CN101762734B - Output voltage detection circuit and switching power supply - Google Patents
Output voltage detection circuit and switching power supply Download PDFInfo
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- CN101762734B CN101762734B CN200810184922A CN200810184922A CN101762734B CN 101762734 B CN101762734 B CN 101762734B CN 200810184922 A CN200810184922 A CN 200810184922A CN 200810184922 A CN200810184922 A CN 200810184922A CN 101762734 B CN101762734 B CN 101762734B
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Abstract
The invention discloses an output voltage detection circuit and a switching power supply, wherein the output voltage detection circuit can correspondingly generate test signals according to the compensation voltage and output voltage generated by the conductive layout through which the current flows; as the compensation voltage of the conductive layout is utilized to compensate the conduction voltage drop of the power supply wire, the test signals can reflect the conduction voltage drop of the power supply wire, relatively, the changing amount of the voltage at the system circuit power supply end sent to the system circuit is smaller, and the voltage regulation rate is smaller. The invention has lower cost and smaller volume and has no need to connect two additional detection wires with the power supply end of the system circuit, therefore the total wire material is not led to be thicker, and the invention is applicable to external or portable power supply with total wire material size limit.
Description
Technical field
The present invention relates to a kind of testing circuit and power supply unit, relate in particular to a kind of the have output voltage detecting circuit of voltage difference compensation and the switched power supplier (switching power supply) of this output voltage detecting circuit of tool.
Background technology
In recent years along with the progress of science and technology; Electronic product with difference in functionality of all kinds is developed out gradually; These electronic products with difference in functionality of all kinds have not only satisfied the people of various different demands, more incorporate everyone daily life, and it is more convenient to make people live.
Because the electronic product of these difference in functionalitys of all kinds according to the characteristic of electronic product, is selected suitable electronic package for use and formed, therefore, the supply voltage that the circuit system of each electronic product needs is not quite similar.In order to provide suitable supply voltage to make its normal operation to the circuit system of electronic product; Electronic product need produce the required supply voltage of circuit system by power supply unit; For example; Power supply unit can produce the output voltage of 12 volts (V), and by power lead the output voltage that power supply unit produces is sent to electronic product.
Wherein, output voltage can change along with the power consumption of circuit system, causes the magnitude of voltage of output voltage to alter a great deal.In order to reduce the magnitude of voltage variable quantity of output voltage, power supply unit can have output voltage detecting circuit, in order to detect output voltage and to produce detection signal according to output voltage, the magnitude of voltage variable quantity of output voltage is reduced.
Yet; The output current of power supply unit can make the power lead that is connected between circuit system and the power supply unit produce the conduction pressure drop; Make the magnitude of voltage of the circuit system power end voltage that circuit system receives be not equal to the magnitude of voltage of output voltage, though the magnitude of voltage variable quantity of output voltage reduces because of testing circuit; But; The magnitude of voltage of circuit system power end voltage still can change along with the power consumption of circuit system, sees through power delivery, makes that the magnitude of voltage variable quantity of circuit system power end voltage is very big; And the voltage difference between the magnitude of voltage of the power consumption of the magnitude of voltage of the circuit system power end voltage of the power consumption of circuit system when maximum and circuit system circuit system power end voltage hour is also higher, makes the voltage regulation factor (Voltage Regulation) of circuit system power end voltage higher relatively.
In the magnitude of voltage of some traditional output voltage detecting circuits for the circuit system power end voltage of the conduction pressure drop affects that detection signal can be reflected receive power lead; Need to use extra load detecting circuit to cooperate; Not only make the complicated circuit of output voltage detecting circuit and power supply unit, and manufacturing cost is higher relatively, because; Need extra load detecting circuit to cooperate, make that relatively the volume of power supply unit is bigger.
In two detection lines that are connected in the circuit system power end of some conventional power source supplies extra increases of meeting; Make traditional output voltage detecting circuit can be directly produce detection signal according to the magnitude of voltage of circuit system power end voltage; Because power supply unit needs extra increase detection line, cost is increased; Also make the whole wire rod that is connected between power supply unit and the circuit system become thicker, can't be applied to circumscribed or portable power supply device that some limit whole wire rod size.
From the above; The tradition output voltage detecting circuit only produces detection signal according to output voltage; So detection signal can't reflect the magnitude of voltage of the circuit system power end voltage of the conduction pressure drop affects that receives power lead; It is bigger relatively to make the conventional power source supply be sent to the magnitude of voltage variable quantity of circuit system power end voltage of circuit system by power lead, and voltage regulation factor is higher.
