CN202997919U - Ripple suppression circuit and power supply system thereof - Google Patents

Abstract

A ripple suppression circuit and a power supply system are provided. The ripple suppression circuit comprises a filter circuit and a follower circuit. The filter circuit is provided with an input end and an output end, the input end of the filter circuit is coupled with a voltage source, and the filter circuit filters the voltage source and outputs a filter voltage at the output end of the filter circuit. The follower circuit is provided with a first input end, a second input end and an output end, wherein the first input end of the follower circuit is coupled with a voltage source, the second input end of the follower circuit is coupled with the output end of the filter circuit, and the output end of the follower circuit provides an output signal for supplying energy to a load. The ripple suppression circuit has the advantages of long service life of the system, capability of reducing the capacitance value of the output capacitor, convenience and flexibility in control, strong adaptability and the like.

Description

A kind of ripple suppression circuit and electric power system thereof

Technical field

The utility model relates to electric power system, particularly but the electric power system and the output current ripple that are not limited to relate to for light-emitting diode suppress circuit.

Background technology

Light-emitting diode (LED) is widely used in illumination as a kind of low energy consumption, high efficiency luminescent material.In existing a kind of LED electric power system, adopt single-stage Active PFC (PFC) voltage conversion circuit to come driving LED, be the LED energy supply.But the direct current signal of single-stage PFC voltage conversion circuit output contains larger ripple.In order to reduce ripple, a kind of existing settling mode is for coupling the electrochemical capacitor of large capacitance at output.But the life-span of electrochemical capacitor is shorter, greatly is shorter than the life-span of LED, the life-span of adopting the large electric capacity of electrolysis can reduce whole electric power system.Simultaneously large electric capacity has also increased system bulk.

Therefore, be necessary to adopt little electric capacity, and the increase ripple suppression circuit reduces ripple.

The utility model content

In order to solve a previously described problem or a plurality of problem, the utility model proposes a kind of ripple suppression circuit and electric power system.

According to an aspect of the present utility model, a kind of ripple suppression circuit comprises: filter circuit, have input and output, wherein the input of filter circuit couples voltage source, and filter circuit carries out filtering with the voltage that contains ripple of voltage source and at the output output filtering voltage of filter circuit; And follow circuit, have first input end, the second input and output, wherein the first input end of follow circuit couples voltage source, the second input of follow circuit couples the output of filter circuit, the output of follow circuit provides output signal to be used to the load energy supply, and wherein output signal produces based on filtering voltage.Filter circuit can comprise: electric capacity, have first end and the second end, and wherein the first end of electric capacity couples the output of filter circuit, and the second end of electric capacity couples with reference to ground; And resistance, have first end and the second end, wherein the first end of resistance couples the input of filter circuit, the first end of the second end coupling capacitance of resistance.Follow circuit can comprise transistor, transistor has first end, the second end and control end, wherein transistorized first end couples the first input end of follow circuit, transistorized control end couples the second input of follow circuit, transistorized the second end couples the output of follow circuit, wherein output signal is the current signal that flows through transistor the second end, and current signal is followed the filtering voltage variation.Transistor can comprise Darlington transistor.Follow circuit can further comprise the second resistance, and the second resistance has first end and the second end, and wherein the first end of the second resistance couples the output of filter circuit, and the second end of the second resistance couples transistorized control end.

According to another aspect of the present utility model, a kind of electric power system comprises ripple suppression circuit as above, voltage source and load.Voltage source can comprise single-stage Active PFC voltage conversion circuit.Load can comprise the LED lamp.Above-mentioned electric power system can further comprise short-circuit protection circuit, and short-circuit protection circuit comprises: the 3rd resistance is coupled between the first input end and a node of follow circuit; The 4th resistance, and the series connection of the 3rd resistance, the 4th resistance is coupled between the output of node and follow circuit; The 3rd electric capacity, and the 4th resistance is in parallel, is coupled in the two ends of the 4th resistance; And switch, have first end, the second end and control end, wherein the first end of switch couples the second input of follow circuit, and the second end of switch couples the output of follow circuit, and the control end of switch couples node.

The ripple suppression circuit and the electric power system that provide according to embodiment of the present utility model have life-span length, reduce output capacitance appearance value, control the advantages such as convenient, flexible and strong adaptability.

