WO2012106870A1

WO2012106870A1 - Method for improving efficiency of dc-dc conversion circuit and control apparatus for dc-dc conversion circuit

Info

Publication number: WO2012106870A1
Application number: PCT/CN2011/076907
Authority: WO
Inventors: 谢强; 宋伟
Original assignee: 华为技术有限公司
Priority date: 2011-07-06
Filing date: 2011-07-06
Publication date: 2012-08-16
Also published as: CN102308464A; CN102308464B

Abstract

A method for improving the efficiency of a DC-DC conversion circuit and a control apparatus for a DC-DC conversion circuit, the method comprising: while conducting and cutting off a plurality of MOSFET field effect transistors (M_P1, M_P2, M_P3, M_P4; M_N1, M_N2, M_N3) in the conversion circuit according to a preset period, detecting the current flowing through the induction coil (L₀) for energy storage and release in the conversion circuit; when the current flowing through the induction coil (L₀) is lower than the lower threshold of the preset current, delivering a control level to the gates of a part of the plurality of MOSFET field effect transistors (M_P1, M_P2, M_P3, M_P4; M_N1, M_N2, M_N3), thereby enabling the part of the MOSFET field effect transistors to stay in a cut-off state and no longer conducting according to the preset period. The method improves the efficiency of the conversion circuit in a light load state.

Description

Method for improving efficiency of DC-DC conversion circuit and DC-DC conversion circuit control device

The present invention relates to the field of DC-DC conversion circuits, and more particularly to a method for improving the efficiency of a DC-DC conversion circuit and a DC-DC conversion circuit control device.

Background technique

DC (D ir ec t Cur r en t, DC) - The DC conversion circuit converts the input DC voltage into an output DC voltage with a higher or lower voltage value for use by the load device. Figure 1 shows a common BUCK type DC-DC converter circuit that converts the input DC voltage to an output DC voltage with a lower voltage value. In Figure 1, V _in is the input DC voltage, V. The output DC voltage generated after the DC-DC conversion is applied to the load device. R. Is the equivalent resistance of the load device. N ( N > 2 ) P-channel MOSFETs (field effect transistors) are connected in parallel between point a and point b on the circuit, and M ( M > 2 ) N-channels are connected in parallel between point c and point b. Type MOSFET. The N P-channel MOSFETs and the M N-channel MOSFETs are power M0 SFETs of a DC-DC conversion circuit. The inductor L is connected in series with each power MOSFET. When the N P-channel MOSFETs are turned on and the M N-channel type MO SFETs are turned off, the inductor L stores energy; when the N P-channel MOS FETs are turned off, M N-channel MOSFETs When turned on, the inductor L releases the stored energy. The transistor controller 1 1 is electrically connected to all of the power MOSFETs to control the on and off of the power MOSFET, so that the P-channel type MO SFET and the N-channel MOSFET as the power MO SFET are sequentially turned on according to a predetermined cycle. State, and make the circuit output a stable V. Give the load device 1 2 .

In the process of implementing the above solution, the inventors have found that the prior art has at least the following problems: When the output power of the DC-DC conversion circuit is low, the power MOS FET frequently turns on and off, which causes charging and discharging of the gate capacitance. The loss increases and the current I flows through the load device. Below the preset light load current value, the load device is in a light load state. At this time, the charge and discharge loss of the gate capacitance of the power MOS FET does not decrease, resulting in the efficiency of the DC-DC conversion circuit (load The ratio of the power on the device to the total power of the DC-DC converter circuit is reduced, and the power is wasted more.

Summary of the invention

Embodiments of the present invention provide a method and a DC-DC conversion circuit control device for improving the efficiency of a DC-DC conversion circuit, which improve the efficiency of a DC-DC conversion circuit under light load conditions.

