WO2017156840A1 - 直流-直流转换器的控制电路 - Google Patents

直流-直流转换器的控制电路 Download PDF

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Publication number
WO2017156840A1
WO2017156840A1 PCT/CN2016/081221 CN2016081221W WO2017156840A1 WO 2017156840 A1 WO2017156840 A1 WO 2017156840A1 CN 2016081221 W CN2016081221 W CN 2016081221W WO 2017156840 A1 WO2017156840 A1 WO 2017156840A1
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Prior art keywords
output
converter
voltage
switch
control circuit
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PCT/CN2016/081221
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English (en)
French (fr)
Inventor
曹丹
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深圳市华星光电技术有限公司
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Priority to US15/114,555 priority Critical patent/US10177656B2/en
Publication of WO2017156840A1 publication Critical patent/WO2017156840A1/zh

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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
    • 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3696—Generation of voltages supplied to electrode drivers
    • 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
    • H02M3/157—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 with digital control
    • 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0264—Details of driving circuits
    • G09G2310/0275—Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/025—Reduction of instantaneous peaks of current

Definitions

  • the present invention generally relates to the technical field of liquid crystal display driving circuits, and more particularly to a control circuit for a DC-DC converter.
  • the DC-DC converter is mostly a current control mode.
  • the current control mode is to compare the current sampling signal with the output signal of the error amplifier at the input of the pulse width comparator to control the output pulse.
  • the duty cycle causes the output peak current to follow the error voltage variation.
  • the current control mode DC-DC converter samples the output voltage signal, the circuit also collects the current signal on the inductor; the transconductance converter (GM) receives the feedback voltage of the output voltage and the reference voltage, and outputs the processing result.
  • the result of summing the current detecting circuit and the triangular wave generating circuit is output to the non-inverting input terminal of the comparator, and the comparator outputs a driving signal for controlling the opening and closing of the power tube. Because the transconductance converter requires loop compensation, resulting in a multiple phase delay between the input and output, resulting in longer response times, resulting in slower transients that ultimately affect system stability.
  • the object of the present invention is to provide a novel DC-DC converter control circuit, which effectively solves the problem that the current control mode DC-DC converter has a long response time due to a multi-level phase delay between input and output.
  • the present invention provides a control circuit for a DC-DC converter, comprising: an error amplifier, an oscillator; a first input of the error amplifier receiving a feedback voltage, and a second input of the error amplifier Receiving a reference voltage; an output of the error amplifier is coupled to an input of the oscillator to provide an output of the error amplifier to the oscillator; an output of the oscillator to frequency and the error amplifier
  • the output proportional signal is output to the switch drive module of the DC-DC converter to control the charge and discharge time of the switch drive module.
  • a multiplier is further included, the first input of the error amplifier receiving the feedback voltage via the multiplier, wherein a first input of the multiplier receives the feedback voltage, a second input of the multiplier The terminal receives the parameter offset value; the output of the multiplier is coupled to the first input of the error amplifier.
  • the parameter compensation value is a compensation value of an expected voltage value at an output end of the DC-DC converter; the parameter compensation value is calculated by a voltage compensation module in an integrated circuit of a DC-DC converter; different DC-DC conversion
  • the parameter compensation value corresponding to the expected voltage value at the output of the device is also different, and the parameter compensation value is inversely proportional to the expected voltage value.
  • the parameter compensation value is less than 1.
  • the frequency of the signal at the output of the oscillator is inversely proportional to the discharge time of the switch drive module.
  • the switch drive module of the DC-DC converter is connected to the output of the DC-DC converter via an energy storage module.
  • the control circuit of the DC-DC converter further includes a voltage dividing circuit, and the feedback voltage is a voltage dividing value obtained by the output voltage of the DC-DC converter output through the voltage dividing circuit.
  • the reference voltage is greater than the feedback voltage.
  • the voltage dividing circuit includes a first resistor and a second resistor; at least one of the first resistor R 1 and the second resistor R 2 is a variable resistor.
  • the switch drive module includes a driver, a first switch for controlling charging of the energy storage module of the DC-DC converter, and a second switch for controlling discharge of the energy storage module;
  • the driver controls the conduction states of the first switch and the second switch according to a signal outputted by the output of the oscillator, wherein the first switch is opposite to the second switch.
