CN106899217B - The switch type power supplying device of fast load transient reaction - Google Patents
The switch type power supplying device of fast load transient reaction Download PDFInfo
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- CN106899217B CN106899217B CN201510960027.XA CN201510960027A CN106899217B CN 106899217 B CN106899217 B CN 106899217B CN 201510960027 A CN201510960027 A CN 201510960027A CN 106899217 B CN106899217 B CN 106899217B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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- Dc-Dc Converters (AREA)
Abstract
Embodiment provides the switch type power supplying device of a Fast Load transient state transient response, has the primary side and a primary side of isolation.The power supply unit includes a primary side control circuit and a secondary-side control circuitry.The primary side control circuit is set to the primary side, and controls a power switch, will be located at an input power of the primary side, and be converted to the out-put supply positioned at the primary side.The out-put supply has an output voltage.The secondary-side control circuitry is set to the primary side and can detect a fall off rate of the output voltage to detect the output voltage.When the fall off rate is greater than a predetermined value, which can provide information to the primary side control circuit.When the primary side control circuit receives the information, which starts a switch periods, will pass through an inductance element, detects and calibrates the output voltage.
Description
Technical field
The present invention relates to a kind of switch type power supplying devices, espespecially using the switch type power supplying device of primary side control.
Background technique
Power supply unit is almost device essential to all electronic products.For example, power supply unit can will be handed over
Stream alternating current is converted to power specification required for the main circuit (core circuit) of electronic product.It is supplied in all power supplys
In device, switch type power supplying device has the advantages that transfer efficiency is good and small product size is small, therefore by the universal of industry
Using.
Generally have to prevent user by unnecessary lightning stroke or the high voltage damage of alternating current, power supply unit
The primary side and primary side being isolated, between the two without DC current.Voltage level positioned at primary side is all referring to alternating current
Input ground；And the voltage level for being located at primary side is then the output ground with reference to a floating.
Switch type power supplying device can generate pulse width in primary side and modulate (PWM) signal, to control a power switch,
Use the electric energy that control is transformed into primary side from primary side, it is therefore an objective to keep the out-put supply in primary side up to specification.
For example, the output voltage of out-put supply can be made about to maintain in an allowable range very close to 5V.
In general, primary side control is to pass through induction electric caused by an inductance element as being located at the circuit of primary side
Gesture is detected the output voltage positioned at primary side indirectly.Comparatively, primary side control is by being located at the circuit of primary side Lai straight
Detection output voltage is connect, then by photo-coupler, establishes offset voltage in primary side.
In order to reduce the switching losses (switching loss) of power switch, in no-load or pwm signal at light load
Switching frequency can design very low mostly.In other words, no-load or at light load, the power switch meeting of switch type power supplying device
The a period of time of open-circuit condition for a long time is maintained, short-circuit condition is then just switched to.At this point, if switch type power supplying device exists
The load that primary side is powered is converted into heavy duty from no-load or underloading suddenly, how to allow the pwm signal of primary side quickly anti-
It should be exactly critically important project.Such reaction speed is known as load transient reaction (load-transient response).Especially
It is the power supply unit of primary side control, and in no-load or at light load, almost most times are in blindly secondary without knowing
In the state of the output voltage of grade side.If load transient reaction is not fast enough, output voltage may be made, which to drop to, to be held
Perhaps except range.
Summary of the invention
One embodiment of the invention provides a power supply unit, has the primary side and a primary side of isolation.It should
Power supply unit includes a primary side control circuit and a secondary-side control circuitry.The primary side control circuit is set to the primary
Side, and a power switch is controlled, an input power of the primary side will be located at, be converted to the output electricity positioned at the primary side
Source.The out-put supply has an output voltage.The secondary-side control circuitry is set to the primary side can to detect the output voltage
Detect a fall off rate of the output voltage.When the fall off rate is greater than a predetermined value, which can be mentioned
For information to the primary side control circuit.When the primary side control circuit receives the information, which starts
One switch periods detect will pass through an inductance element and calibrate the output voltage.
Detailed description of the invention
Fig. 1 is a charger caused by embodiment according to the present invention.
Fig. 2A is displayed without a kind of possible outcome when fast reaction of the invention.