In order to achieve the above object, the embodiment of the present invention adopts the following technical solutions:

A method for improving the efficiency of a DC-DC conversion circuit, comprising: detecting, flowing through the DC-DC conversion circuit while turning on and off a plurality of MOSFET field effect transistors in a DC-DC conversion circuit according to a predetermined period Current for energy storage and release of the inductor coil;

When the current flowing through the inductor coil is lower than a preset lower current threshold, the plurality of

The gate of a portion of the MOSFET field effect transistor in the MOSFET field effect transistor delivers a control level such that the portion of the MOSFET field effect transistor is continuously turned off and is no longer turned on for a predetermined period.

A DC-DC conversion circuit control device includes:

a level control unit, configured to control on and off of the plurality of MOSFET field effect transistors in the DC-DC conversion circuit according to a predetermined period;

a current detecting unit, configured to detect an inductance flowing through the DC-DC conversion circuit for energy storage and release while turning on and off a plurality of MOSFET field effect transistors in the DC-DC conversion circuit according to a predetermined period Current of the coil;

The level control unit is further configured to: when the current flowing through the inductor is lower than a preset current lower threshold, transmit control power to a gate of a part of the MOSFET field effect transistors of the plurality of MOSFET field effect transistors Flat, so that the portion of the MO SFET field effect transistor is continuously turned off, and is no longer turned on according to a predetermined period.

The method for improving the efficiency of a DC-DC conversion circuit and the DC-DC conversion circuit control device provided by the embodiments of the present invention, by detecting the current in the inductor coil, and when the current of the inductor coil is lower than a preset current lower limit threshold MO SFET delivers control point levels such that the portion The MOSFET is in an off state, which avoids the gate capacitance charge and discharge loss caused by the partial MOSFET during the periodic opening and closing operations, thereby improving the efficiency of the DC-DC conversion circuit under light load conditions.

DRAWINGS

1 is a schematic diagram of a BUCK type DC-DC conversion circuit in the prior art; FIG. 2 is a flowchart of a method for improving the efficiency of a DC-DC conversion circuit according to an embodiment of the present invention; FIG. 3 is an embodiment of the present invention. A schematic diagram of a synchronous rectification BUCK type DC-DC conversion circuit provided with a method for improving the efficiency of a DC-DC conversion circuit;

4 is a schematic diagram of a non-synchronous rectification BUCK type DC-DC conversion circuit using the method for improving the efficiency of a DC-DC conversion circuit according to an embodiment of the present invention;

5 is a schematic diagram of a synchronous rectification BOOST type DC-DC conversion circuit using the method for improving the efficiency of a DC-DC conversion circuit provided by an embodiment of the present invention;

6 is a schematic diagram of a non-synchronous rectified BOOST type DC-DC conversion circuit using the method for improving the efficiency of a DC-DC conversion circuit provided by an embodiment of the present invention;

7 is a block diagram of a DC-DC conversion circuit control apparatus according to an embodiment of the present invention;

8 is a non-synchronous rectification in which a DC-DC conversion circuit control device is located in an embodiment of the present invention;

Schematic diagram of a BUCK type DC-DC converter circuit.

Detailed ways

In the DC-DC conversion circuit, there is a transistor controller that controls the power MOSFET to be turned on and off at a predetermined cycle. Taking FIG. 1 as an example, the transistor controller 11 is electrically connected to the gates of respective N-channel type and P-channel MOSFETs as power MS0FETs. The transistor controller 11 controls the N-channel type and P-channel type MOSFETs to be alternately turned on by supplying a level signal to the power MOSFET. Specifically, in a predetermined period T, the transistor controller 11 outputs a level to the gate of the MOSFET, so that the voltage difference between the gate and the source of the N P-channel MOSFETs in the circuit becomes zero. The P-channel MOSFET is turned off, and the gate output level of the M N-channel MOSFETs is controlled to control the N-channel MOSFET. The on state, the duration is TKT); after L, the transistor controller 1 1 turns off the N-channel MOSFET through the level output, and simultaneously turns the P-channel MOSFET into a conducting state, and the duration is TL. . Thereby, alternating conduction of the N-channel type MOSFET and the P-channel type MOSFET is realized. The technical solutions of the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings of the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention. Example 1:

Embodiments of the present invention provide a method for improving the efficiency of a DC-DC conversion circuit. As shown in FIG. 2, the method includes the following steps:

1 01. Detecting a current flowing through an inductor of the DC-DC conversion circuit for energy storage and release while turning on and off a plurality of MOSFET field effect transistors in the DC-DC conversion circuit according to a predetermined period .

