CN202513824U - Cross-mode high-and-low voltage compensation device - Google Patents

Abstract

The utility model provides a cross-mode high-and-low voltage compensation device including a sampling module, an operating module and a comparing module. The sampling module is used for sampling electric signals on a current detecting resistor, thereby obtaining a reference signal D1. The operating module is used for operating the reference signal D1 and the reference signal D2, thereby obtaining a product of (D1+D2) and (D1-D2). The comparing module compares the product of (D1+D2) and (D1-D2) with a reference value D0, and outputs current-limiting control enabling EN_OSC to control the switching of a power MOSFET switch tube. According to the scheme provided by the utility model, the maximum output power in two working modes of a current continuous mode and a current interrupted mode is kept constant through controlling the maximum variable quantity of inductive current in primary side winding of a transformer.

Description

The high-low pressure compensation arrangement of cross-module formula

Technical field

The utility model relates to the switch power technology field, and particularly, the utility model relates to the high-low pressure compensation arrangement of cross-module formula.

Background technology

In current mode PWM application of switching power field, (for example, 85V～265V) Maximum Power Output of the interior system of input range is consistent at wide voltage in requirement.Fig. 1 is traditional current mode PWM chip inverse-excitation type application system; In normal working conditions; System compares with TL431 error discharger through detecting output, obtains the FB signal through the optocoupler feedback, and FB signal and peak current are realized PWM control through the PWM_COMP comparator then.When output loading aggravated, the OC_COMP comparator worked, and it defines the peak power output of system, thereby had protected system.In this application circuit, inspection leakage resistance R _SOn voltage through behind the lead-edge-blanking circuit with feedback voltage FB and current limliting reference voltage V _{OC_REF}Compare the opening time of power controlling switch mosfet.Feedback voltage FB becomes along with the rising of load greatly, and when load rises to full load, FB reaches maximum and FB=V _{OC_REF}, that is to say, when load reaches maximum, the opening time T of power mosfet switch _OnReach maximum, and power output reaches maximum.Because current limliting reference voltage V _{OC_REF}It is a definite value; So the current maxima on the power MOSFET switch tube electric current continuously with all be identical under two kinds of mode of operations of discontinuous current; Peak power output under two kinds of mode of operations of event is different, and the electric current continuous operation mode is littler than the peak power output of discontinuous current mode of operation.

Expression formula in discontinuous mode power output of following time does,

$P_{\mathrm{out}}=\frac{1}{2}\·L\·I^2\·f\·\mathrm{\η}=\frac{1}{2}\·\frac{{(V_{\mathrm{dc}}\·T_{\mathrm{on}})}^2}{L}\·f\·\mathrm{\η}---\left(1\right)$

Wherein, Ton is the opening time of power switch pipe.

Can know according to formula, when L and f are certain, as input voltage V _DCHour, for keeping power output, the value of ON time Ton will increase, and the time T on of inductive energy storage is greater than the erasing time in reverse excitation circuit, and system will be operated in continuous current mode, and its current peak waveform is shown in Fig. 2 (a); As input voltage V _DCWhen big, circuit working is in the discontinuous current pattern, and its current peak waveform is shown in Fig. 2 (b);

According to the relation of energy, the power output expression formula is adjusted under continuous mode

$P_{\mathrm{out}}=\frac{1}{2}\·L\·(i_1^2-i_0^2)\·f\·\mathrm{\η};$

If system works is continuous and two kinds of mode of operations of discontinuous current at electric current, can see Δ i=I in the continuous current mode by Fig. 2 ₁-I ₀, Δ i=I in the discontinuous current pattern ₂In a switch periods, the peak value of the power output of switching power circuit and change in current amount Δ i and the difference of two squares of minimum are proportional.

In the system of practical application; Owing to when wide voltage is imported, can be operated in two kinds of mode of operations under a lot of situation of system; When low input, be in continuous mode (CCM); When high input voltage, be in discontinuous mode (DCM), the current peak waveform under the different mode is as shown in Figure 2, because OCP current limliting reference voltage V _{OC_REF}Be a definite value, the maximum power that the maximum power of exporting when causing high pressure is exported during much larger than low pressure is difficult to satisfy the requirement that peak power output is consistent in wide input voltage range.For reaching above-mentioned requirement, need maximum limit flow valuve to the mode of operation Adjustment System of system.

Therefore, be necessary to propose the otherwise effective technique scheme, solution can make system under continuous mode and discontinuous mode condition, can both keep the consistent problem of peak power output.

The utility model content

The purpose of the utility model is intended to solve at least one of above-mentioned technological deficiency; Special in the maximum variable quantity of the inductive current in the winding of the former limit of control transformer, make that peak power output keeps constant in continuous current mode and two kinds of mode of operations of discontinuous current pattern because the pass of different input voltages ties up in system.

