CN207234647U - Voltage comparator, control chip and Switching Power Supply - Google Patents
Voltage comparator, control chip and Switching Power Supply Download PDFInfo
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- CN207234647U CN207234647U CN201721094325.6U CN201721094325U CN207234647U CN 207234647 U CN207234647 U CN 207234647U CN 201721094325 U CN201721094325 U CN 201721094325U CN 207234647 U CN207234647 U CN 207234647U
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Abstract
The utility model is suitable for electronic technology field, a kind of voltage comparator, control chip and Switching Power Supply provided by the utility model, and the voltage comparator includes：Input circuit, Current Voltage conversion circuit, voltage clamping circuit and output circuit, by setting voltage clamping circuit in a comparator, when sampled voltage is less than reference voltage, voltage clamping circuit controls the section point voltage of the output terminal of first order input circuit in the first preset voltage value, and the first preset voltage value is less than the supply voltage；When sampled voltage is more than reference voltage, the first node voltage of Current Voltage conversion circuit output terminal is begun to ramp up by zero, voltage clamping circuit controls the rising peak of first node voltage in the second preset voltage value, second preset voltage value is less than the supply voltage, since first node voltage and section point voltage need not rise to supply voltage, shorten the response time of voltage comparator.
Description
Technical field
The utility model belongs to electronic technology field, more particularly to a kind of voltage comparator, control chip and Switching Power Supply.
Background technology
, it is necessary to control control chip output control signal by comparator in the control chip of AC-DC Switching Power Supplies,
Work(in AC-DC systems is caused in the presence of the longer response time from input signal is received to output control signal due to comparator
Rate pipe in turn off process there are larger delay, further cause the error of inductive current peak in AC-DC Switching Power Supplies compared with
Greatly, finally cause load capacity of the output terminal of AC-DC Switching Power Supplies under different input line voltages to change greatly, cause height
During input line voltage, the inductive current of AC-DC Switching Power Supplies easily enters saturation state, reduces the safety of AC-DC Switching Power Supplies
Property.
Utility model content
In view of this, the utility model embodiment provides a kind of voltage comparator, control chip and Switching Power Supply, can
Quick response and output control signal, can effectively reduce from the response time for receiving input signal to output control signal.
The first aspect of the utility model embodiment, there is provided a kind of voltage comparator, including：Input circuit, electric current electricity
Press conversion circuit, voltage clamping circuit and output circuit；The power end of the input circuit, the Current Voltage conversion circuit
The power end of power end and the output circuit accesses same supply voltage, the ground terminal of the Current Voltage conversion circuit and
The ground terminal of the output circuit is grounded；The first input end access sampled voltage of the input circuit, the of input circuit
Two input terminals access reference voltage；First output terminal of the input circuit and the first input of the Current Voltage conversion circuit
End connection, the second output terminal of the input circuit are connected with the second input terminal of the Current Voltage conversion circuit；It is described defeated
Going out circuit includes first order output circuit and second level output circuit, and the power end of the first order output circuit and the second level are defeated
The power end for going out circuit accesses the supply voltage, and the ground terminal of the first order output circuit and second level output circuit is equal
Ground connection, the output terminal of the first order output circuit are connected with the input terminal of the second level output circuit, and the second level is defeated
Go out the output terminal output control voltage of circuit；The output terminal of the Current Voltage conversion circuit exports electricity with the first order respectively
The input terminal on road is connected with the first control terminal of the voltage clamping circuit, the second control terminal of the voltage clamping circuit and
Output terminal of three control terminals respectively with the first order output circuit is connected.
Further, the voltage clamping circuit includes：First NMOS tube and the second NMOS tube；
The grid difference of the source electrode of first NMOS tube, the drain electrode of second NMOS tube and the 2nd NMOS pipes
It is connected with the output terminal of the Current Voltage conversion circuit, the draining of first NMOS tube, the grid of first NMOS tube
The output terminal that the first order output circuit is distinguished with the source electrode of second NMOS tube connects.
Further, the input circuit includes：First PMOS tube, the second PMOS tube and the 3rd PMOS pipes；Described first
The source electrode of PMOS tube accesses the supply voltage, the drain electrode of first PMOS tube respectively with the source electrode of second PMOS tube and
The source electrode connection of 3rd PMOS tube, the grid access first control signal of the first PMOS pipes, the grid of second PMOS tube
The sampled voltage is accessed in pole, and the grid of the 3rd PMOS tube accesses the reference voltage, the drain electrode of second PMOS tube
It is connected with the first input end of the Current Voltage conversion circuit, drain electrode and the Current Voltage of the 3rd PMOS tube convert
The second input terminal connection of circuit.