In the DC-DC conversion circuit, a plurality of MOSFETs used as power MOSFETs are divided into two groups, two sets of MOSFETs are alternately turned on at a predetermined cycle, and a current flowing through an inductor for energy storage and release is also described. The predetermined period changes. In practical applications, in order to make the structure and control of the circuit simpler, a group of M0S FETs can be formed by N-channel MOSFETs, and another group of MOSFETs can be formed by P-channel MOSFETs, and the two sets of MOSFETs are alternately turned on.

The current flowing through the inductor is detected to determine whether the value of the current flowing through the inductor is lower than a preset lower current threshold. If the value of the current flowing through the inductor is not lower than the current lower threshold, the current detection is continued; if the value of the current flowing through the inductor is lower than the lower current threshold, the process proceeds to step 102. .

In practical applications, in order to measure the current flowing through the inductor coil, a detection resistor connected in series with the inductor coil may be provided, and by measuring the voltage across the sense resistor, according to the formula: current=voltage/resistance, the flow through the inductor is obtained. The value of the current of the coil.

1 02. When the current flowing through the inductor coil is lower than a preset lower current threshold, a control level is sent to a gate of a part of the plurality of M0 SFET field effect transistors, so that The partial MOSFET field effect transistor is continuously turned off. It is no longer turned on according to a predetermined period.

When the output power of the DC-DC converter circuit continues to decrease, the current flowing through the load device continues to decrease so as to be lower than the predetermined light load current value, at which time the load device enters a light load state. In the light load state, the current flowing through the inductor will be lower than the lower current threshold when periodically changing. The portion of the MOSFET is turned off by detecting the control level to the gate of the portion of the MOSFET used as the power MOSFET, in the event that the current flowing through the inductor is detected to be below the lower current threshold. Specifically, after the control level is input to the gate of the partial MOSFET, the voltage difference between the gate and the source of each of the partial MOSFETs becomes zero, so that some of the MOSFETs are turned off. status. Thereafter, the transistor controller in the DC-DC conversion circuit maintains the control level such that the portion of the MOSFET continues to be in a cut-off state due to the input of the control level, and is no longer turned on in accordance with the predetermined period.

In terms of circuit configuration, the portion of the MOSFET that is in an off state for a long time is equivalent to having been detached from the DC-DC conversion circuit. Since the number of MOSFETs is reduced in the circuit, the number of times the MOSFET is periodically turned on and off is correspondingly reduced, thereby reducing the charge and discharge loss of the gate capacitance when the MOSFET is frequently turned on and off.

After completing step 102, the method may further include step 103.

103. Stop transmitting the control level when the current flowing through the inductor is higher than a predetermined upper current threshold.

When the output power of the DC-DC converter circuit continues to rise, the current flowing through the inductor coil will be higher than the current upper threshold (the current upper threshold is greater than the current lower threshold). Stopping the delivery of the control level when detecting that the current flowing through the inductor is higher than the upper limit of the current, the gate of the portion of the MOSFET is not controlled by the control after stopping the delivery of the control level Level control, the transistor controller in the DC-DC conversion circuit can continue to conduct the on and off control of the portion of the MOSFET for the predetermined period.