  • the first input of the error amplifier is an inverting input
  • the second input of the error amplifier is a non-inverting input
  • the signal whose frequency is proportional to the output of the error amplifier is a rectangular wave signal.
  • the invention provides a DC-DC converter control circuit, through an error amplifier and an oscillator, the output voltage of the DC-DC converter output terminal reaches an expected voltage value and remains stable; when it is necessary to change the output end of the DC-DC converter
  • the feedback voltage is received by setting the multiplier, and then multiplied by the parameter compensation value to obtain the output voltage of the output of the multiplier;
  • the error amplifier is based on The amplified signal generated by the output voltage of the multiplier output and the reference voltage determines the frequency of the oscillator output signal, the frequency determines the periodic operating state of the switch driving module, and finally the output voltage of the DC-DC converter output terminal is reached.
  • the expected expected voltage value after the change is stable.
  • the control circuit effectively shortens the response time, thereby making the transient faster and significantly improving the stability of the system.
  • FIG. 1 is a schematic diagram showing a control circuit of a DC-DC converter according to an embodiment of the present invention.
  • FIG. 2 shows a specific example of the control circuit of FIG. 1.
  • Fig. 3 shows a control circuit of another embodiment of the present invention.
  • FIG. 1 is a schematic diagram showing a control circuit of a DC-DC converter according to an embodiment of the present invention.
  • a control circuit 100 for a DC-DC converter is provided in an embodiment of the present invention, including an error amplifier EA and an oscillator 110.
  • the inverting input of the error amplifier EA receives the feedback voltage V FB from the output voltage Vcore of the output of the DC-DC converter; the non-inverting input of the error amplifier EA receives the reference voltage V ref , and the reference voltage V ref is smaller than the DC-DC converter
  • the output voltage Vcore of the output terminal of the error amplifier EA is the processing result of the comparison value of the reference voltage V ref and the feedback voltage V FB .
  • the reference voltage V ref is greater than the feedback voltage V FB .
  • the input end of the oscillator 110 receives the error signal ⁇ V, and the output of the oscillator 110 outputs the signal to the switch drive module 120 of the DC-DC converter to control the charge and discharge time of the switch drive module 120, thereby converting the DC-DC conversion.
  • the output voltage Vcore at the output of the device is regulated until the desired voltage value is reached and remains stable.
  • the frequency of the signal at the output of oscillator 110 is inversely proportional to the discharge time of switch drive module 120.
  • the frequency of the signal at the output of the oscillator 110 is proportional to the error signal ⁇ V, that is, the larger the error signal ⁇ V is, the higher the frequency of the signal corresponding to the output of the oscillator, and the smaller the error signal ⁇ V is, the more the frequency of the signal corresponding to the output of the oscillator is. small.
  • the control circuit 100 of the DC-DC converter further includes a voltage dividing circuit 130, and the feedback voltage V FB is a divided voltage value obtained by the voltage dividing circuit 130 from the output voltage Vcore at the output of the DC-DC converter.
  • the switch drive module 120 receives the input DC voltage Vin; the switch drive module 120 of the DC-DC converter is connected to the output of the DC-DC converter through the energy storage module 140.
  • the working process of the control circuit 100 of the DC-DC converter provided by this embodiment is:
  • the switch drive module 120 periodically alternates charging and discharging.
  • the time t 1 of each charging cycle is fixed, that is, the charging time t 1 is fixed.
  • the time t 2 of each discharge cycle varies depending on the frequency of the signal at the output of the oscillator. Specifically, the time t 2 of the discharge period is inversely proportional to the frequency of the signal at the output of the oscillator 110, that is, the larger the frequency of the signal output from the oscillator 110, the smaller the time t 2 of the discharge period, and thus the overall discharge time is reduced. .
  • the feedback voltage V FB is small, so that the error amplifier EA is larger than the error signal ⁇ V generated by the feedback voltage V FB and the reference voltage V ref .
  • the frequency of the signal output from the oscillator 110 is increased, so that the period T of the signal received by the switch driving module 120 is decreased. Accordingly, the time t 2 of the discharge period is decreased. Therefore, the total discharge time is reduced, so that the output voltage Vcore at the output of the DC-DC converter rises, thereby starting to approach the expected voltage value.
  • FIG. 2 shows a specific example of the control circuit of FIG. 1.