Description of drawings

In order better to understand the utility model, will be described embodiment of the present utility model according to the following drawings:

Fig. 1 shows the electric power system schematic block diagram according to the utility model one embodiment;

Fig. 2 shows the ripple suppression circuit schematic diagram according to the utility model one embodiment;

Fig. 3 shows the ripple suppression circuit schematic diagram according to another embodiment of the utility model;

Fig. 4 shows the ripple suppression circuit schematic diagram according to the another embodiment of the utility model;

Fig. 5 shows according to the utility model ripple suppression circuit schematic diagram of an embodiment again;

Fig. 6 shows the electric power system schematic diagram according to the utility model one specific embodiment;

Fig. 7 shows the electric power system schematic diagram according to the utility model one embodiment, and wherein this electric power system comprises short-circuit protection circuit;

Accompanying drawing does not show all circuit or the structure of embodiment.Run through institute's identical Reference numeral of drawings attached and represent identical or similar parts or feature.

Embodiment

The below will describe specific embodiment of the utility model in detail, should be noted that the embodiments described herein only is used for illustrating, and be not limited to the utility model.To in detailed description of the present utility model, in order to understand better the utility model, a large amount of details has been described below.Yet it will be understood by those skilled in the art that does not have these details, and the utility model can be implemented equally.In order to set forth the utility model clearly, this paper has simplified the detailed description of some concrete structures and function.In addition, the similar 26S Proteasome Structure and Function of having described in detail in certain embodiments repeats no more in other embodiments.Although every term of the present utility model is to describe one by one in conjunction with concrete example embodiment, these terms should not be construed as the demonstration execution mode that is confined to set forth here.

" coupling " of mentioning in specification of the present utility model can refer to directly to connect or the connection by indirect thing, as the connection by conductor, this conductor has resistance, also parasitic parameter can be arranged, as have inductance value and capacitance, and as the connection by semiconductor device such as diode.

Fig. 1 shows electric power system 100 schematic diagrames according to the utility model one embodiment.Wherein electric power system 100 comprises voltage source 20, ripple suppression circuit 10 and load 30.

Voltage source 20 has output 22, and output 22 provides the voltage that contains ripple V _INVoltage source 20 can be any form, and as adapter, chip, circuit module even wire or other conductor etc., voltage source 20 provides the voltage that contains ripple.Ripple can have any waveform or size, as long as voltage waveform is not ideal line.In one embodiment, voltage source 20 comprises voltage conversion circuit, and voltage conversion circuit is used for a voltage transitions is become a direct current voltage Vin, in output 22 outputs.In one embodiment, voltage conversion circuit is used for converting alternating voltage to direct voltage Vin.In another embodiment, voltage conversion circuit is used for a direct current voltage transitions is become another direct voltage Vin.

Ripple suppression circuit 10 is coupled between voltage source 20 and load 30, and ripple suppression circuit 10 produces output signal OUT at output, the ripple that contains for reducing voltage source 20 voltage Vin, and give load 30 power supplies.Ripple suppression circuit 10 comprises filter circuit 11 and follow circuit 12.

Wherein filter circuit 11 carries out filtering for the voltage Vin that voltage source 20 is provided, and produces filtering voltage Vc at the output 112 of filter circuit 11.Therefore, the ripple of filtering voltage Vc is less than the ripple of voltage Vin.Filter circuit 11 has input 111 and output 112.Input 111 couples voltage source 20, is used for receiving the voltage Vin that contains ripple.Output 112 provides the filtering voltage Vc of voltage Vin.Filtering voltage Vc follows the mean value of voltage Vin but relative voltage Vin, and filtering voltage Vc voltage waveform is more level and smooth, and its ripple composition is lowered.

Follow circuit 12 makes output signal OUT amplitude follow filtering voltage Vc variation, and namely its waveform or smoothness are followed filtering voltage Vc.Follow circuit 12 has first input end 121, the second input 122 and output 123, and wherein first input end 121 couples voltage source 20 for receiver voltage Vin, and the second input 122 couples the output 112 of filter circuit 11.The output 123 of follow circuit 12 couples load 30 and provides output signal OUT to be used to load 30 energy supplies.Wherein output signal OUT produces based on filtering voltage Vc, makes output signal OUT follow filtering voltage Vc and changes, and is therefore smoother, reduced ripple.In one embodiment, output signal OUT is magnitude of voltage, and the voltage of the output 123 of follow circuit 12 is directly proportional to filtering voltage Vc.In another embodiment, output signal OUT is current signal, and the electric current of the output 123 of follow circuit 12 is directly proportional to filtering voltage Vc.

