CN207234669U - The zero current detection and error of a kind of DC to DC converter eliminate circuit automatically - Google Patents
The zero current detection and error of a kind of DC to DC converter eliminate circuit automatically Download PDFInfo
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- CN207234669U CN207234669U CN201721233611.6U CN201721233611U CN207234669U CN 207234669 U CN207234669 U CN 207234669U CN 201721233611 U CN201721233611 U CN 201721233611U CN 207234669 U CN207234669 U CN 207234669U
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Abstract
Zero current detection and error the utility model discloses a kind of DC to DC converter eliminate circuit automatically, including afterflow power tube, comparator, control logic circuit, power circuit and error eliminate circuit automatically, inductance connection in the drain electrode and DC to DC converter of afterflow power tube, error eliminates circuit automatically includes error measuring circuitry, error storage circuit and error compensation circuit, two input terminals of error measuring circuitry are connected with the source electrode of afterflow power tube and drain electrode respectively, two output terminals of error measuring circuitry are connected with the positive terminal and end of oppisite phase of comparator respectively；The input terminal connection error measuring circuitry of error storage circuit, the input terminal of the output terminal connection error compensation circuit of error storage circuit, two output terminals of error compensation circuit are connected with the positive terminal and end of oppisite phase of comparator respectively, the second Enable Pin connection error measuring circuitry of control logic circuit.The utility model can lift DC DC zero current detection precision, reduce the loss in efficiency that zero current detection error band comes, and lift the transfer efficiency of DC DC.
Description
Technical field
It the utility model is related to zero current detection technical field, and in particular to a kind of zero electricity of DC-to-dc converter
Stream detection and error eliminate circuit automatically.
Background technology
DC-to-dc converter (DC-DC) is in heavy duty, in inductor current continuous mode (CCM).But gently bearing
During load, duty cycle declines, so as to be in discontinuous mode (DCM).Inductive current is counter in order to prevent fills, so as to reduce light
Transfer efficiency during load, DC-DC generally has inductance zero current detecting circuit, as shown in Figure 1, method is examined with comparator
Source electrode and the drain electrode both ends pressure drop of afterflow power tube are surveyed, once finding that the both ends pressure drop of power tube source drops to zero, that is, thinks electric current
It is zero, turns off afterflow power tube at once.But due to IC manufacturing, there is the mismatch between device, comparator to deposit
At input offset voltage (offset), so as to cause zero current detection, there are deviation.As shown in Figures 2 and 3, wherein, from Fig. 3
Oscillogram above can be seen that when input offset voltage (offset) is just, to cause to turn off in advance, cause current waist, band
Carry out loss in efficiency, in Fig. 3 below oscillogram can be seen that when input offset voltage (offset) be negative, cause to turn off hysteresis,
Cause, from load back suction electric current, to cause loss in efficiency.Meanwhile with the continuous lifting of electronic equipment performance, processor power consumption is not
Disconnected increase, DC-DC supply currents ability constantly increase therewith, and DC-DC single channel load capacity rises to 5A, so that DC-DC
Power tube internal resistance also constantly decline, be reduced to 10mohm ranks, therefore the pressure drop of power tube both ends is also less and less.If compare
Device input offset voltage (offset) is 5mV, then the error of zero current detection is 500mA, thus DC-DC can be caused gently to load
Decrease in efficiency.Simultaneously as the device mismatch of manufacturing process is discrete, therefore the input offset voltage of comparator is also
Discrete, the inconsistency in production process can be caused, i.e. the deviation per chips is all different.
Utility model content
The purpose of this utility model is to provide a kind of zero current detecting circuit for DC-to-dc converter, realizes
The accurate inductance zero current detection of the low internal resistance DC-DC of high current.
To achieve the above object, the technical solution of the utility model is：
The zero current detection and error of a kind of DC-to-dc converter eliminate circuit automatically, including afterflow power tube, compare
Device, control logic circuit and power circuit, wherein, it is used to transmit in the drain electrode and DC-to-dc converter of afterflow power tube
With the inductance connection of storage energy, the drain electrode of afterflow power tube and source electrode are also respectively connected with the positive terminal and end of oppisite phase of comparator,
The input terminal of the output terminal connection control logic circuit of comparator, the input of the output terminal connection drive circuit of control logic circuit
End, the grid of the output terminal connection afterflow power tube of drive circuit, the first Enable Pin connection comparator of control logic circuit, its
It is characterized in that：
Further include error and eliminate circuit automatically, the error eliminates circuit automatically includes error measuring circuitry, error storage
Circuit and error compensation circuit；
The error measuring circuitry includes two input terminals, the source electrode with afterflow power tube and the drain electrode respectively of two input terminals
Connection, for gathering the voltage of the afterflow power tube source electrode and drain electrode, error measuring circuitry further includes two output terminals, and two defeated
Outlet is connected with the positive terminal and end of oppisite phase of the comparator respectively；
The input terminal of the error storage circuit connects the error measuring circuitry, the output terminal of the error storage circuit
The input terminal of error compensation circuit is connected, error compensation circuit includes two output terminals, respectively with the positive terminal of comparator and instead
Phase end connects, for the afterflow power tube source electrode measured according to the error measuring circuitry and the voltage difference of drain electrode in comparator
Two input terminals carry out corresponding compensation input；
The control logic circuit further includes the second Enable Pin, the second Enable Pin connection error measuring circuitry or error compensation
Circuit, for controlling error to eliminate circuit operation automatically.