Fig. 2 B shows a kind of possible outcome of the charger 60 of Fig. 1 under fast reaction.
Fig. 3 A shows the control method of embodiment according to the present invention.
Fig. 3 B shows Key dithering time TDEBOUNCEDefinition.
Fig. 4 illustrates how to differentiate fall off rate RADROPWhether a preset value RA is greater thanREFA kind of circuit box schematic diagram.
Fig. 5 to Fig. 8 shows four fall off rate detectors.
[accompanying drawings symbol description]
12 USB connectors
14P primary side
14S primary side
16 bridge rectifiers
26 photo-couplers
26E transmitter
26R receiver
60 chargers
62 secondary side controllers
64 primary side controllers
66,68,70 resistance
80 control methods
82,84,86,88 step
90 Voltage-current conversion circuits
92 track and hold circuits
94 adders
96 resolvers
100 fall off rate detectors
102L, 102R Voltage-current conversion circuit
104 comparison circuits
106 resolvers
108 adders
110 fall off rate detectors
112 Voltage-current conversion circuits
114 current mirrors
116 analog-digital converters
118 counters
120 current generators
122 digital latch
124 current generators
125 current sources
126 resolvers
130 fall off rate detectors
The current mirror of 132 deformations
140 fall off rate detectors
142 current memories
144 current mirrors
CGCapacitor
CKT/HSampling clock
CKBT/HAnti- sampling clock
FB feedback end
fREFPredeterminated frequency
fSWPwm signal SPWMFrequency
GNDI input ground
GNDO output ground
I3Electric current
I1、I2Represent electric current
I(t)、I(tSAMP) represent electric current
ILFRepresent electric current
IREFPreset reference electric current
IRESULTAs a result electric current
LA auxiliary winding
LP main winding
LS secondary windings
MERG merges end
MN1, MN2 NMOS transistor
MP1 PMOS transistor
The receiving end OPTO
RADROPFall off rate
RAREFPreset value
The test side SEN
SPWMPwm signal
SWAKEUPWake-up signal
SW power switch
SWLFSwitch
SWRECTRectifier switch
SWRTSwitch
SWSAMPSwitch
tCHK、tHEAVY-LOAD、tNO-LOAD、tRESP、tSAMPTime point
TOFFShut-in time
TONOpening time
TSWSwitch periods
TDEBOUNCEThe Key dithering time
TDISDischarge time
TIDLETime of having a rest
VAC-INElectric main
VBUS out-put supply
VBUSOutput voltage
VIN input power
VLIMIT-BTMThe minimum voltage allowed
VREFReference voltage
VREF1Preset voltage value
VTRGTDesired value
Specific embodiment
In the present specification, have some identical symbols, expression have the function of identical or similar structure, principle
Element, and for those skilled in the art can according to this specification introduction and deduce.It is considered for the succinct degree of specification, phase
The element of same symbol will be repeated no longer.
Fig. 1 is a charger 60 caused by embodiment according to the present invention, is a switch type power supplying device, can be with
It charges to the electronic device (not shown) being connected on USB connector 12.It is considered in order to for security, charger 60 has
It is galvanically isolated the primary side 14P and primary side 14S of (galvanic insolated).Do not have between primary side 14P and primary side 14S
There is the connection of DC.Circuit (including primary side controller 64) positioned at primary side 14P is mainly with input power VIN and input ground
GNDI powers, and input power VIN and input ground GNDI are then according to electric main VAC-INBy bridge rectifier 16, pass through
Full-wave rectification and generate.By the electric discharge of secondary windings LS, primary side 14S can produce out-put supply VBUS and output ground
GNDO supplies electricity to the circuit positioned at primary side 14S, and it includes secondary side controllers 62 and the electricity being connected on USB connector 12
Sub-device.
Main winding LP and auxiliary winding LA are located at primary side 14P, and secondary windings LS is located at primary side 14S.By switch function
Rate switch SW, primary side controller 64 control the electric current for flowing through main winding LP.In this way, transformer (includes main winding LP, secondary
Winding LS and auxiliary winding LA) can be from input power VIN energy storage, and releasing from primary side 14S can be to establish out-put supply VBUS.