Therefore, how to develop a kind of output voltage detecting circuit and switched power supplier that improves above-mentioned known technology defective, real problem for the correlative technology field person solution that presses at present.
Summary of the invention
Fundamental purpose of the present invention is to provide a kind of output voltage detecting circuit and switched power supplier; Wherein, Output voltage detecting circuit can be according to output current stream bucking voltage and the corresponding detection signal that produces of output voltage through conduction layout (like the Copper Foil of printed circuit board (PCB) or other conducting metal or the like); Owing to utilize the adjustment of conduction layout to plan the conduction pressure drop of offset supply line, make detection signal can reflect the conduction pressure drop of power lead, and it be poor to be able to bucking voltage; Relatively make the magnitude of voltage variable quantity of the circuit system power end voltage that is sent to circuit system less, and voltage regulation factor is less.In addition, output voltage detecting circuit and switched power supplier need not cooperate extra load detecting circuit, not only make the circuit of output voltage detecting circuit and switched power supplier simpler, and manufacturing cost are relatively low and volume is less.More do not need two detection lines that are connected in the circuit system power end of extra increase,, can be applied to circumscribed or portable power supply device that some limit whole wire rod size so can not make whole wire rod become thicker.
For reaching above-mentioned purpose; Of the present invention one than broad sense embodiment for a kind of output voltage detecting circuit is provided; Comprise: the conduction layout; The conduction layout comprises power-output terminal, first end and second end at least, and output current flow through first end and second end, makes between first end and second end and produces bucking voltage; Mu balanced circuit, the earth terminal of mu balanced circuit is connected in first end, in order to adjusting first electric current according to first circuit end of mu balanced circuit and the voltage between earth terminal, and produces detection signal according to first electric current; First resistance is connected in first circuit end of second end and mu balanced circuit; And second resistance, be connected in first circuit end and the power supply positive output end of mu balanced circuit; Wherein, First resistance and second resistance produce branch pressure voltage with the output voltage dividing potential drop between power supply positive output end and power-output terminal; And first circuit end and the voltage between earth terminal of mu balanced circuit are the poor of branch pressure voltage and bucking voltage; This power supply positive output end also is connected a power lead with this power-output terminal; And transmit circuit system power end voltage to one circuit system by this power lead, this conduction layout is arranged on the path of this output current that is flowed back to by this power lead, and this output current flow through in regular turn this power-output terminal, this first end and this second end.
For reaching above-mentioned purpose; Of the present invention one than broad sense embodiment for a kind of switched power supplier is provided; Comprise: output voltage detecting circuit comprises: the conduction layout, and the conduction layout comprises power-output terminal, first end and second end at least; And output current flow through first end and second end make between first end and second end and produce bucking voltage; Mu balanced circuit, the earth terminal of mu balanced circuit is connected in first end, in order to adjusting first electric current according to first circuit end of mu balanced circuit and the voltage between earth terminal, and produces detection signal according to first electric current; First resistance is connected in first circuit end of second end and mu balanced circuit; And second resistance, be connected in first circuit end and the power supply positive output end of mu balanced circuit; Main power circuit comprises on-off circuit, and main power circuit is connected in power supply positive output end and conduction layout, produces output voltage in order to the electric energy that receives input voltage; And control circuit, be connected in the control end and the output voltage detecting circuit of the on-off circuit of main power circuit, in order to according to detection signal CS circuit turn-on with end, make the magnitude of voltage conversion of input voltage is produced output voltage; Wherein, First resistance and second resistance produce branch pressure voltage with the output voltage dividing potential drop between power supply positive output end and power-output terminal; And first circuit end and the voltage between earth terminal of mu balanced circuit are the poor of branch pressure voltage and bucking voltage; This power supply positive output end also is connected a power lead with this power-output terminal; And transmit circuit system power end voltage to one circuit system by this power lead, this conduction layout is arranged on the path of this output current that is flowed back to by this power lead, this output current flow through in regular turn this power-output terminal, this first end and this second end.
Description of drawings
Figure 1A: be the output voltage detecting circuit synoptic diagram of the preferred embodiment of the present invention.
Figure 1B: be the output voltage detecting circuit synoptic diagram of another preferred embodiment of the present invention.
Fig. 1 C: be the output voltage detecting circuit synoptic diagram of another preferred embodiment of the present invention.
Fig. 2: be the printed circuit board (PCB) synoptic diagram of the output voltage detecting circuit of the preferred embodiment of the present invention.
