CN115411940A - Load current tracking voltage converter mode switching circuit and method - Google Patents
Load current tracking voltage converter mode switching circuit and method Download PDFInfo
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- CN115411940A CN115411940A CN202210969159.9A CN202210969159A CN115411940A CN 115411940 A CN115411940 A CN 115411940A CN 202210969159 A CN202210969159 A CN 202210969159A CN 115411940 A CN115411940 A CN 115411940A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1582—Buck-boost converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
Abstract
A voltage converter mode switching circuit and method for tracking load current is characterized in that: the circuit comprises a mode control unit and an adjusting unit; the mode control unit is used for generating a mode control signal and controlling the voltage converter to switch between a boosting mode and a voltage reduction mode based on the mode control signal; and the adjusting unit is connected with the mode control unit and used for acquiring an output signal of an error comparator in the voltage converter and generating a feedback current so as to adjust the turnover level of the mode control signal in the mode control unit. The invention has smart concept and reasonable and effective method, fully considers various different load environments of the voltage converter and fully ensures the stability of the output voltage under different environments.
Description
Technical Field
The present invention relates to the field of integrated circuits, and more particularly, to a mode switching circuit and method for a voltage converter tracking load current.
Background
A DC-to-DC voltage converter (DC-to-DC converter) is a commonly used electric energy conversion circuit, which can convert a DC power supply into a DC voltage with different voltages or a stable voltage similar to the DC voltage for output. It is widely used in various fields due to its good characteristics such as large power range and stable output voltage.
In the prior art, in order to provide a stable output voltage for a subsequent load under different power input conditions, a mainstream dc-dc voltage converter can work in different Step-up or Step-down modes, and the output voltage is adjusted by reasonably adjusting the on-off state of a power tube. Generally, the circuit structure such as the mode control unit can determine the operation mode of the voltage converter according to the magnitude of the input voltage, and realize reasonable switching between the voltage boost mode and the voltage buck mode. Therefore, the design of the flip level of the mode control signal plays a crucial role in determining whether the operation performance of the voltage converter is reasonable.
However, in the current voltage converter circuit, since the voltage converter may operate in a plurality of different environments such as no-load, light-load, heavy-load, and the like, it is difficult to keep the voltage converter in a reasonable mode switching in the pre-calculated flip level in each of the different environments. This causes, for example, in a light load or no-load state, the voltage converter to switch to the boost mode in advance, which causes unnecessary waste of power and a large impact on the light load circuit, and even makes it difficult to ensure the safety of the subsequent circuit.
In view of the above problems, a mode switching circuit and a mode switching method for a voltage converter are needed.
Disclosure of Invention
In order to solve the disadvantages of the prior art, an object of the present invention is to provide a load current tracking voltage converter mode switching circuit and method, which can ensure that the voltage converter can maintain reasonable operation mode switching in different load environments by approximating the magnitude of the inversion level of the linear adjustment mode control signal along with the magnitude of the load current.
The invention adopts the following technical scheme.
In a first aspect, the invention relates to a load current tracking voltage converter mode switching circuit, which comprises a mode control unit and a regulating unit; a mode control unit for generating a mode control signal and controlling the voltage converter to switch between a boost mode and a buck mode based on the mode control signal; and the adjusting unit is connected with the mode control unit and used for acquiring the output signal of the error comparator in the voltage converter and generating a feedback current so as to adjust the turnover level of the mode control signal in the mode control unit.
Preferably, the mode control unit comprises a first current source, a second current source, a first voltage-dividing resistor, a second voltage-dividing resistor, a current switching tube and an operational amplifier; the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series and then are connected between the input current Vin and the ground; the first current source I0 is connected in parallel at two ends of the second voltage-dividing resistor R2, one end of the second current source I1 is connected with the high-voltage end of the second voltage-dividing resistor R2, and the other end is connected with the drain electrode of the current switching tube; the source electrode of the current switching tube is grounded, and the grid electrode of the current switching tube is connected with the output end of the operational amplifier; the positive phase input end of the operational amplifier is connected with a reference voltage Vref, the negative phase input end of the operational amplifier is connected with a connection point between the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 to receive the resistor voltage-dividing V-, and the output end of the operational amplifier outputs a mode control signal.
