CN207460000U - A kind of two-mode field circuit of PWM/PFM - Google Patents
A kind of two-mode field circuit of PWM/PFM Download PDFInfo
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- CN207460000U CN207460000U CN201721355602.4U CN201721355602U CN207460000U CN 207460000 U CN207460000 U CN 207460000U CN 201721355602 U CN201721355602 U CN 201721355602U CN 207460000 U CN207460000 U CN 207460000U
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Abstract
The utility model discloses the two-mode field circuit of PWM/PFM a kind of, including mode selection module, PWM control modules, PFM control modules and oscillation module；The input terminal of the mode selection module connects the input terminal of the two-mode field circuit, and the output terminal of the mode selection module connects the control terminal of the PWM control modules and the control terminal of the PFM control modules simultaneously；The output terminal of the PWM control modules is connected with the control terminal of the oscillation module；The input terminal of the PFM control modules connects the input terminal of the two-mode field circuit, and the output terminal of the PFM control modules is connected with the control terminal of the oscillation module；The output terminal of the oscillation module is connected with the output terminal of the two-mode field circuit, for generating and exporting oscillating voltage.The loss of function module can be effectively reduced, improves the efficiency under system full-load current.
Description
Technical field
The utility model is related to the two-mode field of DC-DC converter control circuit more particularly to a kind of PWM/PFM electricity
Road.
Background technology
For pulse width modulation (PWM) type dc-dc since its output ripple is small, collocation structure is simple, steady
It is qualitative it is good generally adopted in power management chip with low noise advantages, but in practical applications it has been found that
As load is gradually reduced, total power consumption ratio improves shared by conduction loss and switching loss in system, i.e. system transfer efficiency drop
Low, then simple pwm pattern can not meet the high efficiency needed for underloading conditional systems.Then there has been proposed pulse frequencies
Rate modulation system (PFM), this mode can reduce the switching frequency of system at light load, be effectively improved the underloading of system
Efficiency.
There are many kinds of the specific implementations controlled on PFM, and earliest there is hysteresis voltage type PFM, basis is set
The bound threshold value of output voltage is determined to control the stabilization of output voltage, but inductive current size is but unable to control, then people
Again invented sluggish current mode PFM control models, this pattern can set the upper limit threshold of sample rate current to limit inductance
Current peak, it is ensured that system is not at over-current state.The later limit of output voltage ripple and inductive current peak in order to balance
System is that set inductance is adopted there has been proposed peak point current restricted type PFM, but for the shortcomings that this one maximum of pattern
Sample voltage max is fixed, then may result in output ripple and changes with load current size variation, and is exported greatly
Ripple may result in decrease in efficiency.For this problem, self-adaptive current type restricted type PFM and dynamic inductance energy stores
Technology is just come into being, both technologies can obtain the adaptive adjustment of inductive current by adaptive feedback circuit, inhibit
Excessive output ripple, it is ensured that the Effec-tive Function of the system under underloading.
Then for the system high efficiency obtained under full load condition, people begin to use PWM/PFM double mode technology controls
DC-DC cyclic systems processed so that system in PWM mode, is operated in PFM patterns at light load in heavy duty work.A kind of traditional reality
Such as shown in Fig. 1, it can be seen that as load increases, error operational amplifier output voltage Vin also follows increase in system major loop, in
It is that can operating mode be selected according to Vin sizes, but PWM mode and PFM patterns are mutual indepedent in this example, and there are three for system
A comparator, two rest-set flip-flops, an oscillator and a PWM/PFM control circuit, so system structure is complicated, bring
Quiescent dissipation is big.
Utility model content
The purpose of the utility model embodiment is to provide the two-mode field circuit of PWM/PFM a kind of, can effectively reduce work(
The loss of energy module, improves the efficiency under system full-load current.
To achieve the above object, the utility model embodiment provides the two-mode field circuit of PWM/PFM a kind of, including
Mode selection module, PWM control modules, PFM control modules and oscillation module；The input terminal connection institute of the mode selection module
The input terminal of two-mode field circuit is stated, the output terminal of the mode selection module connects the control of the PWM control modules simultaneously
End processed and the control terminal of the PFM control modules；The output terminal of the PWM control modules connects with the control terminal of the oscillation module
It connects；The input terminals of the PFM control modules connects the input terminal of the two-mode field circuit, the PFM control modules it is defeated
Outlet is connected with the control terminal of the oscillation module；The output of the output terminal of the oscillation module and the two-mode field circuit
End connection, for generating and exporting oscillating voltage.
As the improvement of said program, Square root module is further included, the input terminal of the PFM control modules passes through described put down
Root module connects the input terminal of the two-mode field circuit；The input terminal of the Square root module connects the double mode control
The input terminal of circuit processed, the output terminal of the Square root module connect the input terminal of the PFM control modules, for output and institute
State the linear square root electric current of the square root of the input terminal voltage of two-mode field circuit.