Primary side controller 64 can detect the cross-pressure of auxiliary winding LA from feedback end FB by resistance 66 and 68, utilize
The principle of induced electromotive force indirectly detects the output voltage V of out-put supply VBUSBUS.According to detected by from feedback end FB
As a result, 64 modulation (PWM) signal S of primary side controllerPWMFrequency fSWOr the duty cycle (duty cycle), control becomes whereby
The energy of depressor is converted, to calibrate output voltage VBUS.Such control technology, referred to as primary side control (primary side
control).For example, if during transformer discharge, the voltage on feedback end FB indicates output voltage VBUS
Higher, that primary side controller 64 just reduces pwm signal SPWMFrequency fSWWith the duty cycle, reduce from input power VIN with it is defeated
Enter the electric energy that ground GNDI is drawn.
Secondary side controller 62 can be a synchronous rectifying controller (synchronous rectification
Controller), rectifier switch SW is controlledRECT.Secondary side controller 62 can also be come by resistance 70 and test side SEN
The switch state for detecting power switch SW, can also learn pwm signal SPWMFrequency fSW。
Secondary side controller 62 can pass through a photo-coupler 26 (having transmitter 26E and receiver 26R), transmitting letter
It ceases to primary side 14P.This information may be it is digital, can be single one byte, or the letter with several bytes
Cease code.This information is also possible to analog, for example, adjusts to 62 analog of secondary side controller the work week of transmitter 26E
Phase, to generate a corresponding voltage level on the OPTO of receiving end.According to the voltage change on the OPTO of receiving end, primary side control
Device 64 processed can receive secondary side controller 62 and be transmitted through the information come, and carry out corresponding reaction.In this embodiment, light
Coupler 26 is used as signal path, connection primary side 14P and the both sides primary side 14S, but the present invention is not limited thereto.At other
It, can be with the element with DC current isolation features, as signal path in embodiment.For example, a transformer or
It is a capacitor, all can serve as the signal path between primary side 14P and the both sides primary side 14S.
In one embodiment of this invention, with output voltage VBUSFall off rate RADROPWhen more than a predetermined value, carry out generation
The appearance of table heavy duty.In Fig. 1, when no-load or at light load, secondary side controller 62 can detecte output voltage VBUSDecline
Rate RADROP.For example, once declining RADROPWhen greater than a predetermined value (for example 0.2V/ms), representative hangs over USB connector
Load (not shown) on 12 should become heavy duty.Therefore, secondary-side control circuitry 62 can quickly move through photo-coupler
26 notice primary side control circuits 64.For example, secondary-side control circuitry 62 makes transmitter 26E shine, and leads to primary side control
The voltage of the receiving end OPTO of circuit 64 processed declines.Once primary side control circuit 64 finds the voltage decline of receiving end OPTO
When, primary side control circuit 64 can urgent one switch periods of beginning accordingly, the unlatching for keeping power switch SW of short duration.In this way,
Primary side control circuit 64 can begin through feedback end FB and transformer, start to detect output voltage VBUSAnd it modulates accordingly
Frequency fSWOr the duty cycle, carry out steadily output voltage VBUSIn a desired value VTRGT。
Fig. 2A is displayed without a kind of possible outcome when fast reaction of the invention, and Fig. 2 B shows Fig. 1 as use is compared
A kind of possible outcome of the charger 60 under fast reaction.In Fig. 2A and Fig. 2 B, no-load is from time point tNO-LOADStart, because
This pwm signal SPWMFrequency fSWAll become very low with the duty cycle (duty cycle), makes output voltage VBUSStablize
Desired value VTRGT.Time point tHEAVY-LOADJust in pwm signal SPWMA pulse after shortly after, at that time load be changed into suddenly
Heavy duty, output voltage VBUSStart rapid decrease.
In fig. 2, the circuit of the information come without primary side 14S, primary side 14P can only be with PWM letter when script no-load
Number SPWMFrequency fSW, wait switch periods TSW(=1/fSW) after time point tCHKIt is just spontaneous to get next pulse,
As shown in the figure.At this point, the circuit of primary side 14P could find output voltage VBUSThe desired value V of script is had deviated fromTRGT,
Therefore urgent increase pwm signal SPWMFrequency fSWWith the duty cycle, it is desirable to quickly draw high output voltage VBUS, as shown in the figure.