Preferably, the adjusting unit comprises a reference subunit, a comparison subunit and a mirror subunit; the reference subunit is used for receiving an input voltage Vin to generate a comparison reference voltage Vref1 and inputting the comparison reference voltage Vref1 into the comparison subunit; the comparison subunit is connected with the reference subunit and the mirror subunit and used for receiving the comparison reference voltage and the output signal of the error comparator and generating a third current based on the comparison result of the comparison voltage and the output signal of the error comparator; and the mirror subunit is connected with the mode control unit and is used for mirroring the third current to the mode control unit.
Preferably, the reference subunit includes a reference tube Mp1 and a reference current source Iref; the source electrode of the reference tube Mp1 is connected with a power supply voltage, and the drain electrode and the grid electrode are grounded through a reference current source Iref; the drain and the gate of the reference tube Mp1 serve as the output of the reference subunit, and provide a comparison reference voltage Vref1 for the comparison subunit.
Preferably, the comparison subunit comprises a first input tube, a second input tube, a current mirror and a cross-over resistor; the current mirror comprises MOS (metal oxide semiconductor) tubes in mirror image connection and two identical mirror image current sources; the drain electrodes of the first input tube and the second input tube are respectively connected to the drain electrodes of the two MOS tubes, and the drain electrodes of the first input tube and the second input tube are respectively connected to the two mirror current sources; the grid of the first input tube is connected to a comparison reference voltage Vref1, and the grid of the second input tube is connected to an output signal of the error comparator; the bridging resistor is connected between the source electrode of the first input tube and the source electrode of the second input tube, and the drain electrode of the first input tube is used as the output of the comparison subunit and is connected with the mirror image subunit.
Preferably, the output end of the mirror subunit is electrically connected with the connection of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 in the mode control unit.
Preferably, the feedback current is
Wherein k is the current mirror ratio of the mirror subunit,
V EAOUT is the output voltage of the error comparator and,
and R is a bridging resistor.
Preferably, when the input voltage Vin gradually decreases, the inversion level of the mode control signal in the mode control unit is
When the input voltage Vin gradually rises, the inversion level of the mode control signal in the mode control unit is
Preferably, the inversion level V of the mode control signal in the mode control unit in L And V in H Is in linear relation with the load current of the voltage converter; the lighter the rear stage load of the voltage converter is, the more the level V is reversed in L And V in H The smaller the value of (a).
In a second aspect of the present invention, a method for switching a mode of a voltage converter tracking a load current includes the circuit for switching a mode of a voltage converter tracking a load current according to the first aspect of the present invention.
Compared with the prior art, the load current tracking voltage converter mode switching circuit and the load current tracking voltage converter mode switching method have the advantages that the size of the inversion level of the linear adjustment mode control signal can be approximated along with the size of the load current, and reasonable work mode switching of the voltage converter in different load environments is guaranteed. The invention has smart concept and reasonable and effective method, fully considers various different load environments of the voltage converter and fully ensures the stability of the output voltage under different environments.
The beneficial effects of the invention also include:
1. the invention fully utilizes related circuits such as an error amplifier and the like generally possessed by a voltage converter circuit in the prior art, realizes the calculation between the output voltage of the error amplifier and the comparison reference voltage with little cost, and generates reasonable compensation current.
2. The invention considers the linear correlation between the output voltage of the error amplifier and the load current, and ensures that the inversion level of the mode control signal can generate approximately linear change along with the change of the load current by adjusting the negative phase input voltage in the mode control unit. Therefore, no matter what load environment the voltage converter is in, the inversion level of the mode control signal can be well matched with the state of the voltage converter, and the working mode switching time of the voltage converter is reasonable and accurate.
Drawings
FIG. 1 is a schematic diagram of an equivalent circuit of a voltage converter operating in a boost mode according to the prior art;
FIG. 2 is a schematic diagram of an equivalent circuit of a voltage converter in the prior art when the voltage converter operates in a buck mode;
FIG. 3 is a schematic circuit diagram of a mode control unit of a voltage converter according to the prior art;
FIG. 4 is a circuit diagram of a load current tracking mode switching circuit of a voltage converter according to the present invention;
fig. 5 is a schematic diagram of a load current tracking voltage converter mode switching circuit in which the switching level varies linearly with the load current according to the present invention.