As the improvement of said program, the mode selection module include first comparator, the first comparator it is same
For connecting reference voltage, the end of oppisite phase of the first comparator connects the input terminal of the mode selection module, described at phase end
The output terminal of first comparator connects the output terminal of the mode selection module.
As the improvement of said program, PWM control modules include the first phase inverter, the first NMOS tube, the first PMOS tube, the
Two PMOS tube and current source；The input terminal of first phase inverter connects the control terminal of the PWM control modules, and described first is anti-
The output terminal of phase device connects the grid of first NMOS tube；The source electrode of first NMOS tube connects first PMOS tube
Drain electrode, the drain electrode of first NMOS tube connect the output terminal of the PWM control modules；The grid connection of first PMOS tube
The current input terminal of the current source, the source electrode connection feeder ear of first PMOS tube；The grid of second PMOS tube and
Drain electrode is all connected with the current input terminal of the current source, the source electrode connection feeder ear of second PMOS tube；The current source
Current output terminal is connected with ground terminal.
As the improvement of said program, the PFM control modules include the second PMOS tube, the second NMOS tube, the 3rd NMOS
Pipe, the 3rd PMOS tube and current source；The grid of second PMOS tube and drain electrode are all connected with the current input terminal of the current source,
The source electrode connection feeder ear of second PMOS tube；The grid of second NMOS tube connects the control of the PFM control modules
End, the source electrode of second NMOS tube connect the input terminal of the PFM control modules, the drain electrode connection institute of second NMOS tube
State the output terminal of PFM control modules；The grid of grid connection second NMOS tube of 3rd NMOS tube, the described 3rd
The source electrode of NMOS tube connects the drain electrode of the 3rd PMOS tube, and the drain electrode of the 3rd NMOS tube connects the PFM control modules
Output terminal；The grid of 3rd PMOS tube connects the current input terminal of the current source, the source electrode of the 3rd PMOS tube
Connect feeder ear；The current output terminal of the current source is connected with ground terminal.
As the improvement of said program, the oscillation module includes first resistor, second resistance, 3rd resistor, the first biography
Defeated door, the second transmission gate, the second comparator, the second phase inverter, the 4th NMOS tube and capacitance；The first resistor, described second
Resistance and the 3rd resistor are sequentially connected in series between ground terminal and feeder ear；The input terminal of first transmission gate is connected to institute
It states between second resistance and the 3rd resistor, the output terminal of first transmission gate connects the same phase of second comparator
End, the input terminal of second transmission gate are connected between the first resistor and the second resistance, second transmission gate
Output terminal connect the end of oppisite phase of second comparator, the positive control end of first transmission gate and second transmission gate
Output terminal of the negative control end with second comparator is connected, the revertive control end of first transmission gate and second transmission
Output terminal of the revertive control end of door with second phase inverter is connected；The output terminal of second comparator is connected to described shake
Swing the output terminal of module and the input terminal of second phase inverter；The output terminal of second phase inverter is connected to the described 4th
The grid of NMOS tube；The source electrode of 4th NMOS tube connects the control terminal of the oscillation module, the leakage of the 4th NMOS tube
Pole is connected with ground terminal；One end of the capacitance connects the control terminal of the oscillation module, and the other end is connected with ground terminal.
As the improvement of said program, the Square root module includes the first amplifier, the second amplifier, the 4th PMOS
Pipe, the 5th PMOS tube, the 6th PMOS tube, the 7th PMOS tube, the 8th PMOS tube, the 5th NMOS tube, the 6th NMOS tube, the 7th NMOS
Pipe, the 4th resistance and the 5th resistance；The in-phase end of first amplifier connects the input terminal of the Square root module, and described the
The end of oppisite phase of one amplifier is connected by the 4th resistance with ground terminal, the output terminal of first amplifier connection described the
The grid of five NMOS tubes, the source electrode of the 5th NMOS tube connect the drain electrode of the 4th PMOS tube, the 5th NMOS tube
Drain electrode is connected by the 4th resistance with ground terminal；The source electrode connection feeder ear of 4th PMOS tube, the 4th PMOS
The grid of pipe is connected with the drain electrode of the 4th PMOS tube and the grid of the 5th PMOS tube；The source electrode connection of 5th PMOS tube
Feeder ear, the drain electrode of the 5th PMOS tube connect the source electrode of the 6th NMOS tube and the grid of the 6th NMOS tube；Institute
The grid for stating the 6th NMOS tube connects the in-phase end of second amplifier, the drain electrode connection the described 7th of the 6th NMOS tube
The source electrode of NMOS tube；The grid of 7th NMOS tube connects the end of oppisite phase of second amplifier and second amplifier
Output terminal, the drain electrode of the 7th NMOS tube are connected with ground terminal；The drain electrode of 6th PMOS tube is all connected to institute with grid
State the output terminal of the second amplifier, the source electrode connection feeder ear of the 6th PMOS tube；The drain electrode of 6th PMOS tube also connects
The source electrode of the 7th PMOS tube is connected to, the grid of the 7th PMOS tube and drain electrode pass through the 5th resistance and ground terminal
Connection；The grid of 8th PMOS tube is connected with the grid of the 6th PMOS tube, the source electrode connection of the 8th PMOS tube
Feeder ear, the drain electrode of the 8th PMOS tube connect the output terminal of the Square root module.
