CN116613991A - Switch power supply converter with high output voltage precision hysteresis type AOT control - Google Patents

Switch power supply converter with high output voltage precision hysteresis type AOT control Download PDF

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Publication number
CN116613991A
CN116613991A CN202310677294.0A CN202310677294A CN116613991A CN 116613991 A CN116613991 A CN 116613991A CN 202310677294 A CN202310677294 A CN 202310677294A CN 116613991 A CN116613991 A CN 116613991A
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output voltage
voltage
vout
resistor
reference voltage
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CN202310677294.0A
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赵百鸣
林剑龙
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Hangzhou Yuanxin Semiconductor Technology Co ltd
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Hangzhou Yuanxin Semiconductor Technology Co ltd
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Priority to CN202310677294.0A priority Critical patent/CN116613991A/en
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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
    • 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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • H02M1/38—Means for preventing simultaneous conduction of switches
    • H02M1/385—Means for preventing simultaneous conduction of switches with means for correcting output voltage deviations introduced by the dead time
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application relates to a switching power supply converter with high output voltage precision hysteresis type AOT control, which comprises: the self-adaptive on time generation circuit generates on time by detecting the input voltage VIN and the output voltage VOUT, so that the switching frequency is fixed in a certain range in a wide input and output voltage range; the hysteresis comparator circuit based on reference voltage error compensation generates a compensated reference voltage VREFL by comparing the feedback voltage VFB with the reference VREF, so that the output voltage VOUT is accurately stabilized at a set value. The beneficial effects of the application are as follows: the self-adaptive on-time generator circuit has the characteristics of high switching frequency and quick transient response, and can realize the fixation of the switching frequency in a wide input and output voltage range, namely, the switching frequency is not changed along with the change of the input voltage VIN and the output voltage VOUT. Meanwhile, the compensated reference voltage VREFL is generated through the feedback voltage VFB, and the accuracy of the output voltage is improved.

Description

Switch power supply converter with high output voltage precision hysteresis type AOT control
Technical Field
The application relates to the technical field of switching power converters, in particular to a switching power converter with high output voltage precision hysteresis type AOT control.
Background
The switching power supply converter has wide application in the fields of photovoltaic energy storage, electric automobiles, big data centers and consumer electronics. The control mode of the switching power supply DC-DC converter may be classified into a voltage type and a current type in a detection mode, and may be classified into a fixed frequency and a fixed on/off time in a frequency control mode, etc. The traditional DC-DC converter adopts fixed frequency current type control, and then the transient response capability of a fixed frequency control mode is poor, namely when the output load suddenly changes, the output voltage can generate huge overshoot and undershoot, and the subsequent electronic system supplied with power by the fixed frequency control mode is failed. Compared with a hysteresis voltage type, the traditional current type detection mode needs a complex and accurate current detection circuit to carry out loop control, and meanwhile, the response speed and the switching frequency of the system are limited. In order to overcome the problems of instability such as overshoot and undershoot of the output voltage, speed and precision of the current mode detection circuit, a fixed on-time hysteresis type DC-DC switching power converter becomes a solution, as shown in fig. 1. The circuit consists of a fixed on time generating circuit, an output feedback resistor, a hysteresis comparator, a logic and half-bridge driving circuit, upper and lower switching tubes MH and ML, an inductor and an output capacitor. The working principle is as follows: as shown in fig. 2, at a fixed on time TON, the upper tube MH is turned on, the inductor current IL rises, and the output voltage VOUT also rises; when the on-time TON is timed out, the upper tube MH is turned off and the lower tube ML is turned on, and at the same time, the inductor current IL decreases, and the output voltage VOUT also decreases. The VOUT drop can be detected by feedback resistor networks R1 and R2 to obtain VFB. When VFB falls below reference voltage VREF, hysteresis comparator output VCMP toggles, turning off lower tube ML and turning on upper tube MH again through logic and half-bridge drive circuitry, and turning on the next switching cycle T. The period in which the upper management MH turns off and the lower management ML turns on becomes the off time TOFF. Therefore, the control mode only needs to detect the output voltage, and has simple loop and quick response; in addition, when the output load transient change occurs, the fixed on-time hysteresis control mode can respond to the load change by adjusting the off-time TOFF in one switching period, and compared with the control mode of fixed frequency or fixed period, the control mode enables the inductance current to respond to the load current change more quickly, reduces the overshoot and undershoot of the output voltage, and therefore achieves the rapid transient response of the output voltage.