Fig. 3: be the circuit diagram of the switched power supplier of the preferred embodiment of the present invention.
Fig. 4: be the circuit diagram of the switched power supplier of another preferred embodiment of the present invention;
And the description of reference numerals in the above-mentioned accompanying drawing is following:
1: switched power supplier 11: output voltage detecting circuit
110: conduction layout 111: mu balanced circuit
112: barrier assembly 13: main power circuit
131: on-off circuit 14: control circuit
3: printed-wiring board (PWB) 8: power lead
9: circuit system B
1: first end
B
2: the second end R
1: first resistance
R
2: second resistance R
3: the 3rd resistance
D
1: the first diode D
2: second diode
C
1: first capacitor C
2: second electric capacity
T: transformer N
p: elementary winding
N
s: secondary winding P
1: the power supply positive output end
P
2: power-output terminal I
o: output current
I
1: the first electric current V
o: output voltage
V
R1: branch pressure voltage V
x: bucking voltage
V
f: detection signal V
d: circuit system power end voltage
COM
1: first meets end L altogether
1: first inductance
V
L: conduction pressure drop 111A: first circuit end
111B: second circuit end 111G: earth terminal
V
AG: first circuit end of mu balanced circuit and the voltage between earth terminal
Embodiment
Some exemplary embodiments that embody characteristic of the present invention and advantage will be described in detail in the explanation of back segment.Be understood that the present invention can have various variations on different aspects, its neither departing from the scope of the present invention, and explanation wherein and be shown in the usefulness of being used as explanation in essence, but not in order to restriction the present invention.
See also Figure 1A, it is the output voltage detecting circuit synoptic diagram of the preferred embodiment of the present invention.Shown in Figure 1A, output voltage detecting circuit 11 is connected in the power supply positive output end P of switched power supplier 1
1With power lead 8, output voltage detecting circuit 11 comprises: conduction layout 110, mu balanced circuit 111, first resistance R
1And second resistance R
2, wherein, conduction layout 110 has power-output terminal P
2, the first end B
1With the second end B
2, and conduction layout 110 is arranged at the output current I that is flowed back to by power lead 8
oThe path on.Because the first end B of conduction layout 110
1With the second end B
2So non-same end is output current I
oThe first end B of the conduction layout 110 of flowing through
1With the second end B
2The time, at the first end B
1With the second end B
2Between can produce bucking voltage V
xAnd the first end B
1Be arranged at output current I
oThe front side of the conduction layout 110 of flowing through, the second end B
2Be arranged at output current I
oThe rear side of the conduction layout 110 of flowing through, therefore, the output current I that flows back to by power lead 8
oPower-output terminal P in regular turn can flow through
2, the first end B
1With the second end B
2In other words, the first end B of conduction layout 110
1Than the second end B
2Near power-output terminal P
2, by the first end B of conduction layout 110
1To power-output terminal P
2Path by the second end B of conduction layout 110
2To power-output terminal P
2Path short, output current I
oCan flow through the first end B of conduction layout 110 earlier
1Flow through the second end B of conduction layout 110 again
2
In some embodiment, the first end B of conduction layout 110
1With power-output terminal P
2Be same end (not shown), likewise, can make output current I
oThe first end B of the conduction layout 110 of flowing through
1With the second end B
2The time, at the first end B
1With the second end B
2Between can produce bucking voltage V
xAnd the first end B
1Be arranged at output current I
oThe front side of the conduction layout 110 of flowing through, the second end B
2Be arranged at output current I
oThe rear side of the conduction layout 110 of flowing through, therefore, the output current I that flows back to by power lead 8
oThe first end B in regular turn can flow through
1With the second end B
2
It is voltage stabilizing IC or the stabipack realization of TL431 that mu balanced circuit 111 can be selected Texas Instruments (TI) model for use; But not as limit; In some embodiment; Mu balanced circuit 111 also can be formed (not shown) by operational amplifier (Operational Amplifier, OP Amp) and resistance, in order to according to first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G (ground)
AGWith the reference voltage in the mu balanced circuit 111, for example 2.495 volts, adjustment flows into first electric current I of the second circuit end 111B of mu balanced circuit 111 automatically
1, and according to this first electric current I
1Produce detection signal V
f, so detection signal V
fEqually can be along with first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G
AGAnd change.The earth terminal 111G of mu balanced circuit 111 is connected in the first end B of conduction layout 110
1, the first circuit end 111A of mu balanced circuit 111 is connected in first resistance R
1With second resistance R
2An end, first resistance R
1The other end be connected in the conduction layout 110 the second end B
2, second resistance R
2The other end be connected in power supply positive output end P
1
In some embodiment; When mu balanced circuit 111 uses Texas Instruments's model to realize as the voltage stabilizing IC of TL431 (not shown), the reference edge of this TL431, cathode terminal and the corresponding respectively first circuit end 111A, second circuit end 111B and the earth terminal 111G that is connected in mu balanced circuit 111 of anode tap.