The utility model embodiment has proposed a kind of constant maximum power output adjusting device of cross-module formula, comprises sampling module, computing module and comparison module,

Said sampling module is used for the signal of telecommunication on the inspection leakage resistance is sampled, and obtains reference signal D1;

Said computing module, be used for to said reference signal D1 with follow signal D2 and carry out computing, obtain (D1+D2) and (D1-D2) product;

Said comparison module is used for said (D1+D2) and product (D1-D2) and fiducial value D0 are compared, and output current limiting control enables the unlatching of EN_OSC power controlling switch mosfet pipe.

The such scheme that the utility model embodiment proposes; Through the maximum variable quantity of the inductive current in the winding of the former limit of control transformer, make that peak power output keeps constant in continuous current mode and two kinds of mode of operations of discontinuous current pattern because the pass of different input voltages ties up in system.In addition, the such scheme that the utility model proposes need not changed the peripheral circuit of switching power source chip, can not influence the compatibility of system, and realize simple, efficient.

Aspect that the utility model is additional and advantage part in the following description provide, and these will become obviously from the following description, or recognize through the practice of the utility model.

Description of drawings

Above-mentioned and/or additional aspect of the utility model and advantage are from obviously with easily understanding becoming the description of embodiment below in conjunction with accompanying drawing, wherein:

Fig. 1 is typical application of switching power scheme;

Fig. 2 is that electric current changes sketch map under two kinds of patterns;

Fig. 3 is the utility model embodiment circuit structure block diagram;

Fig. 4 is the constant maximum power output adjusting device physical circuit figure of the utility model embodiment cross-module formula;

Fig. 5 is the constant maximum power output adjusting device application scheme of the utility model embodiment cross-module formula.

Embodiment

Describe the embodiment of the utility model below in detail, the example of said embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Be exemplary through the embodiment that is described with reference to the drawings below, only be used to explain the utility model, and can not be interpreted as restriction the utility model.

In order to realize the purpose of the utility model, the utility model embodiment has proposed a kind of constant maximum power output adjusting device of cross-module formula, comprises sampling module, computing module and comparison module,

Said sampling module is used for the signal of telecommunication on the inspection leakage resistance is sampled, and obtains reference signal D1;

Said computing module, be used for to said reference signal D1 with follow signal D2 and carry out computing, obtain (D1+D2) and (D1-D2) product;

Said comparison module is used for said (D1+D2) and product (D1-D2) and fiducial value D0 are compared, and output current limiting control enables the unlatching of EN_OSC power controlling switch mosfet pipe.

Wherein, follow signal D2 and directly come from input signal Vs (as shown in Figure 3), but need be converted into the attribute identical, be all curtage with fiducial value D0.

Particularly, the attribute of promptly said reference signal D1 and D2 is identical with the attribute of fiducial value D0, is voltage or current value.

When sample information or follow signal and the attribute of said D0 when inequality, be that electric current or current conversion are voltage for example through voltage transitions, the reference signal D1 that obtains same alike result with follow signal D2.

As the embodiment of the utility model, said computing module comprises adder circuit and multiplies each other circuit.

As the embodiment of the utility model, said adder circuit is realized through the current operator circuit with the circuit that multiplies each other.

As the embodiment of the utility model, said comparison module comprises comparator.

In order further to set forth the utility model, the utility model is described further below in conjunction with physical circuit.

As the embodiment of the utility model, the utility model circuit design comprises current summation and multiplies each other circuit and current comparison circuit, as input voltage V _DCDiminish when making the circuit working pattern become continuous current mode, improve the current-limiting points electric current, peak power output is remained unchanged by the discontinuous current pattern.

The input average power is in the circuit:

$P_I=\frac{1}{T}{\∫}_0^{T}u\left(t\right)i\left(t\right)\mathrm{dt}---\left(2\right)$

$u\left(t\right)=L\frac{\mathrm{di}\left(t\right)}{\mathrm{dt}}---\left(3\right)$

Get by formula (2) and (3):

$P_I=\frac{L}{2T}{i}^2\left(t\right){|}_0^T---\left(4\right)$

Can find out continuous current mode by Fig. 2:

$P_I=\frac{L}{2T}(i_1^2-i_0^2)=\frac{L}{2T}(i_1+i_0)(i_1-i_0)---\left(5\right)$

Can find out by formula (5), as long as (i ₁+ i ₀) * (i ₁-i ₀) be a constant, so just can make under the continuous current mode peak power output identical with the discontinuous current pattern.

The circuit structure block diagram of the utility model is as shown in Figure 3, inspection leakage resistance R _SOn voltage V _SProduce electric current D through over-sampling and through voltage one current converter circuit ₁And D ₂, produce (D through the adder circuit and the circuit that multiplies each other then ₁+ D ₂) * (D ₁-D ₂) final and benchmark D ₀Compare, output current limiting control enables the opening time of EN_OSC power controlling switch mosfet pipe.The utility model can realize that through the maximum limit flow valuve of Adjustment System switching power circuit is constant at continuous current mode and these two kinds of mode of operation peak power outputs of discontinuous current pattern when input voltage changes.