However, since the valley of VFB is compared with the reference voltage VREF, there is an offset voltage VOS between the average value of VFB and the reference voltage, as shown in fig. 2. Since vout= (vfb+vos) × (r1+r2)/R1, the offset voltage VOS directly affects the accuracy of the output voltage VOUT. Under the conditions of different output capacitances, parasitic resistances and different inductor currents of the DC-DC converter, the ripple amplitude of the output voltage VOUT (i.e., the peak and valley voltage differences) is different, and the VOS offset voltage is also different, so that the accuracy of the output voltage is further affected. When the output voltage VOUT is low, for example, 1V supplies power to the CPU or GPU of the microprocessor, the output offset caused by the offset of VOS may occupy a larger proportion of VOUT, so that VOUT output accuracy is low, which results in degradation of the performance of the system. On the other hand, since the on-time TON is fixed, in the buck DC-DC converter, when the output voltage VIN or the output voltage VOUT changes, the duty ratio VOUT/VIN also changes. Since the switching period can be calculated as t=ton×vin/VOUT, the switching period or switching frequency may vary, which presents challenges for the selection of output capacitance, inductance, and output capacitance, and the design of the system.
Thus, challenges faced by conventional fixed frequency current-mode switching power converters and conventional fixed on-time hysteretic switching power converters include:
1. transient response capability of conventional fixed frequency DC-DC converter is poor
2. The traditional current type detection mode needs a complex and accurate current detection circuit to carry out loop control, so that the response speed and the switching frequency of the system are limited
3. The offset voltage VOS of the traditional hysteresis voltage type control mode can directly influence the precision of the output voltage VOUT
4. The traditional fixed on-time hysteresis control mode has large change of switching frequency in a wide input and output voltage range, and brings difficulty to the design of a system and the selection of filter inductance and capacitance
If not solved or optimally designed, the problems may cause systematic problems such as poor transient response capability, low switching frequency, large variation range, large system size, high cost, poor output precision and the like of the switching power supply converter.
Disclosure of Invention
The application aims at overcoming the defects of the prior art, and provides a switching power supply converter with high output voltage precision hysteresis type AOT control, which comprises:
the self-adaptive turn-on time generation circuit, a hysteresis comparator circuit based on reference voltage error compensation, a logic and half-bridge driving circuit, an upper switching tube, a lower switching tube, a feedback resistor network, an inductor and an output capacitor;
the self-adaptive on time generation circuit generates on time by detecting an input voltage VIN and an output voltage VOUT, so that the switching frequency is fixed in a certain range in a wide input and output voltage range;
according to the hysteresis comparator circuit based on reference voltage error compensation, the feedback voltage VFB and the reference VREF are compared to generate the compensated reference voltage VREFL, so that the output voltage VOUT is accurately stabilized at a set value, and high output voltage accuracy is realized.
Preferably, at the on time TON, the upper switching tube MH is turned on, the inductor current IL rises, and the output voltage VOUT also rises; when the on time TON is finished, the upper switching tube MH is turned off and the lower switching tube ML is turned on, at the moment, the inductance current IL is reduced, and meanwhile, the output voltage VOUT is also reduced; the output voltage VOUT drops and is detected by a feedback resistor network to obtain feedback voltage VFB, when the feedback voltage VFB drops below the compensated reference voltage VREFL, the output VCMP of the hysteresis comparator is turned over, the lower tube ML is turned off, the upper tube MH is turned on again through a logic and half-bridge driving circuit, and the next switching period T is turned on.
