CN111987905A - Load transient response circuit for DCDC converter in improved peak current mode - Google Patents
Load transient response circuit for DCDC converter in improved peak current mode Download PDFInfo
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- CN111987905A CN111987905A CN201910429615.9A CN201910429615A CN111987905A CN 111987905 A CN111987905 A CN 111987905A CN 201910429615 A CN201910429615 A CN 201910429615A CN 111987905 A CN111987905 A CN 111987905A
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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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The circuit is characterized by comprising a control logic circuit, a comparator and an oscillator, wherein the output end of the comparator is connected with the first input end of the control logic circuit, the positive input end of the comparator is connected with the output end of an error amplifier, the output end of the oscillator is connected with the second input end of the control logic circuit, an oscillator regulating circuit is arranged between the input end of the oscillator and the output end of the error amplifier, the negative input end of the error amplifier is connected with an output voltage end, and the positive input end of the error amplifier is connected with a reference voltage end.
Description
Technical Field
The invention relates to a load jump transient response technology of a peak current mode DCDC converter, in particular to a load transient response circuit of the peak current mode DCDC converter, which is characterized in that an oscillator regulating circuit is added between an output end of an error amplifier and an oscillator to change a switching frequency control signal output by the oscillator so as to improve the transient response of the DCDC converter during load jump, thereby better reducing the overshoot or undershoot amplitude during output voltage fluctuation.
Background
The DCDC converter is a circuit that converts one dc input voltage into another dc voltage of a different value and outputs the converted dc voltage. The peak current mode DCDC converter is a power conversion technology which is commonly used and is realized through current mode control, and the advantages of good dynamic performance, high output precision and the like are obtained through the combination of a current sampling circuit, an error amplifier, a PWM comparator and an oscillator. The inventor believes that if an oscillator regulating circuit is added between the output end of the error amplifier and the oscillator, the switching frequency control signal output by the oscillator can be changed, the switching frequency is reduced to restrain the output voltage overshoot amplitude when the output voltage is overshot due to the jump of the load from a heavy load to a light load, and the switching frequency is increased to restrain the output voltage undershoot amplitude when the output voltage is undershot due to the jump of the load from the light load to the heavy load, so that the transient response of the DCDC converter during the jump of the load is improved. In view of the above, the present inventors have completed the present invention.
Disclosure of Invention
Aiming at the defects or shortcomings in the prior art, the invention provides a circuit for improving the transient response of a load of a peak current mode DCDC converter, which improves the transient response of the DCDC converter during load jump by adding an oscillator regulating circuit between the output end of an error amplifier and an oscillator to change a switching frequency control signal output by the oscillator, thereby better reducing the overshoot or undershoot amplitude during output voltage fluctuation.
The technical scheme of the invention is as follows:
the DCDC converter load transient response circuit is characterized by comprising a control logic circuit, a comparator and an oscillator, wherein the output end of the comparator is connected with the first input end of the control logic circuit, the positive input end of the comparator is connected with the output end of an error amplifier, the output end of the oscillator is connected with the second input end of the control logic circuit, an oscillator adjusting circuit is arranged between the input end of the oscillator and the output end of the error amplifier, the negative input end of the error amplifier is connected with an output voltage end, and the positive input end of the error amplifier is connected with a reference voltage end.
The output signal of the error amplifier controls the oscillator adjusting circuit to generate an oscillator frequency control signal, the oscillator frequency control signal controls the oscillator to generate a switching frequency control signal, and the switching frequency control signal controls the output voltage through the control logic circuit so as to improve the transient response of the DCDC converter during load jump and reduce the overshoot or undershoot amplitude during fluctuation of the output voltage.
The comparator is a pulse width modulation comparator, the negative input end of the comparator is connected with the output end of the current sampling circuit, the input end of the current sampling circuit is connected with the high-side power tube, the high-side power tube is connected with the power supply voltage end, and the high-side power tube is connected with the output voltage end through a first inductor.
The first output end of the control logic circuit is connected with the high-side power tube, the second output end of the control logic circuit is connected with the low-side power tube, the low-side power tube is connected with a grounding end, an output voltage end is connected with the grounding end through a first capacitor, and a connection node is formed among the low-side power tube, the high-side power tube and the first inductor.