  • the voltage dividing circuit 130 includes a first resistor R 1 and a second resistor R 2 ; one end of the first resistor R 1 is connected to one end of the second resistor R 2 and the first input of the multiplier 150 The other end of the first resistor R 1 is connected to the output of the DC-DC converter, and the other end of the second resistor R 2 is grounded.
  • At least one of the first resistor R 1 and the second resistor R 2 is a variable resistor.
  • the reference voltage V ref is greater than the feedback voltage V FB by adjusting the resistance of the variable resistor.
  • Switch drive module 120 includes a driver 122 (Driver), a DC - DC converter for controlling the charging of the energy storage module 140 of the first switch and the second switch S 1 is configured to discharge the energy storage module 140 control S 2 ; the output of the oscillator 110 is connected to the driver 122; the driver 122 is connected to the energy storage module 140 through the first switch S 1 and the second switch S 2 ; the energy storage module 140 is connected to the output of the DC-DC converter.
  • Driver Driver
  • DC - DC converter for controlling the charging of the energy storage module 140 of the first switch and the second switch S 1 is configured to discharge the energy storage module 140 control S 2 ;
  • the output of the oscillator 110 is connected to the driver 122;
  • the driver 122 is connected to the energy storage module 140 through the first switch S 1 and the second switch S 2 ; the energy storage module 140 is connected to the output of the DC-DC converter.
  • the driver 122 controls the conduction states of the first switch S 1 and the second switch S 2 according to the signal outputted by the output of the oscillator 110, wherein the first switch S 1 and the second switch S 2 are in an opposite conduction state, and the phase thereof The input is opposite to the output.
  • the signal output from the output of the oscillator 110 can be a rectangular wave signal.
  • the oscillator 110 can be a voltage controlled oscillator.
  • the energy storage module 140 includes an inductor L 1 and a capacitor C 1 ; one end of the inductor L 1 is connected to the first switch S 1 and the second switch S 2 ; the other end of the inductor L 1 and one end of the capacitor C 1 are connected to the direct current - the output of the DC converter; the other end of capacitor C 1 is grounded.
  • the first switch S 1 and the second switch S 2 are field effect transistors, respectively: a first field effect transistor Q 1 and a second field effect transistor Q 2 .
  • the driver 122 is connected to the output of the DC-DC converter through the first field effect transistor Q 1 and the second field effect transistor Q 2 ; the driver 122 is connected to the gate of the first field effect transistor Q 1 and the second field effect transistor Q 2 gate electrode; a source of a first field effect transistor Q 1 receives the input electrode of the DC voltage Vin, the first field effect transistor Q 1 and the drain of the transistor Q 2 is the drain of the second FET connected to the inductor L 1; The source Q 2 of the second field effect transistor is grounded.
  • Driver 122 receives the rectangular wave signal from the output of the oscillator 110, thereby driving the first field effect transistor Q 1 and a second field effect transistor Q 2 is turned on and off.
  • the first field effect transistor Q 1 is an insulated gate enhanced P-channel field effect transistor; the second field effect transistor Q 2 is an insulated gate depleted N-channel field effect transistor.
  • Fig. 3 shows a control circuit of another embodiment of the present invention.
  • the control circuit 100 of the DC-DC converter provided in this embodiment further includes a multiplier 150, and the first input terminal of the error amplifier EA receives the feedback voltage via the multiplier 150, as compared with the control circuit shown in FIG. V FB , wherein the first input of the multiplier 150 receives the feedback voltage V FB from the output voltage Vcore of the output of the DC-DC converter, the second input of the multiplier 150 receives the parameter compensation value A1; the output of the multiplier 150
  • the output voltage V A of the terminal is a multiplication value of the parameter compensation value A1 and the feedback voltage V FB .
  • the output of the different expected voltage values at the output of the DC-DC converter is achieved by a multiplier 150.
  • the parameter compensation value A1 is a compensation value of the expected voltage value at the output of the DC-DC converter, and is calculated by the voltage compensation module in the integrated circuit IC of the DC-DC converter.
  • the parameter compensation value A1 is less than one.
  • the parameter compensation value A1 is also different; the expected voltage value of the output of the DC-DC converter can be compensated by adjusting the parameter compensation value A1; the parameter compensation value A1 and The expected voltage value at the output of the DC-DC converter is inversely proportional.