In one embodiment, load 30 is the LED lamp string of a plurality of light-emitting diodes (LED) composition of series connection.In another embodiment, load 30 is the LED string of a plurality of parallel connections.In yet another embodiment, load 30 is single led.In other embodiments, load is the load that is different from single or multiple any connected modes of a plurality of LED of above-mentioned connected mode or other type.

Fig. 2 shows the schematic diagram according to the ripple suppression circuit 210 of the utility model one embodiment.Ripple suppression circuit 210 comprises filter circuit 11 and follow circuit 12.

Wherein filter circuit 11 comprises resistance R 1 and capacitor C 2.Capacitor C 2 has first end 211 and the second end 212, and wherein first end 211 couples the output 112 of filter circuit 11 and the second input 122 of follow circuit 12, and the second end 212 of capacitor C 2 couples with reference to ground GND.Resistance R 1 has first end 131 and the second end 132, and wherein the first end 131 of resistance R 1 couples input 111 and the voltage source of filter circuit 11, the first end 211 of the second end 132 coupling capacitance C2 of resistance R 1 and the output 112 of filter circuit 11.The filter circuit 11 that is comprised of resistance R 1 and capacitor C 2 is at output 112 output filtering voltage Vc.The mean value of filtering voltage Vc reflection node IN voltage Vin, but relative voltage Vin, filtering voltage Vc waveform is more level and smooth, and its ripple composition is lowered.In some other embodiment, filter circuit 11 has the structure of other form.In one embodiment, filter circuit 11 comprises the filter circuit network that is comprised of a plurality of electric capacity and a plurality of resistance.In one embodiment, capacitor C 2 and resistance R 1 size are adjustable.

Follow circuit 12 comprises transistor Q1.Transistor Q1 has first end 221, the second end 223 and control end 222.Wherein the first end 221 of transistor Q1 couples first input end 121 and the voltage source of follow circuit 12.The control end 222 of transistor Q1 couples the second input 122 of follow circuit 12 and the output 112 of filter circuit 11.In illustrated embodiment, the control end 222 of transistor Q1 couples the first end 211 of capacitor C 2 in filter circuit 11.The second end 223 of transistor Q1 couples the output 123 of follow circuit 12.Wherein the output 123 of follow circuit 12 couples load.The output signal OUT of ripple suppression circuit 2101 outputs is the current signal Iout that flows through transistor Q1 the second end 223, and current signal Iout is proportional to the current signal i2 of control end 222, and iout=β * i2, and wherein β is the current amplification factor of transistor Q1.And current signal i2 follows filtering voltage Vc value and change, and therefore, output current iout also follows filtering voltage Vc, and its amplitude is comparatively level and smooth, thereby has suppressed ripple.In illustrated embodiment, follow circuit 12 comprises N-type bipolar junction transistor (BJT) Q1, wherein the first end 221 of transistor Q1 is collector electrode, the second end 223 is emitter, control end 222 is base stage, wherein the emitter current iout direct ratio of transistor Q1 and greater than the base current i2 of transistor Q1.In one embodiment, transistor Q1 is the P transistor npn npn.In another embodiment, follow circuit 12 comprises circuit or the device that has arbitrarily the electric current enlarging function, makes the electric current direct ratio that flows through follow circuit 12 outputs 123 and greater than the electric current that flows through follow circuit 12 second inputs 122.In one embodiment, the second input 122 of follow circuit 12 contains dead resistance.

Fig. 3 shows the ripple suppression circuit 310 according to another embodiment of the utility model.Ripple suppression circuit 210 in Fig. 2, the follow circuit 12 in ripple suppression circuit 310 further comprises the second resistance R 2.Wherein the second resistance R 2 has first end 331 and the second end 332.The first end 331 of the second resistance R 2 couples the output 112 of filter circuit 11 and the second input 122 of follow circuit 12.In illustrated embodiment, the first end 211 of the first end 331 coupling capacitance C2 of the second resistance R 2.The second end 332 of the second resistance R 2 couples the control end 222 of transistor Q1.In one embodiment, the second resistance R 2 is used for the electric current that transistor Q1 control end 222 is flow through in restriction.Other parts in ripple suppression circuit 310 can have with the corresponding part of ripple suppression circuit 210 identical structure, function and alternate embodiment, are described clearly succinctly in order to make, and this part is repeated no more.

