CN207910684U - Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply - Google Patents
Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply Download PDFInfo
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- CN207910684U CN207910684U CN201820224075.1U CN201820224075U CN207910684U CN 207910684 U CN207910684 U CN 207910684U CN 201820224075 U CN201820224075 U CN 201820224075U CN 207910684 U CN207910684 U CN 207910684U
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Abstract
The utility model provides a kind of adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply, including：Input rectifying filter circuit, Switching Power Supply control unit, transformer T206, output rectifier and filter, output feedback circuit, power tube N1, primary current sampling resistor Rcs；The positive output termination transformer T206 primary side winding different names end of input rectifying filter circuit, negative output is with terminating primary side；The current input terminal of transformer T206 primary side windings termination power tube N1 of the same name, the current output terminal of power tube N1 connect the one end primary current sampling resistor Rcs, another termination primary sides of primary current sampling resistor Rcs；One end in-phase input end connection primary current sampling resistor Rcs of peak point current comparator U230；The switch control terminal of the output termination power tube N1 of driving circuit U231；The vice-side winding of transformer T206 connects output rectifier and filter；The circuit avoid caused by sampling error switching frequency change it is excessive due to cause transformer to be generated by vibration abnormal sound problem.
Description
Technical field
The utility model belongs to integrated circuit fields；More specifically, the utility model provides a kind of novel quasi-resonance
The adaptive the lowest point lock-in circuit of Switching Power Supply more particularly to inverse-excitation type switch power-supply control technology.
Background technology
With the implementation of new Energy Efficiency Standard and the continuous promotion of electronic product performance, transfer efficiency, work(to Switching Power Supply
Rate density is put forward higher requirements, and more and more harsh to the control of the system cost of Switching Power Supply, therefore improves Switching Power Supply
Transfer efficiency cannot be implemented simply by increasing the modes such as cost.Generally start to use quasi-resonance valley conduction currently on the market
Technology reduces switching loss of the power tube in switching process, improves the transfer efficiency of system, reduces system Wen Sheng, improves production
The reliability etc. of product.
However quasi-resonance valley conduction technology itself is easy to cause the abnormal sound generated because transformer vibrates there is also defect
The problems such as phenomenon or EMI performances practical variation.Switching frequency is discontinuous when problem above is primarily due to valley conduction
, and amplitude is excessive to be caused since sampling deviation leads to problems such as the lowest point switch.Quasi-resonance the lowest point skill is used currently on the market
The product generally existing above problem of art.
It is high to adapt to Switching Power Supply high-frequency small size because switching loss can be greatly reduced for quasi-resonance valley conduction technology
The development trend of power density, the following mainstream control technology that will become Switching Power Supply, therefore quasi-resonance valley conduction technology
Itself existing defect has to solve.
Invention content
The purpose of the utility model is to overcome the deficiencies in the prior art, provide a kind of Quasi-resonant switching power supply from
Adapt to the lowest point lock-in circuit, solve Quasi-resonant switching power supply due to when the lowest point switch switching frequency change it is excessive and lead to transformation
The abnormal sound problem that device is generated by vibration.The technical solution adopted in the utility model is：
A kind of Switching Power Supply control unit, including：
Sampling and keep module U221, error amplifier U223, saw-toothed wave generator U224, PWM comparator U225, quasi-resonance
The lowest point comparator U242, NOT gate U243, nor gate U227, the lowest point locking enable module U229, the lowest point locking module U228, switch
Latch U232, driving circuit U231, peak point current comparator U230；
The input terminal of sampling and keep module U221, the in-phase input end of quasi-resonance the lowest point comparator U242 are auxiliary for connecing respectively
Winding is helped to divide feedback signal；The inverting input of the output termination error amplifier U223 of sampling and keep module U221, error
The in-phase input end reference voltage signal V of amplifier U223th_FB；The output signal Comp of error amplifier U223 meets PWM and compares
The inverting input of device U225, the output of saw-toothed wave generator U224 connect the in-phase input end of PWM comparators U225；PWM compares
An input terminal of the output termination nor gate U227 of device U225；
The anti-phase input of quasi-resonance the lowest point comparator U242 terminates the lowest point discrimination standard signal Vth_DEM；Quasi-resonance the lowest point ratio
Another input terminal of output termination nor gate U227 compared with device U242 and the input terminal of NOT gate U243；Nor gate U227's is defeated
Go out, the output signal QR of NOT gate U243 inputs the lowest point locking module U228 respectively；
Error amplifier output signal Comp and power tube switching signal On inputs the lowest point locking and enables module U229 respectively,
The lowest point locking enables the lowest point locking enable signal LockEn that module U229 is generated and inputs the lowest point locking module U228；Power tube is opened
OFF signal On inputs the lowest point locking module U228；Trigger signal is connected in the power tube of the lowest point locking module U228 output ends output
The ends S of ONset input switch latch U232；It is rest-set flip-flop to switch latch U232, and the R of switch latch U232 terminates peak
It is worth the output end of current comparator U230；The in-phase input end of peak point current comparator U230 is for connecting primary current sampling electricity
The one end Rcs is hindered, anti-phase input terminates peak point current reference signal Vth_CS；
Switch the ends the Q output power pipe switching signal On of latch U232, power tube switching signal On input driving circuits
The input terminal of U231, the output end of driving circuit U231 are used to connect the switch control terminal of power tube N1.