The error measuring circuitry includes SAR ADC converter, and the error storage circuit is stored including error
Register, the error compensation circuit include DAC converter.
The error measuring circuitry includes capacitance, first switch and second switch, and the capacitance first end passes through described
One switch be connected to afterflow power tube drain electrode and comparator positive terminal connecting line on, the second end of the capacitance with it is described
The negative phase end connection of comparator, the second end of the capacitance are also connected by the output terminal of the second switch and comparator；
The error compensation circuit includes the 3rd switch and the capacitance, and the capacitance first end passes through the described 3rd switch
It is connected on the source electrode of afterflow power tube, the second end of the capacitance is connected with the negative phase end of the comparator；
The error storage circuit includes error sampling and keeps logic module, which keeps logic module to include three
A control terminal for connecting and controlling respectively it to open and close with first switch, second switch and the 3rd switch, passes through the error
Sampling is kept for three of logic module control switch on-off, and makes the voltage error information that error measuring circuitry measures in the electricity
Certain time is kept in appearance.
The beneficial effects of the utility model are：This circuit possesses error automatic eliminating function, can automotive resistance integrate electricity
The input offset voltage for the comparator that road manufacture mismatch is brought, so that the error of zero current detection be greatly reduced, makes the electricity of inductance zero
Stream detection error drops to 50mA or so from 500mA ranks, can lift DC-DC zero current detection precision, reduces zero current inspection
Survey the loss in efficiency of error band, can be lifted DC-DC under light load (10mA~100mA) transfer efficiency, it might even be possible to
Buck converter (BUCK DCDC) transfer efficiency under light load is set to can also remain at 90%, so as to lift electronic equipment
Service time of battery, meanwhile, the uniformity of chip when can improve volume production.
Brief description of the drawings
Fig. 1 is traditional zero current detecting circuit schematic diagram；
Fig. 2 is traditional zero current detecting circuit operation principle schematic diagram；
Fig. 3 is power loss schematic diagram caused by traditional zero current detecting circuit error；
Fig. 4 is the zero current detecting circuit functional block diagram that the utility model possesses error automatic eliminating function；
Fig. 5 eliminates schematic block circuit diagram automatically for the utility model error；
Fig. 6 is the functional block diagram that the utility model error eliminates circuit embodiments one automatically；
Fig. 7 is the functional block diagram that the utility model error eliminates circuit embodiments two automatically；
Fig. 8 is the switching capacity offset voltage sample-and-hold circuit that the utility model error eliminates circuit embodiments two automatically
Schematic diagram；
Fig. 9 is the error compensation procedure circuit diagram that the utility model error eliminates circuit embodiments two automatically.
Embodiment
Carried out below with reference to the technique effect of the design of embodiment and attached drawing to the utility model, concrete structure and generation
Clearly and completely describe, to be completely understood by the purpose of this utility model, feature and effect.Obviously, described embodiment
It is the part of the embodiment of the utility model, rather than whole embodiments, those skilled in the art are not paying creative labor
The other embodiment obtained on the premise of dynamic, belongs to the scope of the utility model protection.
As shown in Figure 4 and Figure 5, a kind of zero current detection of DC-to-dc converter and error eliminate circuit automatically, including
Afterflow power tube, comparator, control logic circuit and power circuit, wherein, drain electrode and the DC-DC of afterflow power tube are changed
The inductance connection for being used for transmission and storage energy in device, the drain electrode of afterflow power tube and source electrode are being also respectively connected with comparator just
Phase end and end of oppisite phase, the input terminal of the output terminal connection control logic circuit of comparator, the output terminal connection of control logic circuit
The input terminal of drive circuit, the grid of the output terminal connection afterflow power tube of drive circuit, the first of control logic circuit are enabled
End connection comparator, further includes error and eliminates circuit automatically, error eliminates circuit automatically includes error measuring circuitry, error storage
Circuit and error compensation circuit.