See also Figure 1A and Figure 1B, wherein Figure 1B is the output voltage detecting circuit synoptic diagram of another preferred embodiment of the present invention.Figure 1B and Figure 1A difference are that the output voltage detecting circuit 11 of Figure 1B also comprises a barrier assembly 112, and the input side of barrier assembly 112 is connected in power supply positive input terminal P
1And between the second circuit end 111B of mu balanced circuit 111, and the outgoing side of barrier assembly 112 be connected in first connect altogether the end COM
1Therefore, first electric current I
1Also can the flow through input side of barrier assembly 112, and the outgoing side of barrier assembly 112 can be according to first electric current I of the input side that flows into barrier assembly 112
1Produce detection signal V
f
See also Figure 1B and Fig. 1 C, wherein Fig. 1 C is the output voltage detecting circuit synoptic diagram of another preferred embodiment of the present invention.Fig. 1 C and Figure 1B difference are that the output voltage detecting circuit 11 of Fig. 1 C also comprises one the 3rd resistance R
3, the 3rd resistance R
3Be connected in series in power supply positive input terminal P with the input side of barrier assembly 112
1And between the second circuit end 111B of mu balanced circuit 111.In present embodiment, the 3rd resistance R
3An end be connected in power supply positive input terminal P
1, the 3rd resistance R
3The other end be connected in an end of the input side of barrier assembly 112, the other end of the input side of barrier assembly 112 is connected in the second circuit end 111B of mu balanced circuit 111.So, first electric current I
1Except flowing through the input side of barrier assembly 112, the 3rd resistance R of also can flowing through
3
Output voltage detecting circuit 11 utilizes first resistance R
1With second resistance R
2With power supply positive output end P
1With power-output terminal P
2Between output voltage V
oDividing potential drop and in first resistance R
1Two ends produce branch pressure voltage V
R1, output voltage V wherein
oWith branch pressure voltage V
R1Relational expression does
And first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G
AGBe branch pressure voltage V
R1With bucking voltage V
xPoor, its relational expression does
Promptly
V
R1＝V
AG+V
X。
Therefore, receive first electric current I of mu balanced circuit 111 adjustment
1Can be along with branch pressure voltage V
R1With bucking voltage V
xAnd change, relatively, detection signal V
fAlso along with branch pressure voltage V
R1With bucking voltage V
xAnd change.Because branch pressure voltage V
R1Be along with output voltage V
oChange, and bucking voltage V
xBe along with output current I
oChange, so, detection signal V
fCan be along with output voltage V
oWith output current I
oChange.
The output current I of power lead 8 owing to flow through
oCan make power lead 8 produce conduction pressure drop V
L, make circuit system power end voltage V
dMagnitude of voltage equal output voltage V
oSubtract conduction pressure drop V
L, its relational expression is V
d=V
o-V
L, and then cause switched power supplier 1 to be sent to the circuit system power end voltage V of circuit system 9
dMagnitude of voltage less than output voltage V
oMagnitude of voltage.Therefore, if use traditional output voltage detecting circuit 11 according to output voltage V
oProduce detection signal V
fMagnitude of voltage can be greater than according to circuit system power end voltage V
dProduce detection signal V
fMagnitude of voltage.Yet, bucking voltage V of the present invention
xBe along with output current I
oChange, this characteristic is same as along with output current I
oThe conduction pressure drop V that changes
L, therefore, output voltage detecting circuit 11 of the present invention is to utilize bucking voltage V
xThe conduction pressure drop V of offset supply line 8
L, can make detection signal V
fAlso reflect the conduction pressure drop V of power lead 8
L
See also Fig. 2, it is the printed circuit board (PCB) synoptic diagram of the output voltage detecting circuit of the preferred embodiment of the present invention.As shown in Figure 2, (Printed circuit board, PCB) the conduction layout 110 in 3 has power-output terminal P to printed circuit board (PCB)
2, the first end B
1With the second end B
2, wherein, the conduction layout 110 of printed circuit board (PCB) 3 can utilize Copper Foil or other conducting metal or the like to realize, not as limit.And power lead 8 is connected to power supply positive output end P
1, power-output terminal P
2With circuit system 9.Output current I
oBy power supply positive output end P
1Flow out and flow through power lead 8 and circuit system 9, again by power-output terminal P
2Flow back to conduction layout 110.Likewise, the flow through output current I of power lead 8
oCan make power lead 8 produce conduction pressure drop V
L, and cause circuit system power end voltage V
dMagnitude of voltage less than power supply positive output end P
1With power-output terminal P
2Between output voltage V
oMagnitude of voltage.