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present application is not limited thereby.
Fig. 1 is a schematic diagram of an equivalent circuit of a voltage converter operating in a boost mode in the prior art. As shown in fig. 1, when the voltage converter operates in the boost mode, the switches SW1 and SW2 are turned on at the same time, and the switches SW3 and SW4 are turned on at the same time, and the four switches are turned on and off alternately under the control of the related control unit, so that the output of the output voltage Vout is realized in a charge pump manner by the charge-discharge delay of the capacitor, and the voltage of Vout is higher than the input voltage Vin.
Fig. 2 is a schematic diagram of an equivalent circuit of a voltage converter in the prior art when the voltage converter operates in a buck mode. As shown in fig. 2, when the operation mode of the voltage converter is the buck mode, the switches SW2 and SW3 are in the off state, and the switches SW1 and SW4 are in the long on state, the output voltage is slightly lower than the input voltage, and the difference between the output voltage and the input voltage is determined by the magnitude of the load current. In this case, the voltage converter is equivalent to a low dropout regulator.
Fig. 3 is a schematic circuit diagram of a mode control unit of a voltage converter in the prior art. As shown in fig. 3, when the voltage converter switches between the step-up and step-down operation modes in the prior art, there is a corresponding control circuit, and the known circuit can implement the high-low level switching of the mode flag signal according to the input voltage division, i.e. the high-low level of V-in fig. 3, thereby implementing the switching of the operation modes.
In the prior art, considering the problems that the input voltage can shake back and forth near the turning point and the output of the comparator can also turn back and forth, when the power supply voltage is gradually increased and decreased, the turning level of the Modiflag signal is not completely consistent in design, so that the output of the circuit generates hysteresis, and the disturbance resistance of the system is enhanced.
In such a circuit in fig. 3, the circuit can be switched at two different levels with the series switch of the current source I1 being switched on or off.
Specifically, when I1 is not supplying current to the circuit, the inversion of Modiflag requires Vref to be equal to V-, so the equation is set forth as
Will V - ＝V ref When substituted into the formula, then have
For solving this formula, then there are
On the other hand, if I1 supplies current to the circuit, the same can be obtained
Since in this circuit, if the input voltage is gradually decreased, thereby causing the inversion of the Modeflag signal, I1 does not supply current to the circuit at this time. Conversely, if the input voltage is gradually increased, I1 will provide current to the circuit.
It can be seen that for this circuit, there are two different sized upset levels, which are high if Vin is lowered from high
Whereas if Vin is raised from low, the flip level is
However, certain problems still exist in this circuit. For example, when the voltage converters respectively operate in different load environments, it is difficult to select a reasonable magnitude of the flipping level. This is because when the circuit is operating in buck mode, the magnitude of the output voltage is not only determined by the input voltage Vin, but also takes into account the load current. At this time, the value of the output voltage is V out ＝V in -I load ·R on . In this formula, I load Is a load current, and R on Is the equivalent resistance of the power tube, i.e. the equivalent resistance of the power tube when the SW1 and the SW4 are in the normal on state in fig. 1.
It can be seen that when the parameters of the power tube are determined, the load current I load Will affect the value of the output voltage. If the circuit is operated in a light load mode, the load current I load And is very small, so Vout drops relatively little with respect to Vin. At this time, if the inversion level of the Modeflag signal, that is, vref is higher than the input voltage Vin, when the input voltage Vin is lowered, the circuit enters the boost mode earlier, and the buck mode cannot be maintained and the output of the low dropout linear regulated voltage is realized when Vin is still higher. On the other hand, if the circuit is operated in the heavy load mode, the load current is very large, and the voltage drop of Vout relative to Vin is large at this time. If the inversion level of the Modeflag signal is designed to be low, when the inversion occurs, the input voltage Vin is still small, which may cause the output voltage Vout to be difficult to meet the design requirement, and the output voltage is too low to realize normal and stable power supply for the subsequent load.