Preferably, the adaptive on-time generation circuit includes a voltage dividing resistor, a fifth resistor R5, a second capacitor C2, and a first comparator;
the input voltage VIN generates kVIN through voltage dividing resistor, and is converted into current I through fifth resistor R5 CHG For the firstThe two capacitors C2 are charged; when the voltage of the second capacitor C2 reaches the output voltage VOUT, the first comparator sends a high level pulse to end the on time TON of the upper switching tube MH;
the turn-on time is calculated as TON= (RC/k) x (VOUT/VIN), wherein R is the resistance value of the fifth resistor R5, and C is the capacitance value of the second capacitor C2;
the relation between the on time and the voltage conversion ratio is TON/T=VOUT/VIN, wherein T is the switching period; t is calculated to obtain: t=rc/k, since R, C and k are both constant, i.e. the switching period is constant and does not vary with the input and output voltages.
Preferably, the hysteresis comparator circuit based on reference voltage error compensation comprises a second comparator, an operational amplifier, a sixth resistor RD1, a seventh resistor Rs1 and a first N-type tube Mc1;
the compensated reference voltage VREFL is generated by flowing a first error compensation current ID1 generated by an op-amp through a sixth resistor RD1, and the calculation formula is as follows: vrefl=vref-IDRD, where VREF is the reference voltage.
Preferably, a harmonic compensation VSLP is introduced at the negative input of the second comparator to change the falling slope of the feedback voltage VFB.
Preferably, the hysteresis comparator circuit based on reference voltage error compensation includes an output voltage error detection and compensation sub-circuit and a hysteresis comparator sub-circuit;
in the hysteresis comparator circuit based on reference voltage error compensation, a final stable point of the output voltage VOUT is set by a first resistor R1 and a second resistor R2: vout=vref× (r1+r2)/R1;
when the output voltage VOUT is higher than the output stable point, the feedback voltage VFB is higher than the reference voltage VREF, and the output voltage VG2 thereof rises through the differential operational amplifier; the output voltage VG2 of the differential operational amplifier is converted into a second error compensation current ID2 through a second N-type tube Mc2 and an eighth resistor Rs2 and a two-stage current mirror; the output voltage VG2 rises, the second error compensation current ID2 increases, and the compensated reference voltage VREFL decreases since the reference voltage VREF is fixed; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the stable point of the output voltage VOUT is reduced;
when the output voltage VOUT is lower than the output stable point, the feedback voltage VFB is lower than the reference voltage VREF, and the output voltage VG2 thereof is reduced by the differential op-amp; the second error compensation current ID2 is also reduced and the compensated reference voltage VREFL is raised; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the output voltage VOUT is increased at a stable point.
The beneficial effects of the application are as follows:
1. the application controls the turn-on time of the upper tube MH through the self-adaptive turn-on time generator circuit, controls the turn-off time of the upper tube MH through the hysteresis comparator based on reference voltage error compensation, and realizes the cycle-by-cycle comparison of the feedback voltage VFB and the reference voltage through the feedback resistor network, thereby realizing the stable regulation of the output voltage. Meanwhile, the application adopts oblique wave compensation V SLP Techniques to alter the falling slope of the VFB to improve loop and system stability.
2. The application detects and obtains feedback voltage VFB through an output voltage feedback resistor network and a reference voltage error compensation circuit and compares the feedback voltage VFB with a voltage reference VREFL. According to the application, the reference voltage VREF of the hysteresis comparator is compensated and calibrated by generating compensation current through capacitance compensation, and the compensated reference voltage VREFL is obtained in a loop control mode, as shown in fig. 4, so that the voltage offset VOS is counteracted, and the accuracy of the output voltage is improved.
3. The application provides a self-adaptive on-time generator circuit, which can realize the fixation of switching frequency in a wide input and output voltage range by detecting an input voltage VIN and an output voltage VOUT to generate on-time, namely, the switching frequency is not changed along with the change of the input voltage VIN and the output voltage VOUT. Meanwhile, the compensated reference voltage VREFL is generated through the feedback voltage VFB, and the accuracy of the output voltage is improved.
