CN102868288B - Switching regulation circuit, control circuit thereof and input voltage detecting method for switching regulation circuit - Google Patents
Switching regulation circuit, control circuit thereof and input voltage detecting method for switching regulation circuit Download PDFInfo
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- CN102868288B CN102868288B CN201110193957.9A CN201110193957A CN102868288B CN 102868288 B CN102868288 B CN 102868288B CN 201110193957 A CN201110193957 A CN 201110193957A CN 102868288 B CN102868288 B CN 102868288B
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Abstract
The invention provides a switching regulation circuit which comprises a power level circuit and a control circuit. The power level circuit comprises an upper bridge element and a lower bridge element which are coupled with each other so that input voltage is switched into output voltage, and intermediate voltage is generated at a node between the upper bridge element and the lower bridge element. The control circuit comprises an on-off operation circuit and a comparator, wherein the on-off operation circuit is used for operating the power level circuit and inputting a test signal to the upper bridge element, so that the upper bridge element is turned off after conducted for a period of time, and the comparator generates a ready signal indicating whether the input voltage is ready or not according to comparative results of the intermediate voltage and reference voltage after conduction of the upper bridge element is finished.
Description
Technical field
The present invention relates to and a kind ofly switch regulating circuit and control circuit thereof and for input voltage method for detecting wherein, refer to especially and a kind ofly more accurately can judge the switching regulating circuit whether power stage circuit power supply is ready and control circuit thereof and correlation technique.
Background technology
The effect switching regulating circuit input voltage is converted to output voltage (or output current), and usually controlled a power stage circuit to reach by a control chip, wherein, chip may receive different power supplys respectively from power stage circuit.And when the power supply of chip itself is ready and when starting to perform soft start (soft-start), must confirm that the power supply of power stage circuit is also ready.If chip just performs soft start when the power supply of power stage circuit is not ready, integrated circuit may be therefore impaired.
For the problems referred to above, the proposition of US patent number US7233131 patent is a kind of detects the whether ready switching regulating circuit of power stage circuit power supply.Please refer to Figure 1A, the switching regulating circuit 10 of prior art comprises: power stage circuit 11; And control chip 12, comprising: duplicate supply transducer 121; Current source 122, in order to carry out overcurrent protection; First comparator 123; Second comparator 124; 3rd comparator 125; First drives gate 126; And second drives gate 127.Control chip 12 produces test signal Vc1 and Vc2, make upper bridge element UG conducting (ON) of power stage circuit 11 and lower bridge element LG closes (OFF), so that by the dividing potential drop Vp and an overcurrent critical voltage Voc that compare intermediate voltage, the first comparator 122 can confirm that whether input voltage vin is ready when upper bridge element UG conducting.As shown in Figure 1B, when input voltage vin is ready, the intermediate voltage Vph of power stage circuit 11 equals input voltage vin, so that its dividing potential drop Vp is greater than reference voltage Voc; As shown in Figure 1 C, as the not ready (Vin=0 of input voltage vin, as shown in the figure) and upper bridge element UG conducting time, the intermediate voltage Vph of power stage circuit equals input voltage vin (equaling earth potential 0V), so that its dividing potential drop Vp is less than reference voltage Voc.Therefore, as suitably arranged detecting opportunity, such as, in figure shown in detection signal det, order being detected the relativeness of dividing potential drop Vp and overcurrent critical voltage Voc after bridge element UG conducting, can judge that whether input voltage vin is ready.
But the situation shown in Fig. 1 C is ideal situation, and in fact output voltage Vout must not equal earth potential 0V.Actual conditions as shown in figure ip, when input voltage vin is not ready, (Vin floats, as shown in the figure) and upper bridge element UG conducting time, the intermediate voltage Vph of power stage circuit equals output voltage Vout, if now because the output end vo ut of power stage circuit has remaining voltage, then the dividing potential drop Vp of intermediate voltage Vph is just likely greater than reference voltage Voc.Therefore, it is ready that prior art just can judge input voltage vin by accident in the middle of the situation shown in Fig. 1 D, so that control chip 12 still can perform soft start when the power supply of power stage circuit 11 is not ready, causes integrated circuit impaired.