While the above description is directed to the case where the input voltage Vin gradually decreases, the circuit also needs another mode flag's toggle level to effect the transition between the boost and buck modes when the input voltage gradually increases. Similarly, if the flip level is designed to be higher in the light load state, the circuit will enter the buck mode later, resulting in a lower efficiency circuit. If the flip level is designed to be low in a heavy load state, the circuit also has the problem of too low output voltage.
Fig. 4 is a circuit diagram of a mode switching circuit of a voltage converter tracking load current according to the present invention. In view of the problems in the prior art, as shown in fig. 4, in a first aspect of the present invention, there is provided a voltage converter mode switching circuit tracking a load current, the circuit including a mode control unit and a regulation unit; the mode control unit is used for generating a mode control signal and controlling the voltage converter to switch between a boosting mode and a voltage reduction mode based on the mode control signal; and the adjusting unit is connected with the mode control unit and used for acquiring the output signal of the error comparator in the voltage converter and generating a feedback current so as to adjust the turnover level of the mode control signal in the mode control unit.
It will be appreciated that corresponding mode control units are typically present in the prior art. The newly added adjusting unit can adjust the magnitude of the feedback current and inject the feedback current into the original mode switching circuit, so that the inversion level of the control signal in the mode switching circuit is changed to a certain extent. Since the magnitude of the feedback current in the present invention is related to the output of the error comparator in the voltage converter, the level of the flip-flop is also actually dynamically adjusted with the output of the error amplifier.
The error amplifier, which is a common element in the voltage converter circuit, can determine the output voltage of the voltage converter according to a preset reference voltage and output a signal directly related to the magnitude of the load current.
Therefore, the method of the invention realizes the control of the turnover level according to the load current of the next-stage load, thereby solving the contradiction existing in the selection of the turnover level under different states of light load, heavy load, no load and the like to a certain extent.
Preferably, the mode control unit comprises a first current source, a second current source, a first voltage-dividing resistor, a second voltage-dividing resistor, a current switching tube and an operational amplifier; the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series and then connected between the input current Vin and the ground; the first current source I0 is connected in parallel at two ends of the second voltage-dividing resistor R2, one end of the second current source I1 is connected with the high-voltage end of the second voltage-dividing resistor R2, and the other end is connected with the drain electrode of the current switching tube; the source electrode of the current switching tube is grounded, and the grid electrode of the current switching tube is connected with the output end of the operational amplifier; the positive phase input end of the operational amplifier is connected with a reference voltage Vref, and the negative phase input end of the operational amplifier is connected with a connection point between the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 to receive the voltage-divided V-by the resistors, and the output end of the operational amplifier outputs a mode control signal.
It is understood that the mode control unit in the present invention is similar to the mode control unit in the prior art. Due to the addition of the current sources I0 and I1, the divided voltage V-of the input voltage Vin can be lowered even lower from different degrees, respectively. Therefore, the magnitude of the inversion level is different when the input voltage varies from different directions. And the turning level Modeflag can control the state of a power tube on the voltage converter, so that when Vin is higher than the turning level, the circuit works in a voltage reduction mode, and when Vin is lower than the turning level, the circuit works in a voltage boosting mode.
Preferably, the adjusting unit comprises a reference subunit, a comparison subunit and a mirror subunit; the reference subunit is used for receiving an input voltage Vin to generate a comparison reference voltage Vref1 and inputting the comparison reference voltage Vref1 into the comparison subunit; the comparison subunit is connected with the reference subunit and the mirror subunit and used for receiving the comparison reference voltage and the output signal of the error comparator and generating a third current based on the comparison result of the comparison voltage and the output signal of the error comparator; and the mirror image subunit is connected with the mode control unit and is used for mirroring the third current to the mode control unit.
It will be appreciated that the regulating unit may be formed of three basic circuit configurations, wherein the reference sub-unit is capable of outputting a reference voltage, which is thus supplied to the comparison sub-unit for comparison. The comparing subunit is also capable of receiving the output signal of the error amplifier, i.e. EAOUT in fig. 4, and comparing the two signals to obtain a differential current. The differential current is output in a certain proportion through the mirror image subunit, and further adjustment of the V-voltage is achieved.