Further, the Current Voltage conversion circuit includes：4th PMOS tube, the 5th PMOS tube, the 6th PMOS tube,
Seven PMOS tube, the 3rd NMOS tube, the 4th NMOS tube, the 5th NMOS pipes and the 6th NMOS tube；The source electrode of 4th PMOS tube
Access the supply voltage with the source electrode of the 5th PMOS tube, the drain and gate of the 4th PMOS tube respectively with it is described
The grid connection of 5th PMOS pipes, the drain and gate of the 4th PMOS tube connect with the source electrode of the 6th PMOS tube respectively
Connect, the drain electrode of the 5th PMOS tube is connected with the source electrode of the 7th PMOS tube, the drain and gate of the 6th PMOS tube
The grid connection of 7th PMOS tube respectively；The drain electrode drain electrode with the 6th PMOS tube respectively of the 3rd NMOS pipes
With the connection of grid, the drain electrode of the 4th NMOS tube is connected with the drain electrode of the 7th PMOS tube；3rd NMOS tube
Source electrode is connected with the drain electrode of the 5th NMOS tube, and the source electrode of the 4th NMOS tube is connected with the drain electrode of the 6th NMOS tube, institute
State the grid of the 3rd NMOS tube and the grid of the 4th NMOS tube accesses second control signal；The source electrode of 5th NMOS tube and
The source electrode of 6th NMOS tube is grounded respectively, and the grid of the 5th NMOS pipes and the grid of the 6th NMOS tube access the 3rd control
Signal processed；The source electrode of 3rd NMOS tube and the common contact of the drain electrode of the 5th NMOS tube are Current Voltage conversion electricity
The common contact of the first input end on road, the source electrode of the 4th NMOS tube and the drain electrode of the 6th NMOS tube is electric current electricity
The second input terminal of conversion circuit is pressed, the common contact of the drain electrode and the drain electrode of the 7th PMOS pipes of the 4th NMOS tube is
The output terminal of the Current Voltage conversion circuit.
Further, the first order output circuit includes the 8th PMOS tube and the 7th NMOS tube, the second level output
Circuit includes the 9th PMOS tube and the 8th NMOS tube；The source electrode of 8th PMOS tube and the source electrode of the 9th PMOS tube connect
Enter the supply voltage, the drain electrode of the 8th PMOS tube is connected with the drain electrode of the 7th NMOS tube, the 9th PMOS tube
Drain electrode be connected with the drain electrode of the 8th NMOS tube, the grid of the 8th PMOS tube and the grid of the 9th PMOS tube
Access the 4th control signal；The source electrode of 7th NMOS tube and the source grounding of the 8th NMOS tube；Described 7th
The grid of NMOS tube is the input terminal of the first order output circuit, the drain electrode of the 8th PMOS tube and the 7th NMOS
Contact is the output terminal of the first order output circuit altogether for the drain electrode of pipe, and the grid of the 8th NMOS tube is that the second level is defeated
Go out the input terminal of circuit, the common contact of drain electrode with the drain electrode of the 8th NMOS tube of the 9th PMOS tube is described second
The output terminal of level output circuit.
Further, the first order output circuit further includes：First phase inverter and the second phase inverter, described first is anti-phase
Device and second inverter series, the input terminal of first phase inverter access the drain electrode of the 9th PMOS tube with it is described
The common contact of the drain electrode of 8th NMOS tube.
The second aspect of the utility model embodiment, there is provided a kind of control chip, including：Compare including above-mentioned voltage
Device, further includes：With door, nor gate, PWM module, drive circuit, sampling resistor and power tube；
The output terminal of the voltage comparator is connected with described with the first input end of door, described and the second input terminal of door
LEB shielded signals are accessed, it is described to be connected with the output terminal of door with the first input end of the PWM module；The of the nor gate
One input terminal access OSC clock signals, the nor gate first input end ground connection, the output terminal of the nor gate with it is described
The second input terminal connection of PWM module；The output terminal of the PWM modules is connected with the input terminal of the drive circuit, the drive
The output terminal of dynamic circuit is connected with the grid of the power tube, the drain electrode access input voltage of the power tube, the power tube
Source electrode be connected with one end of the sampling resistor, the other end of sampling resistor ground connection, the source electrode of the power tube and institute
The common contact for stating sampling resistor is connected with the first input end of the voltage comparator.
Further, the power tube is NMOS tube.
The third aspect of the utility model embodiment, there is provided a kind of Switching Power Supply, including above-mentioned control chip, are also wrapped
Include：Input capacitance, chip power supply capacitance, energy storage inductor, fly-wheel diode, output feedback diode, output capacitance and load electricity
Resistance；
The drain electrode of the power tube of the control chip is the first input end of the control chip, and the control chip also wraps
The second input terminal is included, for accessing the power supply of chip power supply in order to control, the ground terminal of the sampling resistor of the control chip is institute
State the ground terminal of control chip；
One end access supply voltage of the input capacitance, the other end ground connection of the input capacitance；The control chip
First input end accesses input voltage, and the second input terminal of the control chip and the cathode of the output feedback diode connect
Connect, the ground terminal of the control chip is connected with one end of the energy storage inductor, the other end of the energy storage inductor with it is described defeated
Go out the anode connection of feedback diode；
The chip power supply capacitance is connected on the second input terminal of the control chip and the output feedback diode cathode
Common contact and the ground terminal of the control chip and the common contact of the energy storage inductor between；The cathode of the fly-wheel diode
Access the common contact of the chip power supply capacitance and energy storage inductor, the plus earth of the fly-wheel diode；The output capacitance
The common contact of the energy storage inductor and output feedback diode, the output capacitance are accessed in one end in parallel with the load resistance
The other end ground connection in parallel with the load resistance, the both ends of the load resistance are the output terminal of the Switching Power Supply.
