the first switch tube is connected, is disconnected in the first switch tube Conducting when opening.

3. non-isolation type biswitch reduction voltage circuit according to claim 2, which is characterized in that the reduction voltage circuit further includes Control unit, the output end of described control unit are connected respectively to the control terminal of the first switch tube and second switch, and Output makes the first switch tube and the opposite pulse width modulating signal of second switch on state.

4. non-isolation type biswitch reduction voltage circuit according to claim 3, which is characterized in that the partial pressure unit includes the One storage capacitor, and the first end of first storage capacitor is connected respectively to the output end and described second of first inductance The second end of the cathode of switching tube, first storage capacitor is connected to the filter unit.

5. non-isolation type biswitch reduction voltage circuit according to claim 3, which is characterized in that the partial pressure unit includes the Two storage capacitors, third storage capacitor, the second diode, third diode and the 4th diode；Second storage capacitor, Second diode and the connection of third energy storage capacitor in series, the first end of second storage capacitor are connected to first electricity Sense, the second end of the third storage capacitor are connected to the filter unit, and the anode of second diode and described the The second end connection of two storage capacitors, cathode are connect with the first end of the third storage capacitor, the yin of the third diode Pole is connected to the first end of second storage capacitor, anode is connected to the first end of the third storage capacitor, and the described 4th The cathode of diode is connected to the second end of second storage capacitor, anode is connected to the filter unit.

6. non-isolation type biswitch reduction voltage circuit according to claim 3, which is characterized in that the partial pressure unit includes N A storage capacitor and M diode, wherein the N is the positive integer more than or equal to 3, M=3 × N-3；N number of storage Energy capacitor is successively connected in series afterwards in a manner of having a diode between adjacent storage capacitor；In addition to first end is directly connected to Outside the storage capacitor of first inductance, the first end of remaining each storage capacitor is connected to described via a diode One inductance；Other than second end is directly connected to the storage capacitor of the filter unit, the filter unit passes through one respectively Diode is connected to the second end of remaining each storage capacitor.

7. according to the described in any item non-isolation type biswitch reduction voltage circuits of claim 4-6, which is characterized in that the decompression electricity Road further includes the second inductance, the 5th diode, and the output end of the partial pressure unit is connected to described via the 5th diode Positive output end, the first end of second inductance are connected to the tie point, described of the partial pressure unit and the 5th diode The second end of second inductance is connected to the negative input end.

8. according to the described in any item non-isolation type biswitch reduction voltage circuits of claim 4-6, which is characterized in that the decompression electricity Road further includes third inductance, the 6th diode, the output end of the partial pressure unit via the third inductance connection to it is described just The cathode of output end, the 6th diode is connected to the tie point of the partial pressure unit and the third inductance, the described 6th The anode of diode is connected to the negative input end.

9. according to the described in any item non-isolation type biswitch reduction voltage circuits of claim 4-6, which is characterized in that the filtering is single Member include filter capacitor, and the first end of the filter capacitor is connected to the positive output end, second end be connected to it is described bear it is defeated Outlet.

10. a kind of DC-DC converter, which is characterized in that the DC-DC converter includes appointing in claim 1-9 Non-isolation type biswitch reduction voltage circuit described in one.