As the improvement of said program, the first comparator is hysteresis comparator.
As the improvement of said program, the oscillation module further includes the 8th NMOS tube, the 9th NMOS tube and the tenth NMOS
Pipe；The grid of 8th NMOS tube is connected to the current output terminal of the current source, the source electrode connection of the 8th NMOS tube
To the control terminal of the oscillation module, the drain electrode of the 8th NMOS tube is connected with the source electrode of the 4th NMOS tube；Described
The source electrode of four NMOS tubes is connected by the 8th NMOS tube with the control terminal of the oscillation module；The source of 9th NMOS tube
Pole and grid are connected to the current output terminal of the current source, the source of drain electrode the tenth NMOS tube of connection of the 9th NMOS tube
Pole；The grid of tenth NMOS tube connects the grid of the 4th NMOS tube, the drain electrode of the tenth NMOS tube and ground terminal
Connection；The current output terminal of the current source is connected by the 9th NMOS tube and the tenth NMOS tube with ground terminal.
As the improvement of said program, the 4th PMOS tube is consistent with the breadth length ratio of the 5th PMOS tube.
Compared with prior art, the two-mode field circuit of a kind of PWM/PFM provided by the utility model, is selected by pattern
Voltage value size of the module according to the input terminal of the two-mode field circuit is selected, starts PWM control modules under case of heavy load,
Start PFM control modules in underloading, and corresponding control is generated by the PWM control modules or the PFM control modules
Signal processed controls the oscillation mode of oscillating circuit, and corresponding PWM waveform is obtained in the output terminal of the two-mode field circuit
The voltage of voltage or PFM waveforms.Due to the PWM control modules and the oscillation module composition PWM mode occur circuit with
And the PFM control modules and the PFM patterns of oscillation module composition occur circuit and are integrated in an oscillator control unit
In, and reduced the function module of circuit to selecting operating mode by the mode selection module, reduce the static work(of circuit
Consumption, and worked in underloading using PFM patterns, since load current change system switching frequency range is compacter,
So that circuit is more stablized under transient state switching and Static disturbance, the work efficiency under full-load current is improved.
Description of the drawings
Fig. 1 is a kind of circuit diagram of the two-mode field circuit of PWM/PFM in the utility model embodiment.
Fig. 2 is the circuit diagram of Square root module in the utility model embodiment.
Specific embodiment
The following is a combination of the drawings in the embodiments of the present utility model, and the technical scheme in the embodiment of the utility model is carried out
It clearly and completely describes, it is clear that the described embodiments are only a part of the embodiments of the utility model rather than whole
Embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are without creative efforts
All other embodiments obtained shall fall within the protection scope of the present invention.
Referring to Fig. 1, a kind of two-mode field circuit for PWM/PFM that the utility model embodiment provides includes model selection
Module, PWM control modules, PFM control modules and oscillation module.Preferably, the mode selection module includes first comparator
COM1；The PWM control modules include the first phase inverter INV1, the first NMOS tube N1, the first PMOS tube P1, the second PMOS tube P2
With current source I1；The PFM control modules include the second PMOS tube P2, the second NMOS tube N2, the 3rd NMOS tube N3, the 3rd
The PMOS tube P3 and current source I1；The oscillation module includes first resistor R1, second resistance R2,3rd resistor R3, first
Transmission gate T1, the second transmission gate T2, the second comparator COM2, the second phase inverter INV2, the 4th NMOS tube N4 and capacitance C.
With reference to Fig. 1, to a kind of circuit structure of the two-mode field circuit of PWM/PFM of the utility model embodiment offer
It is described in detail.
The control terminal of the mode selection module connects the input terminal Vin of the two-mode field circuit, the pattern choosing
The output terminal for selecting module connects the control terminal of the PWM control modules and the control terminal of the PFM control modules simultaneously.
Specifically, the in-phase end of the first comparator COM1 is used to connect reference voltage Vr, the first comparator
The end of oppisite phase of COM1 connects the input terminal of the mode selection module, is attached to the input terminal of the two-mode field circuit
The output terminal of Vin, the first comparator COM1 connect the output terminal of the mode selection module.Preferably, it is described with reference to electricity
The voltage value of pressure Vr is the constant value between the maximum and minimum value of the voltage value of the input terminal Vin.When described defeated
When entering to hold the voltage value of Vin to be less than the voltage value of the reference voltage Vr, the first comparator COM1 exports high level, i.e. institute
State mode selection module output high level；When the voltage value of the input terminal Vin is more than the voltage value of the reference voltage Vr,
The first comparator COM1 exports low level, i.e., described mode selection module output low level.Preferably, described first compares
Device COM1 is hysteresis comparator, to avoid when the voltage value of the input terminal Vin is near the voltage value of the reference voltage Vr
Shi Fasheng false trippings become, and improve the stability of the two-mode field circuit.