For example, as shown in FIG. 3, four P-channel type MSOFETs are connected in parallel on the BUCK type DC-DC conversion circuit, respectively, M _P1 , M _P2 , M _P3 , M _P4 , and three N-channels in parallel. The channel MOSFETs are M _N1 , M _N2 , M _N3 , which are the power MOSFETs in the circuit. A transistor controller 31 is coupled to the gates of the seven MOSFETs to control the turn-on and turn-off of the MOSFET. Output voltage V. Loaded on the load device 32. Assume that the transistor controller 31 is provided with an OSC (oscillator), and the oscillation period of the 0SC is T. . In an oscillating cycle The transistor controller 31 sends the level signal to the gate of the MOSFET, and controls M _P1 , M _P2 , M _P3 , and M _{P4 to} be in an on state, and M _N1 , M _N2 , and M _N3 are in an off state; During the remaining time of the oscillation period, the transistor controller 31 turns off M _P1 , M _P2 , M _P3 , and M _P4 , and turns M _N1 , M _N2 , and M _N3 into an on state, thus performing cyclic switching. The duration of the predetermined period is T. . When the circuit is running, it can flow through the inductor L in Figure 3. The current is detected. Certainly, the predetermined period may be set by using a method other than the 0SC, which is not limited by the embodiment of the present invention. If flowing through the inductor L. The current below the lower current threshold will turn off part of the MOSFET to reduce the charge and discharge losses of the gate capacitance of the MOSFET. In FIG. 3, the transistor controller 31 flows through the inductor L through the pair. Current i. The detection of some MOSFETs gives a control level to make it off. For the MOSFET receiving the control level, it can be set in advance. For example, the setting transistor controller 31 simultaneously issues control levels to M _N1 , M _N2 , 3⁄4^ to turn off the three MOSFETs.

After turning off part of the MOSFET, the efficiency η of the BUCK type DC-DC converter circuit shown in Figure 3 will be improved. The following is a description of the formula.

Among them, P. = Volo, I. Is the current flowing through the load device 32, P. The output power of the load device 32.

Pi = I ₀ ² [R!+(1-D) R _N +DR _P ] , which is the DC loss of the entire circuit, where R _N and R _P are the conduction of the N-channel MOSFET and the P-channel MOSFET, respectively. When the resistance value, D is the turn-on time of the P-channel MOSFET at one T. The percentage occupied by (1-D) is the turn-on time of the N-channel MOSFET at one T. The percentage within is the equivalent resistance of the rest of the circuit except the MOSFET and load device 32.

P ₂ = [V _IN ² (C _N + C _P ) + KI. ] /T. , P ₂ , V _IN ² (C _N + C _P ) /T. It is the power loss caused by the charge and discharge of the gate capacitance of the MOSFET, KI. /T. It is the loss caused by the MOSFET turning on and off. Where V _IN is the input voltage and K is a parameter related to the speed at which the MOSFET is turned on and off. The values of (^ and C _P are proportional to the number of N-channel MOSFETs and P-channel MOSFETs in the circuit, respectively. The numerator and denominator on the right side of the equation ( 1 ) are divided by 1.

[ i+(lD) R _N +DR _P ] (2)

P ₂ /Io = [V _IN ² (C _N +Cp) /I ₀ +K] /T„ (3) It can be seen that due to V. It is fixed, and the size of η depends on formula (2) and formula (3). Among them, by reducing the number of power MOSFETs in the circuit, the sum of (^ is reduced, and Ρ ₂ can be lowered; in addition, the values of R _N and R _P are respectively used as N-channel MOSFETs used as power MOSFETs, P-channel type The number of MOSFETs in the circuit is inversely proportional. If the value of (^ is lower, then there will be a certain degree of increase. I. When changing, the formula (2), (3) will result in the overall value on the right side of the equal sign. When the load device 32 on the circuit is in a light load state, the value of I. is smaller, because I in the right part of the equal sign of equation (3) is at the position of the denominator, formula (3) is equal to the right The change in the overall value of the side will be more obvious than the change in the overall value on the right side of the equation (2), ie when reducing the number of power MOSFETs in the circuit, [V _IN ² (C _N + C _P ) / Io+K ] /Τ„ The reduced value is greater than I. [Ri+ (1 -D) R _N +DR _P ] The increased value. Therefore, the circuit shown in Figure 3 can increase η.

With the I of the DC-DC converter circuit. As the output power is gradually increased, the load device 32 is decoupled from the light load state when the current L is detected. Above the current upper threshold, the transistor controller 31 stops transmitting the control level to M _N1 , M _N2 , M _P1 . Thereafter, transistor controller 31 continues to T. For the period, four P-channel MOSFETs and three N-channel MOSFETs are alternately turned on and off.

