CN-121261537-B - Wide input buck-boost switching power supply converter and control method

CN121261537BCN 121261537 BCN121261537 BCN 121261537BCN-121261537-B

Abstract

The invention discloses a wide-input buck-boost switching power supply converter and a control method thereof, wherein the converter comprises an error amplifying module, a current sampling circuit, a comparator array, a conduction time generator, a turn-off time generator, a dynamic mode selection circuit, a logic control circuit, a zero crossing detection circuit and a four-way power switching tube module; the efficiency and performance of the converter are optimized by introducing the self-adaptive constant on-off on-time generator and the self-adaptive constant off-time generator, smooth transition is realized between different working modes by accurately adjusting the on-time and the off-time, the stability and the efficiency of the converter are improved, the accurate adjustment of the output voltage is efficiently and stably realized within a wide input voltage range, and the converter has excellent input adaptability. And the self-adaptive constant on-time control is adopted in the buck mode, and the self-adaptive constant off-time control is adopted in the boost mode, so that the system keeps optimized dynamic response and stability under different conversion conditions.

Inventors

QIAN LIBO
LI ZONGHUI
LI YANI
WANG XIUDENG
LI YONGYUAN
ZHU ZHANGMING

Assignees

西安电子科技大学

Dates

Publication Date: 20260512
Application Date: 20251029

Claims (10)