Wherein, conduction layout 110 is arranged at the output current I that is flowed back to by power lead 8
oThe path on since the conduction layout 110 the first end B
1With the second end B
2So non-same end is output current I
oThe first end B of the conduction layout 110 of flowing through
1With the second end B
2The time, at the first end B
1With the second end B
2Between can produce bucking voltage V
x, and the first end B
1Be arranged at output current I
oThe front side of the conduction layout 110 of flowing through, the second end B
2Be arranged at output current I
oThe rear side of the conduction layout 110 of flowing through, therefore, the output current I that flows back to by power lead 8
oPower-output terminal P in regular turn can flow through
2, the first end B
1With the second end B
2, in other words, the first end B of conduction layout 110
1Near power-output terminal P
2, by the first end B of conduction layout 110
1To power-output terminal P
2Path by the second end B of conduction layout 110
2To power-output terminal P
2Path short, output current I
oCan flow through the first end B of conduction layout 110 earlier
1Flow through the second end B of conduction layout 110 again
2
Because the shape of conduction layout 110 can constitute conductive path, makes output current I
oThe first end B in regular turn flows through
1With the second end B
2, therefore, the shape of conduction layout 110 does not limit, in some embodiment, conduction layout 110 be shaped as rectangle (not shown), its purpose is at the first end B that makes conduction layout 110
1With the second end B
2Between resistance characteristic design more easily.
See also Fig. 1 C and Fig. 3, wherein Fig. 3 is the circuit diagram of the switched power supplier of the preferred embodiment of the present invention.Switched power supplier 1 as shown in Figure 3 also comprises main power circuit 13 and control circuit 14 except comprising the output voltage detecting circuit 11 shown in Fig. 1 C, and main power circuit 13 is connected in control circuit 14, power supply positive output end P
1, conduction layout 110, in order to receive input voltage V
InElectric energy and conversion input voltage V
InMagnitude of voltage and produce output voltage V
oIn present embodiment, main power circuit 13 comprises transformer T, on-off circuit 131, the first diode D
1And first capacitor C
1, wherein, transformer T has elementary winding N
pWith secondary winding N
s, and the elementary winding N of transformer T
pBe connected secondary winding N with on-off circuit 131
sAn end be connected in the first diode D
1Anode tap, secondary winding N
sThe other end be connected in the conduction layout 110.On-off circuit 131 is connected in elementary winding N
p, first connect altogether the end COM
1And control circuit 14, and, make input voltage V by the operation of control circuit 14 CS circuit 12
InElectric energy by the elementary winding N of transformer T
pBe sent to secondary winding N
sThe first diode D
1Anode tap be connected in secondary winding N
sAn end, the first diode D
1Cathode terminal be connected in first capacitor C
1An end and power supply positive output end P
1, and first capacitor C
1The other end be connected in the conduction layout 110.
Likewise, output voltage detecting circuit 11 utilizes first resistance R
1With second resistance R
2With power supply positive output end P
1With power-output terminal P
2Between output voltage V
oDividing potential drop and in first resistance R
1Two ends produce branch pressure voltage V
R1, output voltage V wherein
oWith branch pressure voltage V
R1Relational expression does
And first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G
AGBe branch pressure voltage V
R1With bucking voltage V
xPoor, its relational expression does
Promptly
V
R1＝V
AG+V
X。
Therefore, receive first electric current I of mu balanced circuit 111 adjustment
1Can be along with branch pressure voltage V
R1With bucking voltage V
xAnd change, relatively, detection signal V
fAlso along with branch pressure voltage V
R1With bucking voltage V
xAnd change.Because branch pressure voltage V
R1Be along with output voltage V
oChange, and bucking voltage V
xBe along with output current I
oChange, so, detection signal V
fCan be along with output voltage V
oWith output current I
oChange.