In different application scenarios, the number of MOSFETs that need to receive the control level may be preset according to different requirements for efficiency η. For example, in an application scenario, it is necessary to turn off at least three MOSFETs to meet the requirement of efficiency η, and the transistor controller 31 in FIG. 3 transmits the control level to three of the seven MOSFETs to ensure that Efficiency η. In the actual operation, three MOSFETs can be randomly selected from the seven MOSFETs, which is not limited in the embodiment of the present invention.

It should also be noted that the current flowing through the inductor is measured in Figure 3. A detecting resistor connected in series with the inductor coil may be provided. By measuring the voltage across the detecting resistor, the value of the current flowing through the inductor coil is obtained according to the formula: current=voltage/resistance; The voltage of the channel type MOSFET and the P-channel type MOSFET is calculated based on the equivalent resistance of the MOSFET connected in parallel, that is, the current flowing through the MOSFET in the on state. .

The DC-DC conversion circuit described in FIG. 3 is a synchronous rectification BUCK type circuit structure which is common in practical applications, as shown in FIG. In the DC-DC conversion circuit shown in FIG. 4, J > 2) P-channel type MOSFETs are connected in parallel as a power MOSFET, and a diode D is also provided in the circuit. The transistor controller 41 controls the P-channel type MOSFET to periodically turn on and off, thereby periodically being in an on state and an off state. When the P-channel MOSFET is turned on by the transistor controller 41, the diode D is in an off state, and when the P-channel MOSFET is turned off by the transistor controller 41, the diode D is turned on. status. N-channel MOSFETs are not deployed in such circuits. In order to achieve an improvement in the efficiency of the DC-DC converter circuit, the transistor controller 41 issues a control level to a portion of the P-channel type MOSFET by detecting the current flowing through the inductor L so as to be in an off state. It is possible to reduce the charge and discharge loss of the gate capacitance of the MOSFET by having Jo (Jo<J) MOSFETs receiving the control level and being in a long-time off state, and no periodic on/off operation is performed. The efficiency of the DC-DC conversion circuit is improved.

As the current flowing through the load device 42 increases, the output power of the load device 42 gradually rises, and the transistor controller 41 stops moving toward J. Each MOSFET sends the control level, and all MOSFETs can be alternately turned on periodically.

It should be noted that, in order to measure the current i _u flowing through the inductor coil in FIG. 4, a detecting resistor connected in series with the inductor coil may be provided, and the voltage across the detecting resistor is measured according to the formula: current=voltage/resistance The value of the current flowing through the inductor coil is obtained. The voltage of the parallel P-channel MOSFET can also be measured, and the current flowing through the P-channel MOSFET in the on state, that is, the current i _u can be calculated.

The DC-DC conversion circuit may be a BUCK type circuit that converts an input DC voltage into an output DC voltage having a lower voltage value, or a BOOST type circuit that converts an input DC voltage into an output DC voltage having a higher voltage value. The BOOST type circuit can be divided into a synchronous rectification BOOST type circuit and a non-synchronous rectification BOOST type circuit. The following description will be made by taking FIG. 5 and FIG. 6 as an example.

Fig. 5 is a synchronous rectification BOOST type DC-DC conversion circuit. There are R P-channel MOSFETs connected in parallel, and S (R > 2, S > 2) N-channel MOSFETs are also connected in parallel. The transistor controller 51 alternately turns on the N-channel type MOSFET and the P-channel type MOSFET by controlling the MOSFET to be turned on and off periodically. In FIG. 5, in order to improve the efficiency of the DC-DC conversion circuit, the transistor controller 51 issues a control level to a portion of the MOSFET by detecting the current i _u flowing through the inductor L _{2 to be} turned off. . It can be assumed that there is S. (S. < R + S ) MOSFETs receive the control level In the long-term cut-off state, periodic opening and closing operations are no longer performed. For which ones to choose

The MOSFET is used as the MOSFET receiving control level, which can be set in advance. For related description, refer to the previous description of the synchronous rectification BUCK DC-DC converter circuit of Figure 3.