Error measuring circuitry includes two input terminals, and two input terminals connect with the source electrode of afterflow power tube and drain electrode respectively
Connect, for gathering the voltage of the afterflow power tube source electrode and drain electrode, error measuring circuitry further includes two output terminals, error measure
The voltage of two output terminals output of circuit corresponds to the afterflow power tube source electrode of error measuring circuitry measurement and the electricity of drain electrode respectively
Pressure, two output terminals are connected with the positive terminal and end of oppisite phase of comparator respectively；The input terminal connection error of error storage circuit is surveyed
Circuit is measured, for the afterflow power tube source electrode of memory error measuring circuit measurement and the voltage and voltage difference of drain electrode.
The input terminal of the output terminal connection error compensation circuit of error storage circuit, error compensation circuit include two outputs
End, is connected with the positive terminal and end of oppisite phase of comparator, for the afterflow power tube source electrode measured according to error measuring circuitry respectively
With the voltage difference of drain electrode corresponding compensation input is carried out in two input terminals of comparator.
The control logic circuit further includes the second Enable Pin, the second Enable Pin connection error measuring circuitry or error compensation
Circuit, for controlling error to eliminate circuit operation automatically.
The error measuring circuitry in circuit, error storage circuit and error compensation circuit is eliminated automatically to error below to enumerate
Two specific embodiments are illustrated：
Embodiment one：As shown in fig. 6, error measuring circuitry uses SAR ADC converter, error storage circuit is adopted
With error storage register, error compensation circuit uses DAC converter.
Assuming that comparator error range is ± 10mV scopes, then error measuring circuitry can be by the Approach by inchmeal of a 6bit
Type ADC converters realize that ADC detection least units are 0.5mV, then can realize the error measure scope of ± 16mV, while can
Controlling comparator input offset voltage in the range of 0.5mV.SAR ADC converter measures the mistake of comparator first
Difference data, error measurement are stored in error storage register.Then according to the mistake of the preservation of error storage register
Difference, is superimposed an offset in comparator input terminal using a DAC converter, offsets the input offset voltage of comparator.
All include a DAC due to general in SAR ADC converter, it is electric that the DAC in circuit can be multiplexed error measure
The DAC in SAR ADC in road, can achieve the purpose that, which reduces circuit complexity, reduces chip cost.
Embodiment two：As shown in fig. 7, error measuring circuitry includes capacitance, first switch and second switch, capacitance first end
Be connected to by first switch on the connecting line of the drain electrode of afterflow power tube and the positive terminal of comparator, the second end of capacitance with than
Negative phase end compared with device connects, and the second end of capacitance is also connected by the output terminal of second switch and comparator；Error compensation circuit
Including the 3rd switch and capacitance, error measuring circuitry and error compensation circuit use same capacitance, and capacitance first end passes through the
Three switches are connected on the source electrode of afterflow power tube, and the second end of capacitance and the negative phase end of comparator connect；Error storage circuit
Logic module is kept using error sampling, which keeps logic module to be opened respectively with first switch, second including three
Close and the 3rd switchs the control terminal for connecting and controlling its unlatching and closure, the three of logic module control are kept by the error sampling
It is a to switch on-off, the voltage error information that error measuring circuitry measures is kept certain time in capacitance.Error concealment
Cheng Wei：In error-detecting cycle and storage cycle, S1 is turned on S2, and S3 is disconnected.Comparator output terminal and negative input end are short at this time
Connect, that is, be connected to unity gain buffer, as shown in Figure 8.The pressure difference VOFF of positive-negative input end is the defeated of comparator at this time
Enter offset voltage, therefore error voltage VOFF is sampled using capacitance C1 and is kept.After completing error-detecting and preserving, into just
In the normal zero passage detection cycle, S1 and S2 is disconnected at this time, while S3 is turned on, as shown in Figure 9.The error voltage VOFF that C1 is preserved at this time
Automatically it has been added in input signal, has achieveed the purpose that automatic elimination error.
It is the preferred embodiment of the utility model it should be noted that described above, the utility model not office
It is limited to the above embodiment, as long as it reaches the technique effect of the utility model with identical means, it is new should all belongs to this practicality
The protection domain of type.