Unfortunately, in time point tCHK, output voltage VBUSPossibility declines too low, more than the minimum voltage V allowedLIMIT-BTM。
Please refer to Fig. 1 and Fig. 2 B.Secondary side controller 62 can detect output voltage V in no-loadOUTLower reduction of speed
Rate RADROP, definition is output voltage V in the unit timeOUTReduction amount, that is, in Fig. 2 B, output voltage VOUTWaveform
Slope.In time point tRESP, the discovery of secondary side controller 62 fall off rate RADROPMore than a preset value, therefore notify primary
Side control circuit 64 rapidly makes pwm signal SPWMA pulse is got, a new switch periods are started.In putting for new switch periods
Electric time TDISInterior, primary side control circuit 64 is it can be found that output voltage VBUSDesired value V is had deviated fromTRGT, therefore it is urgent
Increase pwm signal SPWMFrequency fSWWith the duty cycle, as shown in the figure.Compare Fig. 2 B and Fig. 2A it can be found that Fig. 2 B output
Voltage VOUTIt is more stable, it may can maintain output voltage VBUSHigher than the minimum voltage V allowedLIMIT-BTMOn, can also compare
It is relatively early to return to desired value VTRGT。
Fig. 3 A shows the control method 80 of embodiment according to the present invention, the secondary side controller 62 being applicable in Fig. 1.
Problem there are three in step 82,1) pwm signal SPWMFrequency fSWWhether a predeterminated frequency f is lower thanREF(for example 1kHz)；2) it exports
Voltage VBUSWhether a preset voltage value V is lower thanREF1(for example 5.0V)；And 3) the Key dithering time (debounce time)
TDEBOUNCEWhether pass by.When these three problems answer any one whether timing, just continuously carry out step 82.Only
When the answer of three problems in step 82 is all certainly, step 84 is connected, and starts to detect output voltage VBUSFall off rate
RADROP.Step 86 subsequent steps 84 check fall off rate RADROPWhether a preset value RA is greater thanREF.If answering in step 86
Case is negative, that control method 80 returns to step 84, continues to test fall off rate RADROP., whereas if answering in step 86
Case is affirmative, and secondary side controller 62 drives transmitter 26E to shine, to carry the information to primary side control circuit 64.It is primary
Side control circuit 64 can promptly start a new switch periods accordingly.
As for three problems in step 82, when the answer of first problem is certainly, representative is frequency fSWIt is too slow, institute
To cause primary side control circuit 64 that may have little time the transient response of load, and described in Fig. 2A the problem of, may be sent out
It is raw.When the answer of Second Problem is certainly, output voltage V is representedBUSIt is relatively low that designed appearance is dropped out to the rapid decrease that has an opportunity
Perhaps outside range.As for third problem, Key dithering time T thereinDEBOUNCEDefinition be shown in Fig. 3 B.In figure 3b, PWM
Signal SPWMPulse width duration, for power switch SW maintain on state under opening time TON, transformer is from input
Power supply VIN stores energy；Opposite, pwm signal SPWMEnd-of-pulsing after, to next pulse occur before time, for close
Time TOFF, it can be subdivided into two parts again, first is that the winding current I of secondary windings LSSECDischarge time T greater than 0ADIS, separately
One be secondary windings LS winding current ISECTime of having a rest T when about 0AIDLE.In discharge time TDISIt is interior, transformer
It releases energy.As shown in Figure 3B, Key dithering time TDEBOUNCERefer to time of having a rest TIDLE-One section after beginning it is scheduled when
Between.In Key dithering time TDEBOUNCET in time of having a rest after pastIDLEJust check fall off rate RADROP, can to avoid secondary around
In group LS discharge process, for output voltage VBUSThere may be disturbances, influence fall off rate RADROPRepresentativeness.