  • the parameter value corresponding to the first expected voltage value at the output of the DC-DC converter is a (a ⁇ 1), then, if the second expected voltage value a first voltage is greater than the expected value, the second voltage value corresponding to the expected parameter compensation value a 1 (a 1 ⁇ 1) is less than a; if the expected second value of the first voltage is less than the desired voltage value, the second value corresponding to the desired voltage
  • the parameter compensation value a 1 (a 1 ⁇ 1) is greater than a.
  • the inverting input of the error amplifier EA receives the output voltage V A at the output of the multiplier 150; the non-inverting input of the error amplifier EA receives the reference voltage V ref ; the error signal ⁇ V at the output of the error amplifier EA is the reference voltage V ref and the multiplier 150
  • the input of the oscillator 110 receives the error signal ⁇ V, and the output of the oscillator 110 outputs the signal to the switch drive module 120 of the DC-DC converter.
  • the frequency of the signal at the output of the oscillator 110 is proportional to the error signal ⁇ V, that is, the larger the error signal ⁇ V is, the higher the frequency is, and the smaller the error signal ⁇ V is, the smaller the frequency is.
  • the response time can be effectively shortened, the transient becomes faster, and the stability of the system is significantly improved.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Dc-Dc Converters (AREA)

Abstract

一种直流-直流转换器的控制电路（100），包括误差放大器（EA）、振荡器（110）、乘法器（150）及分压电路（130）。乘法器的第一输入端接收直流-直流转换器的输出端的输出电压（Vcore）通过分压电路得到的反馈电压（V FB），乘法器的第二输入端接收参数补偿值（A1）；乘法器的输出端连接到误差放大器的第一输入端，误差放大器的第二输入端接收参考电压（Vref）；误差放大器的输出端连接到振荡器的输入端，以将误差放大器的输出（△V）提供给振荡器；振荡器的输出端将频率与误差放大器的输出成正比的信号输出到直流-直流转换器的开关驱动模块（120）。该控制电路有效缩短响应时间，瞬态变换快，提升系统的稳定性。

Description

直流-直流转换器的控制电路 技术领域
本发明总体说来涉及液晶显示器驱动电路的技术领域，更具体地讲，涉及一种直流-直流转换器的控制电路。
背景技术