Preferably, the reference subunit comprises a reference tube Mp1 and a reference current source Iref; the source electrode of the reference tube Mp1 is connected with a power supply voltage, and the drain electrode and the grid electrode are grounded through a reference current source Iref; the drain and the gate of the reference tube Mp1 serve as the output of the reference subunit, and provide a comparison reference voltage Vref1 for the comparison subunit.
It is understood that the reference subunit of the present invention can set the reference current source Iref to a very small current source, for example, only 2 μ a of current is output. Meanwhile, the size of the Mp1 tube is also very small, for example, the size or the number of the Mp1 tubes can be designed to be 1/1500 of the size of the power tube. In this case, the branch formed by the reference subunit does not have too much influence on the power transistor, and the power consumption of the secondary structure in the chip is saved. In such a circuit configuration, the magnitude of the comparison reference voltage Vref1 may be actually variable, for example, may vary with the magnitude of the input voltage Vin. However, since the output of the error amplifier is not only affected by the load current, but also affected by the input voltage Vin, and the current ratio between Vref1 and EAOUT is fixed due to the power tube and Mp1, the comparison between Vref1 and EAOUT only takes into account the change of the load current.
In the above-mentioned embodiment, if Iref is 2 μ a and Mp1 is 1/1500 of the power transistor, vref1 can always be consistent with the output of the error amplifier when the load current is 3mA, regardless of the variation of the input voltage Vin. Therefore, the circuit can accurately judge the state of the load current at the moment, for example, when the load current is greater than 3mA, the corresponding feedback current output exists in the circuit, and if the load current is equal to or less than 3mA, the circuit does not output any feedback current. This function is embodied by the comparison subunit.
Preferably, the comparison subunit comprises a first input tube, a second input tube, a current mirror and a cross-over resistor; the current mirror comprises MOS (metal oxide semiconductor) tubes in mirror image connection and two identical mirror image current sources; the drain electrodes of the first input tube and the second input tube are respectively connected to the drain electrodes of the two MOS tubes, and the drain electrodes of the first input tube and the second input tube are respectively connected to the two mirror current sources; the grid of the first input tube is connected to a comparison reference voltage Vref1, and the grid of the second input tube is connected to an output signal of the error comparator; the bridging resistor is connected between the source electrode of the first input tube and the source electrode of the second input tube, and the drain electrode of the first input tube is used as the output of the comparison subunit and is connected with the mirror image subunit.
It is understood that the comparison subunit of the present invention can implement the comparison between Vref1 and EAOUT. When the EAOUT is smaller than Vref1, the drain-source current of the first input tube is larger than that of the second input tube, so that no current output exists at the output end of the comparison subunit. And when Vref1 is smaller than EAOUT, the drain-source current on the first input tube is smaller than the drain-source current on the second input tube, and the redundant current generated by the MOS tube connected by the mirror image is output from the output end of the comparison subunit. In particular, the magnitude of this current should be such that
Preferably, the output end of the mirror subunit is electrically connected with the connection of the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 in the mode control unit.
In the mirror image subunit, there are several mirror image MOS transistors to mirror the output of the comparison subunit in certain proportion, and this proportion coefficient is k.
Preferably, the feedback current is
Wherein k is the current mirror ratio of the mirror subunit,
V EAOUT is the output voltage of the error comparator and,
and R is a bridging resistor.
In this case, a calculation formula of the feedback current can be determined. It can be seen that if EAOUT is too small, i.e. the load current is large, the value of I2 will increase with the increase of the load current.
Preferably, the inversion level V of the mode control signal in the mode control unit in L And V in H Is in linear relation with the load current of the voltage converter; the lighter the rear stage load of the voltage converter is, the more the level V is reversed in L And V in H The smaller the value of (a).
FIG. 5 is a diagram illustrating a linear variation of the flip level with the load current in the load current tracking mode switch circuit of the voltage converter according to the present invention. As shown in fig. 5, it can be understood that, as the load current changes, the value of I2 also changes, and the change is approximately linear when the power tube operates in the saturation region. In addition, since the level V is reversed in L And V in H The values of I2 are also linear, so that the inversion level V can be deduced in L And V in H Is linear with the load current of the voltage converter.
