TWI786620B - boost control circuit - Google Patents

Abstract

The invention discloses a boost control circuit. The boost control circuit includes an inductor, a first switch connected in series with the inductor between the input terminal and the output terminal of the boost control circuit, and a second switch connected in series with the inductor between the input terminal and ground, characterized in that , further comprising: a switch controller configured to generate signals for controlling the first switch and the second switch based on the voltage feedback signal representing the output voltage of the boost control circuit and the current sampling signal representing the current flowing through the second switch The first control signal and the second control signal for turning on and turning off. According to the boost control circuit provided by the embodiment of the present invention, a switch control signal is generated by a switch controller, so as to control the on and off of the corresponding switch of the boost control circuit based on the switch control signal, and then modulate the output voltage control.

Description

boost control circuit

The invention belongs to the field of integrated circuits, in particular to a boost control circuit.

Usually, the traditional voltage regulation system is a voltage modulation control system with current feedback. The biggest feature of this traditional system is that it needs to sample the inductor current to generate current feedback and participate in the voltage and current loop control of the voltage regulation system.

However, in order to perform current sampling, it is often necessary to introduce a complex circuit structure to perform current sampling, which greatly increases the circuit area and increases the complexity of circuit design.

The embodiment of the present invention provides a boost control circuit, instead of using the traditional method of sensing and sampling the inductor current, a switch controller is used to generate a switch control signal to control the boost control circuit based on the switch control signal The corresponding switch is turned on and off, and then the output voltage is modulated and controlled.

An embodiment of the present invention provides a boost control circuit, including an inductor, a first switch connected in series with the inductor between the input end and the output end of the boost control circuit, and a first switch connected in series with the inductor between the input end and ground The second switch is characterized in that it further includes: a switch controller configured to generate, based on the voltage feedback signal representing the output voltage of the boost control circuit and the current sampling signal representing the current flowing through the second switch, respectively used to control the second switch. A first control signal and a second control signal for turning on and off the first switch and the second switch.

According to the boost control circuit provided by the embodiment of the present invention, the switch controller includes a third switch, a fourth switch, and a capacitor, and the switch controller is further configured to: generate a voltage for controlling the second switch based on the voltage feedback signal and the current sampling signal a second control signal for turning on and off the switch and the third switch; generating a first control signal for controlling the turning on and off of the first switch and the fourth switch based on the second control signal and the voltage on the capacitor; wherein , the charging of the capacitor Charging and discharging are related to the turn-on and turn-off of the third switch and the fourth switch.

According to the boost control circuit provided by an embodiment of the present invention, the switch controller is further configured to: generate a second control signal based on the first comparison result between the voltage feedback signal and the first reference signal and the current sampling signal.

According to the boost control circuit provided by an embodiment of the present invention, the switch controller is further configured to: generate a second control signal based on the first comparison result and the second comparison result between the current sampling signal and the second reference signal.

According to the boost control circuit provided by the embodiment of the present invention, the third switch and the fourth switch are connected in series between the current source and the ground, the capacitor is connected in parallel at both ends of the fourth switch, and the switch controller further includes: a first comparator The device is configured to generate a second comparison result based on the current sampling signal and the second reference signal; the flip-flop is configured to generate a second control signal based on the first comparison result and the second comparison result; and the generator is configured The first control signal is generated based on the second control signal and the voltage on the capacitor, wherein the voltage on the capacitor is the voltage on the capacitor in a discharged state.

According to the boost control circuit provided by the embodiment of the present invention, the conduction time of the second switch and the third switch is determined by the following formula:

Wherein, T _on is the turn-on time of the second switch and the third switch, Vref 2 is the second reference signal, Rsns is the resistance value of the resistor used to generate the current sampling signal, and I 0 is the moment from turning off to turning on of the second switch Corresponding to the inductor current, L is the inductance value of the inductor, and Vin is the input voltage of the boost control circuit.

According to the boost control circuit provided by the embodiment of the present invention, the conduction time of the first switch and the fourth switch is determined by the following formula:

Wherein, Toff is the conduction time of the first switch and the fourth switch, and Vout is the output voltage.