In view of this, the present invention, namely for the deficiency of above-mentioned prior art, proposes a kind ofly to switch regulating circuit and control circuit thereof and for input voltage method for detecting wherein, whether the input voltage vin judging power stage circuit that can be more accurate is ready.
Summary of the invention
An object of the present invention is to overcome the deficiencies in the prior art and defect, proposes a kind of switching regulating circuit.
Another object of the present invention proposes a kind of control circuit switching regulating circuit.
Another object of the present invention proposes a kind of input voltage method for detecting for switching regulating circuit.
For reaching above-mentioned purpose, say with regard to one of them viewpoint, the invention provides a kind of switching regulating circuit, comprise: a power stage circuit, comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this; And a control circuit, this control circuit comprises: a switch operation circuit, in order to operate this power stage circuit, its input one test signal to bridge element on this, to make this was closed after bridge element conductive a period of time; And a comparator, after the bridge element conductive time terminates on this, according to the comparative result of this intermediate voltage and a reference voltage, produce a ready signal and represent that whether input voltage is ready.
Say with regard to another viewpoint, the invention provides a kind of control circuit switching regulating circuit, this switching regulating circuit comprises a power stage circuit, it comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this; The control circuit of this switching regulating circuit comprises: a switch operation circuit, in order to operate this power stage circuit, its input one test signal to bridge element on this, to make this was closed after bridge element conductive a period of time; And a comparator, after the bridge element conductive time terminates on this, according to the comparative result of this intermediate voltage and a reference voltage, produce a ready signal and represent that whether input voltage is ready.
In above-mentioned switching regulating circuit or control circuit, can further comprise a circuit overcurrent protection, and this comparator can comprise a diverter switch, make this comparator optionally receive this reference voltage or an overcurrent critical voltage, compare with this intermediate voltage; When this comparator selectivity receives this overcurrent critical voltage, the output of this comparator and this circuit overcurrent protection couple.
In above-mentioned switching regulating circuit or control circuit, this reference voltage should have following relation: 0 > reference voltage >-Vf, wherein Vf is the forward bias voltage drop of diode.
Say with regard to another viewpoint, the invention provides a kind of input voltage method for detecting, comprise: a power stage circuit is provided, comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this; Produce a test signal to bridge element on this, to make upper bridge element conductive a period of time; And after this ON time terminates, compare this intermediate voltage and a reference voltage, when this intermediate voltage is a negative voltage, and when its absolute value is greater than this reference voltage, produce a ready signal, in order to represent that this input voltage is ready.
Illustrate in detail below by specific embodiment, when the effect being easier to understand object of the present invention, technology contents, feature and reach.
Accompanying drawing explanation
Figure 1A is the schematic diagram of the switching regulating circuit of prior art;
Whether the input voltage that Figure 1B-1D display prior art cannot detect power stage circuit entirely truely is ready;
Fig. 2 A marks one embodiment of the present of invention;
Whether Fig. 2 B-2C correctly can to detect the input voltage of power stage circuit ready if showing the present invention;
Whether Fig. 3 A-3D how to detect input voltage ready if showing the present invention;
Fig. 4 marks an alternative embodiment of the invention;
Fig. 5 A-5H marks several embodiments of power stage circuit.
Symbol description in figure
10,20 suitching type regulating circuits
11,21 power stage circuits
12 control chips
121 duplicate supply inductors
122 current sources
123 first comparators
124 second comparators
125 the 3rd comparators
126,223 first drive gate
127,234 second drive gate
22 control circuits
221 switch operation circuit
222 comparators
225 circuit overcurrent protections
226,227 diverter switches
The upper bridge element of UG
Bridge element under LG
IL electric current
L inductance
The upper bridge node of Vug
Vcc1 chip input voltage
Vph intermediate voltage
The dividing potential drop of Vp intermediate voltage
Voc overcurrent critical voltage
Vref reference voltage
Vc1, Vc2 control signal
Vin input voltage
Vout output voltage
Embodiment
Please refer to Fig. 2 A, switching regulating circuit 20 of the present invention comprises: power stage circuit 21; And control circuit 22 (can with other circuit integrated become a control chip), comprising: switch operation circuit 221; Comparator 222; First drives lock 223; And second drives lock 224.The present invention is different from prior art part and is, the reference voltage setting position of comparator 222 is accurate and compare opportunity, all unlike the prior art; In detail, the present invention first produces test signal Vc1 by switch operation circuit 221, make upper bridge element UG conducting (ON) a period of time of power stage circuit 11, then when upper bridge element UG not conducting (OFF), compare intermediate voltage Vph (or dividing potential drop of intermediate voltage Vph) with a reference voltage Vref to confirm that whether input voltage vin is ready.Test signal Vc1 such as can reset signal (Power On Reset) according to startup during circuit start and produce.