The utility model circuit implementation can be by shown in Figure 4.Inspection leakage resistance voltage V _SProduce electric current I through over-sampling and U_I change-over circuit ₀, produce electric current I through the U_I change-over circuit simultaneously ₁, produce two current summation (I through current mirror and computing then ₁+ I ₀) and subtract each other (I ₁-I ₀), utilize multiplier to multiply each other at last.Below be about use in the circuit the explanation of multiplier.

According to transistor characteristic:

$V_{\mathrm{BE}}=V_T\ln \frac{V_C}{V_S}---\left(6\right)$

Four transistor Q1～Q4 can find out in the circuit:

V _BE1+V _BE2＝V _BE3+V _BE4(7)

Formula (6) substitution formula 7 is got:

I _C1×I _C2＝I _C3×I _C4(8)

That is:

(I ₁+ I ₀) * (I ₁One I ₀)=I _C* I _O(9)

So can obtain:

$I_O=\frac{(I_1+I_0)\×(I_1-I_0)}{I_C}---\left(10\right)$

At last to I _OAnd I _CCompare, work as I _O＞I _CThe time, that is:

$({\mathrm{<figure-callout\; id="1"\; label="I"\; filenames="HDA0000111916530000012.png"\; state="\{\{state\}\}">I</figure-callout>}}_1+I_0)(I_1-I_0)>I_C^2---\left(11\right)$

Output enable EN_OC is a high level; Otherwise be low level.

Fig. 4 circuit has been accomplished the computing to the cut-off current of circuit system when the different mode, guarantees (i ₁+ i ₀) * (i ₁-i ₀) be a constant, realized that switch power supply current continuous mode and discontinuous current pattern peak power output are constant.

In the above-mentioned example, reference signal, follow signal, fiducial value is current value.Obviously, fiducial value also can be magnitude of voltage, and reference signal, to follow signal demand consistent with the fiducial value attribute or through consistent getting final product after the conversion.

The circuit of the utility model can replace the current limliting comparator in the typical application of switching power scheme as shown in Figure 1, and is specifically as shown in Figure 5.In this application scheme, no matter Switching Power Supply is operated in continuous current mode still is the discontinuous current pattern, and it is constant that its peak power output can keep.

The such scheme that the utility model embodiment proposes; Through the maximum variable quantity of the inductive current in the winding of the former limit of control transformer, make that peak power output keeps constant in continuous current mode and two kinds of mode of operations of discontinuous current pattern because the pass of different input voltages ties up in system.In addition, the such scheme that the utility model proposes need not changed the peripheral circuit of switching power source chip, can not influence the compatibility of system, and realize simple, efficient.

Though specify about example embodiment and advantage thereof, be to be understood that under the situation of the protection range that the spirit that does not break away from the utility model and accompanying claims limit, can carry out various variations, replacement and modification to these embodiment.For other examples, when those of ordinary skill in the art should understand easily in keeping the utility model protection range, the order of processing step can change.

In addition, the range of application of the utility model is not limited to technology, mechanism, manufacturing, material composition, means, scheme and the step of the specific embodiment of describing in the specification.Disclosure from the utility model; To easily understand as those of ordinary skill in the art; For the technology, mechanism, manufacturing, material composition, means, scheme or the step that have existed or be about to later on develop at present; Wherein they are carried out the corresponding embodiment cardinal principle identical functions of describing with the utility model or obtain identical substantially result, can use them according to the utility model.

Therefore, the utility model accompanying claims is intended to these technology, mechanism, manufacturing, material composition, means, scheme or step are included in its protection range.Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the utility model principle, can also make some improvement and retouching, these improvement and retouching also should be regarded as the protection range of the utility model.

Claims (6)

1. the high-low pressure compensation arrangement of a cross-module formula is characterized in that, comprises sampling module, computing module and comparison module,

Said sampling module is used for the signal of telecommunication on the inspection leakage resistance is sampled, and obtains reference signal D1;

Said computing module, be used for to said reference signal D1 with follow signal D2 and carry out computing, obtain (D1+D2) and (D1-D2) product;

Said comparison module is used for said (D1+D2) and product (D1-D2) and fiducial value D0 are compared, and output current limiting control enables the unlatching of EN_OSC power controlling switch mosfet pipe.

2. the high-low pressure compensation arrangement of cross-module formula as claimed in claim 1 is characterized in that, said reference signal D1 is identical with the attribute of fiducial value D0 with the attribute of following signal D2, is voltage or current value.

3. the high-low pressure compensation arrangement of cross-module formula as claimed in claim 2; It is characterized in that; When sample information or follow the attribute of signal D2 and said D0 when inequality, be that electric current or current conversion are voltage through voltage transitions, the reference signal D1 that obtains same alike result with follow signal D2.

4. the high-low pressure compensation arrangement of cross-module formula as claimed in claim 1 is characterized in that, said computing module comprises adder circuit and multiplies each other circuit.

5. the high-low pressure compensation arrangement of cross-module formula as claimed in claim 4 is characterized in that, said adder circuit is realized through the curtage computing circuit with the circuit that multiplies each other.

6. the high-low pressure compensation arrangement of cross-module formula as claimed in claim 1 is characterized in that said comparison module comprises comparator.

Images