Further, the supply voltage is alternating voltage, and the output terminal of the Switching Power Supply is to export direct current just
Cathode output end.
The beneficial effect of the utility model embodiment compared with prior art is：One kind that the utility model embodiment provides
Voltage comparator, control chip and Switching Power Supply, by setting voltage clamping circuit in a comparator, are less than ginseng in sampled voltage
When examining voltage, voltage clamping circuit controls the section point voltage of the output terminal of first order input circuit in the first predeterminated voltage
Value, and the first preset voltage value is less than the supply voltage；When sampled voltage is more than reference voltage, Current Voltage conversion circuit
The first node voltage of output terminal is begun to ramp up by zero, and voltage clamping circuit is by the control of the rising peak of first node voltage the
Two preset voltage values, the second preset voltage value are less than the supply voltage, due to first node voltage and section point voltage all
Without rising to supply voltage, shorten the response time of voltage comparator.
Brief description of the drawings
, below will be to embodiment or the prior art in order to illustrate more clearly of the technical scheme in the embodiment of the utility model
Attached drawing is briefly described needed in description, it should be apparent that, drawings in the following description are only that this practicality is new
Some embodiments of type, for those of ordinary skill in the art, without having to pay creative labor, can be with
Other attached drawings are obtained according to these attached drawings.
Fig. 1 is a kind of modular structure schematic diagram for voltage comparator that the utility model embodiment provides；
Fig. 2 is a kind of electrical block diagram for voltage comparator that the utility model embodiment provides；
Fig. 3 is a kind of electrical block diagram for control chip that the utility model embodiment provides；
Fig. 4 is a kind of electrical block diagram for Switching Power Supply that the utility model embodiment provides；
Fig. 5 is the oscillogram of the AC-DC switch power supply, inductance and currents for the perfect condition that the utility model embodiment provides；
Fig. 6 is the oscillogram of the AC-DC switch power supply, inductance and currents for the virtual condition that the utility model embodiment provides；
Fig. 7 is the ripple of the inductive current of the Switching Power Supply under the high and low input line voltage that the utility model embodiment provides
Shape figure；
The correspondence schematic diagram of the different input voltages that Fig. 8 the utility model embodiments provide and overload protection point.
Embodiment
In being described below, in order to illustrate rather than in order to limit, it is proposed that such as tool of particular system structure, technology etc
Body details, to understand thoroughly the utility model embodiment.However, it will be clear to one skilled in the art that there is no these
The utility model can also be realized in the other embodiments of detail.In other situations, omit to well-known system,
The detailed description of device, circuit and method, in case unnecessary details hinders the description of the utility model.
It should be appreciated that ought use in this specification and in the appended claims, term " comprising " and "comprising" instruction
Described feature, entirety, step, operation, the presence of element and/or component, but it is not precluded from one or more of the other feature, whole
Body, step, operation, element, component and/or its presence or addition for gathering.
It is also understood that in this utility model term used in the description merely for the sake of description specific embodiment
Purpose and be not intended to limit the utility model.As used in the utility model specification and appended book
Like that, unless context clearly indicates other situations, otherwise " one " of singulative, "one" and "the" are intended to include plural number
Form.
It will be further appreciated that used in the utility model specification and appended book term " and/
Or " refer to any combinations and all possible combinations of one or more of the associated item listed, and including these groups
Close.
As used in this specification and in the appended claims, term " if " can be according to context quilt
Be construed to " when ... " or " once " or " in response to determining " or " in response to detecting ".Similarly, phrase " if it is determined that " or
" if detecting [described condition or event] " can be interpreted to mean according to context " once it is determined that " or " in response to true
It is fixed " or " once detecting [described condition or event] " or " in response to detecting [described condition or event] ".
In order to illustrate technical solution described in the utility model, illustrated below by specific embodiment.
With reference to figure 1, Fig. 1 is a kind of modular structure schematic diagram for voltage comparator that the utility model embodiment provides.For
Easy to explanation, to illustrate only include with the relevant part of the utility model, the voltage comparator 100 of the present embodiment：Input electricity
Road 10, Current Voltage conversion circuit 20, voltage clamping circuit 30 and output circuit 40.
The power end of the power end of input circuit 10, the power end of Current Voltage conversion circuit 20 and output circuit 40 connects
Enter supply voltage VDD.The ground terminal of Current Voltage conversion circuit 20 and the ground terminal of output circuit 40 are grounded GND.Input electricity
The first input end 101 on road 10 accesses sampled voltage VRcs, the second input terminal 102 access reference voltage of input circuit 10
Vref.First output terminal 103 of input circuit 10 is connected with the first input end 201 of Current Voltage conversion circuit 20, input electricity
Second output terminal 104 on road 10 is connected with the second input terminal 202 of Current Voltage conversion circuit.