According to the boost control circuit provided by the embodiment of the present invention, the first switch, the second switch, the third switch, and the fourth switch are metal-oxide-semiconductor field-effect transistors, and And the flip-flop is an RS flip-flop.

The boost control circuit provided according to an embodiment of the present invention further includes: a second comparator configured to generate a first comparison signal based on the voltage feedback signal and the first reference signal; The voltage is divided to generate a voltage feedback signal; the first diode, the two poles of the first diode are respectively connected to the source and drain of the first switch, and the gate of the first switch receives the first control signal; and the second Two diodes, the two poles of the second diode are respectively connected to the source and the drain of the second switch, and the gate of the second switch receives the second control signal.

According to the boost control circuit provided by the embodiment of the present invention, the boost control circuit works in a continuous conduction mode or a discontinuous conduction mode.

The boost control circuit of the embodiment of the present invention no longer uses the traditional method of sensing and sampling the inductor current, but uses a switch controller to generate a switch control signal to control the corresponding voltage of the boost control circuit based on the switch control signal. The switch is turned on and off, and then the output voltage is modulated and controlled.

100,200: boost control circuit

210: switch controller

220: comparator

230: Voltage divider circuit

2101: comparator

2102: Trigger

2103: Toff generator

a: node

C1, C2, C3: Capacitors

D1, D2, D3, D4: Diodes

HG,LG:Signal

I1, I2: current

L: inductance

M1, M2, M3, M4, SW1, SW2: switch

R0, R1, R2, Rsns: resistance

T1, T2, T3: time

Ton, Toff: time

V1: valley value

V2: Peak

Vc: output signal

Vfb: voltage feedback signal

Vin: input voltage

Vout: output voltage

Vramp: ramp voltage (signal)

V_ramp1: rising ramp signal

Vref: reference signal

Vref2: reference voltage (signal)

Vsns: current sampling signal

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the diagrams that need to be used in the embodiments of the present invention will be briefly introduced below. Other schemas can be derived from these schemas.

FIG. 1 shows a schematic structural diagram of a boost control circuit 100 provided in the prior art;

FIG. 2 is a schematic structural diagram of a boost control circuit 200 provided by an embodiment of the present invention;

3 is a schematic structural diagram of a switch controller in a boost control circuit provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of waveforms of various signals in the boost control circuit in the continuous conduction mode provided by an embodiment of the present invention; and

FIG. 5 is a schematic diagram of waveforms of various signals in the boost control circuit in the discontinuous conduction mode provided by an embodiment of the present invention.

Features and exemplary implementations of various aspects of the invention are described in detail below For example, in order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It should be understood that the specific embodiments described here are only configured to explain the present invention, not to limit the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by showing examples of the present invention.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the word "comprising..." does not exclude the presence of additional same elements in the process, method, article or device comprising said element.

In order to better understand the present invention, first, the prior art is introduced, referring to FIG. 1 , which shows a schematic structural diagram of a boost control circuit 100 provided by the prior art.

In FIG. 1, the boost control circuit 100 includes an inductor L, a switch M1, a switch M2, a diode D1, a diode D2, and a capacitor C1. As shown in FIG. 1, one end of the inductor L is connected to the input of the circuit end, the other end of the inductor L is connected to one end of the switch M1, the other end of the switch M1 is connected to the output end of the circuit, and the output end is grounded via the capacitor C1, and one end of the switch M2 is connected to the common end of the inductor L and the switch M1, The other end of the switch M2 is grounded, and the switch control signals used to control the on and off of the switches M1 and M2 are HG and LG respectively, and the two poles of the diode D1 are connected to the terminal of the switch M1 except for receiving the HG signal. The two poles of the diode D2 are connected between the two terminals of the switch M2 except the terminal for receiving the LG signal.

Wherein, Vin is the input voltage of the boost control circuit 100, Vout is the output voltage of the boost control circuit 100, for the boost control circuit 100, the output voltage Vout is larger For the input voltage Vin; M1 and M2 are switches used to control the boost, for example, M1 is the output control switch, M2 is the inductance energy storage switch; L is the inductance used to control the boost; Ton is the control switch M2 conduction time, and Toff is the time when the control switch M1 is turned on.