Drawings
Fig. 1 is a schematic structural diagram of a conventional DC-DC converter with fixed on-time delay according to the present application;
fig. 2 is a schematic diagram of the working principle of a conventional DC-DC converter with fixed on-time delay according to the present application;
FIG. 3 is a schematic diagram of a switching power converter with high output voltage accuracy hysteretic AOT control according to the present application;
fig. 4 is a schematic diagram of a working principle of the switching power supply converter with high output voltage precision hysteresis AOT control according to the present application;
FIG. 5 is a schematic diagram of a hysteresis comparator circuit based on reference voltage error detection and compensation according to the present application;
fig. 6 is a schematic diagram of the working principle of reference voltage error detection and compensation provided by the application.
Fig. 7 is a schematic structural diagram of an adaptive on-time generator based on VIN and VOUT detection according to the present application.
Detailed Description
The application is further described below with reference to examples. The following examples are presented only to aid in the understanding of the application. It should be noted that it will be apparent to those skilled in the art that modifications can be made to the present application without departing from the principles of the application, and such modifications and adaptations are intended to be within the scope of the application as defined in the following claims.
Example 1:
as shown in fig. 1, 101 is an input circuit structure of the fixed on-time hysteresis type DC-DC converter, and 102 is a corresponding output circuit structure. However, as shown in fig. 2, the offset voltage VOS directly affects the accuracy of the output voltage VOUT. In this regard, the present application provides a switching power converter with high output voltage accuracy hysteretic AOT control, as shown in fig. 3, comprising: the self-adaptive on time generation circuit 201, a hysteresis comparator circuit 202 based on reference voltage error compensation, a logic and half-bridge driving circuit, an upper switching tube, a lower switching tube, a feedback resistor network, an inductor L and an output capacitor C.
Specifically, the upper and lower switching tubes comprise an upper switching tube MH and a lower switching tube ML, which are N-type tubes; the feedback resistor network comprises a first resistor R1 and a second resistor R2 which are connected; the output ends of the hysteresis comparator circuit and the self-adaptive on time generation circuit based on reference voltage error compensation are connected with the input ends of the logic and half-bridge driving circuit, and the two output ends of the logic and half-bridge driving circuit are respectively connected with the grid electrode of the upper switching tube MH and the grid electrode of the lower switching tube ML; the drain electrode of the upper switching tube MH is connected with the input voltage VIN, and the source electrode of the upper switching tube MH is respectively connected with the drain electrode of the lower switching tube ML and the inductor L through a branch node VSW; the source electrode of the lower switch tube ML is connected with the ground end; one end of the inductor L away from the branch node VSW is connected to the output voltage VOUT.
The working principle of the switching power supply converter with high output voltage precision hysteresis type AOT control is as follows: when the on time TON is reached, the upper switching tube MH is turned on, the inductor current IL rises, and the output voltage VOUT also rises; when the on time TON is finished, the upper switching tube MH is turned off and the lower switching tube ML is turned on, at the moment, the inductance current IL is reduced, and meanwhile, the output voltage VOUT is also reduced; the output voltage VOUT drops and is detected by a feedback resistor network to obtain feedback voltage VFB, when the feedback voltage VFB drops below the compensated reference voltage VREFL, the output VCMP of the hysteresis comparator is turned over, the lower tube ML is turned off, the upper tube MH is turned on again through a logic and half-bridge driving circuit, and the next switching period T is turned on.
The adaptive on-time generation circuit 201 according to the embodiment of the present application generates on-time by detecting the input voltage VIN and the output voltage VOUT, so as to fix the switching frequency in a certain range within a wide input and output voltage range.