Preferably, when the input voltage Vin gradually decreases, the inversion level of the mode control signal in the mode control unit is
When the input voltage Vin gradually rises, the inversion level of the mode control signal in the mode control unit is
It can be understood that the switching level is further changed after the feedback current is added, however, since the magnitude of I2 and the load current are linearly changed, the circuit can provide a very reasonable magnitude of the switching level no matter the circuit works in any mode of light load, no load and heavy load, and the switching of the working mode can be realized in a reasonable time.
In a second aspect, the present invention relates to a method for mode switching of a voltage converter tracking a load current, the method comprising the voltage converter mode switching circuit tracking the load current according to the first aspect of the present invention.
Compared with the prior art, the load current tracking voltage converter mode switching circuit and the load current tracking voltage converter mode switching method have the advantages that the size of the inversion level of the linear adjustment mode control signal can be approximated along with the size of the load current, and reasonable work mode switching of the voltage converter in different load environments is guaranteed. The invention has ingenious conception and reasonable and effective method, fully considers various different load environments of the voltage converter and fully ensures the stability of the output voltage under different environments.
The present applicant has described and illustrated embodiments of the present invention in detail with reference to the accompanying drawings, but it should be understood by those skilled in the art that the above embodiments are merely preferred embodiments of the present invention, and the detailed description is only for the purpose of helping the reader to better understand the spirit of the present invention, and not for limiting the scope of the present invention, and on the contrary, any improvement or modification made based on the spirit of the present invention should fall within the scope of the present invention.
Claims (10)
1. A voltage converter mode switching circuit that tracks load current, comprising:
the circuit comprises a mode control unit and an adjusting unit; wherein the content of the first and second substances,
the mode control unit is used for generating a mode control signal and controlling the voltage converter to switch between a boosting mode and a voltage reduction mode based on the mode control signal;
and the adjusting unit is connected with the mode control unit and used for acquiring an output signal of an error comparator in the voltage converter and generating a feedback current so as to adjust the turnover level of the mode control signal in the mode control unit.
2. A load current tracking voltage converter mode switching circuit as claimed in claim 1 wherein:
the mode control unit comprises a first current source, a second current source, a first voltage-dividing resistor, a second voltage-dividing resistor, a current switching tube and an operational amplifier; wherein the content of the first and second substances,
the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series and then connected between the input current Vin and the ground;
the first current source I0 is connected in parallel to two ends of the second voltage-dividing resistor R2, one end of the second current source I1 is connected to the high-voltage end of the second voltage-dividing resistor R2, and the other end is connected to the drain of the current switching tube;
the source electrode of the current switching tube is grounded, and the grid electrode of the current switching tube is connected with the output end of the operational amplifier;
the positive phase input end of the operational amplifier is connected with a reference voltage Vref, the negative phase input end of the operational amplifier is connected with a connection point between the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 to receive the resistor voltage-dividing V-, and the output end of the operational amplifier outputs the mode control signal.
3. A load current tracking voltage converter mode switching circuit as claimed in claim 2, wherein:
the adjusting unit comprises a reference subunit, a comparison subunit and a mirror image subunit;
the reference subunit is configured to receive the input voltage Vin to generate a comparison reference voltage Vref1 and input the comparison reference voltage Vref1 into the comparison subunit;
the comparison subunit is connected with the reference subunit and the mirror subunit, and is used for receiving the comparison reference voltage and the output signal of the error comparator and generating a third current based on the comparison result of the comparison reference voltage and the output signal of the error comparator;
the mirror subunit is connected with the mode control unit and is used for mirroring the third current to the mode control unit.
4. A load current tracking voltage converter mode switching circuit as claimed in claim 3, wherein:
the reference subunit comprises a reference tube Mp1 and a reference current source Iref;
the source electrode of the reference tube Mp1 is connected with a power supply voltage, and the drain electrode and the grid electrode are grounded through the reference current source Iref;
and the drain and the gate of the reference tube Mp1 are used as the output of the reference subunit to provide a comparison reference voltage Vref1 for the comparison subunit.