Further, locking enabled module U229 in the lowest point includes：MOS switch K321, K322, phase inverter U313, capacitance
C323, C324, isolation buffer amplifier U331, positive voltage bias V332, negative voltage bias V333, hysteresis comparator U334,
U335, nor gate U336, counter U337；
Power tube switching signal On connects the input terminal of the control terminal and phase inverter U313 of MOS switch K321；Error amplifier
The output signal Comp of U223 connects one end of MOS switch K321, one end of another termination MOS switch K322 of MOS switch K321,
And it is grounded by capacitance C323；The control terminal of the output termination MOS switch K322 of phase inverter U313, MOS switch K322's is another
The input terminal of isolation buffer amplifier U331 is terminated, and is grounded by capacitance C324；
The output end of isolation buffer amplifier U331 connects the anti-of hysteresis comparator U334 by positive voltage bias V332 respectively
Xiang Duan connects the in-phase end of hysteresis comparator U335 by negative voltage bias V333；The in-phase end of hysteresis comparator U334 connects error
The output signal Comp of amplifier U223；The output signal of the reverse phase termination error amplifier U223 of hysteresis comparator U335
Comp；The output end of hysteresis comparator U334, U335 connect two input terminals of nor gate U336 respectively；The output of nor gate U336
Meet the reset terminal of counter U337, the clock termination power tube switching signal On of counter U337；The output end of counter U337
Export the lowest point locking enable signal LockEn.
Further, the lowest point locking enable signal LockEn also controls of input hysteresis comparator U334, U335 respectively
End, when LockEn signals is high level, to increase the sluggish section of hysteresis comparator U334, U335.
Further, locking module U228 in the lowest point includes：D type flip flop U411, counter U415, counter U416, number
Comparator U417, selector U418 and nor gate U412, U413, NOT gate U414；
D type flip flop U411 clocks terminate the output signal PWM of nor gate U227；The lowest point locks enable signal LockEn difference
Connect the reset terminal of the reset terminal and counter U415 of d type flip flop U411；The D of d type flip flop U411 terminates high level；
The Q output of d type flip flop U411 connects an input terminal of nor gate U412 and the selection control terminal of selector U418；
The Q output of d type flip flop U411 connects an input terminal of nor gate U413；Another input termination of nor gate U412 and U413
The output signal QR of NOT gate U243；The clock end of the output termination counter U415 of nor gate U412, the output of nor gate U413
Terminate the clock end of counter U146；Power tube switching signal On connects the input terminal of NOT gate U414, the output termination of NOT gate U414
The reset terminal of counter U416；The output end of counter U415 and U416 connect two input terminals of digital comparator U417 respectively；
The output end of digital comparator U417 and the output signal PWM of nor gate U227 connect two input terminals of selector U418 respectively；
The output end output power pipe conducting trigger signal ONset of selector U148.
A kind of adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply, including：
Input rectifying filter circuit, above-mentioned Switching Power Supply control unit, transformer T206, output rectifier and filter,
Export feedback circuit, power tube N1, primary current sampling resistor Rcs；
The positive output termination transformer T206 primary side winding different names end of input rectifying filter circuit, negative output terminate primary side
Ground；
The current input terminal of transformer T206 primary side windings termination power tube N1 of the same name, the current output terminal of power tube N1 connect
The one end primary current sampling resistor Rcs, another termination primary sides of primary current sampling resistor Rcs；
One end in-phase input end connection primary current sampling resistor Rcs of peak point current comparator U230；Driving circuit
The switch control terminal of the output termination power tube N1 of U231；
The vice-side winding of transformer T206 connects output rectifier and filter, and direct current is exported by output rectifier and filter
Pressure；
Output feedback circuit includes the output feedback auxiliary winding of transformer T206, the both ends connection of output feedback auxiliary winding
Concatenated resistance R1, R2；Auxiliary winding, which is obtained, from series resistance R1, R2 tie point divides feedback signal；Auxiliary winding partial pressure is anti-
Feedback signal connects the in-phase input end of the input terminal of sampling and keep module U221, quasi-resonance the lowest point comparator U242.