Output circuit 40 includes first order output circuit 410 and second level output circuit 420.First order output circuit 410
Power end and the power end of second level output circuit 420 access supply voltage, first order output circuit 410 and the second level are defeated
The ground terminal for going out circuit 420 is grounded.The output terminal of first order output circuit 410 and the input terminal of second level output circuit 420
Connection, the output terminal output control voltage of second level output circuit 420.The output terminal of Current Voltage conversion circuit 20 is respectively with
The input terminal connection of level-one output circuit 410.The first control terminal 301 and Current Voltage conversion circuit 20 of voltage clamping circuit 30
Output terminal connection, the second control terminal 302 of voltage clamping circuit 30 and the 3rd control terminal 303 and first order output circuit 410
Output terminal connection, the output terminal of second level output circuit 420 is the output terminal of voltage comparator.
When sampled voltage VRcs is less than reference voltage Vref, the first of the first output terminal 103 output of input circuit 10
Current signal is more than the second current signal of 10 second output terminal 104 of input circuit output, 20 basis of Current Voltage conversion circuit
It is zero that first current signal and the second current signal, which control the first node voltage vo1 of 20 output terminal of Current Voltage conversion circuit,
Voltage clamping circuit 30 controls the section point voltage vo2 of the output terminal of first order input circuit 410 in the first predeterminated voltage
Value, the first preset voltage value are less than supply voltage, and the voltage vo3 that controls of the output terminal output of second level output circuit is zero.
When sampled voltage VRcs reaches reference voltage Vref, the first of the first output terminal 103 output of input circuit 10
Current signal is more than the second current signal of 10 second output terminal 104 of input circuit output, 20 basis of Current Voltage conversion circuit
The first node voltage vo1 of 20 output terminal of first current signal and the second current signal control Current Voltage conversion circuit is by zero
Begin to ramp up, voltage clamping circuit 30 is pre- in the second preset voltage value, second by the rising peak control of first node voltage vo1
If magnitude of voltage is less than supply voltage, the section point voltage vo2 of the output terminal of first order input circuit 410 is by the first predeterminated voltage
Value drops to zero, and the output control voltage vo3 of the output terminal of second level output circuit 410 is supply voltage.
It should be noted that：The first preset voltage value and the second preset voltage value in the present embodiment can be different, also may be used
With identical, such as the first preset voltage value and the second preset voltage value are at or about the half of supply voltage.
It was found from above-described embodiment, by setting voltage clamping circuit in a comparator, it is less than in sampled voltage with reference to electricity
During pressure, voltage clamping circuit controls the section point voltage of the output terminal of first order input circuit in the first preset voltage value,
And first preset voltage value be less than the supply voltage；When sampled voltage is more than reference voltage, Current Voltage conversion circuit is defeated
The first node voltage of outlet is begun to ramp up by zero, and voltage clamping circuit controls the rising peak of first node voltage second
Preset voltage value, the second preset voltage value are less than the supply voltage, due to first node voltage and section point voltage not
With rising to supply voltage, it becomes possible to so that comparator output control voltage, shorten the response time of voltage comparator.
With reference to figure 2, Fig. 2 is a kind of electrical block diagram for voltage comparator that the utility model embodiment provides.For
Easy to explanation, illustrate only with the utility model relevant part, details are as follows：
As a preferred embodiment of the utility model, voltage clamping circuit 30 includes：First NMOS pipes 31 and second
NMOS tube 32.
The grid of the source electrode of first NMOS tube 31, the drain electrode of the second NMOS tube 32 and the second NMOS tube 32 respectively with electric current
The output terminal connection of voltage conversion circuit 20, the drain electrode of the first NMOS tube 31, the grid of the first NMOS tube 31 and the second NMOS tube
The output terminal connection of 32 source electrode difference first order output circuit 410.
As a preferred embodiment of the utility model, input circuit 10 includes：First PMOS tube 11, the second PMOS tube
12 and the 3rd PMOS tube 13.
First PMOS tube 11 source electrode access supply voltage, the first PMOS tube 11 drain electrode respectively with the second PMOS tube 12
Source electrode and the connection of the source electrode of the 3rd PMOS tube 13, the grid access first control signal vb1 of the first PMOS tube 11；Second PMOS tube
12 grid access sampled voltage, the grid access reference voltage of the 3rd PMOS pipes 13；The drain electrode of second PMOS tube 12 and electric current
The first input end connection of voltage conversion circuit 20, the drain electrode of the 3rd PMOS13 pipes and the second of Current Voltage conversion circuit 20
Input terminal connects.
As a preferred embodiment of the utility model, Current Voltage conversion circuit 20 includes：4th PMOS tube 21,
5th PMOS tube 22, the 6th PMOS tube 23, the 7th PMOS tube 24, the 3rd NMOS tube 25, the 4th NMOS tube 26, the 5th NMOS tube
27 and the 6th NMOS tube 28.