Bucking voltage V of the present invention
xBe along with output current I
oChange, this characteristic is same as along with output current I
oThe conduction pressure drop V that changes
L, therefore, output voltage detecting circuit 11 of the present invention is to utilize bucking voltage V
xThe conduction pressure drop V of offset supply line 8
L, can be so that detection signal V
fReflect the conduction pressure drop V of power lead 8
L, relatively make output voltage V
oBe compensated, and switched power supplier 1 is sent to the circuit system power end voltage V of circuit system 9 by power lead 8
dMagnitude of voltage also can be compensated, make circuit system power end voltage V
dThe magnitude of voltage variable quantity less.
For example, output voltage V
oLoad voltage value be 12 volts, but traditional exchange formula power supply unit is sent to the circuit system power end voltage V of circuit system 9 via power lead 8
dMagnitude of voltage but be not 12 volts load voltage value, in switched power supplier 1 of the present invention by bucking voltage V
xThe conduction pressure drop V of offset supply line 8
L, can make the circuit system power end voltage V that is sent to circuit system 9
dMaintain 12 volts load voltage value.
See also Figure 1A, Fig. 3 and Fig. 4, wherein Fig. 4 is the circuit diagram of the switched power supplier of another preferred embodiment of the present invention.The switched power supplier 1 of Fig. 4 and Fig. 3 is except main power circuit 13 is different; Fig. 4 is also different with the employed output voltage detecting circuit 11 of the switched power supplier of Fig. 3, and the output voltage detecting circuit 11 of the switched power supplier 1 of Fig. 4 is the output voltage detecting circuit 11 shown in Figure 1A.
In Fig. 4, main power circuit 13 packet switch circuit 131, first inductance L
1, the second diode D
2And second capacitor C
2, wherein, on-off circuit 131 is connected in control circuit 14, first inductance L
1An end, the second diode D
2Cathode terminal.First inductance L
1An end be connected in the on-off circuit 131 and the second diode D
2Cathode terminal, first inductance L
1The other end be connected in second capacitor C
2An end.The second diode D
2Anode tap be connected in conduction layout 110, the second diode D
2Cathode terminal be connected in the on-off circuit 131 and first inductance L
1An end.Second capacitor C
2An end be connected in first inductance L
1The other end, second capacitor C
2The other end be connected in the conduction layout 110.
Similarly, output voltage detecting circuit 11 utilizes first resistance R
1With second resistance R
2With power supply positive output end P
1With power-output terminal P
2Between output voltage V
oDividing potential drop and in first resistance R
1Two ends produce branch pressure voltage V
R1, output voltage V wherein
oWith branch pressure voltage V
R1Relational expression does
And first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G
AGBe branch pressure voltage V
R1With bucking voltage V
xPoor, its relational expression does
Promptly
V
R1＝V
AG+V
X。
Therefore, receive first electric current I of mu balanced circuit 111 adjustment
1Can be along with branch pressure voltage V
R1With bucking voltage V
xAnd change, relatively, detection signal V
fAlso along with branch pressure voltage V
R1With bucking voltage V
xAnd change.Because branch pressure voltage V
R1Be along with output voltage V
oChange, and bucking voltage V
xBe along with output current I
oChange, so, detection signal V
fCan be along with output voltage V
oWith output current I
oChange.In some embodiment, at control circuit 14 according to detection signal V
fDuring 131 operations of adjustment on-off circuit, can make first circuit end 111A of mu balanced circuit 111 and the voltage V between earth terminal 111G
AGEqual the reference voltage in the mu balanced circuit 111, for example 2.495 volts.
Bucking voltage V of the present invention
xBe along with output current I
oChange, this characteristic is same as along with output current I
oThe conduction pressure drop V that changes
L, therefore, output voltage detecting circuit 11 of the present invention is to utilize bucking voltage V
XThe conduction pressure drop V of offset supply line 8
L, can be so that detection signal V
fReflect the conduction pressure drop V of power lead 8
L, relatively make output voltage V
oBe compensated, and switched power supplier 1 is sent to the circuit system power end voltage V of circuit system 9 by power lead 8
dMagnitude of voltage also can be compensated, make circuit system power end voltage V
dThe magnitude of voltage variable quantity less.
In sum, output voltage detecting circuit of the present invention can be according to the conduction layout generating bucking voltage and the corresponding detection signal that produces of output voltage of output current stream process, owing to utilize the conduction pressure drop V of the bucking voltage offset supply line of conduction layout
L, make detection signal can reflect the conduction pressure drop V of power lead
L, relatively make the magnitude of voltage variable quantity of the circuit system power end voltage that is sent to circuit system less, and voltage regulation factor is less.In addition, output voltage detecting circuit need not cooperate extra load detecting circuit, not only make the circuit of output voltage detecting circuit simpler, and manufacturing cost is relatively low and volume is less.More do not need two detection lines that are connected in the circuit system power end of extra increase,, can be applied to circumscribed or portable power supply device that some limit whole wire rod size so can not make whole wire rod become thicker.