The utility model has the advantage of：The utility model obtains average resonance the lowest point number by integral process, with this
To be connected with reference to prejudge and control next Cyclical power pipe, to avoid the switching frequency caused by sampling error from changing
The abnormal sound problem for causing transformer to be generated by vibration greatly.
Description of the drawings
Fig. 1 is the adaptive valley conduction schematic diagram of quasi-resonance of the utility model.
Fig. 2 is the adaptive the lowest point lock-in circuit schematic diagram of Quasi-resonant switching power supply of the utility model.
Fig. 3 is that the lowest point locking of the utility model enables inside modules schematic diagram.
Fig. 4 is schematic diagram inside the lowest point locking module of the utility model.
Specific implementation mode
With reference to specific drawings and examples, the utility model is described in further detail.
The utility model provides a kind of adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply, as shown in Fig. 2, including：
Input rectifying filter circuit, Switching Power Supply control unit 220, transformer T206, output rectifier and filter 207,
Export feedback circuit 208, power tube N1, primary current sampling resistor Rcs；
Wherein, Switching Power Supply control unit 220 is the core of the utility model, including：Sampling and keep module U221, error
Amplifier U223, saw-toothed wave generator U224, PWM comparator U225, quasi-resonance the lowest point comparator U242, NOT gate U243 or non-
Door U227, the lowest point locking enable module U229, the lowest point locking module U228, switch latch U232, driving circuit U231, peak value
Current comparator U230；Wherein the conducting of power tube N1 is controlled by the output signal of the lowest point locking module U228, power tube N1's
Shutdown is controlled by the output signal of peak point current comparator U230；
Input rectifying filter circuit includes the bridge rectifier that diode D201~D204 is constituted, filter capacitor C205；
The positive output termination transformer T206 primary side winding different names end of input rectifying filter circuit, negative output is with terminating primary side；
The current input terminal of transformer T206 primary side windings termination power tube N1 of the same name, the current output terminal of power tube N1 connect
The one end primary current sampling resistor Rcs, another termination primary sides of primary current sampling resistor Rcs；NMOS can be used in power tube N1
Pipe, drain electrode, source electrode are respectively as current input terminal and current output terminal, and grid is as switch control terminal；
The vice-side winding of transformer T206 connects output rectifier and filter 207, is exported by output rectifier and filter 207
DC voltage；Output rectifier and filter 207 may include rectifier diode, filter capacitor, output resistance etc., this part is existing
The custom circuit for having technology, repeats no more；
It exports the output that feedback circuit 208 includes transformer T206 and feeds back auxiliary winding, output feedback auxiliary winding both ends
Connect concatenated resistance R1, R2；Auxiliary winding, which is obtained, from series resistance R1, R2 tie point divides feedback signal 110；
The input terminal of sampling and keep module U221, the in-phase input end of quasi-resonance the lowest point comparator U242 connect respectively auxiliary around
Group partial pressure feedback signal 110；The inverting input of the output termination error amplifier U223 of sampling and keep module U221, error are put
The in-phase input end reference voltage signal V of big device U223th_FB；The output signal Comp of error amplifier U223 connects PWM comparators
The inverting input of U225, the output of saw-toothed wave generator U224 connect the in-phase input end of PWM comparators U225；PWM comparators
An input terminal of the output termination nor gate U227 of U225；
The anti-phase input of quasi-resonance the lowest point comparator U242 terminates the lowest point discrimination standard signal Vth_DEM；Quasi-resonance the lowest point ratio
Another input terminal of output termination nor gate U227 compared with device U242 and the input terminal of NOT gate U243；Nor gate U227's is defeated
Go out, the output signal QR of NOT gate U243 inputs the lowest point locking module U228 respectively；
Error amplifier output signal Comp and power tube switching signal On inputs the lowest point locking and enables module U229 respectively,
The lowest point locking enables the lowest point locking enable signal LockEn that module U229 is generated and inputs the lowest point locking module U228；Power tube is opened
OFF signal On inputs the lowest point locking module U228；Trigger signal is connected in the power tube of the lowest point locking module U228 output ends output
The ends S of ONset input switch latch U232；It is rest-set flip-flop to switch latch U232, and the R of switch latch U232 terminates peak
It is worth the output end of current comparator U230；The in-phase input end of peak point current comparator U230 connects primary current sampling resistor
The one end Rcs, anti-phase input terminate peak point current reference signal Vth_CS；
The ends the Q output power pipe switching signal On for switching latch U232, power tube is added to by driving circuit U231
The switch control terminal of N1；
Fig. 1 is the adaptive valley conduction schematic diagram of quasi-resonance.Auxiliary winding divides feedback signal 110 after over-sampling is kept
An input signal as error amplifier U223；The output signal 120 of saw-toothed wave generator is as PWM comparators U225's
One input signal, the output signal Comp of error amplifier work as letter as another input signal of PWM comparators U225
After numbers 120 intersect with signal Comp, PWM comparator U225 output signals are lower to form signal 141 from height, and signal 141 and standard are humorous
It shakes after the combination of output signal 150 of the lowest point comparator U242, trigger signal ONset is connected for constituting power tube.