Please refer to Fig. 3 A-3D, how to confirm that whether input voltage vin is ready to understand the present invention correctly, wherein, Fig. 3 A-3B shows the ready situation of voltage Vin, and Fig. 3 C-3D shows the not ready situation of voltage Vin.As shown in Figure 3A, if because test signal Vc1, during conducting, (above bridge element UG is nmos pass transistor is example to the ready and upper bridge element UG of input voltage vin, now go up bridge node Vug and be in high potential), input Vin by power stage circuit 21 is flowed to the output end vo ut of power stage circuit 21 by current i L, and now intermediate voltage Vph approximates input voltage vin; Then, as shown in Figure 3 B, after test signal Vc1 terminates, upper bridge element UG not conducting is (when upper bridge element UG is nmos pass transistor, upper bridge node Vug is in electronegative potential), now due to the effect of inductance L, current i L will through lower bridge element LG, (lower bridge element LG be such as the transistor of icon by earth potential, also can be diode), and then flow to output end vo ut, now intermediate voltage Vph and earthy difference at least equal the forward bias voltage drop Vf of diode parasitic in lower bridge element LG transistor.That is when input voltage is ready, after the testing procedure of Fig. 3 A-3B makes upper bridge element UG conducting close again, intermediate voltage Vph is by for a negative voltage and its absolute value at least equals the forward bias voltage drop Vf of diode.
Fig. 3 C-3D is presented at the situation that the not ready and output end vo ut of power stage circuit 21 of input voltage vin has remaining voltage.As shown in Figure 3 C, when upper bridge element UG switch because test signal Vc1 and conducting time, the output end vo ut by power stage circuit 21 is flowed to input Vin by current i L, and now intermediate voltage Vph approximates output voltage Vout; Then, as shown in Figure 3 D, after test signal Vc1 terminates, upper bridge element UG not conducting, now current i L still continues, by the diode of output end vo ut through upper bridge element UG transistor parasitic, to flow to input Vin.Therefore, intermediate voltage Vph at least equals the forward bias voltage drop Vf (Vph=Vin+Vf) that input voltage vin adds diode parasitic in bridge element UG transistor, because input voltage vin is at least zero and for negative value, therefore intermediate voltage Vph is on the occasion of (i.e. Vph > 0 >-Vf).
Again, when the not ready and output end vo ut of input voltage vin does not have remaining voltage, when upper bridge element UG switch because test signal Vc1 and conducting time, inductance two ends do not have voltage difference, therefore inductive current can not be produced, and after test signal Vc1 terminates, upper bridge element UG not conducting, now still there is no electric current, therefore intermediate voltage Vph is 0.