Fig. 4 shows the ripple suppression circuit 410 according to the another embodiment of the utility model.Compare the ripple suppression circuit 310 in Fig. 3, the follow circuit 12 in ripple suppression circuit 410 comprises Darlington transistor Q3.Darlington transistor Q3 can improve the multiplication factor of electric current, reduces the power consumption of ripple suppression circuit 410.Other parts in ripple suppression circuit 410 can have with the corresponding part of ripple suppression circuit 310 identical structure, function and alternate embodiment, are described clearly succinctly in order to make, and this part is repeated no more.

Fig. 5 shows ripple suppression circuit 510 schematic diagrames that comprise mos field effect transistor (MOSFET) according to the utility model one embodiment.Ripple suppression circuit 510 comprises filter circuit 11 and follow circuit 52.Wherein follow circuit 52 comprises MOSFET pipe M2.Wherein the source electrode 521 of MOSFET pipe M2 couples first input end 121 and the voltage source of follow circuit 52, the drain electrode 523 of MOSFET pipe M2 couples output 123 and the load of follow circuit 52, and the grid 522 of MOSFET pipe M2 couples the second input 122 of follow circuit 52 and the output 112 of filter circuit 11.The drain voltage of MOSFET pipe M2 is followed and the grid voltage of amplifying MOSFET pipe M2, and the grid voltage of MOSFET pipe M2 is followed filtering voltage Vc, therefore MOSFET manages the drain electrode end 523 voltage follow filtering voltage Vc of M2, the voltage Vin of relative source terminal 121, drain electrode end 223 voltages have lower ripple.At this moment, the output signal OUT of follow circuit 52 is voltage signal, i.e. the voltage signal of MOSFET M2 drain electrode end 523.

In addition, in certain embodiments, the output signal OUT of follow circuit is power signal, makes the power following filtering voltage of follow circuit output.

Fig. 6 shows LED electric power system 600 schematic diagrames according to the utility model one embodiment.Electric power system 600 comprises voltage source 620, ripple suppression circuit 310 and load 30.

Wherein voltage source 620 comprises voltage conversion circuit.Illustrated voltage conversion circuit is single-stage PFC voltage conversion circuit.Single-stage PFC voltage conversion circuit 620 converts input ac voltage to direct voltage, in output 622 outputs.Single-stage PFC voltage conversion circuit 620 comprises transformer T, main switch M1 and with the former limit controller 63 of Active PFC function.At the secondary of transformer T, through the filtering of rectifier D rectification and output capacitance C1, at output 622 output dc voltages.In a further embodiment, ripple suppression circuit 310 in embodiment of the present utility model can be applicable to the voltage source of other topologys or form, as non-isolated voltage source, multistage Active PFC voltage conversion circuit etc., for reducing the ripple of voltage source voltage, be used to load supplying.Voltage source 620 its output current when not adopting the output capacitance C1 of Da Rong value contains larger ripple.After adopting ripple suppression circuit 310, in the situation that output capacitance C1 adopts the less ceramic disc capacitor of appearance value, the ripple of the output current of electric power system 600 also can be lowered.

In the embodiment of Fig. 6, load 30 comprises the LED lamp string that a plurality of LED of series connection form.The second end 223 of the transistor Q1 of ripple suppression circuit 310 is the output of ripple suppression circuit 310, and output current or voltage are used for driving LED lamp string 30.Certainly, as mentioned above, load 30 also can be other form.