Fig. 4 is shown in the embodiment of the present invention, how to differentiate fall off rate RADROPWhether a preset value RA is greater thanREFOne kind
Circuit box schematic diagram.Voltage-current conversion circuit 90 is by output voltage VBUSIt is converted to one and corresponding represents electric current I (t), value
About K1*(VBUS–VREF), it can be with output voltage VBUSChange and changes.K1It is a constant, reference voltage VREFIt is one
Definite value.Track and hold circuit (track-and-hold circuit) 92 is by sampling clock CKT/HIt is controlled, it can be in the time
Point tSAMPWhen, sampling represents electric current I (t), and generates and another represent electric current I (tSAMP).Represent electric current I (tSAMP) in sampling clock
CKT/HDefined retention time THOLDIt inside remains and remains unchanged, value has been corresponded approximately in time point tSAMPOutput electricity
Press VBUS(it is hereinafter denoted as VBUS(tSAMP)).Retention time THOLDTo represent electric current I (tSAMP) a period of time when remaining unchanged.
In one example, electric current I (t is representedSAMP) it is about K2*(VBUS(tSAMP)-VREF), wherein K2It is also constant.In embodiment
In, K2About design and K1It is equal, it is all indicated below with K.Adder 94 will represent electric current I (tSAMP) subtract and represent electric current I
(t) with a preset reference electric current IREF(2uA is exemplified as in figure), and generate result electric current IRESULT.In sampling clock CKT/HInstitute
The retention time T of definitionHOLDIt is interior, if result electric current IRESULTLess than 0, resolver (decider) 96 just continues forbidden energy
(deassert) wake-up signal SWAKEUP.If result electric current IRESULTGreater than 0, resolver 96 is with regard to enable (assert) wake-up signal
SWAKEUP.For example, the wake-up signal S being enabledWAKEUPIt can make secondary side controller 62 that transmitter 26E be driven to shine, with
Carry the information to primary side control circuit 64.
Described in foundation leading portion, wake-up signal SWAKEUPShown in the condition being enabled such as following formula (1)
I(tSAMP)-I(t)-IREF>0 ....(1)
After arranging formula (1), available formula (2) below
K*[VBUS(tSAMP)-VREF]–K*[VBUS-VREF]-IREF>0
VBUS(tSAMP)–VBUS>IREF/K …(2)
Formula (2) has meaned output voltage VBUSIn retention time THOLD-It is interior, as long as decreaseing beyond IREFThis constant of/K, is called out
Wake up signal SWAKEUPIt will be enabled.Output voltage VOUTIn retention time THOLDAt the end of fall off rate RADROPIt can be expressed as
[VBUS(tSAMP)–VBUS]/THOLD.It can be derived from following formula (3) from formula (2)
RADROP=[VBUS(tSAMP)–VBUS]/THOLD>IREF/(K*THOLD)=RAREF…(3)
From formula (3) it is found that the circuit box of Fig. 4, can differentiate fall off rate RADROPWhether preset value RA is greater thanREF。
Moreover, in the circuit box of Fig. 4, reference voltage VREFSelection, for differentiation as a result, not influencing.
Fig. 5 one fall off rate detector 100 of citing, for differentiating fall off rate RADROPWhether preset value RA is greater thanREF.Under
Drop rate detector 100 can be used for secondary side controller 62.Fig. 5 includes that there are two roughly the same Voltage-current conversion circuit 102L
With 102R, but the switch SW in Voltage-current conversion circuit 102LLFIt is controlled by sampling clock CKT/H, in Voltage-current conversion circuit 102R
Switch SWRTIt is controlled by anti-sampling clock CKBT/H, it is about sampling clock CKT/HIt is reversed.With Voltage-current conversion circuit
For 102L, as switch SWLFWhen to be connected, Voltage-current conversion circuit 102L tracks output voltage VBUS, generate and represent electric current ILF,
It is about (VBUS-VREF)/100k.As switch SWLFWhen to open a way, Voltage-current conversion circuit 102L is as a holding circuit, electricity
Hold CLFThe voltage record kept, can to represent electric current ILFValue be maintained at about (VBUS(tSAMP)-VREF)/100k, here