Specifically, as shown in fig. 7, the adaptive on-time generation circuit 201 includes a voltage dividing resistor, a fifth resistor R5, a second capacitor C2, and a first comparator; the voltage dividing resistor includes a third resistor R3 and a fourth resistor R4. One end of the fourth resistor R4 is connected to the input voltage VIN, the other end is connected to one end of the third resistor R3, and the other end of the third resistor is connected to the ground. A node is led out between the third resistor R3 and the fourth resistor R4 and is connected with the positive input end of the operational amplifier, the negative input end of the operational amplifier is connected with the ground end through the fifth resistor R5, and the output end of the operational amplifier is connected with the grid electrode of the third N-type tube MN 3; the source electrode of the third N-type tube MN3 is connected with the ground end through a fifth resistor R5, and the drain electrode of the third N-type tube MN3 is connected with the differential pair circuit. The differential pair circuit consists of a first P-type tube MP1 and a second P-type tube MP2, wherein the grid electrodes of the first P-type tube MP1 and the second P-type tube MP2 are connected, and the drain electrode of the second P-type tube MP2 is respectively connected with a second capacitor C2 and the positive input end of the first comparator. In addition, the self-adaptive turn-on time generation circuit further comprises a fourth N-type tube MN4, the drain electrode of the fourth N-type tube MN4 is connected with the positive input end of the first comparator, and the source electrode of the fourth N-type tube MN4 is connected with the ground end.
The working principle of the self-adaptive on time generation circuit is as follows: first, the voltage of VIN is detected by a voltage dividing resistor to generate kVIN, and then the kVIN is converted into current I by a fifth resistor R5 CHG Charging the second capacitor C2 achieves that the second capacitor C2 is charged with a current (kVIN/R) proportional to the input voltage VIN. When the charging is performed to make the voltage of the second capacitor C2 reach the output voltage VOUT, the first comparator sends a high level pulse to end the On Time TON (On-Time) of the upper switching tube MH;
the turn-on time is calculated as TON= (RC/k) x (VOUT/VIN), wherein R is the resistance value of the fifth resistor R5, and C is the capacitance value of the second capacitor C2; as can be seen, the on time TON is proportional to the output voltage VOUT and inversely proportional to the input voltage VIN;
correspondingly, in the buck switching power supply controller, the relation between the on time and the voltage conversion ratio is TON/T=VOUT/VIN, wherein T is the switching period; t is calculated to obtain: t=rc/k, since R, C and k are both constant, i.e. the switching period or switching frequency is constant and does not vary with the input and output voltages.
Therefore, the self-adaptive on-time generator circuit provided by the embodiment of the application can realize that the switching frequency is not changed along with the change of the input voltage VIN and the output voltage VOUT, namely, the switching frequency is fixed in a certain range in a wide input and output voltage range, which is beneficial to the selection of filter inductance and inductance in a system, the design of electromagnetic interference suppression and the stability of the system.
In addition, the hysteresis comparator circuit 202 based on reference voltage error compensation provided by the embodiment of the application enables the output voltage VOUT to be accurately stabilized at the set value by comparing the feedback voltage VFB with the compensated reference voltage VREFL, thereby realizing high output voltage accuracy.
Specifically, the hysteresis comparator circuit 202 based on reference voltage error compensation includes a second comparator, an operational amplifier, a sixth resistor RD1, a seventh resistor Rs1, and a first N-type tube Mc1.
The output end of the second comparator is connected with the logic and half-bridge driving circuit; a node is arranged between the first resistor R1 and the second resistor R2 and is connected with the negative input end of the second comparator, the drain electrode of the first N-type tube Mc1 and the sixth resistor RD1 are connected to the same node, and the node is connected with the positive input end of the second comparator. The source of the first N-type tube Mc1 is connected to the ground terminal through a seventh resistor Rs 1. In addition, the positive input terminal and the negative input terminal of the operational amplifier respectively input the feedback voltage VFB and the reference voltage VREF.
The compensated reference voltage VREFL is generated by flowing a first error compensation current ID1 generated by an op-amp through a sixth resistor RD, and the calculation formula is as follows: vrefl=vref-IDRD, where VREF is the reference voltage.
In addition, the embodiment of the application introduces the harmonic compensation VSLP at the negative input end of the second comparator to change the falling slope of the feedback voltage VFB, thereby improving the stability of the loop and the system.
The logic and half-bridge driving circuit can provide overvoltage and undervoltage protection and soft start functions of the output and can quickly drive the upper tube MH and the lower tube ML through level conversion. The logic section also includes a basic dead zone control circuit to prevent the upper and lower tubes from passing through. The self-adaptive on-time AOT hysteresis control switching power supply converter has high output precision, quick transient response and high switching frequency, can be widely applied to DC-DC converters with high output voltage and high current, such as silicon, gallium nitride, silicon carbide and other application fields, can reduce the size and cost of a system scheme, and improves the reliability and stability of the system.