As the current flowing through the load device 52 increases, the output power of the load device 52 gradually rises, and the transistor controller 51 stops transmitting the control level to the portion of the MOSFET, and all of the MOSFETs can be periodically alternately turned on.

It should be noted that, in order to measure the current iu flowing through the inductor coil in FIG. 5, a detecting resistor connected in series with the inductor coil may be provided, and the voltage across the detecting resistor is measured according to the formula: current=voltage/resistance, Obtaining the value of the current flowing through the inductor coil; respectively, measuring the voltages of the parallel N-channel type MOSFET and the P-channel type MOSFET, and calculating the conduction current through the MOSFET according to the equivalent resistance of the parallel MOSFET Current, ie electricity iu.

Fig. 6 is a non-synchronous rectification BOOST type DC-DC conversion circuit. There are X ( X > 2 ) N-channel type MOSFETs connected in parallel, and a diode D _lD transistor controller 61 is arranged in the circuit to control the N-channel type MOSFET to periodically turn on and off, thereby being periodically turned on. And cutoff status. When the N-channel type MOSFET is in the on state by the control of the transistor controller 61, the diode 0 is in the off state, and when the N-channel type MOSFET is in the off state by the control of the transistor controller 61, the diode 0 _{1 is} in the conducting state. Pass state. A P-channel MOSFET is not deployed in such a circuit. In order to achieve an improvement in the efficiency of the DC-DC converter circuit, the transistor controller 61 issues a control level to a portion of the N-channel type MOSFET by detecting the current flowing through the inductor L ₃ to be in an off state. It can be assumed that there is X. (Xo<X) MOSFETs receive the control level and are in a long-term off state, no longer periodically turn on and off, thereby reducing the charge and discharge loss of the gate capacitance of the MOSFET and improving the DC-DC conversion. The efficiency of the circuit.

As the current flowing through the load device 62 increases, the output power of the load device 62 gradually rises, and the transistor controller 61 stops moving toward X. Each MOSFET sends the control level, and all MOSFETs can be alternately turned on periodically.

It should be noted that, in order to measure the current iu flowing through the inductor coil in FIG. 6, a detecting resistor connected in series with the inductor coil may be provided, and the voltage across the detecting resistor is measured according to the formula: current=voltage/resistance, The value of the current flowing through the inductor coil is obtained. The voltage of the parallel N-channel MOSFET can also be measured, and the current flowing through the P-channel MOSFET in the on state, that is, the current i _u can be calculated. Four kinds of DC-DC conversion circuits, such as synchronous rectification BUCK type, asynchronous rectification BUCK type, synchronous rectification BOO ST type, and asynchronous rectification BOOST type, can be preset according to different requirements of efficiency in different application scenarios. For the description of the number of control level M0 SFETs, refer to the foregoing description of the synchronous rectification BUCK type DC-DC conversion circuit of FIG. 3, and details are not described herein again.

In addition, the embodiment of the present invention further provides a DC-DC conversion circuit control device. As shown in FIG. 7, the device includes: a level control unit 7.1 and a current detecting unit 72.

The level control unit 7 1 is for controlling the on and off of the plurality of MOSFET field effect transistors in the DC-DC conversion circuit in accordance with a predetermined period;

The current detecting unit 72 is configured to detect, during the predetermined period of turning on and off the plurality of MOSFET FETs in the DC-DC conversion circuit, the energy storage and release flowing through the DC-DC conversion circuit. Current of the inductor coil;

The level control unit is further configured to control a gate of a portion of the MOSFET field effect transistors in the plurality of MOSFET FETs when the current flowing through the inductor is lower than a preset lower current threshold The level is such that the portion of the M0 SFET field effect transistor is continuously turned off and is no longer turned on for a predetermined period.

From the circuit configuration, the portion of the MOSFET that is in the off state for a long time is equivalent to having been detached from the DC-DC conversion circuit. Since the number of MOSFETs is reduced in the circuit, the number of times the M0 SFET is turned on and off in the predetermined period is also reduced, thereby reducing the charge and discharge loss of the gate capacitance when the MOSFET is frequently turned on and off.