The oscillator adjusting circuit comprises an operational amplifier, a current source and a second capacitor, wherein the input end of the current source is connected with a power supply end, the output end of the current source is connected with one end of the second capacitor, the other end of the second capacitor is connected with a grounding end, the output end of the current source is connected with the input end of the oscillator, the output end of the operational amplifier is connected with the control end of the current source or the control end of the second capacitor, the positive input end of the operational amplifier is connected with a reference voltage end, and the negative input end of the operational amplifier is connected with the output end of the error amplifier.
The output end of the current source outputs an oscillator frequency control signal, the output end of the oscillator outputs a switching frequency control signal, the control logic circuit controls output voltage through the switching frequency, the negative input end of the error amplifier determines the output signal of the error amplifier through the difference between the output voltage and reference voltage or the difference between the feedback voltage of the output voltage and the reference voltage, and the output signal of the error amplifier is related to overshoot or undershoot of the output voltage caused by load jump.
The invention has the following technical effects: according to the circuit for improving the transient response of the load of the peak current mode DCDC converter, the oscillator adjusting circuit is introduced, so that the advantages of the peak current mode converter can be kept on the basis of not increasing peripheral components, the transient response of the load during jumping can be improved, and the circuit is very simple and effective to realize. The oscillator adjustment circuit may adjust the oscillator frequency based on the output of the error amplifier. When the load jumps from heavy load to light load, the output voltage can overshoot, the feedback voltage can also follow the overshoot, the output of the error amplifier can be lowered, the frequency of the oscillator is reduced, and finally the effect of restraining the overshoot amplitude of the output voltage is achieved by reducing the switching frequency. When the load jumps from light load to heavy load, the output voltage has undershoot, the feedback voltage can follow the undershoot, the output of the error amplifier can be increased, the frequency of the oscillator is increased, and finally the effect of restraining the undershoot amplitude of the output voltage is achieved by increasing the switching frequency.
Drawings
Fig. 1 is a schematic diagram of a circuit for improving the load transient response of a peak current mode DCDC converter according to the present invention.
Fig. 2 is a diagram showing the effect of the transient response of the load of the circuit implementing the invention.
Fig. 3 is a schematic diagram of an oscillator regulator circuit used in the practice of the present invention.
Fig. 4 is a schematic diagram of another oscillator adjustment circuit used in the practice of the present invention.
The reference numbers are listed below: vin-supply voltage or supply voltage terminal; vout-output voltage or output voltage terminal; vref-reference voltage or reference voltage terminal; GND-ground; VDD-Power supply terminal or supply voltage; i-a current source; l1 — first inductor; c1 — first capacitance; c2 — second capacitance; HSMp-high side power tube; LSmp-low side power tube; a Comp-comparator; ae-error amplifier; aop-operational amplifier; an OSC-oscillator; e1 — error amplifier output signal; f1-oscillator frequency control signal (or simply oscillator frequency control signal) output by the oscillator adjustment circuit; a switching frequency control signal (or simply referred to as a switching frequency control signal, and Fs may also refer to a switching frequency) output by the Fs-oscillator; PWM-pulse width modulation (pulse width modulation).
Detailed Description
The invention is described below with reference to the accompanying drawings (fig. 1-4).
Fig. 1 is a schematic diagram of a circuit for improving the load transient response of a peak current mode DCDC converter according to the present invention. Fig. 2 is a diagram showing the effect of the transient response of the load of the circuit implementing the invention. Fig. 3 is a schematic diagram of an oscillator regulator circuit used in the practice of the present invention. Fig. 4 is a schematic diagram of another oscillator adjustment circuit used in the practice of the present invention. As shown in fig. 1 to 4, a load transient response circuit for improving a peak current mode DCDC converter includes a control logic circuit, a comparator Comp and an oscillator OSC, wherein an output terminal of the comparator Comp is connected to a first input terminal of the control logic circuit, a positive input terminal (+) of the comparator Comp is connected to an output terminal of an error amplifier Ae, an output terminal of the oscillator OSC is connected to a second input terminal of the control logic circuit, an oscillator regulation circuit is disposed between the input terminal of the oscillator OSC and the output terminal of the error amplifier Ae, a negative input terminal (-) of the error amplifier is connected to an output voltage terminal Vout, and a positive input terminal (-) of the error amplifier is connected to a reference voltage terminal Vref. The error amplifier output signal E1 controls the oscillator regulating circuit to generate an oscillator frequency control signal F1, the oscillator frequency control signal F1 controls the oscillator OSC to generate a switching frequency control signal Fs, and the switching frequency control signal Fs controls the output voltage Vout through the control logic circuit so as to improve the transient response of the DCDC converter during load jump and reduce the overshoot or undershoot amplitude during fluctuation of the output voltage Vout.