The source electrode of 4th PMOS tube 21 and the source electrode of the 5th PMOS tube 22 access supply voltage, the 4th PMOS tube 21
Drain and gate is connected respectively at the grid of the 5th PMOS tube 22, and the drain and gate of the 4th PMOS tube 21 is respectively with the 6th
The source electrode connection of PMOS tube 23, the drain electrode of the 5th PMOS tube 22 are connected with the source electrode of the 7th PMOS tube 24, the 6th PMOS tube 23
Grid of the drain and gate respectively with the 7th PMOS tube 24 is connected；
The drain electrode connection with the drain and gate of the 6th PMOS tube 23 respectively of 3rd NMOS tube 25, the 4th NMOS tube 26
Drain electrode is connected with the drain electrode of the 7th PMOS tube 24；The source electrode of 3rd NMOS tube 25 is connected with the drain electrode of the 5th NMOS tube 27, and the 4th
The source electrode of NMOS tube 26 is connected with the drain electrode of the 6th NMOS pipes 28, the grid of the 3rd NMOS tube 25 and the grid of the 4th NMOS tube 26
Extremely access second control signal vb2；The source electrode of 5th NMOS tube 27 and the source electrode of the 6th NMOS tube 28 are grounded respectively, and the 5th
The grid of NMOS tube 27 and the grid of the 6th NMOS tube 28 access the 3rd control signal vb3；
The source electrode of 3rd NMOS tube 25 and the common contact of the drain electrode of the 5th NMOS tube 27 are Current Voltage conversion circuit 20
The common contact of first input end, the source electrode of the 4th NMOS tube 26 and the drain electrode of the 6th NMOS tube 28 is Current Voltage conversion circuit 20
The second input terminal, the common contact of the drain electrode and the drain electrode of the 7th PMOS tube 24 of the 4th NMOS tube 26 is Current Voltage conversion circuit
20 output terminal.
As a preferred embodiment of the utility model, first order output circuit 410 includes 411 He of the 8th PMOS pipes
7th NMOS tube 412；Second level output circuit 420 includes the 9th PMOS tube 421 and the 8th NMOS tube 422.
The source electrode of 8th PMOS tube 411 and the source electrode of the 9th PMOS tube 421 access supply voltage, the 8th PMOS tube 411 altogether
Drain electrode be connected with the drain electrode of the 7th NMOS tube 412, drain electrode and the drain electrode of the 8th NMOS tube 422 of the 9th PMOS tube 421 connect
Connect, the grid of the 8th PMOS tube 411 and the grid of the 9th PMOS pipes 421 access the 4th control signal vb4 altogether；7th NMOS tube
The source electrode of 412 source electrode and the 8th NMOS pipes 422 is grounded altogether.
The grid of 7th NMOS tube 412 be first order output circuit 410 input terminal, the drain electrode of the 8th PMOS pipes 411 with
The drain electrode of 7th NMOS tube 412 altogether contact be first order output circuit 410 output terminal, the grid of the 8th NMOS tube 422 is the
The input terminal of two level output circuit 420, the common contact of drain electrode with the drain electrode of the 8th NMOS tube 422 of the 9th PMOS pipes 421 are the
The output terminal of two level output circuit 420.
As a preferred embodiment of the utility model, above-mentioned first order output circuit, can also include：First is anti-
Phase device A1 and the second phase inverter A2, the first phase inverter A1 connect with the second phase inverter A2, the first phase inverter A1
Input terminal access the 9th PMOS tube 421 drain electrode and the drain electrode of the 8th NMOS tube 422 common contact.
It should be noted that：The delay time for the voltage comparator that the utility model embodiment provides is 25nS, much small
In the delay time of the 53.5nS of common voltage comparator.
With reference to a kind of electrical block diagram for control chip that figure 2 and 3, Fig. 3 are the utility model embodiment offer.For
Easy to explanation, to illustrate only include with the relevant part of the utility model, the control chip 200 of the present embodiment：Above-mentioned implementation
Example voltage comparator 100, with door 210, nor gate 220, PWM modules 230, drive circuit 240, sampling resistor Rcs250 and
Power tube 260.
The output terminal of voltage comparator 100 is connected with the first input end of door 210, and the second input with door 210 terminates
Enter LEB shielded signals, be connected with the output terminal of door 210 with the first input end of PWM module 230.First input of nor gate 220
Terminate into OSC clock signals, the first input end ground connection GND of nor gate 220, output terminal and the PWM module 230 of nor gate 220
The second input terminal connection；The output terminal of PWM modules 230 is connected with the input terminal of drive circuit 240, drive circuit 240 it is defeated
Outlet is connected with the grid of power tube 260.The drain electrode access input voltage of power tube 260, source electrode and the sampling electricity of power tube 260
Hinder one end connection of Rcs250, the other end ground connection of sampling resistor 250, the source electrode of power tube 260 and connecing altogether for sampling resistor 250
Point is connected with the first input end of voltage comparator 100.Drive circuit is voltage amplifier circuit, and power tube 260 is NMOS tube.