直流-直流转换器(DC-DC converter)多为电流控制模式，所谓电流控制模式，就是在脉宽比较器的输入端将电流采样信号与误差放大器的输出信号进行比较，以此来控制输出脉冲的占空比，使输出的峰值电流跟随误差电压变化。目前，电流控制模式DC-DC转换器在采样输出电压信号的同时，电路同样对电感上的电流信号进行采集；跨导转换器(GM)接收输出电压的反馈电压与参考电压，并输出处理结果至比较器的反相输入端；电流侦测电路与三角波产生电路求和后的结果输出至比较器的同相输入端，比较器输出一个驱动信号用于控制功率管的开启与关断。因为跨导转换器需要环路补偿，导致输入和输出之间多一级相位延迟，导致响应时间变长，从而瞬态变慢，最终影响系统稳定性。
发明内容
本发明的目的在于提供一种新型的直流-直流转换器的控制电路，有效解决现有的电流控制模式直流-直流转换器因输入与输出之间多一级相位延迟导致的响应时间变长、瞬态变慢、影响系统稳定性的技术问题。
为实现上述发明目的，本发明提供一种直流-直流转换器的控制电路，包括：误差放大器、振荡器；所述误差放大器的第一输入端接收反馈电压，所述误差放大器的第二输入端接收参考电压；所述误差放大器的输出端连接到所述振荡器的输入端，以将所述误差放大器的输出提供给所述振荡器；所述振荡器的输出端将频率与所述误差放大器的输出成正比的信号输出到所述直流-直流转换器的开关驱动模块，以控制开关驱动模块的充放电时间。
还包括乘法器，所述误差放大器的第一输入端经由所述乘法器接收所述反馈电压，其中，所述乘法器的第一输入端接收所述反馈电压，所述乘法器的第二输入端接收参数补偿值；所述乘法器的输出端连接到所述误差放大器的第一输入端。
所述参数补偿值为所述直流-直流转换器的输出端的预期电压值的补偿值；所述参数补偿值由直流-直流转换器的集成电路中电压补偿模块计算得到；不同的直流-直流转换器的输出端的预期电压值对应的参数补偿值也不同，所述参数补偿值与所述预期电压值成反比。
所述参数补偿值小于1。
所述振荡器输出端的信号的频率与所述开关驱动模块的放电时间成反比。
所述直流-直流转换器的开关驱动模块通过储能模块连接到所述直流-直流转换器的输出端。
所述直流-直流转换器的控制电路还包括分压电路，所述反馈电压为直流-直流转换器输出端的输出电压通过分压电路得到的分压值。
所述参考电压大于所述反馈电压。
所述分压电路包括第一电阻器和第二电阻器；所述第一电阻器R1和第二电阻器R2中的至少一个为可变电阻器。
所述开关驱动模块包括驱动器、用于对所述直流-直流转换器的储能模块的充电进行控制的第一开关及用于对所述储能模块的放电进行控制的第二开关；所述驱动器根据振荡器的输出端输出的信号控制第一开关和第二开关的导通状态，其中，所述第一开关与第二开关的导通状态相反。
所述误差放大器的第一输入端为反相输入端，所述误差放大器的第二输入端为同相输入端。
所述频率与所述误差放大器的输出成正比的信号为矩形波信号。
本发明提供一种直流-直流转换器的控制电路，通过误差放大器与振荡器，使直流-直流转换器输出端的输出电压达到预期电压值并保持稳定；当需要改变直流-直流转换器的输出端的预期电压值时，通过设置乘法器接收反馈电压，然后将其与参数补偿值相乘后得到乘法器输出端的输出电压；误差放大器根据所 述乘法器输出端的输出电压与参考电压产生的放大信号，决定振荡器输出信号的频率，所述频率决定开关驱动模块的周期性工作状态，最终使所述直流-直流转换器输出端的输出电压达到改变后的预期电压值并保持稳定。所述控制电路有效缩短响应时间，从而瞬态变快，显著提升系统稳定性。
附图说明
图1示出本发明实施例的直流-直流转换器的控制电路的示意图。
图2示出图1的控制电路一个具体示例。
图3示出本发明的另一实施例的控制电路。
具体实施方式
图1示出本发明实施例的直流-直流转换器的控制电路的示意图。
参照图1，本发明的实施例中提出一种直流-直流转换器的控制电路100，包括：误差放大器EA、振荡器110。
误差放大器EA的反相输入端接收来自直流-直流转换器的输出端的输出电压Vcore的反馈电压VFB；误差放大器EA的同相输入端接收参考电压Vref，参考电压Vref小于直流-直流转换器的输出端的输出电压Vcore；误差放大器EA输出端的误差信号△V是参考电压Vref和反馈电压VFB的比较值的处理结果。参考电压Vref大于反馈电压VFB。
振荡器110的输入端接收误差信号△V，振荡器110的输出端将信号输出到直流-直流转换器的开关驱动模块120，以控制开关驱动模块120的充放电时间，进而对直流-直流转换器的输出端的输出电压Vcore进行调控，直至达到预期电压值并保持稳定。
振荡器110输出端的信号的频率与开关驱动模块120的放电时间成反比。
振荡器110输出端的信号的频率与误差信号△V成正比，即：误差信号△V越大对应振荡器输出端的信号的频率越高，误差信号△V越小对应振荡器输出端的信号的频率越小。