The comparator Comp is a pulse width modulation comparator PWM Comp, a negative input (-) of the comparator Comp is connected to an output of a current sampling circuit, an input of the current sampling circuit is connected to a high-side power tube HSMp, the high-side power tube HSMp is connected to a supply voltage terminal Vin, and the high-side power tube HSMp is connected to the output voltage terminal Vout through a first inductor L1. The first output end of the control logic circuit is connected with the high-side power tube HSMp, the second output end of the control logic circuit is connected with the low-side power tube LSMp, the low-side power tube LSMp is connected with a ground terminal GND, the output voltage terminal Vout is connected with the ground terminal GND through a first capacitor C1, and a connection node is formed among the low-side power tube LSMp, the high-side power tube HSMp and the first inductor L1. The oscillator adjusting circuit comprises an operational amplifier Aop, a current source I and a second capacitor C2, wherein an input end of the current source I is connected with a power supply end VDD, an output end of the current source I is connected with one end of the second capacitor C2, the other end of the second capacitor C2 is connected with a ground end GND, an output end of the current source is connected with an input end of the oscillator OSC, an output end of the operational amplifier Aop is connected with a control end of the current source I or a control end of the second capacitor C2, a positive input end (+) of the operational amplifier Aop is connected with a reference voltage end Vref, and a negative input end (-) of the operational amplifier Aop is connected with an output end of the error amplifier Aop. The output end of the current source I outputs an oscillator frequency control signal F1, the output end of the oscillator OSC outputs a switching frequency control signal Fs, the control logic circuit controls an output voltage Vout through the switching frequency, the negative input end (-) of the error amplifier Ae determines an error amplifier output signal E1 through the difference between the output voltage Vout and a reference voltage Vref or the difference between the feedback voltage of the output voltage Vout and the reference voltage Vref, and the error amplifier output signal E1 is related to the overshoot or undershoot of the output voltage caused by load jump.
The oscillator adjustment circuit may adjust the oscillator frequency (Fs) based on the output (E1) of the error amplifier Ae. When the load jumps from a heavy load to a light load, the output voltage Vout will overshoot, the feedback voltage will also follow the overshoot, and the error amplifier output (E1) will become low, thereby reducing the frequency (Fs) of the oscillator OSC, and finally achieving the effect of suppressing the overshoot of the output voltage by reducing the switching frequency (see the right half of fig. 2). When the load jumps from light load to heavy load, the output voltage Vout has undershoot, the feedback voltage follows the undershoot, the error amplifier output (E1) becomes high, so as to increase the frequency (Fs) of the oscillator, and finally, the switching frequency is increased to achieve the effect of suppressing the undershoot amplitude of the output voltage (refer to the left half part of fig. 2). The significant feature of the present invention is the way to achieve improved transient response at load jump by changing the switching frequency, for which not only the oscillator regulation circuit is introduced in the peak current mode DCDC converter, but also the oscillator regulation circuit implementation is provided (refer to fig. 3 and 4).
It is pointed out here that the above description is helpful for the person skilled in the art to understand the invention, but does not limit the scope of protection of the invention. Any such equivalent, modified and/or simplified implementations as described above, e.g., implementations using other oscillator regulation circuits, etc., without departing from the spirit of the present invention, are intended to fall within the scope of the present invention.
Claims (6)
1. The DCDC converter load transient response circuit is characterized by comprising a control logic circuit, a comparator and an oscillator, wherein the output end of the comparator is connected with the first input end of the control logic circuit, the positive input end of the comparator is connected with the output end of an error amplifier, the output end of the oscillator is connected with the second input end of the control logic circuit, an oscillator adjusting circuit is arranged between the input end of the oscillator and the output end of the error amplifier, the negative input end of the error amplifier is connected with an output voltage end, and the positive input end of the error amplifier is connected with a reference voltage end.
2. The improved peak current mode DCDC converter load transient response circuit of claim 1, wherein an error amplifier output signal controls said oscillator adjustment circuit to generate an oscillator frequency control signal, said oscillator frequency control signal controls said oscillator to generate a switching frequency control signal, said switching frequency control signal controls an output voltage through said control logic circuit to improve a transient response of the DCDC converter at a load jump and reduce an overshoot or undershoot amplitude at a fluctuation of said output voltage.