With reference to a kind of electrical block diagram for Switching Power Supply that figure 3 and 4, Fig. 4 are the utility model embodiment offer.For
Easy to explanation, to illustrate only include with the relevant part of the utility model, the Switching Power Supply 300 of the present embodiment：Control chip
200th, input capacitance 310, chip power supply capacitance 320, energy storage inductor 330, fly-wheel diode 340, output feedback diode 350,
Output capacitance 360 and load resistance 370.
The first input end VIN of the drain electrode chip in order to control of the power tube 260 of control chip 200, control chip 200 also wrap
The second input terminal VCC is included, for accessing the power supply that chip 200 is powered in order to control, the sampling resistor 250 of control chip 200 connects
The ground terminal GND of ground terminal chip 200 in order to control.
One end access supply voltage of input capacitance 310, the other end ground connection of input capacitance；Control chip 200 first is defeated
Enter to hold VIN to access input voltage, the second input terminal VCC of control chip 200 is connected with exporting the cathode of feedback diode 350,
The ground terminal GND of control chip 200 is connected with one end of energy storage inductor 330, the other end and the output feedback two of energy storage inductor 330
The anode connection of pole pipe 350.
Chip power supply capacitance 320 is connected on the second input terminal and output 350 cathode of feedback diode of control chip 200
Altogether between contact and the ground terminal of control chip 200 and the common contact of energy storage inductor 330.The cathode access of fly-wheel diode 340
The common contact of chip power supply capacitance 320 and energy storage inductor 330, the plus earth of fly-wheel diode 340.Output capacitance 360 is with bearing
Carry common contact of one end access energy storage inductor 330 in parallel of resistance 370 with exporting feedback diode 350, output capacitance 360 with
The other end ground connection in parallel of load resistance 370, the both ends of load resistance 370 are the output terminal of the Switching Power Supply.Wherein power
Voltage is alternating voltage, and the both ends of load resistance 370 are respectively the positive and negative anodes output terminal of Switching Power Supply 300.
In a concrete application example, power switch can be BUCK type AC-DC Switching Power Supplies.With reference to figure 3 and 4, work(
The unlatching of rate pipe 260 is to export what open signal was performed fighting out by internal clock signal OSC controls PWM module 230；Power tube
260 closing is when detecting that VRcs reaches reference voltage Vref by sampling Rcs by comparator 100, and the output of comparator 100 is closed
Disconnected control signal exports reset signal and carrys out switch-off power pipe 260 to PWM module 230, PWM module 230.Power tube 260 is closed
When, the inductor current value Iocp=Vref/Rcs of energy storage inductor 330.
For the AC-DC Switching Power Supplies of a perfect condition, the waveform of energy storage inductor inductive current is as shown in Fig. 5：Wherein
I1And I2The different current waveform of the corresponding rate of rise, its peak value under respectively high, different input line voltages (supply voltage)
The threshold value of the Iocp set with inside is completely the same, and it is AC-D Switching Power Supplies that can be expressed as IL=(V/L) * T, wherein V
Input line voltage, L are the inductance values of energy storage inductor 330, and T is the inductor current value of the energy storage inductor in a switch periods from first
Initial point rises to the Iocp required times.
For the AC-DC Switching Power Supplies of a virtual condition, the inductive current of energy storage inductor can be expressed as：IL=V/
L*T+V/L*Td, wherein, Td is (to reach reference voltage Vref equivalent to sampled voltage VRcs) when inductive current reaches Iocp to arrive
Delay between power tube shut-off.Since Td exists, the inductive current of energy storage inductor is generation Δ I=(V/L) TdError, and
Error and input line voltage and delay Td direct proportionalities, Td is fixed for a known AC-DC Switching Power Supply
's.With reference to figure 6, the waveform of the inductive current of energy storage inductor under virtual condition, it is known that input line voltage is bigger, inductive current error
Bigger, the smaller inductive current error of input line voltage is smaller.
Wherein, Td=Tcomp+Tds, Tcomp is the corresponding time of voltage comparator in formula, and Tds closes for comparator output
The grid required time of disconnected control signal Vcomp to power tube 260.Mainly there is logic circuit (voltage ratio due to Tds
Compared with device 100, with door 210, nor gate 220, PWM module 230) and drive circuit delay composition, therefore without too big optimization
Space.Effect biggers of the corresponding time Tcomp of voltage comparator to Td.
For the AC-DC Switching Power Supplies under virtual condition, when output loading changes from small to large, inductive current will be from
DCM (Discontinuous Current Mode, discontinuous conduct mode) pattern enters CCM (Continuous Current
Mode, continuous current mode) pattern.With reference to figure 7, when input line voltage is smaller, the inductive current caused by above-mentioned Tcomp
Error delta IL1It is smaller, IL1The peak point current Ipeak1 in CCM periods there is preferable uniformity；When input line voltage is larger
When, the inductive current error delta I caused by above-mentioned TcompL2It is larger, IL2The peak point current Ipeak2 in CCM periods one
Cause property is poor.Understand, when input line voltage is higher, each switch periods are more than input line electricity to the energy that energy storage inductor stores
The energy stored when pressing relatively low, so that cause the load capacity of system output smaller in low input line voltage, original text input line
Voltage is larger.