Time point tSAMPIt is approximately switch SWLFBecome the moment of open circuit from short circuit.In comparison circuit 104, depending on sampling clock CKT/HPatrol
Value is collected, two multiplexers will represent electric current ILFWith IRTOne of them replicates and becomes and represent electric current I (t), represents electric current ILFWith IRT
It is therein another, it replicates and becomes and represent electric current I (tSAMP).In other words, Voltage-current conversion circuit 102L and 102R alternately with
Track output voltage VBUS, and be converted into and represent electric current I (t).Voltage-current conversion circuit 102L and 102R are also alternately as one
Holding circuit keeps offer to represent electric current I (tSAMP), it is equal to (VBUS(tSAMP)-VREF)/100k.Adder 108 is similar to Fig. 4
In adder 94, resolver (decider) 106 is similar to the resolver (decider) 96 in Fig. 4.Work as Voltage-current conversion circuit
When 102L decision represents electric current I (t), Voltage-current conversion circuit 102R decision represents electric current I (tSAMP), retention time THOLDIt is exactly
Sampling clock CKBT/HMaintain the time span of forbidden energy (deasserted).By being previously directed to the analysis of Fig. 4 it is found that Fig. 5 institute
The fall off rate detector 100 of citing, can differentiate fall off rate RADROPWhether preset value RA is greater thanREF。
Fig. 6 shows another fall off rate detector 110, can be used for secondary side controller 62, can differentiate fall off rate
RADROPWhether preset value RA is greater thanREF.Voltage-current conversion circuit 112 is by output voltage VBUSIt is converted into corresponding electric current, is fed
Current mirror (current mirror) 114.It is assumed that the current ratio in current mirror 114 is from left to right 1:1:1.From circuit point
Analysis is it is found that represent electric current I caused by NMOS transistor MN1 and MN2 in current mirror 1141With represent electric current I2, all big appointment etc.
In I (t), that is, (VBUS-VREF)/100k.The tracking of analog-digital converter 116 represents electric current I2.According to electric current I3With represent electricity
Flow I2Comparison result, counter 118 can count above or lower number, so that electric current I caused by current generator 1203About
Equal to representing electric current I2.In other words, analog-digital converter 116 will represent electric current I2Be converted to the count results of counter 118
(a kind of digital signal).Digital latch 122 is in sampling clock CKT/HWhen switching, the counting knot of counter 118 instantly is recorded
Fruit, and current generator 124 is controlled accordingly, so that its offer is represented electric current I (tSAMP).Here time point tSAMPFor sampling clock
CKT/HThe time point of switching.When the voltage for merging end MERG is pulled to an opposite high level, 126 enable wake-up signal of resolver
SWAKEUP.Conversely, when the voltage of endpoint MERG be pulled to one it is relatively low-level when, 126 forbidden energy wake-up signal S of resolverWAKEUP.Quilt
The wake-up signal S of enableWAKEUPIt can make secondary side controller 62 that transmitter 26E be driven to shine, to carry the information to primary side control
Circuit 64 processed.And wake-up signal SWAKEUPWhen being disabled, transmitter 26E can not shine, so not carrying the information to primary side
Control circuit 64.Refering to Fig. 4 to relevant introduction it is found that the fall off rate detector 110 in Fig. 6 can differentiate fall off rate
RADROPWhether preset value RA is greater thanREF。
Current generator 124, resolver 126 can be considered as an electric current identifier with current source 125, by counter 118
Count results, which are converted to, represents electric current I (tSAMP), and check and represent electric current I (tSAMP) whether be greater than and represent electric current I (t) and default
Reference current IREFConjunction.