Example 2:
on the basis of embodiment 1, embodiment 2 of the present application provides another hysteresis comparator circuit based on reference voltage error compensation, as shown in fig. 5, including an output voltage error detection and compensation sub-circuit 301 and a hysteresis comparator sub-circuit 302.
In the hysteresis comparator circuit based on reference voltage error compensation, the final stable point of the output voltage VOUT is set by the first resistor R1 and the second resistor R2: vout=vref× (r1+r2)/R1.
As shown in fig. 6, when the output voltage VOUT is higher than the output stable point, the feedback voltage VFB is higher than the reference voltage VREF, and the output voltage VG2 rises through the differential op-amp; the output voltage VG2 of the differential operational amplifier is converted into a second error compensation current ID2 through a second N-type tube Mc2 and an eighth resistor Rs2 and a two-stage current mirror; the output voltage VG2 rises, the second error compensation current ID2 increases, and the compensated reference voltage VREFL decreases since the reference voltage VREF is fixed; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the output voltage VOUT is dropped at a stable point.
Similarly, when the output voltage VOUT is lower than the output stable point, the feedback voltage VFB is lower than the reference voltage VREF, and the output voltage VG2 thereof is reduced by the differential op-amp; the second error compensation current ID2 is also reduced and the compensated reference voltage VREFL is raised; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the output voltage VOUT is increased at a stable point.
Therefore, the embodiment of the application can accurately stabilize the output voltage at the set value by detecting the error of the output voltage to generate the compensation current and comparing the feedback voltage with the compensated reference voltage, thereby realizing the purpose of high output voltage precision.
In summary, according to the application, the output voltage is detected and compared with the voltage reference through the output voltage feedback resistor network and the reference voltage error compensation circuit, the reference voltage of the hysteresis comparator is compensated and calibrated through the compensation current generated by capacitance compensation, the compensated reference voltage VREFL is obtained through loop control, and the precision of the output voltage is improved. The circuit has the characteristic of quick transient response of the self-adaptive on-time AOT switching power supply converter, and secondly, compared with a traditional current type control mode, the hysteresis type control mode also has the characteristics of high switching frequency and quick transient response. Finally, the self-adaptive on-time generator circuit provided by the application can realize the fixation of the switching frequency in a wide input and output voltage range, namely, the switching frequency is not changed along with the change of the input voltage VIN and the output voltage VOUT. The hysteresis type AOT controlled switching power supply converter circuit can be widely applied to various DC-DC converters with output voltage and output current, such as silicon, gallium nitride, silicon carbide and other application fields, and can greatly improve the switching frequency to reduce the scheme size of the system, improve the voltage output precision and the transient response performance of the system and improve the reliability and stability of the system.

Claims (6)

1. The switching power supply converter with the high-output voltage precision hysteresis type AOT control is characterized by comprising a self-adaptive on time generation circuit, a hysteresis comparator circuit based on reference voltage error compensation, a logic and half-bridge driving circuit, an upper switching tube, a lower switching tube, a feedback resistor network, an inductor and an output capacitor;
the self-adaptive on time generation circuit generates on time by detecting an input voltage VIN and an output voltage VOUT, so that the switching frequency is fixed in a certain range in a wide input and output voltage range;
according to the hysteresis comparator circuit based on reference voltage error compensation, the feedback voltage VFB and the reference VREF are compared to generate the compensated reference voltage VREFL, so that the output voltage VOUT is accurately stabilized at a set value, and high output voltage accuracy is realized.
2. The switching power converter with high output voltage accuracy hysteretic AOT control of claim 1, wherein at turn-on time TON, upper switching tube MH is turned on, inductor current IL rises, and output voltage VOUT also rises; when the on time TON is finished, the upper switching tube MH is turned off and the lower switching tube ML is turned on, at the moment, the inductance current IL is reduced, and meanwhile, the output voltage VOUT is also reduced; the output voltage VOUT drops and is detected by a feedback resistor network to obtain feedback voltage VFB, when the feedback voltage VFB drops below the compensated reference voltage VREFL, the output VCMP of the hysteresis comparator is turned over, the lower tube ML is turned off, the upper tube MH is turned on again through a logic and half-bridge driving circuit, and the next switching period T is turned on.