1. A wide input buck-boost switching power converter, comprising: The device comprises an error amplifying module, a current sampling circuit, a comparator array, a conduction time generator, a turn-off time generator, a dynamic mode selection circuit, a logic control circuit, a zero crossing detection circuit and a four-way power switch tube module, The error amplifying module adopts a type II compensation network, obtains an output voltage signal through a feedback resistor network of the error amplifying module, and outputs an error voltage after comparing the output voltage signal with a reference voltage; the current sampling circuit is used for collecting corresponding currents in the four paths of power switch tube modules in real time and generating corresponding current detection signals; The comparator triggers the corresponding on-time generator and off-time generator by comparing the current detection signal with the error voltage; the on-time generator counts on-time according to the input voltage and the output voltage under the triggering of the corresponding comparator and outputs an on-time control signal; The turn-off time generator counts turn-off time according to the input voltage and the output voltage under the triggering of the corresponding comparator and outputs a turn-off time control signal; the dynamic mode selection circuit outputs a corresponding mode selection signal according to the relation between the input voltage and the output voltage; The logic control circuit generates driving signals corresponding to different modes according to the mode selection signals, the on-time control signals and the off-time control signals, and detects zero crossing points of currents of load inductors in the four-way power switching tube module through the zero crossing detection circuit to determine whether the converter enters a light load mode or not, and a pause working phase is introduced in the light load mode so as to enable the converter to perform pulse cross period modulation to reduce the frequency and loss of the converter; And the four-way power switch tube module outputs corresponding conversion voltage according to driving signals corresponding to different modes.
2. The wide input buck-boost switching power converter of claim 1, wherein the error amplification module includes: A feedback resistor network, an error amplifier and a type II compensation network, wherein, The input end of the feedback resistor network is connected with an output voltage signal, and the output end of the feedback resistor network is connected with the inverting input end of the error amplifier; The non-inverting input end of the error amplifier is connected with reference voltage, and the output end of the error amplifier is used as the output end of the error amplifying module; The input end of the type II compensation network is connected with the output end of the feedback resistor network, and the output end of the type II compensation network is connected with the output end of the error amplifier.
3. The wide input buck-boost switching power converter of claim 1, wherein the current sense signal includes a valley current and a peak current, wherein the comparator array triggers the corresponding on-time generator and off-time generator by comparing the current sense signal to an error voltage, comprising: A first comparator in the comparator array compares the voltage V CS_BK corresponding to the valley current with the error voltage V EA , and when V EA is larger than V CS_BK , a first trigger signal CMP BK is output to trigger the on-time generator; And a second comparator in the comparator array compares the voltage V CS_BT corresponding to the peak current with the error voltage V EA , and when V EA is smaller than V CS_BT , a second trigger signal CMP BT is output to trigger the turn-off time generator.
4. A wide input buck-boost switching power converter according to claim 3, wherein the on-time generator, triggered by the corresponding comparator, counts on-time based on the input voltage and the output voltage, and outputs an on-time control signal, comprising: When the input voltage V IN is greater than the output voltage V OUT under the triggering of the first comparator, the on-time generator outputs the on-signal T ON_BK according to the input voltage V IN , the output voltage V OUT and the first trigger signal CMP BK , and outputs the on-time control signal PWM BK through the RS trigger in the on-time generator.
5. A wide input buck-boost switching power converter according to claim 3, wherein the off-time generator, triggered by the corresponding comparator, counts off-time according to the input voltage and the output voltage, outputs an off-time control signal, comprising: The turn-off time generator outputs a turn-off signal T OFF_BT according to the input voltage V IN , the output voltage V OUT and the second trigger signal CMP BT by the turn-off time generation circuit in the turn-off time generator when the input voltage V IN is smaller than the output voltage V OUT under the triggering of the second comparator, and outputs a turn-off time control signal PWM BT through the RS trigger in the turn-off time generator.
6. The converter of claim 1, wherein the dynamic mode selection circuit outputs a corresponding mode selection signal according to a relationship between an input voltage and an output voltage, comprising: When the input voltage V IN is greater than the output voltage V OUT , the dynamic mode selection circuit outputs the enable signal EN BK of high level, the enable signal EN BB of low level and the enable signal EN BT of low level as mode selection signals corresponding to the Buck mode; When the input voltage V IN is smaller than the output voltage V OUT , the dynamic mode selection circuit outputs the enable signal EN BT of high level, the enable signal EN BB of low level and the enable signal EN BK of low level as mode selection signals corresponding to Boost modes; When the difference between the input voltage V IN and the output voltage V OUT is within the preset range, the dynamic mode selection circuit outputs the enable signal EN BB with high level, the enable signal EN BK with low level and the enable signal EN BT with low level as mode selection signals corresponding to the Buck-Boost mode.
7. The converter of claim 6, wherein the logic control circuit generates the driving signals corresponding to different modes according to the mode selection signal, the on-time control signal, and the off-time control signal, comprising: The logic control circuit outputs an adaptive constant on-time control signal as a driving signal corresponding to the Buck mode according to a mode selection signal and an on-time control signal corresponding to the Buck mode; According to a mode selection signal and a turn-off time control signal corresponding to the Boost mode, outputting an adaptive constant turn-off time control signal as a driving signal corresponding to the Boost mode; And outputting a quasi-fixed frequency reduction modulation signal as a driving signal corresponding to the Buck-Boost mode according to a mode selection signal, an on-time control signal and an off-time control signal corresponding to the Buck-Boost mode.
8. The converter of claim 7, wherein the four-way power switching tube module outputs corresponding switching voltages according to driving signals corresponding to different modes, and the converter comprises: When the driving signal is a driving signal corresponding to a Buck mode and the error voltage V EA is larger than the voltage V CS_BK corresponding to the valley current, the four-way power switching tube module controls the switching tube M A and the switching tube M D to be conducted, and after the conduction time generator is in a preset conduction time, the switching tube M A of the four-way power switching tube module is controlled to be turned off, the switching tube M B and the switching tube M D are controlled to be conducted, and corresponding conversion voltage is output; When the driving signal is a driving signal corresponding to a Boost mode, and the error voltage V EA is smaller than the voltage V CS_BT corresponding to the peak current, the four-way power switching tube module controls the switching tube M A and the switching tube M D to be turned on, and after the turn-off time generator is subjected to preset turn-off time, the switching tube M A of the four-way power switching tube module is controlled to be turned off, the switching tube M C is controlled to be turned on, and the corresponding conversion voltage is output; When the driving signal is a driving signal corresponding to a Buck-Boost mode, the error voltage V EA is larger than the voltage V CS_BK corresponding to the valley current, the four-way power switching tube module controls the switching tube M A and the switching tube M D to be conducted, the switching tube M A and the switching tube M C to be conducted after the conduction time generator passes through a preset conduction time, when the error voltage V EA is smaller than the voltage V CS_BT corresponding to the peak current, the four-way power switching tube module controls the switching tube M A and the switching tube M D to be conducted, and controls the switching tube M A and the switching tube M B to be conducted and the switching tube M D to be conducted after the turn-off time generator passes through a preset turn-off time, and corresponding conversion voltage is output.
9. The converter of claim 1, wherein the zero crossing detection circuit detects zero crossing points of current of the load inductor in the four-way power switching tube module to determine whether the converter enters a light load mode, and when the light load mode, a pause operation phase is introduced to make the converter perform pulse cross period modulation, and the process comprises: When the zero-crossing detection circuit detects that the load current of the load inductor in the four-way power switch tube module is smaller than a preset zero-current detection threshold value, the converter enters a light load mode, a pause stage is activated, the converter carries out pulse cross period modulation, and after the pause stage is kept until the error voltage V EA is larger than the voltage V CS_BK corresponding to the valley current, the converter is controlled to resume a normal working state.
10. A wide input buck-boost switching power supply conversion control method, applied to the wide input buck-boost switching power supply converter according to any one of claims 1 to 9, comprising: The feedback resistor network in the error amplifying module is utilized to acquire an output voltage signal, and the output voltage signal is compared with a reference voltage to output an error voltage; Collecting inductance current in real time by using a current sampling circuit and generating a corresponding current detection signal; Comparing the current detection signal with the error voltage by using a comparator, and triggering a corresponding on-time generating circuit and off-time generating circuit; the on-time generator counts the on-time according to the input voltage and the output voltage under the triggering of the corresponding comparator, and outputs an on-time control signal; The turn-off time generator counts turn-off time according to the input voltage and the output voltage under the triggering of the corresponding comparator and outputs a turn-off time control signal; outputting a corresponding mode selection signal according to the relation between the input voltage and the output voltage by using a dynamic mode selection circuit; The zero crossing point of the current of the load inductor in the four-way power switching tube module is detected through a zero crossing detection circuit so as to determine whether the converter enters a light load mode or not, and a pause working phase is introduced in the light load mode so as to enable the converter to enter a pulse cross period modulation mode, thereby reducing the frequency and loss of the converter; and controlling the four-way power switch tube module to output corresponding conversion voltage according to the driving signals corresponding to different modes.