In this traditional circuit, a current sampling circuit is added to sample the inductor current to generate a current feedback signal, and based on the current feedback signal to control the on and off of the switches M1 and M2, and then adjust The output voltage Vout is changed so that the output voltage Vout can be greater than the input voltage Vin.

However, this traditional method of sampling the inductor current through a current sampling circuit to generate current feedback, and then modulating the output voltage based on the current feedback greatly increases the circuit area and increases the complexity of the circuit design.

In order to solve the problem of the conventional technology, an embodiment of the present invention provides a boost control circuit. The boost control circuit provided by the embodiment of the present invention no longer senses and samples the inductor current, but establishes modulation control on the output voltage through the principle of volt-second balance.

It should be noted that the boost control circuit provided by the embodiment of the present invention is only an exemplary implementation manner, and the present invention is not limited thereto. For example, the principle provided by the embodiment of the present invention can also be applied to the Voltage control circuits, etc., their equivalents and configurations, etc. are within the scope of the present invention.

Continuing to refer to Figure 1, based on the principle of volt-second balance, when the output switch M2 is turned on, the change of the current flowing through the inductor can be expressed as the following formula:

It can be seen that in Equation (1), the inductor current IL is a function of Vin and T _on , as mentioned above, in the traditional structure, this inductor current is sensed and sampled, and across a resistor (for example, resistor R0) Generate a voltage (as shown in equation (2)), and then input this voltage into the loop control of the boost control circuit.

Among them, k is the coefficient of the sensed and sampled inductor current, which is a constant. Resistor R0 is a resistor used to convert current to voltage. This resistor R0 can be a resistor connected in series with inductor L, or it can be a resistor used to convert current to voltage in a current sampling circuit. Vin is the input voltage of the structure , T _on is the on-time of switch M2.

As an example, refer to FIG. 2 , which is a schematic structural diagram of a boost control circuit 200 provided by an embodiment of the present invention.

As shown in FIG. 2 , the boost control circuit 200 may include an inductor L, a switch M3, a switch M4, a diode D3, a diode D4, a capacitor C2, a switch controller 210, a comparator 220 and a voltage divider circuit 230. .

As an example, the switch controller 210 may be configured to generate The signal HG for controlling the turn-on and turn-off of the switch M3 and the signal LG for controlling the turn-on and turn-off of the switch M4 are respectively used.

Specifically, in some embodiments, the switches M3 and M4 may be MOS transistors (Metal-Oxide-Semiconductor, metal-oxide-semiconductor field-effect transistors).

As an example, one end of the inductor L can be connected to the input end of the boost control circuit 200, the other end of the inductor L can be connected to one end of the switch M3, and the other end of the switch M3 can be connected to the output end of the boost control circuit 200, Two poles of the diode D3 can be connected to both ends of the switch M3 (for example, source and drain), one end of the switch M4 can be connected to the common terminal of the inductor L and the switch M3 (for example, node a), and the other end of the switch M4 One end can be grounded through the resistor Rsns, and the two poles of the diode D4 can be connected to both ends of the switch M4 (for example, source and drain), wherein the resistor Rsns is used to sample the current flowing through the switch M4 to generate a current sampling signal ( For example, Vsns), wherein the current sampling signal Vsns is a rising ramp signal similar to V_ramp1, the switch controller 210 can be used to receive the voltage feedback signal (for example, Vfb) and the current representing the output voltage of the boost control circuit 200 Sampling a signal (eg, Vsns) to generate two switch control signals (eg, LG and HG), wherein the gate of switch M3 can receive signal HG to turn on and off based on signal HG, and the gate of switch M4 The signal LG can be received to be turned on and off based on the signal LG, so as to modulate the output voltage Vout of the boost control circuit 200 .

In some embodiments, the voltage divider circuit 230 can be used to control the boost voltage The output voltage Vout of the circuit 200 is divided to generate a voltage feedback signal (for example, Vfb). The comparator 220 can be used to receive the reference signal Vref and the voltage feedback signal (for example, Vfb). For example, the negative input terminal of the comparator 220 It can be used to receive the reference signal Vref, and the non-inverting input terminal can be used to receive the voltage feedback signal Vfb, so as to compare the two, and generate a signal Vc to output to the switch controller 210, and wherein, the voltage divider circuit 230 can be Including two resistors connected in series (for example, R1 and R2), the present invention is not limited thereto.