With reference to figure 8, Fig. 8 is different input voltage V1, the input voltage V2 of voltage comparator and the mistake of input voltage V3
Carry the correspondence of Iload protections point.Wherein, Iload1 and Iload2 is the overload protection point of common comparator；Iload1 and
Iload2 is the overload protection point of the voltage comparator of the utility model embodiment.It can be seen that the electricity that the utility model embodiment provides
Pressure comparator enables to the overload protection point of Switching Power Supply to the security for good uniformity, strengthening Switching Power Supply.It is general
The delay time of logical comparator is 53.5nS, and the delay time of the comparator of the utility model is 25nS.It can be seen that the utility model
Comparator, substantially increase response speed.
The above, is only specific embodiment of the present utility model, but the scope of protection of the utility model is not limited to
In this, any one skilled in the art can readily occur in various in the technical scope that the utility model discloses
Equivalent modifications or substitutions, these modifications or substitutions should be covered within the scope of the utility model.Therefore, this practicality
New protection domain should be subject to scope of the claims.
Claims (10)
- A kind of 1. voltage comparator, it is characterised in that including：Input circuit, Current Voltage conversion circuit, voltage clamping circuit and Output circuit；The power end of the power end of the input circuit, the power end of the Current Voltage conversion circuit and the output circuit is equal Same supply voltage is accessed, the ground terminal of the Current Voltage conversion circuit and the ground terminal of the output circuit are grounded；Institute State the first input end access sampled voltage of input circuit, the second input terminal access reference voltage of input circuit；The input First output terminal of circuit is connected with the first input end of the Current Voltage conversion circuit, the second output of the input circuit End is connected with the second input terminal of the Current Voltage conversion circuit；The output circuit includes first order output circuit and second level output circuit, the power end of the first order output circuit The supply voltage, the first order output circuit and second level output circuit are accessed with the power end of second level output circuit Ground terminal be grounded, the output terminal of the first order output circuit is connected with the input terminal of the second level output circuit, institute State the output terminal output control voltage of second level output circuit；The output terminal of the Current Voltage conversion circuit is respectively with described The input terminal of level-one output circuit is connected with the first control terminal of the voltage clamping circuit, and the second of the voltage clamping circuit The output terminal of control terminal and the 3rd control terminal respectively with the first order output circuit is connected.
- 2. voltage comparator according to claim 1, it is characterised in that the voltage clamping circuit includes：First NMOS Pipe and the second NMOS tube；The grid of the source electrode of first NMOS tube, the drain electrode of second NMOS tube and second NMOS tube respectively with it is described The output terminal connection of Current Voltage conversion circuit, the draining of first NMOS tube, the grid of first NMOS tube and described The source electrode of second NMOS tube distinguishes the output terminal connection of the first order output circuit.
- 3. voltage comparator according to claim 1, it is characterised in that the input circuit includes：First PMOS tube, Two PMOS tube and the 3rd PMOS tube；The source electrode of first PMOS tube accesses the supply voltage, and the drain electrode of first PMOS tube is respectively with described second The source electrode of PMOS tube and the connection of the source electrode of the 3rd PMOS tube, the grid access first control signal of first PMOS tube are described The grid of second PMOS tube accesses the sampled voltage, and the grid of the 3rd PMOS tube accesses the reference voltage, and described the The drain electrode of two PMOS tube is connected with the first input end of the Current Voltage conversion circuit, the drain electrode of the 3rd PMOS tube and institute State the second input terminal connection of Current Voltage conversion circuit.
- 4. voltage comparator according to claim 1, it is characterised in that the Current Voltage conversion circuit includes：4th PMOS tube, the 5th PMOS tube, the 6th PMOS tube, the 7th PMOS tube, the 3rd NMOS tube, the 4th NMOS tube, the 5th NMOS tube and 6th NMOS tube；The source electrode of 4th PMOS tube and the source electrode of the 5th PMOS tube access the supply voltage, the 4th PMOS Grid of the drain and gate of pipe respectively with the 5th PMOS tube is connected, the drain and gate of the 4th PMOS tube respectively with The source electrode connection of 6th PMOS tube, the drain electrode of the 5th PMOS tube is connected with the source electrode of the 7th PMOS tube, described Grid of the drain and gate of 6th PMOS tube respectively with the 7th PMOS tube is connected；The drain electrode connection with the drain and gate of the 6th PMOS tube respectively of 3rd NMOS tube, the 4th NMOS tube Drain electrode be connected with the drain electrode of the 7th PMOS tube；The source electrode of 3rd NMOS tube connects with the drain electrode of the 5th NMOS tube Connect, the source electrode of the 4th NMOS tube is connected with the drain electrode of the 6th NMOS tube, the grid and the 4th NMOS of the 3rd NMOS tube The grid of pipe accesses second control signal；The source electrode of 5th NMOS tube and the source electrode of the 6th NMOS tube are grounded respectively, institute State the grid of the 5th NMOS tube and the grid of the 6th NMOS tube accesses the 3rd control signal；The source electrode of 3rd NMOS tube and the common contact of the drain electrode of the 5th NMOS tube are the Current Voltage conversion circuit First input end, the common contact of the source electrode of the 4th NMOS tube and the drain electrode of the 6th NMOS tube is the Current Voltage Second input terminal of conversion circuit, the common contact of the drain electrode and the drain electrode of the 7th PMOS tube of the 4th NMOS tube is described The output terminal of Current Voltage conversion circuit.