Description

Wide input buck-boost switching power supply converter and control method Technical Field The invention belongs to the field of power converters in power management circuits, and particularly relates to a wide-input buck-boost switching power converter and a control method. Background With the popularity of portable electronic devices, especially smart phones, tablet computers, wearable devices, etc., the requirements for power management systems are also increasing. Especially in the face of large input voltage fluctuations, how to ensure that a power supply system can provide a stable output voltage becomes an important challenge in design. Buck-Boost converters (Buck-Boost converters) are widely used in these applications as a type of Converter that can provide a stable output under different input voltage conditions. However, the existing Buck-Boost converter still has many disadvantages in terms of efficiency, mode switching, noise suppression, etc., especially low efficiency under light load conditions, and may generate large voltage fluctuations and electromagnetic interference (EMI) when switching between different operation modes (such as Buck mode, boost mode, and Buck-Boost mode). Existing buck-boost converters mostly employ constant on-time (COT) control or peak current mode control strategies that can provide relatively stable output voltages in some cases. However, when the load change is large, the conventional methods are easy to have the problems of unstable efficiency, voltage fluctuation, high electromagnetic interference and the like. During the mode switching process of the Buck-Boost converter, especially when the Buck mode is switched to the Boost mode, fluctuation or instability of the output voltage is easily caused due to mismatching of the change of the inductance current and hysteresis of the feedback loop. Such fluctuations not only affect the proper operation of the device, but may also interfere with surrounding electronic devices, resulting in electromagnetic interference (EMI) problems. In addition, the light load efficiency problem is also a significant challenge faced by conventional Buck-Boost converters. Under the light load condition, many traditional control methods can not be effectively switched to a low-frequency working state, so that the switching loss is too high, and the efficiency is obviously reduced. While some existing designs attempt to improve this problem by adjusting the control strategy, they tend to have difficulty achieving desirable efficiency over a wide load range, especially with limited efficiency improvement at low power demands. The existing Buck-Boost converter has the following defects: The control loop design is complex and difficult to unify, and in the prior art, different types of control strategies are often required for buck, boost and buck-boost modes. For example, peak current mode control is required to cope with subharmonic instability problems at duty ratios greater than 50% in buck mode, typically with additional slope compensation, while in boost mode the system is affected by the right half-plane zero, limiting dynamic performance. At present, a unified control architecture applicable to all three working modes is lacking, so that the control system is complex in design and difficult in adjustment of a compensation network. The complex time sequence generation and the frequency stability have the defects that most of the existing Buck-Boost solutions adopt a modulation mode based on a fixed frequency and a fixed clock, and have limitations in transient response performance and loop design flexibility. Although alternatives such as fixed off-time control have been applied in single Buck or Boost converters, it is difficult to achieve seamless adaptive off-time generation in all operating regions by a single circuit in the prior art due to the different off-time calculation manners of Buck and Boost modes, and thus true quasi-constant switching frequency operation cannot be achieved in the full operating range. The performance and energy efficiency of the transition region are difficult to optimize, the existing Buck-Boost converter is usually required to be switched among three modes of Buck, boost and Buck-Boost transition regions, and the switching threshold value among the modes is difficult to accurately judge. Operation in the transition region where the input voltage approaches the output voltage is one of the core challenges of this type of converter design. The size of the region and the detection mechanism directly affect the smoothness of mode switching, the output ripple size, and the overall system efficiency. The prior art often lacks self-adaptive optimization capability for the size of a transition region, and is difficult to ensure smooth transition between modes and simultaneously consider light load efficiency and steady-state performance. In view of the foregoing, the existing Buck-Boost converter still has dra