When signal ONset is by low get higher, sawtooth signal 120 is immediately returned to original state and prepares to generate next week
The output signal of the sawtooth signal of phase, PWM comparators U225 inverts, shape at once also with the variation of sawtooth signal 120
At a negative burst pulse, as shown in the signal 141 in Fig. 1.
When the sampling of feedback signal FB, that is, auxiliary winding partial pressure feedback signal 110 is there are when deviation, which also will
It is amplified by error amplifier U223, causes the output valve of error amplifier U223 to deviate, such as signal 131 and signal in Fig. 1
Shown in 133, this can lead to the variation of PWM comparator U225 output signals position, as shown in signal 142,143 in Fig. 1, and cause
The offset of power tube open signal, as shown in signal 162 and signal 163.And power tube open signal when being normal of signal 161.
111 correspondence system switching frequency average value of signal, when resonance the lowest point open signal 112 and 113 is relative to signal 111
When changing bigger, indicate that the frequency of Switching Power Supply changes greatly, this is easy to cause the abnormal sound problem generated by oscillating transformers.
The utility model filters out the amplifier caused by sampling error by being integrated to the output of error amplifier
Error component, acquires error amplifier output average value, which corresponds to switching frequency average value.In the defeated of error amplifier
Go out on average value to be superimposed positive and negative two offsets and form voltage window, is compared with the output instantaneous flow of error amplifier, when
The output instantaneous flow of error amplifier falls within the scope of above-mentioned voltage window and continuously keeps several switch periods, system to start to open
Dynamic the lowest point locking mode simultaneously increases above-mentioned voltage window range, avoids leading to the lowest point locking unlock because of false triggering.When error is put
The output instantaneous flow of big device is more than above-mentioned increased voltage window range, and the lowest point locking unlocks, and system restarts the lowest point lock
Determine process.
By the primary side winding of transformer T206 and the coil coupled relation of auxiliary winding, in transformer demagnetization phase, from
Auxiliary winding coil is sampled to obtain auxiliary winding partial pressure feedback signal 110 and be kept；Sampling keeps signal as error amplifier
The negative-feedback of U223 inputs, and sampling keeps signal and reference voltage signal Vth_FBAfter error amplifier U223 amplifications, output
Error signal realizes loop adjustment automatically, and when output error signal is got higher, expression output loading aggravates, and works as output error signal
It is lower, indicates that output loading lightens.
The output signal Comp of error amplifier U223 is compared with the sawtooth signal that saw-toothed wave generator generates is by PWM
Device U225 is modulated, and is generated pwm signal and is input to the lowest point locking module U228；Quasi-resonance the lowest point comparator is by comparing auxiliary
Winding divides feedback signal 110 and the lowest point discrimination standard signal Vth_DEM, export resonance the lowest point signal, as the lowest point locking module
Another input；
The lowest point locking enables module U229 by being integrated to the output of error amplifier U223, filters out because of sampling error
Caused by amplifier error output component, acquire the output average value of error amplifier.In the output of error amplifier U223
It is superimposed positive and negative two offsets on average value and forms voltage window, is compared with the output instantaneous flow of error amplifier U223,
When the output instantaneous flow of error amplifier U223 is fallen within the scope of above-mentioned voltage window and continuously keeps several switch periods, the lowest point
Locking enables module output the lowest point and latches enable signal LockEn and increase above-mentioned voltage window range, as error amplifier U223
Output instantaneous flow be more than increased above-mentioned voltage window range, the lowest point locking unlock, system restarts the lowest point and locked
Journey.