According to following manner, comprehensive above three kinds of situations, can judge that whether input voltage vin is ready:
Please later consult Fig. 2 A-2D, central display is all different from prior art due to detecting time point of the present invention and detecting mechanism, and whether the input voltage vin of detecting power stage circuit 21 that therefore can be more accurate is ready.In Fig. 2 A, Vref can be set to any-Vf of being greater than and be less than the value of 0; As shown in Figure 2 B, when input voltage vin is ready, if close again after upper bridge element UG conducting, intermediate voltage Vph will be less than or equal to-Vf, therefore after upper bridge element UG closes, detection signal det can be produced immediately or after postponing a bit of time, detection signal det enable under, intermediate voltage Vph compares with reference voltage Vref by comparator 222; As the mechanism described in Fig. 3 C-3D, if Vph≤-Vf, then represent input voltage vin ready.In addition, as shown in Figure 2 C, in input voltage vin not ready (Vin=0) and output end vo ut does not have remaining voltage (Vout=0), intermediate voltage Vph will equal 0 and be greater than reference voltage Vref, that is, Vph=0 >-Vf; Again as shown in Figure 2 D, in input voltage vin not ready (Vin floats) and output end vo ut has remaining voltage, intermediate voltage Vph will be greater than reference voltage Vref, that is, Vph > 0 >-Vf.Above as contrasted with Figure 1B-1D of prior art, can fully show, the present invention when the output end vo ut of power stage circuit 21 has remaining voltage, also can be correct to detect input voltage vin not ready, this is one of the present invention's reason being better than prior art.
Fig. 4 marks an alternative embodiment of the invention, and central control circuit 22 more can comprise a circuit overcurrent protection 225.In the diagram; comparator 222 also more can comprise diverter switch 226 and 227; make at comparator 222 except receiving except reference voltage Vref, also can receive an overcurrent critical voltage Voc, and its output sends switch operation circuit 221 or circuit overcurrent protection 225 to.When circuit start, intermediate voltage Vph compares with reference voltage Vref by comparator 222, judges that whether input voltage vin is ready; Once input voltage vin ready after, diverter switch 226 and 227 changes state, makes comparator 222 by intermediate voltage Vph compared with overcurrent critical voltage Voc, and exports comparative result to circuit overcurrent protection 225.In other words, in the present embodiment, circuit overcurrent protection 225 and switch operation circuit 221 can share same comparator 222.
Below for preferred embodiment, the present invention is described, just the above, be only and make those skilled in the art be easy to understand content of the present invention, be not used for limiting interest field of the present invention.Under same spirit of the present invention, those skilled in the art can think and various equivalence change.Such as, two interelements be directly connected of each embodiment icon, can plant and not affect other element of circuit major function; For another example, the transistor of the power switch in power stage circuit 11 can also can be PMOSFET for NMOSFET; And for example, power stage circuit of the present invention is not limited to synchronous buck converter, also can be analogized with the step-down of other synchronous versus asynchronous, boosting, type of voltage step-up/down converter, as shown in Fig. 5 A to 5H citing; For another example, intermediate voltage Vph and reference voltage Vref are compared, also can change into and the dividing potential drop of intermediate voltage Vph and the ratio value of reference voltage Vref are compared, or negative value is converted to absolute value to compare etc.Therefore, scope of the present invention should contain above-mentioned and other all equivalence change.
Claims (11)
1. switch a regulating circuit, it is characterized in that, comprise:
One power stage circuit, comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this; And
One control circuit, comprising:
One switch operation circuit, in order to operate this power stage circuit, its input one test signal to bridge element on this, to make this was closed after bridge element conductive a period of time; And
One comparator, after the bridge element conductive time terminates on this, according to the comparative result of this intermediate voltage and a reference voltage, produces a ready signal and represents that whether input voltage is ready.
2. switch regulating circuit as claimed in claim 1, wherein, this reference voltage has following relation: 0 > reference voltage > – Vf, wherein this lower bridge element is transistor or diode, instantly when bridge element is transistor, Vf is the forward bias voltage drop of diode parasitic in lower bridge element, and when bridge element is diode instantly, Vf is the forward bias voltage drop of this diode.
3. switch regulating circuit as claimed in claim 1, wherein, this comparator more comprises a diverter switch, makes this comparator optionally receive this reference voltage or an overcurrent critical voltage, compares with this intermediate voltage.
4. switch regulating circuit as claimed in claim 3, wherein, also include a circuit overcurrent protection, when this comparator selectivity receives this overcurrent critical voltage, the output of this comparator and this circuit overcurrent protection couple.
5. switch regulating circuit as claimed in claim 1, wherein, this power stage circuit comprises: decompression converting circuit, voltage up converting circuit or buck change-over circuit.