Through the above technical solution provided by the embodiment of the present invention, it is no longer necessary to sense and sample the inductor current, but to generate a switch control signal through the switch controller to control the on and off of the switch, and then modulate the output voltage. On the premise of ensuring conversion efficiency, a very small boost circuit is realized, and less resources are used to realize voltage regulation, so as to be suitable for applications with limited resources.

As an example, refer to FIG. 3 , which is a schematic structural diagram of a switch controller in a boost control circuit provided by an embodiment of the present invention.

In the embodiment shown in FIG. 3 , the switch controller 210 may include switches SW1 and SW2 and a capacitor C3, and the switch controller 210 may be configured to generate a voltage for controlling the switch SW1 based on the voltage feedback signal Vfb and the current sampling signal Vsns. and the turn-on and turn-off control signal LG of M4 (see Figure 2), and then generate the control signal HG for controlling the turn-on and turn-off of switches SW2 and M3 (see Figure 2) based on the signal LG and the voltage on the capacitor C3 , and the capacitor C3 is charged when the switch SW1 is turned on and the switch SW2 is turned off, and is discharged when the switch SW1 is turned off and the switch SW2 is turned on. In some embodiments, switches SW1 and SW2 may be MOS transistors.

The following will be described in detail by way of example. Specifically, as shown in FIG. RS flip-flop.

As an example, the two input terminals of the comparator 2101 can receive the current sampling signal Vsns and the reference voltage Vref2, for example, the negative input terminal of the comparator 2101 can be used to receive the reference voltage Vref2, and the positive input terminal can be used to receive the current The sampling signal Vsns is used to compare the two, and the output terminal of the comparator 2101 can be connected to, for example, an RS flip-flop 2102 The reset terminal (marked as R), the output terminal of the comparator 220 (see FIG. 2 ) can be connected to the set element terminal (marked as S) of the RS flip-flop 2102, and the output terminal of the RS flip-flop 2102 can be connected to the switch SW1 One end (for example, gate) of the switch SW1 is controlled to be turned on and off, the switch SW1 and the switch SW2 are connected in series between the current source (marked as I1) and the ground, and the capacitor C3 is connected in parallel across the switch SW2, The output terminal of the RS flip-flop can also be connected to one input terminal of the Toff generator, and the other input terminal of the Toff generator can be connected to the common terminal of the switch SW1 and the switch SW2 to receive the voltage on the capacitor C3 in the discharge state, Toff The output terminal of the generator can be connected to one terminal (eg, gate) of the switch SW2 to control the switch SW2 to be turned on and off.

Specifically, the comparator 2101 can be configured to receive the current sampling signal Vsns and the reference signal Vref2 (used to determine whether the current sampling signal Vsns rises to the reference signal Vref2), to compare the two, and output the comparison result to the RS trigger RS flip-flop 2102, RS flip-flop 2102 also receives the comparison result Vc from the comparator 220 (see FIG. 2), so as to output the control signal LG to the switches SW1 and M4 based on the two comparison results to control the conduction and switching of the switches SW1 and M4. Turn off, that is, Ton is the conduction time of SW1 and M4. When the signal LG controls the switch SW1 to be turned on, the current source (for example, I1, the current size that the current source can provide is Vin/R1) charges the capacitor C3. A rising ramp voltage is generated on the capacitor C3 (this will be described in detail below), and the switch SW2 is turned on (or turned on after a predetermined time period, the present invention is not limited to this) at the moment when SW1 is switched from on to off. When the capacitor C3 is discharged, a falling ramp voltage (this will be described in detail below) is generated on the capacitor C3. The rising and falling ramp voltages are marked as Vramp in FIG. 3, and the Toff generator 2103 can be configured to be based on The signal LG and the voltage on the capacitor C3 in the discharge state (ie, the falling ramp voltage) generate the signal HG, and then control the switch SW2 to be turned on and off based on the signal HG.