直流-直流转换器的控制电路100还包括分压电路130，反馈电压VFB为直 流-直流转换器的输出端的输出电压Vcore通过分压电路130得到的分压值。
开关驱动模块120接收输入的直流电压Vin；直流-直流转换器的开关驱动模块120通过储能模块140连接到直流-直流转换器的输出端。
本实施例提供的直流-直流转换器的控制电路100的工作过程为：
开关驱动模块120周期性地交替进行充电和放电。每个充电周期的时间t1是固定的，即，充电时间t1是固定的。而每个放电周期的时间t2根据振荡器输出端的信号的频率而变化。具体地说，放电周期的时间t2与振荡器110输出端的信号的频率成反比，即，振荡器110输出的信号的频率越大，放电周期的时间t2越小，从而整体上放电时间减少。
当直流-直流转换器输出端的输出电压Vcore小于预期电压值时，反馈电压VFB较小，从而误差放大器EA根据反馈电压VFB与参考电压Vref产生的误差信号△V较大。此时，振荡器110输出的信号的频率增大，从而开关驱动模块120接收的信号的周期T减小。相应地，放电周期的时间t2减小。因此，总的放电时间减小，使得直流-直流转换器输出端的输出电压Vcore升高，从而开始接近于预期电压值。
同理，当直流-直流转换器输出端的输出电压Vcore大于预期电压值时，反馈电压VFB较大，从而误差放大器EA产生的误差信号△V较小。此时，振荡器110输出的信号的频率减小，从而开关驱动模块120接收的信号的周期T增大。相应地，放电周期的时间t2增大。因此，总的放电时间增大，使直流-直流转换器输出端的输出电压Vcore下降，从而开始接近于预期电压值。如此多个周期的重复，直至直流-直流转换器输出端的输出电压Vcore达到输出的预期电压值并保持稳定。
图2示出图1的控制电路一个具体示例。
参照图2，分压电路130包括第一电阻器R1和第二电阻器R2；第一电阻器R1的一端连接到第二电阻器R2的一端及乘法器150的第一输入端；第一电阻器R1的另一端连接到直流-直流转换器的输出端，第二电阻器R2的另一端接地。
在一个示例中，第一电阻器R1和第二电阻器R2中的至少一个为可变电阻器。通过调整可变电阻器的阻值实现参考电压Vref大于反馈电压VFB。
开关驱动模块120包括驱动器122(Driver)、用于对直流-直流转换器的储 能模块140的充电进行控制的第一开关S1及用于对储能模块140的放电进行控制的第二开关S2；振荡器110的输出端连接到驱动器122；驱动器122通过第一开关S1和第二开关S2连接到储能模块140；储能模块140连接到直流-直流转换器的输出端。
驱动器122根据振荡器110的输出端输出的信号控制第一开关S1和第二开关S2的导通状态，其中，第一开关S1与第二开关S2的导通状态相反，其相位输入端和输出端相反。
振荡器110输出端输出的信号可为矩形波信号。
振荡器110可为压控振荡器。
储能模块140包括电感器L1和电容器C1；电感器L1的一端连接到第一开关S1和第二开关S2；电感器L1的另一端及电容器C1的一端连接到直流-直流转换器的输出端；电容器C1的另一端接地。
第一开关S1和第二开关S2均为场效应晶体管，分别为：第一场效应晶体管Q1和第二场效应晶体管Q2。驱动器122通过第一场效应晶体管Q1和第二场效应晶体管Q2连接到直流-直流转换器的输出端；驱动器122连接到第一场效应晶体管Q1的栅极、第二场效应晶体管Q2的栅极；第一场效应晶体管Q1的源极接收输入的直流电压Vin，第一场效应晶体管Q1的漏极与第二场效应晶体管Q2的漏极连接到电感器L1；第二场效应晶体管的源极Q2接地。
驱动器122接收来自振荡器110输出端的矩形波信号，进而驱动第一场效应晶体管Q1及第二场效应晶体管Q2的导通和截止。第一场效应晶体管Q1为绝缘栅增强型P沟道场效应晶体管；第二场效应晶体管Q2为绝缘栅耗尽型N沟道场效应晶体管。
图3示出本发明的另一实施例的控制电路。
参照图3，与图1所示的控制电路相比，本实施例提供的直流-直流转换器的控制电路100还包括乘法器150，误差放大器EA的第一输入端经由乘法器150接收反馈电压VFB，其中，乘法器150的第一输入端接收来自直流-直流转换器的输出端的输出电压Vcore的反馈电压VFB，乘法器150的第二输入端接收参数补偿值A1；乘法器150输出端的输出电压VA是参数补偿值A1和反馈电压VFB的乘法值。通过乘法器150实现直流-直流转换器输出端的不同预期电压值的输出。
参数补偿值A1为直流-直流转换器的输出端的预期电压值的补偿值，由直流-直流转换器的集成电路IC中的电压补偿模块计算得到。参数补偿值A1小于1。