6. one kind switches the control circuit of regulating circuit, this switching regulating circuit comprises a power stage circuit, it comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this; It is characterized in that, the control circuit of this switching regulating circuit comprises:
One switch operation circuit, in order to operate this power stage circuit, its input one test signal to bridge element on this, to make this was closed after bridge element conductive a period of time; And
One comparator, after the bridge element conductive time terminates on this, according to the comparative result of this intermediate voltage and a reference voltage, produces a ready signal and represents that whether input voltage is ready.
7. the control circuit switching regulating circuit as claimed in claim 6, wherein, this reference voltage has following relation: 0 > reference voltage > – Vf, wherein this lower bridge element is transistor or diode, instantly when bridge element is transistor, Vf is the forward bias voltage drop of diode parasitic in lower bridge element, and when bridge element is diode instantly, Vf is the forward bias voltage drop of this diode.
8. the control circuit switching regulating circuit as claimed in claim 6, wherein, this comparator also comprises a diverter switch, makes this comparator optionally receive this reference voltage or an overcurrent critical voltage, compares with this intermediate voltage.
9. the control circuit switching regulating circuit as claimed in claim 8, wherein, also include a circuit overcurrent protection, when this comparator selectivity receives this overcurrent critical voltage, the output of this comparator and this circuit overcurrent protection couple.
10. an input voltage method for detecting, is characterized in that, comprises:
One power stage circuit is provided, comprise couple mutually one on bridge element and once bridge element, so that an input voltage is converted to an output voltage, and bridge element and the once interelement Nodes of bridge produce an intermediate voltage on this;
Produce a test signal to bridge element on this, to make upper bridge element conductive a period of time; And
After this ON time terminates, compare this intermediate voltage and a reference voltage, when this intermediate voltage is a negative voltage, and when its absolute value is greater than this reference voltage, produce a ready signal, in order to represent that this input voltage is ready.
11. input voltage method for detecting as claimed in claim 10, wherein, this reference voltage has following relation: 0 > reference voltage > – Vf, wherein this lower bridge element is transistor or diode, instantly when bridge element is transistor, Vf is the forward bias voltage drop of diode parasitic in lower bridge element, and when bridge element is diode instantly, Vf is the forward bias voltage drop of this diode.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110193957.9A CN102868288B (en) | 2011-07-07 | 2011-07-07 | Switching regulation circuit, control circuit thereof and input voltage detecting method for switching regulation circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110193957.9A CN102868288B (en) | 2011-07-07 | 2011-07-07 | Switching regulation circuit, control circuit thereof and input voltage detecting method for switching regulation circuit |
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| CN102868288A CN102868288A (en) | 2013-01-09 |
| CN102868288B true CN102868288B (en) | 2015-01-28 |
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| TWI586063B (en) * | 2015-12-17 | 2017-06-01 | 華碩電腦股份有限公司 | Power supply device |
| TWI627809B (en) * | 2017-01-25 | 2018-06-21 | 瑞昱半導體股份有限公司 | Electrostatic discharge protection circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1268801A (en) * | 1999-03-25 | 2000-10-04 | 新巨企业股份有限公司 | Power supply ready signal device of stable power supply equipment |
| US7741820B2 (en) * | 2008-01-25 | 2010-06-22 | Advanced Analog Technology, Inc. | Switching voltage regulator pulse width modulation controller and method |
| CN101939899A (en) * | 2007-12-21 | 2011-01-05 | L&L建筑公司 | The method and system of power governor/power amplifier switch control |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI285464B (en) * | 2004-07-02 | 2007-08-11 | Richtek Techohnology Corp | Circuit and method realizing multi-functional pin in pulse width modulation controller |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1268801A (en) * | 1999-03-25 | 2000-10-04 | 新巨企业股份有限公司 | Power supply ready signal device of stable power supply equipment |
| CN101939899A (en) * | 2007-12-21 | 2011-01-05 | L&L建筑公司 | The method and system of power governor/power amplifier switch control |
| US7741820B2 (en) * | 2008-01-25 | 2010-06-22 | Advanced Analog Technology, Inc. | Switching voltage regulator pulse width modulation controller and method |
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