In addition; The output voltage detecting circuit of switched power supplier of the present invention can flow the bucking voltage and the corresponding detection signal that produces of output voltage of the conduction layout of process according to output current, owing to utilize the conduction pressure drop V of the bucking voltage offset supply line of conduction layout
L, make detection signal can reflect the conduction pressure drop V of power lead
LOutput voltage is compensated; And switched power supplier also can be compensated by the magnitude of voltage that power lead is sent to the circuit system power end voltage of circuit system, make the magnitude of voltage variable quantity of circuit system power end voltage less, and voltage regulation factor is less.In addition, output voltage detecting circuit need not cooperate extra load detecting circuit, not only make the circuit of switched power supplier simpler, and manufacturing cost is relatively low and volume is less.More do not need two detection lines that are connected in the circuit system power end of extra increase, so can not make whole wire rod become thicker.
The present invention must be thought and is to modify the right neither claimed scope of accompanying claims of taking off as all by ordinary skill Shi Renshi craftsman.
Claims (16)
1. output voltage detecting circuit comprises:
One conduction layout, this conduction layout comprises a power-output terminal, one first end and one second end at least, and an output current flow through this first end and this second end, makes generation one bucking voltage between this first end and this second end;
One mu balanced circuit, the earth terminal of this mu balanced circuit are connected in this first end, adjust one first electric current in order to first circuit end and the voltage between earth terminal according to this mu balanced circuit, and produce a detection signal according to this first electric current;
One first resistance is connected between first circuit end of this second end and this mu balanced circuit; And
One second resistance is connected between first circuit end and a power supply positive output end of this mu balanced circuit;
Wherein, This first resistance and this second resistance produce a branch pressure voltage with the output voltage dividing potential drop between this power supply positive output end and this power-output terminal; And first circuit end of this mu balanced circuit and the voltage between earth terminal are the poor of this branch pressure voltage and this bucking voltage; This power supply positive output end also is connected a power lead with this power-output terminal; And transmit circuit system power end voltage to one circuit system by this power lead, this conduction layout is arranged on the path of this output current that is flowed back to by this power lead, and this output current flow through in regular turn this power-output terminal, this first end and this second end.
2. output voltage detecting circuit as claimed in claim 1; Also comprise a barrier assembly; The input side of this barrier assembly is connected between the second circuit end of this power supply positive input terminal and this mu balanced circuit, and produces this detection signal according to this first electric current in the outgoing side of this barrier assembly.
3. output voltage detecting circuit as claimed in claim 2 also comprises one the 3rd resistance, and the input side of this barrier assembly and the 3rd resistance are connected in series between the second circuit end of this power supply positive input terminal and this mu balanced circuit.
4. output voltage detecting circuit as claimed in claim 1, wherein this first end and this power-output terminal are same end.
5. output voltage detecting circuit as claimed in claim 1, wherein this branch pressure voltage is the voltage at these first resistance two ends.
6. output voltage detecting circuit as claimed in claim 1, wherein this first end is shorter than the path of this second end to this power-output terminal to the path of this power-output terminal.
7. output voltage detecting circuit as claimed in claim 1, wherein this first end is arranged at the front side of this conduction layout, and this second end is arranged at the rear side of this conduction layout.
8. switched power supplier comprises:
One output voltage detecting circuit comprises: a conduction layout, a mu balanced circuit, one first resistance and one second resistance;
This conduction layout comprises a power-output terminal, one first end and one second end at least, and an output current flow through this first end and this second end, makes and produces a bucking voltage between this first end and this second end;
The earth terminal of this mu balanced circuit is connected in this first end, adjusts one first electric current in order to first circuit end and the voltage between earth terminal according to this mu balanced circuit, and produces a detection signal according to this first electric current;
This first resistance is connected between first circuit end of this second end and this mu balanced circuit;
This second resistance is connected between first circuit end and a power supply positive output end of this mu balanced circuit;
One main power circuit comprises an on-off circuit, and this main power circuit is connected between this power supply positive output end and this conduction layout, produces an output voltage in order to the electric energy that receives an input voltage; And
One control circuit; Be connected between the control end and this output voltage detecting circuit of this on-off circuit of this main power circuit; In order to according to this on-off circuit conducting of this detection signal control with end, make the magnitude of voltage conversion of this input voltage is produced this output voltage;
Wherein, This first resistance and this second resistance produce a branch pressure voltage with this output voltage dividing potential drop between this power supply positive output end and this power-output terminal; And first circuit end of this mu balanced circuit and the voltage between earth terminal are the poor of this branch pressure voltage and this bucking voltage; This power supply positive output end also is connected a power lead with this power-output terminal; And transmit circuit system power end voltage to one circuit system by this power lead, this conduction layout is arranged on the path of this output current that is flowed back to by this power lead, this output current flow through in regular turn this power-output terminal, this first end and this second end.