The lowest point locking module U228 latches the resonance the lowest point number average corresponding to error amplifier output integration amount, makees
Refer to comparison signal for one of digital comparator, the output with another the lowest point real-time counter (following counter U416) into
Row compares, which can reset counts again, when the counting week of another the lowest point real-time counter
When phase reaches the lowest point number average being latched, digital comparator will export next period conducting trigger signal, accurate at this time humorous
The adaptive the lowest point of Switching Power Supply of shaking is locked.
The output signal setting switch latch U232 of the lowest point locking module U228, the conducting of control power tube N1, this is opened
The reset signal for shutting storage U232 is the output of peak point current comparator U230, and power tube N1 is turned off after reset.
Pressure drops and peak current threshold voltage of the peak point current comparator U230 by comparing power pipe end sampling resistor Rcs
Size, output high level signal carry out reset switch latch U232, control the shutdown of power tube.
Module U229, the lowest point locking module are enabled to the specific course of work of the utility model and the lowest point locking below
The realization of U228 is described in detail；
Enter off-phases after power tube N1 is connected, transformer T206 enters demagnetization process, sampling and keep module
U221 sampling auxiliary winding partial pressure feedback signals 110 simultaneously preserve, and as an input signal of error amplifier U223, error is put
Another input signal of big device U223 is reference voltage signal Vth_FB；Sampling keeps signal and reference voltage signal Vth_FB's
For difference after error amplifier U223 amplifications, output signal Comp is connected to an input terminal of PWM comparators U225；
Another input signal of PWM comparators U225 is to connect the output of saw-toothed wave generator U224；With error amplifier
The output signal Comp of U223 is compared, and exports one of switch control signal；
Another switch control signal is generated by quasi-resonance the lowest point comparator U242, and the one of quasi-resonance the lowest point comparator U242
A input termination auxiliary winding divides feedback signal 110, another input termination the lowest point discrimination standard signal Vth_DEM.Quasi-resonance
Synchronizing signal of the output signal of the lowest point comparator U242 as power tube valley conduction, the output with PWM comparators U225 are believed
Number by being input to the lowest point locking module U228 after nor gate U227 combination.
The lowest point locking enables module U229 and calculates switching frequency average value in real time, is obtained when switching frequency mean value calculation
When error is less than setting range, the lowest point locking enables module U229 outputs the lowest point and locks enable signal, controls the lowest point locking module
U228 enters frequency lock procedure；
After locking enabled module U229 in the lowest point sends out the lowest point locking enable signal, the lowest point locking module 228 is first calculated and is protected
The resonance the lowest point periodicity corresponding to switching frequency average value is deposited, digital comparator is connected to as resonance the lowest point number average
One input terminal.Another input termination the lowest point real-time counter of digital comparator, the lowest point real-time counter is at each
It can all be counted again in switch periods, the lowest point real-time counter automatic clear when power tube is connected is humorous after demagnetization
It is started counting up during shaking.When the lowest point, real-time counter count value reaches resonance the lowest point number average, digital comparator will
High level signal is exported to trigger the conducting of power tube.
Before the lowest point locks, the output and quasi-resonance paddy of the conducting trigger signal of power tube N1 by PWM comparators U225
Bottom comparator U242 output combination controls.
The cut-off signals of power tube N1 are generated by peak point current comparator U230；After power tube N1 conductings, primary side inductance
Into excited state, inductive current is continuously increased, when pressure drop of the inductive current on sampling resistor Rcs is more than peak point current benchmark
Signal Vth_CSWhen, peak point current comparator U230 exports high level, and switch register U232 is reset, power tube N1 shutdowns.