3. The improved peak current mode DCDC converter load transient response circuit of claim 1, wherein said comparator is a pwm comparator, a negative input of said comparator is connected to an output of a current sampling circuit, an input of said current sampling circuit is connected to a high side power transistor, said high side power transistor is connected to a supply voltage terminal, and said high side power transistor is connected to said output voltage terminal through a first inductor.
4. The improved peak current mode DCDC converter load transient response circuit of claim 3, wherein a first output terminal of the control logic circuit is connected to the high side power transistor, a second output terminal of the control logic circuit is connected to a low side power transistor, the low side power transistor is connected to a ground terminal, the output voltage terminal is connected to the ground terminal through a first capacitor, and a connection node is formed among the low side power transistor, the high side power transistor and the first inductor.
5. The improved peak current mode DCDC converter load transient response circuit of claim 1, wherein said oscillator regulation circuit comprises an operational amplifier, a current source and a second capacitor, an input terminal of said current source is connected to a power supply terminal, an output terminal of said current source is connected to one terminal of said second capacitor, another terminal of said second capacitor is connected to a ground terminal, an output terminal of said current source is connected to an input terminal of said oscillator, an output terminal of said operational amplifier is connected to a control terminal of said current source or to a control terminal of said second capacitor, a positive input terminal of said operational amplifier is connected to a reference voltage terminal, and a negative input terminal of said operational amplifier is connected to an output terminal of said error amplifier.
6. The improved peak current mode DCDC converter load transient response circuit of claim 5, wherein said current source output terminal outputs an oscillator frequency control signal, said oscillator output terminal outputs a switching frequency control signal, said control logic circuit controls an output voltage by switching frequency, said error amplifier negative input terminal determines an error amplifier output signal by a difference between the output voltage and a reference voltage or a difference between a feedback voltage of the output voltage and the reference voltage, said error amplifier output signal being related to an overshoot or undershoot of the output voltage caused by a load jump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910429615.9A CN111987905B (en) | 2019-05-22 | 2019-05-22 | Load transient response circuit for DCDC converter in improved peak current mode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910429615.9A CN111987905B (en) | 2019-05-22 | 2019-05-22 | Load transient response circuit for DCDC converter in improved peak current mode |
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| Publication Number | Publication Date |
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| CN111987905A true CN111987905A (en) | 2020-11-24 |
| CN111987905B CN111987905B (en) | 2022-04-12 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201910429615.9A Active CN111987905B (en) | 2019-05-22 | 2019-05-22 | Load transient response circuit for DCDC converter in improved peak current mode |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6366070B1 (en) * | 2001-07-12 | 2002-04-02 | Analog Devices, Inc. | Switching voltage regulator with dual modulation control scheme |
| CN101036094A (en) * | 2004-02-19 | 2007-09-12 | 国际整流器公司 | DC-DC regulator with switching frequency responsive to load |
| US20080024104A1 (en) * | 2006-07-25 | 2008-01-31 | Fuji Electric Device Technology Co., Ltd. | DC-DC converter |
| CN101924469A (en) * | 2010-08-06 | 2010-12-22 | 东南大学 | Switching power supply with fast transient response |
| CN103532347A (en) * | 2013-10-09 | 2014-01-22 | 无锡华润矽科微电子有限公司 | PWM (pulse width modulation)-type switching power circuit |
-
2019
- 2019-05-22 CN CN201910429615.9A patent/CN111987905B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6366070B1 (en) * | 2001-07-12 | 2002-04-02 | Analog Devices, Inc. | Switching voltage regulator with dual modulation control scheme |
| CN101036094A (en) * | 2004-02-19 | 2007-09-12 | 国际整流器公司 | DC-DC regulator with switching frequency responsive to load |
| US20080024104A1 (en) * | 2006-07-25 | 2008-01-31 | Fuji Electric Device Technology Co., Ltd. | DC-DC converter |
| CN101924469A (en) * | 2010-08-06 | 2010-12-22 | 东南大学 | Switching power supply with fast transient response |
| CN103532347A (en) * | 2013-10-09 | 2014-01-22 | 无锡华润矽科微电子有限公司 | PWM (pulse width modulation)-type switching power circuit |
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| CN111987905B (en) | 2022-04-12 |
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