9. switched power supplier as claimed in claim 8; Wherein this output voltage detecting circuit also comprises a barrier assembly; The input side of this barrier assembly is connected between the second circuit end of this power supply positive input terminal and this mu balanced circuit, and produces this detection signal according to this first electric current in the outgoing side of this barrier assembly.
10. switched power supplier as claimed in claim 8, wherein this main power circuit also comprises:
One transformer has an elementary winding and a level winding, and this elementary winding is connected in this on-off circuit, and this secondary winding is connected in this conduction layout;
One first diode, the anode tap of this first diode are connected in an end of this secondary winding, and the cathode terminal of this first diode is connected in this power supply positive output end; And
One first electric capacity, an end of this first electric capacity is connected in the second circuit end of this first diode, and the other end of this first electric capacity is connected in this conduction layout.
11. switched power supplier as claimed in claim 8, wherein this main power circuit also comprises:
One first inductance, an end of this first inductance is connected in this on-off circuit;
One second diode, the anode tap of this second diode are connected in this conduction layout, and the cathode terminal of this second diode is connected in an end of this on-off circuit and this first inductance; And
One second electric capacity, an end of this second electric capacity is connected in the other end of this first inductance, and the other end of this second electric capacity is connected in this conduction layout.
12. switched power supplier as claimed in claim 8, wherein this control circuit is Pwm controller or pulse frequency modulation controller.
13. switched power supplier as claimed in claim 8, wherein this branch pressure voltage is the voltage at these first resistance two ends.
14. switched power supplier as claimed in claim 8, wherein this first end is shorter than the path of this second end to this power-output terminal to the path of this power-output terminal.
15. switched power supplier as claimed in claim 8, wherein this first end is arranged at the front side of this conduction layout, and this second end is arranged at the rear side of this conduction layout.
16. switched power supplier as claimed in claim 8, wherein this first end and this power-output terminal are same end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810184922A CN101762734B (en) | 2008-12-23 | 2008-12-23 | Output voltage detection circuit and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810184922A CN101762734B (en) | 2008-12-23 | 2008-12-23 | Output voltage detection circuit and switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN101762734A CN101762734A (en) | 2010-06-30 |
| CN101762734B true CN101762734B (en) | 2012-09-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200810184922A Active CN101762734B (en) | 2008-12-23 | 2008-12-23 | Output voltage detection circuit and switching power supply |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106291065B (en) * | 2016-10-17 | 2023-05-16 | 成都前锋电子仪器有限责任公司 | Voltage sampling circuit |
| CN107576839A (en) * | 2017-09-18 | 2018-01-12 | 唐山松下产业机器有限公司 | Welding equipment, weldingvoltage detection method and device |
| TWI699083B (en) * | 2019-04-16 | 2020-07-11 | 宏碁股份有限公司 | Power supply circuit with line compensation |
| CN110971134B (en) * | 2019-12-19 | 2021-06-22 | 南京微盟电子有限公司 | Rectifier diode voltage drop compensation system of non-isolated switch power supply |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5589759A (en) * | 1992-07-30 | 1996-12-31 | Sgs-Thomson Microelectronics S.R.L. | Circuit for detecting voltage variations in relation to a set value, for devices comprising error amplifiers |
-
2008
- 2008-12-23 CN CN200810184922A patent/CN101762734B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5589759A (en) * | 1992-07-30 | 1996-12-31 | Sgs-Thomson Microelectronics S.R.L. | Circuit for detecting voltage variations in relation to a set value, for devices comprising error amplifiers |
Non-Patent Citations (2)
| Title |
|---|
| JP特开2004-212275A 2004.07.29 |
| JP特开平10-42467A 1998.02.13 |
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| CN101762734A (en) | 2010-06-30 |
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