Claims (3)
1. the zero current detection and error of a kind of DC-to-dc converter eliminate circuit automatically, including afterflow power tube, compare
Device, control logic circuit and power circuit, wherein, the inductance connection in the drain electrode and DC-to-dc converter of afterflow power tube,
The drain electrode of afterflow power tube and source electrode are also respectively connected with the positive terminal and end of oppisite phase of comparator, the output terminal connection control of comparator
The input terminal of logic circuit, the input terminal of the output terminal connection drive circuit of control logic circuit, the output terminal of drive circuit connect
Continue and flow the grid of power tube, the first Enable Pin connection comparator of control logic circuit, it is characterised in that：
Further include error and eliminate circuit automatically, the error eliminates circuit automatically includes error measuring circuitry, error storage circuit
And error compensation circuit；
The error measuring circuitry includes two input terminals, and two input terminals connect with the source electrode of afterflow power tube and drain electrode respectively
Connect, for gathering the voltage of the afterflow power tube source electrode and drain electrode, error measuring circuitry further includes two output terminals, two outputs
End is connected with the positive terminal and end of oppisite phase of the comparator respectively；
The input terminal of the error storage circuit connects the error measuring circuitry, the output terminal connection of the error storage circuit
The input terminal of error compensation circuit, error compensation circuit include two output terminals, respectively with the positive terminal and end of oppisite phase of comparator
Connection, for the afterflow power tube source electrode that measure according to the error measuring circuitry and the voltage difference to drain at two of comparator
Input terminal carries out corresponding compensation input；
The control logic circuit further includes the second Enable Pin, the second Enable Pin connection error measuring circuitry or error compensation electricity
Road, for controlling error to eliminate circuit operation automatically.
2. the zero current detection and error of DC-to-dc converter as claimed in claim 1 eliminate circuit automatically, its feature exists
In：The error measuring circuitry includes SAR ADC converter, and the error storage circuit includes error storage deposit
Device, the error compensation circuit include DAC converter.
3. the zero current detection and error of DC-to-dc converter as claimed in claim 1 eliminate circuit automatically, its feature exists
In：
The error measuring circuitry includes capacitance, first switch and second switch, and the capacitance first end is opened by described first
Connection is connected on the connecting line of the drain electrode of afterflow power tube and the positive terminal of comparator, the second end of the capacitance and the comparison
The negative phase end connection of device, the second end of the capacitance are also connected by the output terminal of the second switch and comparator；
The error compensation circuit includes the 3rd switch and the capacitance, and the capacitance first end is connected by the described 3rd switch
On the source electrode of afterflow power tube, the second end of the capacitance is connected with the negative phase end of the comparator；
The error storage circuit includes error sampling and keeps logic module, which keeps logic module to include three points
The control terminal for not connecting and controlling it to open and close with first switch, second switch and the 3rd switch, passes through the error sampling
Kept for three of logic module control switch on-off, make the voltage error information that error measuring circuitry measures in the capacitance
Kept for certain time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721233611.6U CN207234669U (en) | 2017-09-25 | 2017-09-25 | The zero current detection and error of a kind of DC to DC converter eliminate circuit automatically |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721233611.6U CN207234669U (en) | 2017-09-25 | 2017-09-25 | The zero current detection and error of a kind of DC to DC converter eliminate circuit automatically |
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| Publication Number | Publication Date |
|---|---|
| CN207234669U true CN207234669U (en) | 2018-04-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201721233611.6U Active CN207234669U (en) | 2017-09-25 | 2017-09-25 | The zero current detection and error of a kind of DC to DC converter eliminate circuit automatically |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108387771A (en) * | 2018-03-13 | 2018-08-10 | 东莞赛微微电子有限公司 | A kind of reverse current detecting system |
| CN116068259A (en) * | 2023-02-22 | 2023-05-05 | 无锡力芯微电子股份有限公司 | High-precision zero current detection circuit and method |
-
2017
- 2017-09-25 CN CN201721233611.6U patent/CN207234669U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108387771A (en) * | 2018-03-13 | 2018-08-10 | 东莞赛微微电子有限公司 | A kind of reverse current detecting system |
| CN116068259A (en) * | 2023-02-22 | 2023-05-05 | 无锡力芯微电子股份有限公司 | High-precision zero current detection circuit and method |
| CN116068259B (en) * | 2023-02-22 | 2024-01-02 | 无锡力芯微电子股份有限公司 | High-precision zero current detection circuit and method |
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| CP03 | Change of name, title or address |
Address after: 519000 room 1401-1405, building 4, No. 101, University Road, Tangjiawan Town, Xiangzhou District, Zhuhai City, Guangdong Province Patentee after: Zhuhai Zhirong Technology Co.,Ltd. Address before: 519000 a401, Tsinghua Science Park, No. 101, University Road, Tangjiawan, high tech Zone, Zhuhai, Guangdong Patentee before: ZHUHAI SMART WARE TECHNOLOGY CO.,LTD. |