- 5. voltage comparator according to claim 1, it is characterised in that the first order output circuit includes the 8th PMOS Pipe and the 7th NMOS tube, the second level output circuit include the 9th PMOS tube and the 8th NMOS tube；The source electrode of 8th PMOS tube and the source electrode of the 9th PMOS tube access the supply voltage, the 8th PMOS The drain electrode of pipe is connected with the drain electrode of the 7th NMOS tube, the drain electrode and the drain electrode of the 8th NMOS tube of the 9th PMOS tube Connection, the grid of the 8th PMOS tube and the grid of the 9th PMOS tube access the 4th control signal；Described 7th The source grounding of the source electrode of NMOS tube and the 8th NMOS tube；The grid of 7th NMOS tube is the input terminal of the first order output circuit, the drain electrode of the 8th PMOS tube and institute The common contact of drain electrode for stating the 7th NMOS tube is the output terminal of the first order output circuit, and the grid of the 8th NMOS tube is institute The input terminal of second level output circuit is stated, the common contact of the drain electrode and the drain electrode of the 8th NMOS tube of the 9th PMOS tube is The output terminal of the second level output circuit.
- 6. voltage comparator according to claim 5, it is characterised in that the first order output circuit further includes：First Phase inverter and the second phase inverter, first phase inverter and second inverter series, the input terminal of first phase inverter Access the common contact of the drain electrode and the drain electrode of the 8th NMOS tube of the 9th PMOS tube.
- 7. a kind of control chip, it is characterised in that including such as claim 1 to 6 any one of them voltage comparator, also wrap Include：With door, nor gate, PWM module, drive circuit, sampling resistor and power tube；The output terminal of the voltage comparator is connected with described with the first input end of door, described to be accessed with the second input terminal of door LEB shielded signals, it is described to be connected with the output terminal of door with the first input end of the PWM module；The first of the nor gate is defeated Enter to terminate and be grounded into OSC clock signals, the first input end of the nor gate, the output terminal of the nor gate and the PWM moulds The second input terminal connection of block；The output terminal of the PWM module is connected with the input terminal of the drive circuit, the drive circuit Output terminal be connected with the grid of the power tube, the drain electrode of power tube access input voltage, the source electrode of the power tube It is connected with one end of the sampling resistor, the other end ground connection of the sampling resistor, the source electrode of the power tube and the sampling The common contact of resistance is connected with the first input end of the voltage comparator.
- 8. control chip according to claim 7, it is characterised in that the power tube is NMOS tube.
- 9. a kind of Switching Power Supply, it is characterised in that including such as 7 or 8 any one of them control chip of claim, further include： Input capacitance, chip power supply capacitance, energy storage inductor, fly-wheel diode, output feedback diode, output capacitance and load resistance；The drain electrode of the power tube of the control chip is the first input end of the control chip, and the control chip further includes the Two input terminals, for accessing the power supply of chip power supply in order to control, the ground terminal of the sampling resistor of the control chip is the control The ground terminal of coremaking piece；One end access supply voltage of the input capacitance, the other end ground connection of the input capacitance；The control chip first Input terminal accesses input voltage, and the second input terminal of the control chip is connected with the cathode of the output feedback diode, institute The ground terminal for stating control chip is connected with one end of the energy storage inductor, and the other end of the energy storage inductor is fed back with the output The anode connection of diode；The chip power supply capacitance is connected on the second input terminal of the control chip and being total to for the output feedback diode cathode Between the common contact of the ground terminal and the energy storage inductor of contact and the control chip；The cathode access of the fly-wheel diode The common contact of the chip power supply capacitance and energy storage inductor, the plus earth of the fly-wheel diode；The output capacitance and institute The common contact of the energy storage inductor and output feedback diode, the output capacitance and institute are accessed in the one end for stating load resistance parallel connection The other end ground connection of load resistance parallel connection is stated, the both ends of the load resistance are the output terminal of the Switching Power Supply.
- 10. Switching Power Supply according to claim 9, it is characterised in that the supply voltage is alternating voltage, the switch The output terminal of power supply is the positive and negative anodes output terminal of output direct current.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721094325.6U CN207234647U (en) | 2017-08-29 | 2017-08-29 | Voltage comparator, control chip and Switching Power Supply |
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| CN201721094325.6U CN207234647U (en) | 2017-08-29 | 2017-08-29 | Voltage comparator, control chip and Switching Power Supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107528450A (en) * | 2017-08-29 | 2017-12-29 | 深圳市稳先微电子有限公司 | Voltage comparator, control chip and Switching Power Supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107528450A (en) * | 2017-08-29 | 2017-12-29 | 深圳市稳先微电子有限公司 | Voltage comparator, control chip and Switching Power Supply |
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