Fig. 7 shows the electric power system that contains short-circuit protection circuit 70 700 schematic diagrames according to the utility model one embodiment.Electric power system 700 comprises voltage source 20, ripple suppression circuit 410, load 30 and short-circuit protection circuit 70.Short-circuit protection circuit 70 comprises voltage detecting circuit 701 and switch Q2.Wherein voltage detecting circuit 701 has the first end 71 that couples follow circuit 12 first input ends 121 and the second end 72 that couples follow circuit 12 outputs 123.Voltage detecting circuit 701 characterizes the signal of the voltage difference between follow circuit 12 first input ends 121 and output 123 in node 73 outputs.Switch Q2 has first end 74, the second end 76 and control end 75, wherein the first end 74 of switch couples the second input 122 of follow circuit 12, the second end 76 couples the output 123 of follow circuit 12, and control end 75 couples the output 73 of voltage detecting circuit 701.When load 30 short circuit, the electric voltage exception between follow circuit 12 first input ends 121 and output 123 raises, and switch Q2 conducting makes electric current pass through switch Q2 by-path turn-on, has protected the follow circuit 12 in ripple suppression circuit 410.

In illustrated embodiment, voltage detecting circuit 701 comprises the 3rd resistance R 3 and the 4th resistance R 4.Wherein the 3rd resistance R 3 and the 4th resistance R 4 series connection.The 3rd resistance R 3 one ends couple the first end 71 of voltage detecting circuit 701 and the first input end 121 of follow circuit 12, and the output that the other end couples voltage detecting circuit 701 is node 73.The output that one end of the 4th resistance R 4 couples voltage detecting circuit 701 is node 73, and the other end couples the second end 72 of voltage detecting circuit 701 and the output 123 of follow circuit 12.In illustrated embodiment, voltage detecting circuit 701 further comprises the 3rd capacitor C 3, and wherein capacitor C 3 and the 4th resistance R 4 parallel connections are coupled in the 4th resistance R 4 two ends.In illustrated embodiment, switch Q2 is the BJT transistor.If load 30 short circuits in electric power system 700, load both end voltage Vout is close to zero.Voltage difference between follow circuit 12 first input ends 121 and output 123 is up to Vin, and this power consumption that follow circuit 12 is consumed is very high, and transistor Q3 might damage.It is that the voltage Vbe of transistor seconds Q2 approximates that the bleeder circuit that resistance R 3 and resistance R 4 forms makes switch:

$V_{\mathrm{be}}=(V_{\mathrm{in}}-\mathrm{Vout}).\frac{R_4}{R_4+R_3}---\left(1\right)$

In when normal operation, voltage Vin-Vout is the input 121 of transistor Q3 and the voltage between output 123, be worth very lowly, and the voltage Vbe of transistor seconds Q2 is less than the conducting voltage of transistor seconds Q2 at this moment, and transistor Q2 is in off state; When load 30 was short-circuited, voltage Vout was zero,

$V_{\mathrm{be}}=V_{\mathrm{in}}\·\frac{R_4}{R_4+R_3}---\left(2\right)$

Select suitable resistance R 3 and the resistance of resistance R 4, the Vbe of this moment is greater than the conducting voltage of transistor seconds Q2, transistor Q2 conducting, and short circuit current is through transistor seconds Q2.Under load 30 short-circuit conditions, transistor seconds Q2 is operated in switching mode, so power consumption consumption is lower.Capacitor C 3 can prevent the voltage spine of output voltage V out and cause the erroneous trigger conducting of transistor seconds Q2.In certain embodiments, switch Q2 is the transistor that is different from other type of bipolar transistor, as mos field effect transistor.Ripple suppression circuit also can have other structure, as Fig. 2, and the structure such as shown in Figure 3.

Set forth according to suppressing the method for ripple current in the LED electric power system of the utility model one embodiment below in conjunction with Fig. 6.The method of this inhibition ripple current comprises the AC equivalent resistance that increases output stage in electric power system 600.Wherein the output stage of electric power system 600 comprises ripple suppression circuit 310 and LED load 30, the AC equivalent resistance of output stage is the AC equivalent resistance after voltage source 620 outputs 622, i.e. ripple suppression circuit 310 and LED load 30 forms the AC equivalent resistance of modules.The AC equivalent resistance of output stage is larger, and the alternating component of output current is less, and namely the ripple current of output is less, reaches with this purpose that suppresses ripple current.Ripple suppression circuit in a plurality of embodiment of the present utility model can be used for increasing the AC equivalent resistance of electric power system output stage.In working order, transistor Q1 conducting, the output voltage interchange value of supplying with LED lamp string 30 is:

v _LED＝i _LED·R _{LED_AC} (3)

V wherein _LEDRepresent the alternating voltage in LED load 30, i _LEDThe alternating current of load LED, R are flow through in representative _{LED_AC}Represent the AC resistance of LED load 30.