3. The switching power supply converter with high output voltage accuracy hysteretic AOT control of claim 2, wherein the adaptive on-time generation circuit comprises a divider resistor, a fifth resistor R5, a second capacitor C2, and a first comparator;
the input voltage VIN generates kVIN through voltage dividing resistor, and is converted into current I through fifth resistor R5 CHG Charging the second capacitor C2; when the voltage of the second capacitor C2 reaches the output voltage VOUT, the first comparator sends a high level pulse to end the on time TON of the upper switching tube MH;
the turn-on time is calculated as TON= (RC/k) x (VOUT/VIN), wherein R is the resistance value of the fifth resistor R5, and C is the capacitance value of the second capacitor C2;
the relation between the on time and the voltage conversion ratio is TON/T=VOUT/VIN, wherein T is the switching period; t is calculated to obtain: t=rc/k, since R, C and k are both constant, i.e. the switching period is constant and does not vary with the input and output voltages.
4. The switching power supply converter with high output voltage accuracy hysteretic AOT control of claim 2, wherein the hysteretic comparator circuit based on reference voltage error compensation comprises a second comparator, an op-amp, a sixth resistor RD1, a seventh resistor Rs1, and a first N-type tube Mc1;
the compensated reference voltage VREFL is generated by flowing a first error compensation current ID1 generated by an op-amp through a sixth resistor RD1, and the calculation formula is as follows: vrefl=vref-IDRD, where VREF is the reference voltage.
5. The switching power supply converter with high output voltage accuracy hysteretic AOT control of claim 4 wherein harmonic compensation VSLP is introduced at the negative input of the second comparator to vary the falling slope of the feedback voltage VFB.
6. The switching power supply converter with high output voltage accuracy hysteretic AOT control of claim 2, wherein the hysteretic comparator circuit based on reference voltage error compensation comprises an output voltage error detection and compensation subcircuit and a hysteretic comparator subcircuit;
in the hysteresis comparator circuit based on reference voltage error compensation, a final stable point of the output voltage VOUT is set by a first resistor R1 and a second resistor R2: vout=vref× (r1+r2)/R1;
when the output voltage VOUT is higher than the output stable point, the feedback voltage VFB is higher than the reference voltage VREF, and the output voltage VG2 thereof rises through the differential operational amplifier; the output voltage VG2 of the differential operational amplifier is converted into a second error compensation current ID2 through a second N-type tube Mc2 and an eighth resistor Rs2 and a two-stage current mirror; the output voltage VG2 rises, the second error compensation current ID2 increases, and the compensated reference voltage VREFL decreases since the reference voltage VREF is fixed; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the stable point of the output voltage VOUT is reduced;
when the output voltage VOUT is lower than the output stable point, the feedback voltage VFB is lower than the reference voltage VREF, and the output voltage VG2 thereof is reduced by the differential op-amp; the second error compensation current ID2 is also reduced and the compensated reference voltage VREFL is raised; the feedback voltage VFB is compared with the compensated reference voltage VREFL by the third comparator, so that the output voltage VOUT is increased at a stable point.
CN202310677294.0A 2023-06-08 2023-06-08 Switch power supply converter with high output voltage precision hysteresis type AOT control Pending CN116613991A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117706187A (en) * 2024-02-06 2024-03-15 杭州元芯半导体科技有限公司 Inductor current sampling circuit and inductor current sampling method of half-bridge driving chip

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117706187A (en) * 2024-02-06 2024-03-15 杭州元芯半导体科技有限公司 Inductor current sampling circuit and inductor current sampling method of half-bridge driving chip
CN117706187B (en) * 2024-02-06 2024-04-12 杭州元芯半导体科技有限公司 Inductor current sampling circuit and inductor current sampling method of half-bridge driving chip

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