The control terminal of the PWM control modules connects the output terminal of the mode selection module, the PWM control modules
Output terminal connects the input terminal of the oscillating circuit.
Specifically, the control terminal of the input terminal connection PWM control modules of the first phase inverter INV1, described first
The output terminal of phase inverter INV1 connects the grid of the first NMOS tube N1.The source electrode connection described the of the first NMOS tube N1
The drain electrode of one PMOS tube P1, the drain electrode of the first NMOS tube N1 connect the output terminal of the PWM control modules.Described first
The grid of PMOS tube P1 connects the current input terminal of the current source I1, the source electrode connection feeder ear of the first PMOS tube P1
VCC.The grid of the second PMOS tube P2 and drain electrode are all connected with the current input terminal of the current source I1, second PMOS tube
The source electrode connection feeder ear VCC of P2.The current output terminal of the current source I1 is connected with ground terminal GND.First PMOS tube
The grid of P1 is connected with the grid of the second PMOS tube P2, and the source electrode of the first PMOS tube P1 and the 2nd PMOS
The source electrode connection of pipe P2, the first PMOS tube P1 and the second PMOS tube P2 form current-mirror structure.
The control terminal of the PFM control modules connects the output terminal of the mode selection module, the PFM control modules
Input terminal connects the input terminal Vin of the two-mode field circuit, output terminal and the oscillation module of the PFM control modules
Control terminal connection.
Specifically, the grid of the second PMOS tube P2 and drain electrode are all connected with the current input terminal of the current source I1, institute
State the source electrode connection feeder ear VCC of the second PMOS tube P2.The grid of the second NMOS tube N2 connects the PFM control modules
Control terminal, the source electrode of the second NMOS tube N2 connect the input terminal of the PFM control modules, the leakage of the second NMOS tube N2
Pole connects the output terminal of the PFM control modules.The grid of the 3rd NMOS tube N3 connects the grid of the second NMOS tube N2
Pole, the source electrode of the 3rd NMOS tube N3 connect the drain electrode of the 3rd PMOS tube P3, and the drain electrode of the 3rd NMOS tube N3 connects
Connect the output terminal of the PFM control modules.The grid of the 3rd PMOS tube P3 connects the current input terminal of the current source I1,
The source electrode connection feeder ear VCC of the 3rd PMOS tube P3.The current output terminal of the current source I1 is connected with ground terminal GND.
The grid of the 3rd PMOS tube P3 is connected with the grid of the second PMOS tube P2, and the source electrode of the 3rd PMOS tube P3
It is connected with the source electrode of the second PMOS tube P2, the 3rd PMOS tube P3 and the second PMOS tube P2 form current mirror knot
Structure.
The control terminal of the oscillation module simultaneously with the output terminal of the PWM control modules and the output of the PFM modules
End connection, the output terminal of the oscillation module are connected with the output end vo ut of the two-mode field circuit.
Specifically, the first resistor R1, the second resistance R2 and the 3rd resistor R3 are sequentially connected in series in ground terminal
Between GND and feeder ear VCC.The input terminal of the first transmission gate T1 is connected to the second resistance R2 and the 3rd resistor
Between R3, the output terminal of the first transmission gate T1 connects the in-phase end of the second comparator COM2, second transmission gate
The input terminal of T2 is connected between the first resistor R1 and the second resistance R2, and the output terminal of the second transmission gate T2 connects
Connect the end of oppisite phase of the second comparator COM2, the positive control end of the first transmission gate T1 and the second transmission gate T2's is negative
Output terminal of the control terminal with the second comparator COM2 is connected, the revertive control end and described second of the first transmission gate T1
Output terminal of the revertive control end of transmission gate T2 with the second phase inverter INV2 is connected.The output of the second comparator COM2
End is connected to the output terminal of the oscillation module and the input terminal of the second phase inverter INV2.The second phase inverter INV2's
Output terminal is connected to the grid of the 4th NMOS tube N4.One end of the capacitance C connects the control terminal of the oscillation module, separately
One end is connected with ground terminal GND.The control terminal of the source electrode connection oscillation module of the 4th NMOS tube N4, the described 4th
The drain electrode of NMOS tube is connected with ground terminal, forms the discharge loop of the capacitance C by the output voltage control of the oscillation module.
Preferably, the oscillation module further includes the 8th NMOS tube N8, the 9th NMOS tube N9 and the tenth NMOS tube N10.Institute
It states the source electrode of the 9th NMOS tube N9 and grid is connected to the current output terminal of the current source I1, the leakage of the 9th NMOS tube N9
Pole connects the source electrode of the tenth NMOS tube N10；The grid of the tenth NMOS tube N10 connects the grid of the 4th NMOS tube N4,
The drain electrode of the tenth NMOS tube N10 is connected with ground terminal GND；The current output terminal of the current source I1 passes through the described 9th
NMOS tube N9 and the tenth NMOS tube N10 are connected with ground terminal GND.