The ac voltage at capacitor C 2 two ends is:

v _c＝i _LED·R _{LED_AC}+i ₂·R ₂ (4)

Formula 3 and formula 4 are substituted into following formula can be got:

$v_{\mathrm{in}}=v_c+{\mathrm{<figure-callout\; id="1"\; label="i"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">i</figure-callout>}}_1\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1=v_c+(i_2+\frac{v_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">c</figure-callout>}}}{\frac{1}{{\mathrm{sC}}_2}})\&CenterDot;R_1$ (5)

$=i_{\mathrm{LED}}\&CenterDot;R_{\mathrm{LED}\_\mathrm{AC}}+i_2\&CenterDot;R_2+(i_2+\frac{i_{\mathrm{LED}}\&CenterDot;R_{\mathrm{LED}\_\mathrm{AC}}+i_2\&CenterDot;R_2}{\frac{1}{{\mathrm{sC}}_2}})\&CenterDot;R_1$

Wherein the alternating current of resistance R 1 is flow through in the i1 representative.

Therefore, the alternating current resistance Zin of ripple suppression circuit 310 is:

$Z_{\mathrm{in}}=\frac{v_{\mathrm{in}}}{i_{\mathrm{in}}}=\frac{v_{\mathrm{in}}}{i_{\mathrm{LED}}}=R_{\mathrm{LED}\_\mathrm{AC}}+\frac{i_2}{i_{\mathrm{LED}}}\&CenterDot;R_2+(\frac{i_2}{i_{\mathrm{LED}}}+\frac{R_{\mathrm{LED}\_\mathrm{AC}}+\frac{i_2}{i_{\mathrm{LED}}}\&CenterDot;R_2}{\frac{1}{{\mathrm{sC}}_2}})\&CenterDot;R_2$

$=R_{\mathrm{LED}\_\mathrm{AC}}+{\mathrm{sC}}_2\&CenterDot;R_{\mathrm{LED}\_\mathrm{AC}}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+\frac{1}{\mathrm{\&beta;}}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+R_2+{\mathrm{sC}}_2\&CenterDot;R_2\&CenterDot;R_1)$

(6)

Wherein β is transistor Q ₁The ratio of emitter current and base current.This shows, when the appearance value of the resistance that increases resistance R 1 and/or capacitor C 2, AC equivalent resistance increases thereupon, makes the ripple of the output current that flows through LED30 reduce.Increase the resistance of resistance R 2 and reduce β and also can reduce the ripple of output current.

In conjunction with Fig. 6, the power consumption of ripple suppression circuit 310 is:

${\mathrm{<figure-callout\; id="100"\; label="p"\; filenames="HDA00002638613200011.png"\; state="\{\{state\}\}">p</figure-callout>}}_{100}=i_{\mathrm{LED}}\&CenterDot;v_{\mathrm{ce}}=i_{\mathrm{LED}}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="i"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">i</figure-callout>}}_1\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+i_2\&CenterDot;R_2+v_{\mathrm{be}})=i_{\mathrm{LED}}\&CenterDot;((i_2+\frac{{\mathrm{<figure-callout\; id="1"\; label="v\; c"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">v</figure-callout>}}_c}{\frac{1}{{\mathrm{sC}}_2}})\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+i_2\&CenterDot;R_2+v_{\mathrm{be}})$

$=i_{\mathrm{LED}}\&CenterDot;(i_2\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+R_2+s{C}_2\&CenterDot;R_2\&CenterDot;R_1)+i_{\mathrm{LED}}\&CenterDot;R_{\mathrm{LED\; AC}}\&CenterDot;{\mathrm{sC}}_2\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+v_{\mathrm{be}})$

$=i_{\mathrm{LED}}\&CenterDot;(\frac{i_{\mathrm{LED}}}{\mathrm{\&beta;}}\&CenterDot;({\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+R_2+s{C}_2\&CenterDot;R_2\&CenterDot;R_1)+i_{\mathrm{LED}}\&CenterDot;R_{\mathrm{LED}\_\mathrm{AC}}\&CenterDot;{\mathrm{sC}}_2\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00002638613200021.png"\; state="\{\{state\}\}">R</figure-callout>}}_1+v_{\mathrm{be}})$