To sum up, the Ton is determined by the time when the sampling current flowing through the switch M4 reaches the reference current, and the formula of Ton is as follows:

Wherein, T _on is the turn-on time of the switches SW1 and M4, Vref 2 is the reference signal, Rsns is the resistance value of the resistor used to generate the current sampling signal Vsns, I 0 is the inductor current corresponding to the moment when the switch M4 is turned off, For the discontinuous conduction mode (Discontinuous Conduction Mode, DCM), I 0 is 0, L is the inductance value of the inductor, and Vin is the input voltage of the boost control circuit.

Since the inductance L, the input voltage Vin and the time Ton are all known, in the circuit provided by the embodiment of the present invention, a similar current is generated and has the same functional relationship to the input Vin and the time Ton as formula (1), The inductor current can be characterized. Wherein, when the switch SW1 is turned on and the switch SW2 is turned off, the capacitor C3 is in the charging state, and the current I1 generates a rising slope voltage on the capacitor C3, and the maintenance time of the slope voltage is Ton, and the slope on the capacitor C3 in the charging state Voltage can be expressed as:

。只要選擇

，V _ramp2就可以完全代表V _ramp1。 here,

. just choose

, V _{ramp 2} can completely represent V _{ramp 1} .

Similarly, according to the principle of volt-second balance, in Figure 1, when the switch M2 is turned off and the switch M1 is turned on, the following formula is satisfied:

Based on this principle, in the embodiment shown in Figure 3, when the switch SW1 is turned off and the switch SW2 is turned on, the current I2 starts to discharge the capacitor C3 for a discharge time of Toff, during the discharge phase, the voltage on the capacitor C3 is linear A falling ramp voltage is generated on the capacitor C3, and the pulse width of the switch SW2 is turned on is Toff. It should be noted that the implementation of the circuit is not limited to the embodiments provided by the present invention, and those skilled in the art can design the circuit based on the volt-second balance principle described above without departing from the spirit and scope of the present invention. other implementations. Selecting I2 as the following formula can satisfy the volt-second balance reflected by formula (5).

Referring to FIG. 3 and FIG. 4 , FIG. 4 is a schematic waveform diagram of various signals in the boost control circuit in continuous conduction mode provided by an embodiment of the present invention. Among them, Figure 4(a) shows A schematic diagram of the curve showing the relationship between the voltage Vramp on the capacitor shown in Figure 3 and time; Figure 4 (b) shows a schematic diagram of the curve showing the relationship between the signal LG and time shown in Figure 3; and 4(c) shows a schematic diagram of the relationship between the signal HG and time shown in FIG. 3 .

As an example, when the switch SW1 is turned on and the switch SW2 is turned off, the current I1 starts to charge the capacitor C3 for a charging time of Ton (corresponding to the time period T0-T1 in FIG. 4 ). During the time period T0-T1, The voltage Vramp on the capacitor C3 rises linearly (for example, during the time period T0-T1, the voltage Vramp rises linearly from V1 (bottom) to V2 (peak), see formula (4)), and the signal LG is at a high level, and the signal HG is at a low level; and when the switch SW1 is turned off and the switch SW2 is turned on, the current I2 starts to discharge the capacitor C3, and the discharge time is Toff (corresponding to the time period T1-T2). During the time period T1-T2, the capacitor C3 The voltage on (ie, Vramp) decreases linearly (for example, during the time period T1-T2, the signal Vramp decreases linearly from V2 (peak value) to V1 (valley), see formula (6)), and the signal LG is at a low level, And the signal HG is at a high level.

Referring to FIG. 3 and FIG. 4 , in FIG. 3 a Toff generator is used to characterize the generation of the control signal HG of the switch SW2 . Wherein, the rising edge of the signal HG can be generated by the falling edge of the signal LG (for example, at time T1, the signal LG is switched from a high level to a low level, so that the signal HG is switched from a low level to a high level, see FIG. 4 ), and the signal The falling edge of HG is generated when the signal Vramp falls from the peak value V2 to the valley value V1 (for example, at time T2, when the signal Vramp falls to the valley value V1, the signal HG switches from a high level to a low level, see FIG. 4 ).