Preferably, the two-mode field circuit further includes Square root module, the input terminal connection of the Square root module
The input terminal Vin of the two-mode field circuit, the output terminal I2 connections PFM control modules of the Square root module it is defeated
Enter end, i.e., the input terminal of described PFM control modules passes through the Square root module and the input terminal of the two-mode field circuit
Vin connections.
Specifically, referring to Fig. 2, the Square root module includes the first amplifier COM3, the second amplifier COM4, the 4th
PMOS tube P4, the 5th PMOS tube P5, the 6th PMOS tube P6, the 7th PMOS tube P7, the 8th PMOS tube P8, the 5th NMOS tube N5,
Six NMOS tube N6, the 7th NMOS tube N7, the 4th resistance R4 and the 5th resistance R5.
The in-phase end of the first amplifier COM3 connects the input terminal of the Square root module, first amplifier
The end of oppisite phase of COM3 is connected by the 4th resistance R4 with ground terminal GND, the output terminal connection of the first amplifier COM3
The grid of the 5th NMOS tube N5, the source electrode of the 5th NMOS tube N5 connects the drain electrode of the 4th PMOS tube P4, described
The drain electrode of 5th NMOS tube N5 is connected by the 4th resistance R4 with ground terminal GND.The source electrode of the 4th PMOS tube P4 connects
Connect the grid of feeder ear VCC, the 4th PMOS tube P4 and the drain electrode of the 4th PMOS tube P4 and the grid of the 5th PMOS tube P5
Pole connects.The drain electrode connection the described 6th of source electrode connection the feeder ear VCC, the 5th PMOS tube P5 of the 5th PMOS tube P5
The grid of the source electrode of NMOS tube N6 and the 6th NMOS tube N6.Grid connection second amplification of the 6th NMOS tube N6
The in-phase end of device COM4, the drain electrode of the 6th NMOS tube N6 connect the source electrode of the 7th NMOS tube N7.7th NMOS
The end of oppisite phase of grid connection the second amplifier COM4 of pipe N7 and the output terminal of the second amplifier COM4, the described 7th
The drain electrode of NMOS tube N7 is connected with ground terminal GND.The drain electrode of the 6th PMOS tube P6 is all connected to described second with grid and puts
The output terminal of big device COM4, the source electrode connection feeder ear of the 6th PMOS tube P6.The drain electrode of the 6th PMOS tube P6 also connects
Be connected to the source electrode of the 7th PMOS tube P7, the grid of the 7th PMOS tube P7 and drain electrode by the 5th resistance R5 with
Ground terminal GND connections.The grid of the 8th PMOS tube P8 is connected with the grid of the 6th PMOS tube P6, the 8th PMOS
The drain electrode of source electrode connection the feeder ear VCC, the 8th PMOS tube P8 of pipe P8 connect the output terminal I2 of the Square root module.
And the 5th PMOS tube P5 and the 4th PMOS tube P4 composition current-mirror structures, the 6th PMOS tube P6
Current-mirror structure is formed with the 8th PMOS tube P8.
The input terminal Vin input voltages of the two-mode field circuit input electricity from the input terminal of the Square root module
The negative-feedback circuit of pressure, the first amplifier COM3, the 5th NMOS tube N5 and the 4th resistance R4 compositions makes described
The in-phase end of first amplifier COM3 is equal with reverse phase terminal voltage value, it is preferable that in the 4th PMOS tube P4 and the described 5th
When the breadth length ratio of PMOS tube P5 is consistent, flows through the electric current of the 5th PMOS tube P5 and flow through the electric current of the 4th PMOS tube P4
It is equal, if flowing through the current value I3 of the 5th PMOS tube P5, have：
Due to the second amplifier COM4, the 5th PMOS tube P5, the 7th PMOS tube P7, the 6th NMOS
Pipe N6, the 7th NMOS tube N7 and the 5th resistance R5 composition unit gain negative feedback loops, the 7th NMOS tube N7
Gate voltage values it is equal with the source voltage values of the 7th PMOS tube P7, the 7th NMOS tube N7 is made to be operated in saturation
Area, the 7th PMOS tube P7 are operated in sub-threshold region, and the threshold voltage value of the 7th NMOS tube N7 is approximately equal to the described 7th
The gate source voltage value of PMOS tube P7, if the threshold voltage value is V0 so that the threshold voltage of the 7th NMOS tube N7 and institute
The threshold voltage for stating the 7th PMOS tube P7 is equal in magnitude.I.e.：
VTHN7=VTHP7≈VGSP7
Have for the 7th PMOS tube：
Vb=Va-VGSP7=Va-VTHP7
Wherein Va is the voltage value at a in Fig. 2, and Vb is the voltage value at b in Fig. 2.