Fig. 7 shows another fall off rate detector 130, can be used for secondary side controller 62, can differentiate fall off rate
RADROPWhether preset value RA is greater thanREF.Fig. 7 is similar with Fig. 6, wherein the same or similar element, can be said by previous
It is bright to learn, it is not repeated.It is that record is generated with digital latch 122 in Fig. 6, but different, the fall off rate detection in Fig. 7
Device 130 to provide a record, and is generated represent electric current I (t accordingly with the current mirror 132 of a deformationSAMP).As switch SWSAMP
When for short circuit, the current mirror 132 of deformation is general current mirror, and making the electric current on both sides is about 1:1.As switch SWSAMPTo open
Lu Shi, the capacitor C in the current mirror 132 of deformationGThe grid voltage on PMOS transistor MP1 is had recorded, so maintaining representative
Electric current I (tSAMP).Wherein, time point t hereSAMPFor sampling clock CKT/HMake switch SWSAMPBecome the time of open circuit from short circuit
Point.Refering to Fig. 4, Fig. 6 to relevant introduction it is found that the fall off rate detector 130 in Fig. 7 can differentiate fall off rate RADROP
Whether preset value RA is greater thanREF。
Fig. 8 shows another fall off rate detector 140, can be used for secondary side controller 62, can differentiate fall off rate
RADROPWhether preset value RA is greater thanREF.Fig. 8 is similar with Fig. 6, Fig. 7, wherein the same or similar element, it can be by previous
Explanation learn, be not repeated.Voltage-current conversion circuit 112 generates together with current mirror 144 and represents electric current I (t).When sampling
Clock CKT/HCapacitor C when " 1 " logically becomes " 0 ", in current memory 142MStore the grid voltage of PMOS instantly.
As sampling clock CKT/HIt is retention time T when for " 0 " in logicHOLD, PMOS provides representative according to grid voltage thereon
Electric current I (tSAMP).By combining data detection end MERG voltage, the inspection of resolver 126 represents electric current I (tSAMP) whether be greater than represent electricity
Flow I (t) and preset reference electric current IREFConjunction.If it does, resolver 126 can make wake-up signal SWAKEUPEnable, otherwise meeting
Make wake-up signal SWAKEUPForbidden energy.The fall off rate detector 140 it is found that in Fig. 8 is instructed to relevant refering to Fig. 4, Fig. 6, Fig. 7
It can differentiate fall off rate RADROPWhether preset value RA is greater thanREF。
Secondary side controller in some embodiments of the present invention can differentiate output voltage VOUTFall off rate RADROP
Whether preset value RA is greater thanREF.If fall off rate RADROPGreater than preset value RAREF, secondary-side control circuitry can provide information
To the primary side control circuit, it is made to start a switch periods, detect as quickly as possible and calibrates output voltage VBUS.In this way, of the invention
Some embodiments can no idling when overloaded, prevent output voltage VBUSThe too low event of decline occurs.
The foregoing is merely presently preferred embodiments of the present invention, all equivalent changes done according to the claims in the present invention with repair
Decorations, are all covered by the present invention.
Claims (12)
1. a kind of power supply unit has the primary side and a primary side of isolation, which includes:
One primary side control circuit is set to the primary side, and controls a power switch, will be located at an input electricity of the primary side
Source, is converted to the out-put supply positioned at the primary side, which has an output voltage；And
One secondary-side control circuitry, being set to the primary side to detect the output voltage can detect a decline of the output voltage
Rate, wherein when the fall off rate is greater than a predetermined value, which can provide information to the primary side control
Circuit processed；
Wherein, when the primary side control circuit receives the information, which starts a switch periods, to lead to
An inductance element is crossed, the output voltage is detected and calibrate,
Wherein, which includes first and second Voltage-current conversion circuit, wherein when first and second voltage
When turning the tracking of one of current circuit and converting the output voltage and represent electric current into one first, which turns electric
Current circuit another holding one therein records and generates one second and represent electric current, and when first and second is represented between electric current for this
When difference meets a preset condition, a consequential signal is generated, is considered as the fall off rate greater than the predetermined value.
2. power supply unit according to claim 1, wherein the inductance element is stored up in an opening time from the input power
Energy is deposited, is released energy in a discharge time, which only examines in the time of having a rest after the discharge time
It surveys the fall off rate and the switch periods includes the opening time, the discharge time and the time of having a rest.
3. power supply unit according to claim 1, wherein the secondary-side control circuitry also detects the output voltage, when
When the output voltage is lower than a preset voltage value, which just can provide the information.
4. power supply unit according to claim 1, wherein the secondary-side control circuitry also detects a switching frequency, is
The inverse of the switch periods, the secondary-side control circuitry just can detect the lower reduction of speed when switching frequency is lower than a predeterminated frequency
Rate.
5. power supply unit according to claim 1, wherein first and second Voltage-current conversion circuit alternately tracks
And converting the output voltage is that this first represents electric current.