The lowest point locking enables the electric principle of module U229 referring to Fig. 3；Including：MOS switch K321, K322, phase inverter U313,
Capacitance C323, C324, isolation buffer amplifier U331, positive voltage bias V332, negative voltage bias V333, hysteresis comparator
U334, U335, nor gate U336, counter U337；
Power tube switching signal On connects the input terminal of the control terminal and phase inverter U313 of MOS switch K321；Error amplifier
The output signal Comp of U223 connects one end of MOS switch K321, one end of another termination MOS switch K322 of MOS switch K321,
And it is grounded by capacitance C323；The control terminal of the output termination MOS switch K322 of phase inverter U313, MOS switch K322's is another
The input terminal of isolation buffer amplifier U331 is terminated, and is grounded by capacitance C324；
The output end of isolation buffer amplifier U331 connects the anti-of hysteresis comparator U334 by positive voltage bias V332 respectively
Xiang Duan connects the in-phase end of hysteresis comparator U335 by negative voltage bias V333；The in-phase end of hysteresis comparator U334 connects error
The output signal Comp of amplifier U223；The output signal of the reverse phase termination error amplifier U223 of hysteresis comparator U335
Comp；The output end of hysteresis comparator U334, U335 connect two input terminals of nor gate U336 respectively；The output of nor gate U336
Meet the reset terminal of counter U337, the clock termination power tube switching signal On of counter U337；The output end of counter U337
Export the lowest point locking enable signal LockEn；
More preferably, locking enable signal LockEn in the lowest point also inputs the control terminal of hysteresis comparator U334, U335 respectively, with
When LockEn signals are high level, increase the sluggish section of hysteresis comparator U334, U335；
Signal Comp is the output of error amplifier U223, and signal On is the signal for controlling power tube switch, phase inverter
U313, MOS switch K321, K322 and capacitance C323 and C324 constitute low frequency integrating circuit.Each switching process, error
The output signal Comp of amplifier U223 transmits primary, the frequency characteristic of low frequency integrating circuit to capacitance C324 by capacitance C323
Proportionate relationship depending on switching frequency and capacitance C323 and capacitance C324.After system switching is stablized, the voltage on capacitance C324
The as average value of the output signal Comp of error amplifier U223.
Isolation buffer amplifier U331 and positive voltage bias V332, negative voltage bias V333 are constituted centered on integral voltage
Voltage window, the reference voltage as hysteresis comparator U334 and U335.Another of hysteresis comparator U334 and U335 are defeated
Enter the output signal Comp that signal is error amplifier.When the signal Comp of error amplifier is fallen centered on by integral voltage
Within the scope of voltage window, nor gate U336 exports a high level signal, and counter U337 starts to calculate, if nor gate U336
High level is exported in continuous 32 switch periods, the LockEn signals of counter U337 outputs are high level signal, indicate the lowest point
Locking module U228 work.
When LockEn signals are high level, increase the sluggish section of hysteresis comparator U334, U335, to increase integral electricity
Voltage window range centered on pressure prevents false triggering and leads to the lowest point locking unlock.
The electric principle of the lowest point locking module U228 participates in Fig. 4, including：D type flip flop U411, counter U415, counter
U416, digital comparator U417, selector U418 and nor gate U412, U413, NOT gate U414；
D type flip flop U411 clocks terminate the output signal PWM of nor gate U227；The lowest point locks enable signal LockEn difference
Connect the reset terminal of the reset terminal and counter U415 of d type flip flop U411；The D of d type flip flop U411 terminates high level；
The Q output of d type flip flop U411 connects an input terminal of nor gate U412 and the selection control terminal of selector U418；
The Q output of d type flip flop U411 connects an input terminal of nor gate U413；Another input termination of nor gate U412 and U413
The output signal QR of NOT gate U243；The clock end of the output termination counter U415 of nor gate U412, the output of nor gate U413
Terminate the clock end of counter U146；Power tube switching signal On connects the input terminal of NOT gate U414, the output termination of NOT gate U414
The reset terminal of counter U416；The output end of counter U415 and U416 connect two input terminals of digital comparator U417 respectively；
The output end of digital comparator U417 and the output signal PWM of nor gate U227 connect two input terminals of selector U418 respectively；
The output end output power pipe conducting trigger signal ONset of selector U148；
When signal LockEn is low level, counter U415 has been at cleared condition, and d type flip flop U411 is reset.
After signal LockEn is got higher, counter U415 is started counting up, in signal PWM by the low rising edge got higher, D triggerings
The output signal 425 of device U411 becomes high level, and counter U415 stops counting and preserves count value, the counting of counter U415
It is worth a comparison reference 427 as digital comparator U417.
When power tube switching signal On is high level, counter U416 is reset；When power tube switching signal On is low electricity
Usually, and after the output signal of d type flip flop U411 425 becomes high level, counter U416 is started counting up, and counter U416's is defeated
Go out another fiducial value 428 as digital comparator U417.When fiducial value 428 is equal to 427, digital comparator U417 outputs
High level.
The output signal of selector U418 is selected by 425 low and high level of signal, when signal 425 is low level, or
The output signal PWM of NOT gate U227 is output to signal ONset, when signal 425 is high level, the output of digital comparator U417
Signal 429 is output to signal ONset.
Merely exemplary, the utility model has been applied to flyback power supply converter.It will be appreciated that this practicality is new
Type has wider application range.