According to the saturation current calculation formula of metal-oxide-semiconductor, the drain current of the 7th NMOS tube N7 is at this time：
If the breadth length ratio of the 6th PMOS tube P6 and the 7th PMOS tube P7 is 1：M, the then electric current for flowing through the 7th PMOS tube P7 have：
Summary formula can obtain：
Since the resistance value and the resistance value of the 5th resistance R5 of the 4th resistance R4 determine, thus the output current value of output terminal I2 with
The evolution of the voltage value of the input terminal Vin inputs is linear.If：
Have：
It avoids in the linear feelings of the output current value of the output terminal I2 and the voltage value of the input terminal Vin
Under condition, in a wide range of load switching, the switching frequency for be easy to causeing the system of the two-mode field circuit application adjusts width
It spends big so that the system is difficult to control, and improves the controllability of the system.
In the following, with reference to Fig. 1 and Fig. 2, the work to the two-mode field circuit of PWM/PFM provided by the utility model a kind of
Process is described in detail.
First, load voltage inputs the two-mode field circuit by the input terminal Vin.The mode selection module
The voltage value inputted according to the input terminal Vin inputs compared with the voltage value of the reference voltage Vr in the input terminal Vin
Voltage value be less than the reference voltage Vr voltage value when, the two-mode field circuit output high level, in the present embodiment
In circuit, it is that the control PFM control modules start, the two-mode field circuit is made to enter PFM patterns and is worked；
When the voltage value of the input terminal Vin inputs is more than the voltage value of the reference voltage Vr, the two-mode field circuit output
Low level in the present embodiment circuit, is that the control PWM control modules start, enters the two-mode field circuit
PWM mode works.
When the oscillating circuit exports low level, the grid of the second NMOS tube N2 and the 3rd NMOS tube N3's
Grid is low level, and the second NMOS tube N2 and the 3rd NMOS tube N3 are turned off, and the PFM control modules are closed.
Since the first PMOS tube P1 and the second PMOS tube P2 forms current-mirror structure, the first PMOS tube P1 conductings, institute
The second NMOS tube N2 conductings are stated, so the linear pass of electric current of the channel current of the first PMOS tube P1 and the current source I1
System.The PWM control modules start and are exported to the oscillating circuit, and the capacitance C is started to charge up.The PWM control modules
The size of current of output terminal be：
IPWM=k1I1
Wherein k1For the first PMOS tube P1 and the image current ratio of the second PMOS tube P2.
It is described when the both end voltage difference of the capacitance C is more than the in-phase end voltage value of the second comparator COM2
The output terminal output low level of second comparator COM2, i.e., described two-mode field circuit output low level, the discharge loop
Conducting, the capacitance C start to discharge；Until the both end voltage difference of the capacitance C is same less than the second comparator COM2
Phase terminal voltage value, the output terminal output high level of the second comparator COM2, i.e., the described high electricity of two-mode field circuit output
Flat, the discharge loop cut-off, the capacitance C continues to charge.Therefore there is the capacitance C voltage upper limit value V1 and lower limiting value V2：
Therefore in a PWM mode, the two-mode field circuit output end pulse period is：
The output pulse of constant cycle is obtained, i.e., described two-mode field circuit exports PWM waveform arteries and veins in a PWM mode
Punching.
When the oscillating circuit exports high level, the cut-off of the first NMOS tube N1, the PWM control modules are closed
It closes.Second NMOS tube N2's and the 3rd NMOS tube N3 be both turned on, the PFM control modules start.The square root
The output terminal I2 output currents of module pass through the second NMOS tube N2, are exported from the output terminal of the PFM control modules.Due to
The 3rd PMOS tube P3 and the second PMOS tube P2 form current-mirror structure, the 3rd PMOS tube P3 conductings, and described the
Three NMOS tube N3 are turned on, so the drain current of the 3rd PMOS tube P3：
I4=k2I1
Wherein k2For the 3rd PMOS tube P3 and the image current ratio of the second PMOS tube P2
Output terminal I2 of the electric current with the Square root module that the charging current of the capacitance C is the current source I1 at this time
The sum of electric current, when the both end voltage difference of the capacitance C is more than the in-phase end voltage value of the second comparator COM2, institute
The output terminal output low level of the second comparator COM2 is stated, i.e., described two-mode field circuit output low level is described to discharge back
Road turns on, and the capacitance C starts to discharge；Until the both end voltage difference of the capacitance C is less than the second comparator COM2's
In-phase end voltage value, the output terminal output high level of the second comparator COM2, i.e., described two-mode field circuit output are high
Level, the discharge loop cut-off, the capacitance C continue to charge.
Therefore under PFM patterns, the two-mode field circuit output end pulse period is：
Obtain output frequency with the voltage value size variation of input terminal Vin the output pulse changed and the double mode
Control circuit exports PFM waveform pulses under PFM patterns.