6. a kind of power supply unit has the primary side and a primary side of isolation, which includes:
One primary side control circuit is set to the primary side, and controls a power switch, will be located at an input electricity of the primary side
Source, is converted to the out-put supply positioned at the primary side, which has an output voltage；And
One secondary-side control circuitry, being set to the primary side to detect the output voltage can detect a decline of the output voltage
Rate, wherein when the fall off rate is greater than a predetermined value, which can provide information to the primary side control
Circuit processed；
Wherein, when the primary side control circuit receives the information, which starts a switch periods, to lead to
An inductance element is crossed, the output voltage is detected and calibrate,
Wherein, which includes:
One logger keeps a record, corresponds to the output voltage in a first time；
The output voltage is converted to one first and represents electric current by one Voltage-current conversion circuit；
The record is converted to one second and represents electric current by one electric current identifier, is compared this and first second is represented electric current with this, and
When this first with this second represent difference between currents and meet a preset condition when, generate a consequential signal, it is big to be considered as the fall off rate
In the predetermined value.
7. power supply unit according to claim 6, wherein the inductance element is stored up in an opening time from the input power
Energy is deposited, is released energy in a discharge time, which only examines in the time of having a rest after the discharge time
It surveys the fall off rate and the switch periods includes the opening time, the discharge time and the time of having a rest.
8. power supply unit according to claim 6, wherein the secondary-side control circuitry also detects the output voltage, when
When the output voltage is lower than a preset voltage value, which just can provide the information.
9. power supply unit according to claim 6, wherein the secondary-side control circuitry also detects a switching frequency, is
The inverse of the switch periods, the secondary-side control circuitry just can detect the lower reduction of speed when switching frequency is lower than a predeterminated frequency
Rate.
10. power supply unit according to claim 6, wherein the secondary-side control circuitry is provided according to the output voltage
One third represents electric current and the logger as an analog-digital converter, which is represented electric current and is converted to a number letter
Number, and when the first time, the digital signal is latched, as the record.
11. power supply unit according to claim 6, wherein the logger includes a track and hold circuit, can be kept
A grid voltage on one control grid of one current mirror, as the record.
12. power supply unit according to claim 6, wherein when this first represent electric current and a predetermined current and, it is low
In this second represent electric current when, generate the consequential signal.
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| CN201510960027.XA CN106899217B (en) | 2015-12-18 | 2015-12-18 | The switch type power supplying device of fast load transient reaction |
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| CN103427634A (en) * | 2012-05-24 | 2013-12-04 | 立锜科技股份有限公司 | Fixed working time mode power supply for improving load transient state and method thereof |
| CN103532350A (en) * | 2012-08-06 | 2014-01-22 | 崇贸科技股份有限公司 | Control circuit with fast dynamic response for power converters |
| CN103580486A (en) * | 2012-07-31 | 2014-02-12 | 艾沃特有限公司 | Switching power converter dynamic load detection |
| CN104242655A (en) * | 2013-06-11 | 2014-12-24 | 戴乐格半导体公司 | Switching power converter with primary-side dynamic load detection and primary-side feedback and control |
| CN104300793A (en) * | 2014-07-17 | 2015-01-21 | 矽力杰半导体技术(杭州)有限公司 | Control method and control circuit for improving load dynamic response and switching power supply |
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| US9088247B2 (en) * | 2013-02-15 | 2015-07-21 | St-Ericsson Sa | Method and apparatus for a multi-standard, multi-mode, dynamic, DC-DC converter for radio frequency power amplifiers |
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| CN103427634A (en) * | 2012-05-24 | 2013-12-04 | 立锜科技股份有限公司 | Fixed working time mode power supply for improving load transient state and method thereof |
| CN103580486A (en) * | 2012-07-31 | 2014-02-12 | 艾沃特有限公司 | Switching power converter dynamic load detection |
| CN103532350A (en) * | 2012-08-06 | 2014-01-22 | 崇贸科技股份有限公司 | Control circuit with fast dynamic response for power converters |
| CN104242655A (en) * | 2013-06-11 | 2014-12-24 | 戴乐格半导体公司 | Switching power converter with primary-side dynamic load detection and primary-side feedback and control |
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