The discharge current of the capacitor C3 is selected according to formula (6), and the time taken for the signal Vramp to drop from the peak value V2 to the valley value V1 is the time Toff required to achieve volt-second balance.

In this way, the current relationship of the inductor current reflected by the formula (5) when the switches M3 and M4 are boosted under the volt-second balance can be converted into the voltage relationship shown in the formula (7):

so,

Therefore, the input voltage Vin , the output voltage Vout , and the on-time Ton of switches SW1 and M4 (see formula (3)) are all known parameters, and the on-time Toff of switches SW2 and M3 is set based on formula (8). During a time period (eg, from time T1 to time T2 in FIG. 4 ), switches M3 and SW2 are turned on.

As an example, the working principle of the boost control circuit provided by the embodiment of the present invention is introduced with reference to FIG. 2 . When the voltage feedback signal Vfb is smaller than the reference signal Vref, the output signal Vc of the comparator 220 is reversed, and its rising edge can turn on the switch. Switch SW1 in controller 210 (see FIG. 3 ). Then, the output signal Vc of the comparator 220 is reset. After the on-time Ton elapses, the switch SW1 is turned off, that is, the switch SW1 remains in the on-state during the on-time Ton. In some embodiments, after the moment when the switch SW1 is turned off, the switch SW2 can be turned on at intervals of, for example, tens of nanoseconds (can be selected according to requirements), so that the switch SW2 is turned off after the on-time Toff, that is The switch SW2 is kept in an on-state during the on-time Toff. In some other embodiments, the interval time can be zero, that is, the switch SW2 can be turned on immediately when the switch SW1 is turned off, so that the switch SW2 can be turned off after the on-time Toff, that is, the switch SW2 can be turned off during the on-time It remains on during Toff.

When the switch SW2 is turned off, the output of the comparator 220 is enabled. If the output signal Vc of the comparator 220 reverses a rising edge, the above-mentioned operation of the next cycle starts immediately. At this time, the boost control circuit works in continuous conduction mode (Constant Current Mode, CCM), as shown in Figure 4. Otherwise, wait until the output signal Vc of the comparator 220 flips to a rising edge, and then start the above operation of the next cycle. At this time, the boost control circuit works in a discontinuous conduction mode (Discontinuous Conduction Mode, DCM), as shown in FIG. 5 As shown, FIG. 5 is a schematic waveform diagram of various signals in the boost control circuit in the discontinuous conduction mode provided by the embodiment of the present invention, wherein the time period (T3-T2) represents the above-mentioned waiting time.

To sum up, the boost control circuit provided by the embodiment of the present invention no longer uses the traditional method of sensing and sampling the inductor current, but establishes the boost adjustment control of the output voltage based on the principle of volt-second balance. The purpose of this circuit is to realize a boost circuit with a small area under the premise of ensuring conversion efficiency, that is, to use the smallest resources to realize the modulation of the output voltage, and then use in resource-constrained applications.

The boost control circuit provided by the embodiment of the present invention uses a general constant on time (constant on time) structure, and the modulation control of the output switch is realized based on the principle of volt-second balance, and the change of the inductor current is replaced by RC conversion. It can be seen that the on-time of the output switch of the boost control circuit is determined by the constant on-time and RC conversion substitution.

It is to be understood that the invention is not limited to the specific arrangements and processes described above and shown in the drawings. For conciseness, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the sequence of steps after understanding the spirit of the present invention.

The functional blocks shown in the structural block diagrams above can be realized as hardware, software, firmware or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an Application Specific Integrated Circuit (ASIC), appropriate firmware, a plug-in program, a function card, and the like. When implemented in software, the elements of the invention are the programs or code segments used to perform the required tasks. Programs or code segments may be stored on a machine-readable medium or transmitted over a transmission medium or communication link by a data signal carried in a carrier wave. "Machine-readable medium" may include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, Read Only Memory (ROM), flash memory, erasable ROM (Erasable Read Only Memory, EROM), floppy disks, CD-ROMs, etc. Read memory (Compact Disc Read-Only Memory, CD-ROM), optical disk, hard disk, optical fiber media, radio frequency (Radio Frequency, RF) link, etc. Code snippets may be downloaded via computer networks such as the Internet, Intranet, and the like.