A kind of two-mode field circuit for PWM/PFM that the utility model embodiment provides, passes through mode selection module root
According to the voltage value size of the input terminal of the two-mode field circuit, start PWM control modules under case of heavy load, in underloading feelings
Start PFM control modules under condition, and corresponding control signal, control are generated by the PWM control modules or the PFM control modules
The oscillation mode of oscillating circuit processed obtains the voltage or PFM of corresponding PWM waveform in the output terminal of the two-mode field circuit
The voltage of waveform.Since circuit and the PFM occur for the PWM mode of the PWM control modules and oscillation module composition
Control module and the PFM patterns of oscillation module composition occur circuit and are integrated in an oscillator control unit, and by institute
Mode selection module is stated to selecting operating mode, reduces the function module of circuit, reduces the quiescent dissipation of circuit, and
It is worked in the case of underloading using PFM patterns, since load current change system switching frequency range is compacter so that circuit exists
Transient state switches and more stablizes under Static disturbance, improves the work efficiency under full-load current.
The above is the preferred embodiment of the utility model, it is noted that for the ordinary skill of the art
For personnel, on the premise of the utility model principle is not departed from, several improvements and modifications can also be made, these are improved and profit
Decorations are also considered as the scope of protection of the utility model.
Claims (10)
1. the two-mode field circuit of a kind of PWM/PFM, which is characterized in that including mode selection module, PWM control modules, PFM
Control module and oscillation module；
The input terminal of the mode selection module connects the input terminal of the two-mode field circuit, the mode selection module
Output terminal connects the control terminal of the PWM control modules and the control terminal of the PFM control modules simultaneously；
The output terminal of the PWM control modules is connected with the control terminal of the oscillation module；
The input terminals of the PFM control modules connects the input terminal of the two-mode field circuit, the PFM control modules it is defeated
Outlet is connected with the control terminal of the oscillation module；
The output terminal of the oscillation module is connected with the output terminal of the two-mode field circuit, for generating and exporting vibration electricity
Pressure.
2. two-mode field circuit as described in claim 1, which is characterized in that further include Square root module, the PFM controls
The input terminal of module connects the input terminal of the two-mode field circuit by the Square root module；
The input terminal of the Square root module connects the input terminal of the two-mode field circuit, the output of the Square root module
End connects the input terminal of the PFM control modules, for exporting square with the input terminal voltage of the two-mode field circuit
The linear square root electric current of root.
3. two-mode field circuit as described in claim 1, which is characterized in that the mode selection module compares including first
Device, for the in-phase end of the first comparator for connecting reference voltage, the end of oppisite phase of the first comparator connects the pattern
The input terminal of selecting module, the output terminal of the first comparator connect the output terminal of the mode selection module.
4. two-mode field circuit as described in claim 1, which is characterized in that PWM control modules include the first phase inverter, the
One NMOS tube, the first PMOS tube, the second PMOS tube and current source；
The input terminal of first phase inverter connects the control terminal of the PWM control modules, the output terminal of first phase inverter
Connect the grid of first NMOS tube；
The source electrode of first NMOS tube connects the drain electrode of first PMOS tube, described in the drain electrode connection of first NMOS tube
The output terminal of PWM control modules；The current input terminal of the grid connection current source of first PMOS tube, described first
The source electrode connection feeder ear of PMOS tube；The grid of second PMOS tube and drain electrode are all connected with the electric current input of the current source
End, the source electrode connection feeder ear of second PMOS tube；
The current output terminal of the current source is connected with ground terminal.
5. two-mode field circuit as described in claim 1, which is characterized in that the PFM control modules include the 2nd PMOS
Pipe, the second NMOS tube, the 3rd NMOS tube, the 3rd PMOS tube and current source；
The grid of second PMOS tube and drain electrode are all connected with the current input terminal of the current source, the source of second PMOS tube
Pole connects feeder ear；The grid of second NMOS tube connects the control terminal of the PFM control modules, second NMOS tube
Source electrode connects the input terminal of the PFM control modules, and the drain electrode of second NMOS tube connects the output of the PFM control modules
End；The grid of 3rd NMOS tube connects the grid of second NMOS tube, described in the source electrode connection of the 3rd NMOS tube
The drain electrode of 3rd PMOS tube, the drain electrode of the 3rd NMOS tube connect the output terminal of the PFM control modules；3rd PMOS
The grid of pipe connects the current input terminal of the current source, the source electrode connection feeder ear of the 3rd PMOS tube；
The current output terminal of the current source is connected with ground terminal.
6. such as 4 or 5 any one of them two-mode field circuit of claim, which is characterized in that the oscillation module includes the
One resistance, second resistance, 3rd resistor, the first transmission gate, the second transmission gate, the second comparator, the second phase inverter, the 4th NMOS
Pipe and capacitance；
The first resistor, the second resistance and the 3rd resistor are sequentially connected in series between ground terminal and feeder ear；
The input terminal of first transmission gate is connected between the second resistance and the 3rd resistor, first transmission gate
Output terminal connect the in-phase end of second comparator, the input terminal of second transmission gate be connected to the first resistor with
Between the second resistance, the output terminal of second transmission gate connects the end of oppisite phase of second comparator, and described first passes
The output terminal of the positive control end of defeated door and the negative control end of second transmission gate with second comparator is connected, and described
The output terminal of the revertive control end of one transmission gate and the revertive control end of second transmission gate with second phase inverter is connected；
The output terminal of second comparator is connected to the output terminal of the oscillation module and the input terminal of second phase inverter；
The output terminal of second phase inverter is connected to the grid of the 4th NMOS tube；
The source electrode of 4th NMOS tube connects the control terminal of the oscillation module, the drain electrode of the 4th NMOS tube and ground terminal
Connection；
One end of the capacitance connects the control terminal of the oscillation module, and the other end is connected with ground terminal.