5. A load current tracking voltage converter mode switching circuit as claimed in claim 4, wherein:
the comparison subunit comprises a first input tube, a second input tube, a current mirror and a bridging resistor;
the current mirror comprises MOS (metal oxide semiconductor) tubes in mirror image connection and two identical mirror image current sources;
the drain electrodes of the first input tube and the second input tube are respectively connected to the drain electrodes of the two MOS tubes, and the drain electrodes of the first input tube and the second input tube are respectively connected to the two mirror current sources;
the grid electrode of the first input tube is connected to the comparison reference voltage Vref1, and the grid electrode of the second input tube is connected to the output signal of the error comparator;
the bridging resistor is connected between the source electrode of the first input tube and the source electrode of the second input tube, and the drain electrode of the first input tube is used as the output of the comparison subunit and is connected with the mirror image subunit.
6. A load current tracking voltage converter mode switching circuit as claimed in claim 5, wherein:
and the output end of the mirror image subunit is electrically connected with the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 in the mode control unit.
7. A load current tracking voltage converter mode switching circuit as claimed in claim 6, wherein:
the feedback current is
Wherein k is the current mirror ratio of the mirror subunit,
V EAOUT is the output voltage of the error comparator,
and R is the bridging resistor.
8. A load current tracking voltage converter mode switching circuit as claimed in claim 7, wherein:
when the input voltage Vin gradually decreases, the inversion level of the mode control signal in the mode control unit is
When the input voltage Vin gradually rises, the inversion level of the mode control signal in the mode control unit is
9. A load current tracking voltage converter mode switching circuit as claimed in claim 8, wherein:
a flip level V of a mode control signal in the mode control unit in L And V in H A linear relationship with a load current of the voltage converter;
the lighter the rear-stage load of the voltage converter is, the lower the flip level V is in L And V in H The smaller the value of (c).
10. A method for mode switching a voltage converter that tracks load current, comprising:
the method is implemented using a load current tracking voltage converter mode switching circuit as claimed in any one of claims 1 to 9.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210969159.9A CN115411940A (en) | 2022-08-12 | 2022-08-12 | Load current tracking voltage converter mode switching circuit and method |
| PCT/CN2023/111006 WO2024032465A1 (en) | 2022-08-12 | 2023-08-03 | Load-current-tracking-based mode switching circuit and method for voltage converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210969159.9A CN115411940A (en) | 2022-08-12 | 2022-08-12 | Load current tracking voltage converter mode switching circuit and method |
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| Publication Number | Publication Date |
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| CN115411940A true CN115411940A (en) | 2022-11-29 |
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|---|---|---|---|
| CN202210969159.9A Pending CN115411940A (en) | 2022-08-12 | 2022-08-12 | Load current tracking voltage converter mode switching circuit and method |
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| Country | Link |
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| CN (1) | CN115411940A (en) |
| WO (1) | WO2024032465A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024032465A1 (en) * | 2022-08-12 | 2024-02-15 | 圣邦微电子(苏州)有限责任公司 | Load-current-tracking-based mode switching circuit and method for voltage converter |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5160210B2 (en) * | 2007-12-18 | 2013-03-13 | ルネサスエレクトロニクス株式会社 | DC-DC converter drive circuit |
| US8085005B2 (en) * | 2009-06-18 | 2011-12-27 | Micrel, Inc. | Buck-boost converter with sample and hold circuit in current loop |
| CN102983734B (en) * | 2012-12-20 | 2015-04-08 | 西安电子科技大学 | Soft starting circuit applied to voltage boosting DC-DC switch power supply |
| US9882488B2 (en) * | 2015-09-14 | 2018-01-30 | Intersil Americas LLC | Enhanced power mode transitions in buck-boost converters |
| CN114679051A (en) * | 2020-12-24 | 2022-06-28 | 圣邦微电子（北京）股份有限公司 | Multiphase DC-DC converter |
| CN115411940A (en) * | 2022-08-12 | 2022-11-29 | 圣邦微电子(苏州)有限责任公司 | Load current tracking voltage converter mode switching circuit and method |
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2022
- 2022-08-12 CN CN202210969159.9A patent/CN115411940A/en active Pending
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- 2023-08-03 WO PCT/CN2023/111006 patent/WO2024032465A1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024032465A1 (en) * | 2022-08-12 | 2024-02-15 | 圣邦微电子(苏州)有限责任公司 | Load-current-tracking-based mode switching circuit and method for voltage converter |
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| Publication number | Publication date |
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| WO2024032465A1 (en) | 2024-02-15 |
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