It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps, that is to say, the steps may be executed sequentially as mentioned in the embodiment, or may be different from the order in the embodiment, or several steps may be executed simultaneously.

The above is only a specific implementation of the present invention, and those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the system, modules and units described above can be implemented by referring to the aforementioned method The corresponding process in the example will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be covered in within the protection scope of the present invention.

200: boost control circuit

210: switch controller

220: comparator

230: Voltage divider circuit

a: node

C2: Capacitor

D3, D4: Diodes

HG,LG:Signal

L: inductance

M3, M4: switch

R1, R2, Rsns: resistance

Vc: output signal

Vfb: voltage feedback signal

Vin: input voltage

Vout: output voltage

Vref: reference signal

Vsns: current sampling signal

Claims (9)

A boost control circuit, comprising an inductor, a first switch connected in series with the inductor between the input end and the output end of the boost control circuit, and a first switch connected in series with the inductor between the input end and ground The second switch among them is characterized in that it further includes: a switch controller, including a third switch, a fourth switch, and a capacitor, configured to characterize the output voltage of the boost control circuit based on a voltage feedback signal and a characterization current A current sampling signal of the current passing through the second switch, generating a first control signal and a second control signal for respectively controlling the on and off of the first switch and the second switch, and, based on the a voltage feedback signal and the current sampling signal to generate the second control signal for controlling the turn-on and turn-off of the second switch and the third switch; and based on the second control signal and the capacitor to generate the first control signal for controlling the on and off of the first switch and the fourth switch; and the charging and discharging of the capacitor is related to the third switch and the The turn-on and turn-off of the four switches are related. The boost control circuit according to claim 1, wherein the switch controller is further configured to: based on the first comparison result between the voltage feedback signal and the first reference signal and the current sampling signal, generate the second control signal. The boost control circuit according to claim 2, wherein the switch controller is further configured to: based on the first comparison result and a second comparison result between the current sampling signal and a second reference signal, generating the second control signal. The boost control circuit according to claim 3, wherein the third switch and the fourth switch are connected in series between the current source and ground, and the capacitor is connected in parallel to both ends of the fourth switch, And the switch controller further includes: a first comparator configured to generate the second comparison result based on the current sampling signal and the second reference signal; a flip-flop configured to generate the second comparison result based on the first comparison result and the second comparison result, generating the second control signal; and a generator configured to generate the first control signal based on the second control signal and a voltage on the capacitor, wherein the voltage on the capacitor is the capacitor in a discharged state on the voltage. The boost control circuit according to claim 4, wherein the conduction time of the second switch and the third switch is determined by the following formula:

Wherein, T _on is the conduction time of the second switch and the third switch, Vref 2 is the second reference signal, Rsns is the resistance value of the resistor used to generate the current sampling signal, I 0 is the The inductor current corresponding to the moment from turning off to turning on of the second switch, L is the inductance value of the inductor, and Vin is the input voltage of the boost control circuit. The boost control circuit according to claim 4, wherein the conduction time of the first switch and the fourth switch is determined by the following formula:

Wherein, Toff is the conduction time of the first switch and the fourth switch, and Vout is the output voltage. The boost control circuit according to claim 4, wherein the first switch, the second switch, the third switch, and the fourth switch are metal-oxide-semiconductor field-effect transistors, and The flip-flop is an RS flip-flop. The boost control circuit according to claim 7, further comprising: a second comparator configured to generate the first comparison signal based on the voltage feedback signal and the first reference signal; circuit, configured to generate the voltage feedback signal by dividing the output voltage; the first diode, the two poles of the first diode are respectively connected to the source and drain of the first switch Pole, the gate of the first switch receives the first control signal; and a second diode, the two poles of the second diode are respectively connected to the source of the second switch and a drain, the gate of the second switch receives the second control signal. The boost control circuit according to claim 1, wherein the boost control circuit operates in a continuous conduction mode or a discontinuous conduction mode.

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