It should be noted last that the above specific implementation mode is only to illustrate the technical solution of the utility model rather than limit
System, although the utility model is described in detail with reference to example, it will be understood by those of ordinary skill in the art that, it can be right
The technical solution of the utility model is modified or replaced equivalently, without departing from the spirit and model of technical solutions of the utility model
It encloses, should all cover in the right of the utility model.
Claims (5)
1. a kind of Switching Power Supply control unit, which is characterized in that including：
Sampling and keep module U221, error amplifier U223, saw-toothed wave generator U224, PWM comparator U225, quasi-resonance the lowest point
Comparator U242, NOT gate U243, nor gate U227, the lowest point locking enable module U229, the lowest point locking module U228, switch and latch
Device U232, driving circuit U231, peak point current comparator U230；
The input terminal of sampling and keep module U221, the in-phase input end of quasi-resonance the lowest point comparator U242 for connect respectively auxiliary around
Group partial pressure feedback signal (110)；The inverting input of the output termination error amplifier U223 of sampling and keep module U221, error
The in-phase input end reference voltage signal V of amplifier U223th_FB；The output signal Comp of error amplifier U223 meets PWM and compares
The inverting input of device U225, the output of saw-toothed wave generator U224 connect the in-phase input end of PWM comparators U225；PWM compares
An input terminal of the output termination nor gate U227 of device U225；
The anti-phase input of quasi-resonance the lowest point comparator U242 terminates the lowest point discrimination standard signal Vth_DEM；Quasi-resonance the lowest point comparator
Another input terminal of the output termination nor gate U227 of U242 and the input terminal of NOT gate U243；Nor gate U227's exports, is non-
The output signal QR of door U243 inputs the lowest point locking module U228 respectively；
Error amplifier output signal Comp and power tube switching signal On inputs the lowest point locking and enables module U229, the lowest point respectively
Locking enables the lowest point locking enable signal LockEn that module U229 is generated and inputs the lowest point locking module U228；Power tube switch letter
Number On inputs the lowest point locking module U228；The power tube conducting trigger signal ONset of the lowest point locking module U228 output ends output
The ends S of input switch latch U232；It is rest-set flip-flop, the R termination peak value electricity of switch latch U232 to switch latch U232
Flow the output end of comparator U230；The in-phase input end of peak point current comparator U230 is for connecting primary current sampling resistor
The one end Rcs, anti-phase input terminate peak point current reference signal Vth_CS；
Switch the ends the Q output power pipe switching signal On, power tube switching signal On input driving circuits U231 of latch U232
Input terminal, the output end of driving circuit U231 is used to connect the switch control terminal of power tube N1.
2. Switching Power Supply control unit as described in claim 1, which is characterized in that
The lowest point locking enables module U229：MOS switch K321, K322, phase inverter U313, capacitance C323, C324, isolation are slow
Rush amplifier U331, positive voltage bias V332, negative voltage bias V333, hysteresis comparator U334, U335, nor gate U336, meter
Number device U337；
Power tube switching signal On connects the input terminal of the control terminal and phase inverter U313 of MOS switch K321；Error amplifier U223
Output signal Comp connect one end of MOS switch K321, one end of another termination MOS switch K322 of MOS switch K321, and lead to
Cross capacitance C323 ground connection；The control terminal of the output termination MOS switch K322 of phase inverter U313, another termination of MOS switch K322
The input terminal of isolation buffer amplifier U331, and be grounded by capacitance C324；
The output end of isolation buffer amplifier U331 connects the reverse side of hysteresis comparator U334 by positive voltage bias V332 respectively,
The in-phase end of hysteresis comparator U335 is connect by negative voltage bias V333；The in-phase end of hysteresis comparator U334 connects error amplifier
The output signal Comp of U223；The output signal Comp of the reverse phase termination error amplifier U223 of hysteresis comparator U335；It is sluggish
The output end of comparator U334, U335 connect two input terminals of nor gate U336 respectively；The output of nor gate U336 connects counter
The reset terminal of U337, the clock termination power tube switching signal On of counter U337；The output end of counter U337 exports the lowest point
Lock enable signal LockEn.
3. Switching Power Supply control unit as claimed in claim 2, which is characterized in that
The lowest point locks the control terminal that enable signal LockEn also inputs hysteresis comparator U334, U335 respectively, to work as LockEn letters
When number being high level, increase the sluggish section of hysteresis comparator U334, U335.