(7)

As shown in formula (7), if adopt resistance R 1 and/or the R2 of less resistance, than the capacitor C 2 of low-capacitance and larger β, power consumption will be lower.Otherwise if increase the resistance of resistance R 1 and R2, the appearance value that increases capacitor C 2 and reduction factor beta, power consumption will increase.Reach for the resistance R 1 that obtains the balance that reduces current ripples and control power consumption, can choose the transistor Q1 that contains larger β value and larger resistance, R2 with than capacitor C 2 values of Da Rong value the adjusting of compromising.In one embodiment, reduce power consumption by adopting Darlington transistor, because Darlington transistor has higher β value.

In conjunction with formula (6) and formula (7) as can be known, if β is enough large, in formula (6) and formula (7)

Composition can be ignored, and only needs to realize suppressing ripple current and the compromise adjusting that reduces power consumption by the value of regulating resistance R1 and capacitor C 2, can select according to specific needs to reduce the degree of ripple current and the degree of power consumption.In one embodiment, resistance R 1 and capacitor C 2 are adjustable resistance.Therefore, in one embodiment, the method that suppresses ripple further comprises the compromise adjusting that realizes suppressing ripple current and reduction power consumption by control capacittance C2 and resistance R 1.

Some above-mentioned specific embodiments only describe the utility model in an exemplary fashion, and these embodiment are not fully detailed, and are not used in the scope of the present utility model that limits.It is all possible changing and revise for disclosed embodiment, the selectivity embodiment that other are feasible and can being understood by those skilled in the art the equivalent variations of element in embodiment.Other variations of embodiment disclosed in the utility model and modification do not exceed spirit of the present utility model and protection range.

Claims (10)

1. a ripple suppression circuit, is characterized in that, described ripple suppression circuit comprises:

Filter circuit has input and output, and the input of wherein said filter circuit couples voltage source, the output output filtering voltage of described filter circuit; And

Follow circuit, have first input end, the second input and output, the first input end of wherein said follow circuit couples described voltage source, and the second input of described follow circuit couples the output of described filter circuit, and the output of described follow circuit couples load.

2. ripple suppression circuit as claimed in claim 1, is characterized in that, described filter circuit comprises:

Electric capacity has first end and the second end, and the first end of wherein said electric capacity couples the output of described filter circuit, and the second end of described electric capacity couples with reference to ground; And

Resistance has first end and the second end, and the first end of wherein said resistance couples the input of described filter circuit, and the second end of described resistance couples the first end of described electric capacity.

3. ripple suppression circuit as claimed in claim 1, it is characterized in that, described follow circuit comprises transistor, described transistor has first end, the second end and control end, wherein said transistorized first end couples the first input end of described follow circuit, described transistorized control end couples the second input of described follow circuit, and described transistorized the second end couples the output of described follow circuit.

4. ripple suppression circuit as claimed in claim 3, is characterized in that, described transistor comprises Darlington transistor.

5. ripple suppression circuit as claimed in claim 3, it is characterized in that, described follow circuit further comprises the second resistance, described the second resistance has first end and the second end, the first end of wherein said the second resistance couples the output of described filter circuit, and the second end of described the second resistance couples described transistorized control end.

6. an electric power system, is characterized in that, described electric power system comprises the described ripple suppression circuit of claim 1-5, and voltage source and load.

7. electric power system as claimed in claim 6, is characterized in that, described voltage source comprises single-stage Active PFC voltage conversion circuit.

8. electric power system as claimed in claim 6, is characterized in that, described load comprises the LED lamp.

9. electric power system as claimed in claim 6, is characterized in that, described electric power system further comprises short-circuit protection circuit, and described short-circuit protection circuit comprises:

The 3rd resistance is coupled between the first input end and a node of described follow circuit;

The 4th resistance, and described the 3rd resistance series connection, described the 4th resistance is coupled between the output of described node and described follow circuit; And

Switch has first end, the second end and control end, and the first end of wherein said switch couples the second input of described follow circuit, and the second end of described switch couples the output of described follow circuit, and the control end of described switch couples described node.

10. electric power system as claimed in claim 9, is characterized in that, described electric power system further comprises the 3rd electric capacity, and described the 3rd electric capacity and described the 4th resistance are in parallel, is coupled in the two ends of described the 4th resistance.

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