7. two-mode field circuit as claimed in claim 2, which is characterized in that the Square root module includes the first amplification
Device, the second amplifier, the 4th PMOS tube, the 5th PMOS tube, the 6th PMOS tube, the 7th PMOS tube, the 8th PMOS tube, the 5th NMOS
Pipe, the 6th NMOS tube, the 7th NMOS tube, the 4th resistance and the 5th resistance；
The in-phase end of first amplifier connects the input terminal of the Square root module, and the end of oppisite phase of first amplifier leads to
It crosses the 4th resistance to be connected with ground terminal, the output terminal of first amplifier connects the grid of the 5th NMOS tube, institute
The source electrode for stating the 5th NMOS tube connects the drain electrode of the 4th PMOS tube, and the drain electrode of the 5th NMOS tube passes through the described 4th electricity
Resistance is connected with ground terminal；
The source electrode connection feeder ear of 4th PMOS tube, the grid of the 4th PMOS tube and the drain electrode of the 4th PMOS tube
And the 5th PMOS tube grid connection；The source electrode connection feeder ear of 5th PMOS tube, the drain electrode of the 5th PMOS tube connect
Connect the source electrode of the 6th NMOS tube and the grid of the 6th NMOS tube；The grid connection described second of 6th NMOS tube
The in-phase end of amplifier, the drain electrode of the 6th NMOS tube connect the source electrode of the 7th NMOS tube；7th NMOS tube
Grid connects the end of oppisite phase of second amplifier and the output terminal of second amplifier, the drain electrode of the 7th NMOS tube with
Ground terminal connects；
The drain electrode of 6th PMOS tube is all connected to the output terminal of second amplifier with grid, the 6th PMOS tube
Source electrode connects feeder ear；The drain electrode of 6th PMOS tube is also connected to the source electrode of the 7th PMOS tube, the 7th PMOS
The grid of pipe and drain electrode are connected by the 5th resistance with ground terminal；The grid and the described 6th of 8th PMOS tube
The grid of PMOS tube connects, the source electrode connection feeder ear of the 8th PMOS tube, described in the drain electrode connection of the 8th PMOS tube
The output terminal of Square root module.
8. two-mode field circuit as claimed in claim 3, which is characterized in that the first comparator is hysteresis comparator.
9. two-mode field circuit as claimed in claim 6, which is characterized in that the oscillation module further includes the 8th NMOS
Pipe, the 9th NMOS tube and the tenth NMOS tube；
The grid of 8th NMOS tube is connected to the current output terminal of the current source, the source electrode connection of the 8th NMOS tube
To the control terminal of the oscillation module, the drain electrode of the 8th NMOS tube is connected with the source electrode of the 4th NMOS tube；Described
The source electrode of four NMOS tubes is connected by the 8th NMOS tube with the control terminal of the oscillation module；
The source electrode and grid of 9th NMOS tube are connected to the current output terminal of the current source, the leakage of the 9th NMOS tube
Pole connects the source electrode of the tenth NMOS tube；The grid of grid connection the 4th NMOS tube of tenth NMOS tube, the described tenth
The drain electrode of NMOS tube is connected with ground terminal；The current output terminal of the current source passes through the 9th NMOS tube and the described tenth
NMOS tube is connected with ground terminal.
10. the breadth length ratio of two-mode field circuit as claimed in claim 7, the 4th PMOS tube and the 5th PMOS tube
Unanimously.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721355602.4U CN207460000U (en) | 2017-10-19 | 2017-10-19 | A kind of two-mode field circuit of PWM/PFM |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721355602.4U CN207460000U (en) | 2017-10-19 | 2017-10-19 | A kind of two-mode field circuit of PWM/PFM |
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| CN207460000U true CN207460000U (en) | 2018-06-05 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107546982A (en) * | 2017-10-19 | 2018-01-05 | 广州大学 | A kind of two-mode field circuit of PWM/PFM |
| CN115811241A (en) * | 2023-02-08 | 2023-03-17 | 四川大学 | Single-stage bridgeless staggered parallel Boost-LLC AC-DC converter hybrid control method |
-
2017
- 2017-10-19 CN CN201721355602.4U patent/CN207460000U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107546982A (en) * | 2017-10-19 | 2018-01-05 | 广州大学 | A kind of two-mode field circuit of PWM/PFM |
| CN107546982B (en) * | 2017-10-19 | 2024-01-16 | 广州大学 | PWM/PFM dual-mode control circuit |
| CN115811241A (en) * | 2023-02-08 | 2023-03-17 | 四川大学 | Single-stage bridgeless staggered parallel Boost-LLC AC-DC converter hybrid control method |
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