4. Switching Power Supply control unit as described in claim 1, which is characterized in that
The lowest point locking module U228 includes：D type flip flop U411, counter U415, counter U416, digital comparator U417, choosing
Select device U418 and nor gate U412, U413, NOT gate U414；
D type flip flop U411 clocks terminate the output signal PWM of nor gate U227；The lowest point locking enable signal LockEn meets D respectively
The reset terminal of the reset terminal and counter U415 of trigger U411；The D of d type flip flop U411 terminates high level；
The Q output of d type flip flop U411 connects an input terminal of nor gate U412 and the selection control terminal of selector U418；D is touched
The Q output of hair device U411 connects an input terminal of nor gate U413；Another input termination of nor gate U412 and U413 are non-
The output signal QR of door U243；The clock end of the output termination counter U415 of nor gate U412, the output end of nor gate U413
Connect the clock end of counter U146；Power tube switching signal On connects the input terminal of NOT gate U414, the output termination meter of NOT gate U414
The reset terminal of number device U416；The output end of counter U415 and U416 connect two input terminals of digital comparator U417 respectively；Number
The output end of word comparator U417 and the output signal PWM of nor gate U227 connect two input terminals of selector U418 respectively；Choosing
Select the output end output power pipe conducting trigger signal ONset of device U148.
5. a kind of adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply, including：
Input rectifying filter circuit, Switching Power Supply control unit as described in any one of claims 1 to 4, transformer T206,
Output rectifier and filter (207), output feedback circuit (208), power tube N1, primary current sampling resistor Rcs；
The positive output termination transformer T206 primary side winding different names end of input rectifying filter circuit, negative output is with terminating primary side；
The current input terminal of transformer T206 primary side windings termination power tube N1 of the same name, the current output terminal of power tube N1 connect primary
The one end current sampling resistor Rcs, another termination primary sides of primary current sampling resistor Rcs；
One end in-phase input end connection primary current sampling resistor Rcs of peak point current comparator U230；Driving circuit U231's
The switch control terminal of output termination power tube N1；
The vice-side winding of transformer T206 connects output rectifier and filter (207), is exported by output rectifier and filter (207)
DC voltage；
Output feedback circuit (208) includes the output feedback auxiliary winding of transformer T206, and output feedback auxiliary winding both ends connect
Meet concatenated resistance R1, R2；Auxiliary winding partial pressure feedback signal (110) is obtained from series resistance R1, R2 tie point；Auxiliary winding
Partial pressure feedback signal (110) connects the in-phase input end of the input terminal of sampling and keep module U221, quasi-resonance the lowest point comparator U242.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820224075.1U CN207910684U (en) | 2018-02-08 | 2018-02-08 | Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820224075.1U CN207910684U (en) | 2018-02-08 | 2018-02-08 | Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply |
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| Publication Number | Publication Date |
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| CN207910684U true CN207910684U (en) | 2018-09-25 |
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|---|---|---|---|
| CN201820224075.1U Withdrawn - After Issue CN207910684U (en) | 2018-02-08 | 2018-02-08 | Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108173435A (en) * | 2018-02-08 | 2018-06-15 | 无锡硅动力微电子股份有限公司 | Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply |
| CN111884494A (en) * | 2020-07-23 | 2020-11-03 | 成都启臣微电子股份有限公司 | Quasi-resonance valley bottom conduction circuit with compensation function |
| TWI748876B (en) * | 2020-12-28 | 2021-12-01 | 大陸商昂寶電子（上海）有限公司 | Device and method for valley bottom locking in quasi-resonant switching power supply |
-
2018
- 2018-02-08 CN CN201820224075.1U patent/CN207910684U/en not_active Withdrawn - After Issue
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108173435A (en) * | 2018-02-08 | 2018-06-15 | 无锡硅动力微电子股份有限公司 | Switching Power Supply control unit and the adaptive the lowest point lock-in circuit of Quasi-resonant switching power supply |
| CN108173435B (en) * | 2018-02-08 | 2023-08-15 | 无锡硅动力微电子股份有限公司 | Switch power supply control unit and quasi-resonant switch power supply self-adaptive valley locking circuit |
| CN111884494A (en) * | 2020-07-23 | 2020-11-03 | 成都启臣微电子股份有限公司 | Quasi-resonance valley bottom conduction circuit with compensation function |
| TWI748876B (en) * | 2020-12-28 | 2021-12-01 | 大陸商昂寶電子（上海）有限公司 | Device and method for valley bottom locking in quasi-resonant switching power supply |
| US11901813B2 (en) | 2020-12-28 | 2024-02-13 | On-Bright Electronics (Shanghai) Co., Ltd. | Systems and methods for valley locking related to quasi-resonant switching power supplies |
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