针对不同的直流-直流转换器的输出端的预期电压值，参数补偿值A1也不同；可通过调整参数补偿值A1实现对直流-直流转换器的输出端的预期电压值进行补偿；参数补偿值A1与直流-直流转换器的输出端的预期电压值成反比，如：直流-直流转换器的输出端的第一预期电压值对应的参数补偿值是a(a＜1)，那么，若第二预期电压值大于第一预期电压值，则第二预期电压值对应的参数补偿值a1(a1＜1)小于a；若第二预期电压值小于第一预期电压值，则第二预期电压值对应的参数补偿值a1(a1＜1)大于a。
误差放大器EA的反相输入端接收乘法器150输出端的输出电压VA；误差放大器EA的同相输入端接收参考电压Vref；误差放大器EA输出端的误差信号△V是参考电压Vref和乘法器150输出端的输出电压VA的比较值的放大结果。
乘法器150的输出电压VA、反馈电压VFB、参考电压Vref、直流-直流转换器输出端的输出电压Vcore的关系为：VA≤VFB＜Vref＜Vcore。由此可见，误差放大器EA输出的误差信号△V为正。
振荡器110的输入端接收误差信号△V，振荡器110的输出端将信号输出到直流-直流转换器的开关驱动模块120。振荡器110输出端的信号的频率与误差信号△V成正比，即误差信号△V越大对应频率越高，误差信号△V越小对应频率越小。
采用上述根据本发明实施例的直流-直流转换器的控制电路，可以有效缩短响应时间，瞬态变快，显著提升系统稳定性。
上面已经结合具体实施例描述了本发明，但是本发明的实施不限于此。在本发明的精神和范围内，本领域技术人员可以进行各种修改和变型，这些修改和变型将落入权利要求限定的保护范围之内。

Claims (14)

  1. 一种直流-直流转换器的控制电路，其中，包括：误差放大器、振荡器；
    所述误差放大器的第一输入端接收反馈电压，所述误差放大器的第二输入端接收参考电压；
    所述误差放大器的输出端连接到所述振荡器的输入端，以将所述误差放大器的输出提供给所述振荡器；
    所述振荡器的输出端将频率与所述误差放大器的输出成正比的信号输出到所述直流-直流转换器的开关驱动模块，以控制所述开关驱动模块的充放电时间。
  2. 如权利要求1所述的直流-直流转换器的控制电路，其中，还包括乘法器，所述误差放大器的第一输入端经由所述乘法器接收所述反馈电压，其中，所述乘法器的第一输入端接收所述反馈电压，所述乘法器的第二输入端接收参数补偿值，所述乘法器的输出端连接到所述误差放大器的第一输入端。
  3. 如权利要求1所述的直流-直流转换器的控制电路，其中，还包括分压电路，所述反馈电压为所述直流-直流转换器的输出端的输出电压通过所述分压电路得到的分压值。
  4. 如权利要求2所述的直流-直流转换器的控制电路，其中，还包括分压电路，所述反馈电压为所述直流-直流转换器的输出端的输出电压通过所述分压电路得到的分压值。
  5. 如权利要求3所述的直流-直流转换器的控制电路，其中，所述参考电压大于所述反馈电压。
  6. 如权利要求4所述的直流-直流转换器的控制电路，其中，所述分压电路包括第一电阻器和第二电阻器。
  7. 如权利要求2所述的直流-直流转换器的控制电路，其中，所述参数补偿值为所述直流-直流转换器的输出端的预期电压值的补偿值，不同的预期电压值对应不同的参数补偿值，所述参数补偿值与所述预期电压值成反比。
  8. 如权利要求6所述的直流-直流转换器的控制电路，其中，所述参数补 偿值小于1。
  9. 如权利要求1所述的直流-直流转换器的控制电路，其中，所述开关驱动模块包括驱动器、用于对所述直流-直流转换器的储能模块的充电进行控制的第一开关及用于对所述储能模块的放电进行控制的第二开关；所述驱动器根据振荡器的输出端输出的信号控制第一开关和第二开关的导通状态，其中，所述第一开关与第二开关的导通状态相反。
  10. 如权利要求1所述的直流-直流转换器的控制电路，其中，所述振荡器输出端的信号的频率与所述开关驱动模块的放电时间成反比。
  11. 如权利要求1所述的直流-直流转换器的控制电路，其中，所述频率与所述误差放大器的输出成正比的信号为矩形波信号。
  12. 如权利要求2所述的直流-直流转换器的控制电路，其中，所述开关驱动模块包括驱动器、用于对所述直流-直流转换器的储能模块的充电进行控制的第一开关及用于对所述储能模块的放电进行控制的第二开关；所述驱动器根据振荡器的输出端输出的信号控制第一开关和第二开关的导通状态，其中，所述第一开关与第二开关的导通状态相反。
  13. 如权利要求2所述的直流-直流转换器的控制电路，其中，所述振荡器输出端的信号的频率与所述开关驱动模块的放电时间成反比。
  14. 如权利要求2所述的直流-直流转换器的控制电路，其中，所述频率与所述误差放大器的输出成正比的信号为矩形波信号。
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