Further, the level control unit 71 is further configured to stop transmitting the control level when the current flowing through the inductor coil is higher than a current upper limit threshold, so that the part of the MOSFET FET continues to follow a predetermined period Turn-on and turn-off.

After the supply of the control level is stopped, a voltage difference occurs between the gate and the source of the partial MOSFET, so that it can be turned back on. Thereafter, the transistor controller in the DC-DC conversion circuit can continue to turn on and off the portion M 0 S F E T at the predetermined period.

The device according to the embodiment of the invention can be applied to four DC-DC conversion circuits, such as a synchronous rectification BUCK type, an asynchronous rectification BUCK type, a synchronous rectification BOOST type, and an asynchronous rectification BOOST type. For details, refer to FIG. 3 above. The related description to FIG. 6 will not be repeated here.

In practical applications, as shown in FIG. 8, the sum control unit of the device and the level control unit 7 The current detecting unit 72 is integrated into the transistor controller 81 of the DC-DC converting circuit. Of course, the current detecting unit 71 and the level controlling unit 72 may also be independently disposed outside the transistor controller 81, and respectively connected to the gates of the respective MOSFETs. The device is integrated into the transistor controller 81 of the DC-DC conversion circuit, which is a preferred solution, but the embodiment of the invention does not limit this. 8 is an example of a non-synchronous rectification BUCK type DC-DC conversion circuit. Of course, it may be any one of a synchronous rectification BUCK type, a synchronous rectification BOOST type, and a non-synchronous rectification BOOST type DC-DC conversion circuit. The embodiments of the invention are not described again.

The method for improving the efficiency of a DC-DC conversion circuit and the DC-DC conversion circuit control device provided by the embodiments of the present invention, by detecting the current in the inductor coil, and when the current of the inductor coil is lower than a preset current lower limit threshold The MOSFET delivers a control point level, so that the part of the MOSFET is in an off state, which avoids the gate capacitance charge and discharge loss caused by the partial MOSFET during the periodic opening and closing operations, thereby improving the DC-DC under light load conditions. The efficiency of the conversion circuit.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general hardware, and of course, by hardware, but in many cases, the former is a better implementation. . Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a readable storage medium, such as a floppy disk of a computer. A hard disk or optical disk, etc., includes instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention.

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

Claim

What is claimed is: 1. A method of improving efficiency of a DC-DC conversion circuit, comprising: detecting and flowing through said plurality of MOSFET field effect transistors in a DC-DC conversion circuit in accordance with a predetermined period a current for an energy storage and release inductor in a DC-DC conversion circuit;

Transmitting a control level to a gate of a portion of the plurality of MOSFET field effect transistors to cause the portion of the MOSFET field effect when the current flowing through the inductor is lower than a predetermined lower current threshold The transistor is continuously turned off and is no longer turned on for a predetermined period.

2. The method according to claim 1, further comprising:

When the current flowing through the inductor coil is higher than a preset current upper threshold, the supply of the control level is stopped, so that the portion of the MO S F E T field effect transistor continues to be turned on and off according to a predetermined period.

3. Method according to claim 1 or 2, characterized in that the method can be used for BUCK type and BOOST type DC-DC conversion circuits.

A DC-DC conversion circuit control device, comprising: a level control unit for turning on and off a plurality of MOSFET field effect transistors in a DC-DC conversion circuit according to a predetermined period; control;

The level control unit is further configured to: when the current flowing through the inductor is lower than a preset current lower threshold, transmit control power to a gate of a portion of the plurality of MOSFET field effect transistors Flat, so that the portion of the MOSFET field effect transistor is continuously turned off, and is no longer turned on according to a predetermined period.

The device according to claim 4, wherein the level control unit is further configured to stop conveying the control level when a current flowing through the inductor coil is higher than a preset current upper limit threshold. So that the portion of the MO SFET field effect transistor continues to turn on and off at a predetermined period.

6. Apparatus according to claim 4 or claim 5 wherein said apparatus is operable For BUCK type and BOOST type DC-DC conversion circuits,